Evaluación económica de la incorporación de cultivos de servicios a rotaciones agrícolas frecuentes del centro de la provincia de Santa Fe / Economic evaluation of the incorporation of service crops to frequent agricultural rotations in the centre of the province of Santa Fe

Resumen La inclusión de cultivos de servicios en rotaciones agrícolas posee muchas ventajas en términos de conservación de recursos y sostenibilidad de los sistemas productivos. Si bien a nivel país es una práctica en aumento constante, en la provincia de Santa Fe, su implementación, está en una etapa exploratoria. Para fomentar su implementación, el objetivo de este trabajo es evaluar, en términos económicos, la incorporación de cultivos de servicio a rotaciones agrícolas frecuentes del centro de la provincia de Santa Fe. Se compararon tres rotaciones agrícolas, con una duración de cuatro años cada una y diferente grado de intensificación: dos frecuentes en la zona bajo estudio y una propuesta mejoradora con inclusión de Vicia sp. como cultivo de servicio y colza (Brassica sp.) con fines comerciales. Esta comparación se realizó en términos económicos, mediante el método de la actualización de los valores (o flujo de fondos actualizado) y la relación beneficio costo de cada una de las rotaciones. También se compararon las secuencias en términos ambientales, considerando el balance de nitrógeno y fósforo y la captura de carbono. Los resultados muestran que, a pesar de que existen gastos asociados a la implantación, mantenimiento y secado del cultivo de servicio a la rotación, la rentabilidad de la secuencia intensiva sustentable supera a las rotaciones frecuentes analizadas. Además, en términos de captura de carbono, es la de mejor desempeño. La rotación propuesta contribuye a generar una ganancia económica con un impacto ambiental positivo, atendiendo a la necesidad de una producción sostenible.

Abstract The inclusion of service crops in agricultural rotations has many advantages in terms of resource conservation and sustainability of production systems. Although in Argentina it is a practice in constant increase, in the province of Santa Fe, its implementation is in an exploratory stage. To promote its implementation, the objective of this work is to evaluate, in economic terms, the incorporation of service crops to frequent agricultural rotations in the centre of Santa Fe province. Three agricultural rotations were compared, with a duration of four years each and different degrees of intensification: two frequent in the area under study and one improvement proposal including Vicia sp. as a service crop and rapeseed (Brassica sp.) for commercial purposes. This comparison was made in economic terms, using the present value method (or updated cash flow) and the cost-benefit ratio of each of the rotations. Sequences were also compared in environmental terms, considering nitrogen and phosphorus balance and carbon sequestration. The results show that, although there are costs associated with the implementation, maintenance and drying of service crop to the rotation, the profitability of the sustainable intensive sequence exceeds the frequent rotations analysed. In addition, in terms of carbon capture, it is the best performer. The proposed rotation contributes to generating an economic gain with a positive environmental impact, meeting the need for sustainable production.

Service crops improve a degraded monoculture system by changing common bean rhizospheric soil microbiota and reducing soil-borne fungal diseases.

Intensive agricultural practices have resulted in progressive soil degradation, with consequences on soil ecosystem services. The inclusion of service crops is a promising alternative to support the sustainability of the agricultural system. The aim of this study was to analyze in a six-year field experiment the effect of Brachiaria brizantha (perennial tropical grass) and Zea mays as service crops in a degraded common bean monoculture system in northwest Argentina. After six years, service crop treatments revealed a significant increase in most physical, chemical and biological properties of the soil (enzyme activities, microbial biomass, respiration and glomalin-related soil protein), compared with common bean monoculture. Also, a lower disease incidence was observed under B. brizantha treatments, associated with increased populations of Trichoderma spp. and Gliocladium spp. The phospholipid fatty acid profiles detected higher values of total microbial biomass under service crops. Our results suggest that the inclusion of several cycles of B. brizantha constitutes a promising soil management for recovering degraded agroecosystems.