离树间距对间作苜蓿土壤理化性质及产量的影响

Effects of Distance from Tree Line on Soil Physicochemical Properties Along with Alfalfa Yield in Jujube and Alfalfa Intercropping System

通过大田试验,设置M1、M2、M3三种红枣-苜蓿间作模式,分别距离红枣树0.5 m、1 m、1.5 m处种植苜蓿,以苜蓿单作AM为对照,研究不同离树间距对间作苜蓿土壤理化性质及苜蓿产量的影响。结果表明:在枣苜间作条件下,土壤含水量总体表现出"先下降,后上升,再下降"的变化趋势,不同时期的土壤含水量M1>M2>M3;土壤容重和土壤紧实度在M3间距下最小;AM处理下土壤碱解氮含量最高;土壤速效磷M2>M3>M1;苜蓿产量从总体来看,第一茬比第二茬高约60%;苜蓿全年总产量在M2间距下最高。M3间距理化性质优,对土壤改善效果明显,M2间距下苜蓿产量最高;但M2理化性质与M3无显著差异,而M2产量显著高于M3。以上分析表明:枣苜间作模式有利于提高枣园的综合经济效益,且适宜的间距可协调两种作物间水肥的竞争关系。M2(距红枣1 m)是本试验中最适宜的种植间距。

Through the field experiments and setting three jujube-alfalfa intercropping models(M1, M2 and M3), the alfalfa was planted respectively at distances of 0.5 m, 1 m and 1.5 m from jujube trees, with taking alfalfa only(AM)as the comparing model, to study the effects of different distance between alfafa and trees on physical and chemical properties of soil and alfalfa yield of intercropping alfalfa. The results illustrated that under the conditions of jujube alfafa intercropping, the soil water content showed the trend of"first decreasing, then increasing, then decreasing". The soil water content was M1>M2>M3 in different stages. Soil bulk density and soil compactness are the smallest at the distance of M3. Soil alkali-hydrolyzable nitrogen content was the highest at AM. Soil available phosphorus M2>M3>M1;As a whole, the yield of alfalfa was 60% higher at the first crop than at the second. The total annual output of alfalfa was the highest under the M2 interval. The physical and chemical properties of M3 spacing were excellent, and the soil improvement effect was obvious. The yield of alfalfa was the highest under M2 spacing. However, there was no significant difference in physical and chemical properties between M2 and M3, while M2 yield was significantly higher than M3. The above analysis indicated that the mode of intercropping was beneficial to improve the comprehensive economic benefit of jujube orchard, and the suitable spacing could coordinate the competition of water and fertilizer between the two crops. M2(1 m apart from jujube)was the most appropriate planting spacing in this experiment.