耕作与施肥措施对江淮地区白土理化性质及水稻产量的影响

针对连续旋耕白土田耕层浅薄、下层土壤黏重紧实、养分分布不均衡等问题,探索适合于白土稻田的耕作与施肥措施,以进一步提高江淮地区白土生产力和水稻产量水平。设置2种耕作方式(旋耕和翻耕)及3种施肥措施(单施化肥、化肥+有机肥、化肥+秸秆还田),通过大田定位试验研究不同耕作方式与施肥措施对白土稻田土壤理化性质、水稳性团聚体分布以及水稻产量的影响。结果表明,相较于旋耕,翻耕降低0—10cm土层土壤养分含量,而使10—20cm土层有机质、全氮、有效磷和速效钾含量分别提高3.2%～8.8%,4.5%～9.2%,5.2%～8.2%和8.3%～17.7%。增施有机肥或秸秆还田使土壤有机质和速效钾含量较单施化肥处理分别提高1.3%～8.6%和4.1%～21.1%。翻耕方式下10—20cm土层土壤容重较旋耕降低14.4%～19.5%,土壤大团聚体比例在0—10,10—20cm土层则较旋耕分别降低3.0%～5.4%和3.5%～9.7%;在翻耕的基础上增施有机肥或秸秆还田土壤容重较单施化肥降低2.1%～6.6%,大团聚体比例则提高2.8%～8.4%。翻耕有利于水稻产量的提高,较旋耕的增产幅度在11.7%～18.0%,增施有机肥或秸秆还田使水稻产量提高1.7%～7.5%。因此,江淮地区连续多年旋耕的白土田进行适宜翻耕结合秸秆还田或增施有机肥可改善0—20cm土层土壤理化性质,有利于水稻产量的提升。

Effects of Tillage and Fertilization on Physicochemical Properties of Albic Soil and Rice Yields in Jianghuai Region

Albic soil with continuous rotary tillage has resulted in some problems, including shallow plough layer, sticky and tight subsoil and unbalanced nutrient distribution. In order to explore suitable tillage and fertilization modes in paddy fields to improve albic soil productivity and rice yield in Jianghuai region, a field experiment was carried out to study the effects of different tillage and fertilization practices on physicochemical properties, the distribution of water-stable aggregates and rice yields in albic soil. The treatments consisted of two tillage practices (rotary tillage and conventional tillage) and three fertilization modes (chemical fertilizer, chemical fertilizer+organic manure, chemical fertilizer+straw returning). The results showed that compared to rotary tillage, conventional tillage reduced the soil nutrient contents of 0-10 cm soil layer, but increased the contents of organic matter, total nitrogen, available phosphorus and available potassium in 10-20 cm soil layer by 3.2%~8.8%, 4.5%~9.2%, 5.2%~8.2% and 8.3%~17.7%, respectively. The amendment of organic manure or straw returning increased the contents of soil organic matter and available potassium by 1.3%~8.6% and 4.1%~21.1%, respectively. The bulk density in 10-20 cm soil layer under conventional tillage was 14.4%~19.5% lower than that of rotary tillage, and the percentages of soil macro aggregates under conventional tillage were lower than rotary tillage by 3.0%~5.4% in 0-10 cm soil layer and 3.5%~9.7% in 10-20 cm soil layer, respectively. Under conventional tillage, the amendment of organic manure or straw returning reduced soil bulk density by 2.1%~6.6% and increased the percentage of macro aggregate by 2.8%~8.4%, compared to chemical fertilizer application. The rice yield under conventional tillage was 11.7%~18.0% higher than rotary tillage, and the amendment of organic manure or straw returning enhanced the rice yield by 1.7%~7.5%. Therefore, in albic soil with continuous rotary tillage in Jianghuai region, conventional tillage combined with straw returning or organic manure amendment was beneficial to improve soil physical and chemical properties of the 0-20 cm soil layer and increase rice yield.