SOME HYDROLOGICAL ASPECTS IN A NATURAL FOREST IN THE MID COUNTRY INTERMEDIATE ZONE OF SRI LANKA

Forests are considered to be hydrologically important land uses since forest environment influences significantly two main hydrologic processes, namely evapotranspiration and infiltration. These two processes are mainly responsible for overland flow and soil water storage in a forest. Understanding of the behaviour of these processes is very important for proper management of watersheds of the country. However, information on these aspects are very rarely available. Therefore, an experiment has been initiated in a natural forest in the mid-country of Sri Lanka to study the relationships among rainfall, runoff, and water storage in the soil profile. The data of the first year of work was analyzed to estimate the water loss from the forest vegetation, change of water storage in the soil profile and water extraction pattern from the different soil layers. The results showed that most of the rainfall was stored and used by the vegetation thus minimizing run off. Water loss by vegetation (evapotranspiration and interception ) varied with the rainfall and the soil water conditions

Desenvolvimento radicular do algodoeiro em resposta à localização do fertilizante Cotton root development as affected by fertilizer placement

A utilização de adubos pode-se tornar prejudicial caso o fertilizante não seja localizado adequadamente. No presente trabalho foram estudados o crescimento radicular do algodoeiro (Gossypium hirsutum), o crescimento inicial e a nutrição da planta, considerando o local de aplicação do fertilizante. O estudo foi realizado em vasos com parede de vidro. O fertilizante foi colocado a 5,0 cm abaixo e 0,0, 2,5, 5,0 e 10,0 cm ao lado das sementes. O crescimento radicular foi avaliado a cada três dias e, aos 21 dias após a emergência, as plantas foram coletadas, sendo avaliada a produção de matéria seca e a absorção de macronutrientes. A aplicação de fertilizante proporcionou crescimento inicial mais vigoroso do sistema radicular mesmo em solo previamente corrigido e adubado, o que é importante no estabelecimento da cultura. Somente houve bom crescimento inicial do sistema radicular e da parte aérea do algodoeiro quando o fertilizante foi aplicado de 5,0 a 10,0 cm ao lado e 5,0 cm abaixo das sementes.<br>Unless fertilizer is properly placed in the soil it can be harmful. This experiment was conducted to study cotton (Gossypium hirsutum) root growth and initial plant development and nutrition as affected by fertilizer placement. Cotton plants were grown in pots with a glass wall. The fertilizer was applied 5.0 cm under the seed row and 0, 2.5, 5.0 and 10.0 cm beside the seed row. Root growth was evaluated every 3 days, and 21 days after emergence the plants were harvested. Dry matter production and macronutrient absorption were evaluated. Even in previously limed and fertilized soil, localized fertilizer application reinforced the initial growth of cotton roots, which is very important for a good crop establishment in the field. Normal root growth and adequate initial plant development was only observed when the fertilizer was placed 5.0 cm below and from 5.0 to 10.0 cm distance from the seed row