Produção de brássicas na Região Serrana do Rio de Janeiro: relação entre atributos de solo, práticas de manejo, hérnia das crucíferas e contaminação por metais

Abstract

The vegetables of the Brassicaceae family, demanding in soil fertility, management, and cold climate, have great nutritional and market value. In the State of Rio de Janeiro, its production is concentrated in the mountainous region, on family properties under intensive management, with a typical configuration of mountain agriculture in a tropical region and with reports of environmental impacts and productivity losses due to the occurrence of diseases. Within this context, the present work was developed with the following objectives: 1) Investigate the main aspects, management practices and problems related to the production of kale in a representative region for this crop; 2) to propose and test strategies for soil management, phytotechnics and control of clubroot in the culture of broccoli; 3) to assess the impacts of management practices and inputs on vegetable quality and metal contamination. Initially, samples of soil and kale plants were collected in areas of family production in the region of Petrópolis, RJ, followed by the evaluation of soil attributes, biomass production and intensity of clubroot (Chapter I). There were failures in management that may be contributing to the widespread occurrence of the disease, such as the sequential cultivation of host species and failures in carrying out soil analysis and liming. The disease was more severe in areas with more acidic soils and higher Al3+ content, and water accumulation (greater Topographic Wetness Index - TWI). In Chapter II, management strategies were evaluated to increase the yield of the broccoli culture and reduce the losses caused by clubroot. In the first trial, the incorporation of four types of pre-cultivations (green manure), associated with the use of broccoli seedlings of different sizes, was evaluated. In the second trial, the use of corrective, limestone and steel slag associated with the application of poultry litter, fresh or composted for 45 days, was evaluated. The incorporation of sunn hemp and coriander biomass, and the use of larger seedlings (cell of 35 cm3 and age of 28 days) and (cell of 50 cm3 and age of 32 days), resulted in less intensity of the disease, and greater development of plants and yield. The application of poultry litter increased the intensity of the disease but did not affect the production of broccoli. The application of steel slag did not differ from limestone in correcting acidity and plant development. In Chapter III, the contamination of broccoli plants by toxic metals was analyzed due to the use of steel slag and poultry litter. The levels, translocation and accumulation of metals, and risks to human health associated with the consumption of the produced inflorescences were determined. The metals Pb and Cd were the ones that most collaborate for the non-carcinogenic health risks. In the inflorescences was accumulated 60 to 66% of all absorbed Pb when using steel slag and fresh or composted poultry litter, simultaneously. Based on the calculated indices, it was concluded that the consumption of inflorescences produced with the combined use of these inputs can result in health risks.