Effects Of Self-sown Grass On Soil Physical Properties And Microbial Diversity Of Pear Orchard In Yellow River Delta

In recent years, a large number of domestic and foreign research found that orchards are grassing in the world’s advanced countries, but only Chinese farmers are still weeding. The major reasons are that the intensive farming culture in Yellow River of 3000 years, the concepts of weed competition for water and fertilizer with fruit, and everyone has little arable land and so on. To effectively solve the issue that the grass is disaster or friend in orchard and promote the application of orchard grass in China which is a modern soil management model, reports on orchard grass in domestic research increased significantly in recent years. The golden pear [Pyrus pyrifolia(Burm.f.).cv.Nakai] and the orchard soil which had self-sown grass for 0,4, 6 and 9 years, respectively were taken as experimental materials. Soil bulk density, porosity, conductivity, PH value, moisture content, Microbial biomass carbon and nitrogen, bacteria characteristic of genetic diversity, microbial respiration, active microbial biomass, total amount of fatty acid(plfa), the utilization of carbon and other related indicators in 0-20 cm soil layer were determined, and the changes were analyzed. To provide the scientific basis for theoretical support and promote the use of orchard grass fertility technology, and enrich the orchard soil microbial diversity theory, the effects of self-sown grass on soil physical properties and microbial diversity of pear orchard in yellow river delta were studied. Main research results are as follows:1. Natural grass for different years of the Yellow River delta pear orchard Soil bulk density, porosity, conductivity, PH value, moisture content in Plow layer were significant differences between the groups. The results showed that multiple years of grass growing significantly enhanced soil porosity and reduced soil bulk density and conductivity, suggesting that permission of natural grass growing in the orchard could reduce soluble salts in soil, and it had no influence on water content in the soil.2. Natural grass for different years of the Yellow River delta pear orchard Microbial biomass carbon and nitrogen, bacteria characteristic of genetic diversity in Plow layer were significant differences between the groups. The results showed that grass growing also increased the microbial mass C and N. By employing the PCR-DGGE and sequencing technology, we found that the majority of the increased bacterial fall into the species that cannot be cultured.3. Natural grass for different years of the Yellow River delta pear orchard microbial respiration, active microbial biomass, total amount of phospholipid fatty acid(plfa) in Plow layer were significant differences between the groups. The results showed that the grass four years of microbial activity, microbial biomass and microbial activity of total phospholipid fatty acids and was not significant with clean cultivation, but the grass 6-9 years of treatment microbial respiration, activity, active total microbial biomass and microbial phospholipid fatty acids were 2.26 times, 2.75 times, 1.86 times and 1.57 times of clean cultivation, the difference was significant or very significant, but the difference of grass six and nine years between the two treatment is not significant. Rather than the clean cultivation, grass treatment has little effect on microbial phospholipid fatty acid(PLFA) species, no significant differences between each other.4. Natural grass for different years of the Yellow River delta pear orchard microbial the utilization of carbon in Plow layer were significant differences between the groups. The results found by 6 categories of 31 kinds of carbon source showed that grass growing also improved carbon utilization capacity and the most significant effect displayed after 4 years implementation and the more balanced utilization of six carbons was simultaneously achieved during this process.