ABSTRACT Most soils are excessively acidic, which decreases the productive efficiency of plants. There are several ways to correct soil acidity to make nutrients available to crops. Wood ash is a residue generated by the combustion of vegetal biomass and is used to correct soil acidity for use as a fertilizer. The application of organomineral wood ash to crops is yet another alternative fertilizer that reduces the doses of wood ash and mineral fertilizer. The objective of this study was to evaluate the biomass production and water use efficiency of chrysanthemum cultivated with organic, mineral, and organomineral fertilizers associated with liming. The greenhouse experiment was conducted in a 5 × 2 factorial randomized block design with five fertilization managements (incubated wood ash, non-incubated wood ash, organomineral, mineral fertilization, and control) and two liming values (0 and 100% of the recommendation), with five replicates. Biomass production was significantly affected by fertilization alone and organomineral application resulted in higher biomass production. Incubated ash was more appropriate because resulted in higher yields.

RESUMO A maioria dos solos tem uma acidez excessiva que diminui a eficiência produtiva das plantas. Existem diversas formas de corrigir a acidez do solo e disponibilizar nutrientes para as culturas. A cinza vegetal é um resíduo gerado pela combustão da biomassa vegetal utilizada na correção da acidez do solo e como fertilizante. O organomineral utilizando como matéria prima a cinza vegetal é uma outra alternativa de fertilizante, reduzindo o volume de cinza vegetal e adubo mineral utilizados no campo. Objetivou-se por esta pesquisa avaliar a produção de biomassa e eficiência no uso da água no cultivo de Crisântemo sob adubação orgânica, mineral e organomineral associada a calagem. O experimento foi realizado em casa de vegetação em delineamento de blocos casualizados, com esquema fatorial 5 × 2, sendo cinco manejos de adubações (cinza de madeira incubada, cinza de madeira não incubada, organomineral, adubação mineral e controle) e dois níveis de calagem (0 e 100% da recomendação), com cinco repetições. A produção de biomassa foi significativa somente para adubação de forma isolada e o organomineral demonstrou maior produção de biomassa. Cinza incubada é mais adequada, pois resultou em maiores valores de produção.

RESUMO O objetivo foi avaliar o efeito da dose e do manejo de aplicação de cinzas de madeira nos atributos de qualidade do solo em uma área de Cerrado cultivada com Urochloa brizantha. O experimento foi realizado em blocos casualizados, no esquema em faixas 5 × 2 e quatro repetições. As doses de cinzas foram de 0, 8, 16, 24 e 32 t ha-1, e o manejo de aplicação considerou cinza de madeira incorporada e não incorporada ao solo. Os valores de P, K e pH do solo aumentaram com o aumento das doses de cinza de madeira. A densidade do solo diminuiu 9,66% com as doses de cinzas de madeira de 24 e 32 t ha-1 incorporadas ao solo. Devido ao aumento do pH do solo, dose de cinzas de madeira maior que 16 t ha-1 diminuiu a atividade enzimática. Uma dose de cinza de madeira de 24 t ha-1 resultou em melhores condições para o solo, melhorando sua qualidade e contribuindo para o equilíbrio e a dinâmica entre os atributos químicos, físicos e biológicos do solo, o que levou à redução da densidade e maior disponibilidade de P no solo.

ABSTRACT The objective was to evaluate the effect of wood ash dose and application management on soil quality attributes in a Cerrado area cultivated with Urochloa brizantha. The experiment was carried out in a randomized block design in a 5 × 2 strip-plot scheme and four repetitions. The ash doses were 0, 8, 16, 24, and 32 t ha-1, and the application management considered wood ash that is incorporated and not incorporated into the soil. The P, K, and pH values of the soil increased with an increase in the doses of wood ash. The soil bulk density decreased by 9.66% with the wood ash doses of 24 and 32 t ha-1 incorporated into the soil. Owing to an increase in the soil pH, a wood ash dose of greater than 16 t ha-1 decreased the enzymatic activity. A wood ash dose of 24 t ha-1 resulted in better conditions for the soil, improving its quality and contributing to the balance and dynamics between the chemical, physical, and biological attributes of the soil, which led to the reduced density and greater availability of P in the soil.

