Relationship of physico-chemical properties and macronutrients indexing at soils of Ghora Bari area district Thatta, Sindh, Pakistan.

Abstract The field study was conducted to determine association of soil physico-chemical properties with plant available macronutrients in Taluka Ghora Bari district Thatta. A total of 100 soil samples were collected from different sites at 0-15 and 15-30 cm depths. The results showed that 66% were heavy in texture, while 34% were light textured. Soils were alkaline (82%), moderately saline (81%), highly calcareous (97%) in nature, and low (66%) in organic matter. Majority of soil samples (77%) were poor in total nitrogen, 51% were deficient in available phosphorus while exchangeable potassium was adequate. Clay correlated negatively with P and K and positively with N, while sand correlated positively with K. The effect of lime content on NPK was found negative, while soil pH was correlated negatively with P and K. Organic matter correlated highly significantly with N, P and K. Keyword: Physico-chemical properties, NPK status, nutrients index Ghorabari, Sindh Introduction The deficiency of nutrients has become major constraint to productivity and sustainability of soils. For the better growth of plants, amongst many other factors, thirteen essential elements are required to be present in soil in proper proportion and available form. Amongst these elements, nitrogen (N), phosphorus (P) and potassium (K) are categorized as macronutrients and are required in larger quantity than the other nutrients (Foth, 1984; Brady, 1990). The selection of proper rate of these plant nutrients is based on the knowledge of nutrient requirements of crop and nutrient supplying power of the soil. Results of physical and chemical properties are quality indicators which provide the information about capacity of soil to supply mineral nutrients. Crop yield depends on the available nutrient status of the soil (Khan