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This study investigates the meteorological variables exerting the most significant influence on the growth and productivity of four tomato hybrids cultivated for industrial processing in the Brazilian Savannah of Goiás State. Data on morphological and meteorological variables were collected in five locations (Hidrolândia, Itaberaí, Palmeiras de Goiás, Piracanjuba, and Silvânia) during the year 2020. Morphological characteristics assessed included plant height, number of branches, and leaf area index (LAI). Meteorological variables considered were average air temperature, global solar irradiance, thermal sum, and soil water availability. Pearson correlations, canonical correlations, and multivariate Stepwise regression were employed to analyze the relationships between morphological and meteorological variables. The study revealed that soil water availability significantly impacts tomato crop development, indicating the need for improved irrigation management. Adequate irrigation management contributed to an 86.1% increase in plant height and a 79.7% boost in leaf area index, while average air temperature influenced a 34% increase in the number of branches. In conclusion, proper irrigation management is crucial for enhancing tomato crop growth and development and optimizing water use.

The agroecological zone model proposed by FAO (ZAE/FAO) is an important tool in agricultural planning and can be used in Jataí, which has been gaining space in the production of sugarcane. The objective of this study was to compare the observed meteorological databases (BDMEP) with the estimated ones (Xavier and NASA POWER), in the estimation of potential productivity (PP) and attainable (PA) of sugarcane and its penalties for management (PMJ) and water deficit (PDF), using the ZAE/FAO model in the municipality of Jataí - GO. To this end, the BDMEP, Xavier and NASA POWER database, 33 years old (1984-2017), were used. Using BDMEP, Xavier and NASA POWER as input in the ZAE model, we observed an average PP of 259±11, 275±10 and 267±11 Mg ha-1 as, respectively. PA reaches 200 Mg ha-1 when using BDMEP in ZAE, with 50% of the crop year with PA above 180 Mg ha-1. There was an average penalty of 114.01±6.9 for management and 85.67±4.08 Mg ha-1 in stem yield. The meteorological variables of Xavier's database can be used in the ZAE model in the prediction of productivity penalty for water deficit and sugarcane management, with 63% and 88% adjustment to BDMEP, respectively. NASA POWER can be used in the simulation of penalty for failures in sugarcane management, with up to 87% approximation of those observed. Both sources when used in the prediction model assist in agricultural planning.

Rainfall is a fundamental component of agricultural production, and knowing its potential and variability can ensure the success of this activity. However, the number of meteorological stations is still small, even in states with agricultural aptitude, such as Goiás. Geoprocessing techniques can be used to overcome this problem. Thus, this study aimed to evaluate the products of the Tropical Rainfall Measuring Mission (TRMM) satellite to describe the annual and monthly rainfall variability in the Goiás state and the Federal District (Brazil). Interpolations were carried out to increase the spatial resolution by means of ordinary kriging and cluster analysis for spatial and temporal distribution. It was observed that the evaluated territory can be classified into three regions with differentiated water regimes up to 500 mm annually, with seasonality of accumulated precipitation from November to March. Even though the regression evaluation showed limitations for a monthly precipitation above 200 mm, the analysis of the TRMM satellite products demonstrated that this tool allows forecasts of provisional normals with a higher spatial resolution than the Brazilian National Institute of Meteorology (INMET) stations network, with known measurement errors for each evaluation period, allowing the data application in forecast models for agricultural planning involving water management.

ABSTRACT The estimate of the potential sugarcane productivity through agroclimatic models aids in the agricultural planning of the crops and the quantification of the yield for a given region. For these estimated values to be considered robust there is a need for validating the performance of such models in different areas and agricultural varieties. Hence, the aim of this study was to validate the Agro-Ecological Zone (AEZ) method with fifteen sugarcane varieties in the region of the Vale do São Patrício, state of Goiás, Brazil. We evaluated the data referring to the cane-plant (one-and-a-half-year sugarcane), as well as the first and second sugarcane ratoons (both with one-year cycles) in an irrigated and dry farming system. The productivities obtained in dry farming were corrected due to the occurrence of a water deficit in the crop. The results indicated that the AEZ method presented productivity estimates more satisfactory for the one-year cultivation cycles (ratoon cycles) for all varieties studied, with the model adjusting best to the CTC15 variety (RMSE = 8.70 t ha-1; MAE = 6.05 t ha-1; d = 0.99).

Resumo A radiação solar é uma variável climatológica amplamente utilizada em estudos climáticos e pode ser mensurada por meio de estações meteorológicas. Devido ao alto custo e difícil manutenção dos equipamentos de mensuração, é possível estimá-la a partir de modelos matemáticos. Assim, o presente estudo objetivou calibrar e validar os parâmetros da equação de ångström-Prescott e de Hargreaves & Samani para realizar a estimativa da radiação solar incidente em Goiânia, Goiás. Dados históricos diários de temperatura máxima (Tmax; °C) e mínima (Tmin; °C), radiação solar incidente (Rs, MJ m-2 dia-1) e duração da insolação (n, h dia-1) da região foram utilizados. Os parâmetros foram calibrados para períodos mensais e sazonais empregando o método dos mínimos quadrados. Os parâmetros estimados foram validados por meio do índice de concordância (d), do coeficiente de correlação (r) e da raiz do erro quadrático médio (RMSE). O parâmetro kRs variou de 0,12 a 0,14 enquanto o parâmetro a variou entre 0,06 e 0,43 e o b de 0,16 a 0,72. As estimativas nos períodos sazonais apresentaram melhor desempenho quando comparadas aos mensais. Os índices obtidos demonstraram boas estimativas para os parâmetros nos períodos sazonais, sendo adequados para estimar a radiação solar no município de Goiânia.

