Productivity and risk evaluation in contrasting intercropping systems

Four contrasting intercropping systems (sorghum/pigeonpeas, groundnuts/pigeonpeas, sorghum/Pennisetum americanum and groundnuts/P. americanum) were evaluated along with sole crops from 1979 to 1982 at 9 different sites at Patancheru. Productivity of intercrops was closely related to the diversity of the crops involved. The 2 pigeonpea-based systems, with an interval of about 3 months between harvests, showed a large and consistent advantage over the respective sole crops. On the basis of land productivity, sorghum/pigeonpeas averaged 49% and pigeonpeas/groundnuts 53% advantage over their respective sole crop yields. These intercrops were also more profitable than the respective sole crops. The other 2 systems, with only 2-4 weeks between harvests of the components, showed a much lower and less consistent advantage. The groundnuts/P. americanum recorded 18% and the sorghum/P. americanum 7% advantage over their respective sole crops. Risk was measured by calculating the probability of success or failure of intercrops in satisfying specified quantities of yields and income in comparison with an optimal shared soil system having some of both sole crops. Pigeonpea-based intercropping systems had a lower risk than shared (or optimum) sole crops over a wide range of expected yields or income. There was no advantage for the sorghum/P. americanum intercropping compared with the shared sole crops at lower expectation, and for higher expectations sole sorghum should be preferred to the intercrop. Risk from groundnuts/P. americanum was less than from the shared sole system only in limited situations. Reduced risk of pigeonpea-based intercrops was associated with higher productivity and lower variability of combined intercrop yields or income. The methods employed in this study can be extended for risk evaluation in other intercropping and mixed system