One of the tasks of agricultural ecologist is to increase agricultural yield． How to improve agricultural practice is
the biggest challenge in drought and barren environments on the Loess Plateau． Many studies have attempted to increase
yield through the integration of plant population density，water and fertilizer use efficiency in this region． Intercropping，
which is the simultaneous growing of two ( or more) crop species in the same field，is a good solution to resolve this
problem． Especially under low input conditions，the high yield attributes to resource complementarity in the intercropped
system in which the component crops use the resources efficiently by dynamically balancing the different absorbing time，
space-occupying or phenology． Maize ( Zea mays L． ) and soybean ( Glycine max L． ) are important crops in China selected
as the inter-planted crops． A field experiment was conducted to investigate the yield and economic benefit in the intercropsof maize ( Zhengdan 958 and Yuyu 22) with soybean ( Zhonghuang 24 and Zhonghuang 13) in two planting patterns ( 2∶ 2
and 2∶ 4) respectively on the Loess Plateau，and the sole crops set as controls． Based on the interrelation between varied
components and planting patterns as well as their relation to crop yield，competition indices，economic indices and water
use efficiency under intercropped，we look forward to understanding potential regulation and mechanisms of maize /soybean
intercropped system and serving for the agricultural production． The aboveground biomass，grain yield and water use
efficiency were surveyed in each planting pattern． Several indices of competition and economic were calculated and used to
evaluate the intercropped systems and analyze the competitive relationships between intercropped components． The results
showed that the land equivalent ratio ( LEＲ) and relative crowding coefficient ( K) were greater in maize-soybean
intercropping than that in sole crop，indicating an advantage of intercropping． Yield of maize in maize-soybean intercropping
was higher than that in single crop． The actual yield loss ( AYL) ，aggressivity ( A) and competitive ratio ( CＲ) indicated
that maize was the dominant species in maize /soybean intercropped system． Zhengdan 958 and Zhonghuang 24 showed more
competitiveness on the water than the other two varieties in intercropping cultivation． The highest values of monetary
advantage index ( MAI) and intercropping advantage ( IA) were recorded by the intercropping pattern of Zhengdan 958 and
Zhonghuang 24 ( with 2 ∶ 4) ． The highest water use efficiency of maize was in intercropping pattern of 2 ∶ 4，followed by
intercropping pattern of 2∶ 2，and sole crop was the lowest． As mentioned above，maize and soybean intercropped system
had an obvious advantage in enhancing yield． The increases in biomass，yield and water use efficiency were caused by
different varieties interaction and plant patterns significantly． Zhengdan 958 intercropped with soybean ( Zhonghuang 24 and
Zhonghuang 13) had advantage，indicating that Zhenggdan 958 is able to improve intercropping advantage． Zhengdan 958
and Zhonghuang 24 intercropped in patterns of 2∶ 4 obtained the highest yield and water use efficiency among all treatments．
Therefore，we suggest that Zhengdan 958 and Zhonghuang 24 intercropped in patterns of 2 ∶ 4 had the highest economic
benefit than the other patterns and thus may be adopted and popularized by farmers．
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