Produção orgânica de alface americana fertirrigada com biofertilizantes em cultivo protegido

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Biofertilizers have positive effects on nutrition, postharvest attributes and crop protection, but little is known about its characteristics and real efficiency. Furthermore, application rates commonly used throughout the crop cycle does not attend the growing culture needs satisfactorily. Thus, this study aimed to evaluate the effect of biofertilizers applied via fertigation in nutrition, production patterns and some postharvest attributes of iceberg lettuce produced in protected organic system. The experiment followed a randomized blocks design with a 4 x 4 factorial split block scheme, with five replicates. The main plots were applied four biofertilizers treatments: Agrobio, Bioembrapa, Organic Compost Extract and Control (only water via irrigation and two organic compost cover aplications of 250 g m-2) and the subplots were consisted by four four iceberg lettuce cultivars, OGR 326, Gloriosa, Tainá and Laurel. Biofertilizers and soil characteristics, plant nutritional status, commercial and total media mass head, head circumference, stem length, number of leaves and dry mass were evaluated. Postharvest evaluations were: soluble solid levels, acidity, weight loss, visual aspect of lettuce appearance and leaf nitrate content. Bioembrapa biofertilizer presented higher levels of N and P, while Organic Compost Extract showed K higher levels. Biological contaminant levels overed allowed limits only in the Organic Compost Extract. In general, soil fertility was improved with the application of biofertilizers, and the plant nutritional status was appropriate, despite the high content of potassium and boron in plants fertigated with Agrobio, which caused burning of leaves edges. The biofertilizer Bioembrapa promoved the highest yield of lettuce. There were low levels of soluble solids at harvest and after storage and little weight loss during storage. Regardless the cultivar, visual aspect of lettuce was slightly to moderately damaged after storage and nitrate content in leaves was generally low. Bioembrapa was the best biofertilizer and Organic Compost Extract was the worst one, whose utilization is not recommended to replace biofertilizer in lettuce crop.

ASSUNTO(S)

agricultura orgânica lactuca sativa l nitrato agronomia organic agriculture postharvest attributes estado nutricional lactuca sativa l nitrate fertirrigação nutritional status gotejamento atributos pós-colheita drip-fertigation

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