Geoinformatics Solutions for Integrated Agro-ecosystems Research
Length of the moisture-limited growing period
The climatic growing period is calculated by means of a model developed by the Food and Agriculture Organization of the United Nations (FAO, 1978) to estimate the length of growing period under either moisture-limiting or temperature-limiting conditions, or both. Under rainfed conditions, both moisture and temperature can be limited. Under irrigated conditions, only temperature is to be considered a limiting factor.
The moisture-limited growing period is calculated, using a waterbalance approach, as the ratio of actual evapotranspiration (AET) to potential evapotranspiration (PET). If this ratio for any particular month is higher than a user-defined threshold (in this study 0.5), that month is part of a growing period. If it is not, that month is not part of the growing period. The start date of the moisture-limited growing period is obtained from linear interpolation of the AET/PET ratios between the last month that is not part of the growing period, and the first month that is part of the growing period. The end date, inversely, is obtained by linear interpolation of the AET/PET ratios between the last month that is part of the growing period, and the first one that is not part of the growing period.
The climatic growing period is calculated by means of a model developed by the Food and Agriculture Organization of the United Nations (FAO, 1978) to estimate the length of growing period under either moisture-limiting or temperature-limiting conditions, or both. Under rainfed conditions, both moisture and temperature can be limited. Under irrigated conditions, only temperature is to be considered a limiting factor.
The moisture-limited growing period is calculated, using a waterbalance approach, as the ratio of actual evapotranspiration (AET) to potential evapotranspiration (PET). If this ratio for any particular month is higher than a user-defined threshold (in this study 0.5), that month is part of a growing period. If it is not, that month is not part of the growing period. The start date of the moisture-limited growing period is obtained from linear interpolation of the AET/PET ratios between the last month that is not part of the growing period, and the first month that is part of the growing period. The end date, inversely, is obtained by linear interpolation of the AET/PET ratios between the last month that is part of the growing period, and the first one that is not part of the growing period.