新垦赤红壤不同轮作的养分变化

五年的研究结果是:赤红壤耕垦之后只要采取合理的轮作和结合适当的秸秆返回措施,它的肥力就可以得到保持,而且还可以获得显著提高。在四种轮作形式中,效果最明显的为1:1,它的土壤有机质、全量N、P、K含量比轮作前分别提高了L 22、1.84、2.27和0.06倍1:2和2:1的效果较差,分别提高了0.57、0.83、2.08、0.39倍和1.02、0.91、1.46、-0.07倍,0:1的由于没有轮作,加上每年把长好的草皮铲走,导致了土壤有机质、全氮量反而比轮作前下降了6.5％和25.0％。随着轮作土壤养分的提高,土壤物理和微生物状况也获得了改善。

NUTRIENT CHANGES IN NEWLY RECLATMED LATORED SOILS UNDER DIFFERENT ROTATION OF CROPS

Four different rotation trials in proportion of leguminous and nonleguminous crops as 1 : 1, 1 : 2, 2 : 1 and 0 : 1 on latored soils and the study on organic matter and nutrient changes in the soils of the test plots were engaged from 1985 to 1989.The results are as follows:(1) In the high-temperature and rainy region, decomposition of soil organic matter and the consumption of nutrients are rapid. The rotation of crops and returning of straws and stalks to field may maintain and improve the soil fertility.(2) The ratios of input to output of four rotation systems were 1 : 1>1 : 2>2 : 1>0 : 1, that is 1 : 8.97, 1 : 7.80, 1 : 7.08 and 1 : 7.07 respectively.(3) Except the 0:1, the carbon-returning amounts from the straws and stalks to soil after five years of rotation are 13906.5, 7818.0 and 7429. 5 kg/hm~2 and the organic matter content has increased by 84.9%, 106.5% and 86.2% respectively. It shows a similar tendency for other soil nutrients, but the 1 : 1 and 1 : 2 are better than the 2 : 1 and 0 : 1 in harvest and nutrient increase.