Achievements - Land and water management

Rejuvenation of degraded RBE soil

Continuous farming on same land causes degradation of soil. The fallowing of such land is a widely adopted practice for many years. However, soil amelioration by fallowing the land is a lengthy process. Therefore, it is essential to find methods to accelerate the rejuvenation process in soil to maximize the agriculture intensity to meet the use of land.

Studies were initiated in this respect and continued by using Citronella and Sunnhemp as vegetation. Result shows that the adoption of grass with 7 seasons increases the dry and wet aggregate stability by 12 and 17%, soil available water at 0.1 bar suction by 21 %, exchangeable K by 45 %, and OM by 25% and adoption of sunhemp increases the dry and wet aggregate stability by 8 and 10 % and exchangeable K by 44 %.

In-situ rainwater harvesting systems for OFC and vegetable

For the establishment of OFC and vegetable crop during yala season in up lands, in the absence of irrigation facilities there is a need to collect and store rainwater during wet periods and supply to the plant during dry periods. Therefore, a study is initiated to innovate an effective rainwater harvesting system for OFC and vegetable crop establishment. Cowpea crop was cultivated with buried coconut husk as it absorbs moisture during wet period and provides moisture to the plant during dry period. Significant yield difference was not observed so far as the rainfall received in the field was sufficient enough during the cropping period.

Crop Growth Prediction Models

Series of experiments were carried out to develop a crop growth performance prediction model with climatic variations for a given soil. Two experiments have been carried out in 2002.

The amount and variations of soil parameters such as phosphorus, potassium, pH, organic matter, salinity and texture were tested for sampling and yield estimation in Mahakanumulla cascade in Anuradhapura district. Maps are being prepared.

For the determination of crop yield with the dates of planting the behavior of rainfall and the occurrence of dry spells are studied. According to the rainfall at MI from 1905 to 2002, number of consecutive rainless days at 75% probability based on 20 year intervals does not differ much. It is 6 to 8 or less days in maha season (01st Oct. - 29th Feb.) and 16 or less days in yala season (1st March - 30th Sept.) Experiment will be carried out for further studies based on growing periods of different crops.