In this paper, the role of crop shifts in the process of agricultural transformation is empirically investigated using newly-compiled production data of Punjabs agriculture for the period c. 1900-1995. The analytical innovation of this paper is that changes in aggregate land productivity are structurally associated with inter crop, inter-district, and inter-household reallocation of land use. In the empirical part, national data for India and Pakistan, district-level data for the Punjab region, and micro data of farm households are employed together. Quantitative results show that, first, a significant part of land productivity growth was attributed to inter-crop land re-allocation in pre-independence Pakistan and post-independence India and Pakistan. Second, agricultural transformation in Pakistans Punjab is characterized as the phase in which crop specialization according to comparative advantages plays a prominent role. In other words, diversification at the national level is yet to be observed in this area. Third, the pace of specialization was different from district to district during the colonial period, while the pace has been accelerated and become more homogeneous since independence. The time contrast reflects the spatial expansion and integration of agricultural produce markets in the region over this period.
