Effects And Mechanism Of Biomass Materials On Amelioration Of Acidic Tea Garden Soil

Acidification of tea garden soil is an increasing cornern at present. Over-acidification of tea garden soil not only reduces the yields of tea, but also endangers human health and leads to other ecological problems. Therefore, there is an urgent need to find economic, effective, and applicable measures to mitigate the acidification of tea garden soil. Currently, modern agricultural activitiy generates tremendous of biomass material. Incomplete and unreasonable uses of those biomaterials are in fact a waste of resource and have caused serious environmental problems. In this study orientation research, indoor incubation experiment and field test were adopted to survey the situation and trend of tea garden soil acidification in Jiangsu Province. Based on this, we explored the application of biomass materials to regulate the pH of tea garden soil, investigated the mechanism of the amelioration of acidic soil by the biomass, and seeked economical and practical, simple operation method to maintain the suitable acidity of the tea garden soil. Meanwhile, we selected typical tea garden in Jiangsu into field trials. The research objective is to promote reasonable zoning and scientific management of tea production, as well as provide the basis for further adjusting the agricultural structure. Following results are generated in this research:By positioning the research, it was illustrated that:serious acidification existed in typical tea garden soils in Jiangsu in2011. The pH of11Jiangsu tea garden soils that were surveyed was lower than the optimum pH value for of tea tree growth which is5.5. The pH of nearly82%of the tea garden soils was below the range limit pH suitable for tea tree growth which is4.5,64%of which is below4.0. There was an accelerating trend of acidification rate over the past decade. In addition, within observation period (2003-2011), the average pH of tea garden soils in Jiangsu province showed a decreasing trend.Based on the analysis of the acidification situation and trend of tea garden soils in Jiangsu province,7different biomass materials were selected and applied tea garden soils to explore their amelioration effects.3different tea garden soils were tested in both indoor incubation experiments and field trials. The results indicated that seven different biomass materials all increased the pH of acidified soil. At the same time, nutrient characteristics of the soils were improved and the aluminum concentrations were reduced. However, the extent of amelioration effect varied depending on the types of biomass materials. Under the same conditions, the lower of tea garden soil, the higher of increased pH after application of biomass materials. Meanwhile, the increased pH value of acidic tea garden soils after using seven kinds of biomass materials from high to low in order was:cow dung> commercial organic fertilizer> straw compost> rice straw> biological straw carbon> corn straw> biogas residue. In addition, under the same conditions, the contents of soil exchangeable acidity, exchangeable aluminum, total soluble aluminum, and total monomeric aluminum decreased significantly after biomass materials treatment. Among different biomass materials, the amelioration effects of cow dung, straw compost and commercial organic fertilizer were more prominent than the others. The straw carbon, cow dung, straw compost and commercial organic fertilizer were more effective than other materials in increasing the exchangeable cation contents and the degree of soil base saturation, as well as the soil cation exchange capacity and soil organic matter content. Comprehensive analysis of the amelioration effects of selected seven kinds of biomass materials, overall improvement of cow dung, straw compost and commercial organic fertilizer were better than other materials.Finally, the amelioration effects of commercial organic fertilizer and biological straw carbon applied to two different acidic tea garden soils were respectively examined in field test. The results showed that applying two kinds of biomass materials not only increased the pH of two acidic tea garden soils, but also significantly reduced the contents of tea garden soil exchangeable acidity, exchangeable aluminum (P<0.01). Meanwhile, soil exchangeable capacity and soluble aluminum in the acidic tea garden were also affected. The application of biomass materials also improved soil organic matter and nutrient content. The actural improvement effects depended on acid strength of the tea garden soils and vary types of biomass material.