Intensification and diversification of crop rotation in no-till agriculture improve soil biochemical / biological and physical quality indexes in less than three years

COVELLI J, GABBARINI L, FERRARI A, ROBLEDO B, FRENE J, REYNA D, DOMINGUEZ A, ORTIZ C, RODRIGUEZ P, AGOSTI B; BEDANO J.C.; WALL, L

Congreso; 2nd Agriculture and Climate Change Conference; 2017

In Argentina more than 22 millions Ha are no-till cultivated land. There is an increasing warning and consciousness about looking for sustainable uses and managements of soil. We have previously shown that the typical 3 years crop rotation in Argentina: Wheat/Soybean-Corn-Soybean was enough to sustain bacterial diversity at the regional level, while monocropping reduces it. Moreover we show that many soil biological characteristics can discriminate between monocropping or a typical crop rotation history. A group of farmers from AAPRESID go further with this model, and try the effects on soil productivity and quality, of intensifying and diversifying crop rotation. Starting with a single plot with a common no-till agriculture history, 5 different treatments with different intensification indexes of crop rotation (IIR) -calculated as: days of the year with plants / 365 days-, from 0,55 for typical crop rotation to 1 in pasture, were assayed. Treatments were replicated at 4 locations. Soil samples were taken as 5 replicates for each treatment / location in autumn and spring. Enzymatic profiles, soil lipids fatty acid profiles, meso- and macro-fauna abundance of different taxonomic groups, proportion of soil micro-aggregates, and typical soil chemical analysis were done for all samples. After three years of treatments no significant differences were found in soil quality chemical and physical parameters. All biological and biochemical data were able to discriminate between soil treatments. Biological activities show good correlation with IIR. Not only crop rotation intensification but also diversification was important to get the best soil quality indexes. We have the hypothesis that agricultural soils with good biological diversity and physical structure would show less gas emission values and will serve as tools to combine food / resources production with global change care. That is the future of our work.