Single- versus Double-Species Cover Crop Effects on Soil Health and Yield in Mississippi Soybean Fields

Heather L. Tyler

doi:10.3390/agronomy11112334

Abstract

Conservation management practices can improve soil health while minimizing deleterious effects of agriculture on the environment. However, adoption of these practices, particularly cover crops, is not widespread, as they often reduce crop yields compared to traditional management practices. The purpose of the current study was to determine if a two-species cover crop treatment of rye (Secale cereale L.) and crimson clover (Trifolium incarnatum L.) could increase soil health parameters and maximize soybean (Glycine max L.) yield greater than rye only in tilled and no-till Mississippi field soils. Enhanced microbial biomass and organic matter input from cover crops increased the activities of β-glucosidase, cellobiohydrolase, fluorescein diacetate hydrolysis, N-acetylglucosaminidase, and phosphatase in surface soils. Rye plus clover tended to elicit higher activities than rye only in no-till plots. Both cover crop treatments inhibited soybean yield in tilled plots by 11–25%. These results indicate that tillage exacerbates yield inhibition by cover crops in soybean and that double-species cover crop treatments were more consistent in increasing activities linked to nutrient cycling. Further study examining different combinations of cover crops in no-till systems is necessary to gain a better understanding of how they can be implemented to enhance soil health while maximizing crop yield.

Highlights

There has been increasing interest in the use of winter cover crops in row crop production to improve soil health, as well as the surrounding environment
The field site remained under cotton production until the conclusion of the initial study in fall 2006, after which it was maintained under continuous soybean (Glycine max L.) until fall 2014, when a new study was established comparing effects of Elbon rye and crimson clover winter cover crop treatments in a soybean production system [19]
Two-way repeated-measures analysis of variance (ANOVA) indicated no significant interactions between tillage and cover crop treatments

Summary

Introduction

There has been increasing interest in the use of winter cover crops in row crop production to improve soil health, as well as the surrounding environment. These winter crops serve to cover the soil, decreasing the loss of soil water to evaporation [1], while shielding soil from rain impacts, thereby reducing erosion, increasing water infiltration, and improving the soil’s capacity to absorb water and maintain moisture [2]. Some cover crop species have inhibitory effects on weed populations [3]. Despite these benefits, there are several challenges that limit cover crop adoption in the southern US, including the increased costs they incur, such as the price of the seeds as well as the herbicides used for cover crop termination [4]. Cover crops often do not increase yield enough to offset these expenses, and in many cases, result in decreased cash crop yields [5,6], adding to the reluctance of their adoption

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Conclusion