长期调控施肥对京郊保护地土壤无机氮含量及矿化特征的影响

Effect of manipulation fertilization on soil inorganic nitrogen and characteristics of mineralization of protected soils in Beijing suburb

通过研究5年连续调控施肥保护地的土壤无机氮含量状况,结合田间原位培养的方法研究其表层土壤矿化特征,以了解不同调控施肥的土壤供氮能力,为京郊保护地氮素调控提供理论与现实依据。结果表明,不施肥和单施有机肥处理在作物生育期内,土壤表层无机氮处于耗竭状态;其它处理无机氮含量呈逐渐增长趋势,接近收获时又有所下降,表现为习惯施氮处理>1.5倍推荐施氮处理>推荐施氮处理>0.5倍推荐施氮处理,且各处理间差异显著。各处理矿化速率的差异在追肥后开始显现明显效果;至收获时,单施有机肥、推荐施氮和1.5倍推荐施氮处理累积矿化量分别达81.5、86.3和97.7 kg/hm2,已接近推荐施氮量(100 kg/hm2),习惯施氮处理达164.7 kg/hm2,较其它处理显著提高82%～438%。可见,5年调控施肥对降低土壤无机氮含量有积极作用,但土壤矿化量仍然非常高,可见,忽略土壤氮矿化量,将影响氮肥用量推荐和作物氮素平衡。

In this paper,the effect of manipulation fertilization for five years on protected soil inorganic nitrogen was studied,as well as the field plot experiment in situ incubation was carried out to study the dynamics of surface soil nitrogen mineralization rate,thus providing a theoretical and practical basis for nitrogen control of protected soils in Beijing suburb.The results showed that in the stage of crop growth,inorganic nitrogens in surface soil of the no fertilizer treatment and only manure treatment were almost exhausted and not good for crops to absorb;The development of inorganic nitrogens of other treatments had a upward trend but dropped off at the harvest stage,supplied as custom nitrogenous fertilizer treatment1.5 times of nitrogenous fertilizer recommendation treatmentnitrogenous fertilizer recommendation treatment0.5 times of nitrogenous fertilizer recommendation treatment and the effects were significant between each other.The effects of mineralization rates were significant after additional fertilizer;The mineralizations of only manure treatment,nitrogenous fertilizer recommendation treatment and 1.5 times of nitrogenous fertilizer recommendation treatment grew grealty and were close to nitrogenous fertilizer recommendation（100 kg/hm2）,accounted for 81.5,86.3 and 97.7 kg/hm2,the mineralization of custom nitrogenous fertilizer treatment was increased by 82%~438% and accounted for 164.7 kg/hm2.Therefore,manipulation fertilization was positive to decrease soil inorganic nitrogen but ignoring mineralization would have worse influence on nitrogenous fertilizer recommendation and nitrogen balance of crop.