Effect of Organic and Inorganic Amendments on the Phytoavailability of Phosphorus to Corn (<i>Zea mays</i>)

A pot experiment was conducted to investigate the effect of cow manure, city waste, chicken manure and TSP on the growth of corn (Zea mays) and phytoavailability of phosphorous (P) in soil. An air dried sandy loam soil was mixed with different amendments at rates equivalent to 0, 200, 400 and 800 mg P kg^–1 soil based on total P. The plant height and leaf number increased in the plants grown in amended pots compared to control pot. The dry weight of shoots and roots in the control pot were 14.3 and 2.8 g, respectively. The shoot dry weights of corn increased from 43.8 to 76.6 g with the cow manure, 27.8 to 38.7 g with the city waste, 48.4 to 68.2 g with the chicken manure and 30.2 to 32.2 g with the TSP amendments when the P addition rates increased from 200 to 800 mg P kg^–1 soil. Similar effects of these amendments and their rates were also found in the case of roots dry weights production. Phosphorus concentration in the plant parts increased with the P application from different amendments but the increase was higher with the TSP fertilizer and lower with the city waste amendments. Olsen P (measured after the plant harvest) increased with P application rates. The extractability of Olsen P from different amendments increased in this order: city waste < chicken manure < cow manure < TSP. Olsen P was strongly related with both shoot and root P concentration of corn (r = 0.910, p = 0.000), indicate suitability of Olsen P to predict plant available P. These results imply that cow manure and chicken manure could be recommended to use in the agricultural field for producing optimum yield