玉米大豆间作条件下大豆固氮及其效益的研究

本文在三种施氮水平上对玉米大豆间作条件下大豆的根瘤形成及固氮等问题进行了研究。结果表明:与单作未施肥大豆相比,三种不同施肥水平上间作大豆的根瘤形成及固氮能力均有所降低,氮肥水平越高,下降越严重;间作条件下,大豆固氮活性的降低大于根瘤数和根瘤重,同样肥力水平下,玉米间作大豆的后茬作物产量显著低于单作大豆的后茬作物产量,而与单作玉米的后茬产量差异不大。与休闲地相比,无论大豆单作还是间作,其后茬产量都显著降低。因此种植大豆不是培肥地力而是消耗土壤肥力。间作大豆对玉米无促进作用,反而使玉米产量下降,对玉米植株含氮量影响不大。间作后作物总产量降低,但蛋白质产量和经济收益明显增加。

A Study on the Soybean Nitrogen Fixation and its Gains Under Maize-Soybean intercropping

Investigation on nodulation and fixation of soybeans under soybean-maizeintercropping were carried out at three N supply levels.The results showed thatnodulation and nitrogen fixation of soybeans in intercropping at three N supplylevels were all decreased as compared with those in a soybean monocrop,andthe more nitrogen supply,the more seriously the ability of nitrogen fixationdecreased.Under the condition of intercropping,the decrease of nitrogen fixa-tion activity of soybean is more serious than that of weight and number of no-dules.At the same N level the grain yield of subsequent crop wheat from inter-crop were significantly less than that from sole cropping soybean,but only li-ttle difference was found about subsequent wheat grain yield between intercropp-ing and maize mono-cropping.After soybean cropping,the soil fertility wasreduced significantily,whether mono-soybean or soybean-maize intercropping.Maize grain yield was decreased under intercropping conditions as compared withmono-maize planting,but there was only little difference about N content ofmaize plant between the two cropping patterns.After intercrop planting,thetotal grain yield was reduced,but total protein yield and economical gains wasincreased significantly.