Keywords

These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

26.1 Introduction

The present agricultural practices mainly depend on high-priced inputs like mineral fertilizers to attain a high yield and also involve the application of chemical pesticides against relevant pathogens and pests. The application of chemical fertilizers not only extensively damages the helpful microbes in the soil but also causes detrimental effects on human health as well as environmental hazards, and reduces the soil fertility. It is now well established that application of nitrogen can result in nitrate leaching through the soil profile due to groundwater contamination. The issues and concerns about the destructive effects of using increasing amounts of chemical fertilizers have led to a strong move toward alternative strategies to ensure high yields coupled with crop safety and protection.

The indiscriminate use of hazardous pesticides and herbicides could result in diverse changes in the biological balance, increasing the incidence of lethal diseases like cancer, through undesirable harmful residues present in the produce. Industrialized production methods have clearly shown several limitations indicating global contamination of the food chain and water through toxic pesticide residues and a reduced nutritive value of food in cultivation practices carried out by farmers.

Because of these adventitious properties, tomato producers often use large amounts of chemical fertilizer, which is not sustainable due to the ill effects on the soil and environment through the high involvement of non-renewable energy in production input used to ultimately enhance the yield and quality of crops. The modern approach, often referred to as organic agriculture, seeks to introduce agricultural cultivation practices that are eco-friendly and maintain the sustainable ecological balance of the ecosystem. The growth pattern of organic agricultural land has increased tremendously from 1999 to the present time (Fig. 26.1).

Fig. 26.1
figure 1

Growth of organic agricultural land (1999–2013) (Source-ICCOA)

Full size image

Organic matter is an excellent source of available nutrients, and their incorporation in soil can maintain high activity of microbial populations with increased values of biomass content, basal respiration, and total organic carbon (Tonfack et al. 2009).

The poor health of soil due to disease contamination after repeated use and the desire to implement optimal conditions for plant growth have led to the modern trend of growing plants in soil-less media. While soil-less media incur additional costs for growing systems and chemical fertilizers, they offer earlier growth and higher yields.

The biopriming of seeds with beneficial microorganisms provides long-term protection from yield-threatening fungal or bacterial diseases by creating a protection shell around the seed- root system, which provides a stronger and healthier root system leading to increased crop productivity and gradually to better yields. Trichoderma harzianum and Trichoderma viride are two widely used species that have been used for about 87 different crops, 70 and 18 soil and foliar pathogens, respectively (Sharma et al. 2014).

Organic agriculture is a multidirectional management system that furnishes the health of the agrological ecosystem. Sustainable farming, quality of food, and human health argue that environmental agents should be directed toward organic products. The use of management practices via the off-farm inputs require locally adapted systems taking into account the prevailing regional conditions. This is accomplished by using diverse methods such as agronomic, biological, and mechanical methods as opposed to using synthetic materials to fulfill any specific function. The focus is on maintaining soil fertility for generations, producing poison-free food for consumers, securing productivity, meeting competition from likely cheaper imports, achieving high water percolation, recharging groundwater, developing nitrogen- and phosphate-fixing microbes involved in transferring atmospheric moisture, soil enrichment through transfer of biomass from agro-waste, emergence of mixed farming systems, new marketing channels, premium prices, and higher product demand, on a worldwide basis (Figs. 26.2 and 26.3).

Fig. 26.2
figure 2

The ten countries with the largest number of organic producers (2013) (Source: ICCOA)

Full size image
Fig. 26.3
figure 3

Organic agriculture worldwide: statistics (Source: ICCOA)

Full size image

Global markets for organic products are growing, hence satisfying the criteria for food safety (less incidence of diseases like mad cow disease and cancer, etc.), health aspects (over 20% more vitamins and minerals), price premiums, environmental concerns, and sustainability.

Parameters highlighting food security and safety are of primary concern to each individual. Thus, quality can be defined as a strong characteristic of food that determines the value of acceptability to a consumer. The increasing consumer awareness about the relationship between food, health, and environmental concerns has led to the increasing demand for organically cultivated food.

Organic food commodities contain lower pesticide and nitrate levels than conventionally grown fruit and vegetables. This may be considered beneficial in relation to antioxidants (polyphenolic compounds). Organic foods do not involve the use of synthetic fertilizers; they possess efficient biochemical energy to synthesize the important secondary plant metabolites as well as naturally occurring toxins. The present scenario of tomato production by the farmers is confined to the conventional open-field cultivation system with varied agro-climatic conditions in the Solan district of Himachal Pradesh. The favorable positioning of the State in the Himalayan region provides a great scope for the implementation of organic farming. The policies framed by the State government on organic farming in 2010 relate to 30,110 farmers with an area of 17,848 ha with a future vision in mind of converting around 200 villages to complete bio-villages. However, the government has already initiated the process of registration and certification for using organic fertilizers to organically cultivate tomatoes, but the farmers are still unaware of the incorporation of organic recommendations.

The economic parameter in organic farming stands out as an important issue to the farmers. Beneficial economics with good incentives will be the greatest boost for the adoption of organic practices in crop husbandry. Achieving circumstances that direct favorable economic conditions for organic farming becomes a priority. The history of organic tomato in HP is only 3–4 years. Although farmers have gradually been shifting to organic practices, the switch-over is not complete in the majority of cases. They have not been able to develop the mindset required for organic cultivation of tomatoes. Many farmers are not ready to put in the labor required for the preparation of inputs under the organic system; they look to markets for input supply. The shift has been gradual and the change in mindset even slower. However, many inorganic farmers are presently realizing the deleterious effects of using hazardous products on human health and the environment. Hence, they are in the process of reducing the doses and frequency of chemical products and relying more on farmyard manure (FYM), vermicompost (VC), and biofertilizers.