RESUMO O Brasil não é autossuficiente na produção de trigo (Triticum aestivum L.) e a expansão do cultivo para o cerrado mato-grossense, em sistema irrigado, constitui alternativa para aumentar a produção desse cereal. Assim, objetivou-se avaliar os efeitos das tensões de água no solo no crescimento e na produção de cultivares de trigo sob Oxisol de Cerrado. Os tratamentos foram arranjados em um esquema fatorial 3 × 5, com três cultivares de trigo (BRS 254, BRS 394 e BRS 264) e cinco tensões de água no solo (5, 15, 25, 35 e 45 kPa), usando um delineamento em blocos casualizados, com quatro repetições. O crescimento e produção do trigo mostraram melhor resposta na tensão de 5 kPa. A cultivar BRS 254 apresentou maior redução na produção de espigas e de grãos por espiga com o incremento das tensões de água no solo. Entre as cultivares, a BRS 264 produziu maior número de grãos por espiga nas tensões de 35 e 45 kPa. As cultivares de trigo BRS 254, BRS 394 e BRS 264 possuem alto requerimento de água. Entretanto, a cultivar BRS 264 apresenta maior crescimento e produção em condições de restrição de água no solo, podendo ser cultivada com um sistema de irrigação acionado com menor frequência, com menor gasto de água e energia.

ABSTRACT Brazil is not self-sufficient for the production of wheat (Triticum aestivum L.), and the expansion of cultivation to the Cerrado in the State of Mato Grosso, in an irrigated system, is an alternative solution to increase wheat production. This study aimed to evaluate the effects of soil water tension on the growth and production of wheat cultivars cultivated in the Cerrado Oxisol. The treatments were arranged in a 3 × 5 factorial scheme, with three wheat cultivars (BRS 254, BRS 394, and BRS 264) and five water tensions in soil (5, 15, 25, 35, and 45 kPa), using a randomized block design with four replications. Wheat growth and production exhibited a better response at a tension of 5 kPa. Cultivar BRS 254 showed the lowest production of spikes and grains per spike with increasing soil water tension. Among the cultivars, BRS 264 produced the highest number of grains per spike at tensions of 35 and 45 kPa. The wheat cultivars BRS 254, BRS 394, and BRS 264 have high water requirements. However, BRS 264 presented greater growth and production under conditions of restricted water in the soil, being able to be cultivated with an irrigation system activated less frequently, with less expenditure of water and energy.

RESUMO A compactação do solo é um problema recorrente na agricultura, levando à redução da produtividade das culturas. Diante disso, a aplicação de resíduo agroindustrial da queima de biomassa vegetal pode melhorar as propriedades químicas e físicas do solo. O objetivo deste trabalho foi avaliar o crescimento do capim paiaguás sob diferentes densidades do solo e doses de cinzas vegetal. O experimento foi conduzido em blocos casualizados, em esquema fatorial 5 × 5, composto por cinco valores de compactação do solo (1,0, 1,2, 1,4, 1,6 e 1,8 Mg m-3) e cinco doses de cinza vegetal (0, 8, 16, 24, 32 g dm-3), com quatro repetições. Densidades do solo acima de 1,2 Mg m-3 reduzem a massa seca do capim paiaguás. A dose de cinza de madeira de 20,42 g dm-3 apresenta o maior valor de massa seca da parte aérea. O crescimento da raiz é maior na dose de cinza de madeira de 16,52 g dm-3.

ABSTRACT Soil compaction is a recurring problem in agriculture that ultimately leads to a reduction in crop productivity. However, the application of agro-industrial residues from the burning of plant biomass can improve the chemical and physical properties of soil. The objective of this study was to evaluate the growth of Paiaguás grass under different soil densities and wood ash doses. The experiment was carried out in a randomized block design, under a 5 × 5 factorial scheme, with five soil compaction values (1.0, 1.2, 1.4, 1.6, and 1.8 Mg m-3) and five doses of wood ash (0, 8, 16, 24, and 32 g dm-3), with four replicates. A soil density greater than 1.2 Mg m-3 reduced the dry mass of Paiaguás grass. The wood ash dose of 20.42 g dm-3 led to the highest shoot dry mass. Root growth was highest at a wood ash dose of 16.52 g dm-3.

