Colheita mecanizada de crambe (Crambe abyssinica Hochst) no cerrado Sul-Mato-Grossense

Abstract

Crambe abyssinica Hochst, belonging to brassicaceae family, is a rustic plant that is cultivated in winter because it is tolerant to light frost and drought resistant. Until recently, crambe was used only as soil covering, but due to the high content of oil in grains, it has been cultivated as oleaginous, which oil have been used by cosmetic industry and for biofuel production and production areas had been increased, however, knowledge about seed production is restricted. Among the factors that affect the seed quality are its physiological maturity and harvest process. This work has as aim to evaluate the physiological quality of crambe seeds that were submitted to mechanical harvest. Harvest date of seeds, harvest performance as a function of speed of work and rotation of the threshing cylinder and harvested seed quality were studied. This work was carried out at field in the experimental area of Embrapa Agropecuaria Oeste, located in Dourados-MS, where FMS Brilhante cultivar was cultivated. In the laboratory of Machines and Agricultural Mechanization of UFGD/FCA the laboratory analysis were done. Ten plants from useful area of plot were harvested, green and dried fruits were separated, and water content and specific weight, the weight of 1000 fruits, oil content and seed germination were characterized. In order to study quality and quantity losses, treatments were disposed according randomized block design, in 3 x 4 factorial scheme, which were three speeds of work (3.0, 5.0, 8.2 km h-1) and four rotations of the threshing cylinder (400, 600, 800 and 1000 rpm). Regarding to crambe harvest, it must be done until 105 days after sowing, from this date seed quality decreased and fruit fell by dehiscence. The maximum oil content in seed was obtained in fruits that were harvested on 105.6 DAS, while water content that is considered ideal for seed storage, 8.7%bu, occurred on 109 DAS. The highest harvest capacity was obtained with the increase of feeding rate and speed of work, independent on the rotation of threshing cylinder. The smallest losses for combine header were observed for 5.04 km h-1 speed and for 650 to 1000 rpm of rotation of threshing cylinder, while the losses for internal mechanisms and total losses were smaller for 5.04 km h-1 speed of work and when the rotation of threshing cylinder was between 700 and 900 rpm. In general, it is recommended speed of 5.04 km h-1 and rotation of 800 rpm in order to obtain the smallest losses in crambe harvested when fruits were completely dried. In relation to seed quality, the increase of the rotation of threshing cylinder reduced its vigor and promoted increase of impurity rate and mechanical damages. The smallest percentage of mechanical damage, the highest vigor and oil production of crambe seeds were obtained with the highest speed of work.