INTERACTION BETWEEN CLIMATE AND AGRICULTURE

Introduction
Climate and weather variability (departure from long-term averages) greatly influence the amount of physical productivity (yields) of agricultural crops, livestock including fisheries and forests, as well as the risk of failure of the productivity
Sustained economic yields are determined by among other things:
Extent and intensity of production as governed by average climate, and also
Probability or risk of the suppression of yield or even complete crop failure caused by day-to-day or season-to-season weather variability.

The terms Agroclimatology/agrometeorology are used to refer to the interaction between climatological and hydrological factors on the one hand and agriculture in the broad sense (including animal husbandry and forestry) as the other.
The aim of agroclimatology is to apply climatological information for the purposes of improving farming practices and increasing agricultural productivity in quantity and in quality.

The terms Agroclimatology/agrometeorology are used to refer to the interaction between climatological and hydrological factors on the one hand and agriculture in the broad sense (including animal husbandry and forestry) as the other.
The aim of agroclimatology is to apply climatological information for the purposes of improving farming practices and increasing agricultural productivity in quantity and in quality.


Agrometeorology/Agroclimatology is the application of meteorological/climatological knowledge, information and data to weather-sensitive problems in agriculture.
Agrometeorology tends to emphasize weather forecasting in dealing with daily problems, whereas agroclimatology is concerned with the use of mean data as a guide to long-range planning
Applications of climatic information to Agriculture

Land use planning
This involves selecting ecologically suitable and economically profitable crops and farming systems for a given region, or selecting the best sites for a particular farming enterprise within a large area. (covers aspects dealing with land use patterns, systems of agriculture and in particular crop zonation)

Agronomic practices (Management and operation.
Knowledge of Agrometeorology/Agroclimatology is critical in designing of agricultural calendars (i.e. dates of planting and harvesting), planning and management of Irrigation, fertilizer application, mulching, fallow, shading, mixed cropping and the use of farm machinery


In addition, crop-weather calendars are an aid in identifying the critical periods in the life cycle of crops when they are vulnerable to departures of weather from optimum conditions. These calendars may also help in land use planning, crop zonation and the identification of the likelihood of pests.

Crop-weather relationships
Knowledge of Agroclimatology/Agrometeorology will assist in a tremendous way in the understanding of crop growth and finally to yield formation as affected by plant processes much as photosynthesis, respiration, translocation, transpiration and other plant physiological processes.

Protective measures
The understanding of Agrometeorology/Agroclimatology is critical in the development of strategies aimed at combating adverse weather factors. This is essential in crop and livestock protection against factors such as frost, hail, flood, drought, soil erosion, wind damage and weather-related problems of pests and diseases

Monitoring
This is the making and recording of observations and the current interpretation of them in terms of the effects of weather on all project activities and on progress of plant development.
Weather monitoring is in fact an essential aid to the understanding of the reasons for successes, for failures or for yields fluctuation.
Monitoring also permits better day-to-day planning with lead times up to several days for forecasts of weather dependent pest and disease outbreaks or crop planting and ripening dates.
Farm-Weather forecasts
The elements such as air movement, thermal energy and water vapour which drive the atmosphere and cause weather (i.e. rain, wind, heat, cold, etc) are continually changing at every point on the earths surface. It is therefore quite essential to know what their future status will be.
Weather forecasts are classified according to the period of time for which the forecasts are valid, e.g. short range forecasts are valid for a period of a few hours upto not more than 48 hours. They attempt to give detail concerning the time and intensity of various weather factors over a given area.
Outlooks are normally for the day following a short range forecast and attempt to indicate the general weather fraud to be expected.
Medium range forecast are valid from three days upto 2 weeks ahead. They attempt to show the general fraud of weather and the approximate time of expected major changes.
Long range forecasts (or 30 day forecasts) are valid for a month ahead and indicate only the average conditions over a large area.
Crop forecasts
These are quite essential in giving advanced information on potential agricultural production for the purpose of planning national food strategies regarding export, import, local distribution, marketing, subsidies and relief.
Weather-based crop yield forecasting is based on the principle that weather from the time of crop sowing (or primordial initiation) up to a given time determines the yield potential of the crop at that time, as long as the weather continues normal from then until harvest time.
Numerical models exist or can be developed which interpret daily weather information in terms of quantitative yield estimates.
Mitigation of adverse factors.
Some meteorological factors can be modified for agricultural purposes by a number operational practices at farm level (shading serves to reduce excessive light intensity and windbreaks (or shelterbelts) to reduce wind damage, etc).

Soil mulching modifies soil temperature and evaporation. Irrigation aims at provision of optimum soil moisture conditions at every stage of crop cycles.

Irrigation efficiency, for example, often can be improved by a better understanding of the consumptive use of water by different crops in specific soil and climatic conditions. Over-irrigation without adequate drainage leads to water logging of the soil and salinity problems in some soils.

AGROMETEOROLOGICAL MEASUREMENTS

Growth of plants and animals are the result of the combined effects of genetic characteristics and their response o the environment.
Quantitative data is therefore required to assist in agrometeorological planning, forecasting, research and services to to meet the needs of agricultural producers (food and agricultural by-products)
Data will also assist in the assessment of impacts of agricultural activities and processes on the environment and climate.