Green bean under organic and integrated crop systems in a Mediterranean area greenhouse: effects on dry matter and nutrient-extraction distribution pattern.

摘要

The experiment was conducted in two polyethylene greenhouses located in Almeria (Spain) with Mantra green bean crop (Phaseolus vulgaris ssp. volubilis), on a sand-mulched loam soil with trickle irrigation. The experimental design was two factorial with four replications per treatment. The treatments applied were two crop systems, organic (OCS) and integrated (ICS), and two organic-matter levels of soil, 1.0% (low organic-matter soil, LOMS) and 2.5% (high organic-matter soil, HOMS). Nitrogen (N) and potassium (K) were applied by fertigation, and total levels were 68 kg N ha-1 and 107 kg K ha-1 following Regulation (CEE) 2092/91 (Organic Crop System) and Specific Regulation of the Junta of Andalusia (Spain) BOJA 10/01(Green Bean Integrated Crop Production). Total N, phosphorus (P), K, calcium (Ca), and magnesium (Mg) were determined in different plant fractions (fruit, leaf, and stem). Nutrient extraction by plant was significantly greater under ICS (111 kg N ha-1, 36 kg P ha-1, 130 kg K ha-1, 96 kg Ca ha-1, and 30 kg Mg ha-1) than under OCS (78 kg N ha-1, 22 kg P ha-1, 83 kg K ha-1, 71 kg Ca ha-1, and 22 kg Mg ha-1). Extracted nutrient levels did not show significant differences between organic-matter treatments. Nutrient-use efficiency was similar under all treatments. Also the N and Ca patterns between organs were unaffected by treatments, but P, K, and Mg distribution patterns among organs were affected by treatments. In general, N fruit and leaf extractions were similar (around 40%) and greater than N stem. Phosphorus leaf extraction was greater than in stem and fruit. Calcium and Mg extractions were the greatest in leaf (70% and 50%), intermediate in stem (20% and 30%), and the lowest in fruit (10% and 20%). Potassium fruit extraction under ICS was significantly greater (39%) than OCS (35%), whereas K stem extraction under OCS was greater (40%). Similar distribution patterns were found for organic-matter level. Potassium fruit extraction under HOMS was greater, whereas K stem extraction was greater under LOMS.