Based on these parameters,and the knowledge of the soil and crops characteristics for each region,water balance estimations and drought indices are determined and weather reports are provided twice a week to emphasize the agrometeorological aspects and climate for agriculture and crop development.Maps of water restriction in the soil,agricultural drought indices,rainfall irregularities and thermal stress are provided weekly,in order to evaluate the impact of the meteorological constraints and its variability on crops.
The most important aspect refers to the evaluation and monitoring of drought and the economic and agronomic aspects affected by this phenomenon.The intensity of the drought is estimated by agrometeorological indices such as the ratio between the actual over the potential evapotranspiration,and available soil water,or even by the combination of differents aspects of soils , weather and crops.Currently, the montlhy quantification of the drought is made by the use of the Standardized Precipitation Index (SPI) combined to the Palmer Drought Severity Index(PDSI).In order to emphasize the agronomic effects of the drought,the meteorological irregularities and crop growing period,the PDSI has been used on a ten days period.
Other specific indices to quantify water deficits based on the water balance as proposed by Thornthwaite- Mather,are used for evaluating crop yield reduction for corn,soybean and coffee.
The weather bulletins and agrometeorological advises are disclosed by newspaper,TV,internet,fax and can be accessed through the web sites www.iac.br/~ciiagro or www.cpa.unicamp.br.These bulletins and the agrometeorological advises are used to provide subsidies for mitigation and control of the drought in the field of action of the São Paulo State Agriculture Department and Water Resouces Department.
Supplementary URL: http://www.iac.br/ciiagro