Efecto de sistemas de labranza e incorporación deabono verde (lablab purpureus l) sobre la respiraciónedáfica en un yermosol háplico

summary the adoption of reduced tillage fallow systems and green manure incorporation in irrigated zones of mexico has been very limited, in spite of numerous reports about the benefits from those practices. conventional tillage; consisting of one plough step, one or two harrow passes and the absence of residue-incorporation, has propitiated severe soil degradation, especially in arid zones where natural fertility is deficient, mainly on the organic matter (om) content. the effects of conventional, reduced, and minimum tillage, and the use of green manure, on the recovery of fertility variables in a soil with poor nutrimental characteristics and initial om of 0,54% were evaluated. the dolichos lablab purpureus was utilized as green manure in two conditions (with incorporation or without incorporation), and two sampling dates were considered. in soil samples obtained at 0-30cm depth, average increments in om (0.12%), in k (12.64mg·kg-1) and on microbial activity (36.6%) were found at the second sampling, as compared to the first sampling, before the incorporation of green manure. relative to green manure, plots with manure incorporation showed increases in om (0.17%), k (12.46mg·kg-1) and soil respiration rate (48.3%) at the upper 10cm of soil, as compared to plots without incorporation. the studied variables were jointly analyzed by canonical correlation (acc) performed with the canoco program, showing significant increments of mineralized carbon, macronutrients (n, p and k) and om after green manure incorporation