华北平原免耕土壤积温特征对冬小麦的影响

Characteristic of Accumulated Soil Temperature and Effects on Winter Wheat under No-tillage, North Plain, China

为研究不同耕作方式农田土壤积温特征及其对冬小麦生长发育和产量的影响,本试验将土壤积温与冬小麦的生育时期结合,合理评价免耕农田热量资源的利用状况,为该技术的改善提供理论依据。研究于2005年在河北省栾城县设置了翻耕、旋耕、免耕处理,系统测定了冬小麦田耕层土壤温度和冬小麦的生长动态。结果表明:免耕各生育时期土壤平均温度最低;土壤活动积温在出苗期高于翻耕,幼苗期和返青拔节期高于旋耕,但耗时较长;免耕越冬期寒冷度较低,具有保温效应;免耕农田低温使冬小麦出苗晚1d,分蘖晚3d,返青推迟2d;免耕冬小麦株高降低,分蘖率、叶面积指数、干物质量在各时期均显著低于翻耕和旋耕,且显著降低产量37.3%和33.7%。免耕农田土壤低温阻碍作物生长,推迟冬小麦生育时期是降低地上部生物量和产量的主要原因,热量资源利用效率低,建议发挥免耕节约农时的作用适时早播,利用强分蘖力品种提高免耕冬小麦产量。

An experiment was operated to explain soil temperature characteristics under different tillage systems and effects on growth, development and yield of winter wheat. Soil accumulated temperature and growing stages of winter were combined together to evaluate the efficiency of thermal of no- tilled （NT） field. Taking conventional tillage （CT）, rotary tillage （RT）, and NT as treatments, the field experiment was carried out in Luancheng County, Hebei Province, in 2005. The dynamics of soil temperature under plough layer and winter wheat growth were systematically observed and got the following results. NT had the lowest average soil temperature in each stage of winter wheat. At emergence stage, the active accumulated soil temperature of NT was higher than that of CT. At seedling and revival stage, the active accumulated soil temperature of NT was higher than that of RT. However, NT needed more days to complete each growth stage than that of CT and RT. But during the hibernation stage, the soil was warmer under NT than CT and RT. Compared with CT and RT, the time of seedling emergence, tillering and revival in NT was delayed by 1 d, 3 d and 2 d, respectively. The height, rate of tillering, LAI and dry matter accumulation were reduced significantly in NT treatment. The yield was reduced by 37.3% and 33.7%. Therefore, the decreased growth and delayed development stages of winter wheat under NT by lower temperature were reasons of the lower above ground biomass and yield. The efficiency of thermal was lower under NT. The time saving effect of NT must be regarded and strong tillering breeds were advised for earlier sowing and yield increasing.