RESUMO A adição de cinza da madeira no solo é uma alternativa para a disposição deste resíduo. Porém, seus efeitos nas propriedades físico-hídricas do solo ainda são divergentes. Neste estudo, avaliou-se o efeito da adição de cinzas vegetal na curva característica da água do solo, água gravitacional, capacidade de campo, água total disponível e condutividade hidráulica saturada em um Oxisol e em um Quartzipsamment. O delineamento experimental foi inteiramente casualizado em esquema fatorial 2 × 4, correspondendo a dois solos e quatro doses de cinza vegetal, com três repetições. A cinza vegetal utilizada é proveniente de agroindústria, resultante da queima da madeira de eucalipto. As doses de cinza vegetal foram de 0, 16, 32 e 64 g dm-3, em Oxisol (40% argila, textura Argila) e em Quartzipsamment (6% argila e textura Areia). A água gravitacional, a capacidade de campo e a água total disponível ajustaram-se ao modelo quadrático em função das doses de cinza de madeira. A condutividade hidráulica saturada reduziu linearmente com a aumento das doses de cinza vegetal para ambas as classes de solo. A curva característica do solo aumentou significativamente (p ≤ 0,05) apenas na dose de 64 g dm-3 de cinza vegetal. O aumento do total de água disponível foi mais evidente no Oxisol do que no Quartzipsamment, com incremento de 64 e 31%, respectivamente, na dose máxima de 64 g dm-3 de cinza vegetal.

ABSTRACT The addition of wood ash to soil is an alternative to disposing of this residue. However, the effects of wood ash on soil physical-hydric properties remain divergent. In this study, the effects of added wood ash on the soil water characteristic curve, gravitational water, field capacity, total available water, and saturated hydraulic conductivity were evaluated in Oxisol (40% clay and clay texture) and Quartzipsamment (6% clay and sand texture). The experimental design was completely randomized in a 2 × 4 factorial scheme, where the factors were two soils and four doses of wood ash, with three replicates. The wood ash came from an agribusiness and was the result of burning eucalyptus wood. The wood ash doses were 0, 16, 32, and 64 g dm-3. The gravitational water, field capacity, and total available water were fitted to a quadratic model as a function of the wood ash dose. The saturated hydraulic conductivity decreased linearly with an increase in wood ash dose for both soil classes. The soil water characteristic curve only increased significantly (p ≤ 0.05) with a wood ash dose of 64 g dm-3. The increase in total available water was more evident in Oxisol than that in Quartzipsamment, with increments of 64 and 31%, respectively, at a maximum dose of 64 g dm-3 of wood ash.

RESUMO O objetivo deste estudo foi avaliar o efeito de frequências de irrigação e volumes de substratos sobre a massa de frutos, qualidade de frutos e eficiência do uso da água de melão cantaloupe em ambiente protegido. O estudo foi conduzido na Universidade Federal de Rondonópolis, MT, de fevereiro a agosto de 2021, em delineamento de blocos ao acaso em esquema fatorial 3 × 4 com quatro repetições. Os volumes de substrato utilizados nos vasos plásticos foram de 5, 10 e 15 dm3 e as frequências de irrigação foram uma vez ao dia, duas vezes ao dia, três vezes ao dia e uma vez a cada dois dias. As características avaliadas foram massa de fruto, espessura da polpa, eficiência de uso da água, teor de sólidos solúveis e acidez titulável. As frequências de irrigação de uma e três vezes ao dia apresentaram melhor desempenho para massa de fruto e espessura da polpa. A eficiência do uso da água foi maior para a frequência de três vezes ao dia. Com exceção da acidez titulável, os volumes de substrato de 10 e 15 dm3 apresentaram os maiores desempenhos para todas as variáveis avaliadas. Quanto ao teor de sólidos solúveis os frutos apresentaram níveis que os classificaram como frutos extra, de alta qualidade e indicados para exportação.