26.2 Organic Farming Systems: Quantity Coupled with Quality

Considering the ill effects on natural resources and global marketing demand for quality products, there is a need to switch from intensive chemical cropping systems to organic farming systems that will not only help in yield sustainability (Fig. 26.4) (Barbier 1987) but also earn higher foreign exchange from export (Jangir et al. 2008). On other hand, the small farmers with less than 1 ha of land are facing many problems related to debt, vagaries of rainfall and nature, lack of investment, and soil fatigue. The food quality concept can be defined in many different ways, such as through the quality of the fresh produce, which is often judged by examining the visual characteristics such as size, shape, and color. The present review deals with a combinatorial study and breakthrough aimed at differentiating between conventional and organic farming systems, thus ensuring the realization of the criteria of good soil fertility, nutrition, quality, productivity, yield, economics, and food security and safety of vegetable crops and fruit. This review highlights those aspects of nursery management, soil fertility, crop yield, productivity, economics, and food quality, which are the most crucial for the promotion of good health, specifically focusing on the available evidence for four criteria:

  • Safety and security of food

    The first question relates to the extent of organic and non-organic foods that contain potentially harmful chemicals and pathogens.

  • Primary nutrients

    The second question deals with the contribution of organic and non-organic foods toward a balanced diet.

  • Secondary nutrients

    The third question focuses on the effect of different farming practices on the concentration and range of secondary plant compounds.

  • Microbiological hazards

    The fourth question focuses on the final test of nutritional quality for a food to support growth and development thus reducing the microbiological hazards.

Fig. 26.4
figure 4

Scheme of sustainable development (Source: Barbier 1987)

Full size image

26.3 Effect of Microbial and Inorganic Fertilizers

26.3.1 Disease-Free Nursery Management

The necessity of healthy seed selection integrated with nursery raising (free from disease) is the most important requirement for achieving better crop performance in addition to lower abiotic and biotic yield constraints and lower incidence of insect-pest-disease (IPD), in order to achieve attractive economic returns for the farmers. The reduction witnessed in potential yield in hills by the farmers is due to the increasing incidence of pre- and post-emergence insect pests and diseases from the initial nursery raising to the final period of harvesting, where the incidence of serious diseases like damping off (Pythium aphanidermatum), fusarial wilt (Fusarium oxysporum), bacterial wilt (Ralstonia solani), etc., can be seen to be drastically ruining the crop diversity and quality. This review thus discusses healthy nursery management through various organic approaches.

The history of biological control can be traced back to the era of 1965, where the interactive ideas of Baker and Synder (Baker and Snyder 1965) emphasized the significance of the biocontrol formulations. Expanding these valuable ideas, biocontrol agents have gained momentum in nursery management, seedling germination, seedling vigor, and disease control in recent times as these technologies not only minimize the hazardous aspects of chemicals but are also found to be cheap and efficient in disease-control strategies. With the advent of biological control practices, several successful uses of fungal biocontrol agents like Trichoderma spp. have been investigated for controlling the soil-borne diseases caused by pathogens like Sclerotium, spp., Fusarium, Pythium, and Phytophthora (Cook and Baker 1983). The increased concern for environmental awareness, safety, and security of chemicals has evoked an interest in inbuilt microbial control of pathogens. In this regard, many microorganisms have been exploited as significant biocontrol agents for successful nursery raising and management. Trichoderma spp., (Raguchander et al. 1997), Bacillus spp., (Copper and Campbell 1986), and Pseudomonas spp. (Vidyasekaran et al. 1997) are specially incorporated in terms of the formulation and delivery system for research because of their abundant natural occurrence, biocontrol potential against fungal and nematode diseases, and host defense. Trichoderma has gained maximum attention as a biocontrol agent due to the fact that it is effective against a large number of soil-borne plant pathogenic fungi, has suppressive effects on some root nematodes without adversely affecting beneficial microbes like Rhizobium, and is capable of promoting growth of certain crops.

Various types of compost have been employed advantageously in nursery management, generally prepared by combining carbonaceous wastes such as sawdust with nitrogen and other nutrients contained in the manure (Galler et al. 1978) and also sewage sludges (Anonymous 1982). The pathogens are difficult to manage by chemical methods and there is a current interest to promote their biological management. The suppression of disease caused by soil-borne pathogens on application of vermicompost has been reported (Jack 2010). In the earlier in vitro studies, it was found that certain soil-borne fungal and bacterial plant pathogens are suppressed by earthworm exudates (Reddy et al. 2012).

The results of in vitro antimicrobial assay and pot culture studies conducted earlier (Agbenin and Marley 2006) formed the basis on which to evaluate the effects of seed treatment with aqueous extracts (10%) of vermicompost prepared from different substrates (agricultural wastes, leaves of Azadiracta indica (neem), Parthenium hysterophorous (parthenium) and Lantana camara (lantana)), and soil application of vermicomposted neem. The response of susceptible crops, e.g., tomato (Lycopersicon esculentum) and egg plant (Solanum melongena) in the infected fields were evaluated for developing effective biological management. Application of vermicompost alone was not enough for protecting the plants against disease, but combining the same with aqueous seed treatment is necessary to achieve complete disease uprooting and an increase in yields (Reddy et al. 2012).

Various studies have focused on the use of botanicals in combination with arbuscular mycorrhizal fungi (AMF) recording higher crop uniformity, better mineral uptake (Bethlenfalvay et al. 1988) and improved tolerance to soil-borne pathogens (Pozo and Azcon Aguilar 2007). Evidence from several studies highlights the activities of soil-borne pathogens and their antagonists, which are greatly influenced by the presence of various plant products present in the soil. These beneficial products not only alter the physiochemical characteristics of the soil, but also increase the density of antagonist inoculums by serving as a substrate medium for their growth (Champawat and Sharma, 2003; Neelamegam and Govindarajalu, 2002), which further results in overall suppression of diseases. The most devastating fungal disease is the damping off caused by Pythium phytopthora, Fusarium spp., and Sclerotium spp., which results in 50–60% losses in nursery plants (Srivastava and Singh 2000). Damping off is a serious disease of tomato nurseries that results in high seedling mortality. The findings of Kabdal et al. (2010) incorporated single and combined formulations of biocontrol agents, namely Trichodema herzianum 0.4% and Pseudomonas fluorescens 1.0% for the healthy management of capsicum nursery. All biological formulations were found to be significantly effective in increasing seedling emergence (71.9%) and vigor (135.2%) with marked decreases in pre-emergence rot (52.5%).