ABSTRACT The answers to when and how much to irrigate orchards can be obtained based on the measurements of plants' transpiration and leaf temperature. This study aims to determine the leaf temperature and sap flow of the pequi tree (Caryocar brasiliense Camb.), both with and without water restriction. Further, the leaf temperature was measured by infrared thermometry and estimated transpiration using the Granier method, where the thermal dissipation probes are inserted into the plant stems. The experiment was conducted in a 120-plant orchard located in Goiânia-GO, Brazil, from which seven of the plants (3 irrigated and 4 non-irrigated; aged 6.6–7.4 years) were evaluated for eight months (October 2015 to May 2016). The soil was characterized as a dystrophic red latosol, and its water content was determined using the EC-5 capacitance sensors. The results denoted that the leaf temperature of the irrigated plants was lower than the median air temperature during summer and the transition period into the dry season, and the non-irrigated plants exhibited shortage of water availability during the dry season. In dryland conditions, the average transpiration was 24.09 L plant−1 day−1 and, when irrigated, became 42.29 L plant−1 day−1.

The irrigation management practices by the producers of industrial tomatoes have been done in an empirical way, which can harm the crop yield and the water resources. Thus, this study aimed to analyze water use, comparing the irrigation management that the producer uses with what should be carried out in the cycle of industrial tomatoes in Goiás. For this purpose, fourteen industrial tomato production areas were monitored during the 2018, 2019, and 2020 harvest. The applied irrigation depths were recorded using rain gauges installed in the cultivation areas. The water demands were estimated from the crop coefficients recommended by Embrapa and by the reference evapotranspiration according to the Penman-Monteith Model, obtained from meteorological data from stations installed in loco. The results showed that water demands ranged from 269.2 to 422.6 mm between 109 and 131 days of the cycle. The diagnosis revealed that there were errors in the irrigation management in all evaluated areas when analyzing the total water applied in the cycle. The average error was 83.3 mm for excess (57% of areas) and 31.1 mm for deficit (43% of areas). The phenological cycle of the crop was divided into four phases. On average, there was excess in two phases, error for the deficit in one phase, and correct irrigation in other. In phase I, there was 35.7% correct irrigation, 50% (35.0 mm) of error for excess, and 14.3% (17.9 mm) of error for the deficit. In phase II, 14.3% of correct irrigation were observed, 85.7% (46.9 mm) of error for excess. In phase III, there was 7.1% of correct irrigation, 14.3% (44.7 mm) of error for excess, and 78.6% (38.2 mm) of error for the deficit. There was 21.4% correct irrigation in phase IV, 42.9% (44.8 mm) of error for excess, and 35.7% (22.1 mm) of error for the deficit.

The objective of this study is to evaluate the growth of pequi trees in function of irrigation and organic fertilization. A total of 96 pequi plants (6-8 years of age), spaced 5 x 5 m, were used in a randomized blocks experiment with six plots and for repetitions. Four treatments were evaluated: IF = Irrigation with fertilization, IWF = Irrigation without fertilization, WIF = Without irrigation with fertilization, and WIWF = Without irrigation and without fertilization, in subdivided plots. The irrigation system was microsprinklers. The volume of water applied was estimated by the evapotranspiration of pequi trees. Cover fertilizations were performed in Nov/2014 using composting material and Yorim, and in Nov/2015 using tanned cattle manure and chicken litter. The growth was monthly evaluated by the height and the stem perimeter, and the canopy was evaluated in a 7.1 years old orchard. Leaf temperature and transpiration were evaluated by sap flow in irrigated and non-irrigated trees. The pequi tree did not respond to treatments in terms of height and stem perimeter. Irrigation provided trees with larger canopy areas. When irrigated, the leaf temperature of pequi trees remained below average air temperatures, independently of dry or rainy periods. Without irrigation, plants presented water stress during the dry season. Under rainy conditions, the mean transpiration of the pequi tree was 24.09 L d-1 per plant. When irrigated, it was on average 42.29 L d-1 per plant.

The African mahogany (Khaya ivorensis A. Chev.) is a tree native from African continent, which has good quality wood and is used in furniture, shipbuilding, doors, among others. This work aimed to verify the Brazilian regions with climate and soil aptitude to the African mahogany. Rainfall, temperature and types of soil were used with variables of reference, from mahogany origin region, especially in the West African coast. From those variables, it was elaborated a selection criterion of regions considered apt, low apt and unapt to the appropriate mahogany growth and development. Brazilian regions that showed range of temperatures between 23°C and 29°C were considered apt, range from 18°C to 23 °C and from 29°C to 35°C were considered low apt, and when the range of temperature was lower than 18°C and higher than 35°C, unapt. To rainfall variable, areas with amount from 830 to 3000 mm year1 were considerate apt, with values less than 830 and higher than 3000 were unapt. Apt regions, to edaphic characteristics, were those that contain the same types of soils found in the origin region of Khaya ivorensis A. Chev. (Ultisol, Oxisol, Neossolo, Quartzarenic Litholic, Insular and Equatorial). From the soil and climate characteristics was determined that 55.62 % of Brazil area was declared apt, 11.66 % apt with slight restrictions, 25.00% apt with mean restriction and 7.71 % restricted.

