Abstract:

Intercropping has been studied and practiced widely for crop production, but it has seldom studied in the forage production. In this paper, intercropping system of different silage maize cultivars and alfalfa was studied in regard to physiological ecology of the system, yield and quality of products. Results showed that magrginal utility of silage maize was remarkable, and it changed with silage maize cultivars and growth stage. As compared with monocropping of silage maize, at male tatrad, light intensity and light transmission of intercropping silage maize was increased by 15.3%－88.1% and 15.1%－89.0% respectively at bottom of plants population, and 52.1%－74.1% and 51.2%－73.0% at middle layer of plant population; average light transmission for whole growth stage was increased by 49.5%－62.1% at bottom, and 40.7%－56.6% for middle part; average temperature of five centimeters soil layer at whole growth stage increased by 1.0%－1.8%. At the harvest period, plant height, stalk thickness and green leaf area of cultivars Keduo 4, Keduo 8, Keqing 1 in intercropping system were 2.3%－20.9%,0.4%－7.6% and 2.2%－19.6% greater than those for monocropping. Crude protein and crude fat contents in plant intercropping system were increased by 30.8%－59.1% and 99.4%－137.5% respectively compared with those for monocropping maize. The yields of green forage and hey for intercropping system were decreased by 22.7%－32.3% and 17.6%－28.2% as compared with monocropping maize, and increased by 156.7%－202.4% and 176.5%－197.5% as compared with monocropping alfalfa. Crude protein and crude fat contents, green forage and hey yields of alfalfa in intercropping system were slightly decreased at early flowering stage, but there were not significant difference between two cropping systems. Integrated analysis indicates that intercropping system can take advantage of light, temperature resources of local fields sufficiently. In addition, alfalfa is perennial legume, which can cover the fields, fix and fertilize soil, therefore protect soil from wind erosion. The harvest of alfalfa from May to June next year not only solves the problem of forage shortage for livestock husbandry in Inner Mongolia but also provide bigger space for the growth of intercropping silage maize.

Key words: Silage maize, Alfalfa, Intercropping, Illumination intensity