To tackle the increasing incidence of damping off of tomato under mid-hill conditions of the north western zone of the Himalayas, Hooda et al. (2011) highlighted the combinatorial selection of 17 locally available plant extracts (10% w/v) (Lantana camara (@10%), neem-based commercial formulations (10% w/v), botanical fungicide, raw neem oil (0.05% v/v), neem cake extract , cow urine (20% v/v), and cow dung ash. Among the selected extracts, i.e. Thuja compacta, Azadirachtin (Achook), neem cake extracts, cow urine and dung formulations were found to be the most promising for the management of pre-damping off and also significantly increased the mean seedling emergence (60.1%) and vigor (81.3%) in tomatoes treated with Lantana camara extracts as compared to the uninoculated controls. The study clearly indicated that the treatment of tomato seeds with extracts of Lantana camara, neem cake, and cow urine can be effectively utilized as a cost-effective, eco-friendly, and suitable alternative method for hilly areas where pesticide availability is scarce. The incorporation of plant growth–promoting rhizobacteria (PGPRs) with BCAs has been successfully integrated in tomatoes (Muthuraju et al. 2002) and green grams (Thilagavathi et al. 2007). Srinivasan and Mathivanan (2011) recorded a gradual increase in tomato seedling growth and a reduction in disease incidence both in nurseries and under field conditions with the use of a consortium of antagonist fungi alone and in combination with PGPR and biocontrol agents. The studies conducted by Kumar et al. (2010) focused on the development of modern strategies for the management of damping off on tomatoes caused by Pythium aphanidermatum with maha panch gavya (MPG), in combination with biocontrol agents (neem products) in nursery beds. Soil application of MPG with neem cakes in nursery beds improved seedling stand (63%), seedling height (27.09 cm), and decreased seedling mortality with high disease control (100%) in inoculated soil, thus ensuring one of the major components in managing plant diseases, especially soil-borne diseases, in organic farming.

Recent research carried out in Bangalore (Sudharani et al. 2014) highlights the effectiveness of selected bio-control agents in combination against damping off and wilt pathogens of cabbage crop. The results revealed that the treatment combination recorded highest germination percentages (91% and 95%, respectively) and took a minimum of days for 50% germination over pathogen-inoculated treatment. A maximum reduction of pre- (9.09%) and post- (6.14%) damping off was reported in Treatment T10 on a par with T12.

The combination of Azotobacter chroococcum + Bacillus megaterium + Pseudomonas fluorescens + Bacillus subtilis + Trichoderma harzianum showed enhanced seedling vigor, total biomass, least disease incidence, and more biocontrol efficiency.

26.3.2 Soil Fertility, Health, and Quality

The improvement in soil fertility in organic farming through the use of composts and on-farm input relies on improved understanding about the effects of application methods on soil fertility along with the improved technology transfer of research results into practice.

The application of soil amendments has been associated with desirable soil properties including a water-holding capacity, lower bulk density, and beneficial micro-organisms (Doran 1995). A similar correlated study highlights the fact that microbial activity and biomass is recorded higher in fields with organic amendments than in conventional fields (Drinkwater et al. 1995).

Bulluck over two successive years (1996 and 1997) conducted a field experiment emphasizing examining the effects of organic and chemical soil fertility amendments on soil microbial communities along with soil physical and chemical properties at three organic and three conventional farms in Virginia and Maryland, respectively. Two treatments including use of composted yard waste or cattle manure and synthetic soil amendment were applied to three replicated plots. A canonical correlation was figured out, which showed more negativity in fields with conventional history and synthetic fertilizers in comparison with the positive relationship in fields with organic production. Propagated densities of Trichoderma spp., thermophilic microorganisms, and enteric bacteria were higher in soils of organic fields. The concentration of major elements (calcium (Ca), potassium (K), magnesium (Mg), and manganese (Mn)) was also reported to be higher. On the whole, organic application resulted in increased beneficial soil microorganisms, reduced pest-pathogen population, and increased soil organic matter, thus improving soil health and fertility. The application of compost amendments results in providing benefits including pH stabilization and faster water infiltration rate (Stamatiadis et al. 1995). The integration of manures and composts tend to positively increase soil organic matter content thus reducing bulk density and increasing porosity, which in turn will have a significant impact on the protection of soil against erosion. This increase in the soil organic matter content is directly related to the increase in cation exchange capacity.

Sanwal et al. (2007) advocated an integrated approach toward organic manure application to assess the effects on residual soil fertility, quality, and yield parameters in turmeric. A significantly increased rhizome yield in the range of 16–103% was recorded with the application of FYM at18 t/ha, on a par with 10 t/ha poultry manure. The outcome of this approach resulted in not only the highest crop yield but also improved soil fertility and productivity.

26.3.3 Nutrient Uptake, Growth, and Yield Status

Yan et al. (2002) in his 3-month study analyzed compost maturity, which affects crop nutrient uptake, and recorded that after application of dairy cattle, swine, and poultry manure pellets released 31.5%, 41.6%, and 51.3% of nitrogen (N), respectively. A 2-year field trial was conducted by Trivedi et al. (2012) to assess the response of guava varieties to the integrated application of organic manures, inorganic fertilizers, and bio-fertilizers (2005–07). The sardar variety was recorded to have greater plant height when compared to Allahabad safeda, which registered a higher total soluble sugar (TSS), available nitrate, P2O5, and K2O content in the soil. The application of castor cake proved best for attaining maximum plant height and nitrate uptake. The incorporation of vermicompost and FYM revealed big enhancements in N, K, and carbon content. The approach led to a greatly increased high fruit yield and available P2O5 content in soil with the addition of biofertilizer.

