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Background and aims: Liming is widely used to alleviate soil acidity worldwide. However, the vast majority of studies with liming are restricted to agricultural systems that incorporate lime into the soil, not considering its effects as surface applications. Although liming effects on soil fertility and crop yield are well understood, there are few studies that elucidate the role of soil improvements in the established crop physiology and the revenue in lime-amended soils, especially when cultivated in regions prone to agroclimatic risks. Here, we address the effects of surface liming, for three growing seasons (2017–2019) subsequent to the lime treatment (2016), on soil fertility, root growth, crop nutrition, photosynthetic pigment concentrations, gas exchange parameters and production costs of maize cultivated in a tropical region on an acidic soil with low water regime. Methods: The treatments consisted of four dolomitic lime doses applied to the soil surface as follows: i) control (untreated soil), ii) half the recommended dose (½ RD), iii) full recommended dose (1 RD) and iv) twice the recommended dose (2 RD). Results: Surface liming increased soil fertility, and higher doses provided better results. Ca2+ and Mg2+ concentrations increased at greater depths under higher lime doses, directly influencing maize root growth. Even under low water availability, also in the driest year of 2018, this liming induced improvement of growing conditions and increased growth was observed'. Maize grown under lime at 2 RD exhibited better nutrition, improved chlorophylls concentration, photosynthetic parameters and water use efficiency. As a result, both shoot growth and grain yield also increased. Net profit in the first growing season was higher in 1 RD, whereas in the two following growing seasons the application of 2 RD resulted in higher revenue. Conclusions: Increased water use efficiency, chlorophyll and photosynthesis were the main physiological traits regulating the growth and yield of maize plants in response to lime supply. Additionally, root development was favoured in the entire soil profile, mainly in deeper layers, after improvements on soil fertility by cascading effects of liming. These results were more prominent in 2RD lime-amended soil, which also resulted in greater net profit over the 3 years studied. [ABSTRACT FROM AUTHOR]

Background and aims: While there is abundant literature on the antagonistic interaction between potassium (K) and magnesium (Mg) during root uptake and transport, there is, however, little published data on the interaction between these nutrients within tissue, especially for sugarcane plants having high demand for K and Mg. This study aimed to investigate the effects of the interactions between K and Mg. Methods: Plants were grown in nutrient solution with increasing K application doses at low and adequate Mg treatments under controlled greenhouse conditions. Leaves, stalks and roots have been analyzed for growth, nutrient concentrations, starch partitioning, and activity of Rubisco. Results: There were significant decreases in Mg concentration in all plant parts by increasing K supply, especially in roots. Leaf symptoms of Mg deficiency appeared not only in low Mg, but also in Mg adequate plants when plants treated with very high K. Magnesium adequate plants contained much higher amount of starch in roots, stalks and young leaves than the low Mg plants when K applications were at low levels. By contrast, there was a high accumulation of starch in the older leaves of the Mg deficient plants. Magnesium deficiency was also associated with significant decreases in Rubisco activity in leaves. Conclusion: Our results show clearly that high K doses interfere significantly with the positive effects of Mg on plant growth, Rubisco activity and starch accumulation in sink organs such as roots and stalks. It is obvious that the imbalance between K and Mg nutrition in sugarcane results in adverse consequences in sugar yield capacity. [ABSTRACT FROM AUTHOR]

Background and aims: The Brachiaria sp. (synonymous with Urochloa) is one of Brazil’s main grass species used in livestock production and has become the focus of breeding genetic programs to enhance its resistance to drought, flooding, and pests, as well as improving its palatability to animals. However, there is a limited understanding of how genetic breeding can affect the soil microbiome and its potential functions. Thus, this study aimed to investigate the impact of four different Brachiaria varieties on the soil prokaryotic and fungal communities, with focus on the N-cycle.We combined molecular techniques, such as quantitative PCR and amplicon sequencing, to target prokaryotic and fungal communities and traditional soil and plant chemical analyses. The treatments were composed of the varieties of B. brizantha cv. Marandu (BM), B. ruziziensis (BR), Brachiaria spp. cv. Ipyporã (BI), B. brizantha cv. BRS Paiaguás (BP) and control without plants.Our findings revealed that all varieties improved soil porosity, P content, organic carbon, and potential functions as Chemoheterotroph, Aerobic-Chemoheterotroph, and Pathotroph-Saprotroph groups. Soil acidity, nutrient availability, and porosity were the main drivers of the microbial communities. The study also identified the ability of each variety to recruit microbial nitrogen-fixers and ammonia-oxidizers.We highlighted that Brachiaria varieties can favor soil microbial communities related