The rainfall has a direct influence on the agricultural productivity, being indispensable the knowledge of its spatiotemporal behavior in order to establish trends that will assist in the management of water resources, agricultural planning, hydrological monitoring and prevention of natural disasters. Thus, this work aimed to evaluate the accuracy of the TRMM satellite precipitation estimates in relation to the recorded precipitation. For this, the rainfall data from the weather station located in the municipality of Santo Antônio de Goiás - GO were used, being compared to the data of the TRMM satellite, algorithms 3B42 Version 7 and Real Time, in the period from January 1998 to October 2015. The comparison of the TRMM satellite data showed that the ten-day and monthly precipitation records of the algorithm 3B42 V_7 showed correlation values of 0.69 and 0.65, respectively, in the rainy season; in the dry season, the correlations were of 0.80 and 0.73. The ten-day concordance index ranged from 0.68 to 0.98 and the monthly concordance index ranged from 0.83 to 0.99. The algorithm 3B42 Real Time presented lower statistical results when compared to the 3B42 V_7. The satellite precipitation estimates showed both trends of overestimation and underestimation; however, the satellite data can help research in the absence of information on the rainfall in the region.

Irrigation management aimed at optimal production has been based only on the water factor. However, in addition to the water potential of the soil, factors such as soil penetration resistance and soil O2 diffusion rate also affect plant growth and interfere with water absorption, even if moisture is within the available water range. This study aimed at quantifying the least limiting water range and demonstrating its potential in soil and water management in irrigated agriculture. In order to determine the least limiting water range, soil water retention curves and soil resistance to penetration were determined from undisturbed soil samples. The sequential water balance and the reference, crop and real evapotranspiration were determined for a soybean crop season. Soil aeration was the least limiting water range upper limit for soils with bulk density greater than 1.33 Mg m-3, whereas soil resistance to penetration was the lower limit for bulk density higher than 1.43 Mg m-3. The bulk density of the soil studied was 1.35 Mg m-3, indicating 0.37 m3 m-3 of water availability, based on the least limiting water range, which is sufficient to supply the crop evapotranspiration. Irrigation management based on the least limiting water range is more efficient and complete than that based only on available water.

ABSTRACT The aim of this study was to develop and evaluate a low-cost automation system for management of different fertigation regimes in tomato plants (Solanum lycopersicum L.) grown in a protected environment. The system consisted of an irrigation controller coupled to substrate moisture sensors and to a programmable logic controller (PLC). Four water regimes and nutrient supply levels were considered during evaluations. While developing, functional tests were performed to the automation system. Moreover, a cost-benefit analysis for the assembling of the system was carried out. As result, we noted that the automation system was efficient for controlling fertigation. It showed no problems regarding malfunction, still presenting a lower cost if compared to commercial controllers.

Information of jatropha genotypes yield are scarce, but necessary to promote the crop establishment, so it is very important for the commercial planting of this crop. Thus, this study aimed to evaluate the canopy growth and productivity of three jatropha genotypes. The experimental design was a randomized block, with 15 treatments, three replications and five plants per plot. The jatropha genotypes were selected because they have some special characteristics: (CNPAE-107 - small size, CNPAE-133 - productive and CNPAE-169 - seeds without toxicity) obtained in the Germplasm Bank of Embrapa Agroenergy, Brasília, DF, Brazil. The data were collected for five cycles of production. We evaluated: grain yield; height and canopy volume. Treatments differ in all characteristics. Jatropha grain yield has been growing along the first four years of evaluation, however, in the fifth year production was lower when compared to the fourth year. The most productive genotype was CNPAE-133 (2123.8 Kg ha-1 year), followed by CNPAE-107 genotypes (2076.5 Kg ha-1 year) and CNPAE-169 (913 Kg ha-1 year), the highest yields were obtained at 3.7 years.

Water management for irrigation can be defined as a strategy of planning and support systems to save and optimize water resources for human and environmental purposes. Regulated deficit irrigation (RDI) or soil water deficit is a strategy where the amount of water used is kept below the maximum level, and the minor stress that develops has minimal effects on yield. In this irrigation model, the entire root zone is irrigated at less than the maximum crop evapotranspiration, in different phenological phases, without interfering significantly in the physiological behavior of crops. This allows a quantitative and qualitative increase in different crops, and water use efficiency in the agriculture. The present study aimed to identify the effect of regulated deficit irrigation on the qualitative standards of tomato cultivar N-901 for industrialization purposes. Deficit irrigation was carried out during the vegetative growth stage, considering different seedling transplanting periods. The experiment was conducted in a greenhouse at the School of Agronomy of the Federal University of Goias (UFG). The experimental design was a randomized complete block with five replicates, in a 2 x 4 factorial arrangement. The plots were made by combining two periods of irrigation deficit (10 and 20 days after transplanting - DAT) and four soil water tension thresholds (30; 40; 60; and 70 kPa). The results showed that the studied cultivar responded significantly to the soil (substrate) water tension, providing different agronomic development profiles. Water deficit was shown to reduce the total volume of water applied during the cycle, increasing the concentration of soluble solids in the fruits and maintaining titratable acidity in the standards of processing industries, in addition to increasing pulp yield when compared to processing industries. The tensions of 60 and 70 kPa applied at 10 DAT were the ones that most intensified the soluble solids content without significantly affecting the agronomic development of the crop. Keywords: water productivity, deficit irrigation, pulp yield, soluble solids.

