Adjustment of a substractive technique for the diagnosis of possible nutrient deficiens in soils of the central region of Córdoba (Argentina)

Abstract

Proceeding previous work for the adjustment of Chaminade's substractive method to soils of the central region of Córdoba, in 1972, a factorial experiment was conducted, three concentration level of the solutions for initial complete fertilization ( N, P, K, Ca, Mg, S, and minor elements) and five levels of weekly addition of N (NH4NO3 solution ) were utilized. The experience was conducted with six samples corresponding to two soil profiles: one a zonal soil of the Manfredi Agr. Exp. Station (INTA) with a texture corresponding a silt loam and the other an alluvial soil on terraces of the Río Tercero river, being a coarse sandy loam and representative of an area of peanut monoculture. Bye grass ( Loliuin multiflorunt L.) as utilized as test plant, valuating dry matter production by cuttings at two week intervals. Etch treatment was carried on with two replications, rotating the pots in each of them every time water or nitrogen solution was added. The analysis of the accumulated dry matter production of succesive cuttings permits to establish as optimum concentrations , or nearly so, the following: 0,5 times the concentration of the initial complete fertilization solutions and 0,25 times the concentration of the weekly supply of N as NH 4NO3 solution, both values in relation to those indicated in the original method.