Manoel Alves de Faria

Crescimento e produtividade do girassol cultivado na entressafra com diferentes lâminas de água

In this study the experimental data obtained in the period from March to July of 2004 in the Federal University of Lavras (UFLA) were used, with the objective of evaluating the productivity of grains and of oil and other agronomic characteristics of two sunflower genotypes (Helianthus annuus L.) (H250 and H251), irrigated in the late summer growth period. The experiment was carried out with four treatments of drip irrigation water depths of 0 (L0), 75 (L1), 100 (L2) and 130% (L3) of the evapotranspiration estimated for the crop, corresponding, respectively, to the water depths of 117.20, 350.84, 428.70 and 522.14 mm. The productivity of grains and of oil, the height of sunflower plants and the capitulum diameter increased with water depth. The used cultivars presented differences of oil productivity, weight of 1000 achenes and plants height. There was an technical efficiency in production, even without irrigation, with average productivity of 1924.27 kg ha-1 and, in irrigated condition, there was increase of this productivity reaching the 2863.12 kg ha-1 for water depth of 522.14 mm (130% ETc) applied in the crop cycle. The analyzed genotypes can be used during the summer cycle, in Lavras, as an option in the crop rotation.

Variabilidade espacial de atributos físicos do solo associados ao uso e ocupação da paisagem

This work aimed to diagnose current agricultural soil use as well as its implications for the spatial variability of soil bulk density (Ds), organic matter (OM), particle-size distribution and water dispersible clay (WDC), in Ribeirao Marcela watershed, belonging to Alto Rio Grande region, using geostatistics tools, in order to observe occurrence patterns of these attributes in the landscape. Disturbed and undisturbed soil samples were collected in 0-0.15 m layer, in a grid of 240 x 240 m (macro-scale) and 60 x 60 m (micro-scale), resulting in 165 samples. Current soil use is not in accordance to soil class agricultural suitability. Soil bulk density presented values between 1.05 and 1.15 g cm-3, this range being above characteristic values for Oxisol (close to 0.95 g cm-3), with the highest values found in lands under pasture. Organic matter values ranges from 1.5 to 4.5 dag kg-1, detecting higher concentrations in lands under eucalyptus, cerrado and wetlands. Particle-size distribution presented behavior following the drainage pathways and WDC presented low values in the entire watershed. Kriging maps were shown to be important tools for the understanding of spatial variability of physical soil attributes in the watershed, indicating critical management areas.

Response of Jatropha curcas crop to irrigation and potassium fertilization levels.

Jatropha curcas crop is raising attention as an alternative crop for biodiesel production. Despite the irrigation and mineral fertilization to promote increase of Jatropha curcas yield, few studies have been conducted on this issue. The purpose of this work was to evaluate the growth and productivity of Jatropha curcas, in response to irrigation management and potassium fertilization doses. The field experiment was carried out at the Federal University of Lavras in the southern part of the State of Minas Gerais. Four different irrigation depths, corresponding to different fractions (0, 40, 80, 120%) of the Class A pan evaporation (ECA), and four potassium doses (30, 60, 90 and 120 kg ha-1 of K2O) were used as treatments. To evaluate the growth and yield of Jatropha curcas seeds the data corresponding to first and second year of cultivation was used. The results showed that plants irrigated showed better productivity and initial growth, while potassium fertilization levels did not show significant effect.

Produtividade e rendimento de sementes de pinhão-manso submetido à irrigação e adubação com OMM-Tech

The purpose of this study was to evaluate the effects of irrigation and application of Organo-Minerals-Marine+Biotech (OMM-Tech) in yield and production efficiency of the Jatropha curcas. The experiment was conducted in an experimental area located in Federal University of Lavras, Brazil. A randomized block design with subdivided parcels and three replications was used. The parcels were submitted to different OMM-Tech fertilizer application methods: T1= control (no OMM-Tech); T2 = soil application (120 kg ha-1 of OMM-Tech in a powder form); T3 = leaf application (OMM-Tech in a liquid form with a 5% concentration); T4 = soil + leaf application (60 kg ha-1 of OMM-Tech as powder + OMM-Tech in liquid form with a 2.5% concentration). The sub-plots received two different water management treatments: with and without irrigation. A drip irrigation system with emitters spaced by 0.50 m was used. It was evaluated productivity and production efficiency of seeds in the first yield year. The plants irrigated and fertilized with 120 kg ha-1 of OMM-Tech solid in soil showed better productivity.