Patel et al. (2009) conducted successive experiments over a period of 3 years to work out the influence of microbial and inorganic fertilizers in combination with 0.4% micronutrients on different growth parameters along with attributes like yield, leaf nutrient status, and resultant changes in the rhizosphere in sweet oranges. The treatment consisted of application of full dosea of N (300 g), P (250 g), K (300 g), Azospirillum (5 g), AMF (5 g), and micronutrients (Cu + Fe + B + Zn 0.4%). This integrated application of macro- and micronutrients showed a great increase in plant height, canopy spread, fruit yield, quality, and juice content. The use of AMF along with Azospirillum proved beneficial in improving biological properties of soil.

Prativa and Bhattari (2011) carried out a field experiment at the Integrated Research Farm (Himalayan College of Agricultural Sciences and Technology (HICAST)) located in Nepal during 2009, to scrutinize and study the effect of integrated nutrient management (INM) on growth parameters of tomatoes with a randomized complete block design with nine treatments replicated three times. The outcome of the study clearly indicated that the combination of organic manures with inorganic fertilizers was found to be better in improving the overall growth and soil macro-micronutrient status than the sole application of either of these nutrients. The maximum plant height and number of leaves per plant were recorded with treatment combining 16.66 m/ha FYM + 8.33 m/ha vermicompost + NPK. The highest number of clusters and maximum fruit weight and yield (25.74 mt/ha) were recorded with the treatment with 16.66 mt/ha FYM + 8.33 mt/ha vermicompost + NPK. Similarly, the maximum organic matter percentage was also observed with the treatment with an application of 10 m/ha vermicompost.

Similar types of experiments were conducted (2012) on strawberry and consisted of a combination of five successive nutrient source treatments; T1-FYM with Azotobacter, PSB and oil cake, T2-poultry manure with Azotobacter, wood ash, PSB, and oil cake, T3-FYM with Azospirillum, PSB, and oil cake, T4-poultry manure with Azospirillum, wood ash, PSB, and oil cake, and T5 comprised of the recommended dose of NPK (340:150:340 kg/ha). The results showed maximum plant growth and fruit yield (132.75 q/ha) with T2 treatment closely followed by T4. On the other hand, maximum available N (370.29 kg/ha) and phosphorus (P) (22.11 kg/ ha) were recorded with treatment T4 with a gain of 36.29 and 4.61 kg/ ha, respectively. Maximum potassium (331.79 kg/ha) was obtained with treatment T2 with a gain of 12.29 kg/ha. The varying degrees of difference were postulated in a population of bio-fertilizers that showed a maximum increase in the case of Azotobacter, PSB in treatment T2 and Azospirillum, which recorded the maximum increase with treatment T4. The highest yield and sustainability was found in T2 and T4 treatments.

Sepat Naval et al. (2012) conducted a field experiment during the kharif season of 2008 and 2009 at the Defence Institute of High Altitude Research, Leh and Ladakh, to evaluate the effect of biofertilizer, fertility levels and cow manure on growth, yield and quality of tomato var. Sultan in Trans Himalayan. Results revealed that the treatments with 100% NPK either in combination with each other or with Azotobacter had a significant effect on plant growth and economic attributes over control. However, application of 50% NPK + FYM + Azotobacter gave values of plant height (79 cm), branches (7.5), clusters of fruit (11), fruits cluster (4.8), fruit size (6.3 cm), weight of fruit (113.3 g), and fruit yield: plant (1.48 kg) and (12.3 q ha−1) that were on a par with the values obtained with 100% NPK+ FYM + Azotobacter and were significantly higher over other treatments.

Nutrient management affects both productivity and quality of produce and also contributes to input costs of production, and was fully justified by Singh et al. (2012) in their findings when they evaluated the influence of various levels of organic and synthetic nutrient sources on morphomatrix productivity and soil quality attributes of NA-7 Aonla trees during 2007–08 in a hot semi-arid ecosystem. A different application of cakes and FYM resulted in higher yield and quality. Maximum yield per plant (32.15 kg) was recorded with the plants treated with FYM and standard doses of NPK. A similar hike was observed in quality parameters like total sugars, vitamin C, and phenols with considerable improvement in soil properties.

An investigation carried out by Ramakrishnan and Selvakumar (2012) aimed at evaluating the effect of biofertilizer application on the growth and yield of tomato plants. After the transplanting process the tomato seedlings were treated with different formulations: T0-Control, T1-Azotobacter, T2-Azospirillum, and T3-Azotobacter with Azospirillum. The observations were based on recording significantly high performance in plant dry weight (g plant-1), height (cm), number of leaves per plant, number of fruits/plant, yield/plant (g), average fruit weight/plant (g), and protein content. On the whole, the treatments comprising Azotobacter with Azospirillum showed a significantly (P < 0.05) maximum yield when compared with single inoculations and control (428.41 g). The overall results suggested that inoculation combinations improve plant mineral concentration through nitrogen fixation, thereby altering fruit production in tomato plants.

The studies carried out by Chatterjee (2013) aimed to assess the influence of the integrated use of FYM, vermicompost, and inorganic fertilizers on plant nutrient uptake and the post-harvest status of tomato cultivation with 14 designed treatments. The pooled data revealed that the treatment T3 was recorded with 17% higher potassium over treatment T1. The results further pointed toward treatment T13, which was recorded as having the maximum Kcontent in fruit as well as in plant residues (2.37%). The finding also emphasized that the application in which the vermicompost was supplemented with Azophos and 75% of inorganic fertilizer resulted in a maximum uptake of macronutrients by the tomato plants. Thus, the integrated intervention of diverse sources of nutrients not only increases the plant nutrient uptake, but also improves the soil fertility post-harvest and subsequently helps to attain the much desired crop production with sustainable soil health.

