Modeling Crop-Weather Interactions

摘要

Climatic parameters are the primary variables which define the agricultural productivity of any region and, therefore, the direct effects of climatic factors on crop growth and development have always been a subject of detailed investigations. Attempts have been invariably made through various regression models to predict the relationship between agricultural productivity and climatic components. However, such analysis that includes the effects of some climatic specific factors only excluding the interactions and feedbacks from other controlling elements can often lead to incorrect conclusions. In reality there are a large number of edaphic, hydrologic, biotic, agronomic and socio-economic factors that have a direct bearing on crop growth and productivity in addition to the climatic factors. Therefore, the response to climatic factors will invariably vary in different locations/experiments/years because of genotypic interactions with climatic variability, applications of external inputs such as irrigation and fertilizers, pests and disease incidence, and agronomic management practices. Agro-ecological zoning, which is crucial for planning agricultural development, is based on rainfall statistics and growing days. It may be adequate from a purely ecological point of view but it does not indicate much about the agricultural potential of the region. The growing period need not necessarily have a correlation with crop productivity. For example, it is more than 210 days in Assam and West Bengal, but the yield of principal rainy season rice crop is very low due to limited radiation and input use. On the other hand, the growing period in Punjab is only 90-150 days, yet rice yields are much higher due lo significantly higher radiation and input usage.