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Nutritional diagnosis, a technique used to maximize the economic yield of agricultural holdings and to protect the environment, is the focus of this study. Nutrient availability is one of the critical limiting factors in maize grain yield. The study, which aimed to establish and compare the nutritional standards obtained by the Compositional Nutrient Diagnosis (CND) method in maize grown in tropical soils in a semi-arid region, is based on a thorough examination of a database containing information from 198 experimental plots collected between 2011 and 2019 in the semi-arid region of Ceará, Brazil. The evaluation methodology was the multivariate CND calculation method. The mathematical models used to analyze the relationship between the nutrient's CND-r2 index and leaf concentrations revealed coefficients of determination (R2) for nitrogen (N) and magnesium (Mg) of 0.36 and 0.66, respectively. The other values exceeded 70% (R2 ≥ 0.70), while phosphurus (P), calcium (Ca), cupper (Cu), iron (Fe), and manganese (Mn) showed values above 90% (R2 ≥ 0.90). These results not only highlight the high accuracy of these models in studying the interactions between nutrient coefficients and their leaf concentrations but also reassure the reader about the reliability of the research. The study's thoroughness instills confidence in the research's validity. [ABSTRACT FROM AUTHOR]

Conservation systems involving trees enhance the sustainability of tropical soils. However, little is known on the effect of integrated systems with native and exotic trees on soil chemical quality in the eastern Amazon. We aimed to measure changes in soil chemical quality in integrated production systems in Pindaré-Mirim, Maranhão, Brazil. This study was carried out in 2017 and 2018, evaluating (i) perennial pasture; (ii) crop–livestock–forest integration-I (CLFI-I)—eucalyptus rows interspersed with maize + Urochloa brizantha intercropping; (iii) CLFI-II—babassu palm trees (Attalea speciosa Mart.) with maize + Megathyrsus maximus intercropping; and (iv) maize + M. maximus intercropping. Soil chemical attributes at depths of 0.00–0.10 m, 0.10–0.20 m, 0.20–0.30 m, and 0.30–0.50 m, forage productivity, and soil cover were evaluated. CLFI-II promoted the highest soil organic matter concentration in topsoil and highest pH, lowest Al3+ levels, and potential acidity (H+Al) at all soil depths. Soil under pasture showed the highest N, K+, Ca2+ concentrations, sum of bases, and cation exchange capacity. Changes in CLFI-II are associated with the babassu palm's ability to modulate the surrounding environment, giving the species a competitive advantage in anthropic environments. The time of adoption is crucial for improving soil fertility in the Brazilian eastern Amazon. Sustainable production systems in the region must comply with long-term management plans. [ABSTRACT FROM AUTHOR]