ABSTRACT The objective of this study was to evaluate the effect of irrigation frequencies and substrate volumes on fruit mass, fruit quality and water use efficiency of cantaloupe melon in protected environment. The study was conducted at the Federal University of Rondonópolis, MT, Brazil, from February to August 2021, in randomized block design in a 3 × 4 factorial scheme with four replicates. The substrate volumes used in plastic pots were 5, 10 and 15 dm3 and the irrigation frequencies were once a day, twice a day, three times a day and once every other day. The characteristics evaluated were fruit mass, pulp thickness, water use efficiency, soluble solids content, and titratable acidity. The irrigation frequencies of once and three times a day showed the best performance for fruit mass and pulp thickness. The water use efficiency was higher for the frequency of three times a day. With the exception of titratable acidity, the substrate volumes of 10 and 15 dm3 showed the highest performances for all the variables evaluated. As for the soluble solids content, all fruits showed levels that classified them as extra fruits, of high quality and indicated for exportation.

RESUMO A compactação subsuperficial do solo e o estresse nutricional estão entre os principais fatores que limitam a produtividade dos cultivos agrícolas. A utilização de resíduos de origem florestal, como a cinza de madeira, é uma opção viável na recuperação química de solos, podendo proporcionar desenvolvimento radicular vigoroso em solos com compactação subsuperficial. Nesta pesquisa, objetivou-se indicar a dose de cinza vegetal mais adequada com vistas ao manejo eficiente desse resíduo aplicado em culturas rotacionais cultivadas em solos com compactação subsuperficial. Plantas de cártamo (Carthamus tinctorius), uma cultura de rotação com sistema radicular pivotante profundo, foram cultivadas em solo argiloso adubado com diferentes doses de cinza e com níveis de compactação induzida na camada subsuperficial. O experimento foi conduzido em delineamento experimental em blocos casualizados, sob esquema fatorial 4 × 5, composto por quatro doses de cinza vegetal (8,0; 16,0; 24,0 e 32,0 g dm-3) e cinco níveis de densidade do solo (1,0; 1,2; 1,4; 1,6 e 1,8 kg dm-3), com quatro repetições. As variáveis de crescimento da cultura (altura de plantas, número de folhas, diâmetro do caule e índice de clorofila SPAD) foram avaliadas aos 15, 45 e 75 dias após a emergência. Os resultados indicaram que a compactação foi o fator mais limitante ao desenvolvimento vegetativo do cártamo, independentemente da dose de cinza. A interação entre os fatores dose de cinza de madeira e densidade do solo, quando presente, mostrou que a melhor resposta de crescimento ocorreu para a dose de cinza na ordem de 25 g dm-3 para uma densidade de 1,2 kg dm-3.

ABSTRACT Subsurface soil compaction and nutritional stress are among the main factors that limit the yield of crops. Using forest residues, such as wood ash, is a viable option in the chemical recovery of soils and can promote vigorous root development in soils with subsurface compaction. The objective of this study was to indicate the most adequate dose of wood ash for efficient management of this residue applied in rotational crops cultivated in soils with subsurface compaction. Safflower plants (Carthamus tinctorius), a rotational crop with a deep taproot system, were grown in clay soil fertilized with different doses of ash and with induced levels of compaction in the subsurface layer. The experiment was conducted in a randomized block design, under a 4 × 5 factorial scheme, composed of four doses of wood ash (8.0, 16.0, 24.0, and 32.0 g dm-3) and five levels of soil bulk density (1.0, 1.2, 1.4, 1.6, and 1.8 kg dm-3), with four replicates. Crop growth variables (plant height, number of leaves, stem diameter, and SPAD chlorophyll index) were evaluated at 15, 45, and 75 days after emergence. The results indicated that soil compaction was the most limiting factor to the vegetative development of safflower, regardless of the ash dose. The interaction between the wood ash dose and bulk density, when present, showed that the best growth response occurred for ash dose of 25 g dm-3 for a soil bulk density of 1.2 kg dm-3.

ABSTRACT The pre-consolidation pressure is a soil parameter indicating the maximum load that can be supported without irreversible deformation. However, the commercially available equipment for such determination is very expensive, limiting studies on this subject. The objective of this study was to develop a low-cost press model for determining a soil pre-consolidation pressure. The press comprised an electric jack for lifting a soil sample against a fixed piston. A compression cell was built using Technyl®. The stability and smoothness of the applied loads were controlled using springs with different dimensions and strengths. The load and deformation data were obtained using an indicator connected to the load cell and a dial indicator, respectively. The equipment was tested by determining the pre-consolidation pressure in an Oxisol cultivated with cotton and under an area of native Cerrado. The pre-consolidation pressures for a soil water tension of 10 kPa were 50.8 kPa and 61.1 kPa for the soil under the native Cerrado and cotton crop, respectively, and the compressibility indexes were 0.71 and 0.37, respectively. The main advantages of this equipment are its low cost, ease of construction, and simplicity of operation. However, the equipment is non-automatic; thus, the data necessary for the construction of the compression curve must be collected by an operator.

