Sugarcane (Saccharum spp.) is one of the most important crops in the world. Throughout the sugarcane’s growth stages, periods of drought are common, causing detrimental effects on plant growth. Therefore, the search for strategies for minimizing the impact of drought on sugarcane development is of great interest. Plant growth-promoting bacteria hold the potential for improving tolerance to drought in agricultural systems. Thus, the present study aimed to evaluate whether inoculation with Bacillus subtilis can reduce the negative effects of drought on the nutritional, physiological, and morphological characteristics of sugarcane plants. For this, sugarcane was cultivated in a greenhouse, under controlled conditions of water and temperature, with the aid of four treatments: without and with inoculation of B. subtilis, in normal conditions of water availability, and in conditions of water restriction (2 × 2 factorial), with four replications. In treatments with inoculation, the pre-emerged seedlings were immersed in a B. subtilis solution and transplanted into experimental pots. Our results showed that inoculation with B. subtilis improved plant nutrition and chlorophyll concentrations. As a result, the gas exchange parameters (especially net photosynthetic rate and water use efficiency) were also improved, even under drought conditions. In addition, stress parameters (antioxidant metabolism activity) were reduced in inoculated plants. The sum of these beneficial effects resulted in increased root growth, tillering, stalk weight, and higher sucrose concentration in the stalks.

(1) Background: The aim of this study was to explore whether supplementary magnesium (Mg) foliar fertilization to soybean and maize crops established in a soil without Mg limitation can improve the gas exchange and Rubisco activity, as well as improve antioxidant metabolism, converting higher plant metabolism into grain yield. (2) Methods: Here, we tested foliar Mg supplementation in soybean followed by maize. Nutritional status of plants, photosynthesis, PEPcase and Rubisco activity, sugar concentration on leaves, oxidative stress, antioxidant metabolism, and finally the crops grain yields were determined. (3) Results: Our results demonstrated that foliar Mg supplementation increased the net photosynthetic rate and stomatal conductance, and reduced the sub-stomatal CO₂ concentration and leaf transpiration by measuring in light-saturated conditions. The improvement in photosynthesis (gas exchange and Rubisco activity) lead to an increase in the concentration of sugar in the leaves before grain filling. In addition, we also confirmed that foliar Mg fertilization can improve anti-oxidant metabolism, thereby reducing the environmental stress that plants face during their crop cycle in tropical field conditions. (4) Conclusions: Our research brings the new glimpse of foliar Mg fertilization as a strategy to increase the metabolism of crops, resulting in increased grain yields. This type of biological strategy could be encouraged for wide utilization in cropping systems.

The alternative technique of co-inoculation or mixed inoculation with symbiotic and non-symbiotic bacteria has been studied in leguminous plants. However, there are few field studies with common beans and under the influence of the amount of irrigated water. Thus, the objective of this study was to evaluate the efficiency of inoculation and co-inoculation of common beans with Rhizobium tropici and Azospirillum brasilense under two irrigation depths. The experiment was carried out in the winter of 2012 and 2013, in Selvíria, state of Mato Grosso do Sul. The experimental design was composed of randomized blocks in split-plot scheme with two irrigation depths in the plots (recommended for common beans and 75% of the recommended) and five forms of nitrogen (N) supply in the split-plots (control non-inoculated with 40 kg ha- 1 of N in topdressing, 80 kg ha- 1 of N in topdressing, A. brasilense inoculation with 40 kg ha-1 of N in topdressing, R. tropici inoculation with 40 kg ha-1 of N in topdressing, and co-inoculation of A. brasilense and R. tropici with 40 kg ha- 1 of N in topdressing) with four repetitions. Co-inoculation increased nodulation in the second year of cultivation. None of the evaluated treatments increased the grain yield in relation to non-inoculated control with 40 kg ha-1 of nitrogen in topdressing, which presented average yield of 2,200 kg ha-1. The use of 75% of the recommended irrigation depth provides similar grain yield to the recommended irrigation depth in common beans cropped in winter

The productive potential of new peanut cultivars has increased over the years in relation to old cultivars, especially when compared with ones with upright growth habit. Thus, the requirement for macronutrients for these new cultivars may also have increased, making the existing fertilizer recommendation tables obsolete, thus increasing the need for further studies measuring the real macronutrient requirements of these new peanut cultivars. Our study aimed to evaluate the growth patterns and the macronutrient absorption rate throughout the biological cycle of three modern runner peanut cultivars, as well as the potential for producing dry matter, pods, and kernels, and their respective macronutrient accumulations. The experimental design was a randomized complete block with split-plots and nine replications. The experimental plots consisted of three peanut cultivars (IAC Runner 886, IAC 505, and IAC OL3), and subplots consisted of nine plant samplings (14, 28, 42, 56, 70, 84, 105, 126, and 147 days after emergence (DAE)). Our results showed that modern peanut cultivars presented nutrient accumulation around 30 to 40 days earlier than older cultivars, as well as increasing the uptake by K and Ca. IAC 505 absorbed higher amounts of macronutrients and resulted in greater dry matter production compared with IAC OL3 and IAC Runner 886. Our study demonstrated that the most appropriate time for plants to find greater availability of nutrients in the soil is 70 to 84 DAE, in addition to highlighting the need for updates on nutritional recommendations for higher yields of modern peanut cultivars.

Este trabalho objetivou avaliar a influência de fontes, épocas e doses de nitrogênio em cobertura no milho cultivado em sistema plantio direto. O experimento foi conduzido em Selvíria, MS, Brasil (20º 20’ S e 51º 24’ W), durante o ano agrícola 2010/11, sob Latossolo Vermelho Distrófico típico argiloso. O delineamento experimental foi o de blocos ao acaso, com os tratamentos dispostos em esquema fatorial 2 x 2 x 4, com quatro repetições. Como fontesde nitrogênio, utilizaram-se ureia e sulfato de amônio e as aplicações realizadas nos estádios de desenvolvimento V5 e V8. As doses testadas foram: 0; 50; 100 e 150 kg ha-1 de N.