滴灌和施用秸秆降低日光温室番茄地氮素淋溶损失

以一年两季设施番茄为对象,利用渗漏池收集渗漏液,研究了设施菜地不同灌溉模式(滴灌、漫灌)和施用有机物料(单施鸡粪M、鸡粪配施玉米秸秆M+C、鸡粪配施小麦秸秆M+W)对土壤矿质态氮、可溶性有机氮淋溶损失的影响。结果表明,日光温室栽培条件下,氮素的淋溶损失主要发生于秋冬季,滴灌和漫灌模式下,该季可溶性总氮淋失量占全年淋失量的56.8%和71.1%。漫灌模式下,冬春季和秋冬季可溶性总氮淋失量分别为114.3和281.1kg/hm~2,占单季氮投入量的12.5%和29.3%。与漫灌相比,滴灌使全年番茄产量和氮素吸收量分别显著提高15.6%和21.4%,氮素利用率(氮素吸收量/氮素投入量)显著提高47.5%,同时使全年矿质态氮(铵态氮+硝态氮)和可溶性有机氮淋失量分别降低68.6和47.4 kg/hm~2,降幅分别为33.1%和39.6%。与单施鸡粪相比,鸡粪配施秸秆(玉米或小麦)对番茄产量无影响,但显著降低灌溉水渗漏量和氮素淋溶损失量,使全年灌溉水渗漏损失量平均降低24.3%,全年矿质态氮和可溶性有机氮淋失量分别平均降低26.6%和33.7%。综上,可溶性有机氮在氮素淋溶损失中不可忽视,滴灌模式通过降低渗漏液中氮的浓度,配施秸秆通过减少灌溉水的渗漏损失,进而降低可溶性氮的淋溶损失。

Drip irrigation and application of straw reducing nitrogen leaching loss in tomato greenhouse

The excess fertilizers and irrigation water had resulted in low resource use efficiency, soil degradation, and ecosystem environment problems in greenhouse production system in China. How to maintain the good yield, and improve the resource use efficiency, reduce the environmental impacts of fertilizer, especially the N fertilizer, has become the problem that needs to be solved urgently. A long-term field experiment was conducted from 2008 to 2016 to evaluate the effect of different irrigation modes (drip irrigation and flood irrigation) and application of chicken manure combined with or without wheat straw or maize straw on tomato yield, recovery rate of added N, N leaching in the form of mineral N and dissolve organic N in solar greenhouse using a percolation pond. The percolation pond is 2 m long, 1 m wide and 0.9 m deep. At the second day after irrigation, the water leakage was sampled to measure the mineral N and total dissolved N content. Amounts of irrigation water under the drip and flood irrigation modes, which were 1173 and 1205 mm, respectively. The results showed that the yield of tomato was 105.8-127.4 and 70.6-95.9 t/hm2 in winter-spring and autumn-winter seasons, respectively. Compared with traditional flood irrigation mode, drip irrigation mode significantly increased tomato yield by 11.4% in winter-spring season, and by 21.7% in autumn-winter season. Nitrogen utilization (nitrogen uptake/nitrogen input) was 33.7% and 29.4% in winter-spring and autumn-winter seasons, respectively. The N utilization under drip irrigation mode was higher by 10 percent point in winter-spring season, and by 14.2 percent point in autumn-winter season than flood irrigation mode. Under the flood irrigation mode, the leached total dissolved N was as high as 114.3 and 281.1 kg/hm2, and accounted for 12.5% and 29.3% of the total applied N in winter-spring and autumn-winter seasons, respectively. Leached mineral N under the flood irrigation mode was 85.6 and 207.0 kg/hm2 in winter-spring and autumn-winter season, respectively. The irrigation amount of drip irrigation and flood irrigation had little difference for the whole year, but the amount of water leakage was significantly higher under the drip irrigation mode, the content of mineral N under the drip irrigation mode was lower by 51.1% than that of the flood irrigation mode, thus, the accumulated leached mineral N decrease by 80.1 kg/hm2 (38.7%), and the accumulated leached dissolved organic N decreased by 48.9 kg/hm2 (53.7%) in autumn-winter season. Application of wheat or maize straw had no effect on tomato yield, but significantly reduced annual irrigation water leakage by 24.3%, annual mineral N by 26.6% and annual dissolved organic N leaching loss by 33.7%. In general, the amount of dissolved organic N leaching loss should be considerable, drip irrigation mode decreased the N content in the water leakage and long-term addition of straw reduced the amount of water leakage, then additional application the straw under the drip irrigation mode is an useful field management to decreased the leach N.