Adubação fosfatada no desenvolvimento e produção de feijão guandu em latossolo vermelho do cerrado em primeiro cultivo / Phosphorus fertilization on the development and production of pigeonpea in the cerrado oxisol in first cultivation

O fósforo é um importante macronutriente, requerido por todas as plantas para crescimento, desenvolvimento e reprodução, sendo o fator de produção mais importante para a agricultura após a calagem em solos sob vegetação de Cerrado. Assim, objetivou-se avaliar o desenvolvimento e produção do feijão guandu submetido à adubação fosfatada, sem inoculação de sementes, em Latossolo Vermelho do Cerrado em primeiro cultivo. O experimento foi conduzido em casa de vegetação no período de agosto a novembro de 2010. Utilizaram-se vasos contendo 3 dm-3 de solo coletado na profundidade de 0-0,20 m em área de Cerrado. O delineamento experimental foi inteiramente casualizado, com seis doses de fósforo (P2O5): 0; 50; 100; 150; 200 e 250 mg dm-3 em quatro repetições. Houve efeito significativo a 5% de probabilidade para todas as variáveis avaliadas com ajuste aos modelos quadrático e linear de regressão. O melhor desenvolvimento e produção de feijão guandu ocorre no intervalo de doses de fósforo de 162 a 225 mg dm-3. O feijão guandu responde de forma positiva a adubação fosfatada, sem a inoculação de sementes em Latossolo Vermelho do Cerrado em área de primeiro cultivo.

Phosphorus is an important macronutrient required by all plants for growth, development and reproduction, and the most important production factor for agriculture after liming in soils under Cerrado vegetation. Thus, the objective was to evaluate the development and production of pigeonpea subjected to fertilization without inoculation of Cerrado Oxisol in first cultivation. The experiment was conducted in a greenhouse in August-November 2010. We used 3 dm3 pots containing soil collected at 0-20 cm depth in the Cerrado. The experimental design was completely randomized design with six levels of phosphorus (P2O5): 0; 50; 100; 150; 200, e 250 mg dm-3 with four replications. There was a significant effect at 5% probability for all variables adjusted for the quadratic and linear regression. The best development and production of pigeonpea occurs within phosphorus levels of 162 the 225 mg dm-3. The pigeonpea respond positively to fertilization, without the inoculation of seeds in the soil of the Cerrado in first cultivation area.

Infectivity and efficacy of Glomus aggregatum and growth response of Cajanus cajan (L.) Millsp. in flyash amended sterile soil.

In the present investigation a pot culture experiment was conducted using sterile, phosphorus deficient soil to study the effect of flyash at 3 different concentrations (10g, 20g and 30g flyash/kg soil) on the infectivity and effectiveness of VAM fungus Glomus aggregatum in pigeonpea (Cajanus cajan (L.) Millsp.) cv Maruti. The flyash amendment in soil at all the 3 different concentrations was found to affect significantly the intensity of VAM fungal colonization inside the plant roots and also suppressed the formation of VAM fungal structure (vesicles and arbuscules) completely at higher concentration (30g flyash/kg soil). The response of the pigeonpea plants, as judged by their higher and dry weight, under the influence of flyash amendment in VAM fungus infested soils was found to be considerably less (though not significant enough) when compared to the control plants (without flyash) that have otherwise shown significant increase in growth over the plants without Glomus aggregatum inoculation. However, flyash amendment without VAM inoculation was also found to enhance the growth of plants as compared to control plants (without flyash and VAM inoculum).

Biological control of Fusarium wilt of pigeonpea Cajanus cajan (L.) Millsp with chitinolytic Alcaligenes xylosoxydans.

Alcaligenes xylosoxydans protected pigeonpea from Fusarium wilt in a pot experiment and field trials. When seeds of pigeonpea (C. cajan) were treated with A. xylosoxydans and sown in soil infested with Fusarium, the incidence of wilt was reduced by 43.5% and resulted in 58% higher grain yield. The antifungal activity of A. xylosoxydans was based on chitinase production and was comparable in efficacy to commercial antifungal agents such as benlate, monitor WP, thiram and bavistin.