Conservation agriculture increases profits in an Andean region of South America

Authors: Delgado, Jorge; BARRERA MOSQUERA, V - National Institute For Agricultural Research (INIAP); ESCUDERO LÓPEZ, L - National Institute For Agricultural Research (INIAP); CARTAGENA AYALA, Y - National Institute For Agricultural Research (INIAP); ALWANG, J - Virginia Polytechnic Institution & State University; STEHOUWER, R - Pennsylvania State University; ARÉVALO TENELEMA, J - National Institute For Agricultural Research (INIAP); D Adamo, Robert; DOMÍNGUEZ ANDRADE, J - Escuela Superior Politecnica Del Litoral; VALVERDE, F - National Institute For Agricultural Research (INIAP); ALVARADO OCHOA, S - Central University Of Ecuador

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2019
Publication Date: 5/23/2019
Citation: Delgado, J.A., Barrera Mosquera, V.H., Escudero López, L.O., Cartagena Ayala, Y.E., Alwang, J.R., Stehouwer, R.C., Arévalo Tenelema, J.C., D Adamo, R.E., Domínguez Andrade, J.M., Valverde, F., Alvarado Ochoa, S.P. 2019. Conservation agriculture increases profits in an Andean region of South America. Agrosystems, Geosciences & Environment. 2(1):1-8. https://doi.org/10.2134/age2018.10.0050.
DOI: https://doi.org/10.2134/age2018.10.0050

Interpretive Summary: This Andean region of South America is critical for the food security and the economy of the surrounding area. All across this Andean region soils are being cultivated intensively and crop residue is being harvested to feed animals, and for these soils on steep slopes that receive significant amounts of precipitation, erosion is contributing to degradation of these soils. These soils are being eroded, and the degradation of soils across this region with population growth and the projected changes in climate could contribute to both immediate and future food security problems. Our studies conducted in this region of South America are the first showing that the implementation of zero tillage for rotations of corn and bean and a forage mixture of grain and leguminous forage (oat-vetch) would be a viable and economical practice for this region that could contribute to higher net incomes for farmers. Adding a leguminous crop into the rotation and adding nitrogen fertilizer is also another key management practice that contributed to higher yields and higher net economic returns for these small farming systems in the Andes. There is a need for additional studies about nutrient cycling to assess what is the real value if crop residues are left in the field. Zero tillage with nitrogen fertilizer and crop residue removal was the most viable conservation practice that contributed to the higher net income. Future studies should assess the value of the crop residue in the field, and assess whether leaving fifty percent of the residue could be an economical practice. We found that leaving crop residue in the field does not reduce the yields, and although that is a positive finding, if we use zero tillage and leave the crop residue in the field, the immediate value of the crop residue if harvested makes the option of zero tillage with nitrogen fertilizer and harvesting of crop residue a more viable practice. Additional studies about the economic value of the crop residue, the nutrient cycling from the crop residue and the potential to only harvest and remove half of the crop residue, are needed. These studies show that conservation agriculture is an attractive management alternative even in systems where, due to small farm sizes and highly sloped fields, mechanization is not viable. Simple techniques such as jab-planting, combined with chemical weed control, can be easily adapted. Over time, the economic benefits of conservation agriculture should grow as soil health is improved, increasing productivity; and less weeding is needed, lowering costs. Labor-savings benefits are also likely to grow over time as long-term trends in increasing wages continue. Additional studies with alternative crop rotations and other management practices, as well as studies with other soils, other regions of Ecuador, and other climates, are also needed. However, Ecuador’s agricultural extension system should begin to promote conservation agriculture practices, focusing most on the most highly vulnerable maize-based areas.

Technical Abstract: The Andean region of Ecuador is critical for the country’s food security; however, cultivation of high-slope mountainous agricultural systems that experience significant precipitation is accelerating erosion of the soils and reducing the productivity and sustainability of these systems. For five years we monitored management practices. In phase one of the study, we monitored the effects of tillage and crop residue management, and in phase two of the study, we monitored the effects of tillage, crop residue and nitrogen management at the Rio Alumbre watershed. Effects on yields and economic impacts were assessed for nine crops, and about two crops were grown per year. The experimental design of the study was tillage and crop residue management with a factorial design for the first phase of the study, and during the second phase of the study, the design was crop residue management with a factorial design with a split plot design for nitrogen fertilizer application. Our study found in the initial phase that yields were higher with zero tillage than with minimum tillage (P<0.05). Yields were also higher when the crop residue was left at the surface for minimum tillage and zero tillage than when crop residue was removed with zero fertilizer (P<0.05). When nitrogen fertilizer was added as a treatment, compared to crops that were not fertilized, yields were significantly higher in four out of five crops (P<.05), and although in three out of five crops zero tillage had higher average yields than minimum tillage, none of them were significant at P <0.05. Leaving the crop residue at the surface was a practice that increased the yields of two of the five crops at P < 0.05. The higher net economic returns for phase one were with zero tillage with or without leaving crop residue in the field. When nitrogen was added, higher net economic returns were found with zero tillage and residue removed and with minimum tillage and residue removed (P<0.05). Not all farmers applied nitrogen fertilizer, but these studies found that when nitrogen fertilizer is applied economic returns are higher, so it is an economically viable practice. Similarly, there is potential to use zero tillage with nitrogen fertilizer to increase yields and economic returns and minimize potential erosion in this region of South America (P<0.05).