田间涝渍与棉花产量之间的关系

Relationship between Waterlogging and Cotton Yield

【目的】定量分析涝渍对棉花产量的影响。【方法】根据1999—2016年棉田5—8月涝渍监测资料,将田间涝渍分为4种情形:一次持续受渍过程、多次受渍过程、一次涝渍连续过程和多次涝渍过程。以地下水连续动态指标(SEW30)反映田间受渍程度,以降水引起的田间涝水深累积值(SFW)反映田间受涝程度,以田间积水期间地下水连续动态指标与地表水涝水深累积值之和(SFEW30)反映涝渍综合影响程度,研究了涝渍对棉花产量的影响。【结果】在棉花生育期内仅发生1次受渍过程,且地下水埋深小于30 cm的时间(Tg-30)为2～4 d,减产幅度在8%以内;多次受渍,且Tg-30介于10～20 d之间,减产幅度一般为10%～20%。在涝渍伴随发生条件下,花铃期受涝持续时间4～10 d,地下水埋设小于30 cm的持续时间为7～13 d,结果造成棉花减产25.8%～49.1%;无论苗期、现蕾期还是花铃期,半月内多次受涝、受渍,且受涝累计时间不少于5 d,棉花减产达35.0%～49.5%。此外,作物相对产量与SEW30、SFW、SFEW30极显著线性相关。【结论】多次受涝、受渍均造成棉花减产;相同持续时间的涝害和渍害,涝造成危害远大于渍害。

【Objective】The objective of this paper is to present a quantitative relationship between waterlogging and cotton yield based on seven years' experimental data.【Method】From May to August in each year from 1999 to 2016, we measured waterlogging in a cotton field and classified the waterlogging into four categories: subsurface waterlogging, multiple subsurface waterlogging, one subsurface waterlogging followed by surface waterlogging, combination of multiple subsurface waterlogging and surface waterlogging. Subsurface waterlogging was represented by accumulated groundwater depth when it was 30 cm below the ground surface(SEW30), and surface waterlogging was represented by rainwater dynamic index(SFW) that was the accumulated surface water depth within a defined period. The combined effect of surface and subsurface waterlogging(SFEW30) was expressed by the sum of SEW30 and SFW. The impact of these waterlogging events on cotton yield was analyzed based on experimental data collected in the seven years.【Result】Reduction in cotton yield was 8% for one-off subsurface waterlogging with groundwater table(Tg-30) was not shallower than 30 cm for 2~4 days, and 10%~20% for multiple subsurface waterlogging when the accumulated waterlogging time Tg-30 was between 10 days to 20 days. For subsurface waterlogging followed by surface waterlogging, the reduction in cotton yield was 25.8%~49.1% when the cotton was under waterlogging for 4~10 day during blossoming and/or boll-forming stages with Tg-30 being 7~13 days. The reduction in cotton yield was 35.0%~49.5% no matter what stage the cotton was, if the plants suffered multiple waterlogging within 5 days and the cumulative time of the waterlogging lasted more than five days.【Conclusions】The waterlogging indexes SEW30, SFW, and SFEW30 proposed in this paper can be used to predict reduction in cotton yield.