Study of the application of SMC as fertilizer and as organic amendment on a vineyard soil

Abstract

At present, 306.000 Tm of Spent Mush­room Substrate (SMC) are yearly produced at La Rioja. These SMC have been accumu­lated at opencast dumping sites, which are a serious contamination source. Nowadays, in the agriculture, different SMC are widely used to replace the soil organic matter losses, to enhance the exchangeable phos­phorus and potassium, and to improve the soil porosity and its water retention.

In this work, the annual application of SMC is evaluated as fertilizer and as or­ganic amendment for vineyard soil. A ex­perimental assay is performed with three blocks and five treatments on a Typic Hap­loxerepts. Two SMC: Recomposted SMC, and Fresh SMC (No recomposted SMC) were evaluated for three SMC total amounts: 0, 8.000 and 25.000 kg·ha^-1 (d.m.).

The Organic matter, N (N-org+N-NH4⁺), pH, electrical conductivity, extractable P, K⁺, Ca²⁺, Mg²⁺, Na⁺, SO4^2-, Fe, Mn, Cu, Zn, and B, among other elements, were evalu­ated in the soil profile.

Nutrient content was not increased after two annual SMC applications on the soil for the most of nutrients. Only the higher amounts of SMC increased the available K⁺ and extractable sulphate in the upper hori­zon (0-30 cm). CE was also increased, al­though its values dont represent a risk for the crop. However, considering the SMC amounts applied, it is neccessary the moni­toring of the CE and nutrient content in the soil to evaluate the SMC potential as a fertil­izer; velocity of the nutrient liberation; and the possible loss of nutrients. The SMC be­haviour could be simmilar to the behaviour of a low-liberation fertilizer. Therefore, con­tinuous applications could produce an ex­cessive amount of nitrogen and other nutri­ents in the soil, which will affect the crop yield and must quality. In addition, an ex­cessive liberation could agravate the nutrient lixiviation in vulnerable areas.