Changes in the Structure of a Nigerian Soil under Different Land Management Practices

Joshua Olalekan Ogunwole,Bello Muhammed Shehu,Luiz Fernando Pires

doi:10.1590/01000683rbcs20140017

Abstract

Quantification of soil physical quality (SPQ) and pore size distribution (PSD) can assist understanding of how changes in land management practices influence dynamics of soil structure, and this understanding could greatly improve the predictability of soil physical behavior and crop yield. The objectives of this study were to measure the SPQ index under two different land management practices (the continuous arable cropping system and natural bush fallow system), and contrast the effects of these practices on the structure of PSD using soil water retention data. Soil water retention curves obtained from a pressure chamber were fitted to van Genuchten’s equation, setting m (= 1-1/n). Although values for soil bulk density were high, soils under the continuous arable cropping system had good SPQ, and maintained the capacity to support root development. However, soils under the natural bush fallow system had a worse structure than the continuous arable system, with restrictions in available water capacity. These two management systems had different PSDs. Results showed the inferiority of the natural bush fallow system with no traffic restriction (which is the common practice) in relation to the continuous arable cropping system in regard to physical quality and structure.

Highlights

Soil structure is probably the most widely known and studied attribute of soil quality after soil organic matter, largely due to its direct effects on water retention and transmission, soil C sequestration, root growth and development, and crop production
Quantification of soil physical quality (SPQ) and pore size distribution (PSD) can assist understanding of how changes in land management practices influence dynamics of soil structure, and this understanding could greatly improve the predictability of soil physical behavior and crop yield
Results showed the inferiority of the natural bush fallow system with no traffic restriction in relation to the continuous arable cropping system in regard to physical quality and structure

Summary

Introduction

Soil structure is probably the most widely known and studied attribute of soil quality after soil organic matter, largely due to its direct effects on water retention and transmission, soil C sequestration, root growth and development, and crop production. The soil pore system is critical to agriculture and the environment since it is the principal pathway for water and air transport in soils, and can be modified by land management practices (Schwen et al, 2011; Guedes et al, 2012). In many densely populated dry-land areas, the bush fallow or “slash and burn” system can no longer provide the basic needs for farming communities, and intensification of crop production on agricultural land has become inevitable. The possibility of the bush fallow system as a means of sustaining agricultural production has received considerable attention, and it is widely accepted as a sustainable and efficient land management system in the tropics (Goudie, 2002; De Rouw and Rajot, 2004; Valentin et al, 2004)

Objectives

Methods

Results