有机肥部分替代化肥对滴灌棉田氮素转化及不同形态氮含量的影响

Effects of using organic fertilizer as partial substitution for chemical fertilizer on soil nitrogen transformation and amount of different nitrogen forms in drip irrigation

在滴灌条件下,采用连续3年定位增施有机肥小区试验,研究了不同有机无机肥配比对滴灌棉田土壤铵态氮、硝态氮、微生物量氮、全氮以及土壤矿化和硝化特性的影响,旨在明确滴灌棉田增施有机肥条件下土壤氮素转化与各形态氮素特征。结果表明,增施有机肥各处理均可显著增加土壤NH4^＋-N和NO3^- -N含量（P〈0.05）,且明显增加NH4^＋-N占总氮（TN）比例。在各施肥处理中,以配施6000 kg·hm^-2生物有机肥处理（60%CF＋BF2）的矿质氮含量最高;3年连续增施有机肥3000-6000 kg·hm^-2可明显增加滴灌棉田全氮和微生物量氮含量（P〈0.05）,其中生物有机肥（CF＋BF）对提高微生物量氮（MBN）/TN的效果显著,其土壤全氮分别比对照（CK）和单施化肥处理（CF）提高了24.7%-37.1%和13.3%-24.5%,微生物量氮分别增加53.8%-98.5%和32.2%-70.5%。有机无机肥配施可明显提高土壤硝化势和矿化能力。土壤增施3000-6000 kg·hm^-2有机肥对促进滴灌棉田氮素转化,调节不同形态氮素比例及提高氮素肥力有显著效应。

In order to elucidate the effects of organic fertilizer amendment on soil nitrogen transformation and the amounts of different form of soil N,a three- year location trail was fulfilled in calcareous soil under dip irrigated cotton field,soil mineral N concentration（ NH＋4,NO-3）,soil microbial N biomass as well as soil total N content were determined. The treatments contain CK,CF（ N 300 kg·hm^-2,P2O590 kg·hm^-2,K2O 60 kg·hm^-2） and different types（ cattle manure and Bio- organic fertilizer） and levels（ 3 000 kg·hm^-2and 6000 kg·hm^-2） of organic material combined with 60%（ N 180 kg·hm^-2,P2O554 kg·hm^-2,K2O 36 kg · hm^-2） or 80%（ N 240 kg·hm^-2,P2O572 kg · hm^-2,K2O 48 kg · hm^-2）NPK chemical fertilizer. There was a significant influence of organic fertilizer amendment on improving soil NH＋4- N and NO-3- N concentration（ P 〈0. 05） as well as increasing the ratio of soil NH＋4to soil total N. The highest soil mineral N was obtained in 60% CF ＋ BF2 treatment. Soil total N and soil microbial N were significantly increased after the continuous 3- year organic fertilizer application. Compared with CK and CF, soil TN content increased by 24. 7% - 37. 1% and 13. 3% -24. 5%,meanwhile,soil MBN increased by 53. 8% - 98. 5% and 32. 2% - 70. 5% respectively,with different treatments of organic fertilize supply. Moreover,bio-organic fertilizer treatment（ CF ＋ BF） had an obvious role on enhancing the proportion of MBN / TN,and organic fertilizer combined with chemical fertilizer improved soil nitrification potential and soil mineralization capacity. In conclusion,there was an significant effect of 3 000 - 6 000 kg·hm^-2organic fertilizer application on promoting soil nitrogen transformation,improving soil N fertility and optimizing the ratio of different forms of soil N under drip irrigated cotton field.