Luis Carlos Cirilo Carvalho

Variabilidade espacial e temporal do fósforo, potássio e da produtividade de uma lavoura cafeeira

The Precision Agriculture appears as an important tool to the management of coffee farms where the knowledge of some soil features associated with the coffee production could help specific application of fertilizing with positive environmental and economic results. So the aim of this study was to use precision agriculture and geoestatistics to evaluate the variables phosphorus, potassium and the coffee plant yield, in three different crops, by evaluating the semivariogram and kriging maps and show that these tools are important to the coffee management. This study was conducted on the Brejao farm in Tres Pontas, Minas Gerais, in 2007/2008, 2008/2009 e 2009/2010 crop. As data base were used chemical soil data obtained by sampling in a georreferenced location using a quadricycle with a sampler and a GPS, and the yield data was obtained from manual harvest on the georreferenced location. It was possible to characterize the spatial variability magnitude of the studied attributes, and they presented huge variation on time and space. Adjusts of the best semivariograms enable to produce more accurate maps that contribute to the geostatistics uses on coffee crop.

Métodos de preparo do solo: alterações na rugosidade do solo

Trying to relate the soil tillage methods with some of their effects in Haplustox, it was installed in the municipal district of Uberaba/MG, a research using a completely randomized experimental design in factorial array with five treatments and four replications. The treatments were composed by the soil tillage: chisel plow, rotary tiller, moldboard plow, disk harrow and disk plow. They were appraised: soil mobilized area, elevation area, medium thickness of the mobilized layer, roughness index and the alteration of the roughness of the soil. It was verified that the chisel plow provided larger roughness index of the soil being framed in the conservationist method disaggregating less the soil, collaborating with the smallest soil losses for erosion.

Análise da variabilidade espacial da força de desprendimento dos frutos do cafeeiro sob pivô central

Due to the importance of coffee to the economy of Brazil and the increase of areas even in zone with water deficits during the year, it is necessary to study the factors involved in its production, especially for mechanized and selective harvesting. At this stage coffee farmers find it difficult to determine the appropriate time to start. This research was carried out to evaluating the spatial variation of force detachment of the coffee fruits (green and cherry) under center pivot through geostatistical methods, semivariogram analysis and kriging interpolation, to improve management for harvest mechanical and selective coffee. The test was carried out at Farm Sao Joao Grande, in Presidente Olegario/MG, in a pivot 50.0 ha. The cultivar used was the “Catuai Vermelho IAC 144”, planted in a circular way in December 2000, spaced 4.0 x 0.5 m. The sampling grid was irregular with 100 points georeferenced where each point corresponds to 4 plants. The determination of force detachment was conducted using a digital dynamometer at each sampling point. Within the maturation stages, green fruits presented detachment force greater than the cherry. The semivariogram and kriging allowed to characterize the variability of force detachment between the studied fruits. The kriging maps make it possible to farmers the choice the best place and the right time to start harvest mechanized and selective coffee and consequently, improved final product quality and profits.Due to the importance of coffee to the economy of Brazil and the increase of areas even in zone with water deficits during the year, it is necessary to study the factors involved in its production, especially for mechanized and selective harvesting. At this stage coffee farmers find it difficult to determine the appropriate time to start. This research was carried out to evaluating the spatial variation of force detachment of the coffee fruits (green and cherry) under center pivot through geostatistical methods, semivariogram analysis and kriging interpolation, to improve management for harvest mechanical and selective coffee. The test was carried out at Farm Sao Joao Grande, in Presidente Olegario/MG, in a pivot 50.0 ha. The cultivar used was the “Catuai Vermelho IAC 144”, planted in a circular way in December 2000, spaced 4.0 x 0.5 m. The sampling grid was irregular with 100 points georeferenced where each point corresponds to 4 plants. The determination of force detachment was conducted using a digital dynamometer at each sampling point. Within the maturation stages, green fruits presented detachment force greater than the cherry. The semivariogram and kriging allowed to characterize the variability of force detachment between the studied fruits. The kriging maps make it possible to farmers the choice the best place and the right time to start harvest mechanized and selective coffee and consequently, improved final product quality and profits.

Simple sequence repeat (SSR) markers are effective for identifying pear cultivars and selections

The present study characterized and identified pear cultivars growing in the southern region of Minas Gerais State, Brazil, using microsatellite markers. Nineteen (19) pear cultivars were collected from two sites of Southern Minas Gerais State: Ribeirao Vermelho and Lavras. DNA was extracted from newly formed leaves and amplified using 21 simple sequence repeat (SSR) markers (NH001c, NH002b, NH005b, NH007b, NH008b, NH009b, NH011b, NH013b, NH012a, NH014a, NH015a, NH017a, KA4b, KA5, KA14, KA16, KB16, KU10, BGA35, BGT23b and HGA8b). The data was analyzed by examining unweighted pair group method with arithmetic mean (UPGMA) clustering, principal coordinate analysis, the Shannon index, and the expected heterozygosity for each primer. The markers used were efficient in separating the Asian and European cultivars as well as hybrids. The primer KA16 was noteworthy in distinguishing the species Pyrus communis , Pyrus pyrifolia and Pyrus betulaefolia by its different banding patterns. Grouping by principal coordinates was similar to UPGMA clustering, forming two distinct groups among the Asian and European pears. The Shannon index and the expected heterozygosity had medium values of 0.440 and 0.300, respectively. The pear cultivars from Southern Minas Gerais usually show low productivity, mainly due to the lack of improved strains for less-demanding weather (warmer) conditions. The selection of the most suitable materials would contribute considerably to overcoming this problem, and the markers selected here can be used in separating cultivars - and presumably contribute to the selection of better matrices. Key words: Pyrus sp., Rosaceae, microsatellite, heterozygosity.