Myriane Stella Scalco

Evolução do crescimento do cafeeiro (Coffea arabica L.) irrigado e não irrigado em duas intensidades de plantio

Com este trabalho, objetivou-se avaliar o crescimento do cafeeiro, cultivar Rubi- MG-1192, submetido a diferentes regimes de irrigacao (sem irrigacao e, com irrigacoes nas tensoes de agua no solo de 20 e 100 kPa) em duas densidades de plantio, 2 500 plantas/ha (4,0 × 1,0 m) e 10 000 plantas/ha (2,0 × 0,5 m). O experimento foi conduzido em uma area experimental do Departamento de Agricultura da Universidade Federal de Lavras/MG. O delineamento experimental foi o de blocos casualizados com quatro repeticoes, utilizando-se o esquema de parcela subdividida, sendo as parcelas compostas pelas duas densidades de plantio e as subparcelas pelos regimes de irrigacao. As caracteristicas fenologicas utilizadas para descrever o crescimento dos cafeeiros foram: altura da planta, diâmetro de copa e numero de ramos plagiotropicos por planta. Foram efetuadas avaliacoes trimestrais, por um periodo de dois anos, oito meses e 20 dias (990 dias). As relacoes entre altura das plantas e epoca de avaliacao e enrtre diâmetro de copa e epoca de avaliacao apresentaram comportamento assintotico. A relacao entre numero de ramos por planta e epoca de avaliacao foi linear. Os tratamentos irrigados apresentaram uma maior altura de plantas, um maior diâmetro de copas e maior numero de ramos plagiotropicos que os nao irrigados. A densidade de plantio nao afetou o diâmetro de copas, mas as plantas mais altas e com maior numero de ramos plagiotropicos foram observadas na maior densidade de plantio.

Adubação nitrogenada e potássica de cafeeiro fertirrigado na fase de formação, em plantio adensado

The objective of this study was to evaluate the most adequate parceling and dose of nitrogen and potassium for the first and second years of coffee shrub (Coffea arabica) formation, under a drip fertigation system, in southern Minas Gerais, Brazil. Two experiments with high plant density (6.666 plants ha -1 ) were carried out simultaneously: in one of them, the fertilization was done in 4 applications yearly, and in the other one, in 12 applications. A randomized block design was used with five treatments and four replicates in both experiments. Treatments consisted of N and K2O doses applied via fertigation: 70, 100, 130, 160 and 190% from the N and K2O recommended doses for the rainfed cropping. A control treatment was carried out in rainfed conditions and fertilized with the standard dose (100%). In the first and second years, in both parceling types, there were no significant differences among doses regarding coffee shrub vegetative growth. Parceling into 12 applications is more suitable for fertilization at both first and second years after planting. Fertigated coffee shrubs at the formation phase have higher growth and demand less nitrogen and potassium fertilization than the ones in rainfed conditions.

Progresso da ferrugem do cafeeiro irrigado em diferentes densidades de plantio pós-poda

Objetivou-se, no presente trabalho, avaliar o efeito de diferentes criterios para manejo da irrigacao em quatro densidades de plantio, sob sistema de gotejamento na incidencia e severidade da ferrugem do cafeeiro e avaliar a influencia do enfolhamento na curva de progresso dessa doenca. Conduziu-se, o experimento, em area experimental da Universidade Federal de Lavras MG, utilizando a cultivar Rubi MG-1192 com seis anos. O delineamento experimental foi em blocos ao acaso com quatro repeticoes. Os tratamentos foram constituidos por quatro parcelas representadas pelas densidades de plantio (convencionais e adensados): 2500 (4,0x1,0 m), 3333 (3,0x1,0 m), 5000 (2,0x1,0 m), 10000 (2,0x0,5 m) plantas ha-1, quatro subparcelas sendo: irrigacoes quando a tensao da agua no solo atingiu valores de 20 e 60kPa; irrigacoes utilizando o manejo do balanco hidrico (calculado atraves do software IRRIPLUS), com turnos de irrigacao fixos de tres dias por semana e uma testemunha sem irrigacao, perfazendo um total de 16 tratamentos. Cada subparcela foi constituida por 10 plantas, sendo consideradas como plantas uteis as seis centrais. Foram avaliadas a incidencia e severidade da ferrugem e a porcentagem de enfolhamento das plantas de cafeeiros. Apos analise estatistica, os dados foram convertidos em area abaixo da curva de progresso da doenca e do crescimento. Verificou-se que os criterios para manejo da irrigacao influenciaram a curva de progresso do crescimento, porem, nao interferiu na curva de progresso da incidencia e da severidade da ferrugem. Os sistemas de plantios adensados favoreceram a incidencia da ferrugem. Mas as densidades de plantio nao interferiram no enfolhamento.

