Research On The Amelioration Of Acid Soils In The Hot Zone By Different Biomass Materials

In recent years, soil acidity become more and more serious along with acid deposition and acid rain having frequently occurred in hot zone, which resulting in soil leanness and activation of heavy metal elements. Soil acidification is becoming an important factor which influence crop production. The amelioration effects of acid soil were investigated by incorporating various four plant materials including coconut chaff,rubber wood sawdust, banana pesudostem, bagasse and four biochar materials which is made from the four kinds of plant materials with different addition amount (1.5%,4.5%,7.5%) into the typically brick-red acidic soil deprived from granite with incubation method and spot experiment. The research shows the results as follows:Plant materials which added into acidic soils can affect on soil pH in various degrees. Among them, the effect of enhancing the pH value of the banana pesudostem and rubber wood treatment are better than coconut husk and bagasse treatment. The degree of amelioration of the soil acidity by the plant materials was found to depend on the ash alkalinity and N content of the materials. The soil final pH was positively correlated with ash alkalinity (r2=0.91), nitrogen content (r2=0.88) and a salt ion content (r2=0.92) of plant materials. Besides chaff treatment, all other materials could decrease soil acidity and exchangeable aluminum content; four kinds of plant material can increase soil exchangeable base and cation exchange capacity, and each base cations in soil due to varies salt nutrients content from plant material; soil organic matter increases with increasing the addition of the plant material which was added into soil; banana pesudostem could increase K content significantly in soil; available phosphorus content in other treatment is lower than that of control besides banana pesudostem;variety in nitrogen content decreased with increasing adding amount of material, the available N content between banana pesudostem treatment and control had no differences.Biochar which was added into acid soil could improve soil pH at different degrees, banana pesudostem biochar treatment is superior to coconut shell biochar, charcoal biochar and glue sugarcane charcoal for the rise of soil pH. Final pH of soil showed a significant positive correlation with ash alkalinity (r2=0.99), nitrogen content (r2=88) and base cations content (r2=97) in the biochar. Four kinds of biochar can increase soil exchangeable base and cation exchange capacity. All of the banana pesudostem biochar treatments, coconut shell biochar treatment of4.5%and7.5%addition and rubber wood biochar of7.5%addition made soil base supersaturated; banana pesudostem biochar, coconut shell biochar and rubber wood biochar could reduce soil EA and exchangeable aluminum; soil organic matter increase with increasing the amount of biochar;coconut shell biochar and banana pesudostem biochar can greatly enhance the available potassium content; available phosphorus content increase with increasing the amount of biochar; banana pesudostem biochar treatment's available nitrogen content was significantly lower than that of control, the differences between the other treatments and the control is not significant.We conduct an experiment about cabbage growth in pots, the result reflects that cabbage fresh weight of the single banana pesudostem biochar, the single application of lime, the mixed application of banana pesudostem biochar-Coconut charcoal, banana pesudostem biochar-rubber wood biochar, banana pesudostem biochar-lime were significantly improved more than that of control. The single biochar application and the mixing biochar treatment are able to reduce soil acidity; the effective nutrient content and organic matter content of the soil with mixed application of biochar were higher than the control and lime.