| 摘要: |
| 在年降水量415 mm的黄土高原中部黄绵土上，以春小麦(Triticum aestivum)为供试作物进行大田试验，研究了地膜覆盖（设不覆膜、播种后覆膜30 d、覆膜60 d和全程覆膜）和施氮（设不施氮和施氮75 kg/hm2）对春小麦耗水量和水分利用效率的影响。结果表明，地膜覆盖对春小麦耗水量和水分利用效率的影响与底墒和覆膜进程有关。增加底墒和施肥，春小麦全生育期耗水量显著增加。高底墒处理的平均耗水量（327.7 mm）比低底墒（285.4 mm）高42.3 mm，差异达显著水平(P＜0.05)；施氮后，耗水量也显著增加，不施氮时，平均耗水量为299.0 mm，施氮后平均为314.1 mm，施氮比不施氮增加15.1 mm。在降水相对丰富年份，对低底墒处理，不同覆膜进程对春小麦全生育期耗水量没有显著影响，而对高底墒处理，覆膜30 d和60 d作物全生育期耗水量显著高于对照和全程覆膜，但覆膜30 d和60 d间、全程覆膜和不覆膜间的差异均不显著。因此在降水丰富年份，全程覆膜并没有使作物全生育期耗水量减少，同时也并没有使作物收获后的残留底墒增加。从总体上看，覆膜处理比底墒和施肥对作物耗水量的影响小。无论是用地上干物质计算，还是用籽粒计算，施氮后水分利用效率明显增加。地膜覆盖对水分利用效率的影响与底墒和覆膜进程有关。在降水正常年份，当底墒不足时，覆膜并不能显著增加水分利用效率；而在高底墒条件下，无论是对干物质，还是对籽粒，覆膜后水分利用效率显著提高(P＜0.05)。虽然覆膜60 d和全程覆膜间的水分利用效率均显著高于不覆膜，但覆膜60 d和全程覆膜间的水分利用效率差异不大，未达到显著水平。以上结果充分说明，无论底墒状况如何，全程覆膜对提高水分利用效率没有实际意义。 |
| 关键词: 地膜覆盖 春小麦 水分利用效率 耗水量 |
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| 基金项目:国家自然科学基金项目(30230230,39970151和39970459)；2002年度教育部全国优秀青年教师资助项目(20022096)；国家重点基础研究专项项目(G2000018603)；国家基础研究重大项目前期研究专项项目“半干旱黄土植被景观覆盖格局与生态系统功能调控”；黄土高原土壤侵蚀与旱地农业国家重点实验室基金项目(10501-104);农业科技跨越计划项目(2000-6) |
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| Effect of plastic film mulching on spring wheat's water consumption and water use efficiency in semiarid agro-ecological system |
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| Abstract: |
| A field experiment was carried out on cultivated loessial soil in semiarid area with 415 mm precipitation and spring wheat (Triticum aestivum) used as an indicating crop to study the effects of plastic film mulching period(including no mulching,mulching for 30 days,mulching for 60 days,after sowing and mulching for whole growing period) and nitrogen fertilizer application (including no nitrogen application and nitrogen application N 75 kg/hm2) on the spring wheat’s water consumption and water use efficiency (WUE).The results showed that the effects of plastic film mulching on spring wheat’s water consumption and water use efficiency (WUE) had relation with soil water storage amount in soil profile before sowing and plastic film mulching course.Spring wheat’s water consumption in all growing period remarkably increased when soil water storage amount in soil profile before sowing increased and nitrogen fertilizer was applied.The water consumption in high soil water storage amount (327.7 mm) in soil profile before sowing was higher than low soil water storage amount (285.4 mm) in soil profile before sowing,and the difference was 42.3 mm (P<0.05);water consumption was also increased when nitrogen fertilizer was applied,and the average water consumption was 299.0 mm when there was no nitrogen fertilizer,while it was 314.1 mm when nitrogen fertilizer was applied,the difference was 15.1 mm.In year with normal precipitation,the different plastic film mulching course had no remarkable effect on the water consumption of spring wheat’s growing period in the treatment of low soil water storage amount in soil profile before sowing,while in the treatments of high soil water storage amount in soil profile before sowing,the water consumption for the plastic film mulching for 30 days and 60 day’s treatment were higher than control and plastic film mulching for the whole growing period,but the difference between the two treatments wasn’t significant,and the difference between plastic film mulching for the whole growing period and control was also not significant.So in the year with normal rain,water consumption was not decreased and the residual soil water storage amount at harvest wasn’t increased in the treatment of plastic film mulching for the whole growing period.As a whole,the treatment of film mulching had less effect on crop’s water consumption than the treatment of nitrogen fertilizer.WUE was apparently increased no matter it was counted on dry matter or on seed.The effect of plastic film mulching on WUE had relation with that of soil water storage amount in soil profile before sowing and mulching course.In the normal rain year,the WUE wasn’t remarkably increased for plastic film mulching when the soil water storage amount in soil profile before sowing was scarce,but it was remarkably increased (P<0.05) when the soil water storage amount in soil profile before sowing was high no matter WUE was counted on dry matter or on seed.Though the WUE of plastic film mulching for 60 days and that of plastic film mulching for the whole growing period were remarkably higher than control,the WUE's difference between the two treatments wasn’t significant.The above result adequately show that plastic film mulching for the whole growing period have no realistic significance in WUE’s increase regardless of soil water storage amount in soil profile before sowing. |
| Key words: plastic film mulching spring wheat water use efficiency water consumption |
