Cutting frequencies and defoliation intensities on two alfalfa (Medicago sativa, L) cultivars. 1. weight, number, seasonal production and dynamic of appearance of basal shoots

[摘要] - The experiment was carried out at Piracicaba, SP, over one year, with two alfalfa cultivars (Crioula and CUF-101) grown in pots at open field. The weight and the basal shoot numbers were evaluated. The regrowth dynamics after the cut and seasonally of production using three cutting frequencies, 28, 35 and 42 days, and three defoliation intensities, cuts at 7 cm height with or without preservation of remaining leaf area and cut at soil level were evaluated. A completely randomized experimental design in a 3 x 3 x 2 factorial arrangement (cultivar, cut frequency and defoliation intensity), with three replications, was used. To evaluate the seasonal production, in the three alone frequency, a split plot experimental design over time was used, in which the whole plot were represented by the treatments (cultivar vs. defoliation intensity) and the split by the cuts. The 28 days cut frequency was the best for both cultivars for dry matter yield of shoots/pot, mainly in the summer time. As for shoot numbers, cut frequencies of 28 and 35 days were superior to 45 days cut frequency. Defoliation intensity of 7 cm, with preservation of the remaining leaf area, was superior to the other, as for weight and shoots numbers. The summer time showed to be favorable to production of these alfalfa cultivars. As for the appearance of regrowth shoots, more than 2/3 of shoots appeared in the two subsequent weeks after the cut, independently of cut frequency and of defoliation intensity. In tropical conditions, there is a possibility to obtain high yields with alfalfa plants since the use of about 28 days of cut intervals has to be observed. In addition, cuts closely to 7 cm from soil level are favorable, in order to explore the photosynthetic ability of the remaining leaf area and of the regrowth shoots present in the moment of cut.

[学科分类] 兽医学

[关键词] alfalfa;cultivar Crioula;cultivar CUF-101;cutting management    Introdução A alfafa (Medicago sativa;L