A successful microbial inoculant can increase root colonization and establish a positive interaction with native microorganisms to promote growth and productivity of cereal crops. Zinc (Zn) is an intensively reported deficient nutrient for maize and wheat production in Brazilian Cerrado. It can be sustainably managed by inoculation with plant growth-promoting bacteria and their symbiotic association with other microorganisms such as arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE). The objective of this study was to evaluate the effect of Azospirillum brasilense inoculation and residual Zn rates on root colonization and grain yield of maize and wheat in succession under the tropical conditions of Brazil. These experiments were conducted in a randomized block design with four replications and arranged in a 5 × 2 factorial scheme. The treatments consisted of five Zn rates (0, 2, 4, 6 and 8 kg ha⁻¹) applied from zinc sulfate in maize and residual on wheat and without and with seed inoculation of A. brasilense. The results indicated that root colonization by AMF and DSE in maize–wheat cropping system were significantly increased with interaction of Zn rates and inoculation treatments. Inoculation with A. brasilense at residual Zn rates of 4 kg ha⁻¹ increased root colonization by AMF under maize cultivation. Similarly, inoculation with A. brasilense at residual Zn rates of 2 and 4 kg ha⁻¹ reduced root colonization by DSE under wheat in succession. The leaf chlorophyll index and leaf Zn concentration were increased with inoculation of the A. brasilense and residual Zn rates. The inoculation did not influence AMF spore production and CO₂-C in both crops. The grain yield and yield components of maize–wheat were increased with the inoculation of A. brasilense under residual Zn rates of 3 to 4 kg ha⁻¹ in tropical savannah conditions. Inoculation with A. brasilense under residual Zn rates up to 4 kg ha⁻¹ promoted root colonization by AMF and DSE in the maize cropping season. While the inoculation with A. brasilense under 2 and 4 kg ha⁻¹ residual Zn rates reduced root colonization by AMF and DSE in the wheat cropping season. Therefore, inoculation with A. brasilense in combination with Zn fertilization could consider a sustainable approach to increase the yield and performance of the maize–wheat cropping system in the tropical savannah conditions of Brazil.

Composted sewage sludge (CSS) is an organic fertilizer that can be used as a source of micronutrients in agriculture. However, there are few studies with CSS to supply micronutrients for the bean crop. We aimed to evaluate micronutrient concentrations in the soil and their effects on nutrition, extraction, export, and grain yield in response to CSS residual application. The experiment was carried out in the field at Selvíria-MS, Brazil. The common bean cv. BRS Estilo was cultivated in two agricultural years (2017/18 and 2018/19). The experiment was designed in randomized blocks with four replications. Six different treatments were compared: (i) four increasing CSS rates, i.e., CSS5.0 (5.0 t ha⁻¹ of applied CSS, wet basis), CSS7.5, CSS10.0, CSS12.5; (ii) a conventional mineral fertilizer (CF); (iii) a control (CT) without CSS and CF application. The available levels of B, Cu, Fe, Mn, and Zn were evaluated in soil samples collected in the 0–0.2 and 0.2–0.4 m soil surface horizons. The concentration, extraction, and export of micronutrients in the leaf and productivity of common beans were evaluated. The concentration of Cu, Fe, and Mn ranged from medium to high in soil. The available levels of B and Zn in the soil increased with the residual rates of CSS, which were statistically not different from the treatments with CF. The nutritional status of the common bean remained adequate. The common bean showed a higher requirement for micronutrients in the second year. The leaf concentration of B and Zn increased in the CSS7.5 and CSS10.0 treatments. There was a greater extraction of micronutrients in the second year. Productivity was not influenced by the treatments; however, it was higher than the Brazilian national average. Micronutrients exported to grains varied between growing years but were not influenced by treatments. We conclude that CSS can be used as an alternative source of micronutrients for common beans grown in winter.

Ornamental lawns, such as Emerald grass (Zoysia japonica), require adequate fertilization management for their development, as well as the substrate used as a base in cultivation is of great importance to improve the aesthetic quality of the species. These two factors together, can provide a better acceptance of the turfgrass, through sensory analysis. Thus, the objective of this study was to evaluate the aesthetic and sensory quality of the Emerald grass, as a function of cultivation on substrates and mineral fertilization. The work was carried out from September to December 2012, in a 5x3 factorial scheme [5 substrates x (2 fertilizers + control)], with 3 repetitions. Emerald grass mats were implanted in 8.5 L containers, filled with 5 substrates: S1 = soil, S2 = soil + sand (2:1), S3 = soil + organic compost (1:1), S4 = soil + compost organic + sand (2:1:1) and S5 = compost + sand (3:1). And the fertilizers used were based on a NPK formulation (10-10-10) applying 60 g m-2, and 125 g m-2 of a commercial product. Were evaluated: lawn height, relative chlorophyll index, dark green color index, and sensory analysis for appearance and color attributes and acceptability index. It was observed that the substrates based on organic compost presented the best results for the evaluated parameters, and the fertilizations carried out with the commercial product and the formulated NPK, presented similar results in the grass development evaluations, while the sensorial analysis is an important tool for accepting the aesthetics of a lawn.

