玉米-紫花苜蓿间作模式与效应研究

A study on the pattern and effect of Zea mays intercropping with Medicago sativa

以玉米和紫花苜蓿间作系统为研究对象,研究了不同间作模式和不同减氮水平下的光照强度、透光率、土壤养分含量、玉米产量、苜蓿产量和单位面积纯收益变化规律。结果表明,随着玉米大行距的加大,玉米行间和苜蓿带与玉米带间隔中部、底部的光照强度和透光率均表现增大趋势,除T4处理外,其他处理的玉米行间中部、底部的光照强度和透光率均高于对照CK。间作处理的有机质、有机氮、速效氮较对照均成增加趋势,而且这种趋势随着间作时间的延长越发明显,土壤有机质、有机氮、速效氮含量随玉米大行距的加大均成增加趋势。在保持单位面积株数相同的情况下,3个试验年份玉米籽粒产量均以T2处理最高,除T4处理玉米籽粒产量低于对照外,其他处理产量均高于对照,苜蓿产量随玉米大行距的加大均成增加趋势;3个试验年份单位面积纯收益均以T3处理最高,所有间作处理单位面积纯收益均高于对照。减氮均不同程度地造成了玉米减产,但随着间作时间的延长减氮所造成的减产幅度逐渐降低,到试验第3年,R1和R2处理的玉米产量与CK相比没有显著性差异(P>0.05);试验第3年R1和R2处理的单位面积纯收益均高于CK,但差异不显著(P>0.05)。

The legume/cereal intercropping system,supplying the world with most of the grain and proteins,is one of the most successfully farming systems for small-holder farmers.It is undoubtedly a sustainable farming system from both resources use and environmental friendly aspects as the nitrogen fixed by legumes sustains this system.Internationally,research effort has been focused on biological nitrogen fixation in legume/graminaceae systems due to environmental problems and energy crisis caused by irrational N fertilizer use.The change of light intensity,light transmittance,soil nutrients,corn grain yield,alfalfa yield and income of the system of corn intercropping with alfalfa were studied.Light intensity and light transmittance of different parts increased as the row space changed from narrow to wide,and in all treatments they were higher than in the CK except in T4.The contents of organic matter,organic nitrogen and available nitrogen of intercropping treatments displayed an increasing trend compared with those of the CK,and the trends became increasingly obvious with successive intercropping years.The contents increased with row space.With the same corn number per hectare,the maximum corn grain yield was achieved in T2 treatment for 3 years,and in all treatments it was higher than in the CK except for T4.Alfalfa yield increased with row space.Reduced N use resulted in reduced maize yield of various degrees,and yield declined with intercropping year,but there was no significant difference of yield between R1,R2,and CK in 2008.