Monday, 17 September 2012
By B.V.R. Punyawardena
In spite of the technological advances made on improved crop management, irrigation, plant protection and fertilization; weather and climate remain the key factors of agricultural productivity in any country. Farming systems and agronomic practices in most agricultural regions of Sri Lanka have evolved in close harmony with the prevailing conditions of the respective climatic regions of the island. However, it has been made evident during recent decades that the heritage of farming experiences and accumulated weather lore of centuries are no longer useful in the process of agricultural planning at any level. The Climate of the island has undergone a change to such an extent that the expected rainfall does not come at the correct time and severely handicapping farmers during growing season. Variability of both summer and winter monsoon rains and rains of convectional origin has increased significantly during recent decades (Table 1). As a result, both extremes, i.e., water scarcity and excess water have become a recurrent problem faced by crop production in Sri Lanka. Meanwhile, increasing ambient temperature has also resulted in several direct and indirect negative impacts on crop growth. However, intensively managed livestock sector of the country is not so vulnerable to climate change compared to the food crops sector. But, the situation is obviously different for extensively managed livestock sector where it is purely dependent on the rain-fed pastoral systems. Meanwhile, additional pressure coming from ever-increasing population, poor terms of trade, weak infrastructure, lack of access to modern technology, and information and civil disturbances will restrict the options available for people to cope with the negative consequences of climate change (Punyawardena, 2002).
Monday, 3 September 2012
By C. Shanthi de Silva
Human activities have been recognized as the primary cause for global warming. The build-up of greenhouse gases (GHGs) threatens to set the earth on the path to an unpredictably different climate. A key challenge, in that instance would be food security, crucial to sustain the growing world population. An enormous amount of water is required to produce food. Irrigation needs vary according to the balance between rainfall and evapotranspiration, and the resultant fluctuations in soil moisture status. Anthropogenically induced climate change is expected to influence rainfall and temperature patterns. Since climate change will influence temperature and rainfall patterns, there are likely to be direct impacts on soil moisture. Changes in soil moisture due to global warming will have other hydrological effects which will, in turn, affect agriculture around the world.
Sri Lanka is no exception to this, as it is also prone to natural disasters. During the last few decades, for instance, Sri Lanka has witnessed a number of extreme rainfall events in south western regions during south west monsoon season (May to September) and in contrast northeast and north central regions experienced severe drought during the paddy and other field crop growing seasons. Farmers used to start paddy cultivation during maha season, expecting the north east monsoonal rains. Sri Lanka is experiencing uncertainty and inadequacy of north east and inter-monsoonal rains, during these years which caused damage to the paddy and other field crop cultivations. Each year, the Government of Sri Lanka spends huge amounts of funds on drought, floods and other, relief services.