Country and economy wide agriculture productivity can be obtained from the UN Food and Agriculture (FAO) agency website at;

http://www.fao.org/statistics/en/

Also consider the following articles accessible by the following links;

1. https://www.academia.edu/13837438/Input_and_output_technical_efficiency_and_total_factor_productivity_of_wheat_production_in_Tunisia

2. https://www.academia.edu/18535857/Efficiency_and_Technical_Change_in_the_Philippine_Rice_Sector_A_Malmquist_Total_Factor_Productivity_Analysis

3. https://www.academia.edu/2628071/An_evaluation_of_technical_efficiency_and_agricultural_productivity_growth_in_EU_regions

4. Article Agricultural Growth Accounting and Total Factor Productivity...