| This research analyzed the light intensity distribution and its influence on photosynthesis and transpiration of inter-crop leaf,transpiration of trees,soil water distribution,soil nutrients distribution and changes of plant nutrients in apricot-salvia and apricot-alfalfa agroforestry systems in hilly region of Taihang Mountain.This study provided scientific theoretical basis of agroforestry systems for the sustainable management in order to improve management in this area.The main results are as follows:(1)Compared with monoculture systems,there is a little effect on the stock circumference,new branches and yield of apricot in apricot-salvia and apricot-alfalfa intercropping system,however,the height,root diameter and biomass of alfalfa and Salvia miltiorrhiza reduced in intercropping system.The smaller of the density of apricot and the closer of the distance between the crop the tree lines is,the greater of the degree low.(2)The light intensity had characteristics of temporal and spatial variation.In the horizontal direction, for the daily average light intensity was descending from the middle of the tree line to the close lines, that the lower of daily average light intensity;and the smaller of spacing,and the lower of daily average light intensity,for example,the average of daily light intensity of 3m×4m system was 14.4 percent lower than 3m×8m system.Furthermore,the light intensity of the east of trees was reach peak earlier than the west.Also,the distraction of light influence the photosynthesis and transpiration rate of the canopy of alfalfa and Salvia,the lower of the intensity of light,the smaller of the photosynthesis and transpiration rate.(3) Compared with monoculture systems,there is a little effect on the transpiration of apricot in agroforestry systems.For the impact of changes in the weather,rate of transpiration of apricot changed diurnally and seasonally.However,the water compound of salvia and alfalfa reduced under the intercropping pattern compared with single systems of salvia or alfalfa.In 2005 and 2006,water compound of salvia decreased about 13.1%and 11.2%in the whole growing stage,which did of alfalfa about 12.21%and 12.34%,Respectively.(4) The tendency of soil water contents within 0～60cm soil layer of the single and agroforestry system is similar with the same spatial changes characteristics.But the grads change of soil water contents in agroforestry system is smaller than in monoculture systems and the soil water content is comparatively steady in profile.From the direction of changes in soil moisture levels,water content of the 0-60cm soil layer in the soil profile attained maximum in the middle line and weakened when there is a distance from middle;from changes of soil moisture in the vertical direction,when the closer of the distance from recent tree line in the direction,the more active of changes in vertical soil moisture.The water content is higher in the upper.(5)The soil physical properties improved in agroforestry systems after intercropped salvia and alfalfa 2 years,with the soil bulk density decreased the stability of infiltration rate and total porosity increased.In vertical direction,the intercropping Salvia would improve the soil bulk density,stability,infiltration rate and total porosity of 20-40cm layer obvious,as well as intercropping alfalfa would influence 0-40cm layer;in the horizontal direction,the degree of improvement descending from the middle line to the close from the tree line.(6)There were distribution characteristics of spatial variation for N,P,K,and organic matter of soil.In the horizontal,total N,total P,total K and available N,available P,available K reached maximum in the middle but decreased when there was a little distance between the tree zone and middle zone,but organic matter content was lowest of the middle zone;in the vertical direction,total N,total P,the total K,organic matter and available P,available content was reduced with increasing soil depth,quick N reached peak in the 20-40cm of soil layer.(7)From the preliminary findings of the study,there was a little impact on apricot under the agroforestry systems,while intercropping can improve soil moisture and soil nutrients.Therefore,for using of resources rationally,developing fruit-grass,fruit-medicines intercropping systems appropriately in this region is feasible.However,it need develop appropriate management techniques in order to promote the growth of inter-crops,such as reducing pruning the shade of trees of inter-crops,ensuring soil moisture security during the rainy season,combing trenching and cutting root with fertilizer,to enhance the productivity of complex models,to achieve sustainable management of agroforestry systems in this area. |