Haque et al. (2013) evaluated the effect of bio slurry on the performance of vegetable crops (cabbage, spinach, and brinjal) and two oil seed mustard plants. The trial was carried out in 25 locations with 90 farmers in the country. Four nutrient management packages, namely inorganic fertilizer IPNS with poultry manure/cow dung/poultry slurry/cow dung slurry along with farmers’ practice were trialled on different vegetable crops. The workers reached the conclusion that there was increased plant height, yield, and weight per plant with all aspects, namely 0.23 g per plant using organic fertilizers like cow dung (CD), poultry manure (PM), and poultry manure (PM) slurry treatments. The yield from the poultry manure (PM) showed a reasonable increase in the growth of cabbage and showed increasing percentages from 6.9% to 11% per plant. A higher yield in brinjal was recorded in the treatment of plants in the field using organic fertilizer with bio-slurry. The yield surprisingly extended up to 90–118% over inorganic fertilizer and farmers’ practice, thus affording a good financial turnover per ha in cost return. The highest growth of spinach in the field using IPNS + bio-slurry combination was recorded with the highest economic turnover compared to T1 and T3 treatments.

26.3.4 Crop (Fruit) Quality, Yield, and Economics (Benefit-to-Cost Ratio)

The aim of the study conducted by Yanar et al. (2011) was to evaluate the effects of different organic manures on yields and fruit quality of tomato compared during growing periods under field conditions. During the initial growing period (2006), the organic fertilizers used were Ormin K, N (40 kg/ha every week), composted poultry manure (CPM), and composted cattle manure (CCM) after first flowering and 5 t/ha after first harvest (liquid form).

Based on the initial year results, organic fertilizers used in year 2007 growing periods were F1 (20 ton/ha CCM; 1 t/ha CPM used before planting; 40 kg/ha Coplex and 20 kg/ha N every week) and F2 (20 t/ha CCM before planting; 500 kg/ha Ormin K before planting; 30 kg/ha Coplex and 30 kg/ha N every week). Inorganic fertilizers used as control (N: 450, P2O5: 350, K2O: 600, CaO: 50, S: 200, and Mg: 50 kg/ha) were tested too. The tomato cultivars used in this study were Alida Fı in the 2006 growing period and Alida Fı, Yankı Fı, and Maya Fı during the 2007 growing period, respectively. During 2006, the highest yields were obtained from CPM, CCM, and control treatments. During 2007, marketable yields were the same for F1 fertilizer treatment and the control application.

There was no significant difference among the treatments. However, it was observed that fruit cracking rates were higher in organic fertilizer treatments than the inorganic fertilizer treatment.

The results indicated that parameters like firmness and color value decreased significantly in all treatments during storage. However, TSS and reducing sugar values significantly increased in fruit analysis during storage. Application of microbial fertilizers and their combination significantly affected the quality parameters. The data suggested that organically produced fruit maintain their quality during storage for a period that is comparable to that of conventionally grown fruits. Similarly, the linkage of different components of organic crop production systems (Fig. 26.5) (Stockdale et al. 2000) also plays an important role in upgrading crop quality and health.

Fig. 26.5
figure 5

Diagrammatic representation of structural and tactical components of organic production systems (Stockdale et al. 2000)

Full size image

Kapoulas et al. (2011) focused on comparing the fruit quality parameters in different tomato cultivars (Robin-F1, Amati F1, and Elfida F1) obtained from organic and conventional greenhouse production in North-Eastern parts of Greece. Higher levels of sugar and vitamin C were recorded in conventional systems, while those grown organically contained increased amounts of carotenoids. Elphida cultivar was seen with the highest content of TSS (5.08%), sugar content (4.10 mg/100 g) and lycopene (37.5 mg/kg) in three varieties. The fruit flavor in organic production was much better than the tomatoes from conventional production because of the favorable ratios of total sugar and acid. Organically grown tomatoes had a softer texture and were preferred because of their better taste and juiciness, whereas the conventional tomatoes were described as dry and having less aroma.

Six fresh market tomatoes and three processing varieties that were harvested at the “mature green” stage were evaluated for total reducing and non-reducing sugar trends as well as marketability during a period study of 32 days storage under ambient conditions (Tadesse et al. 2012). The studies were undertaken using a randomized complete block design replicated three times. These tomato varieties experienced significant effects on overall quality and maintenance. At harvest, the highest sugar content was seen in Marglobe, whereas the processing tomato variety Roma VF showed a higher sugar content than the other two processing varieties, but the two processing varieties were better in their chemical quality characteristics than the former varieties.

Kachari and Korla (2012) reported a considerable increase in yield (33.94 t/ha) with a benefit:cost ratio amounting to 1:2.58 over the uninoculated control (FYM) during 2006–2007, with objectives to evaluate the influence of biofertilizers (Azotobacter, Azospirillum, AMF, PSB-1) and inorganic fertilizers on the quality and economics of cauliflower. The randomized block design consisted of 21 treatments. The formulation of bio-fertilizers with inorganic fertilizers showed the best results as compared to control (FYM).

Choudhary et al. (2012) reported the effect of different organic sources on subsequent parameters of sprouting broccoli under semi-arid conditions of Rajasthan. A significant increase in plant height, number of leaves, leaf area, diameter of head, total head yield, and chlorophyll content in head was recorded under various organic fertility levels.

Chatterjee et al. (2014), in order to study the adequate tomato plant nutrient needs for optimum growth and yield, incorporated field work that aimed at working out the effect of different combinations (15) of organic and inorganic nutrient sources on soil and crop profile. The results revealed that the tomato parameters responding to nitrogen use were greatly influenced by the application of different nutrient sources. It was observed successively that vermicompost was found to be the best organic nutrient source over farmyard manure. Inoculation with biofertilizer showed more positive results than the uninoculated treatments.

26.3.5 Microbiological Food Quality and Safety

Food safety can be defined as the assurance of the food quality that it will not cause any harm to the consumer when it is in the preparation or eating process according to its intended use (FAO/WHO 1997). It has been estimated that 82 food-borne illness outbreaks were associated with the consumption of fresh produce during 1996–2008. This time period was linked with tomato-associated outbreaks accounting for 1,927 illnesses and three deaths. These tomato-associated outbreaks were considered fatal. There are many factors that may play a role in the increased incidence of food-borne illness outbreaks that implicate fresh produce, such as a population consisting of aged plants, more complex supply and global trade, improved surveillance participating in the detection of food-borne illness, improvement in the advances of epidemiological investigation, and upgrading to the latest methods to detect pathogens.

