南疆绿洲棉田冬灌期灌排水氮含量特征研究

Characteristics of nitrogen content in irrigation and drainage water of cotton field in winter irrigation in Southern Xinjiang oasis

新疆南疆绿洲棉田普遍进行冬春季灌溉,高定额灌水淋洗土壤盐分的同时也会造成土壤养分的损失。通过研究冬灌期棉田灌排水氮含量特征,有助于棉花生产中水氮资源高效利用。选择南疆绿洲阿拉尔垦区成片棉田,定点采集冬灌前及冬灌后灌排水样,测定铵态氮、硝态氮和总氮浓度,分析冬灌措施对棉田氮浓度的影响。冬灌前和冬灌后,棉田排水中铵态氮、硝态氮和总氮浓度均显著高于灌溉水。冬灌前,灌溉水中三者浓度分别为0.198 mg·L^(-1)、0.417 mg·L^(-1)、0.948 mg·L^(-1),棉田排水三者浓度分别为0.337 mg·L^(-1)、0.753 mg·L^(-1)、1.710 mg·L^(-1);冬灌后,灌溉水中三者浓度分别为0.280 mg·L^(-1)、0.670 mg·L^(-1)、1.308 mg·L^(-1),棉田排水中三者浓度分别为0.756 mg·L^(-1)、1.602 mg·L^(-1)、3.344 mg·L^(-1)。冬灌后棉田排水铵态氮、硝态氮、总氮浓度均比冬灌前高,三者浓度分别升高124%、113%、96%。从各级排渠来看,冬灌后农排水铵态氮、硝态氮、总氮浓度分别为1.071 mg·L^(-1)、2.760 mg·L^(-1)、5.552 mg·L^(-1),均显著高于支排、干排水。南疆绿洲棉田冬灌前及冬灌后,灌排水氮浓度特征分析表明:棉田排水中铵态氮、硝态氮和总氮浓度均高于灌水,冬灌后农排水中铵态氮、硝态氮和总氮浓度均高于支、干排水。

Irrigation is generally carried out in winter and spring in oasis cotton fields in southern Xinjiang,and high-quota irrigation leaching soil salt also causes the loss of soil nutrients.Study on nitrogen content characteristics of irrigation and drainage water in cotton field during winter irrigation is helpful for efficient utilization of water and nitrogen resources in cotton production.Selecting a cotton field in Alar Reclamation Area of South Xinjiang Oasis,collect irrigation and drainage samples before and after winter irrigation.The contents of ammonium nitrogen,nitrate nitrogen and total nitrogen were determined,and the effects of winter irrigation measures on nitrogen content in cotton fields were analyzed.Before and after winter irrigation,the concentrations of ammonium nitrogen,nitrate nitrogen and total nitrogen in cotton field drainage were significantly higher than those in irrigation water.Before winter irrigation,the concentrations of the three in irrigation water were 0.198 mg·L^(-1),0.417 mg·L^(-1) and 0.948 mg·L^(-1) respectively,and the concentrations in cotton field drainage were 0.337 mg·L^(-1),0.753 mg·L^(-1) and 1.710 mg·L^(-1) respectively;After winter irrigation,the concentrations of the three in irrigation water were 0.280 mg·L^(-1),0.670 mg·L^(-1) and 1.308 mg·L^(-1) respectively,and those in cotton field drainage were 0.756 mg·L^(-1),1.602 mg·L^(-1) and 3.344 mg·L^(-1) respectively.After winter irrigation,the concentrations of ammonium nitrogen,nitrate nitrogen and total nitrogen in cotton field drainage were higher than those before winter irrigation,and their concentrations increased by 124%,113%and 96%respectively.According to drainage channels at all levels,the concentrations of ammonium nitrogen,nitrate nitrogen and total nitrogen in agricultural drainage after winter irrigation were 1.071 mg·L^(-1),2.760 mg·L^(-1) and 5.552 mg·L^(-1) respectively,which were significantly higher than those in branch drainage and dry drainage.The analysis of nitrogen concentration characteristics of irrigation and drainage before and after winter irrigation in oasis cotton field in southern Xinjiang shows that:The concentrations of ammonium nitrogen,nitrate nitrogen and total nitrogen in cotton field drainage are higher than those in irrigation,and the concentrations of ammonium nitrogen,nitrate nitrogen and total nitrogen in agricultural drainage after winter irrigation are higher than those in branch and dry drainage.