EFFECT OF PARTIALLY ACIDULATED ROCK PHOSPHATE ON GROWTH AND YIELD OF MAIZE IN A CALCAREOUS SOIL COMPARED WITH SOME TRADITIONAL PHOSPHATE FERTILIZERS

Two experiments were conducted to study the impact of adding partial acidulated rock phosphate in comparison with traditional phosphate fertilizers. First experiment was conducted to study Kinetics of P release from partially acidulated pock phosphate (30, 40, 50, 60, and 70%) or from TSP and SSP at 80 kg P ha-1. The results showed that the release of phosphorous from acidified rock phosphate was characterized by 1st order kinetics with high (R2) and lowest SEe. TSP gave the highest quantity of soluble phosphate in aliquot compared to SSP. The 2nd experiment was a field one aimed to study the effect of partial acidulated rock phosphate on growth and yield of maize compared in comparison to TSP and SSP. The results showed that partially acidulated RP at 70% level was superior for all parameters of growth and yield of maize over all other treatments. The 70% partially acidulated gave the highest, plant dry matter, seed weight for individual plant, total plant seed yield, which was in value of, 332.20 gm.plant-1, 181.5 gm.plant-1 and 13.625 Mg.ha-1 respectively, but with no significant differences than 60%.therfore , 60% acidulation can be recommended under used management practices.

Effect of nutrient seed coating on the emergence and early growth of perennial ryegrass

Perennial ryegrass (Lolium perenne L.) seeds were coated with either lime, reverted superphosphate plus nitrogen as isobutylidene diurea (RSN), or partially acidulated rock phosphate plus sulfur (ESPARP). In one experiment emergence rates and total emergence were calculated by fitting Mitscherlich-type curves to the data and then conducting statistical tests on the three parameters found for each curve. There was a significant interaction between soil moisture and coating treatment for all three parameters. In a glasshouse experiment, the same coated and uncoated seed treatments were sown either in soil supplied with nitrogen, phosphorus and sulfur or in soil with nutrient deficiencies of either N, P, or S or NPS, and the early growth of the plants and their P and N uptakes were studied. The two nutrient-coated treatments (RSN and ESPARP) produced more tillers and dry matter yields of roots and shoots than did lime-coated or uncoated seed when grown in soils deficient in P, S or NPS. Nitrogen deficiency reduced yields of all plants, even those derived from RSN seeds. N uptake in the RSN treatment was not significantly different from the ESPARP treatment, indicating that the N in isobutylidene diurea was not available to the plant.