旱地小麦休闲期覆盖保水与产量构成因素的关系

Effects of mulching in fallow period on soil moisture and yield components of dryland wheat

为探索旱地小麦休闲期覆盖保水、增产技术途径,于2011—2012年在山西省闻喜县进行了前茬小麦收获后30 d或60 d深翻后进行地面全覆盖、半覆盖、不覆盖的大田试验,研究休闲期覆盖时间和覆盖方式对土壤水分和小麦产量形成的影响。结果表明：休闲期覆盖后,播种-孕穗期土壤蓄水量显著提高,尤其播种期140-200 cm,越冬期和返青期160-300 cm,拔节期80-160 cm,孕穗期0-120 cm、200-300 cm土层效果明显,且以前茬小麦收获后30 d采用全覆盖效果较好;覆盖后,越冬-孕穗期群体分蘖数增加,成熟期植株干物质量显著提高,穗数显著提高（3%-14%）,产量显著提高（171-815 kg·hm^-2）;全覆盖处理成穗率、经济系数、产量及其构成因素均高于半覆盖,且以麦收后30 d覆盖效果较好;播种期土壤水分与穗数、穗粒数和产量关系密切,尤其是深层土壤水分,且直至孕穗期200-300 cm土壤水分与干物质量、穗数和产量关系仍密切;休闲期提早覆盖有利于蓄保休闲期降水于深层,且至孕穗期300 cm深处土壤水分仍有提高;有利于构建合理群体,主要通过提高穗数实现增产,且以全覆盖效果最好。

In order to explore the technology for soil water storage and yield improvement of dryland wheat by mulching,an experiment was carried out in Wenxi County,Shanxi Province from 2011 to 2012. The effects of mulching methods and time on water storage and yield formation of dryland wheat were studied through whole mulching,half mulching and no mulching at 30 and60 days after wheat harvest. The results showed that the soil water storage from sowing stage to booting stage significantly increased by mulching. Especially,the soil water storage of 140- 200 cm layer at sowing stage,160-300 cm layer at wintering stage and turning green stage,80-160 cm layer at elongation stage,0-120 cm and 200-300 cm layers at booting stage increased obviously. The overall effect of whole mulching at 30 days after wheat harvest was best. The tiller number increased from wintering stage to booting stage,and dry matter significantly increased at mature stage. The ear number was significantly improved,with an increase of 3%-14%. Furthermore,the yield of wheat dramatically increased by 171- 815 kg·hm^-2. The percentage of earbearing,economic coefficient,yield and its component factors with whole mulching were higher than those with half mulching,with a better effect for whole mulching at 30 days after wheat harvest. The results also showed that the soil water storage at sowing stage was closely related to ear number,grain number per spike and yield,especially for the deep water storage. Until the booting stage,the water storage of 200-300 cm layer was still closely associated with dry matter,ear number and yield. To sum up,early mulching during fallow period is beneficial to storing the rainfall,especially improving the water storage in deeper layers up to the depth of 300 cm; early mulching is also beneficial to building a reasonable community and enhancing the yield through improving the ear number,with a better effect for the whole mulching.