Nutriente limiting growth of molasses-grass in an oxisol

Abstract

A study was undertaken to determine the nutritional factors limiting the initial growth of molasses-grass in an oxisol, the relative importance of the soil acidity amendment, and to identify reasons for the grass growth in low fertility soils. In a pot trial, the following treatments were compared: complete, check and the omission of either acidity amendment, P and Ca plus Mg, from the "complete". In addition, the roots were sampled at the depths of: 0-2.5, 2.5-5, 5-10, and 10-15 cm. In the same way, the soil was sampled at the depths of: 0-2.5, 2.5-5, 5-10, 10-15, and 15-20 cm, for chemical analysis. It was concluded that P was the main nutrient limiting the initial growth of molasses-grass, followed by Ca. The omission of soil acidity amendment had no effect on the grass dry matter yield. The data also indicated that the persistence of molasses-grass in the field, as a natural pasture, is due mainly to nutrient cycling processes. The rate of nutrient enrichment in the layer of 0-5 cm of soil was most pronounced for available-P, exchangeable-K, and -(Ca + Mg).