The European Food Safety Authority (EFSA), Parma, Italy, 2014, advised that tomatoes may be minimally processed for obtaining ready-to-eat products. These steps include initial selection to final storage. The epidemiological source from the EU has identified one outbreak of Salmonella and one of Norovirus associated with tomato consumption from 2007 to 2012, which were considered in the context of the whole food chain. Available estimates of the Salmonella and Norovirus occurrence in tomatoes were evaluated together for prevention of contamination with relevant microbiological criteria.

It was concluded that each farm habitat represents a unique collection of risk factors that can influence persistence of pathogens in tomato production. The implementation of appropriate food safety management systems including good agricultural practices and good manufacturing practices should be the most important objectives of a tomato producer. According to Lairon (2009), food nutritional value, quality, and safety vary widely around the world. Attaining these three goals is one of the major priorities for the near future. In line with several published literature reviews, the French Agency for Food Safety (AFSSA) performed a critical evaluation on the nutritional and hygienic quality of organic food. The review generally underlines the following major points:

  1. 1.

    The organic plant products are known to contain more dry matter and minerals containing more antioxidants and micronutrients such as phenols and salicylic acid.

  2. 2.

    The organic animal products contain more fatty acids (polyunsaturated).

  3. 3.

    It is believed that 94–100% of organic foods do not contain any pesticide residues.

  4. 4.

    Organic vegetables contain far less nitrates. Thus, organic agricultural systems have been shown to be able to produce food with high quality standards.

26.3.6 Risk Level of Microbial Contamination

Machado et al. (2006) attempted to evaluate organically grown horticultural crops for their microbiological safety and quality. The study outlines six different treatments that were applied to the three species of vegetables (lettuce, (Lactuva sativa), radish (Raphanus sativus), and spinach (Tetragonia expansa)), which consisted of a mineral fertilizer in combination with liquid biofertilizers.

The samples were examined for most probable number to detect the presence of Escherichia coli and Salmonella spp. They were considered acceptable if they did not contain Salmonella spp. However, most samples of vegetables like lettuce contained >102 total coliforms/g of product, whereas none of the samples of spinach or radish presented >102 fecal coliforms/g and only a smaller amount (6.6%) of lettuce samples contained >102 fecal coliforms/g.

26.3.7 Nutritional Quality of Food (Vitamins, Nutrients, Toxins, Antioxidant Activity, and Pesticide Residue)

26.3.7.1 Flavor: Sugar-to-Acid Ratio

Tomato flavor is judged by the amount of acid and sugar present in it because sugar-acid interaction is directly correlated to overall flavor intensity including sourness and sweetness in tomatoes (DeBruyn et al. 1971; Stevens et al. 1997). As a result, relatively high sugars and acids are generally required for the best flavor (Kader 1986). The main component responsible for flavor is soluble solid content and titratable acidity (Kader 1986), which is believed most likely to match the consumer perception with best internal quality (Artes et al. 1999).

26.3.7.2 Antioxidant Activity, Vitamin C, and Nitrate Levels

It is known that consumers now look for safe foods produced in a local environment that is eco-friendly. These consumer demands are believed to be satisfied by organic food as organic crops have less nitrates and reduced pesticide residues and more nutritional elements than conventional crops. In the majority of cases higher levels of phenols and polyphenols have been reported in organic food stuffs such as apples (Lucarini et al. 1999), peaches (Carbonaro et al. 2002), potatoes (Hamouz et al. 1999), onions (Ren et al. 2001), tomatoes (Mitchell et al. 2007), peppers (Perez-Lopez et al. 2007), oranges (Tarozzi et al. 2006), and olive oil (Gutierrez et al. 1999). It has been reported in a recent review (Rembiałkowska et al. 2005) that organically cultivated foods contain higher amounts of phenolic compounds. Benbrook et al. (2008) in their study indicated higher levels of polyphenols in organically produced foods in comparison to ones produced conventionally. Polyphenols represent a varied class of secondary metabolites with increasing antioxidative properties as well as preventative properties such as being neuroprotective and cardioprotective (Ortuno et al. 2007). The important group of polyphenols identified as diminishing the incidence of various diseases are found to have higher contents of flavanols (Caris-Veynard et al. 2004; Shankar et al. 2007). According to Ren et al. (2001), extracted juices from the organic spinach, onion, and cabbage had 50–120% higher antioxidant activity than the juices extracted from conventionally produced vegetables. Similarly, antioxidant activity of currants grown organically was also recorded as 30% higher than through conventional methods (Kazimierczak et al. 2008. The meta-analysis carried out by Benbrook et al. (2008) on organic crops revealed that organic food contains more beneficial substances such as quercetin, kaempferol (55%), essential vitamins, and phosphorus. On the other hand, Magkos et al. (2003) in his reports describe protein quality in some organic cereal crops and vegetables that was higher than reported in conventionally produced ones. The presence of harmful substances such as nitrates was lower in organic crops (Abu et al. 2007).

Barrett et al. (2007) emphasized the importance of their findings regarding agricultural cultivation systems, which are crucial factors in determining the food quality. The studies were carried out by comparing four different growers of tomatoes under both commercial organic and conventional systems of farming. The goal of the study was to map out the comparison between the quality and nutritional value of tomatoes under both systems of cultivation. The sole analysis of variance results indicated that tomato juice prepared organically was higher in total soluble solids (5.960 Brix) for Terranova Ranch Growers as compared to conventional tomato juice (5.560 Brix), while the grower Romenger and sons reported higher ascorbic acid (1153 μg/g), lycopene (1345 μg/g), and total phenolics (1811 μg/g) with organic cultivation.

