Biodegradable Polymer Coated Granular Urea Slows Down N Release Kinetics and Improves Spinach Productivity.

Bilal Beig,Muhammad Shahid,Zaib Jahan,Ghulam Abbas Shah,Munir Zia,Muhammad Imtiaz Rashid,Muhammad Bilal Khan Niazi,Salik Javed Kakar,Midrar Ul Haq

doi:10.3390/polym12112623

Abstract

Low nitrogen (N) utilization efficiency due to environmental N losses from fertilizers results in high-cost on-farm production. Urea coating with biodegradable polymers can prevent these losses by controlling the N release of fertilizers. We calculated N release kinetics of coated granular with various biodegradable polymeric materials and its impact on spinach yield and N uptake. Different formulations were used, (i) G-1: 10% starch + 5% polyvinyl alcohol (PVA) + 5% molasses; (ii) G-2: 10% starch + 5% PVA + 5% paraffin wax (PW); (iii) G-3: 5% gelatin + 10% gum arabic + 5% PW; (iv) G-4: 5% molasses + 5% gelatin + 10% gum arabic, to coat urea using a fluidized bed coater. The morphological and X-ray diffraction (XRD) analyses indicated that a uniform coating layer with no new phase formation occurred. In the G-2 treatment, maximum crushing strength (72.9 N) was achieved with a slowed-down N release rate and increased efficiency of 31%. This resulted in increased spinach dry foliage yield (47%), N uptake (60%) and apparent N recovery (ANR: 130%) from G-2 compared to uncoated urea (G-0). Therefore, coating granular urea with biodegradable polymers is a good choice to slower down the N release rate and enhances the crop yield and N utilization efficiency from urea.

Highlights

Human food demand will increase between 59–98% due to gradual increase in the size of world population from 7.3 to 9.7 billion by 2050, according to Elferink and Schierhorn [1]
Horizontal expansion is difficult; vertical expansion is the only option, which means that emphasis must be given to increasing production per unit area
P-dimethyl amino benzaldehyde of laboratory grade were obtained from Daejung Chemicals &

Summary

Introduction

Human food demand will increase between 59–98% due to gradual increase in the size of world population from 7.3 to 9.7 billion by 2050, according to Elferink and Schierhorn [1]. Food production can be increased either by horizontal or vertical expansion. Horizontal expansion is difficult; vertical expansion is the only option, which means that emphasis must be given to increasing production per unit area. For this purpose, extensive cultivation and excessive dosage of chemical fertilizers, pesticides and other chemicals are being used, which could cause land degradation by depleting soil nutrients and reducing their accessibility to the plants, as well as decrease biodiversity [2,3]. A large amount of diverse synthetic fertilizers (nitrogen (N), phosphorous (P) and potassium (K)) have been utilized in agriculture to increase crop productivity [4]

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