免耕覆盖对宁南山区土壤物理性状及马铃薯产量的影响

宁南山区干旱频发、春旱突出,马铃薯播期土壤墒情不足、苗期干旱等问题,严重影响马铃薯的生长发育。该研究通过设置免耕条件下不同覆盖方式,以翻耕不覆盖为对照,研究不同覆盖耕作措施下土壤物理性状及马铃薯生长的影响。结果表明,与翻耕不覆盖相比,免耕覆盖可有效降低耕层土壤容重,改善土壤空隙状况,以免耕覆盖秸秆处理效果最佳。与翻耕不覆盖相比,免耕覆盖地膜和免耕覆盖秸秆处理可使0~20 cm土层5 mm机械稳定性团聚体含量显著增加,使20~40 cm土层2~5 mm机械稳定性团聚体的含量显著增加。免耕条件下不同覆盖方式能有效改善马铃薯生育期0~200 cm土层土壤水分状况,免耕覆盖地膜对作物生长前期土壤水分保蓄效果较好,免耕覆盖秸秆对作物生长中后期土壤水分状况的改善作用最佳。免耕条件下不同覆盖方式马铃薯植株株高、茎粗及地上部生物量均显著高于翻耕不覆盖,作物生育前期以免耕覆地膜处理效果最佳,中后期以免耕覆秸秆处理效果最明显。免耕覆秸秆处理的马铃薯产量和商品薯率最高,较翻耕不覆盖增产24.14%,商品薯率较翻耕不覆盖提高15.93%。可见,免耕覆盖秸秆措施具有良好的蓄水保墒效果,对马铃薯生长有利,其增产效果显著。该研究可为马铃薯高产高效栽培提供参考。

Effects of mulching with no-tillage on soil physical properties and potato yield in mountain area of southern Ningxia

Abstract: Droughts often occur, particularly in spring in southern mountainous region of Ningxia. The problem of soil water shortage and drought in seedling stage seriously influence the growth and yield of potato. In order to explore the effects of different ground surface methods combined with no tillage on soil physical characteristics, potato growth, and yield, a 3-year field experiment was conducted to study the effect of mulching with tillage on soil bulk density, elastic-stable aggregate, soil water, potato growth indexes, and yield in arid areas of southern Ningxia between 2013 and 2015. The field experiment consisted of the following 4 treatments: straw mulching with no tillage (NT+SM), plastic film mulching with no tillage (NT+FM), no mulching with no tillage (NT), and no mulching with conventional tillage (CT). The CT was used as the control. Our study results showed that the soil bulk density of the 0-40 cm soil layer under no tillage combined with mulching was decreased compared to CT, while the total soil porosity was greatly improved, and the NT+SM treatment was the best. During the study, the mean soil bulk density (0-40 cm) with NT+SM treatment was significantly (P<0.05) decreased by 10.22% when compared to CT treatment. The NT+SM, NT+FM, and NT treatments increased signi?cantly content of >5 mm elastic-stable macroaggregates by 29.16%-37.92% (P<0.05) at the 0-20 cm soil layer compared to CT. The amounts of >0.25~2 mm aggregates at the >20-40 cm soil layer in the NT+SM and NT+FM treatments were signi?cantly (P<0.05) increased by 40.50% and 67.07% than that of CT treatment, respectively. No tillage combined with mulching greatly improved soil water storage at 0-200 cm soil layer during the growing season of potato. The soil water storage of the NT+FM treatment was higher than the CT treatment at early stage of potato. However, the NT+SM treatment could significantly improve soil water content in later growth period. The application of mulching and tillage significantly promoted the growth of potato, and the plant height, stem diameter and aboveground biomass of potato under the different mulching methods with no tillage were higher than CT treatment. The NT+FM treatment significantly promoted the growth in the early stage of potato, while the NT+SM treatment significantly promoted the growth in later growth period. The potato yield and commodity rate improvements were the highest in the treatment of straw mulching with no tillage, and they were significantly (P<0.05) increased by 24.14% and 15.93% compared to CT treatment, respectively. In sum, the ground surface mulching with no tillage can not only effectively decrease soil bulk density, but also improve soil structure, and show the better ability of soil water conservation, therefore promoting the growth and yield of potato. Among all treatments, the straw mulching with no tillage was best for potato cultivation in the arid area of South Ningxia.