QUALIDADE DE SEMENTES DE CAFEEIRO PRODUZIDAS EM DIFERENTES DENSIDADES DE PLANTIO E REGIMES HÍDRICOS

The water availability during the seed formation of various species is one of the factors that determine their physiological quality. For species such as coffee, seed quality can ensure the production of vigorous and healthy plants, essential to the formation of productive crops. To assess the quality of coffee (Coffea arabica, L.) seeds cultivar Rubi MG-1192, grown under two planting densities (2500 plants ha and 5000 plants ha) and submitted to three drip irrigation systems (control, 20 kPa and 100 kPa) in the course of three harvests (first, second and third years of production) a completely randomized experimental block design was used, in a splitplot with four replications. The seeds were evaluated as to their physical and physiological quality through tests of germination, tetrazolium, bulk electrical conductivity, seedling emergence and percentage of moca and damaged seeds . The most vigorous seeds were obtained within the plant density of 5000 plants ha regardless of the season and the irrigation system. There is an effect of planting density and water availability on seed quality, and this effect is variable depending on climatic conditions, productivity and age of the plant.

Critical ranges for leaf nitrogen and potassium levels in coffee fertigated at the production phase

With the aim of establishing critical ranges for the leaf nitrogen (N) and potassium (K) levels in fertigated coffee crops under production, an experiment was carried out in the experimental area of the Sector for Coffee Cultivation of the Department of Agriculture at the Federal University of Lavras, in Brazil. Treatments consisted of five levels of fertilizer applied through fertigation: 30%, 80%, 130%, 180% and 230% of the recommended amounts of N and K for rainfed coffee grown in Minas Gerais. A randomised block design with four replications was used. Critical ranges for nutrient concentrations in the leaves were established from the results of growth characteristics (plant height and stem diameter), leaf analyses and productivity. The results obtained were: a) nitrogen (g kg-1): 32.39 to 32.40 for January/February; 33.60 to 33.61 for March/April; 27.39 to 27.42 for May/June; 24.23 to 24.24 for July/August; 26.06 to 26.09 for September/October and 26.50 to 26.51 for November/December; b ) potassium (g kg-1): 20.08 to 20.14 for January/February; 17.89 to 17.91 for March/April; 15.93 to 15.96 for May/June; 15.29 to 15.35 for July/August; 16.61 to 16.64 for September/October and 20.58 to 20.64 for November/December.

Water storage in wetted strips under irrigated coffee trees with different criteria of irrigation management

A crescente demanda por recursos hidricos acentua a necessidade de reducao do desperdicio de agua atraves de um manejo mais adequado da irrigacao. No caso particular da cafeicultura irrigada, que nos ultimos anos apresentou crescimento com predominância da irrigacao por gotejamento, o aprimoramento das tecnicas de manejo da irrigacao por gotejamento e uma necessidade. O manejo adequado do gotejamento depende do conhecimento do padrao espacial de distribuicao de umidade no interior da faixa molhada, formada sob as linhas de irrigacao. Neste trabalho, foram utilizadas malhas de 24 tensiometros para determinar o armazenamento de agua no interior de faixas molhadas, formadas sob gotejadores, com vazao de 3,78 L h-1, uniformemente espacados de 40 cm, submetidos a dois criterios distintos de irrigacao (turno fixo e tensao de 60 kPa). Estimativas de armazenamento baseadas em analises unidimensionais, considerando apenas variacoes na profundidade, foram comparadas com estimativas bidimensionais. Os resultados indicam que, com menor turno de irrigacao, a analise unidimensional nao e adequada. Para maior turno de irrigacao, a analise bidimensional e dispensavel, sendo a unidimensional suficiente para o calculo do volume da agua armazenada na faixa molhada.

