Bactérias promotoras de crescimento de plantas como atenuantes do déficit hídrico em milho verde.

Abstract

Corn is one of the most expressive crops in agribusiness in Brazil and in the world due to its versatility of use, both in human and animal feed. In the Brazilian semiarid region, green maize productivity is still relatively low compared to other regions of the country, due to the non- adoption of new production technologies and, mainly, to the water deficit. The objective was to evaluate gas exchange, water use efficiency, mineral nutrition of green corn as a function of bioinoculants containing plant growth - promoting bacteria (PGPB) and Co + Mo, as well as their influence on the availability of P and N in the ground. An experiment was carried out under field conditions with the green maize cultivar AG 1051, in spatially subdivided plots, where the plots consisted of three irrigation depths (60, 80 and 100% of ETc) and the subplots corresponded to four treatments based on BPCP and Co + Mo (C: control, without bioinoculant; T1: Bacillus subtillis; T2: Bacillus amyloliquefaciens plus Azospirillum brasiliensis and T3: Co + Mo, solution with 0.3% Co and 10% Mo. Bioinoculants containing PGPB or Co + Mo did not interfere in the rate of CO2 assimilation or in the efficiency of water use in green corn. PGPB, especially B. amyloliquefaciens plus A. brasiliensis and B. subtillis promoted an improvement in the nitrogen nutrition of corn with the increase in total N and mineral N content in leaf tissues, but did not change P and K content. Bioinoculants B. subtilis and Co + Mo increased mineral N content and soluble and organic P content in the soil. most severe water stress level (60% of ETc), promoted a greater efficiency in the use of water for the production of vegetative fresh mass.