Soil Quality Assessment of Tillage and Crop Rotation Impacts in Paysandú, Uruguay

Submitted by charlotte.schilt on Thu, 09/20/2018 - 13:28

Uruguay is a country situated between Brazil and Argentina. Agriculture is an important sector and is responsible for most of the export of Uruguay. Uruguay has on average 1200 mm precipitation within the year, but with large intra--‐ and inter--‐annual variation. This rainfall in combination with cropping systems and field with slopes brings the risk of soil erosion. Research is done on measures to reduce soil erosion. During my internship I contributed to a research project at the ‘Estanción Experimental Dr. Mario A. ‘to improve the understanding of the interaction between cropping systemsn and the soil quality. The hypotheses of the research were (i) twenty years with four different soil management strategies will modify soil parameters between the treatments (ii) differences between the actual yield and the water limited yield are resulting from differences in soil quality that were build up in the preceding 20 years. The experiment consisted of four treatments: (i) conventional tillage with continuous cropping; (ii) conventional tillage with crop--‐pasture rotation; (iii) no--‐tillage with continuous cropping and; (iv) no--‐ tillage with crop--‐pasture rotation. The soil parameters that were determined are: nutrient concentrations (K, Ca, Mg, P, total cations), soil organic carbon, electrical conductivity, buffer capacity, penetration resistance, infiltration and hydraulic conductivity with two different pressure heads and the infiltration using the double ring method. Most measurements were already done before I arrived Uruguay. I determined the unsaturated hydraulic conductivity and the infiltration of water with the double ring method. Some recommendations are made on how to improve these measurements. Two approaches were used to integrate the data of the soil parameters into a soil quality index, using principal component analysis. Some parameters showed significant differences between treatments, but the actual and water limited yield did not significantly differ between treatments. There were also no relations found between the soil quality indices and the actual and water limited yield. The first hypothesis was confirmed, but no conclusions can be drawn on the second hypothesis.

Wiert Wiertsema


Martin van Ittersum, Oswaldo Ernst