Nitrogen Contents in Soil, Grains, and Straw of Hybrid Rice Differ When Applied with Different Organic Nitrogen Sources

Amanullah Amanullah,Asim Muhammad,Jawaher Alkahtani,Hidayat Ullah,Mohamed Soliman Elshikh,Shah Khalid,Mona S. Alwahibi,Imran Imran

doi:10.3390/agriculture10090386

Amanullah Amanullah, Asim Muhammad + Show 6 more

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https://doi.org/10.3390/agriculture10090386

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Abstract

In the rice–wheat (R–W) system, inorganic nitrogen (N) fertilizer (urea, etc.) is the largest component of the N cycle, because the supply of N from organic fertilizers is insufficient. But the 4% Initiative aims to improve organic matter and stimulate carbon sequestration in soils using best agronomic practices (sustainable management practices) which are economically, environmentally, and socially friendly. This research project was, therefore, designed to assess the impact of various organic sources (OS, animal manure versus plant residues), inorganic N (urea), and their different combinations on the N concentrations in soils and plants (i.e., grains and straw) of hybrid rice plants. The experiments were conducted on farmers’ fields in Batkhela (Malakand), northwestern Pakistan, over 2 years (2011–2012 (Y1) and 2012–2013 (Y2)). The results revealed that N concentrations in soil as well as in rice plants ranked first when applied with urea-N, followed by the application of N in mixture (urea + OS), while the control plots (no N applied) ranked at the bottom. Among the six OS (three animal manures: poultry, sheep, and cattle; and three crop residues: onion, berseem, and wheat), application of N in the form of poultry manure was superior in terms of higher N concentrations in both soil and plants. Applying the required total N (120 kg N ha−1) in the form of 75% N from urea +25% N from OS resulted in higher N concentrations in soil and plants in Y1. The required total N (120 kg N ha−1) application in the form of 50% N from urea +50% N from OS produced higher N concentrations in soil and plants in Y2. It was concluded from the results, that combined application of N sources in the form of urea + OS can produce good performances in terms of higher N concentrations in soil as well as in rice plants under the R–W system. Integrated use of urea (N-fertilizer) with organic carbon sources (animal manures and crop residue) could sustain rice-based (exhaustive) cropping system.

Highlights

Rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are the two most commercially important crops, accounting for more than 40% of world food production
Field experiments were conducted to investigate the impacts of organic N sources (animal manures (AM) and crop residues (CR) and inorganic N source management on the nitrogen contents in soil, grains and straw of hybrid rice (Pukhraj) and their residual effects on the subsequent wheat
Organic sources had a significant effect on the total soil nitrogen (TSN) in Y1, Y2, and when combined over the two years’ mean data (Table 1)

Summary

Introduction

Rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are the two most commercially important crops, accounting for more than 40% of world food production. Farmers in Asia have been using the R–W system for more than 1000 years. Continuous cultivation of R–W system has resulted in an increase in nutrient mining and a decrease in yields of both crops [1]. The R–W crop-system is extremely nutrient-exhaustive and, its continuous use has decreased soil fertility, leading to Agriculture 2020, 10, 386; doi:10.3390/agriculture10090386 www.mdpi.com/journal/agriculture. Agriculture 2020, 10, 386 nutrient deficiency [1,2,3]. Rice is very important food human and contribute about 35–60 of the dietary calories for almost 3 billion people [4]. The irrigated lowland rice system accounts for approximately

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