秸秆深埋下灌水量对土壤水盐分布与夏玉米产量的影响

Effects of Irrigation Amount on Soil Water and Salt Distribution and Summer Maize Yield under Deeply Buried Straw

为探究秸秆深埋下土壤水盐分布与夏玉米产量对灌水量的响应,于2017年和2018年在河套灌区进行了秸秆深埋下单次灌水定额60 mm(W1)、90 mm(W2)、120 mm(W3)3个处理及常规135 mm为对照(CK)处理的大田试验。结果表明:秸秆深埋下耕作层含水率随灌水量的增加先增后减,成熟期W1处理的两年平均含水率较CK降低21.3%,而W2和W3较CK提高8.6%和9.4%;秸秆隔层持水量随灌水量的增加先增后降,成熟期W1持水量较CK平均降低10.9%,而W2和W3较CK平均提高16.1%和17.1%;生育期W1、CK处理在隔层积盐,W2、W3处理脱盐,生育末期W1和CK平均积盐率为27.0%和11.1%,而W2和W3平均脱盐率为7.6%和7.1%;W1和W3较CK平均减产20.9%和0.5%,W2较CK平均增产1%,但W1、W2、W3处理的水分利用效率较CK分别提高15.2%、17.3%和5.1%(P<0.05)。当耕层含盐量为1.45~1.48 g/kg,单次灌水定额为82~111 mm时,秸秆深埋耕作模式可实现节水稳产的目标。

To explore the response of soil water and salt distribution and yield of summer maize to irrigation amount under deeply buried straw,a field experiment of different irrigation amounts under deeply buried straw were carried out in Hetao Irrigation District in 2017 and 2018,respectively.The experiment consisted of four different irrigation amounts.It included irrigation amount of 60 mm(W1),irrigation amount of 90 mm(W2),irrigation amount of 120 mm(W3)under the deeply buried straw,and the local irrigation amount of 135 mm(CK treatment)under local tillage.The results showed that the moisture content of the tillage layer(0~35 cm)was increased first and then decreased with the increase of irrigation amount.At the maturity stage,the moisture content of W1 was 21.3%lower than that of CK treatment,while that of W2 and W3 treatments was increased by 8.6%and 9.4%on average compared with CK treatment.The water content of straw inter-layer(35~40 cm)was increased first and then decreased with the increase of irrigation amount.At the maturity stage,the water content of W1 treatments was decreased by 10.9%,while W2 and W3 treatments were increased by 16.1%and 17.1%compared with CK treatment.And there was no significant difference between W2 and W3 treatments.During the whole growth stage,W1 and CK treatments deposited salt in the straw inter-layer,while W2 and W3 treatments were desalted.At the end of growth stage,the salt accumulation rates of W1 and CK treatments were 27.0%and 11.1%,and the desalination rate of W2 and W3 were 7.6%and 7.1%on average.Compared with CK treatment,the summer maize yield of W1 and W3 treatment was decreased by 20.9%and 0.5%,while the increase of W2 was not significant,only 1.0%.But the water use efficiency of W1,W2 and W3 treatments were significantly increased by 15.2%,17.3%and 5.1%compared with that of CK treatment(P<0.05).And in the rainy year(2018),the water use efficiency was increased with the reduction of irrigation amount,which was due to the deeply buried straw promoted the growth of deep roots and absorbed water and nutrients from deep soil to supplement irrigation and achieved the goal of water-saving and stable yield.In addition,it was also found that under the deeply buried straw the salt content of the tillage layer and the irrigation amounts were significantly correlated with summer maize yield and water use efficiency(P<0.05),showing a quadratic function relationship,and the determination coefficient R^2 was not less than 0.935.The results showed that under the condition of deeply buried straw the appropriate salt content of the tillage layer was 1.45~1.48 g/kg,and the theoretical irrigation amount should be in the range of 82~111 mm,which could desalinate the root layer,improve the moisture content of the tillage layer,and achieve the goal of water-saving and stable yield.The research only analyzed the coupling effect between irrigation amount and deeply buried straw tillage mode,which enriched the theory of straw utilization in Hetao Irrigation District.But there was no specific analysis on effects of coupling effect of water,fertilizer and farm chemical on the growth of summer maize and the migration of water-salt,which needed to be further tested and studied.