A Research And Application Of Acidic Soil Conditioner Based On Biomass Ash

Red soil is one of the important soils in southern China. Soil acidification due to environmental pollution in recent years has seriously restricted the sustainable development of agriculture in this area. Extensive use of lime to red soil gradually shows its negative effects and as a non-renewable resource, the application prospects are also restricted. With the development and utilization of biomass energy and more biomass power plants, the generation of solid alkaline wastes such as biomass ash and environmental stress caused by random stacking or landfill are increasing year by year. While more attention is paid to biomass ash utilization, the research of biomass ash used to deal with soil acidity has been rare. Therefore, it is of great significance to study the effect of biomass ash utilization on acid soil and its utilization technology.We studied the applications of three kinds of soil amendments which was biomass ash, E and F, and their different proportions to red soil and obtained a formulation by using soil cultivation and field experiments. We used E and F to represent the other two soil amendments to keep the new kind of soil conditioner secret. The effect of the soil amendments on red soil acidity, fertility and peanuts growth were also investigated. The results were as follows:(1) Compared with CK, the influence of biomass ash, E and F on red soil acidity and nutrients was obvious. Biomass ash, E and F increased soil pH and decreased the exchangeable Al3+ in the order of E> F> biomass ash. During the cultivation, the soil pH and the exchangeable Al3+ was significantly affected by the amount of E and F while the effect of the amount of biomass ash on soil acidity was significantly different at an early stage. Biomass ash, E and F significantly affected soil nutrient. In addition, there were some differences between amendment type and application rate. The use of E significantly increased soil available nitrogen and phosphorus. Biomass ash application increased soil available phosphorus and potassium and F improved soil available phosphorus. All three amendments significantly increased soil cation exchange capacity and exchangeable Ca2+, with an increasing trend with the amount of soil amendments. E and F applications had no significant impact on soil exchangeable K4, while for soil exchangeable K+, biomass ash treatment had an increasing trend with the application rate. The difference between biomass ash treatment and control was significant, except for the treatment with 1500kg·hm-2. No trends were observed for the effects of three amendments on soil exchangeable Mg2+ and exchangeable Na+(2) According to the characteristics of soil amendments and their different effects on soil acidity and nutrient, we mixed the three amendments at certain ratios to study their effects on soil acidity and nutrient. The mixtures are the combinations of biomass ash and E, biomass ash and F, and E and F, with the ratios al, a2, and a3, respectively. We used al, a2 and a3 to represent the ratios to keep the new kind of soil conditioner secret.The results showed that the mixed amendments could significantly improve soil pH and reduce soil exchangeable Al3+. The combination of biomass ash and F significantly improved the soil pH and reduced soil exchangeable Al3+ at an early stage. Moreover, the differences between different ratios were not significant. There were significant differences between the mixed amendments and soil available nutrients. The soil available nitrogen had no significant relationship with the mixed amendments. The differences between soil available phosphorus and different ratios were different. The combination of biomass ash and E had no significant difference between proportions and soil available phosphorus, while the mixed amendment of biomass ash and F had. When the combination ratio of apatite and E reached a2, the soil available phosphorus was up to 19.60mg·kg-1as the maximum. The soil potassium content was the highest when the combination of biomass ash and E ratio was al, reaching 198.75mg·kg-1; soil potassium content was 196.25mg·kg-1 when the combination of E and F ratio got to a3; and it had no difference with the ratio of a2.The influence of mixed amendments on soil cation exchange capacity and base cations were complicated. The combination of biomass ash and E, and E and F increased soil cation exchange capacity and soil exchangeable Ca2+. The soil cation exchange capacity and soil exchangeable Ca2+ content were the highest when the ratio of biomass ash and F was al. They were 16.50cmol·kg-1 and 3.61cmol·kg-1 respectively. No relationship was observed between mixed amendments and soil exchangeable Mg24. The combination of biomass ash and E increased soil exchangeable K+ and soil exchangeable Na+, when the ratio was al, with the soil exchangeable K+ 0.61cmol·kg-1.When the combination ratio of biomass ash and F reached al, its influence on soil pH was better than the combination of biomass ash and E, E and F, with their ratios al and a2 respectively. They increased soil cation exchange capacity, soil available potassium and soil available phosphorus content. So the best combinations were biomass ash and E, biomass ash and F, and E and F, with their ratios were al, al, and a2, respectively.(3) Based on the experimental results and the characteristics of the soil amendments, we made a new kind of soil amendment named Z, which was the combination of biomass ash, E and F with the ratio a4. The results showed that Z increased soil pH value and decreased soil exchangeable Al3+ with a long duration. The application of Z to peanut soil increased soil alkali-hydrolyzable nitrogen, soil rapidly available phosphorus, soil available potassium, soil cation exchange capacity, soil exchangeable Ca2+ and soil exchangeable K+. However, it had no significant effect on soil exchangeable Mg2+, soil exchangeable Na+, soil total nitrogen, total phosphorus, total potassium and organic matter.(4) Amendment Z significantly improved peanut plant height, branch length, number of branches, fresh weight per plant, pod fresh weight and hundred kernel weight, and was conductive to the peanut production. Amendment Z improved peanut production. The peanut plant height, branch length, number of branches, fresh weight per plant, pod fresh weight and hundred kernel weight were 40.90cm.45.00cm,11.33,197.52g,59.03g, and 57.56g, respectively. The peanut yield increased by 26%.(5) Z improved the red soil acidity and soil fertility, promoted peanut growth, and improved peanut production. So far 50 tons of Z has been produced and applied in red soil in Jiangxi and Anhui.