Environmental Effect of Hydroxyapatite Urea Application on Optimizing Urea Fertilizers for Wheat Plant

Abstract

This study was intended gradually release of nitrogen into the soil through the covering of urea pellets with hydroxyapatite and increase the wheat yield using zero valent iron spraying. Incubation trial was planed under different conditions (saturated and field capacity) for soil samples to study the performance of the use Hydroxyapatite urea on ammonium ionrelease for 63 days. A field trial was aimed to examine of hydroxyapatite urea and zero valent iron spraying on improved N-use efficiency, minimize nitrate leaching, and wheat productivity. Urea was used at two rates 80 and 100 % from recommended dose. Data of incubation trial observed that an increase of ammonium ion release with increase in time of incubation by using hydroxyapatite urea. Data of field trial observed that the release of nitrate was slower from hydroxyapatite urea soil than pellets urea, which reached 20 mg L-1 for urea pellets and 150 mg L-1 for hydroxyapatite urea at two weeks, respectively. Hydroxyapatite urea leads to minimize nitrate leaching into ground water. Also the results showed that the using of hydroxyapatite urea and zero valent iron individually or combined lead to increment in the yield of wheat compared to urea pellets. Yield of treatments was in the following order: urea100+Fe (11%) < hydroxyapatite urea100 (20%) < hydroxyapatite urea100+Fe (27%) compared to urea100 while urea80+Fe (10%) < hydroxyapatite urea 80 (23%) < hydroxyapatite urea 80+Fe (30%) compared to Urea 80. It is concluded from these data that controlled released urea fertilizer improved yield by 27%, and grain protein percentage 50% as compared to urea pellets. The highest increase for nitrogen uptake by wheat plant was observed by using hydroxyapatite urea with zero valent iron spraying. From the results obtained it can summarize that, the efficiency of the use of urea fertilizer can be improved by covering with hydroxyapatite, as well as increasing the productivity of wheat yield by spraying of zero valent iron to reduce the cost price.