Bamboo has a huge potential for several uses; however, there are many species with numerous climatic growth requirements. This makes it difficult to characterize the agro-climatic bamboo demands, in order to define areas suitable for its cultivation. This study aimed to quantify the bamboo agro-climatic requirements, as well as to define areas suitable for growth in the central-north region of the Brazilian Savannah. The agro-climatic requirements were defined from averages of the center of origin of the Bambusa vulgaris species, in southwest Asia. The climatic characterization was based on the daily mean, minimum and maximum air temperature, annual rainfall and water deficit, and consecutive months with a rainfall rate lower than 40 mm. These limits were used to define suitable, marginal and unsuitable regions. The optimal range was between 15.14 ºC and 35.33 ºC for mean air temperature, with a lower limit of 12.07 ºC and a higher limit of 38.83 ºC, respectively, for minimum and maximum air temperature. The annual minimum rainfall required was 775 mm, with a maximum annual water deficit of 1,320 mm, and a maximum of eight consecutive months with rainfall of less than 40 mm. Most of the studied region was classified as suitable (74 % of the total area), followed by marginal due to water deficit (12.9 %), unsuitable (8.9 %) and marginal due to air temperature (4.2 %).

O plantio de mogno africano (Khaya ivorensis A. Chev.) encontra-se em expansão no Brasil para fins de reflorestamento ou produção de madeira nobre. O trabalho objetivou avaliar o crescimento de plantas jovens de mogno africano nas condições micrometeorológicas da região de Goiânia-GO, cultivado sem restrição hídrica. Conduziram-se experimentos em casa-de-vegetação (vasos), durante 141 dias, e em lisímetros, por 160 dias. Em vasos ajustaram-se equações de segundo grau entre as variáveis biométricas e o tempo, exceto para o diâmetro de caule, que ajustou uma linear. Suas taxas de crescimento mostraram tendências oscilatórias no tempo, evidenciando uma rápida dinâmica de distribuição de carboidratos entre os órgãos da planta. Em lisímetros, este ajuste foi exponencial com R2>0,95. O consumo de água médio por planta por dia (CH2O d-1) foi de 2,5 L plt.-1 d-1, e o consumo por metro quadrado de área foliar ke d-1= 0,82 L m-2 d-1. As taxas de crescimento novamente mostraram comportamento oscilatório no tempo, não encontrando relações entre maiores taxas e maior consumo de água. A análise de regressão ajustou equações exponenciais entre as taxas de crescimento, as variáveis micrometeorológicas e CH2O d-1. O ke d-1 foi crescente quando relacionado à radiação solar, déficit de vapor, vento e evapotranspiração de referência, e decrescente em relação à umidade relativa. Conclui-se que, sem restrição hídrica, não existe uma tendência em termos de taxas de crescimento de plantas de mogno africano e as variáveis micrometeorológicas, mas o consumo de água pelas plantas possui forte relação com estas variáveis.

Large farmland areas and the knowledge on the interaction between solar radiation and vegetation canopies have increased the use of data from orbital remote sensors in sugarcane monitoring. However, the constituents of the atmosphere affect the reflectance values obtained by imaging sensors. This study aimed at improving a sugarcane Leaf Area Index (LAI) estimation model, concerning the Normalized Difference Vegetation Index (NDVI) subjected to atmospheric correction. The model generated by the NDVI with atmospheric correction showed the best results (R2 = 0.84; d = 0.95; MAE = 0.44; RMSE = 0.55), in relation to the other models compared. LAI estimation with this model, during the sugarcane plant cycle, reached a maximum of 4.8 at the vegetative growth phase and 2.3 at the end of the maturation phase. Thus, the use of atmospheric correction to estimate the sugarcane LAI is recommended, since this procedure increases the correlations between the LAI estimated by image and by plant parameters.

O Estado de Goiás é o segundo maior produtor de cana-de-açúcar do Brasil. Entretanto, ainda apresenta baixa produtividade, devido principalmente à falta de variedades adaptadas a esta região e ao déficit hídrico típico. Assim, objetivou-se avaliar o desempenho de dezesseis variedades de cana-de-açúcar submetidas à irrigação suplementar no Cerrado. O experimento foi conduzido em Goianésia-GO, em um Latossolo Vermelho-Amarelo Distrófico, de textura argilosa de abril de 2011 a maio de 2012. O delineamento foi em blocos casualizados (Bifatorial 16x5), com 16 tratamentos (variedades): CTC2, CTC4, CTC9, CTC11, CTC15, CTC18, IAC87-3396, IAC91-1099, IACSP94-3046, IACSP94-2094, IACSP94-2101, IACSP95-5000, RB857515, RB92579, RB966928 e SP86-0042; e cinco tempos de avaliação: 113; 145; 174; 203 e 285 dias após o plantio (DAP), com quatro repetições. A irrigação suplementar, por aspersão, correspondeu a uma reposição de 50% da ETc. Os resultados, de cana- planta, apresentaram diferenças significativas entre as variedades avaliadas, destacando-se as variedades CTC9, CTC11, IAC87-3396, IAC91-1099 e SP86-0042, em termos de produtividade e de rendimento industrial. Assim, estas variedades podem ser recomendadas para o cultivo no Cerrado, em regime de irrigação suplementar.

