夏季种植甜玉米减少果类菜田土壤氮素损失的效果

Effect of Summer Sweet Corn Planting on the Reduction of Soil N Loss in Greenhouse Vegetable Field

研究冬、春茬番茄收获后种植夏季填闲甜玉米对土壤剖面无机氮含量及氮素损失的影响,以解决我国北方设施果类蔬菜生产中夏季休闲期较长,夏季土壤氮素矿化强烈,无机氮积累严重,下茬定植前后大水漫灌容易导致淋洗损失等问题。结果表明:在夏季期间没有任何肥料投入和灌溉,甜玉米生长状况良好,其生物量鲜重达66.7 t/hm2,干物质累积为5.9 t/hm2,玉米穗净鲜重达7.5 t/hm2,农民净收入达8 000元/hm2;甜玉米地上部可带走土壤氮素128.1 kg/hm2,减少土壤无机氮累积数量403.1 kg/hm2,从而减少氮素损失风险。夏季种植玉米不仅可以减少氮素损失,而且其根茬还田作为一个很好的碳源补充,改善菜田土壤环境,提高菜田土壤生物肥力。

The fallow period is relatively long in the greenhouse fruit vegetable production of North China.Because of strong nitrogen net mineralization and nitrate accumulation in summer fallow period,nitrogen leaching losses easily occur due to excessive irrigation at transplanting in the autumn.In this paper,sweet corn as N-catch crop was planted in summer after winter-spring tomato was harvested in order to study the effect on soil nitrogen loss in fruit vegetable field.The results indicated that sweet corn could grow well without fertilizer or irrigation supply,and the fresh weight and dry weight of biomass were up to 66.7 t/hm^2 and 5.9 t/hm^2,respectively.The net weight of spike reached 7.5 t/hm^2,which increased the farmers income by over 8 000 yuan/hm^2;the nitrogen uptake of sweet corn aboveground could reach 128.1 kg N/hm^2,and depleted Nmin residue in the soil profile of 1.8 m by 403.1 kg N/hm^2.Sweet corn,as a summer catch crop,could not only reduce the soil nitrogen loss,but the root residue incorporation could also create a chance to replenish organic carbon for changing soil environment,and improving soil bio-fertility.