摘要
在研究咸水灌溉对土壤和作物的影响过程中,对土壤盐分监测相对困难,而监测灌溉水的盐分更简单易行,但作物不同时期灌溉咸水的矿化度阈值较难确定。本文以2007—2015年在河北省衡水旱农节水试验站进行的长期咸水灌溉试验数据(灌溉水设置1 g·L^(-1)、2 g·L^(-1)、4 g·L^(-1)、6 g·L^(-1)和8 g·L^(-1)共5个矿化度;冬小麦生长期间灌溉3次水)为基础,以矿化度为1 g·L^(-1)灌溉水为淡水对照,调查不同处理小麦的相对出苗率、相对籽粒产量及土壤盐分等作物生长、产量和环境变化指标,并采用FAO分段函数方法,分析了‘石家庄8号’冬小麦多年咸水灌溉的矿化度阈值及其影响因素。结果表明,采用4 g·L^(-1)和6 g·L^(-1)咸水灌溉,多年平均小麦出苗率相当于淡水的93.8%(P>0.05)和70.4%(P<0.05),多年平均产量相当于淡水灌溉的86.0%(P<0.05)和65.3%(P<0.05),用小于4 g·L^(-1)的咸水灌溉,籽粒产量(产量变化小于15%)和出苗率不是影响咸水灌溉矿化度阈值的限制因素。经计算冬小麦多年咸水灌溉矿化度阈值为2.14~3.95 g·L^(-1),平均值为3.19 g·L^(-1),变异系数为21.1%。综合考虑产量和土壤盐分累积风险确定河北低平原冬小麦长期灌溉咸水矿化度阈值为2.47 g·L^(-1)。矿化度阈值与播前1 m土壤盐分有一定负相关关系(相关系数-0.587),与淡水灌溉产量呈一定正相关关系(相关系数0.516)。土壤盐分累积风险分析结果表明,按照灌溉咸水矿化度与土壤平均盐分拟合的指数方程预测,采用2.47 g·L^(-1)咸水连续9年灌溉,0~20 cm耕层土壤未达到盐渍化水平(平均土壤盐分预测值0.98 g·kg^(-1)),而1 m土体出现轻度盐渍化(平均盐分含量预测值1.17 g·kg^(-1)),土壤盐分稍有累积,但未对冬小麦产量造成明显影响。由此来看,以2.47 g·L^(-1)咸水长期灌溉造成土壤严重盐渍化的风险较小。
Compared with soil salts content measurement, irrigation water salts are much easier to be monitored and regulated under saline water irrigation of crop cultivation. However, the salinity threshold of irrigation water（STIW） is a rather complex and difficult parameter to set. In this study, the STIW value for winter wheat was estimated based on a long-term experiment（2007–2015） at the Dry-land Farming Station in Hengshui, Hebei Lowland Plain. In the study, different salinities of irrigation water [1 g×L-1（control）, 2 g×L-1, 4 g×L-1, 6 g×L-1 and 8 g×L-1] were used to determine STIW under long-term saline water irrigation of ‘Shijiazhuang 8＇ wheat variety. The relative germination and yield of wheat, soil salinity content and characteristics of wheat growth were measured under different conditions. Yearly STIW was calculated by using the FAO piecewise linear model and the final result decided through comprehensive considerations of the risks of both yield loss and soil salt accumulation. The factors influencing annual fluctuations of STIW were also determined. The results showed that the relative emergence rates of winter wheat under 4 g×L-1 and 6 g×L-1 treatment were 93.8%（P 0.05） and 70.4%（P 0.05）, the relative yield were 86.0%（P 0.05） and 65.3%（P 0.05）, respectively, compared with the control. Thus the grain yield loss（no more than 15%） and emergence of winter wheat were not limiting factors of STIW of wheat. For the 9-year data, the calculated STIW was within 2.14–3.95 g×L-1, with an average of 3.19 g×L-1 and a variation coefficient was 21.1%. The final value of STIW that took into accounts of soil salt accumulation risk and wheat yield was 2.47 g×L-1. STIW was negatively correlated with soil salt in the 0–100 cm soil profile at pre-sowing stage（coefficient r = -0.587）, but positively correlated with fresh water irrigated yield（r = 0.516）. The result of estimated risk of soil salt accumulation indicated that exponential model had the best simulation effect for the relationship between irrigation water salinity and soil salt. After 9 years of consecutive saline water irrigation at STIW, average soil salt was 0.98 g·kg-1 in the 0–20 cm soil layer and was 1.17 g·kg-1 in the 0–100 cm soil profile. There was a slight accumulation of soil salt, but no significant effect on winter wheat yield. The risk of soil salinization due to long-term 2.47 g×L-1 saline water irrigation was weak in Hebei Lowland Plain.
出处
《中国生态农业学报》
CAS
CSCD
北大核心
2016年第5期643-651,共9页
Chinese Journal of Eco-Agriculture
基金
国家科技支撑计划项目(2013BAD05B02
2012BAD05B02)资助~~
关键词
河北低平原
冬小麦
咸水
长期灌溉
矿化度阈值
Hebei Lowland Plain
Winter wheat
Saline water
Long-term irrigation
Salinity threshold
