长期施用有机和无机肥对潮土氮素平衡与去向的影响

通过13年26季不同施肥方式对潮土土壤氮素平衡及去向进行定位监测的结果表明,不施氮肥土壤平均每年接受外源氮为N.23～24.kg/hm2,小麦和玉米带走N.82～88.kg/hm2,亏缺N.58.6～63.7.kg/hm2;各施氮肥处理平均每年实际盈余N.238.6～418.kg/hm2,其盈余多少顺序为1.5MNPKNNKMNPK(2)MNPKNPKNPSNPK。N、NK处理土壤接受外源氮N为4881和4876.kg/hm2,其中14.1%～20.7%被作物吸收利用,17.2%和5.2%残留在土壤,64%和72%损失;NP、NPK处理氮素去向基本一致,48%被作物利用,9.7%的残留在土壤中,55%损失;有机肥处理(MNPK)的氮素利用率、残留率和损失率分别为44.3%、23%和42%;有机肥用量增加,氮素利用率降低,损失率增加;秸秆还田(SNPK)氮素利用率最高,为51%;NK处理氮素损失最大。

Effect of long term fertilizers and organic inputs on balance and fate of nitrogen in fluvo-aquic soil

Long-term fertilization experiments started in 1990 were conducted to evaluate the influences of different fertilization,on yields,soil fertility,nutrient balance and use efficiency in winter wheat-summer maize and winter wheat-soybean rotations in a fluvo-aquic soil in the research farm of Henan Academy of Agricultural Sciences.The results showed that treatments no N addressed received exogenous N 23—24 kg/ha from rainfall and irrigation annually.However,the removal from straw and grain of wheat and maize at harvest exported around N 82—88 kg/ha.Therefore,it resulted in a N deficit being 58.6—63.7 kg/ha annually on no N addressed treatment.N application caused N surplus ranged from 238.6 to 418 kg/ha in 0—40 cm layer,with the order being 1.5MNPK>N>NK>MNPK(2)>MNPK>NPK>NP>SNPK.Among 4881 and 4876 kg/ha exogenous N in N and NK treatment, N recovery,residue N and N lose rate(accounted) for 14.1% and 20.7%,5.2% and 17.2%,45% and 66.7%,respectively.The fate of nitrogen in NP and NPK treatments was similar with the recovery rate,residue N and N loss rate being 48%,9.7% and 55% respectively;while for MNPK,the recovery rate,residue N and N loss rate was 44.3%,23% and 42% respectively;With the(increase) of manure application rate,N recovery rate declined and loss rate enhanced.The highest N recovery rate was(observed) in SNPK,and the lowest recovery rate was found in N treatment which was 2.6 times lower;N loss rate in NK treatment was the highest and MNPK had the lowest N loss rate which was almost 3.5 times less than NK.