Yield of weeping lovegrass (Eragrostis curvula (Nees) cv. Ermelo), as a function of soil properties. | Rendimiento de pasto llorón, Eragrostis curvula (Nees) cv. Ermelo, en función de algunas propiedades edáficas

The relationship between the yield of weeping lovegrass and some edaphic properties of 18 soils in a large area which includes the districts of Bahia Blanca, Villarino, Than and Saavedra in the province of Buenos Aires and the district of Hucal in the province of La Pampa, Argentina, was studied. Work was carried out in pots with a net content of 2.5 to 15 kg of soil and 3 plants per pot in a randomized block design with 3 repetitions. Three cuts were made, with a span of 75 days between each, and the yield of dry natter in gams per pot was determined.The properties of the soils analyzed were total nitrogen, organic carbon, organic matter, exchangeable calcium, magnesium, potassium and sodium, percent of exchangeable sodium (PSI), sodium adsorption ratio (RAS), cation exchange capacity, available phosphorus, nitrate nitrogen, carbon-nitrogen ratio, texture, pH, equivalent humidity and electrical conductivity. The incidence of these properties on the crop yield was analyzed by means of stepwise multiple regression. The edaphic properties significantly associated with the total aerial biomass in multiple correlations, in order of importance, were. total nitrogen, nitrate nitrogen, percent of exchangeable sodium, exchangeable magnesium, equivalent humidity, clay content, organic carbon content, carbon-nitrogen ratio, sand content, pH, calcium and potassium (R = 0.95) The exchangeable magnesium was included due to the effect caused by soil number 16 which presented a higher content of this cation than other soils. A new multiple regression analysis without this soil gave the following variable sequence: total nitrogen, nitrate nitrogen, electrical conductivity, clay, silt, organic matter, carbonnitrogen ratio, percent of exchangeable sodium and sodium adsortion ratio (R = 0.97). To predict crop responses it is recommended that only the first 4 variables in the equation which includes all soils and the first 3 variables in the equation excluding soil number 16 be considered.