Jatropha stands out in the Brazilian agribusiness scenario as one of the most promising nuts for biodiesel production, although there are few studies on this culture's introduction, management and cultivation techniques. Through the characterization of the state of Goiás' climate based on climate, rainfall and evapotranspiration maps, this work aimed to define areas suitable for the cultivation of Jatropha by designing an agroclimatic zoning system. Rainfall climatic data from 114 stations and air temperature data related to 34 stations were used. The zoning did not show any area that was considered unsuitable for the cultivation of Jatropha in the state, with much of the territory having full culture capability and some marginal regions characterized by water deficit or thermal deficiency. Throughout the state of Goiás, 64.6% of its territory is fit for the cultivation of Jatropha, whereas 35.4% has some marginal conditions for culture development. Of the total of areas defined as marginal to the cultivation of pinion, 28.8% are considered marginal due to water deficits and 6.6% are considered marginal due to thermal deficiency.

The work aimed to evaluate the effect of different methods to overcome dormancy in the germination of Ormosia arborea. The following treatments were used: 72h of water immersion; chemical scarification with 100% sulfuric acid; mechanical scarification + 24h of imbibing and group control, each treatment being carried out with 12h and 0h photoperiods. The seeds undertook luminosity treatments within the period of germination testing in two germination chambers, BOD model. A completely randomized design was used, with four replications. Greater germination percentages were observed in treatments with chemical scarification. There were no germination percentage differences between the 0h and 12h photoperiods in the species under study. One concludes Ormosia arborea seeds present greater germination percentages when undertaking chemical scarification, and luminosity has no influence over the germination of this species.

O objetivo do trabalho foi avaliar o efeito de diferentes métodos de quebra de dormência e da luminosidade na germinação de Ormosia arborea. Foram utilizados oito tratamentos de quebra de dormência: embebição em água por 72 horas; escarificação química com ácido sulfúrico 100% ; escarificação mecânica + embebição por 24 horas e um grupo controle, sendo que, cada um destes tratamentos foi realizado com fotoperíodo de 12 horas e com fotoperíodo de 0 horas. As sementes foram submetidas aos tratamentos de luminosidade durante o período do teste de germinação, em duas câmaras de germinação do tipo B.O.D. Utilizou-se o delineamento inteiramente casualizado, com quatro repetições. Não foram verificadas interações significativas entre os tratamentos. Maiores percentagens de germinação foram observadas nos tratamentos com escarificação química. Tanto as sementes submetidas ao tratamento de fotoperíodo de 12 horas quanto as sementes submetidas a zero horas de fotoperíodo, germinaram; entretanto, as sementes do tratamento sem luz apresentaram velocidade de germinação e percentagem de germinação menor que as sementes colocadas para germinar na presença de fotoperíodo. Concluiu-se que as sementes de Ormosia arborea apresentam maiores percentuais de germinação quando submetidas à escarificação química em condições de luminosidade.

A avaliação da capacidade de raízes de plantas em extrair água do solo é de grande importância na modelagem da taxa de transpiração e, para entender o crescimento e rendimento vegetal e o balanço de água e de solutos no solo. Para testar um modelo de extração radicular macroscópico baseado no processo em escala microscópica, descreveram-se os resultados de um experimento com plantas cujo sistema radicular foi dividido entre camadas de solo com propriedades hidráulicas contrastantes. Um experimento de lisímetro dividido com plantas de sorgo foi realizado em Piracicaba-SP. Quatro lisímetros com dois compartimentos separados fisicamente (split-pot) foram construídos e preenchidos com material de dois tipos de solo de diferentes classes texturais (um solo de textura média - AR e outro de textura argilosa - AG). Durante um mês e meio foi imposto um regime hídrico, alternando a irrigação entre os compartimentos. O teor de água nos compartimentos dos lisímetros foi monitorado com TDR e tensiômetros. O material dos dois solos foi analisado conforme método-padrão quanto às suas propriedades de retenção e condução da água. A densidade radicular foi determinada por pesagem no fim do experimento, tendo ficado em torno de duas vezes maior no solo AR do que no AG. Observou-se que a extração de água ocorreu preferencialmente do compartimento do lisímetro com maior potencial de fluxo matricial. Em certas ocasiões houve transferência de água do lado de maior para o de menor potencial de fluxo matricial, com a liberação da água ao solo pelo sistema radicular (hydraulic lift). Para compensar o efeito da heterogeneidade da distribuição radicular e da atividade radicular, incluiu-se, no modelo, um fator empírico f de correção. O modelo testado descreveu bem 80 % das observações com a utilização de valores de f de 0,01506 e 0,003713, para os solos AR e AG, respectivamente. O modelo simulou a liberação de água ao solo mais frequentemente do que ela ocorreu no experimento. Esse fato pode indicar que a resistência interna do sistema radicular, não contabilizada pelo modelo, pode ter papel importante nas relações hídricas na rizosfera.Evaluating plant root capacity in extrating water from the soil is important for transpiration modeling and to understand crop growth and yield and soil water and nutrient balance. Aiming to test a macroscopic root water extraction model based on the microscopic process description, an experiment was described in which the root system of plants penetrated different soil layers with contrasting hydraulic properties. Four lysimeters containing two physically divided compartments were built and filled with material of two soils with different texture (a medium textured soil - AR and a clayey soil - AG). During a month and a half a water regime was imposed alternating the irrigation among the compartments. The soil water content in the compartments was measured with TDR and tensiometers. Soil hydraulic properties - retention and conductivity - were analyzed by standard methods. Root density was determined by weighing at the end of the experiment, resulting in values twice as high in AR than in AG soil. It was observed that water extraction occurred preferentially from the lysimeter compartments with the highest matric flux potential. Occasionally, water transfer from the compartment with higher matric flux potential to the lower one was observed, releasing water from root to soil (hydraulic lift). To compensate for the effect of heterogeneity of root distribution and root activity and soil-root contact, an empirical factor f was added to the model. Its value was determined by a numerical fitting procedure aiming at the highest correlation between model and observation in the four lysimeters. The model described 80% of the observations satisfactorily by using these f values, which were 0.01506 and 0.003713, respectively, for AR and AG. Model predictions indicated a much more frequent water release from roots to soil than observed in the experiment. This may suggest internal root resistance, not considered by the model, may play an important role in root-water relations.

