为明确砂姜黑土适宜的耕作深度,构建砂姜黑土合理耕层,本研究以砂姜黑土区多年大田定位试验为基础,设置4个耕作深度处理：深松30 cm(S30)、深松40 cm(S40)、深松50 cm(S50)和深松60 cm(S60),以旋耕(RT,耕作深度为15 cm)为对照,研究不同耕作深度对土壤孔隙、土壤呼吸速率、夏玉米根系生长、物质积累、养分吸收和产量的影响。研究结果表明,增加耕作深度不仅可以改善土壤孔隙状况,优化土壤环境质量,还可以促进夏玉米根系生长、植株物质积累和养分吸收,进而提高夏玉米籽粒产量。随着耕作深度的增加,土壤孔隙状况随之不断改善,但夏玉米籽粒产量、物质积累和养分吸收却呈现先增加后降低的趋势。4个耕作深度中,以深松50 cm的改土和增产效果最佳。与旋耕相比,深松50 cm处理40-50 cm土层的土壤孔隙度和孔隙面积分别增加27.8%和24.8%,土壤呼吸速率增加63.7%,夏玉米根系干重密度、植株干物质积累量、氮素积累量、磷素积累量和钾素积累量分别增加89.0%、13.2%、15.5%、20.7%和9.0%,夏玉米籽粒产量提高11.0%。因此,对夏玉米生产而言,砂姜黑土的耕作深度不宜超过50 cm。
英文摘要:
In order to determine the suitable tillage depth and establish a reasonable topsoil of Lime Concretion Black Soil, a multi-year experiment with four tillage depths of subsoiling [30 cm (S30), 40 cm (S40), 50 cm (S50) and 60 cm (S60)] and rotary tillage (RT, 15 cm) as the control was carried out to study the effects of different tillage depths on soil porosity, soil respiration rate, and root growth, biomass accumulation, nutrient absorption and grain yield of summer maize. The results showed that, the increase of tillage depth could not only improve the soil porosity and soil environmental quality, but also promote the root growth, biomass accumulation and nutrient absorption of summer maize, so as to improve the grain yield of summer maize. With the increase of soil tillage depth, the soil pore condition improved continuously, but the grain yield, biomass accumulation and nutrient absorption of summer maize increased first and then decreased. Among the four tillage depths, the S50 treatment was the best. Compared with rotary tillage, the soil porosity and surface area of soil pores at 40-50 cm soil layer under S50 treatment increased by 27.8% and 24.8% respectively, the soil respiration rate increased by 63.7%, the root mass density, dry matter accumulation, nitrogen accumulation, phosphorus accumulation and potassium accumulation of plant increased by 89.0%, 13.2%, 15.5%, 20.7% and 9.0% respectively, and the grain yield of summer maize increased by 11.0%. Therefore, the suitable tillage depth should not exceed 50 cm for summer maize production in Lime Concretion Black Soil.
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