to the release of nutrients, resistance to pathogens, and environmental stress. Also, the BI variety showed a higher potential to improve soil quality by increasing soil porosity and potential AMFs. Besides that, all varieties showed some potential to benefit intercropping and crop rotation systems.Methods: The Brachiaria sp. (synonymous with Urochloa) is one of Brazil’s main grass species used in livestock production and has become the focus of breeding genetic programs to enhance its resistance to drought, flooding, and pests, as well as improving its palatability to animals. However, there is a limited understanding of how genetic breeding can affect the soil microbiome and its potential functions. Thus, this study aimed to investigate the impact of four different Brachiaria varieties on the soil prokaryotic and fungal communities, with focus on the N-cycle.We combined molecular techniques, such as quantitative PCR and amplicon sequencing, to target prokaryotic and fungal communities and traditional soil and plant chemical analyses. The treatments were composed of the varieties of B. brizantha cv. Marandu (BM), B. ruziziensis (BR), Brachiaria spp. cv. Ipyporã (BI), B. brizantha cv. BRS Paiaguás (BP) and control without plants.Our findings revealed that all varieties improved soil porosity, P content, organic carbon, and potential functions as Chemoheterotroph, Aerobic-Chemoheterotroph, and Pathotroph-Saprotroph groups. Soil acidity, nutrient availability, and porosity were the main drivers of the microbial communities. The study also identified the ability of each variety to recruit microbial nitrogen-fixers and ammonia-oxidizers.We highlighted that Brachiaria varieties can favor soil microbial communities related to the release of nutrients, resistance to pathogens, and environmental stress. Also, the BI variety showed a higher potential to improve soil quality by increasing soil porosity and potential AMFs. Besides that, all varieties showed some potential to benefit intercropping and crop rotation systems.Results: The Brachiaria sp. (synonymous with Urochloa) is one of Brazil’s main grass species used in livestock production and has become the focus of breeding genetic programs to enhance its resistance to drought, flooding, and pests, as well as improving its palatability to animals. However, there is a limited understanding of how genetic breeding can affect the soil microbiome and its potential functions. Thus, this study aimed to investigate the impact of four different Brachiaria varieties on the soil prokaryotic and fungal communities, with focus on the N-cycle.We combined molecular techniques, such as quantitative PCR and amplicon sequencing, to target prokaryotic and fungal communities and traditional soil and plant chemical analyses. The treatments were composed of the varieties of B. brizantha cv. Marandu (BM), B. ruziziensis (BR), Brachiaria spp. cv. Ipyporã (BI), B. brizantha cv. BRS Paiaguás (BP) and control without plants.Our findings revealed that all varieties improved soil porosity, P content, organic carbon, and potential functions as Chemoheterotroph, Aerobic-Chemoheterotroph, and Pathotroph-Saprotroph groups. Soil acidity, nutrient availability, and porosity were the main drivers of the microbial communities. The study also identified the ability of each variety to recruit microbial nitrogen-fixers and ammonia-oxidizers.We highlighted that Brachiaria varieties can favor soil microbial communities related to the release of nutrients, resistance to pathogens, and environmental stress. Also, the BI variety showed a higher potential to improve soil quality by increasing soil porosity and potential AMFs. Besides that, all varieties showed some potential to benefit intercropping and crop rotation systems.Conclusion: The Brachiaria sp. (synonymous with Urochloa) is one of Brazil’s main grass species used in livestock production and has become the focus of breeding genetic programs to enhance its resistance to drought, flooding, and pests, as well as improving its palatability to animals. However, there is a limited understanding of how genetic breeding can affect the soil microbiome and its potential functions. Thus, this study aimed to investigate the impact of four different Brachiaria varieties on the soil prokaryotic and fungal communities, with focus on the N-cycle.We combined molecular techniques, such as quantitative PCR and amplicon sequencing, to target prokaryotic and fungal communities and traditional soil and plant chemical analyses. The treatments were composed of the varieties of B. brizantha cv. Marandu (BM), B. ruziziensis (BR), Brachiaria spp. cv. Ipyporã (BI), B. brizantha cv. BRS Paiaguás (BP) and control without plants.Our findings revealed that all varieties improved soil porosity, P content, organic carbon, and potential functions as Chemoheterotroph, Aerobic-Chemoheterotroph, and Pathotroph-Saprotroph groups. Soil acidity, nutrient availability, and porosity were the main drivers of the microbial communities. The study also identified the ability of each variety to recruit microbial nitrogen-fixers and ammonia-oxidizers.We highlighted that Brachiaria varieties can favor soil microbial communities related to the release of nutrients, resistance to pathogens, and environmental stress. Also, the BI variety showed a higher potential to improve soil quality by increasing soil porosity and potential AMFs. Besides that, all varieties showed some potential to benefit intercropping and crop rotation systems. [ABSTRACT FROM AUTHOR]