Soil acidity and plant nutrient management

Scope and method of study. The study examined the effectiveness of manure compared to lime in reducing aluminum toxicity and increasing plant growth, investigated the contributions of pH increase, organic materials and phosphorus addition to the alleviation of aluminum toxicity associated with manure application and studied the effect of alum-treated manure on properties of an acid soil and plant growth. Nutrient management using GIS was also included in this study. Pot experiment was conducted by growing winter wheat ( Triticum aestivum L.) sensitive to Al toxicity. Wheat growth was correlated with soil extractable Al, feedlot manure, poultry litter and alum-treated poultry litter application rates. Lab incubation experiment also performed by applying feedlot manure to soil, adjusting soil pH and adding phosphorus to investigate the overall effect, pH effect and phosphorus effect on the reduction of extractable aluminum associated with manure application. The effect of organic materials on reducing extractable aluminum was calculated. ArcView GIS was used to map buffer zones, soil nutrient distributions and fertilizer recommendations.; Findings and conclusion. Feedlot manure and poultry litter increased soil pH, reduced CaCl2 extractable Al and exchangeable Al in soil although their effects per unit mass were not as high as lime. However, at the same aluminum level, poultry litter was more effective on the increase of wheat growth than feedlot manure and lime. Animal manure applied to acid soils not only provided plant nutrients but also reduced aluminum toxicity. Organic binding with Al played a more important role than pH increase and phosphorus addition did associated with manure application. Application of alum-treated poultry litter had the potential to increase soil NH 4-N by prevent NO3-N formation but was not as efficient in supplying P nutrient and reducing Al toxicity as untreated poultry litter. The digital maps of nutrient distributions, crop arrangement, and fertilizer recommendations provide useful tools for farmers and the methodology in this study can be used in other farms.