Efficient irrigation management is crucial for optimizing crop development while minimizing resource use. This study aimed to assess the spatial variability of water distribution under conventional sprinkler irrigation, alongside soil moisture and infiltration dynamics, using multispectral sensors onboard Remotely Piloted Aircraft (RPAs). The experiment was conducted over a 466.2 m² area equipped with 65 georeferenced collectors spaced at 3 m intervals. Soil data were collected through volumetric rings (0–5 cm), auger sampling (30–40 cm), and 65 measurements of penetration resistance down to 60 cm. Four RPA flights were performed at 20 min intervals post-irrigation to generate NDVI and NDWI indices. NDWI values decreased from 0.03 to −0.02, indicating surface moisture reduction due to infiltration and evaporation, corroborated by gravimetric moisture decline from 0.194 g/g to 0.191 g/g. Penetration resistance exceeded 2400 kPa at 30 cm depth, while bulk density ranged from 1.30 to 1.50 g/cm³. Geostatistical methods, including Inverse Distance Weighting and Ordinary Kriging, revealed non-uniform water distribution and subsurface compaction zones. The integration of spectral indices within situ measurements proved effective in characterizing irrigation system performance, offering a robust approach for calibration and precision water management.

A população de plantas é um fator que está sob controle do produtor e interfere de forma significativa na produtividade de grãos em qualquer cultura. Determinar a população ideal que proporciona o máximo desempenho de cada cultivar se torna importante para se obter uma produção ótima de grãos. O objetivo desse trabalho foi avaliar o desempenho agronômico de duas cultivares de feijão-caupi de porte semiereto e semiprostrado em diferentes populações. O experimento foi conduzido em esquema fatorial 2x4 (cultivares e populações de plantas). O delineamento foi em blocos casualizados, com quatro repetições. Foram avaliadas quatro populações de plantas: 120, 160, 200 e 240 mil plantas ha-1. As características avaliadas foram: altura de plantas, comprimento de vagens, número de grãos por vagem, produtividade de grãos e massa seca da parte aérea. As populações de plantas avaliadas influenciaram apenas na produtividade de grãos. A cultivar BRS Marataoã, de porte semiprostrado, apresentou maior número de grãos por vagem, altura de plantas e produtividade de grãos. A população que proporciona maior produtividade de grãos é próxima de 160 mil plantas ha-1.

Accurate precipitation estimation is essential for water resource management, especially in tropical regions where the spatial and temporal variability of rainfall presents significant challenges. In areas with limited terrestrial station coverage, satellite-based products such as the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) have become particularly valuable. This study compares CHIRPS data with surface station records in the Paracatu River Basin in the Brazilian Cerrado from 2010 to 2023, employing a “point-to-pixel” approach. Among the statistical analyses, we have used metrics commonly applied in precipitation studies, such as Pearson’s correlation coefficient (CC), relative bias (BIAS), coefficient of determination (R²), and root mean square error (RMSE). Monthly coefficients of determination (R²) ranged from 0.77 to 0.89, reflecting CHIRPS’ capability to capture rainfall patterns on this scale. However, its accuracy decreased when estimating total annual precipitation, highlighting some limitations. Despite these challenges, CHIRPS is a valuable tool for supplementing surface data on a monthly basis, although discrepancies are more pronounced during periods of intense rainfall and in annual aggregates. Future research should investigate the integration of additional remote sensing products and assess how changing climate conditions affect precipitation estimates.

Drought stress is a major factor limiting sorghum yield, especially in regions with irregular rainfall. This study investigated the morphophysiological and growth responses of grain sorghum hybrids to drought stress, comparing the effects at pre- and post-flowering stages. Twenty hybrids were evaluated under well-watered conditions and under drought imposed at the pre- and post-flowering stages, using a randomized complete block design, with three replications. The evaluated traits were plant height, leaf area index, shoot dry weight, and chlorophyll index. Growth parameters, including absolute growth rate, relative growth rate, leaf area ratio, leaf weight ratio, specific leaf area, and net assimilation rate, were also determined. The pre-flowering drought caused the greatest reductions in plant height, leaf area index, and dry weight accumulation, whereas the post-flowering drought had the greatest effect on leaf area ratio, chlorophyll index, and net assimilation rate. The grain yield under pre-flowering water stress was approximately 4,000 kg ha-1, significantly higher than the 2,500 kg ha-1 observed under post- flowering stress, suggesting a greater capacity for recovery and grain production when water availability is restored before the reproductive stage.