猪粪化肥配施对双季稻稻田土壤活性碳氮含量及水稻产量的影响

以湖南省长沙典型红壤性水稻土为对象,采用田间定位试验,设置了不施氮(CK)、常规氮肥减半(50%N)、常规全量氮肥(100%N)、猪粪替代50%氮肥(50%N+PM)四个氮肥处理,研究猪粪部分替代化学氮肥对双季稻田土壤活性碳氮含量和水稻产量的影响。2012年结果表明,在早稻整个生长期和晚稻孕穗期以前,50%N+PM与100%N处理相比,其对土壤NH4+-N含量无明显影响,而在晚稻完熟期,50%N+PM处理土壤NH4+-N含量增加了65%。50%N+PM处理在早稻移栽期、晚稻孕穗期、早稻晚稻乳熟期和完熟期较100%N处理显著提高了土壤可溶性有机氮(DON)含量,增幅在50%-102%之间。在整个水稻季,50%N+PM处理与100%N处理相比,提高了土壤微生物生物量碳(MBC)和微生物生物量氮(MBM)含量,提高幅度为21.5%-22.8%和5.3%-7.1%,而对水稻产量差异不显著,但明显高于50%N和CK处理。与CK处理相比,猪粪化肥配施和100%N处理的年产量分别提高了47.0%和32.9%。表明猪粪化肥合理配施可以维持水稻产量和土壤无机氮水平,同时可提高土壤微生物生物量碳和微生物生物量氮,改善土壤肥力。

Effects of combined applications of pig manure and chemical fertilizers on soil carbon and nitrogen fertility and gain yield in double-rice ecosystem

A field experiment was carried out in Hunan Province in 2012. Four nitrogen treatments: CK (non-fertilized), 50%N (50% chemical N fertilizer), 100%N (100% chemical N fertilizer), and 50%N + PM (pig manurewere) set up to study the effects of combined applications of pig manure and chemical fertilizers on soil carbon and nitrogen fertility and rice yields in a typical paddy field with double-rice cropping. The results showed that soil ammonium-N (NH4+-N) content in the 50%N+PM treatment was not significantly different from that in the 100%N treatment during the early rice season and the period before booting stage in the late rice season, but was significantly higher than the 100%N treatment by about 65% in the full-ripe stage of later rice. Soil dissolvable organic N (DON) content in the 50%N+PM treatment was significantly higher than that in the 100%N treatment by 50%-102% in the transplanting stage, tillering stage and milk-ripe stage in the early rice season and in the booting stage, milk-ripe stage and full-ripe stage in the late rice season. Soil microbial biomass carbon and nitrogen (MBC and MBN) amounts in the 50%N+PM treatment were also higher than those in the 100%N treatment by 21.5%-22.8% and 5.3%-7.1% respectively. The rice grain yields in the 50%N+PM and 100%N treatments showed no significant difference, but were significantly higher than those in the CK and 50%N treatments. Compared with the CK treatment, the 50%N + PM and 100%N treatments had their annual grain yields increased by 47.0% and 32.9%, respectively. Our results indicated that the combined application of pig manure and chemical fertilizers at an optimal ratio can maintain soil mineral N content and rice grain yield and simultaneously increase soil MBC and MBN amounts, and therefore it improves soil fertility.