The sewage sludge is a low-cost material and sustainable alternative to substitute chemical fertilizers on ornamental lawns and gardens. Thus, the objective was to evaluate the effects of the application of sewage sludge on the regrowth and ornamental traits of DiscoveryTM bermudagrass. The experiment was carried out during the fall/winter of 2019. The turf was removed and left the soil exposed for a new grass regrowth. The treatments applied were 0, 357, 714, 1,071 and 1,428 g m-2 sewage sludge spread evenly on the lawn in a single dose. The evaluations were carried out after 120 days and the soil solution (EC and NO3 -), Normalized difference vegetation index, root length, root + rhizome + stolon + leaves volume and digital image analysis were evaluated. The results showed that the increase of sewage sludge positively influenced the turfgrass development, both in the aesthetic aspect and on bermudagrass regrowth. The soil solution can show that the sludge increased the electrical conductivity and NO3- ions; however, it did not hinder the development of the lawn, even having positive correlations between these variables and the biometric evaluations of the plant. It is concluded that the dose of 1,428 g m-2 presented the best results for the evaluated characteristics, being the recommended one for use in the fertilization of bermudagrass DiscoveryTM.

DiscoveryTM bermudagrass has been used in ornamental and sporty low-traffic turfgrass, due to its intense green coloring and slow growth, as an alternative in the search to reduce maintenance costs, such as cutting and nitrogen fertilization. However, little is known about fertilization recommendations in winter seasons, especially nitrogen fertilization. In this sense, the objective was to evaluate different doses of N in the development of bermudagrass DiscoveryTM in winter. The experiment was carried out during the winter, in an area with DiscoveryTM lawn already implemented. The design was entirely causalized, with 5 doses of N (0, 15, 30, 45 and 60 g N m-2) through the application of urea, with four repetitions, using 20% of the doses, according to crop requirement for winter, in a single application. The evaluated parameters were green color index (GCI), (Scout CM-1000 and Scout TCM 500), height, dry mass, traction and analysis by digital image of the lawn. It was observed that with the increase of N doses there was an increase in biometric assessments, however the analysis by digital image showed uneven results, and the traction of the lawn did not differ between treatments. Larger doses provided a better visual aspect of the lawn, but for the economic aspect, it is concluded that the use of 20% of the doses between 30 and 40 g N m-2, applied only once during the winter, is more recommended for the development of the DiscoveryTM bermudagrass.

Large quantities of cover crop residues in the soil, combined, or not, with the inoculation of seeds with diazotrophic bacteria, can increase organic matter (OM) and protect soil microorganisms, such as arbuscular mycorrhizal fungi (AMF) and dark septate endophytic (DSE) fungi. Thus, the use of these sustainable biotechnologies can benefit microbial interactions, soil fertility and rice production in the Brazilian Cerrado region. In this study, we evaluated the effects of maize and Urochloa ruziziensis, intercropped or individually, as cover crops and an inoculation of Azospirillum brasilense on the chemical (fertility) and biological (C–microbial biomass and C–CO₂ released) attributes of soil and the effects of root colonization by AMF and DSE on the yield of rice grown in succession in highlands. The experiment was conducted under field conditions, in a typical dystrophic Red Oxisol. The experimental design consisted of randomized blocks arranged in strips, incorporating a combination of eight residual cover crops: ((1) maize, (2) maize–I (I = inoculation of seeds with A. brasilense), (3) Urochloa (U. ruziziensis), (4) Urochloa–I, (5) maize + Urochloa–I, (6) maize + Urochloa–I, (7) maize–I + Urochloa and (8) maize–I + Urochloa–I). This was accompanied by two treatments of rice as a successor crop (inoculated or not with A. brasilense), with four replicates, totaling 64 experimental units. A cover crop and rice seed inoculation prompted increases in OM and AMF relative to DSE, while the inoculation of rice, regardless of the cover crop treatment, increased the soil’s P content. The combination of maize + Urochloa–I and inoculated rice as the next crop generated increases in its sum of bases (SBs) and cation exchange capacity (CEC). There was a 19% increase in rice grain yields when the seed was inoculated.