Métodos de ajuste e modelos de semivariograma aplicados ao estudo da variabilidade espacial de atributos físico-hídricos do solo

The spatial variability and spatial dependence structure of physical water soil attributes (total porosity - VTP, saturated hydraulic conductivity - k0, drainable porosity - DP and soil moisture at field capacity - qcc) was evaluated for an Oxisol representative of Ribeirao Marcela watershed, in the Alto Rio Grande domain. Spherical and exponential semi-variograms were fitted by the weighted minimum square (WMS) and maximum likelihood (ML) methodologies. Undisturbed and disturbed physical water samples were collected from the 0-0.15 m layer for characterization, in grids of 240 x 240 m and 60 x 60 m, totaling 165 sampling points. VTP and qcc presented low variability, with coefficients of variation (CV) of 7.54 % and 10.22 %, respectively. The mean DP variability was intermediate, with CV of 43.2 %, and was high for k0 with a CV of 88.3 %. All attributes presented spatial dependence structure, which was strong for VTP, qcc and k0, with a dependence degree (DD), respectively, of 81.82, 75.31 and 82.61 %. The spatial dependence structure of DP was moderate with a DD of 54.66 %. The domains of VTP, qcc and DP were around 1.000 m and for k0 it was about 77.46 m. The results of both methodologies were similar, so that both are recommendable for the fitting of semi-variograms to physical water soil attributes. Based on cross-validation, spherical semi-variograms can be indicated for VTP, qcc and k0, with a Mean Square Error (MSE) close to 0.00161, 0.2795 and 0.00155, respectively, and the exponential model recommended for DP, with MSE of 0.004070.

Resposta do cafeeiro cv. Topázio MG-1190 submetido a diferentes épocas de irrigação

This study was conducted in an experimental coffee (Topazio MG-1190) plantation at the Universidade Federal de Lavras, located in Lavras, in the state of Minas Gerais, Brazil. The 28-month-old experimental coffee plantation was established with a narrow spacing between plants (1.8 x 0.70 m) and is drip irrigated. In July of 1998, the installation of 4 L h-1 discharge emitters spaced at 0.40 m formed a wetted stripe along plant lines. The treatments were six different irrigation seasons: T0 not irrigation, T1 (irrigation from April to July), T2 (irrigation from April to June), T3 (irrigation from September to November), T4 (irrigation from May to June), and T5 (irrigation from August to October). During the irrigation season an amount of water corresponding to 83% of the evaporation of a Class A pan was applied every Tuesday and Friday. The experimental design was a randomized complete block with four replications. The results were submitted to analysis of variance and to a Scott-Knott test of means. Vegetative growth, yield and yield quality from the 99/00 crop season were analyzed. Among all parameters used to quantify vegetative growth only stem diameter and plant height showed response to the treatments. The treatment T3, in contrast to T5, anticipated maturation, presenting more than 70% of grains at the raisin-grain and dry-grain stage. With respect to crop yield, neither the amount produced nor the percentage of coffee beans that fell on the soil before harvest showed significant differences between treatments. Both chemical and sensorial qualities were adequate, fulfilling the requirements for exportation.

