Silicate and limestone effects on potato nutrition, yield and quality under drought stress

Ca and Mg silicate application can ameliorate soil acidity and increase Ca, Mg, P, and Si availability to plants. Although Si is not an essential nutrient, its application is beneficial for plant growth and development, mainly under stress conditions. This study aimed to evaluate potato nutrition, yield and quality of tuber in a soil amended with limestone and silicate, under two soil moisture conditions. The treatments consisted of dolomitic limestone or Ca and Mg silicate application, at rates calculated to raise the base saturation to 60 %, and at two soil water tensions: 0.020 MPa (without drought stress) and 0.050 MPa (drought stress). The experiment was carried out in a greenhouse in Botucatu, Sao Paulo, Brazil, in pots containing 50 kg dm(-3) of an Acrortox. A completely randomized design in a 2 x 2 factorial arrangement, with eight replications was used. Drought stress had little effect on potato nutrition, but decreased marketable tuber yield. Ca and Mg silicate reached the same levels of soil amelioration and Ca and Mg supply as dolomitic limestone, besides resulting in higher P and Si soil availability and plant uptake. Silicon supply through silicate application to potato induced higher plant height, reduced stem lodging, and higher marketable tuber yield.