Production and benefits in carrot and vegetable cowpea associations under green manuring and spatial arrangements

ABSTRACT The use of a cropping system that provides producers with better land use, higher productivity per unit area, greater diversification in production, and, consequently, agro-economic advantages, is the choice of many vegetable producers. To meet the demands of these producers, experiments were conducted under field conditions in a semi-arid environment to evaluate the production and agro-economic benefits of carrot x vegetable cowpea associations as a function of green manuring with biomass of Merremia aegyptia L., a spontaneous species from the Caatinga biome, in different spatial arrangements at two cropping years. The experimental design was a randomized complete block design with treatments arranged in a 4 x 3 factorial scheme, with four replications. The first studied factor was the amounts of M. aegyptia biomass (20, 35, 50, and 65 t ha-1 on a dry basis), while the second factor was the spatial planting arrangements (2:2, 3:3, and 4:4), corresponding to rows of carrot alternated with rows of vegetable cowpea. The production optimization of the carrot and cowpea cultures was achieved with the incorporation of the M. aegyptia biomass amounts of 32.69 and 50.17 t ha-1, respectively, and agro-economic optimization of the entire intercropping system was obtained at a biomass amount of 34.66 t ha-1. The spatial planting arrangement of 2:2 resulted in the greatest agro-economic efficiency of the crop association.

摘要
可为种植者提供更合理的土地利用模式、更高的单位面积产能、更丰富的生产多样性，进而带来农业经济优势的种植体系，是众多蔬菜种植者的优选方案。为满足此类种植者的需求，本研究在半干旱环境的田间条件下开展试验，以评估胡萝卜与菜用豇豆（vegetable cowpea）间作组合的生产与农业经济效益，本试验以两个种植年度、不同空间配置下，施用卡廷加生物群系（Caatinga biome）野生种埃及鱼黄草（Merremia aegyptia L.）生物质作为绿肥的效果为影响变量。

本试验采用随机完全区组设计（randomized complete block design），处理设置为4×3因子组合，共4次重复。第一研究因子为埃及鱼黄草生物质施用量（干重分别为20、35、50和65 t·ha⁻¹），第二研究因子为种植空间配置（2:2、3:3、4:4，即胡萝卜行与菜用豇豆行交替种植）。

研究结果显示，当埃及鱼黄草生物质施用量分别为32.69 t·ha⁻¹与50.17 t·ha⁻¹时，可分别实现胡萝卜与菜用豇豆的生产优化；当生物质施用量为34.66 t·ha⁻¹时，可获得整个间作体系的农业经济最优效益。采用2:2的种植空间配置时，该作物间作组合可实现最高的农业经济效率。