稻田养分循环利用模式的研究

A STUDY ON NUTRIENT CYCLING AND UTILIZING PATTERNS IN PADDY FIELD

研究了稻田养分利用的３种模式，证明在本实验条件下：单施化肥每千克养分增产稻谷６．０９ｋｇ，产投比１．７９：１，且不利于土壤生态的改善；种植冬季绿肥紫云英——早稻草还田，配施适量化肥，每千克养分增产稻谷６．１８ｋｇ，产投比１．８２：１，节约近半数化肥，土壤肥力有所提高，有一定的生态效益；冬季绿肥肥饲兼用——猪粪尿沼气发酵——沼肥还田，节约２／３的化肥，每千克养分增产稻谷６．６１ｋｇ，同时每７４．３千克紫云英鲜草经青贮饲猪，可增猪重１ｋｇ。每千克紫云英干物间接产沼气０．４ｍ￣３，沼肥回收的紫云英氮、磷、钾分别为３２．８％，７２．９％，３９．１％，全程产投比约为４：１，是一个高功能、高效益的养分循环利用模式。

This paper deals with three patterns of nutrient utilization in rice field.Under the experi-mental condition,in the pattern of applying only chemical fertilizer one kilogram(kg)of nutri-ents added 6.09 kg of rice grain to the output.The ratio of output to input was 1.79:1.Thispattern was not beneficial to the improvement of soil ecology. In the pattern of growing wintergreen manure crop- milk vetch(Astragalus sinicus L. )and returning the early rice straw tothe field combined with proper amount of chemical fertitizers,one kg of nutrients added 6.18kg of rice grain to the output.The ratio of output to input was 1.82: 1.This pattern savedalmost half of the amount of chemical fertilizers,increased soil fertility and has certain ecologialefficiency. In the pattern of concurrent using of winter green manure crop both as fertilizer andas feed-fermenting pig manure to generate biogas-applying the biogas fertilizer(biogas fer-mented manure)to the field,one kg of nutrient added 6.61 kg of rice grain to the output and2/3 of chemical fertilizers was saved.Meanwhile every 74.3 kg of ensilaged milk vetchused asfeed added one kg of pig weight,and one kg of dry milk vetch generated 0.4m￣3 of biogas indi-rectly, the N,P and K reclaimed from the biogas fertilizer were 32.8%, 72.9%and 39.1%respectively. The overall ratio of output to input was 4:1, making a nutrient cycling and uti-lizing pattern with high performance and high efficiency.