易涝易渍棉田水文过程及其对棉花产量的影响

Hydrological Process in Filed Vulnerable to Water-logging and Its Influence on Cotton Yield

以2003～2008年的田间观测资料为基础,研究了易涝易渍棉田水文过程对农业涝渍灾害防治及其评估的特点,探讨了易涝易渍棉田水文过程及其对棉花产量的影响。结果表明,易涝易渍棉田具有地下水埋深浅、对降水很敏感的特点。30mm以上降水就可引起地下水位明显抬升;降水可引起棉田间歇性多次受渍、受涝,会引起作物不同程度减产。当受涝(田间积水深度5～15cm)3d,地下水埋深小于30cm的时间累积达到12～22d时,可造成棉花减产13%～22%;当受涝5～6d,地下水埋深小于30cm的时间累积达到21～33d时,可造成棉花减产35%～50%。在不受涝仅受渍的情况下,当地下水埋深小于30cm的时间累积达3～4周时,可造成作物减产14%～31%,5周以上时则造成作物减产过半。回归分析表明,作物减产程度与受涝、受渍程度指标之间有显著的相关关系,在地下水位长期偏高、田间浅淹3～6d的情况下,渍对作物的影响大于涝。

Agriculture in control and evaluation of waterlogged disaster that hydrological process of cropland vulnerable to water-logging and hydrological process in a filed vulnerable to water-logging and its influence on cotton yield are studied based on field investigation in 6years from 2003to 2008.The results showed that : cropland vulnerable to water-logging is characterized by a shallow groundwater and being sensitive to rainfall,more than 30mm of precipitation may result in an obvious rise of groundwater table;rainfall may cause cotton field suffering from intermittent subsurface water-logging and surface water-logging repetitiously,and result in reduction of the output to varying degree.When cotton field underwent surface water-logging(the accumulated water in the fields is about 5～15cm) for 3days(or 5～6days) and meanwhile the accumulated time of groundwater depth less than 30cm lasted for 12～22days(or 21～33days),the reduction of output may be 13%～22%(or 35%～50%).When cotton field was merely exposed to subsurface water-logging,the accumulated time of groundwater depth less than 30cm was up to 3～4weeks(or more than 5weeks) the reduction of output may reach 14%～31%(or more than 50%).Regression analysis indicated that the reduction of crop output(R d) has an extremely significant correlativity with indicators that reflect cotton field meet with surface and subsurface water-logging,subsurface water-logging impact on cotton is severe than surface water-logging in case that groundwater table is on the high side over a long period of time and the field was submerged in shallow water for 6days.