ABSTRACT Soil penetration resistance (PR) assessment is a physical assessment of soil to identify compacted soil layers. Its results are influenced by soil moisture. In this study, a method for correcting PR as a function of soil water content is proposed. The proposed method employs the same function that represents the relationship between PR and soil moisture to calculate the correction that should be applied to the data. The method was evaluated in a Quartzipmment and an Oxisol, at reference moistures of 0.05 to 0.25 kg kg-1 and 0.10 to 0.30 kg kg-1, respectively. In addition, the efficiency was evaluated based on mean absolute error (MAE), bias, and mean absolute percentage error (MAPE). Following correction, the PR data of both soil classes followed the reference PR values (calculated for reference moisture). The largest errors were −0.474 (bias), 0.360 (MAPE), and 0.505 (MAE) for the Oxisol, and 0.112 (bias), 0.616 (MAPE), and 0.286 (MAE) for the Quartzipmment. Furthermore, the best performance occurred at a reference moisture of 0.25 and 0.10 kg kg-1 for Oxisol and Quartzipmment, respectively. Moreover, these moistures were close to the suction pressure of 10 kPa for both soils.

ABSTRACT Penetration resistance can be determined directly in the field or in the laboratory. However, data obtained using the two methods are not directly comparable. Considering soil moisture influences penetration resistance, penetration resistance data obtained using the two methods can be corrected based on common moisture values. To enable comparison of the data, the measured data should be adjusted using mathematical models. Consequently, the objective of the present study was to compare soil penetration resistance values measured in a Red Latosol using a static penetrometer and a bench-top electronic penetrometer. The comparison was carried out using samples collected from different soil layers, based on moisture levels ranging from 0.15 to 0.28 kg kg-1. In addition, the reliability of some mathematical models was compared using bench-penetrometer data. Finally, the Busscher method and a new proposed method for moisture correction were tested. According to the comparison of results between the equipment, it is necessary to correct data using a linear type equation. The Jakobsen & Dexter (1987) model had the optimal performance (R2: 0.89; RMSD: 0.70). The new proposed corrected method was tested using several reference moisture values and it presented minor (< 0.30 RMSD) and stable errors.

RESUMO No estado do Mato Grosso, a cultura do trigo surge como alternativa ao sistema produtivo atual, principalmente em cultivos irrigados, com novas cultivares melhoradas para este ambiente e sistema. Objetivou-se determinar a evapotranspiração da cultura (ETc) do trigo irrigado e os coeficientes duplos de cultivo de cultivares para o Centro-Oeste brasileiro. O experimento foi realizado no campo utilizando 12 lisímetros e minilisímetros de pesagem, preenchidos por monólitos de solo. Foram utilizadas as cultivares de trigo BRS-254 e BRS-394 no primeiro e segundo ano, respectivamente. A evapotranspiração de referência (ETo) foi obtida pela equação de Penman-Monteith e da cultura por diferença de massa nos lisímetros utilizados para determinar o coeficiente de evaporação de água do solo. Foram determinados os coeficientes basais de cultivo e de evaporação de água do solo conforme os estádios de desenvolvimento da cultura nos dois anos de cultivo. Os valores médios de ETc e ETo foram de 3,87, 3,49 mm d-1 e de 4,10 e 3,23 mm d-1, respectivamente, no primeiro e no segundo ciclos de cultivo, com maiores valores de ETc registrados nas fases reprodutivas da cultura, florescimento e enchimento de grãos. Os coeficientes basais de cultivo e os coeficientes de evaporação de água do solo estimados por lisímetros de pesagem preenchidos por monólitos de solo são: Kcb - 0,42, 0,78, 0,94, 0,74 e 0,47 e Ke - 0,72, 0,52, 0,39, 0,58 e 0,13 para a cultivar BRS-254, e Kcb - 0,28, 0,27, 0,65, 0,98 e 0,66 e Ke - 1,04, 0,96, 0,65, 0,34 e 0,51 para a cultivar BRS-394, nos estádios de emergência, perfilhamento, florescimento, maturação e colheita, respectivamente.

