The Investigation on Microclimatology of Agroforestry System in China

Agroforestry system or farm forestry is a production technique or method that combines agriculture and forestry to fully utilising the natural resources of sunlight,temperature and water.The investigation on the survey of the agroforestry systems microclimate in China since 1990′s was summarized.The characteristics of agroforestry systems microclimate are:(1)Component values of heat balance are positive in day time but negative at night.Among all component values of heat balance,the latent heat flux occupies the highest proportion from net radiation,both turbulence heat flux and soil heat flux occupy lower.(2)With the increase of plant coverage in agroforestry ecosystem,the net radiation,the relative intensity of illumination,temperature differentiation between day and night,and wind speed decrease,but air humidity increases.(3)With the increase of soil depth in the agroforestry ecosystem,the amplitude of temperature decreases in accordance with geometric series and the phase of temperature trailed in accordance with isogap series.The temperature gradience variation of soil are similar as the variety character of soil temperature.Knowledge on the characteristics of microclimate in the agroforestry systems is help ful for rational selecting plant coverage,tree height and canopy structure of trees in agroforestry systems.The study is favourable for maintaining the dynamic balance and increasing the comprehensive benefits of the systems.