摘要
依据咸水冰盐水融离原理,利用土柱模拟试验,设置4个灌溉方式,分别为对照处理(淡水)、咸水灌溉、咸水结冰灌溉和咸水结冰灌溉+秸秆覆盖,研究咸水结冰灌溉条件下土壤水盐的独特运移机制。结果表明,与淡水灌溉相比,咸水灌溉处理表层0~40 cm土壤水分含量偏低,而深层土含水量则较高;咸水结冰灌溉下这一规律更为明显。但配合秸秆覆盖措施能在一定程度提高咸水结冰灌溉后各土层土壤含水量。咸水直接浇灌使各土层土壤盐度EC1:5偏高,盐分累积量增大,且盐分具有明显表层聚集特性,表层0~40 cm盐分累积量占0~80 cm土体的62.2%;而咸水结冰后灌溉则显著降低表层0~40 cm土层的盐分累积,仅占18.6%;咸水结冰后灌溉配合秸秆覆盖则进一步促进表层的脱盐率提高,特别在0~10 cm土层,土壤盐度仅为0.15 dS·m -1,盐分累积67.8 g·m-2,与淡水处理间差异未达显著水平(P〉0.05)。咸水结冰灌溉配合秸秆覆盖可促进表层土壤的脱盐,使土壤根系分布密集层保持较低盐分水平,缓解或消除盐分对作物生长的危害,使玉米的生长状况达到淡水灌溉处理的效果。
Freshwater is widely regarded as the most important and fundamental natural resource that is integral to all ecological and societal activities, including food and energy production, industrial development and human health. At the global or even country level, there exists significant spatio-temporal variability in renewable water resources, resulting in severe freshwater shortages in some regions of the world. Underground salt-water deposits could not meet domestic water supply requirements due the generally high salt content even for agricultural irrigation, let alone for domestic consumption. So desalination, which is the separation of water form salt solution for freshwater supply, could be a viable option needing facilitation. Four laboratory irrigation modes were designed in Dezhou Experiment Station of Chinese Academy of Agricultural Sciences. The irrigation modes included control treatment (freshwater irrigation, CK), saline water irrigation (SW), saline ice-melt water irrigation (MI) and saline ice-water irrigation plus wheat straw mulch (MI+SW). The mechanisms of water and salt movement in the soil during saline ice-water melt were studied in a soil column experiment. Corn was planted in the soil column after seven days and the effects of saline ice-melt water irrigation on soil water content, salt movement and corn growth determined. The results showed soil water content in the 0-40 cm layer under saline water irrigation treatment was lower and that in the deeper soil layer higher compared to that under freshwater irrigation treatment. Compared with freshwater irrigation treatment, saline ice-melt water irrigation treatment also showed a similar trend; where there was lower water content in surface soil and higher water content in deep soil layers. However, wheat straw mulching increased soil profile water content. Soil salinity under freshwater irrigation treatment was very low in the 0-60 cm soil later, less than 0.2 dS·m-1. In the 60-80 cm soil layer, however, salinity increased significantly (0.4 dS·m-l), although still much lower than that under saline water irrigation treatment. While saline ice-water irrigation treatment decreased salinity in the 0-40 cm soil layer, it increased salinity in deep soil layers. Salt accumulation was higher under saline water irrigation treatment with aggregation properties in surface soil. The 0-40 cm soil layer accounted for 62.2% of accumulated salt in the 0-80 cm soil layer. However, accumulated salt in the 0-40 cm was 18.6% of accumulated salt in the 0-80 cm soil layer under saline ice-water irrigation treatment. Saline ice-water irrigation plus straw mulching accelerated desalinization of soil surface, especially in the 0-10 cm soil later. Salinity under saline ice-water irrigation plus straw mulching was only 0.15 dS'm-1 with a salt content of 67.8 g.m-2, which showed no significant difference with freshwater irrigation treatment. This suggested gradual reduction in total salt content of melt-water. Saline ice-water irrigation improved surface soil desalination and maintained low root-zone soil salinity, which alleviated or even eliminated salinity-driven hazards in agricultural crop and soil environment. Agricultural soil conditions even improved further when saline ice-water irrigation was combined with straw mulching, under which corn graw well as under freshwater irrigation. In a conclusion, underground salt water was usable during ice-melt in the Huang-Huai-Hai Plain.
出处
《中国生态农业学报》
CAS
CSCD
北大核心
2012年第9期1210-1215,共6页
Chinese Journal of Eco-Agriculture
基金
中央级公益性科研院所基本科研业务费专项资金(2011-26)
公益性行业(农业)科研专项经费项目(200903001)资助
关键词
咸水灌溉
咸水结冰灌溉
秸秆覆盖
土壤水盐
脱盐率
玉米生长
Saline water irrigation, Saline ice-water irrigation, Crop straw mulching, Soil water and salt, Desalinization ratio,Maize growth