01769naa a2200229 a 450000100080000000500110000800800410001910000180006024500630007826000090014152011960015065000100134665000100135665000150136665000100138165300130139165300140140465300150141865300120143370000230144577300710146811331892018-07-30       1986    bl uuuu     u00u1 u    #d1 aSHARMA, P. N.  aWater production function of sorghum for Northeast Brazil.  c1986  aThe results of an experiment to determine the water production function of sorghum for Northeast Brazilian conditions are reported. The experiment was designed in two random blocks consisting of four growth states for irrigation deficit and four levels of nitrogen. The crop response to water was found to be of quadratic nature. Regression coeficients were developed for each nitrogen and growth stage treatment between water use and grain yields. The most critical stage was found to be the vegetative stage followed by flowering and grainn formation stages. The yield response factors as according to Doorenbos and Kassam were found to with differente irrigation levels. A modified linear equation has been suggested. The coefficients of this modifieed equation have been determined for all four stages and for the four nitrogen levels for sorghum. The higest average water use efficiency of 109:3 kg haa-1 cm -1 of water and highest obtainable grain yield of 4.92 t/ha was found to be at 425 mm of water use and 45 kt/ha of nitrogen. The crop coefficients (Kc) to compute crop water use from pan evaporation vary between 0.4 and 0.81 with an average for the whole growing period of 0.75.  awater  aÁgua  aProdução  aSorgo  aNordeste  aNortheast  aProduction  aSorghum1 aALONSO NETO, F. B.  tAgricultural Water Managementgv. 11, n. 2, p. 169-180, apr. 1986.