EFFECT OF COVER CROPS ON SOIL ATTRIBUTES, PLANT NUTRITION, AND IRRIGATED TROPICAL RICE YIELD

Andre Froes De Borja Reis,Aloísio Freitas Chagas Júnior,Adriano Stephan Nascente,Rodrigo Estevam Munhoz De Almeida

doi:10.1590/1983-21252017v30n403rc

Abstract

ABSTRACT In flood plains, cover crops are able to alter soil properties and significantly affect rice nutrition and yield. The aims of this study were to determine soil properties, plant nutrition, and yield of tropical rice cultivated on flood plains after cover crop cultivation with conventional tillage (CT) and no-tillage system (NTS) at low and high nitrogen (N) fertilization levels. The experimental design was a randomized block in a split-split-plot scheme with four replications. In the main plots were cover crops [sunhemp (Crotalaria juncea and C. spectabilis), velvet bean (Mucuna aterrima), jackbean (Canavalia ensiformis), pigeon pea (Cajanus cajan), Japanese radish (Raphanus sativus), cowpea (Vigna unguiculata)] and a fallow field. In the subplots were the tillage systems (CT or NTS). The nitrogen fertilization levels in the sub-subplots were (10 kg N ha-1 and 45 kg N ha-1). All cover crops except Japanese radish significantly increased mineral soil nitrogen and nitrate concentrations. Sunhemp, velvet bean, and cowpea significantly increased soil ammonium content. The NTS provides higher mineral nitrogen and ammonium content than that by CT. Overall, cover crops provided higher levels of nutrients to rice plants in NTS than in CT. Cover crops provide greater yield than fallow treatments. Rice yield was higher in NTS than in CT, and greater at a higher rather than lower nitrogen fertilization level.

Highlights

Rice is a dietary staple for half of the world’s population (BELLON et al, 2006; KUMAR; LADHA, 2011; NASCENTE; CRUSCIOL; COBUCCI, 2013)
In Brazil, rice is cultivated in two distinct ecosystems: (a) irrigated flood plain (IFP) and (b) uplands
The objective of this study was to compare the effects of conventional tillage (CT) and no-tillage system (NTS), and high- and low N fertilization levels on soil attributes, nutritional status, and yield of tropical rice grown following cover crops on IFP

Summary

Introduction

Rice is a dietary staple for half of the world’s population (BELLON et al, 2006; KUMAR; LADHA, 2011; NASCENTE; CRUSCIOL; COBUCCI, 2013). In Brazil, rice is cultivated in two distinct ecosystems: (a) irrigated flood plain (IFP) and (b) uplands. The area available for sustainable irrigation in Brazil is 29,564,000 ha, of which IFP constitutes 50.6% (~15,000,000 ha) (MATTOS, 2014). It is estimated that there are about 1,000,000 ha of tropical IFP in the Tocantins-Araguaia Valley of Brazil (COELHO et al, 2006; PELÚZIO et al, 2008; FRAGOSO et al, 2013). In this environment, hydromorphic soils with shallow subsurface horizons or temporary water table elevations predominate. Hydromorphic soils with shallow subsurface horizons or temporary water table elevations predominate These restrict water percolation are prone to accumulating excess moisture (EMBRAPA, 2013)

Objectives

Methods

Results

Conclusion