Primary limitation on vegetation productivity shifts from precipitation in dry years to nitrogen in wet years in a degraded arid steppe of Inner Mongolia, northern China
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Arid steppes in northern China have degraded severely in recent decades due to frequent human activities, resulting in poor soil quality and thus low productivity. The objective of the current study was to investigate whether nitrogen addition was a useful approach to improve productivity of these degraded steppes in Inner Mongolia.
Materials and methods
In the current study, severely degraded arid steppe was fenced in June 2014 and then fertilized for consecutive 3 years, 2014, 2015, and 2016. There were four nitrogen fertilization rates, 0, 50, 100, and 150 kg N ha−1, and two phosphorus rates, 0 and 60 kg P2O5 ha−1. Each treatment replicated three times, with each plot size reaching 400 m2 (20 m × 20 m). The annual precipitation in 2014 and 2016 were 255 and 309 mm (dry years), respectively, lower than that (412 mm) in 2015 (wet year).
Results and discussion
The results indicated that aboveground biomass in wet years was significantly higher than that in dry years, suggesting that water is the most important limiting factor influencing steppe productivity. Plant nitrogen concentration in Stipa krylovii (dominant species) was positively correlated with the concentrations of soil available nitrogen and nitrogen use efficiency (NUE), confirming that the plant adsorbed more nitrogen under fertilization and thus increasing the NUE. The NUE and water use efficiency (WUE) in wet year were higher than those in dry years and a positive correlation was also observed between WUE and NUE, confirming that the NUE was relied mainly on precipitation.
Nitrogen fertilization was effective in increasing grassland production in wet years but not in dry years, suggesting that the primary limitation on grassland productivity in this ecosystem might shift from precipitation in dry years to nitrogen in wet years. Higher NUE could be obtained under low nitrogen rates in wet years. Therefore, in degraded arid steppe, low nitrogen rate (50 kg N ha−1) was recommended in wet years to improve steppe productivity.
KeywordsFertilization Grassland Nitrogen use efficiency (NUE) Water use efficiency (WUE) Yields
The work was supported by the National Key Basic Research Program of China (2014CB138806) and National Natural Science Foundation of China (31670407).
- Austin AT (2002) Differential effects of precipitation on production and decomposition along a rainfall gradient in Hawaii. Ecology 83:328–338Google Scholar
- Bao SD (2005) Agricultural chemical analysis of soil. China Agriculture Press, BeijingGoogle Scholar
- Brouwer R (1983) Functional equilibrium: sense or nonsense? Neth J Agric Sci 31:335–348Google Scholar
- Comakli B, Mentese O, Koc A (2005) Nitrogen fertilizing and pre-anthesis cutting stage improve dry matter production, protein content and botanical composition in meadows. Acta Agr Scand 55:125–130Google Scholar
- Hati KM, Swarup A, Dwivedi AK, Misra AK, Bandyopadhyay KK (2007) Changes in soil physical properties and organic carbon status at the topsoil horizon of a vertisol of central India after 28 years of continuous cropping, fertilization and manuring. Agric Ecosyst Environ 119:127–134CrossRefGoogle Scholar
- He J (2012) Precipitation variation characteristics of Xilinhot city for 50 years. Chin Sci Bull 28:271–278Google Scholar
- Hooper DU, Johnson L (1999) Nitrogen limitation in dryland ecosystems: responses to geographical and temporal variation in precipitation. Biogeochemistry 46:247–293Google Scholar
- Jobbágy EG, Sala OE, Paruelo JM (2002) Patterns and controls of primary production in the Patagonian steppe: a remote sensing approach. Ecology 83:7–319Google Scholar
- Liu LJ, Wei XU, Tang C, Wang ZQ, Yang JC (2005) Effect of indigenous nitrogen supply of soil on the grain yield and fertilizer-N use efficiency in rice. Rice Sci 12:267–274Google Scholar
- Rathore VS, Nathawat NS, Bhardwaj S, Sasidharan RP, Yadav BM, Kumar M, Santra P, Yadava ND, Yadav OP (2017) Yield, water and nitrogen use efficiencies of sprinkler irrigated wheat grown under different irrigation and nitrogen levels in an arid region. Agr Water Manage 187:232–245CrossRefGoogle Scholar
- Vakhmistrov DB, Vorontsov VA (1997) Selective nutrient uptake by plants is not aimed at providing superior growth. Russ J Plant Physiol 44:349–356Google Scholar
- Wang B, Liu W, Dang T (2011) Effects of phosphorus on crop water and nitrogen use efficiency under different precipitation year in dryland. ISWREP 2011 - Proceedings of 2011 International Symposium on Water Resource and Environ Prot. 3. https://doi.org/10.1109/ISWREP.2011.5893679
- Yang W, He M, Wang Y, Wang X, Zhang B, Wu C (2005) Effect of controlled-release urea combined application with urea on nitrogen utilization efficiency of winter wheat. Plant Nutr Fert Sci 11Google Scholar
- Zhang H, Khan A, Tan DKY, Luo H (2017) Rational water and nitrogen management improves root growth, increases yield and maintains water use efficiency of cotton under mulch drip irrigation. Frontier Plant Sci 8Google Scholar