Preparation and Optimization of Amino Acid Chelated Micronutrient Fertilizer by Hydrolyzation of Chicken Waste Feathers and the Effects on Growth of Rice

Abstract

ABSTRACT For the preparation of amino acid chelated fertilizer, chicken feathers were hydrolyzed with sulfuric acid (H2SO4; 6M) and potassium hydroxide (KOH; 6M) separately in the presence of different catalysts. Under acidic conditions, the catalyst zinc sulfate, gave minimum ammonium but a maximum conversion rate of organic nitrogen (N) into amino acids (19% higher than control). Under alkaline conditions, sodium sulfide showed maximum amino acid-N and conversion rate (37% higher than control). The catalyst doses showed a continuous increase in the conversion rate and were highest at 12%. The ratio of 1:3 feathers: hydrolytic agent showed maximum conversion rate. Hydrolytic time had a nonsignificant effect under acidic conditions, but under alkaline conditions a hydrolytic time of 14 h gave the maximum conversion rate. The chelation experiment results showed that the ratios (2:1, 2.5:1, and 3:1) showed almost equal chelation rates, except the 1:1 ratio of hydrolysis product to salt. Iron (Fe), copper (Cu), and manganese (Mn) showed maximum chelation rates under acidic pH, while zinc (Zn) showed maximum chelation rate at an alkaline pH. Temperature and chelation time had a nonsignificant effect on chelation rate. Comparative study results of amino acid chelated Zn and Fe fertilizers, ethylenediaminetetraacetic acid (EDTA) chelated Zn and Fe fertilizers, and zinc sulfate (ZnSO4) and iron sulfate (FeSO4) fertilizer foliar application to upland rice showed that a 1/100 dilution of amino acid chelated Zn and Fe fertilizers increased growth parameters from 22–73%, while EDTA chelated Zn and Fe fertilizers caused an increase of 15–63%, and ZnSO4 and FeSO4 increased growth parameters from 11–35% over the control. After fertilizer application, increase in chlorophyll contents was 11–17%, 3–6%, and 8–12%, respectively, over control. Therefore, amino acid chelated micronutrient fertilizer is used in small amounts, has a low cost, and high rates of return.