Contents & Foreword, Characterizing And ... - IRRI books

where x it = quantity of input i in period t, s it = share of input i in total cost in period t;w it , w kt = actual prices of inputs in period t. Similarly, the output index is computed aswhere q jt = quantity of output j in period t, r jt = share of output j in total revenue inperiod t,p jt , p it = actual prices of outputs in period t. Finally, the TFP index is obtained as theratio of I(Q) t /I(X) t .The computation of these indices follows the following procedure. For eachyear, all crop outputs produced and all inputs used were included in the calculation.Analysis was limited to the period 1992-97 as the data for 1991 and 1998 were incomplete.A combination of province-level and farm-level data was used in the analysisas farm-level data for 1992-94 did not include all outputs for all farmers. On theoutput side, provincial-level data on yield and farm-gate prices for 1992-97 wereused. For the cost of production, data for individual crops for each year were notavailable at the provincial level. Hence, farm-level data were used for this purpose.Indices of the value of outputs and inputs were subsequently obtained using equations(1) and (3).Results and discussionI(X) t = I(X) t – 1 exp[1/2Σ (s it + s i, t – 1 ) ln x it – ln x i, t – 1 )] (1)iw it x its it = , i,k = 1, ... n, and (2)Σw kt x ktI(Q) t = I(Q) t – 1 exp[1/2Σ (r jt + r j, t – 1 ) ln q jt – ln q j, t – 1 )] (3)jp jt q jtr jt = ; i,j = 1, ... m, and (4)Σp it q itCropping patternsRice is grown in most of the farmlands during the WS, except for small areas in thehigher toposequence that are planted to vegetables such as beans, eggplant, and tomato.Most of the farmers plant modern rice varieties. In the 1996 and 1997 WS,IR64 and PSB Rc14 were the most popular varieties planted, occupying 24% and25% of the rice area, respectively (Table 1). BPI Ri10 remained a common varietyamong farmers. Other IR varieties covered almost 25% of the total area planted in thelast two years.During the DS, farmers plant high-value cash crops such as garlic, onion, tomato,sweet pepper, and tobacco. These crops are entirely dependent on irrigationfrom shallow tube wells. Vegetables such as eggplant, bitter gourd, bottle gourd, squash,396 Lucas et al