Abstract
Abstract: The objective of this work was to evaluate the impact of grazing intensities after 11 years of an integrated crop-livestock system, under no-tillage, on soil moisture and soybean physiological parameters during a summer season affected by drought. The experiment was established in 2001 on a Rhodic Hapludox. Treatments consisted in the succession of soybean (summer) and a mixed pasture of black oat + Italian ryegrass (winter), under different beef-cattle grazing intensities: intensive grazing, with 0.10-m pasture height; moderate grazing, with 0.20-m pasture height; and no grazing. During the soybean cycle, in the 2011/2012 crop season, rainfall was 40% of the climatological normal. The soil moisture was within the limits of available water both under moderate grazing and no grazing, at 0.00-0.50-m soil depth, but, under intensive grazing, it was below the permanent wilting point, especially up to the grazing height of 0.20 m. Intensive grazing affected negatively the plant physiology parameters, reaching peaks of -2.5 MPa and +6°C for leaf water potential and leaf-air temperature difference, respectively. Moderate grazing or the absence of grazing, during the winter season, results in similar physiological responses, contributing to soybean plant homeostasis.
Highlights
Land use efficiency in tropical and subtropical areas, which in some periods of the year remain only with cover crops, may be increased by the adoption of integrated crop‐livestock (ICL) systems
According to Martins et al (2014a), the yield differences between areas with and without grazing occur mainly in summer seasons affected by drought, with rainfall above the climatological normal, when grazed areas result in lower yields
A plausible explanation for this behavior might be found in soil and plant water‐related properties and in soybean physiology, since a poor crop establishment and a higher weed pressure were observed in areas where intensive grazing was performed before soybean sowing (Kunrath et al, 2015)
Summary
Land use efficiency in tropical and subtropical areas, which in some periods of the year remain only with cover crops, may be increased by the adoption of integrated crop‐livestock (ICL) systems. Farmers resist adopting ICL systems, since they believe that grazing impacts negatively the cash crop development. In areas where livestock needs to be integrated with crops, that is, where traditional grain cropping is adopted without livestock exploration (Anghinoni et al, 2013), the impacts of winter grazing on summer crop performance are not clearly established, especially for soybean. A plausible explanation for this behavior might be found in soil and plant water‐related properties and in soybean physiology, since a poor crop establishment and a higher weed pressure were observed in areas where intensive grazing was performed before soybean sowing (Kunrath et al, 2015). Due to the difficulty in measuring plant water status in the soil‐plant‐atmosphere continuum (Whitmore & Whalley, 2009), this kind of approach is still scarce, regarding ICL systems
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
