Green manuring with Calotropis procera for the production of coriander in two growing seasons
ABSTRACT The use of spontaneous species of the Caatinga biome can contribute significantly to the nutritional demand of vegetable crops, thereby providing an agroecological and sustainable form of production. The objective of this research was to determine the effects of different biomasses of Calotropis procera (rooster tree) and times of incorporation into the soil of green manure during two growing seasons on the agronomic performance of coriander cv. Verdão produced in Serra Talhada, a semi-arid region of Pernambuco, Brazil. The experimental design was randomized blocks with three replications. The treatments were arranged in a 4 x 4 factorial scheme, with the first factor consisting of biomass amounts of C. procera (5.4, 8.8, 12.2 and 15.6 t ha-1 on a dry basis) and the second by the incorporation times into the soil (0, 10, 20 and 30 days before coriander planting). The evaluated characteristics were plant height, number of stems per plant, yield of green mass and dry mass of shoot. The best productive performance of coriander was observed in amounts of 12.2 (spring) and 8.8 (autumn-winter) t ha-1 C. procera added to the soil, with an ideal incorporation time of 13 (spring) and 23 (autumn-winter) days before sowing of the crop and with larger accumulations of green and dry mass of the shoot being obtained in autumn-winter.