Produção de trevo persa em função da época de semeadura e desfolha.

Abstract

The aim of this study was to evaluate Persian clover (Trifolium resupinatum) forage and seed productivity under different sowing dates. The experiment was carried out at Embrapa Clima Temperado - ETB, Pelotas - RS, with the cultivar BRS Resteveiro in a randomized complete block design with four replications. In order to evaluate the harvested forage, five sowing dates were tested (March, April, May, June and July) during two crop years (2014 and 2015). For the evaluation of seed production, besides the five sowing dates, it was also observed the effect of cutting (at the time of the appearance of the first flowers). There was a significant interaction (P <0.05) among the factors sowing time and year for all variables related to forage crop, whereas for the variables related to seed production, there was no interaction only among the factors sowing time and cutting to the variable weight of a thousand seeds. The Persian clover forage crop shows different answers depending on the climatic conditions of each experimental year. When the plants are not subject to cutting, the sowing can occur until the 170th day of the year in order to obtain maximum yields of seed. The plants submitted to cutting are very sensitive to delayed sowing time when the goal is the production of seeds. The delay of sowing time (until the 150th day of the year) and, consequently the cutting, increases the synchronization of flowers maturation and seed physiological quality. However, sowings after the hundredth day of the year, with further cutting intervention, result in insignificant yields of seed.