玉米生长期土壤抗蚀性特征及其影响因素分析

土壤抗蚀性是评定土壤抵抗土壤侵蚀能力的重要参数之一,为了摸清川中丘陵区土壤抗蚀力变化特征,该文通过野外调查与室内分析相结合方法,开展玉米生长期土壤抗蚀性特征及其影响因素研究。研究结果表明:玉米季各生育期土壤抗蚀指数随着土粒浸水时间延长均呈下降趋势,0～20 cm土层抗蚀指数均大于20～40 cm土层。各生育期土壤抗蚀指数总体特征表现为:苗期-小喇叭口期土壤抗蚀指数呈较小的增长趋势,小喇叭口期-抽雄期土壤抗蚀指数呈大幅增加并于抽雄期达最大,抽雄期-成熟期土壤抗蚀指数却呈小幅下降趋势。随玉米生育期推进,土壤抗蚀性总体表现为:抽雄期成熟期大喇叭口期小喇叭口期苗期。玉米植株对土壤抗蚀性的增强效应主要体现在大喇叭口期-成熟期,0～20 cm土层土壤抗蚀性增强效应明显优于20～40 cm土层。土壤抗蚀性与土壤容重和2 mm水稳性团聚体呈显著正相关,与土壤有机质含量和0.25 mm水稳性团聚体分别呈极显著正相关和负相关,与含根量、根系表面积、根系体积和总根长呈极显著正相关。研究成果为区域水土流失防治措施配置及土壤侵蚀预报提供理论依据。

Soil anti-erodibility and analysis of its influencing factors during growing stages of maize

Abstract: Soil anti-erodibility is an important parameter to evaluate the soil resistance to erosion ability. Severe soil erosion on sloping farmland in hilly areas of Sichuan has resulted in deterioration of soil quality= and therefore has an adverse impact on the sustainable agricultural development. To clarify the nature of soil anti-erodibility, a field experiment was conducted to study the characteristic of soil anti-erodibility and the factors that influence it during the growing stages of maize. Soil anti-erodibility index was selected to evaluate the soil resistance to erosion in different growing stages of maize in purple soil areas. At the same time, based on soil physico-chemical properties and maize root parameters, the influencing factors of soil anti-erodibility were analyzed. The results indicated that the soil anti-erodibility index decreased with increasing soaking time during the growth period of maize. The soil anti-erodibility indices of the 0-20 cm soil layer were higher than those of the >20-40 cm soil layer. The soil anti-erodibility index varied greatly during the growth period of maize. The soil anti-erodibility index increased slightly from seedling to small flare stage, increased significantly from small flare stage to anthesis stage, and decreased gradually from anthesis stage to maturity stage. Soil anti-erodibility showed a rising-and-falling trend with the development stages of maize, such as tasseling stage, mature stage, big flare stage, small flare stage and seedling stage. Enhancing effect of maize on soil anti-erodibility was stronger from the big flare stage to mature stage, and the enhanced effect of soil anti-erodibility in the 0-20 cm layer was better than that of >20-40 cm layer. There was a significant, positive correlation between soil anti-erodibility and soil bulk density and >2 mm water-stable aggregates. Maize roots played a key role in soil and water conservation. Therefore, it has aroused the attention of the domestic and overseas scholars. There were very significant positive correlations between soil anti-erodibility and soil organic matter, root number amount, root surface area, and root volume. So the maize roots played an important part in soil reinforcement in the different growing stages. However, there was very significant negative correlation between soil anti-erodibility and < 0.25 mm water-stable aggregates. The results suggested that soil anti-erodibility was poor in the seedling stage and small flare stage, and soil anti-erodibility was greatest in the anthesis stage. It is possible to enhance soil anti-erodibility of sloping farmland by rational intercropping in the seedling stage and small flare stage in hilly areas of Sichuan. At the same time, some measures would be conducive to increase soil anti-erodibility, including the improvement of soil physico-chemical properties and cultivation of maize varieties with strong root systems. This study provides a reliable theoretical basis for optimizing the configuration of soil conservation measures and the prediction of soil erosion.