Effects of two plant arrangements in corn (Zea mays L.) and soybean (Glycine max L. Merrill) intercropping on soil nitrogen and phosphorus status and growth of component crops at an Argentinean argiudoll

Intercropping systems can provide many benefits through increased efficiency of land and light use. The objectives of this study were to assess the main effects on a soil and plant growth of two arrangements of corn - soybean intercropping. In a 1-year experiment at 2011, the following treatments were randomly assigned in a CRD to 16 plots located on a vertic Argiudoll from Argentina: sole corn (Zea mays L.), sole soybean (Glycine max L.), corn-soybean 1:1 intercropping and Corn-soybean 1:2 intercropping. Nitrate levels were modified by treatments, but these treatments did not affect available P contents due to very high levels of this element during the whole cropping cycles. The practice of intercropping did not enhance water uptake by crops in relation to sole crops, as might be expected from complementary root systems and development timelines. Corn N status improved with intercropping probably due to an enhanced growth of plants and their roots, but soybean chlorophyll content was decreased by intercropping treatments. Yield and growth of corn were stimulated by intercropping systems, but this system depressed soybean growth, particularly at 1:1 corn-soybean ratio. Based on the remarkable dominance of corn crop observed at this arrangement, it can be concluded that a 1:2 corn-soybean ratio could be more beneficial in terms of more symmetric ecological interactions.