Spatial-temporal analysis of water requirements of coffee crop in Minas Gerais State, Brazil

Scientific investigations about crop water requirements are of fundamental importance to the irrigation process. The main objective of this paper is to analyze and to map water requirements of coffee crop in Minas Gerais State, Brazil. Potential evapotranspiration values (ET0) were estimated by the Penman-Monteith-FAO method, using daily data sets available for 42 National Meteorology Institute (INMET) stations for a period of 17 years. The crop coefficient values (kc) considered were extracted from literature. The results were analyzed by means of geostatistical tools. The theoretical semi-variograms were fitted by the Maximum Likelihood method, considering spherical, exponential and Gaussian models. The maps were created using the ordinary kriging method. In a general way, the results have showed that the coffee crop evapotranspiration (ETc) presents high variability in Minas Gerais State. The largest variations, both spatial and temporal, have been observed in the northern part of the State. January and June, respectively, presented the highest and the smallest water requirements of coffee crop. Based on this, we can conclude that due to the coffee crop evapotranspiration (ETc) data distinction in different regions of Minas Gerais, a good estimate of the ETc values for each locality will bring many benefits to the coffee growers regarding irrigation scheduling.

Viabilidade técnica e econômica do cultivo de safrinha do girassol irrigado na região de Lavras, MG

Por meio deste estudo de viabilidade tecnica-economica utilizou-se os dados experimentais obtidos na Universidade Federal de Lavras (UFLA), no periodo de marco a julho de 2004, com o objetivo de avaliar as eficiencias tecnicas e economicas do cultivo do girassol na regiao de Lavras, MG, no periodo de safrinha, em duas situacoes distintas, sendo uma na condicao que o produtor nao possui o sistema de irrigacao (nao irrigante) e outra que o produtor e irrigante e quer decidir de que forma deve conduzir a lavoura. Os dados utilizados foram provenientes de experimentos conduzidos com os tratamentos de lâminas de agua referentes a reposicao pela irrigacao, de 75, 100 e 130% da evapotranspiracao estimada para a cultura, num intervalo de dois dias (turno de rega fixo) e a testemunha que nao era irrigada, correspondendo, respectivamente, as lâminas de agua recebida de 350,84 mm, 428,70, 522,14 e 117,20 mm. Os dados usados na analise foram a produtividade do girassol obtida nos experimentos e os custos da lavoura nas duas condicoes anteriormente citadas. Para o caso da lavoura irrigada, considerou-se como sistema de irrigacao o pivo central e a estimativa dos custos da lavoura foi baseada na teoria dos custos de producao. Os resultados mostraram que houve eficiencia tecnica, uma vez que a produtividade media para a situacao nao irrigada (117,2 mm de chuva) foi de 1924,27 kg ha-1 e para a situacao de irrigacao de 2293,15 kg ha-1, 2564,26 kg ha-1 e 2863,12 kg ha-1, respectivamente para as lâminas de agua correspondentes de 350,84, 428,70 e 522,14 mm. Na situacao economica analisada, cujo preco da saca de girassol considerado foi de R

Manejo e viabilidade econômica da irrigação por gotejamento na cultura do cafeeiro acaiá considerando seis safras

31,80 (junho/2004), recomenda-se para o produtor irrigante a aplicacao da lâmina de 522,14 mm de agua ao longo do ciclo, mas a persistir tal situacao, o produtor podera entrar em um processo de descapitalizacao, nao repondo parte do capital fixo, tendo que optar por outra alternativa de mercado.

Sistema computacional para a determinação da lâmina ótima econômica em irrigação pressurizada

Este trabalho teve como objetivo estudar tecnica e economicamente o efeito da irrigacao por gotejamento na producao do cafeeiro (Coffea arabica L.) Acaia MG-1474. O delineamento experimental utilizado foi o de blocos casualizados, com cinco tratamentos e quatro repeticoes. Os tratamentos foram: L0 = sem irrigacao; L40 = 40%; L60 = 60%; L80 = 80% e L100 = 100% da Evaporacao do Tanque Classe A (ECA). Para realizar a analise economica, utilizou-se dos dados de producao acumulada das seis primeiras safras: 1999, 2000, 2001, 2002, 2003 e 2004. A analise dos custos da lavoura irrigada foi baseada na teoria dos custos de producao. A produtividade media dos tratamentos foi de 52,88; 66,99; 70,00; 71,93 e 79,50 sacas por hectare, para L0, L40, L60, L80 e L100, respectivamente. Considerando o preco da saca de cafe a R