The aim of the study conducted by Ragab et al. (2010) was to evaluate the antioxidant profile of organically and conventionally cultivated tomato and carrot samples purchased from local markets of the Al-Qassim region, (Saudi Arabia), over six successive months.

The antioxidant activity components of both systems varied throughout the period of study. It was observed that the antioxidant activity coupled with antioxidant components was in a higher range than in the conventional tomatoes. In contrast, a smaller antioxidant capacity and vitamin C content were observed in organic carrots.

The nutritional constituents present in tomato and carrot showed their response to this production method. The organic tomatoes had higher values of nutritional contents (dry matter, soluble sugars, and oils) than conventional ones, whereas with organic carrots, higher levels of protein and minerals and lower sugar content were recorded as compared with conventional cultivation. Tomatoes were analyzed for ascorbic acid, phenolic compounds, lycopene content, and antioxidant activity.

Oliveira et al. (2013) in their recent study showed that tomatoes that were grown organically contained more vitamin C and sugars than conventional tomatoes. In the present research, the weights and biochemical properties of tomatoes from both systems of cultivation were compared. The outcome showed that tomatoes grown organically were approximately smaller (about 40%), accumulated more compounds, and thus developed more stress-linked conditions than under conventional techniques. This increased stress may be the reason organic tomatoes have higher sugar levels, vitamins, and pigment molecules. Based on these findings, the researchers suggested that strategies developed for fruit and vegetable cultivation should focus on plant stress management with efforts to increase yield and stabilize fruit size.

The development of nutritional management techniques plays a significant role in improving the overall quality of tomatoes. This fact was truly justified by the field studies conducted in New Delhi (India) with chemical fertilizers and control treatments (effective microorganisms (EM) with compost alone and in combination) on the evaluation of compost on the antioxidant activities and defense enzyme activities of tomatoes. The results revealed an increase of 31.83% tomato yield with the combined use of compost and half the recommended doses of chemical fertilizers (N50 + P30 + K25 + EM compost @ 5 t/ha). A significant increase in fruit quality in terms of lycopene content (35–63%), antioxidant activity (24–63%), and defense activity (11–54%) traced a positive correlation among fruit quality parameters with beneficial soil microbiological activities. This ultimately led to the conclusion that the positive impact exerted by EM compost could be adopted as an eco-friendly method for high quality product production.

Studies carried out in Greece compared ten types of olives, 11 types of tomatoes, and 18 types of legumes from conventional and organic farming for important nutritional properties. Natural black olives exhibited higher TAC (44.15) and total phenolic content. Natural green olives showed higher TAC (44.15 μmol FeSO4/g) and total phenolic content (0.79 mg/GAE/g) than Spanish style green olives. Organic lentils exhibited lower predicted iron bioavailability than conventional lentils (% dialyzable iron 3.07 and 8.9, respectively, and % ferrous dialyzable iron 2.76 and 7.04 mg/GAE/g, respectively). In legumes, differences in total or ferrous iron dialyzability were observed. Giant and elephant beans exhibited the highest total iron dialyzability, while lentils the lowest. Likewise, in the organic and conventional type of “formula” tomatoes a small difference was also observed (p¼0.04). However, no differences were observed between conventional and organic types of tomato pulp (p¼0.31). The highest amount of dialyzable iron was found in “cherry” and “santorini” tomatoes. The organic tomato cherry cherellino yielded 6.8215 μmol Feso4/g total antioxidant activity, 1.31 mg/GAE/g total phenolics, 0.23 mg/g ascorbic acid and percent dialyzable Fe (50.90%), and Zn (52.30%) as compared to conventional ones.

26.3.8 Pesticide and Toxin Residue Levels

Pesticides are used in controlling serious threats caused by insects, diseases, and weeds in agriculture. Increasing pesticide concentration affects the ongoing microbial activity and ultimately leads to destruction of soil fertility and productivity. Similar efforts for studying the deleterious effects of pesticides were highlighted by Diallo (1986), revealing that the toxicity of insecticides is mainly attributed to distortion of foliage necrosis and yellowing, thus causing a reduction in yield.

A pesticide residue analysis was performed by Baker (2002) to quantify differences between organic and chemically grown fruit and vegetable (fresh). The data collected on food residues from different markets that were conventionally grown, integrated pest management (IPM)-grown (NDR), and organically grown were compared using data reported from three different test programs. It was recorded that multiple pesticides are highest in conventionally grown and IPM samples when compared to organic cultivation.

Glover and Tetteh (2008) studied the increasing rates of pesticide application of lindane, undane, ditahne, and karate, (156.0, 244.0, and 312.0 g ha −1; (125.0, 187.5, and 250.0 g ha−1; 166.6, 209.8 , and 333.3 g ha−1), respectively on, okro, eggs, and tomatoes, to find out the advantages that are offered to a farmer by their use. It was seen that yields of garden eggs were reduced by the application of lindane. Doses higher than L20 were observed (i.e. 244 and 312 g ha−1) to affect the yield drastically, whereas the yields of okra were higher than the control at all levels. The application of unden had the optimum effect on garden egg yields followed by tomatoes and okro. Increasing rates of unden on okro did not have any significant effect. The results indicated that the pesticide application greatly influenced the fungal population (50–70% reduction) compared to the bacterial population in the soil (23.0–38.4% reduction). Okro yields were higher than the control at every lindane application. It can be concluded that pesticide application had a greater effect on fungal populations than on bacterial populations in the soil.

Abreu et al. in (2007) worked on anti-nutritional and toxic components of potato tubers. For this, a comparison of glycoalkaloids was carried out for organic and conventional potato tubers in Portugal. Although differences were observed for one potato variety, the other varieties’ glycoalkaloid levels were much higher in conventionally grown crops (79.5 mg/kg) than the those grown organically (44.6 mg/kg).

June 2009 (Source: The Organic Center, AAAS Session) saw the advent of a report about chemicals affecting the endocrine system, stating that there is evidence for altered health systems resulting in increased infertility, cancers, obesity, etc. (Source-Pediatrics, 2010).

