Crop Damage due to Frost across two Diverse Agro-environments

In the frame of climate monitoring the great attention is paid on analysis of extreme weather events such as frost occurrence, cold waves and freezing spells because they effect people and agro based economies to a great extent. Frost damage occurs when ice forms inside the plant tissue and injures the plant cells. Crop plants that develop in tropical climates, often experience serious frost damage when exposed to temperature slightly below zero, whereas most crops that develop in colder climates often survive with little damage if the freeze event is not too severe. The two diverse agro-envronments viz., one, the continental climate represnted by Croatian interior which includes Zagreb where mean minimum temperature in winter ranges from -11.4°C to -6.0°C while the second, the tropical climate represented by Haryana province in NW Indian plains where a few events of sub zero temperature observed during the winter season. Low temperature (e.g. chilling and freezing) injury can occur in all crop plants, but the mechanisms and types of damage vary considerably. Many fruit, vegetable and ornamental crops of tropical origin experience physiological damage below 12.5°C, hence well above freezing temperatures. However, damage above 0°C is chilling injury rather than frost injury. Recently in April, 2016 in Croatia, frost occurrence caused severe damage in apples, pears, cherries and grapes and the damage was estimated well above 105 million Euros. In Haryana province of India too, due to frost occurrence, the crop plants failed to photosynthesise turning into pale or brown particularly in Potato, Peas, Tomatoes and Capsicum crops. Similarly, the loss to other vegetables and fruits particularly ber, papaya and guava was 20 to 50 per cent. The Brasica spp plants (upto 10 %) were infested with rust disease due to extreme cold and frost conditions by which plant leaves turn yellow or brown in colour. In the light of the losses due to frost cited above, it is needless to emphasize the forecast value of frost warnings. With medium range weather forecasts and weather-based farm-advisories both for continental and tropical climates, frost forecasting on a regional basis is possible. There is scope and need to evolve contingent measures for implementation after issuing of early warnings on cold wave, frost events particularly with reference to individual crop species, vegetable crops and fruit tree plantations to mitigate the adverse effect in a more systematic manner so as to mantain the sustainable crop production in both the agro-environments.

Keywords: Crop damage, frost, agro-environment, weather forecast, farm advisory