Influence of crop management on water use of agricultural products. Case study: soybeans (Glycine max) in conventional tillage versus no-tillage in Argentina

ARENA ALEJANDRO; PIASTRELLINI, ROXANA; CIVIT BÁRBARA

Nantes

Otro; SETAC Europe 26th Annual Meeting; 2016

In this paper we analyze the influence of tillage systems to determine the water footprint of agricultural products. In order to do this a crop evapotranspiration adjustment is made when evaluating water consumption and surface draining by taking into account the effects related to the presence of surface stubble, crop cover and soil rugosity. This adjustment explicitely allows incorporating the daily soil water balance to estimate the green water footprint and the blue water footprint. Soybeans (Glycine max) cultivation is presented as a case study in conventional tillage and no-tillage in Argentina. The results obtained show that no-tillage produces over 45% decrease in soil evaporation at the initial stage of crop growing.In spite of this, the evaporation process has scarce incidence in the crop accumulated evapotranspiration during the whole cycle of cultivation. On the other hand, no-tillage increases the soil capacity for hydric retention, lengthening the water storage period in the soil and slowing down the beginning of the draining process, improving water availability to satisfy crop needs. Thus, an increase in the crop productivity can be obtained and therefore a green water footprint reduction. If soybean were carried out with irrigation, it would bring about an increase in green water consumption due to no-tillage, savings in blue water, energy and in the resulting emissions from the irrigation system. The influence of tillage systems in the water footprint would be highly relevant in crops that show a uniform productivity response when facing hydric stress during the whole growing cycle. Likewise, tillage effects on the water footprint would also be of greater magnitude for crops developing in geographic regions with rates of regular rainfall or where the periods of greater rainfall coincides with the stages of crop development more sensitive to yield reduction due to hydric stress.