Adubação foliar de sulfato de zinco na produtividade e teores foliares de zinco e fosforo de cafeeiros arábica

Aiming to evaluate the dose and application schedule of foliar Zn-sulfate spraying in growing and yield of Arabic coffee Mundo Novo, a field experiment was set up on Distroferric Red Latosol, at the Experimental Station of the EPAMIG in São Sebastião do Paraíso. The statistical design used was randomized blocks in s 4 x 2 factorial scheme with five replications and a 30-plant plot with six central valid or four applications per agricultural year. Phosphorus and zinc leaf levels were evaluated for eight years and the yields. It was possible to conclude that there is a positive response to the in the leaves. Four low concentrations sprayings promoted higher yields than two high concentrations. The highest yields were achieved with 10.8 and 12.6 kg ha-1 of ZnSO4 and 4 yearly applications, respectively. It is suggested as a critical range for the Zn leaves values between 10 and 28 mg kg-1 and for P/Zn ratio, between 100 and 150. ) was sprayed under 4 concentrations 0; 0.5; 1.0 and 1.5%, two applied on the leaves in terms of yield, and to Zn levels

Nutrients distribution in diseased coffee leaf tissue

Knowing the structure and distribution of nutrients in plant tissues can clarify some mechanisms of pathogen attack in plants and plant defense against infection, thus helping management strategies. The aim of this study was verify differences in distribution of mineral nutrients in coffee leaf tissues around foliar lesions of bacterial blight of coffee, blister spot, cercospora leaf, phoma leaf spot and coffee leaf rust. Fragments of leaf tissue surrounding the lesions were dehydrated in silica gel, carbon covered and subjected to X-ray microanalysis (MAX). Thirty-three chemical elements were detected in leaf tissue; however, there was variation in potassium and calcium contents surrounding the lesions. The highest potassium content was found in asymptomatic tissues surrounding the lesions, decreasing toward the transition zone and reaching minimum content in symptomatic tissues. The highest calcium content was found in symptomatic tissues, decreasing toward the transition zone and reaching minimum content in asymptomatic tissues. Therefore, MAX can be used to analyze the composition and distribution of nutrients in plant tissues and, if associated with mineral nutrition, it may help understand host-pathogen relationships and plant disease management.

Spatial distribution of Yellow Sigatoka Leaf Spot correlated with soil fertility and plant nutrition

This study analyzed the spatial distribution of Yellow Sigatoka Leaf Spot relative to soil fertility and plant nutritional status using geostatistics. The experimental area comprised 1.2 ha, where 27 points were georeferenced and spaced on a regular grid 18 × 18 m. The severity of Yellow Sigatoka, soil fertility and plant nutritional status were evaluated at each point. The spherical model was adjusted for all variables using restricted maximum likelihood. Kriging maps showed the highest infection rate of Sigatoka occurred in high areas of the field which had the highest concentration of sand, while the lowest disease was found in lower areas with lower silt, organic matter, total exchangeable bases, effective cation exchange capacity, base saturation, Ca and Mg in soil, and foliar sulfur (S). These results may help farmers manage Yellow Sigatoka disease more effectively, with balanced fertilization and reduced fungicide application. This practice minimizes the environmental impact and cost of production while contributing to production sustainability.