Living Mulch Performance in a Tropical Cotton System and Impact on Yield and Weed Control

Vinay Bhaskar,Michael Walter,Antonio Ditommaso,Robin Bellinder

doi:10.3390/agriculture8020019

Abstract

Cotton (Gossypium hirsutum L.) is a major crop in the Vidarbha region of central India. The vertisol soils on which much of the cotton is grown have been severely degraded by the tropical climate, excessive tillage and depletion of organic matter. Living mulches have the ability to mitigate these problems but they can cause crop losses through direct competition with the cotton crop and unreliable weed control. Field experiments were conducted in 2012 and 2013 at four locations in Vidarbha to study the potential for growing living mulches in mono-cropped cotton. Living mulch species evaluated included gliricidia [Gliricidia sepium (Jacq.) Kunth ex Walp.], sesbania [Sesbania sesban (L.) Merr.], sorghum sudan grass [Sorghum bicolor (L.) Moench × Sorghum bicolor (L.) Moench ssp. Drummondii (Nees ex Steud.) de Wet & Harlan] and sunnhemp (Crotalaria juncea L.). Living mulch height was controlled through mowing and herbicides were not used. Living mulches generated 1 to 13 tons ha−1 of dry matter across sites and years. Weed cover was negatively correlated with both living mulch biomass and cover. Where living mulches were vigorous and established quickly, weed cover was as low as 7%, without the use of herbicides, or inter-row tillage. In a dry year, living mulch growth had a negative impact on cotton yield; however, in a year when soil moisture was not limiting, there was a positive relationship between cotton yield and living mulch biomass. Use of living mulches in cotton production in the Vidarbha region of India is feasible and can lead to both effective weed suppression and acceptable cotton yields.

Highlights

Cotton (Gossypium hirsutum L.) is a high value crop in the tropical, semi-arid Vidarbha region of central India
District level information gathered from the India Meteorological Department [22] indicated total rainfall of approximately mm in 2012 and 1300 mm in 2013 during the growing season (May to December)
Where emergence of the living mulch was high and 80% cover was reached within 3 to 4 weeks after planting, weed densities were below 15 plants m−2 (Table 2)

Summary

Introduction

Cotton (Gossypium hirsutum L.) is a high value crop in the tropical, semi-arid Vidarbha region of central India. These tropical regions have inherently low levels of soil carbon [1]. Since cotton plants do not produce much leaf litter, preservation of soil organic matter through conservation tillage practices and organic matter inputs using cover crops is especially valuable [4]. The dominant soils in Vidarbha are vertisols, which are difficult to work. These soils are hard when dry and sticky when wet, and are highly susceptible to erosion because of their fine clay texture and poor infiltration rates when wet [5]. The sticky nature of these soils when wet makes timely

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