ABSTRACT In the state of Mato Grosso, Brazil, wheat is an alternative to the current production system, mainly in irrigated crops, with new cultivars improved for this environment and system. The objective was to determine the evapotranspiration of the irrigated wheat crop and the dual coefficients of cultivars for the Brazilian Midwest. The experiment was conducted in the field using 12 weighing lysimeters and mini-lysimeters, filled by soil monoliths. The wheat cultivars BRS-254 and BRS-394 were used in the first and second years, respectively. Reference evapotranspiration was obtained by the Penman-Monteith equation and crop evapotranspiration by the mass difference in the lysimeters. Basal crop coefficient and soil water evaporation coefficient were determined according to the crop development stages in both years of cultivation. The mean ETc and ETo values were 3.87, 3.49 mm d-1 and 4.10 and 3.23 mm d-1, respectively, in the first and second cultivation cycles, with higher values of ETc recorded in the reproductive stages of the crop, flowering and grain filling. The basal crop coefficients and soil water evaporation coefficients estimated by weighing lysimeters composed of soil monoliths are: Kcb - 0.42, 0.78, 0.94, 0.74 and 0.47 and Ke - 0.72, 0.52, 0.39, 0.58 and 0.13 for the cultivar BRS-254, and Kcb - 0.28, 0.27, 0.65, 0.98 and 0.66 and Ke - 1.04, 0.96, 0.65, 0.34 and 0.51 for the cultivar BRS-394, at the stages of emergence, tillering, flowering, maturation and harvest, respectively.

ABSTRACT Integration of forage grasses with grain crops, such as maize, allows maintaining soil cover. The objective of this study was to evaluate the tensile strength, friability, and stability of soil aggregates in the maize and forage grass intercropping under no-tillage system. The study used a completely randomized block design with seven treatments and three replications. Undisturbed soil samples were collected in two seasons (2015 and 2016) at 0–0.10 m and 0.10–0.20 m soil depth. The following properties of soil aggregates were measured: tensile strength (TS), friability (F), gravimetric moisture (GM), weighted mean diameter (WMD), geometric mean diameter (GMD), and aggregate stability index (ASI). The intercropping of maize with Urochloa ruziziensis presented higher WMD and GMD at 0.10–0.20 m soil depth. Moreover, TS at 0.10–0.20 m soil depth was lower in maize without intercropping. The effects of the intercropping system on soil aggregates were better detected by aggregate stability than by TS or F. The intercropping of maize and U. ruziziensis improved soil aggregation to a higher extent than those systems with other forage grasses.

ABSTRACT The quality of cherry tomato fruits is directly related to the management strategies used in the production system, such as irrigation and fertilization. This study aimed to assess the quality of cherry tomato fruits cultivated under water availability and potassium fertilization. The experiment was carried out in a greenhouse in pots of 12 dm3 of an Oxisol. The experimental design was a randomized block design in a 52 fractional factorial arrangement with five water availabilities in the soil (4, 14, 24, 34, and 44 -kPa), five potassium doses (0, 125, 250, 375, and 500 mg dm−3) and with four blocks. Irrigation was performed with a semi-automated drip irrigation system with soil moisture monitoring by the Diviner 2000® capacitance probe. The assessed variables in fruits were longitudinal and transversal diameter and pulp thickness, fruit shape index, total soluble solids (SS), titratable acidity (TA), the SS/TA ratio, and vitamin C. The data were submitted to statistical analyses at 5% probability error, with analysis of variance by the F-test and polynomial regression. Fruit size presents a reduction as water availability decreased. The total soluble solids have a higher concentration at a potassium dose of 326 mg dm−3. The quality of cherry tomato fruits cultivated in an Oxisol is influenced by water availability and potassium doses.