O objetivo do trabalho foi comparar a eficiência de testes para determinação do potencial fisiológico de lotes de sementes de abóbora. Avaliaram-se seis lotes de sementes, submetidos a testes de germinação e vigor (primeira contagem; velocidade de germinação;germinação à temperatura subótima; envelhecimento acelerado; emergência de plântulas; crescimento e fitomassa seca de plântulas (radícula, hipocótilo e total) e plantas (raiz, caule, raiz e caule, folhas e total). Utilizou-se o delineamento inteiramente casualizado, com quatro repetições; as médias foram comparadas pelo teste de Tukey (p ≤ 0,05). Realizou-se também o teste de correlação de Pearson. Os testes de primeira contagem, velocidade de germinação, envelhecimento acelerado, fitomassa seca de raiz e caule e de folhas de plantas,podem ser utilizados para avaliar potencial fisiológico de sementes de abóbora.This work aimed to determine the efficiency of different tests to access the physiological potential of squash seed lots. Six seed lots were submitted to germination and vigor tests (germination first count; speed of germination; cool germination; accelerated aging; seedling emergence; seedlings growth and dry biomass (root, hypocotyl and total) and plants (root, stem and total length, root, stem,root plus stem, leaves and total). A completely randomized design was used with four replicates. The averages were compared by the Tukey test (p ≤ 0.05). Pearson’s correlation test was also performed. The germination first count, speed of germination, accelerated aging, root plus stem and leaves dry biomass from plants evaluated in the 21st day after sowing can be used to determine the physiological potential of squash seeds.

O trabalho teve por objetivo avaliar a qualidade fisiológica e sanitária de sementes de milheto após a colheita e depois de armazenadas pelo período de 18 meses em condições não-controladas e em câmara fria e seca. Foram avaliados dois lotes de diferentes procedências, os quais foram submetidos aos testes de germinação, vigor e sanidade. Utilizou-se o delineamento inteiramente casualizado e as médias entre lotes e condições de armazenamento comparadas pelo teste de Tukey a 5% de probabilidade. As sementes armazenadas em condições não-controladas apresentaram maior deterioração, evidenciada pela menor germinação e pelo menor vigor. Nas condições de armazenamento em câmara fria e seca, observou-se a manutenção da qualidade fisiológica inicial das sementes. Os resultados referentes à qualidade sanitária mostraram que os dois ambientes de armazenamento foram benéficos para a redução de Penicillium spp. e Aspergillus spp., enquanto a alta incidência de Fusarium spp. no armazenamento em condições não-controladas reduziu o vigor do lote 1. A incidência de Xanthomonas spp. foi alta em todos os períodos avaliados, com diferença entre os lotes, porém isso não se refletiu em redução da qualidade fisiológica das sementes.

A capacidade de campo ou seu equivalente para culturas em vaso, a "capacidade de vaso", é um dado importante para o manejo da irrigação. O objetivo deste trabalho foi determinar, em vasos preenchidos com material de dois solos diferentes (um argiloso e um de textura média), o teor de água e a taxa de perda de água em função do tempo e, a partir dessas determinações, estabelecer valores para a capacidade de vaso a partir de diferentes critérios. Conclui-se que o teor de água final extrapolado da curva observada teta-t é um bom estimador da capacidade de vaso, especialmente para os casos em que a tolerância de perda de água é pequena. Não é recomendável estimar a capacidade de vaso com base em valores "tradicionais" de potencial matricial ou de tempo de drenagem, pois os valores são superestimados em relação aos teores obtidos com base na curva teta-t e correspondem a altas taxas de redução de teor de água.The field capacity, or its equivalent for soils in pots, the "pot capacity", is an important parameter for irrigation management. We aimed to determine both water content and water loss as a function of time in pots filled with material of a clayey and a medium-textured soil. From these data the pot capacity water content was estimated using different criteria. It was concluded that the final water content extrapolated from the observed q-t curve is a good estimator of the pot capacity, especially in situations of low water loss tolerance. An estimation of the pot capacity according to "traditional" pressure heads or drainage times is not recommended, since the obtained values are overestimated, compared to the values obtained by the q-t curve and correspond to high reduction rates of the water content.

