ABSTRACT. The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

A operação de colheita é considerada uma das mais importantes na produção de sementes de algodão, devido a qualidade e o tipo de produto dependerem do modo e do momento em que é realizada. Foi conduzido este trabalho com o objetivo de avaliar a influência do horário de colheita na qualidade de sementes do algodoeiro, cultivar CNPA 7H, produzidas e colhidas em seis horários (7:00, 9:00, 11:00, 13:00, 15:00 e 17:00 horas) e três microrregiões do Estado da Paraíba: Tacima (Curimataú Oriental Paraibano), Guarabira (Piemonte da Borborema), em condições de sequeiro, e Diamante (alto sertão paraibano), em condições irrigadas. As sementes, foram avaliadas quanto ao grau de umidade, germinação e vigor (teste de frio e índices de velocidade germinação e de emergência em campo), além da sanidade. Fez-se uma análise de variância conjunta considerando o efeito dos horários de colheita e locais de produção. Os maiores valores de germinação e de vigor foram obtidos no campo de Tacima nos horários entre 9:00 e 15:00 horas. Sementes do algodoeiro colhidas às 7:00 e 17:00 horas apresentaram menor qualidade fisiológica, nos três campos de produção. As sementes produzidas sob condições irrigadas, apresentaram maior ocorrência fúngica, principalmente para os gêneros Aspergillus e Fusarium.

The operations realized at harvest are important when the aim is to obtain seeds with good qualities and these processes are affected by the manner and time of their realization. This study was carried out investigate the influence of the harvest time on the quality of seeds of cotton produced in three microregions of Paraíba state. Cotton seeds, cultivar CNPA 7H, collected at different times (7:00, 9:00, 11:00, 13:00, 15:00 and 17:00 hours) and in different microregions of the state of Paraíba, Curimataú Oriental Paraibano (Tacima), Piemonte da Borborema (Guarabira) and Alto Sertão Paraibano (Diamante) were submitted to determination of the moisture content and evaluations of germination and vigour (cold test, speed of germination and field emergence). The sanitary analysis (fungi) was also performed. In the statistical analysis at first the data were considered individually of the effect of the microregions and then another analysis was done considering the effect of harvest times versus microregions. The highest values of germination and vigour were obtained in the Tacima fields which were harvest between 11:00 and 15:00 hours. Cotton seeds collected at the first (7:00) and last (17:00) times showed the least physiological quality in the three production fields. Seeds produced in Tacima presented the best physiological quality. The seeds produced in the Diamante had the highest fungi incidence, mainly of fungi of the Aspergillus flavus and Fusarium sp species.