砂姜黑土耕作深度对夏玉米物质积累和养分吸收的影响

以多年定位试验为基础,设置深松30 cm(S30)、深松40 cm(S40)、深松50 cm(S50)和深松60 cm(S60)4个耕作深度处理,以旋耕(RT,耕作深度为15 cm)为对照,研究不同耕作深度对夏玉米物质积累和养分吸收的影响。结果表明,增加耕作深度通过改善土壤环境促进夏玉米根系生长、植株物质积累和养分吸收,进而提高子粒产量。随耕作深度的增加,土壤孔隙状况不断改善,夏玉米子粒产量、物质积累和养分吸收呈先增加后降低趋势。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41~50 cm土层的孔隙度和孔隙面积分别增加27.8%和24.8%,夏玉米根系干重密度、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%,子粒产量提高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。

Effects of Tillage Depth on Biomass Accumulation and Nutrient Absorption of Summer Maize in Lime Concretion Black Soil

To determine the suitable tillage depth 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 biomass accumulation and nutrient absorption of summer maize. The results showed that, the increase of tillage depth promoted root growth, biomass accumulation and nutrient absorption, and thus improved the grain yield of summer maize through improving the soil environmental quality. 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 RT, the soil porosity and surface area of soil pores at 41-50 cm soil layer under S50 treatment increased by 27.8% and 24.8% respectively, the root mass density, biomass 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, suitable tillage depth should not exceed 50 cm for summer maize production in Lime Concretion Black Soil.