according to the respective crop profitabil it.•es. The modern farmers, who owned lU per cent of the lana at the D~ginning of the period, cul­ tivate 50 per cent of the total arabfe land to TlC. If the same tren~ is observed during the next five years. the share of land cultivated by moaern farmers wilJ be 65 per cent in Tl5. Thus the forecasts for Tl5 are as fol1ows in table 4. ---------------------------------------------------------------------Fa.-m type Traditional Moaern Total Oevidt.ion from first estimates (percentage) Arable Harvested lana area (Millions of hect -dres 0.35 0.65 1 0 0.175 0.547 o.122 18 P roc1uc t ion (Tho us a nels of tons) 140 656 796 Yield Fertilizers (T/ha) (kg/h a) (ftlOU SClflCIS of tons) o.so 1.20 1.10 -2 0 60 46 -30 0 33 33 -lll Table ~ shows that the use of aggregated data only tnouces sizaol e mistakes in the predictions: at the country level these mistak~s can be very costly (overcapacity of fertilizer pl~ntst bad design of the cereal importsreKports pQl icy. etc.). Another dra..,back is the lo~s of information on the cerea1 production system: with aggregated datd alone, the planner cannot understand the jual structure of the farmer population. and information about this structure is the corner-sto ne of any forecasting mode1 in this particular case. The disagsrerpted data prove that nei~her fertilization rates nor yields are price-responsive; thus it is rather easy to build up scenarios accord ­ ing to different evolutions of wheat prices (con;tant, increasing or decreasing prices). With ag-gregated data alone. such an exercise needs further hypotheses to fill the infor!lldtion gap; unfortundt ely. forecasting on the basis of too many ~Lar.ior.!. hypothe!:>es is quite a r&sky task and the probability of wrong estimates is high. 11 -ll - IV. CONCLUSIONS Information ~s ~n expensive commodity but a valuable one~ re~urns 
**Analysis**
The text discusses the use of aggregated data in predicting crop yields and the limitations of such an approach. It highlights the importance of disaggregated data to understand the structure of the farmer population and the relationship between prices and yields. The text also mentions the consequences of incorrect predictions, such as overcapacity of fertilizer plants and bad design of cereal imports.

**Category**
Agriculture, forestry and fishing, Economic development