Abstract:In order to explore the effect of soil water, temperature and nutrient characteristics under autumn tillage with mulching practices on the growth and yield of dryfarming potato, a field experiment was conducted to study different tillage with mulching measures after the autumn crop harvest in potato cultivation of southern Ningxia between 2013 and 2016. Soil water at 0~200cm layer, topsoil temperature at 0~25cm layer and soil nutrient content at 0~40cm layer, the growth and yield of potato were investigated. The results showed that the tillage methods, mulching measures, and their interactions had highly significant effects on the soil water storage during the potato sowing season, and treatments of notillage with straw mulch and subsoiling with straw mulch had the best effect of soil conservation. Notillage with straw mulch and subsoiling with straw mulch significantly increased the mean soil water storage by 14.4% and 14.7%, respectively, compared with the plowing with no mulch. The tillage methods, mulching measures, and their interactions had significant effects on the soil water storage, and the improvement effect of subsoiling with straw mulch on soil water was the best. Subsoiling with straw mulch significantly increased the mean soil water storage by 207% compared with the plowing with no mulch. The tillage methods, mulching measures, and their interactions significantly affected topsoil temperature, while a reduction in their effect as the growing season of potato was advanced. Among the tillage methods, the film mulch plots increased the mean topsoil temperature by 3.6℃, whereas the straw mulch plots reduced the temperature by 1.4℃ during each potato growing season. Over the three years of the autumn tillage with mulching experiments, the interactions between tillage methods with mulching measures highly and significantly affected the indexes of soil nutrient. Among all of the treatments, the higher mean soil organic matter, total N, alkalyzableN, available P and available K at 0~40cm layer was obtained in the notillage with straw mulch and subsoiling with straw mulch treatments and the minimum in the PT×NM treatment. Among the tillage methods, the warming effect of subsoiling with film mulch treatment significantly promoted the growth of potato in the early stage, while the higher temperature during the later stage in subsoiling with film mulch was not conducive to the reproductive growth of potato. However, the stable temperature and cooling temperature effects of subsoiling with straw mulch treatment significantly promoted the growth of potato in the later growth period. Among all the treatment combinations, the mean potato total yields and net incomes under the subsoiling with straw mulch and notillage with straw mulch were the highest. The mean potato total yield was significantly increased by 49.4% and 383% under the subsoiling with straw mulch and notillage with straw mulch treatments, respectively, and the mean net income was increased by 129.1% and 103.3% when compared with plowing with no mulch treatment. However, the best marketable tuber rates were obtained under subsoiling with film mulch and subsoiling with straw mulch, which were significantly higher by 18.4% and 16.2% than that of plowing with no mulch. Taking together, in consideration of soil environmental and economic feasibility, it was recommend that the notillage and subsoiling combined with straw mulch practice was a more favorable practice for improving soil water, temperature and nutrient environment and potato productivity, and it had certain practical values in dryland potato cultivation of southern Ningxia.
