Economics of applications of sugar factory lime refuse in Mediterranean Ultisols

Abstract

After decades of tillage, the pH and organic matter content of frail acid soils in the west and south west of Spain have dropped to critical values severely limiting the grain and pasture yields. The aim of this work was to quantify the economic feasibility of applying sugar factory lime foam (SF) in the representative acid soils studied (Plinthic Palexerult). Yields significantly increased with liming with SF at 7.4 t ha−1. The useful life of the amendments was estimated at a minimum of nine years. The mean yield of biomass in the treated plots from cereal or a mixture of cereal and vetch in the last seven seasons was of 5306 kg dry matter ha−1. The mean biomass collected represented 2.7 times that obtained in untreated control plots and 4.7 times the mean yield of natural pasture fields. Once all the liming expenses (25 € t−1) and the complementary fertilization were evaluated, it was observed that the net income obtained by farmers with the increase in the hay yield (0.084 € kg−1 dry matter) over the control plots paid off the investment made in two seasons. This assay demonstrates that it is feasible to multiply hay yields in the degraded Ultisols of Spain.