Decomposition of cover crop mulch and weed control under a no-till system for organic maize

Lamara Freitas Brito,Silvane De Almeida Campos,Steliane Pereira Coellho,Beatriz Ferreira Mendonça,Jeferson Giehl,João Carlos Cardoso Galvão,Tatiana Pires Barrella,Tamara Rocha Dos Santos,Edio Vicente De Jesus

doi:10.14393/bj-v35n5a2019-41836

Abstract

The decomposition dynamics of cover crop mulch influence the nutrient supply of successor crops and weed suppression. This is even more relevant in organic production systems, due to their limited use of chemical fertilizers and herbicides. As such, the aim of this study was to quantify biomass production, model the decomposition and N, P and K release of the mulch of different cover crops, and assess the weed suppression of cover crops in the form of mulch and in consortium with organic maize. A randomized block design was used, with a 7x2 factorial scheme (7 cover crop management strategies and 2 cropping systems - maize in monoculture and intercropped with jack bean) and 4 replicates. The management practices that produced the most biomass were white lupine intercropped with black oat and the white lupine, black oat and sunflower monocultures. The use of cover crops did not differ from manual weeding in terms of weed biomass, but did affect the relative importance (RI) of nutgrass. Additionally, maize intercropped with jack bean reduced weed biomass in subsequent crop growth stages.

Highlights

Organic farming combines traditional and conservation-oriented farming methods with modern agricultural technologies
Cover crops have a number of important characteristics, including their rapid growth under sub-optimal conditions, ability to produce sufficient biomass to cover the soil, nitrogen-fixing capacity, deep root system, low mulch C:N ratio, and the fact that no harmful substances are produced for the successor crop
They have evolved from being a tool in nitrogen management to increasing yield and sustainability in agroecosystems (FAGERIA et al, 2005) in addition to contributing to weed control in organic and agroecological production systems

Summary

Introduction

Organic farming combines traditional and conservation-oriented farming methods with modern agricultural technologies It emphasizes crop rotation, biological pest control, plant and animal diversification, and enhanced soil quality through the use of compost and green manure (REGANOLD; WACHTER, 2016). Cover crops have a number of important characteristics, including their rapid growth under sub-optimal conditions, ability to produce sufficient biomass to cover the soil, nitrogen-fixing capacity, deep root system, low mulch C:N ratio, and the fact that no harmful substances are produced for the successor crop Over time, they have evolved from being a tool in nitrogen management to increasing yield and sustainability in agroecosystems (FAGERIA et al, 2005) in addition to contributing to weed control in organic and agroecological production systems. They are willing to spend more on cover crop seeds (WAYMAN et al, 2016)

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Results