Seedlings of high quality are essential for the deployment of homogeneous plants. Thus, was evaluated the formation of seedlings of Jatropha (Jatropha curcas L.) in different substrates fertilized with fertilizer-based lithothamnium. It was used substrates I) mixed of: never cultivated soil, cattle manure and sand in proportions: 3:1:1 volume/volume (v/v); II) commercial substrate Tropstrato®; III) cattle manure and carbonized rice straw in proportions: 1:1 (v/v); IV) birds manure, carbonized rice straw and never cultivated soil in proportions: 1:1:4, and V) fine vermiculite. Lithothamnium fertilizer levels used were 0%, 5% and 10% (v/v), respectively. The experimental design used was randomize blocks with factorial of 5x3 (five different substrates and three different lithothamnium doses) and four replication. Lithothamnium doses and substrates influenced the seedling growth of Jatropha. Seedlings fertilized with the substrates soil with mineral fertilizers (substrates 1); compost with manure and carbonized rice hulls (Substrate 3); soil with hatchery compost (Substrate 4) fertilized with a dose of 6.8% (v/v) lithothamnium showed the best result.

Este trabalho teve como objetivo determinar o período de exposição à baixa temperatura no teste de frio sem solo, para avaliação de diferentes potenciais fisiológicos em lotes de sementes de abóbora. Foram avaliados seis lotes de sementes de abóbora cultivar "Menina Brasileira" (Cucurbita moschata Duch.) produzidas na safra 2003/2004. As sementes foram submetidas a diferentes períodos (três, cinco, sete e nove dias) de exposição à baixa temperatura para condução do teste de frio sem solo, a uma temperatura constante de 10°C. Utilizou-se o delineamento inteiramente casualizado, em que os tratamentos constituíram um fatorial 6x4 (seis lotes e quatro períodos de exposição), com quatro repetições de 50 sementes. As médias foram comparadas pelo teste de Tukey em nível de 5% de probabilidade de erro. Realizou-se também o teste de correlação simples de Pearson .Os resultados permitiram concluir que o período de três dias de exposição à baixa temperatura foi o mais indicado para a condução do teste de frio sem solo em sementes de abóbora.This research was aimed at determining the exposition period at low temperature in the modified cold germination test, to evaluate physiological potential of squash seed lots. Six seed lots of squash, variety Menina Brasileira (Cucurbita moschata Duch.), produced in 2003/2004, were submitted at different exposition times for the development of the cold test. The modified cold gernation test was carried out at 10°C of constant temperature, during exposition time of three, five, seven and nine days. A completely randomized desing was used to the cold test, 0 constituting a factorial 6x4, corresponding to the six seed lots and four exposition time (3, 5, 7, and 9 days), with four repetitions. The averages were compared by the Tukey test, at 5% of probability. The correlation test of Person (r) was used too. For the modified cold germination test, the period of three days was the most indicated to evaluate the physiological potential of squash seeds.

O trabalho foi realizado com objetivo de avaliar a influência de intervalos entre irrigações e densidade de frutos por planta na evolução e partição de fitomassa seca do meloeiro var. Cantalupensis cv. Torreon em hidroponia. Os tratamentos constituíram-se de dois intervalos entre irrigações no período diurno, das 6 às 19 horas, (T15 - 15min de irrigação a intervalos de 15min e T30 – 15min de irrigação a intervalos de 30min) e duas densidades de frutos por planta (D1 - um fruto e D2 - dois frutos). O aumento no intervaloentre irrigações não afetou o padrão de evolução e a partição da fitomassa do meloeiro hidropônico. O incremento de um para dois frutos aumentou a alocação de fotoassimilados para os mesmos, em 58,04 e 46,45% aos 742 e 843 graus-dia, tornando-se vantajoso porproporcionar um acréscimo na produtividade de frutos de 44%.The work were aiming evaluate the influence of intervals between irrigation and fruits densities on evolution and partitioning of dry biomass of muskmelon variety Cantalupensis cultivar Torreon. The treatment tested were constituted in two daily intervals, from 6 to 19 hours, between irrigation (15 min of irrigation in intervals of 15min - T15 and a period of irrigation of 15min and interval of 30min -T30), and two densities of fruit per plant: one fruit (D1) and two fruits (D2). No interaction between treatments for fenometric variable. The increase in intervals between irrigation no affected the growth, partitioning of dry mass and fruits yield muskmelon hidroponic. The increase from one to two fruits per plant allowed more allocation of fotossintates in organs reproductive (fruits) in 58,04 and 46,45% (correspond period from 742 to 843 degree days), being advantageous to provide enlargement yield of fruits of 44%.

O objetivo do trabalho foi comparar a eficiência de testes para determinação do potencial fisiológico de lotes de sementes de abóbora. Avaliaram-se seis lotes de sementes, submetidos a testes de germinação e vigor (primeira contagem; velocidade de germinação; germinação à temperatura subótima; envelhecimento acelerado; emergência de plântulas; crescimento e fitomassa seca de plântulas (radícula, hipocótilo e total) e plantas (raiz, caule, raiz e caule, folhas e total). Utilizou-se o delineamento inteiramente casualizado, com quatro repetições; as médias foram comparadas pelo teste de Tukey (p ≤ 0,05). Realizou-se também o teste de correlação de Pearson. Os testes de primeira contagem, velocidade de germinação, envelhecimento acelerado, fitomassa seca de raiz e caule e de folhas de plantas, podem ser utilizados para avaliar potencial fisiológico de sementes de abóbora.

