耕作方式对连作高粱产量及土壤水分与有机碳含量的影响

Effect of Tillage Methods on Yield and Soil Water and Organic Carbon Content of Continuous Cropping Sorghum

为缓解连作障碍,改善土壤,保证高粱原粮生产量和农业可持续发展。2019-2020年,在山西农业大学高粱研究所东白试验基地开展高粱连作长期定位试验,研究休闲期传统耕作、免耕、秋旋耕、秋深松、秋深耕、春深耕等不同耕作方式对连作高粱土壤水分、有机碳及产量的影响,旨在寻求连作高粱产量提升的适宜耕作方式和时间,及其蓄水保墒固碳增产机理,为高粱的稳定生产提供栽培技术及理论依据。结果表明,休闲期耕作可增加连作高粱各生育时期0~20 cm土壤有机质含量,增加颗粒有机碳、轻组有机碳、重组有机碳、易氧化有机碳和可溶性有机碳含量;增加播前0~100 cm土壤蓄水量0.72~46.52 mm和各生育时期0~100 cm土壤蓄水量,且播前水分可延续用至拔节期,中后期由于降水多仍有效果;可增加产量4.75%~23.67%,增加生育期水分利用效率19.09~29.19 kg/(hm^(2)·mm),尤其秋深耕耕作方式增加更明显。相关分析表明,连作高粱产量与土壤水分、有机质含量显著正相关;底墒较高时,产量与生长前期土壤水分关系更密切;底墒较低、中后期降水较多时产量与中后期土壤水分关系更密切。总之,连作高粱在休闲期秋深耕,利于增加有机碳含量,利于蓄水保墒,且水分延用至拔节期,从而提高产量和水分利用效率。

In order to alleviate continuous cropping obstacles and improve soil,to ensure sorghum raw grain production and sustainable agricultural development.The long-term located experiment of continuous cropping sorghum was carried out in Dongbai base of Sorghum Research Institute of Shanxi Agricultural University from 2019 to 2020 to study the effects of tillage methods(traditional tillage,no tillage,rotary in autumn,subsoiling in autumn,deep ploughing in autumn,deep ploughing in spring)in fallow period on soil moisture,organic carbon content and yield of continuous cropping sorghum,aiming to find the suitable tillage method and time for increasing the yield of continuous cropping sorghum,and the mechanism of water conservation,carbon sequestration and yield increase so as to provide cultivation techniques and theoretical basis for the stable production of sorghum.The results showed that tillage in fallow period increased the soil organic matter in 0-20 cm soil layer in each growth period of sorghum,and increased the content of particulate organic carbon,light fraction organic carbon,heavy fraction organic carbon,readily oxidized organic carbon and dissolved organic carbon,and also increased soil water storage in 0-100 cm soil layer by 0.72-46.52 mm before sowing and soil water storage of 0-100 cm soil layer at each growth period,furthermore,the soil water before sowing continued to be used until jointing stage and it still was very effective even though much precipitation in the middle and late stages.Meanwhile,tillage in fallow period increased the yield by 4.75%-23.67% and the water use efficiency in the growth period by 19.09-29.19 kg/(ha·mm),especially the increased effect of deep ploughing in autumn was more significant.The correlation analysis showed that the yield of continuous cropping sorghum was significantly positively correlated with soil moisture and organic matter content,and the yield was more closely related to the soil moisture in the early growth stage if the base soil moisture level was higher and more closely related to the soil moisture in the middle and late stages if the base soil moisture level was lower and the precipitation in the middle and late stages was more.In short,deep ploughing in autumn of continuous cropping sorghum during fallow period was beneficial to increase the organic carbon content and promote the soil moisture conservation so that the moisture continued to be used at jointing stage,thereby increased yield and water use efficiency.