| In recent years, potato straw-mulching in sandwich model has developed a major mode of Fujian potato cultivation. The study suggested that it enhances the yield of potato and the proportion of the commodity potato, maintains higher soil water content and lower soil temperature oscillation, and improves the soil fertility. However, there is few of researches on soil character of potato straw-mulching in sandwich model. Thus, using the Zhongshu 3 as experimental material in this study, physical and chemical properties, enzyme activities and microorganism of soil at all growth stages of potato under straw-mulching in sandwich model were explored, and Illumina HiSeq sequencing method was used in the study of microorganism. The main results were as follows.1. In terms of yield characters, the yield, biomass and commodity rate of potato was increased by 9.68%,8.33% and 2.75%, respectively.2. In planting density of 60000 plants/hm2, soil moisture content of the seeding and squaring stages were increased by 6.1% and 2.5%, respectively; soil pH values of all growth stages was decreased by 1.9%-8.3%, and soil pH values was retained in the normal pH range form 5.2 to 6.4, under the straw mulching in sandwich model. It provide more suitable water and acidic environment to plant growth.3. In terms of the oxidoreductase activity, catalase(CAT) activity was increased by 1.8%,3.5% and 3.2% respectively at the seedling stage and the mid-and late of tuber growth period, and polyphenol oxidase(PPO) activity was decreased by 61.6% and 14.9% respectively at the seedling stage and the tuber growth mid-period, which prevent the root system form peroxide and improve the soil of humification. In terms of the hydrolytic enzyme activity, urease(URE) activity was increased by 12.6%-51.9% before the starch accumulation period, invertase(SUC) activity was increased by 16.6%,61.4% and 76.8% respectively at the mid-and late of tuber growth period and the starch accumulation period,acid phosphatase(ACP) was increased about 30% at all growth stages, which promotes the decomposition and transformation of SOM(soil organic), increasing soil fertility.4. By potato straw-mulching in sandwich model, the community structure of soil bacteria and fungus was changed to some extent, the change rate of community structure of soil bacteria was increased, diversity of soil microbial communities was enhanced at the seeding and tuber enlargement period, and diversity of soil fungal communities. But total abundance of the soil fungi that be identified was increased in the all growth stages, which rise 40.0%,45.8%,37.9% and 32.4% in squaring stages, tuber formation stage, tuber enlargement med-tern, and harvest. 5. By potato straw-mulching in sandwich model, enhancement of nitrogen-fixing bacteria and ammonifier increase the content of soil hydrolyzable N which was increased by 31.7% and 15.7% at the seeding and squaring stages, enhancement of denitrifying bacterium reduce the content of soil hydrolyzable nitrogen by 7.7%-44.8% at the tuber enlargement stages, and enhancement of phosphobacteria and acid formation bacteria form seeding stages to tuber formation stage and phosphate dissolving fungi at the latter of tuber enlargement period and starch accumulation period increase the content of soil available P which was increased by 0.6%-35.6%. The results also show enhancement of potassium bacteria, but the content of soil available K was reduced by 26.7%-62.8%. We think the reason is that the straw-return mode promotes the plant to potash absorption.6. By potato straw-mulching in sandwich model, pathogens were inhibited through increasing the fungus that have antimicrobial activity at the seeding, tuber enlargement and starch accumulation period, and the fungus that have antimicrobial activity rise 0.9 times and 1.2 times in the seeding and tuber enlargement; increasing the abundance of the Lecanicillium inhibit the growth and reproduction of nematodes. |
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