ABSTRACT: Optimization of symbiosis between nitrogen-fixing bacteria and legumes has been extensively studied, seeking agricultural sustainability. To evaluate the symbiotic efficiency of nitrogen-fixing bacterial strains belonging to the Bradyrhizobium genus with pigeon pea (Cajanus cajan (L.) Millsp.) cv. Fava-Larga, experiments were conducted in Leonard jars (axenic conditions), pots with soil, and in the field. Ten strains were tested in Leonard jars, and three strains, in addition to BR 29, were selected according to their ability to promote the growth of […]

In a no-tillage system, cover crops must be used that combine shoot dry matter production and nutrient recycling. The aim of this study was to evaluate shoot dry matter production, decomposition rate and macronutrient and silicon release from pigeonpea and pearl millet in monoculture and intercropping systems. A randomized block design was used with a 3 x 6 factorial arrangement, with four replications. The first factor consisted of three cover crops (pigeonpea, pearl millet and intercropping of these cover crops) […]

In the humid tropics the buildup and maintenance of soil fertility are major challenges in terms of sustainability of agroecosystems. The objective of this study was to evaluate an alley cropping system with pigeon pea (Cajanus cajan) on an Alfisol, with annual application of lime and potassium, with special concern regarding the viability of this system as an alternative to slash and burn practiced in tropical agriculture. Pigeon pea and maize (Zea mays) were planted in the experiment with the […]

The aim of this study was to select and partially characterize efficient nitrogen-fixing rhizobia associated to pigeonpea from coastal tableland areas in the Northeast of Brazil. Sixteen rhizobia from different coastal tableland areas were evaluated under greenhouse condition, at the Embrapa Coastal Tablelands (Aracaju, Sergipe, Brazil). Four isolates performed better than the others in relation to shoot N content (NC), shoot dry weight (SDW), leaf area (LA) and nodule dry weight (NDW). NDW showed high correlation with SDW, LA and […]

Planting spacings and sowing dates may influence nutrient absorption. Therefore, a field experiment was carried out from 1991 to 1992, at the experimental station of Embrapa/Soil Research National Center, located in Senador Canedo, Goiás, Brazil, to determine the N, P and K uptake levels in the aerial part of sunhemp (Crotalaria juncea), Crotalaria ochroleuca, black velvet bean (Mucuna aterrima) and pigeonpea cv. Kaki (Cajanus cajan), under three sowing times (beginning, middle and end of the growing season) and two spacings […]