Monitoring and forecasting of sorghum yield in three areas of the mechanized rain-fed agriculture in the Sudan
2007
Hashim, Y.M., University of Khartoum, Shambat (Sudan).Desertification and Desert Cultivation Studies Institute | Mustafa, M.A., University of Khartoum, Shambat (Sudan).Desertification and Desert Cultivation Studies Institute
A study was undertaken to test the validity of an FAO method for monitoring and forecasting sorghum yield in three main sorghum production areas in the mechanized rain-fed subsector; namely, AI¬Gadarif, AI-Damazin and Kosti. The periods of crop development were determined from the relationships of mean normal (30 years) rainfall (Pn) and potential evapotranspiration (PET) versus IQ-days interval (decade) during the growing season. Annual water satisfaction indices (SI) were estimated for IQ years from annual water balance for the study period (1987-1996). This index indicates the extent to which the water requirement of the crop was satisfied in a cumulative way. Highly significant cubic relationships between Pn or PET and seasonal decades were obtained. The growing season of AI-Gadarif was semi-normal and that of AI-Damazin was typically normal, whereas that of Kosti was characterized by the absence of a wet period. An example for the calculation of SI for sorghum grown in 1987 in each of the three study areas was presented and analyzed. The correlation between sorghum yield and seasonal rainfall was highly significant (r2 = 0.747) and linear in AI¬Damazin area and significant (r2 =0.514) and cubic in Al Gadarif area. The relationship was not significant in Kosti area. The correlations between yield and SI was significant and cubic for AI-Gadarif (r2 = 0.537) and AI¬Damazin (r2 = 0.439) but not for Kosti. The pooled data gave a significant correlation (r2=0.127) between yield and SI index. However, the coefficient of determination was very low
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