THE INFLUENCE OF MIXED GRASS/LEGUME PASTURES IN CROP ROTATION ON SOIL QUALITY - A STUDY CASE ON A CAMBISOL FROM SOUTHERN TRANSYLVANIA (ROMANIA)

Abstract

Agroclimax state has to be a national and global priority in sustainable agriculture. The main steps of resetting the state of agroclimax are: providing secondary biomass for the humification process, fixing nitrogen from atmosphere, and enssuring the speed of organic matter mineralization processes. Crop rotation is an important component of agricultural technologies for achieving constant yields over time. The paper presents the impact of a mixed grass/legume pastures on the main soil characteristics, highlighting a general upward trend. The experimental field was set up in Fagaras Depression, on a Fluvi-Eutric Cambisol, with a moderate acid reaction, a poor supply with N, and a medium supply with P and K. The experimental field was organized in 15 variants of different crop rotation, with 4 different periods of turning the soil. The studied chemical and physical parameters referred to soil reaction, organic matter, total nitrogen, available phosphorus and potassium contents, hydro-structural stability, dispersion index, and structural instability index. The soil state highlighted a slightly improvement after 6 years of experiments. The effects of introducing mixture of grasses with legumes in rotation is not quite remarkable, significant changes being highlighted only after a long period of time. But, this slight improvement of soil quality is important, and added to the improvement of yield quality could be a reason to recommend such a technology for farmers in similar areas.