RESUMO Objetivou-se avaliar a produtividade e o uso da água do tomateiro cereja em ambiente protegido sob disponibilidades hídricas e doses de potássio. O experimento foi conduzido em casa de vegetação utilizando unidades experimentais de 12 dm3 de volume de solo e com delineamento experimental de blocos casualizados em esquema fatorial fracionado 52, com cinco disponibilidades hídricas e cinco doses de potássio, com 13 combinações (4-0; 4-250; 4-500; 14-125; 14-375; 24-0; 24-250; 24-500; 34-125; 34-375; 44-0; 44-250; 44-500) (kPa mg dm-3) e quatro repetições. Foi utilizado o sistema de irrigação por gotejamento com controle da irrigação semiautomatizado. As variáveis analisadas foram massa seca da parte aérea, número de frutos, produtividade, consumo e eficiência no uso da água. A partir dos modelos de regressão constatou-se que a maior produtividade do tomateiro cereja ocorre na tensão de água no solo de 24 kPa e na dose de potássio de 290 mg dm-3. A tensão de água no solo de 44 kPa e a dose de potássio de 290 mg dm-3 possibilitam maior eficiência no uso da água pelo tomateiro cereja. A produtividade e o uso da água do tomateiro cereja são influenciados pelas disponibilidades hídricas do solo e doses de potássio em ambiente protegido.

ABSTRACT The objective of this study was to evaluate the yield and water use of cherry tomatoes under soil water availability and potassium (K) doses in a greenhouse. The experiment was conducted in randomized blocks in a 52 fractional factorial design, corresponding to five levels of water availability and five K doses, with 13 combinations (4-0; 4-250; 4-500; 14-125; 14-375; 24-0; 24-250; 24-500; 34-125; 34-375; 44-0; 44-250; 44-500) (kPa-mg dm-3) and four replicates. A drip irrigation system with semi-automated irrigation control was used. The analyzed variables were shoot dry matter, number of fruits, yield, water consumption and water use efficiency. Highest cherry tomato yield occurs at soil water tension of 24 kPa and K dose of 290 mg dm-3. Soil water tension of 44 kPa and K dose of 290 mg dm-3 allow for higher water use efficiency in cherry tomato. Cherry tomato yield and water use are influenced by soil water availability and K doses in greenhouse.

RESUMO Objetivou-se avaliar a produção e a nutrição mineral do capim piatã em função da adubação nitrogenada e potássica em Latossolo Vermelho coletado no Cerrado. Realizou-se o experimento em casa de vegetação, o delineamento experimental foi inteiramente casualizado em esquema fatorial de 5 x 5 sendo cinco doses de nitrogênio (0, 100, 200, 300 e 400 mg dm-3) e cinco doses de potássio (0, 90, 180, 270 e 360 mg dm-3), com quatro repetições. Realizaram-se três cortes da parte aérea a cada 30 dias. Foram avaliados o índice de clorofila, a massa seca da parte aérea e das raízes, a concentração de nitrogênio e de potássio, nas folhas. A massa seca da parte aérea apresentou interação entre o nitrogênio e o potássio nos três cortes sendo que no segundo e no terceiro apresentou máxima produção nas doses de nitrogênio e potássio, de 254 e 158 mg dm-3 no segundo e de 250 e 306 mg dm-3 no terceiro, respectivamente. As doses de nitrogênio e de potássio apresentaram interação significativa para a massa seca da parte aérea do capim piatã, nos três cortes. As concentrações de nitrogênio e potássio são influenciadas em função da adubação nitrogenada e potássica isolada por fator. A relação de nitrogênio e potássio no capim piatã é de 1:1.

ABSTRACT This study aimed to evaluate the production and mineral nutrition of Piatã grass as a function of nitrogen and potassium fertilization in Oxisol collected in the Cerrado. The experiment was carried out in a greenhouse, the experimental design was completely randomized, in a 5 x 5 factorial scheme, corresponding to five nitrogen doses (0, 100, 200, 300 and 400 mg dm-3 of N) and five potassium doses (0, 90, 180, 270 and 360 mg dm-3 of K2O), with four replicates. Three cuts of the shoots were performed every 30 days. Chlorophyll index, dry mass of shoots and roots, and nitrogen and potassium contents in the leaves were evaluated. The dry mass of shoots showed interaction between nitrogen and potassium in the three cuts; in the second and third cuts, it had maximum production at the nitrogen and potassium doses of 254 and 158 mg dm-3, in the second, and 250 and 306 mg dm-3 in the third, respectively. The nitrogen and potassium contents are influenced as a function of nitrogen and potassium fertilization isolated by factor. The nitrogen and potassium ratio in the Piatã grass crop was around 1:1.