The responses in yield of crops are related to fertilization and pest management. The objective of the experiment was to compare the yield of onion in organic and conventional system, under minimum tillage, related to nutritional and plant health aspects. Two experiments were carried out, in 2011 and 2012, over an Haplumbrept soil at Ituporanga, Santa Catarina state, Brazil. In 2011 we established the following treatments: CONV (conventional mineral fertilizer and pesticides), AM/CB (mineral fertilizer and Bordeaux mixture (CB 0.3%)\, AO (organic fertilizer without pest management); AO/CB [organic fertilizer and CB 0.3%); AO/CB/BF-3% [organic fertilizer, CB 0.3% and biofertilizer sprayed liquid of cow manure (PBEB 3%)\; AO/CB/BF-5% (organic fertilizer, CB 0.3% and PBEB 5%); AO/CB/BF-10% (organic fertilizer, CD 0.3% and PBEB 10%). In 2012, we included the AM treatment (mineral fertilizer without pest management). We used the Empasc 352 Bola Precoce cultivar. The seedlings were transplanted in July 21, 2011 and July 9, 2012, and the harvests were made in November 21, 2011 and September 9, 2012, respectively. The CONV treatment was 39% more productive than the average organics with Bordeaux mixture and biofertilizers. Indirect measurements of chlorophyll were influenced by cycle phase and water stress. The water stress reduced the marketable yield in 43% on organic system and 34% in CONV. Biofertilizers did not provide nutrients, especially N, in the required amounts by plants. Also, they did not alter the nutritional quality, content and nutrient uptake by the bulbs, and did not reduce the incidence of thrips and downy mildew in onions.
Allium cepa; chlorophyll; nutrition; plant health and nutritional quality.
