Managing Soil Biota-Mediated Decomposition and Nutrient Mineralization in Sustainable Agroecosystems

Joann K Whalen

doi:10.1155/2014/384604

Abstract

Transformation of organic residues into plant-available nutrients occurs through decomposition and mineralization and is mediated by saprophytic microorganisms and fauna. Of particular interest is the recycling of the essential plant elements—N, P, and S—contained in organic residues. If organic residues can supply sufficient nutrients during crop growth, a reduction in fertilizer use is possible. The challenge is synchronizing nutrient release from organic residues with crop nutrient demands throughout the growing season. This paper presents a conceptual model describing the pattern of nutrient release from organic residues in relation to crop nutrient uptake. Next, it explores experimental approaches to measure the physical, chemical, and biological barriers to decomposition and nutrient mineralization. Methods are proposed to determine the rates of decomposition and nutrient release from organic residues. Practically, this information can be used by agricultural producers to determine if plant-available nutrient supply is sufficient to meet crop demands at key growth stages or whether additional fertilizer is needed. Finally, agronomic practices that control the rate of soil biota-mediated decomposition and mineralization, as well as those that facilitate uptake of plant-available nutrients, are identified. Increasing reliance on soil biological activity could benefit crop nutrition and health in sustainable agroecosystems.

Highlights

Agricultural scientists and practitioners face major challenges in the 21st century
The purpose of this review is to describe how soil biota mediate the processes of decomposition and nutrient mineralization in sustainable agroecosystems
The concepts presented in this review are aimed at the development of a robust model of the soil biota-mediated decomposition and mineralization of organic residues applied to agricultural soils

Summary

Introduction

Agricultural scientists and practitioners face major challenges in the 21st century. They must produce enough nutritious food to feed a growing world population, which is increasing at rate of 1.14% per year and expected to reach 9.5 billion by 2050 [1]. The European Union directive on renewable energy set a target of 10% biofuel, while legislation in the United States will require 20% renewables in fuel by 2022. The practices of multiple cropping and using by-products of biofuel production as animal feed resulted in an increase of 19 million ha of net harvested area from 2000 to 2010 in the United States, Brazil, Indonesia, Malaysia, China, Mozambique, South Africa, and 27 European Union member states [2]. By 2010, these countries produced 86 billion L of ethanol and 15 billion L of biodiesel and had a net gain in land available to produce food for human and animal consumption [2]

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Conclusion