黄绵土长期定位试验中硝态氮剖面分布特征

Effect of Long-term Located Fertilization on NO_3^--N Accumulation in the Profile of Loessial Soil

对1982年建立的长期肥料定位试验的土壤剖面硝态氮含量变化进行分析。结果表明,经25a种植冬小麦施用不同肥料后,土壤0～400cm土层硝态氮含量差异显著,施N、NP、NPK在200cm出现累积峰,各处理在300cm以下硝态氮含量显著减少(低于1.0mg/kg)。对于CK、和单施P处理的100cm以下土壤因长期没有N肥的补给,作物的长期吸收利用,而趋于耗竭(低于1.0mg/kg);单施N和NP配施处理0～400cm土壤剖面中的氮残留量高达1 323.3kg/hm2,是不施肥的23.3倍,NPK配施也达655.9kg/hm2,是不施肥的11.1倍;M处理的残留量维持在1 018.6～1 753.1kg/hm2左右,与化肥处理相比残留量显著增加,M处理比CK处理、NM处理比N处理、NPM处理比NP处理和NPKM处理比NPK处理分别增加了93.1%、21.1%、32.5%和83.3%。单施N的硝态氮年残留率最大,相当于施肥量的48.6%;NP配施残留率33.6%,NPK为21.3%。M、NM、NPM和NPKM处理的硝态氮残留率分别为2.6%、33.2%、25.2%和22.8%。平衡施肥能显著减少硝态氮含量,相同施氮水平下,配施磷肥、钾肥、有机肥的硝态氮残留率显著减少。

A 25 years fertilization experiment was carried out with wheat-grown Loessial soil in North China,and the profile of nitric nitrogen content in soil was analyzed.The results showed that there is significant differences on NO3——N contents in the 0-400 cm soil layer,after 25 years cultivation of the winter wheat.It showed an peak accumulation at 200 cm soil layer,and reduced significantly under 300 cm soil layer,（less than 1.0 mg/kg） in N,NP and NPK treatment.When organic fertilizer supplied only,the accumulation of NO3--N increased in the surface of soil and tended to exhaust under the 120 cm soil layer.The NO3--N content in N and NP treatment was more than 1323.3kg/hm2,about 23.3 times of that in CK treatment,and 655.9 kg/hm2 and about 11.1 times in NPK treatment.The NO3--N in manure treatment was about 1 028.6 to 1 753.1 kg/hm2,higher than in chemical fertilizer treatment,significantly.NO3--N accumulated rate increased 93%,21.1%,32.5% and 83.3% in the comparison of M to CK,NM to N,NPM to NP and NPKM to NPK,respectively.The NO3--N accumulated rate in N,NP and NPK treatment is 48.6%,33.6% and 21.3% respectively,and about 2.6%,33.2%,25.2% and 22.8% in M,NM,NPM and NPKM treatment,respectively.The combined application of NP,K and manure,with the same level of applying nitrogenous,can reduced the nitrate content significantly.