O trabalho foi realizado com objetivo de avaliar a influência de intervalos entre irrigações e densidade de frutos por planta na evolução e partição de fitomassa seca do meloeiro var. Cantalupensis cv. Torreon em hidroponia. Os tratamentos constituíram-se de dois intervalos entre irrigações no período diurno, das 6 às 19 horas, (T15 - 15min de irrigação a intervalos de 15min e T30 – 15min de irrigação a intervalos de 30min) e duas densidades de frutos por planta (D1 - um fruto e D2 - dois frutos). O aumento no intervalo entre irrigações não afetou o padrão de evolução e a partição da fitomassa do meloeiro hidropônico. O incremento de um para dois frutos aumentou a alocação de fotoassimilados para os mesmos, em 58,04 e 46,45% aos 742 e 843 graus-dia, tornando-se vantajoso por proporcionar um acréscimo na produtividade de frutos de 44%.

ABSTRACT Models that estimate potential and depleted crop yield according to climatic variable enable the crop planning and production quantification for a specific region. Therefore, the objective of this study was to compare methods to sugarcane yield estimates grown in the climatic condition in the central part of Goiás, Brazil. So, Agroecological Zone Method (ZAE) and the model proposed by Scarpari (S) were correlated with real data of sugarcane yield from an experimental area, located in Santo Antônio de Goiás, state of Goiás, Brazil. Data yield refer to the crops of 2008/2009 (sugarcane plant), 2009/2010, 2010/2011 and 2011/2012 (ratoon sugarcane). Yield rates were calculated as a function of atmospheric water demand and water deficit in the area under study. Real and estimated yields were adjusted in function of productivity loss due to cutting stage of sugarcane, using an average reduction in productivity observed in the experimental area and the average reduction in the state of Goiás. The results indicated that the ZAE method, considering the water deficit, displayed good yield estimates for cane-plant (d > 0.90). Water deficit decreased the yield rates (r = -0.8636; α = 0.05) while the thermal sum increased that rate for all evaluated harvests (r > 0.68; α = 0.05).

Abstract The region of study was MATOPIBA, located in the north of Brazilian Savanna biome (Cerrado), encompassing part of north/northeast of Brazil. The region has been gaining prominence in the last years due to the expansion of agricultural over this area. The aims of this study were: to adjust parameters for rainfall intensity-duration-frequency; and to identify the most vulnerable agricultural areas to erosion based on erosivity and erodibility. The rainfall intensity-duration-frequency function were adjusted using series of maximum annual rainfall event from 105 rainfall gauges. Gumbel model was the most efficient to simulate the maximum rainfall intensity, where these data were used to adjusted the rainfall intensity-duration-frequency model based on K, a, b and c parameters. The most rainfall gauges showed intensity between 51 and 80 mm h-1 and 81 and 120 mm h-1, respectively, for return period of 2 and 100 years with rainfall duration of 30 minutes. The higher rainfall intensity was observed mainly in the central-north of the region associated with rainfall systems. The rainfall intensity showed a huge capacity to cause soil erosion based on the erosivity energy, while the moderate erodibility was observed for areas with Ferralsols and Leptosols and low erodibility for areas with Arenosols.

Resumo A chuva (P) e a evapotranspiração potencial (ETP) são variáveis climáticas relevantes para diferentes áreas do conhecimento, tais como: agricultura, manejo de bacias, previsões de tempo e drenagem urbana. O objetivo deste trabalho foi caracterizar os padrões de chuva e de ETP para o município de Goiânia, GO. Foram utilizados dados de 36 anos para chuva e de 21 anos para ETP. A precipitação foi de 1.494,66 mm, com tendência de redução a uma taxa de 3,7 mm ano-1. Observou-se que 99% das precipitações diárias são p ≤ 50 mm dia-1. Registraram-se 292 dias sem chuva e 72 dias chuvosos, com tendência de redução dos dias chuvosos e aumento de dias secos. A ETP foi de 1.380,57 mm, sendo a maior e a menor média registrada no 3° (139,02 mm) e 35° (55,36 mm) quinquídios. Há tendência de aumento na ETP (6,37 mm ano-1). Registrou-se excedente hídrico de 607 mm ano-1 e déficit 471 mm ano-1. ETR/ETP X ¯ ) e 31% ( E T P > X ¯ ), com periodicidades 4,0 (P) e 3,2 (ETP) anos. Observou-se r = 0,68 entre a temperatura média do ar e as taxas de desmatamento.

ABSTRACT African mahogany (Khaya ivorensis A. Chev.) is a tree species that has been increasing in Brazilian commercial planting. However, the lack of water and nutrition are great obstacles for crop production. The aim of this study was to evaluate the growth of young mahogany plants submitted to drip irrigation and topdressing. The experimental design was of randomized blocks, with three repetitions in subdivided plots. Treatments consisted of drippers: 1, 2 and 3plt-1; flows: 2, 4 and 8L h-1, and a treatment without irrigation. For topdressing, subplots levels were, as follows: 1) 17.5 and 25.2; 2) 35.1 and 50.1; 3) 52.5 and 75.0; 4) 70.0 and 100.2; and 5) 87.5 and 125.1 g plant-1 N and K2O, respectively, divided into five bimonthly applications, which started in the 4th month after planting. Plant height, diameter at root collar and at breast height (DBH), and stem height were evaluated. Results showed statistically significant differences (P>0.05) between irrigated and non-irrigated plants. Mean plant height ranged (from 2 to 20 months in field) from 0.33 to 3.25 and 2.67m for irrigated and non-irrigated plants, respectively. Mean stem height ranged from 0.23m to 0.87 and 0.71m for irrigated and non-irrigated plants, respectively. Thus, irrigation with 1 dripper per tree and flow of 2L h-1 was able to supply mahogany water requirements in the first two years in field. Trees have not responded to N and K topdressing at the beginning of the cycle.