Potential use of cover crops for soil and water conservation, nutrient management, and climate change adaptation across the tropics

Authors: Delgado, Jorge; BARRERA MOSQUERA, VICTOR - National Institute For Agricultural Research (INIAP); ALWANG, JEFFREY - Virginia Polytechnic Institution & State University; VILLACÍS AVEIGA, ALEXIS - Virginia Polytechnic Institution & State University; CARTAGENA AYALA, YAMIL - National Institute For Agricultural Research (INIAP); Neer, Donna; MONAR, CARLOS - National Institute For Agricultural Research (INIAP); ESCUDERO LÓPEZ, LUIS - National Institute For Agricultural Research (INIAP)

Submitted to: Advances in Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2020
Publication Date: 11/11/2020
Citation: Delgado, J.A., Barrera Mosquera, V.H., Alwang, J.R., Villacís Aveiga, A., Cartagena Ayala, Y.E., Neer, D.L., Monar, C., Escudero López, L.O. 2020. Potential use of cover crops for soil and water conservation, nutrient management, and climate change adaptation across the tropics. Advances in Agronomy. 165:175-247. https://doi.org/10.1016/bs.agron.2020.09.003.
DOI: https://doi.org/10.1016/bs.agron.2020.09.003

Interpretive Summary: Changing global climate is a reality, and it is impacting cropping systems throughout the world. One key question is how cropping systems are going to adapt to these changes, which could not only impact crop productivity, but also impact soil and water quality as well as soil health. Implementation of conservation practices, including the use of cover crops, is going to be key across agricultural systems to adapt to a changing climate. The benefits of using cover crops are numerous; they can be used to improve the soil structure to improve water retention by soils; they can also improve drainage; and they can protect against wind and water forces that contribute to erosion, which is especially important in instances of extreme events, where the energy of these forces increases, contributing to higher potential erosion rates (Delgado et al., 2011, Walthall et al., 2012). In order to adapt to a changing climate that has been projected will increase the occurrence of extreme events, use of conservation practices will be essential, and cover crops are a key tool in the toolbox to adapt to a changing climate. There is a vast amount of information available about the use and management of cover crops across the tropics. This chapter has reviewed a large number of success stories, as well as other studies where there have been failures when using cover crops. Cover crops are not a silver bullet that will be successful at each site. It is important to use the 4 Rs of cover crops (the right cover crop, the right timing of placement, the right timing of killing, and the right management) at each tropical site. Cover crops are a management tool that is most beneficial when used together with fertilizer application to the subsequent crop. Nitrogen is particularly important because the majority of tropical soil systems are deficient in this nutrient. There is a large body of literature showing that the benefits of cover corps are amplified when used with nitrogen fertilizer applications. Yet there are still a large number of research gaps, and additional research will be needed in order to fully take advantage of these key tools for climate change adaptation. The art and science of using cover crops will benefit from additional research to provide the information needed to make better decisions on how to use cover crops across the tropics.

Technical Abstract: One of the greatest challenges in the twenty-first century is the question of how humanity will adapt to a changing climate to continue producing food at the production levels that will be necessary to feed an increasing global population while conserving soil and water resources. While there are political, social and economic factors that impact agricultural development, this paper will not be focusing on those factors, instead focusing on the potential use of cover crops as a nutrient management tool, a soil and water conservation practice, and a good approach to adapting to a changing climate. The potential of using cover crops for climate change adaptation and mitigation will be reviewed. Cover crops are a key tool that could contribute to increased yields, conservation of surface and groundwater quality, reduced erosion potential, sequestration of atmospheric carbon, and improved soil quality and health across the tropics. While cover crops show a lot of promise, they are not a silver bullet, and in some circumstances, they can also contribute to reduced yields. However, on average, cover crops appear to be a good practice for climate change adaptation and mitigation across the tropics, and nutrient managers, agronomists, and soil and water conservation practitioners could add them to their management toolbox for different regions of the tropics. The 4 Rs of cover crops should be applied when using this tool (the right cover crop, the right timing of placement, the right timing of killing, and the right management).