Jener Fernando Leite de Moraes

Classificação climática de Köppen e de Thornthwaite e sua aplicabilidade na determinação de zonas agroclimáticas para o estado de são Paulo

Climate can be understood as the mean atmospheric condition for a certain region. It affects directly most of the human activities, in special agriculture since it defines final yield levels, conditioned mainly by the regional water availability. However, the climatic classifications systems (SCC) are not often used for agricultural studies because usually their scales are considered very wide. Therefore monthly mean values of maximum and minimum air temperature of 27 termometric stations and 427 pluviometric stations of State of Sao Paulo were utilized to update and improve the mapping of two SCC, Koppen modified and Thornthwaite, besides to evaluate their applicability for agroclimatic zonning for the State of Sao Paulo. The use of 427 localities resulted in amore accurate mapping of the State by both climatic classifications. Their applicability on agroclimatical studies was evaluated through the separation capacity of the climate types by two systems, in relation to the meteorological elements and components of normal water balance. It was used data dispersion analysis, Tukey´s test and cluster analysis with independent data. The Koppen SCC showed to be efficient only for macroscale and low capacity of climate types separation in relation to meteorological elements (air temperature, rain) and data resulting from water balance (evapotranspiration, deficit and surplus). As a result this SCC should not be used in agrometeorological studies. On the other hand, Thornthwaite SCC efficiently separates the climate types in toposcale or mesoscale in view of the fact that it can efficiently resume generated informations by normal water balance, indicating ability to determine agroclimatical zones. Discussions were also made about sowing dates and final quality of agricultural products related to the two SCC considered question.

Forest- and pasture-derived carbon contributions to carbon stocks and microbial respiration of tropical pasture soils

The clearing of tropical forest for pasture leads to important changes in soil organic carbon (C) stocks and cycling patterns. We used the naturally occurring distribution of13C in soil organic matter (SOM) to examine the roles of forest- and pasture-derived organic matter in the carbon balance in the soils of 3- to 81-year-old pastures created following deforestation in the western Brazilian Amazon Basin state of Rondônia. Different δ13C values of C3 forest-derived C (-28‰) and C4 pasture-derived C (-13‰) allowed determination of the origin of total soil C and soil respiration. The δ13C of total soil increased steadily across ecosystems from -27.8‰ in the forest to -15.8‰ in the 81-year-old pasture and indicated a replacement of forest-derived C with pasture-derived C. The δ13C of respired CO2 increased more rapidly from -26.5‰ in the forest to -17‰ in the 3- to 13-year-old pastures and indicated a faster shift in the origin of more labile SOM. In 3-year-old pasture, soil C derived from pasture grasses made up 69% of respired C but only 17% of total soil C in the top 10 cm. Soils of pastures 5 years old and older had higher total C stocks to 30 cm than the original forest. This occurred because pasture-derived C in soil organic matter increased more rapidly than forest-derived C was lost. The increase of pasture-derived C in soils of young pastures suggests that C inputs derived from pasture grasses play a critical role in development of soil C stocks in addition to fueling microbial respiration. Management practices that promote high grass production will likely result in greater inputs of grass-derived C to pasture soils and will be important for maintaining tropical pasture soil C stocks.

Indicadores ambientais para áreas de preservação permanente

Apesar da conscientizacao pelas questoes ambientais, existe uma crescente pressao sobre os recursos naturais. A analise do uso e da ocupacao das terras e um ponto de partida para adequacao do ambiente antropico cuja capacidade de suporte e, portanto, fundamental para a criacao de modelos de gestao. O trabalho trata de uma pesquisa que utiliza o geoprocessamento e a gestao de informacoes do uso e ocupacao para estudos ambientais. O objetivo foi selecionar indicadores para gestao das Areas de Preservacao Permanente (APP) e aprimoramento do uso de informacoes para gestao ambiental. O estudo foi realizado na bacia hidrografica do rio Jundiai-Mirim, Jundiai, SP; utilizaram-se os dados de um levantamento previo das suas condicoes ambientais. A tecnica empregada permitiu a selecao de oito indicadores que se mostraram capazes de caracterizar o estado das areas avaliadas. Os resultados obtidos mostraram que somente 44,6% da APP se encontram em conformidade com a legislacao.

Monitoramento localizado da produtividade de milho cultivado sob irrigação

O aprimoramento do poder de gerenciamento agricola, atraves do aumento do nivel de informacao sobre etapas da producao, tem sido discutido como estrategia de decisao/manejo. O georreferenciamento obtido em tempo real na lavoura, pode permitir o estudo localizado das variaveis de solo e planta. No Brasil, a producao de graos apresenta grande demanda nesta linha, por ser expressiva e de grande potencial de absorcao tecnologica. Com o objetivo de se abordar alguns aspectos do aumento do nivel de informacao tecnologica em um ambiente agricola, um experimento foi instalado no ano de 1998, com a perspectiva de abordagem de lavoura de graos. O experimento foi estabelecido em Angatuba, SP. Em uma area de 34,3 ha, onde esta instalado um sistema de irrigacao tipo pivo central, monitorou-se a produtividade do milho na estacao de crescimento 99/00, alem do parâmetro fertilidade do solo. Os resultados evidenciaram regioes distintas na lavoura, com padrao de variabilidade diferenciado, que suscita discussao sobre suas causas de variacao. Dados preliminares de analise quimica do solo apresentaram baixa correlacao com a produtividade, em areas localizadas. A observacao da variacao de produtividade sugere o desenvolvimento de estrategias de manejo por zonas de atuacao, com base numa analise de tendencia dos fatores mais importantes que compoem a produtividade.

Environmental assessment using landscape analysis methodology: the case of the Jundiaí Mirim river basin, Southeast Brazil

Environmental damage and impacts from anthropogenic activities has led to the need for methodological development for its evaluation to subsidize environmental and human health management models. In this context, landscape analysis is a technique that incorporates a set of methods and procedures for understanding and explaining the structure, properties, indexes and parameters influenced by the occupation and use of the land. The main goal of this research was to present an environmental assessment methodology to represent the landscape, in simplified form, in order to identify environmental damage and impacts, to establish criteria and to propose management models for the Jundiai Mirim river basin, Sao Paulo state, Brazil. This approach integrates fundamental methodological procedures through compartmentation, stratification, highlighted elements, characterization and evaluation of the landscape, considering physical, biotic and anthropogenic indicators. The results show its potential for educational, research and extension proposals because of its simple and expeditious character. Therefore it was possible to obtain a landscape efficiency index, clear and objective, that promoted the understanding of the landscape. As guidelines for the river basin management we highlighted soil conservation plans, solid waste management and sanitation in urban areas, and land use planning to protect the supply reservoir of Jundiai city.