Manipulating the Crop Environment

Abstract

Windbreaks are structures that reduce wind speed and may affect turbulence in the protected zone. The maximum efficiency is obtained with windbreaks of medium porosity that reduce wind speed up to a distance 20–25 times their height. In the area protected by a windbreak temperature oscillations are larger, which in some areas may increase frost risk and dew deposition.

Soil temperature can be modified by changing its exposure to radiation, by artificial heating or by mulching. Mulches can be natural (e.g. crop residues) or artificial, most notably plastic films. Canopy temperature can be reduced by wetting with sprinklers although it is only effective with high VPD and implies excessive water use. Simple models of the energy balance may be applied to calculate the minimum and the maximum crop temperature. Additional environmental control may be performed with row covers and greenhouses that create a warmer wind-protected environment and are increasingly popular in horticultural production.