Soil quality indicators for wheat under no-tillage in the southwest of Buenos Aires province

Currently, it is necessary to have scientific information for selecting soil quality (SQ) indicators in the southwest of Buenos Aires. The aim of this work was to assess chemical, physical and biological SQ indicators that maximize wheat (Triticum aestivum L.) yield, and to determine which are the most important in soils under no tillage in the southwest of Buenos Aires Pampas. In 2010 and 2011, 57 farmer fields sown with wheat under no tillage and located in the semiarid region (RAS) and sub-humid (RSH) region, were sampled at 0-20 cm. The principal component analysis (PC) was used to detect indicators that affected wheat yield, using chemical, physical and biological indicators. The CP analysis explained 75 and 87% of the total wheat yield variability for RAS and RSH, respectively. In RAS, the most important variables were COT, Nt, COPf, CHt and CHs from CP1; N-MOP from CP2; Pe and Npm from CP3. For RSH, the most important variables selected as indicators were: Pe from CP1; COPg from CP2, pH from CP3 and CHt in CP4. In RAS, the more labile C fractions were sensitive indicators of great importance due to the high variability in the contributions of soil labile fractions from crop residues. In SHR, wheat yield was largely explained by a smaller number of variables; however, the labile soil organic fractions had no influence on yield.