A field study was conducted on an experimental field of the Maize Research Institute Zemun Polje-
Belgrade (latitude: 44° 49′ N), Yugoslavia over a 3 year period (1994–1996). The objective of this
study was to find the optimal spatial arrangement of a maize–beans intercrop in irrigated and rainfed
farming systems.
Plant arrangement patterns in an intercropping system did not significantly affect LAI values in
maize compared with a sole crop, while irrigation had a greater positive influence on it. Leaf area
values of beans were more sensitive to the same treatments. Microenvironmental conditions in
maize–bean mixtures were more favourable for bean crop than for sole beans.
An intercropping system had a greater influence on yield components of maize. Component
combination 1/2[ratio ]1/2 (maize[ratio ]bean) was most effective in all yield components of maize. Intraspecific
competition appears to be more intense than interspecific competition in both crops. Yield
component of bean was more sensitive to water regime of the site than to planting pattern in an
intercrop. Irrigation increased all yield components of bean (especially pod number). The
intercropping system decreased harvest index in both crops compared with monocrops. Maximum
total grain yield was in 1994 in irrigated maize–bean intercrop 1/2[ratio ]1/2, with highest efficiency being
in an intercrop in irrigation in 1995. The Land Equivalent Ratio (LER), based on grain yield, was
consistently greater than 1·0 in an irrigation water regime in 1995. Proportion of maize[ratio ]bean
= 1/2[ratio ]1/2 gave the highest increase of yield (LER = 1·54). Under conditions of chernozem soil type in
Zemun Polje, with often-expressed dry periods, irrigation is a very important measure for increasing
maize–beans intercrop productivity.