Regulation Of Soil Microflora In Farmland Under Different Fertilization Regimes

In this article, we studied farmland soil in De Zhou, Shandong province. We investigatedthe regulatory of farmland soil microflora in different fertilization treatments. In this experiment, we set six different treatments. Soil microflora was tested by high throughput sequencing, biolog microplate and gradient plate dilution culture method. Combined basic chemical indicators of soil, soil enzyme activities and crop yields, we analyzed the relationship between fertilization, soil microbes, soil enzyme, soil nutrients and crop yields. By this approach, these results can provide a theoretical basis for rational fertilization of agriculture. After experimental studies, we obtained the following conclusions:(1) The physical and chemical properties of the soil have changed significantly in two years. The concentration of soil nutrients (Total N, avilable P and avilable K) of 0.5M and NPKJ treatment was highest,0.3M and NPKI was higher than NPK and CK. The order of soil organism matter (SOM) in different treatments was:CK< NPK< 0.3M< 0.5M< NPKI< NPKJ, Soil pH:NPK<NPKJ<NOKI<0.3M<0.5M<CK. All these results suggest that manure supplement part of chemical fertilizer can have higher level soil nutrients, straw retum can have significant improvement on SOM, but was helpless in improving soil pH.(2) The effects on crop yield in different fertilization was significant. The total wheat yield of 0.3M treatment was 5.95% higher than that in NPK treatment,0.5M treatment was 0.94% lower than that in NPK treatment (P<0.01), and the total maize yield of 0.3M treatment is 1.27% lower than NPK treatment,0.5M treatment was 2.00% lower than that in NPK treatment (P<0.05). Then, manure supplement with 30% chemical fertilizer have a high yield in a low chemical fertilizer level.(3) Soil urease activity in NPK treatment was highest,0.3M and NPKJ was higher than that in NPKI,0.5M and CK was lowest. The order of soil invertase activity was NPKJ>NPKI>0.3M>0.5M>NPK>CK. The order of soil catalase activity was: CK>0.5M>0.3M>NPKJ>NPKI>NPK. These results illustrated that urease activity was proportional to chemical fertilizer, invertase activity was closely associated with straw returning, and the catalase activity was highly relative to manure fertilizer.(4) The number of microorganisms in CK treatment was lowest, and that in NPK was more than CK, NPKJ and NPKI was much higher,0.5M and 0.3M is highest. Then we knew that manure fertilizer can keep a high microorganism quantity and species.(5) Biolog results shows that chemical fertilizer can improve microbial metabolic activity, and manure fertilizer can highly improve the diversity of microbial metabolism. Besides, the function of the microbial community structure of 0.5M and 0.3M were extremely similar, NPKJ and NPKI obey the same regulation.(6) High throughput sequencing proved that manure and straw returning (inoculant) can effectively improve soil bacterial diversity, chemical fertilizer can bring a high bacteria abundance and a lower diversity. High percentage of replacing part of the chemical fertilizer and total amount of inorganic fertilizer plus straw teturning plus inoculant can improve fungal diversity, most inorganic fertilizer effect on bacterial richness index is larger, but little effect on fungal species diversity.