Agroforestry Paradigm Concerning Non-Irrigated Apple Orchards in Tableland Areas of the Loess Plateau
WANG Han-sheng;Institute of Soil and Water Conservation,Northwest A&F University;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources;
Intercropping in non-irrigated apple orchards,especially before prominent fruit production,is an agroforestry style fairly prevailing in tableland areas of the Loess Plateau owing to the large-scale expansion of apple cultivation. In order to emphatically take apple trees as principal components in orchard management and set up favorable intercropping system,the overall investigation of intercropping types was carried out in the typical tableland areas in the boundary of Shaanxi Province and Gansu Province,and in some representatively selected orchards,the height,basal diameter,branching activity of apple trees and the soil moisture of 3-meter-deep profiles under the growth influence of the intercrops were comparatively determined with control as well. Through those the intercropping principles and the suitability of related intercropping practices were analyzed. Meanwhile the intercropping normalization operation was dealt with out of both the actual situation and the growth process of apple trees. The results indicated that based on the growth change of fruit trees,3 different intercropping periods were discriminated as follows: early young stage,late young stage,and adult stage. From the beginning of the late young stage on,it became strict to select intercrops,which were strikingly required to possess the characteristic of shade tolerance. Dwarf crops with shallow roots were obviously superior in time and space. The growth of fruit trees under watermelon or sweet potato intercropping was better than under wheat or maize intercropping. Among the high-stalk crops with deep roots(wheat,maize,rape,and millet),the inhibition effect of maize on the growth of fruittrees was lower. Wheat intercropping in just keeping empty the ground patch around each fruit tree resulted in the nobranching proportion of about 65%. There were the differences of water consumptivity between different intercrops,of which the water consumption depth of wheat was down to 3 m,maize 1 m,soybean 0. 4 m,and white clover 1. 6 m. Soil water consumption within the year didn't obtain rehabilitative offset in wheat or white clover growing for 5-9 years old. The competitive relationships of intercrops with fruit trees can be shown according to the growth of fruit trees and the soil moisture consumption by intercrops. The underground competition of dwarf crops with shallow roots is relatively weak,but white clover is an exception in particular,its competition shouldn' t be ignored. Ecological niche separation is the key to intercropping,especially for high-stalk crops with deep roots and shallow-root crops which will have some inevitable root overlap to fruit trees. It is inadvisable to implement double cropping or continuous cropping after wheat harvest. It is necessary to plough as soon as early for white clover in decline. Intercropping proceeding would need to pay attention to soil fertility maintaining crops,and to comprehensively take account of such aspects as ecological niche separation,rotation cropping,proper crop yield,fruit tree decline,etc.
【Fund】： 中国科学院知识创新工程重要方向(KZCX2-YW-441 KZCX2-YW-149);; 国家自然科学基金(41271526)
【CateGory Index】： S344;S661.1
【CateGory Index】： S344;S661.1