In brief, the meta-analysis included 240 reports including 17 human studies, comparing organically and conventionally grown food, and reported that organic foods are considered safer and healthier than conventional foods (Beyond Pesticides, 2015).

26.3.9 Marketability, Consumer’s Perceptions, and Preferences

The CONDOR project was the first to examine attitudes and behavior in relation to both fresh and processed organic foods and to do so across a number of the EU member states. It involved the development of a theoretically based consumer decision-making model for the purchase of organic food and the testing of this model in eight EU member states. The study highlights consumer perceptions on theory of planned behavior, which was modified slightly for this project. According to this theory, consumer behavior is co-determined by: (a) the individual’s decisions as reflected in behavioral intentions; and (b) situational constraints and facilitators. Consumer intentions are co-determined by: (a) attitudes toward the behavior; (b) perceived social pressure; and (c) perceived control or self-efficacy. Finally, these three constructs are based on the person’s relevant beliefs and evaluations.

Consumer surveys have indicated that people believe organically grown foods are better in terms of safety, nutritional quality, and taste than their conventional counterparts (Hammitt 1990; Davies et al. 1995). Organic buyers display a different lifestyle pattern than do conventional buyers.

The taste factor of crops has not been taken into consideration, which generally affects consumer perception. During the 1990s, tomatoes with no taste were termed “water bombe” by the unsatisfied German consumer (Baldwin et al. 1988). The reason for these tasteless tomatoes was accredited to more attention being paid to parameters like yields, pest resistance, product stability, durability, and price, while the taste attribute was fully ignored.

A consumer with a preference toward “organic” products in supermarkets is usually viewing these products as organic commodities, without considering brands and packaging. “Organic commodities” are considered as products with better quality as these are produced in local and safe environments. In contrast to safe organic food, conventional foods are generally linked with negative properties.

The commercial production of fresh tomatoes has been seen in about 20 states on a large scale. The USDA 2012 Census of Agriculture recorded an approximately 10% reduction in tomato production with a 20% rise in the number of farms. The census data showed that the highest growth was in farms with 5-acre dimensions or less.

Comparing the era of 2011, the per capita consumption of tomatoes in the USA slightly decreased to 17.3 pounds per person from 17.9 pounds/person. The USDA Economic Research Service estimates depict the largest use of processed tomatoes to be in sauces (35%), followed by paste (18%), canned whole tomato products (17%), and lastly catsup and juice (15% each).

Sanjuan et al. (2003) investigated willingness of consumers to adopt an organic lifestyle, which generally includes various factors pertaining to natural food choice, a balanced life, a positive attitude toward health, and social improvement. The studies showed that the preference of consumers and their willingness to go for organic food ranged from 22% to 37% for vegetables.

Carroll et al. (2013) carried out an experiment regarding consumer choice and willingness to pay for a locally grown, safe organic food from five mid-Atlantic states. This study relied on a mail survey of consumers to determine preferences for organic food in markets and groceries.

Order of preferences in local and state program versions showed various differences. For the three largest states, Virginia, Pennsylvania, and Maryland, a local product was preferred. Overall, these findings form a basis for the increased interest in food products produced locally within the region and the expansion of such programs.

To maintain the good growth of a farmer, good markets promoting locally produced organic food with beneficial incentives need to be upgraded to provide novel ways of attracting customers.

According to recent research in Greece (Anastasiadis and Van Dam 2014), purchasers are basically attracted by sustainability concerns that include ecofriendly and natural modes of production and cultivation. The study also confirms initial findings (Essoussi and Zahaf 2008; Zanoli and Naspetti 2002) that emphasise the importance of health, which presents a real motivation for purchasing organic produce.

26.4 Recommendations and Future Directions

Steadily growing public concerns about soil health, crop quality, productivity, pesticide residues, food safety, security, environmental quality, and ground-water contamination call for an initial objective of comparing conventional and organic farming systems in accordance with the following factors:

  1. 1.

    The large prevalence of weed and unwanted pathogen populations.

  2. 2.

    The differences in soil properties

  3. 3.

    Yield parameters, growth, and health attributes.

  4. 4.

    Economically viable methods

Below are some of the researchable issues for future consideration:

The organic sector is moving forward to upgrade organic farming systems by developing seed and planting materials organically to eradicate the biggest problems regarding soil fertility. Pest and diseases can be accurately controlled in organic systems, but some other points need to be taken in to consideration:

  • The production of healthy seeds and nurseries, which is dependent on the various breeding programs.

  • The maintenance of lower disease pressure via the improvement and strengthening of organic cultural practices.

  • The development of varieties with increased tolerance against wide varieties of diseases and variable pathogens.

  • Increased focus on improving methods for a good seed and plant stock production.

  • The seed producers should have knowledge about selecting the best locations with lower disease pressure.

  • The seed health standards should be improved for fighting against a high risk of seed-borne diseases.

  • For the successful establishment of organic seed production all communication gaps should be resolved and a mutual commitment between the various groups from cultivation to production (farmers, traders, breeders, and government) needs to be made.

Conclusion

A major conclusion can be drawn in favor of going organic by highlighting various parameters including increasing soil health and protecting soil fertility from erosion via improved drainage systems. The new technological interventions in organic farming used to protect soil fertility include barrier crops, crop rotations, mulching, green manuring, application of on and off-farm inputs, and use of biodynamic preparations for insect pest and disease management. Organic farming methods rely on a high level of microbial activity in the soil and at the same time contribute increased abundance and diversity of those same beneficial soil microorganisms. Some of the benefits of this include: better uptake of minerals which enhances the nutrient supply, improvement in crop vigor, and reduced nutrient run-off.

Soil communities feed on organic matter in the soil while nutrients are made available to plants by those soil organisms that rely on them for their food and survival. The increased level of soil organic matter is also an indicator for rating a good soil, as it furnishes many important functions that are important to organic agricultural systems. Therefore, efforts should be made in the direction of developing methods to increase soil organic matter, which will serve to accomplish an important goal for organic farmers.