Luciano Baião Vieira

Geração de zonas de manejo para cafeicultura empregando-se sensor SPAD e análise foliar

The objective of this work was to define management zones for fertilizer application in coffee crop by using the K-means and the Fuzzy C-Means methods. The data used to define management zones were the chlorophyll index measured by SPAD sensor and the nutritional coffee leaf analysis performed in laboratory. The study was conducted in Jatoba Farm, located in Paula Candido, Minas Gerais state, Brazil. The data was collected in November, 2007 when the coffee fruits were starting their development. The coffee variety was Coffea arabica Catuai, and the total analyzed area was 2.1 ha. The management zones were generated using different set of data: the SPAD values; the N, P and K leaf concentrations; the N and Ca leaf concentrations; the N, Zn and B leaf concentrations; the N, P, K, Ca and S leaf concentrations; and the N, Ca and S leaf concentrations. The management zones generated by using K-means and Fuzzy C-Means did not present difference in management zone delimitation. The management zones defined by using the SPAD values were different from the ones generated by using leaf analysis.

Compactação de um solo de uso florestal submetido ao tráfego de arraste de madeira

The objective of this research was to evaluate compaction of a Red-Yellow Latosol subjected to forestry traffic including two types of skidder: a wheeled-clambunk skidder and a tracked one. This study tries to remedy the lack of information on this subject, considering that mechanized traffic can result in several impacts on the environment. These impacts are related to soil compaction and water resources quality, resulting in reduction of forestry productivity. The soil physical parameters analysed were: soil dry bulk density, total porosity and soil penetrometer resistance. A 2x3x3 factorial statistical design was used, including type of skidder, pattern operation and soil depth, using the Dunnet test at 5% significance level. The statistical analysis included the test of interaction between types of machines and the number of machine travels. Results showed that the loaded wheeled-clambunk skidder traveling once or twice caused effects of compaction on soil up to 15 cm depth. In the same condition, the tracked-skidder traveling twice also produced significant effect on soil compaction. In the 15-50 cm depth, only two travels of the wheeled-clambunk skidder caused soil compaction.

Using an aerial system of remote sensing to detect different nutritional status in Brachiaria decumbens

The aim of this study was to use digital images acquired by cameras attached to a helium balloon to detect variation of the nutritional status in Brachiaria decumbens. The treatments consisted of five doses of nitrogen (0, 50, 100, 150 e 200kg ha-1) with six replications each, evaluated in a completely randomized statistical design. A remote sensing system composed of digital cameras and microcomputers was used for image acquisition, and a helium balloon lifted the cameras to the heights of 15, 20, 25 and 30m. A portable chlorophyll meter and analyses of leaf nitrogen content were used to make comparisons with data obtained by the remote sensing system. Data was acquired in two phases, in different climatic conditions. At the end of each phase, dry matter production was measured. Three vegetation indices were used to evaluate the detection of different nutritional status. The three indices were able to detect the effects of N doses. The indices constructed with the Green spectral band showed to be more efficient.

Deteminação do limite de liquidez em dois tipos de solo, utilizando-se diferentes metodologias

A study concerning the determination of liquid limit was conducted for two types of Latosols. Four methods of determination were used: Casagrande, Casagrande one-point, cone penetrometer and one-point cone penetrometer. The liquid limit was analyzed for both the soils: one originated from the City of Vicosa, MG (with high content of clay particles) and another from Paraopeba, MG (sandy clay loam). The soil from Vicosa presented high values of liquid limit in all methods. Among the used methods, only the one-point Cone Penetrometer method presented a significant difference. There was no significant difference in the determination methods of liquid limit for the other soil. Thus, the content of clay size in the soil has an influence on the methods of determination of the liquid limit.