摘要
灌溉和氮肥的施用是保障干旱荒漠区农田生产的关键措施,但过量的氮肥会随水分淋溶至深层土壤或地下水中,从而导致氮素的损耗和地下水的污染。本研究以黑河中游荒漠绿洲过渡带两种开垦年限的农田土壤(风沙土和灰棕漠土)为研究对象,通过土柱模拟试验监测分析了玉米生育期和休闲期内土壤水分和温度的动态变化及硝态氮(NO_(3)^(-)-N)的淋溶规律,揭示了不同耕作年限农田土壤中硝态氮损耗的差异。结果表明:新绿洲农田深层渗漏及NO3--N的淋失主要发生在苗期-拔节期以及休耕期,深层渗漏年损失量97.65-105.1 mm,占年灌溉水总量(810 mm)的12%-13%,NO_(3)^(-)-N淋溶年损失量68.1-123.8 kg·hm^(-2),占年施氮总量的18.7%-34.2%,休耕期灌水致使生育期内土壤中大量积累的氮素淋溶至深层,NO3--N淋失量是当年生育期内NO_(3)^(-)-N淋失量的2.2倍;开垦年限较长的老绿洲农田在相同灌溉施肥条件下无深层渗漏和NO_(3)^(-)-N的淋失现象发生,其“蓄水保墒”及抑制水分和NO_(3)^(-)-N渗漏淋失的生态效应优于开垦年限较短的新垦绿洲农田。因此,为降低土壤水分损失和NO_(3)^(-)-N淋失风险,建议新绿洲农田生育期内减少春季灌溉次数或降低灌水定额,冬季休耕期降低灌水定额或采取免冬灌措施,以此保证灌溉水资源的优化利用并减少农田氮素的淋失。
Irrigation and nitrogen fertilizer application are the key measures to ensure farmland production in arid desert areas,but excessive nitrogen fertilizer will leach into deep soil or groundwater,resulting in nitrogen loss and groundwater pollution. In this study,two kinds of farmland soils with different reclamation years in the desert oasis transition zone in the middle reaches of Heihe River were taken as the research objects. Through soil column simulation experiment,the dynamic changes of soil moisture and temperature and the leaching law of nitrate nitrogen in maize growth period and leisure period were monitored and analyzed,and the differences of nitrate nitrogen loss in farmland soils with different cultivation years were revealed. The results showed that the soil water leakage and nitrate leaching of Newly cultivated sandy cropland mainly occurred in the seedling stage to elongation stage and the fallow stage. The annual loss of deep leakage ranged from 97.65 mm to 105.1 mm,accounting for 12%-13% of the total annual irrigation water(810 mm). The annual loss of NO_(3)^(-)-N leaching ranged from 68.1 kg·hm^(-2)to 123.8 kg·hm^(-2),accounting for 18.7%-34.2% of the total annual nitrogen application. Irrigation in fallow period led to the accumulation of a large amount of nitrogen leaching in the soil during the growth period,and the NO_(3)^(-)-N leaching loss was 2.2 times of that in the current growth period. Under the same irrigation and fertilization conditions,there were no deep seepage and NO_(3)^(-)-N leaching occurred in the old oasis farmland. Moreover,the“water preservation”effect of old oasis farmland was better than newly cultivated sandy cropland. Therefore,we suggested that reduce the irrigation frequency or irrigation quota in spring during the growing period of newly cultivated sandy farmland,and reduce irrigation quota or no winter irrigation in winter fallow period,so as to ensure the optimal utilization of irrigation water resources and reduce nitrogen leaching loss in farmland.
作者
李晶
何志斌
王建兵
马登科
王丽莎
Li Jing;He Zhibin;Wang Jianbing;Ma Dengke;Wang Lisha(Gansu Academy of Social Sciences,Lanzhou 730070,China;Linze Inland River Basin Research/Key Laboratory of Inland River Basin Science,Northwest Institute of Eco-Environment and Resource,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049.China)
出处
《中国沙漠》
CSCD
北大核心
2022年第5期245-257,共13页
Journal of Desert Research
基金
国家自然科学基金创新研究群体项目(41621001)
甘肃省科技厅软科学专项项目(21CX6ZA015)
甘肃省陇原青年创新创业(个人)项目。
关键词
绿洲农田
含水率
温度
硝态氮
渗漏
淋溶
oasis farmland
moisture content
temperature
nitrate nitrogen
leakage
leaching
