Climatic uncertainties have compromised water resources, which influences irrigated agriculture. Irrigation is an important alternative to mitigate the effects of water scarcity. Partial root-zone drying (PRD) is a rational use of irrigation water. This study aimed to evaluate PRD for irrigation management of banana crop, cv BRS Princesa, under semi-arid conditions in Brazil. A field experiment was carried out with five treatments: one control (full irrigation) and four with 50 % reduction of water irrigation depth (WID) and frequencies alternating the side to be irrigated of the plant row of 0, 7, 14 and 21 days. Stomatal conductance, growth, yield and soil water status were evaluated. Results indicated that banana crop cv. BRS Princesa shows shoot physiological regulation for 50 % reduction of soil water and vapor pressure deficit between 1.92 and 2.25 kPa. Decrease in yields of treatments with WID reduction compared to full irrigation is due to the reduction of root uptake rate, which is related to vapor pressure deficit and soil water availability. Partial root-zone drying saves 50 % of irrigation water and increases water use efficiency of banana cv. BRS Princesa crop by 78 %.

The northern semiarid region of Minas Gerais is an important producer of irrigated Prata-Anã banana variety, which is highly susceptible to fusarium wilt. The organic cultivation of resistant varieties may be an phytosanitary alternative, also adding value to fruits. This study aimed to characterize banana varieties produced in organic system based on chemical and physical assessments at post-harvest. Prata-Anã, BRS Platina, Fhia-18, BRS Conquista and BRS Tropical varieties were characterized at the point of harvest (green) and mature (stage six of maturation), by chemical and physical assessments. At the point of harvest, BRS Conquista and BRS Tropical banana varieties had more intense green skin color. ‘BRS Conquista’ presented lower fresh weight, shorter length and diameter than the other varieties. BRS Platinum variety had more fruit fresh mass, length and diameter. Mature Prata-Anã, BRS Platina, Fhia-18, BRS Conquista and BRS Tropical banana varieties showed no difference in soluble solids, pH, titrable acidity and ratio; BRS Platina variety had more intense yellow skin color and lower pulp/skin ratio. Greater dropping resistance occurred in BRS Conquista variety and BRS Tropical was less resistant. Prata-Anã banana variety showed higher firmness. Banana varieties differed more by the physical characteristics (skin color, size, dropping resistance, firmness and pulp/skin ratio) in relation to chemical characteristics.

Knowledge of the cactus pear root distribution system can improve management of the plant by defining the areas of soil best suited to fertilizer application and the installation of soil moisture sensors under irrigation. Thus, the aim of the present study was to assess the root distribution of cactus pear genotypes under different water replacement levels. To that end, a field experiment was conducted in a randomized block design, using genetic material from two cactus pear genotypes (Opuntia fícus-indica Mill. and Nopalea cochenillifera Salm-Dyck) and six water replacement levels based on reference evapotranspiration - ET0 (T1, no irrigation; T2, 15%; T3, 30%; T4, 45%; T5, 60% and T6, 75% of ET0), arranged in split-plot, with irrigation treatments allocated to the plots and the genetic material to the sub-plots, and three replicates. The roots of the cultivars were collected for analysis of root length density (RLD) 390 days after planting. The RDL of very fine roots declines as depth and distance from the plant base increases and total, fine, small and medium RDL rise at higher water replacement levels; 75% of ET0 near the plant base increases RDL; all the root diameter classes are concentrated at a distance of 0-0.20 m from the plant base and depth of 0.10 to 0.25 m; the RDL percentage is higher for the Gigante genotype and Miuda exhibits better root distribution.

The objective of this work was to determine the factors of soil water availability (FSWA) that result in the highest agronomic performance of irrigated forage sorghum, with no changes in the plants' chemical-bromatological composition. The experiment was conducted at the Montes Claros State University, Janaúba campus, MG, Brazil, in a Typic Quartzipsamment (Neossolo Flúvico Psamítico - Embrapa) with 59 mm of soil water storage capacity in the 0.0-0.3 m layer, under drip irrigation. A randomized block design with four replications and a split-plot arrangement was used, consisting of five FSWA (f0.2 = 0.20; f0.35 = 0.35; f0.5 = 0.50; f0.65 = 0.65, and f0.8 = 0.80) in the plots and two simple forage sorghum hybrids (Volumax® and BRS-655) in the split-plots. The evaluations were based on fortnightly measurements of plant height, plant transversal diameter, number of leaves per plant, leaf area index, relative chlorophyll content, stem diameter, panicle length, dry matter yield, water use efficiency, crude protein, mineral matter, acid detergent fiber, neutral detergent fiber, and lignin. The FSWA of 0.20 and 0.35 increased dry matter yield and plant height of the two evaluated sorghum hybrids. The Volumax hybrid presented more crude protein content and acid detergent fiber. The evaluated FSWA did not change the chemical-bromatological composition of the sorghum hybrids.

Dentre os nutrientes exigidos pela bananeira, o K é o que mais influencia na produção desta cultura. Este trabalho teve por objetivos comparar os efeitos de duas fontes de K (cloreto de potássio e sulfato de potássio) sobre a produção, bem como estimar as doses de K para obter a máxima eficiência física (MEF) e econômica (MEE) e determinar o nível crítico de K na folha da bananeira 'Prata anã' (AAB) irrigada, cultivada na região semiárida do norte de Minas Gerais, Brasil. O experimento foi realizado em Latossolo Vermelho-Amarelo (LVA), textura média. Os tratamentos foram originados do fatorial (4 x 2), sendo quatro doses de K (0, 400, 800 e 1200 kg /ha ano de K2O) e duas fontes de K (KCl e K2SO4), gerando oito tratamentos, que foram distribuídos em blocos ao acaso, com quatro repetições. Não houve diferenças entre os efeitos do KCl e K2SO4 sobre a produção da bananeira. A análise econômica demonstrou que o KCl apresentou maior viabilidade para ser utilizado como fonte de K. As doses estimadas para a MEF nos 2º e 3º ciclos de produção, utilizando-se o KCl, foram de 827 e 835 kg ha-1 ano-1 de K2O, respectivamente. Já para a MEE, as doses foram de 157 e 670 kg/ha ano de K2O, respectivamente. Os níveis críticos foliares de K, obtidos nos 2º e 3º ciclos de produção, foram de 2,85 dag kg-1 para a MEF e, para a MEE, de 2,41 e 2,80 dag kg-1, respectivamente.

O objetivo deste trabalho foi avaliar o crescimento de plantas de café arábica (Coffea arabica) enxertadas sobre café robusta (C. canephora), submetidas a diferentes níveis de reposição de água. O experimento foi realizado em Lavras, MG, em delineamento experimental de blocos ao acaso, em arranjo fatorial 2x2x5, com quatro repetições. Foram feitas avaliações em: duas cultivares de C. arabica - Catuaí IAC-99 e Topázio MG-1190 -, dois tipos de plantas - pé-franco e enxertadas sobre C. canephora 'Apoatã IAC-2258' - e cinco níveis de reposição de água - testemunha sem irrigação e quatro coeficientes de cultura, nos valores 0,2, 0,3, 0,4 e 0,5, do plantio até 24 meses, e 0,4, 0,6, 0,8 e 1,0, de 24 a 29 meses -. Utilizou-se turno de rega fixo, com irrigações às terças e às sextas-feiras. Foram avaliados: altura de plantas, diâmetro de copa e diâmetro de caule. Cafeeiros enxertados têm menor crescimento em comparação aos de pé-franco, no período de implantação da lavoura. A substituição do sistema radicular de C. arabica por C. canephora não altera a resposta das plantas à irrigação.