Leaf miner incidence in coffee plants under different drip irrigation regimes and planting densities

O objetivo deste trabalho foi avaliar o efeito de diferentes regimes de irrigacao por gotejamento e densidades de plantio na incidencia do bicho‑mineiro, Leucoptera coffeella, em cafeeiro arabica, ao longo de um ano. O experimento foi realizado em 2008, em delineamento de blocos ao acaso, em parcelas subdivididas no tempo, com quatro repeticoes. Os tratamentos consistiram de quatro regimes de irrigacao por gotejamento – balanco hidrico climatologico, irrigacoes com base nas tensoes de 20 e 60 kPa, e uma testemunha nao irrigada –, os quais foram distribuidos em tres densidades de plantio: 2.500, 5.000 e 10.000 plantas por hectare. As avaliacoes foram realizadas mensalmente entre janeiro e dezembro de 2008. O maior periodo de ocorrencia da praga foi registrado de agosto a novembro, epoca de baixa umidade relativa do ar antecedida por periodo de estiagem. Cafeeiros irrigados apresentaram incidencia de minas intactas 2,2 vezes menor do que as plantas nao irrigadas. A irrigacao e o aumento da densidade de plantio contribuem para a reducao da incidencia do bicho‑mineiro do cafeeiro.

Water-retaining polymer and seedling type when planting irrigated coffee

The aim of this work was to evaluate the use of a water-retaining polymer on the initial growth of coffee plants for different levels of irrigation and types of seedling. The experiment was set up in pots with a clayey soil, in a greenhouse of the Sector for Coffee Production of the Federal University of Lavras, Brazil. The experiment was arranged in a randomised block design into sub-lots with three replications, giving a total of 48 experimental units. Four levels of irrigation (25%, 50%, 75% and 100% of the available water) were randomly assigned to the lots; the type of seedling (grown in bags or tubes) were randomly assigned to the sub-lots, and the use or not of the water-retaining polymer randomly assigned to the sub-sub-lots. In the treatments with water-retaining polymer, a dilution of 1.5 Kg of polymer to 400 litres of water was used at a dose of 1.5 litres of solution per plant. The following were evaluated at intervals of 60 days during the experiment (360 days from planting): stem diameter, plant height, leaf area, number of leaves and number of plagiotropic branches on the coffee plants. Hydrated water-retaining polymer favoured the growth of coffee plants under an irrigated system. Irrigation resulted in greater plant growth, with the seedlings grown in bags showing more growth than those grown in tubes.

Planos de amostragem no desenvolvimento inicial do cafeeiro sob irrigação

The objective of this study was to evaluate the characteristics of Rubi MG1192 coffee plant and depending on variability of characteristics establish sampling plans for guidence of projects. The treatments consisted of five densities 2,500 (4.0x1.0 m), 3,000 (3.0x1.0 m), 5,000 (2.0x1.0 m), 10,000 (2.0x0.5 m) and 20,000 plants ha-1 (1.0x0.5 m) and five irrigation scheduling criteria (-20, -80, -140 and -200 kPa and SISDA3.5o irrigation scheduler and no irrigation). The planting was accomplished in January, 2001. A completely randomized block design was used with four replications in split-plot. In the main plot were located the plant spacings and in the subplots the irrigation. Sampling plans were established for plant height and diameter of stem and the treetop of coffee plant for various numbers of replications and various numbers of plants per plot. Number of plants and the number of replications were important in the reduction of variability. The coefficient of variation decreased with increased number of plants per plot. The stem diameter showed most variablility as compesed to height and treetop.