Relação cálcio e magnésio em alfafa cultivada em casa de vegetação

Abstract

ABSTRACT: Alfalfa is a forage of great importance in animal feed, used in the creation of specialized herds due to its high protein content, besides having high palatability and high energy value. In this context, the objective of this research is to evaluate the effect of calcium and magnesium ratio on the correction of oxisol for alfalfa (Medicago sativa) cv. Creole. The experiment was conducted in a greenhouse at the Federal University of Mato Grosso, in Rondonópolis - MT. The experimental design was completely randomized with 9 treatments of calcium/magnesium (0/0, 1/0, 0/1, 3/1, 6/1, 9/1, 12/1, 15/1 and 18/1) with 5 replications, totaling 45 experimental units. The variables analyzed were: plant height, number of leaves, number of tillers, SPAD, stem diameter, fresh mass of the aerial part, dry mass of the shoot part, root volume, root dry mass and water use efficiency. The results were submitted to analysis of variance and Scott-knott's test, both at 5% probability, by SISVAR software 5.6. In the first cut, the height of the plants obtained higher height in the ratio 6/1 (40.42 cm) and in the second cut the highest height was in the treatment 18/1 (55.29 cm). In the fresh mass of the aerial part, significant differences were observed in the two cuts, in the first cut the highest mass found was 6/1 (18,172g) and in the second cut, the ratio with the highest mass was 3/1 (20.8g). Regarding the dry mass of the shoot part, in the first cut it was observed a greater mass in the treatment 18/1 (3.28g) and in the second cut, the dose with greater mass was also 3/1 (5.56g). In relation to the root volume the treatment that provided the largest volume was 12/1 (48.8 mL). In the dry mass of root, the ratio that obtained the largest mass was 18/1 (7.52 g). The SPAD obtained significance only in the first cut, in which the treatment that provided the highest chlorophyll index was 1/0 (49,9). Regarding the pH, it was observed that even after liming, in the second cut it decreased pH, both using as a reagent calcium chloride and deionized water. Alfalfa is not influenced by the different doses of calcium and magnesium.