Increasing species diversity through intercropping can be effective in improving the ecosystem functions and services. In this experiment, three different functional groups, soybean (Glycine max) as a C3 and fixing nitrogen plant, corn (Zea mays) as a C4 and nitrogen-demanding crop and marshmallow (Althaea officinalis) as a perennial medicinal plant, were cultivated as double and triple intercropping. The purpose of this study was to evaluate different patterns of intercropping in terms of production enhancement, weeds control, increase of nutrients uptake and improvement of soil biological properties as different ecosystem services and compare them with the sole cropping systems. For this purpose, two experiments were conducted based on strip design as a randomized complete block with three replications at research farm of Ferdowsi University of Mashhad in 2014 and 2015. Experimental treatments (14 treatments) were weeding and non-weeding, different planting patterns as double intercropping (corn + soybean, corn + marshmallow and soybean + marshmallow), triple intercropping (corn + soybean + marshmallow) and also their sole cropping. The results indicated that the highest density of weeds was observed by sole cropping of soybean among the different planting patterns in both years (46.7 plants per m2 in the first year and 47.3 plants per m2 in the second year) and the minimum number of weeds was observed under intercropping of corn + soybean + marshmallow with 37.6 plants per m2 for the first year and sole cropping of Marshmallow by 13 plants per m2 for the second year. Planting pattern treatment had no significant effect on Shannon–Weaver diversity index; however, the findings of the study illustrated that increasing plant diversity as intercropping caused to increase in weeds diversity. Among different intercropping patterns, the highest amount of nitrogen uptake was achieved from corn + soybean intercropping. In both weeding and non-weeding, phosphorous uptake in corn monoculture was higher than soybean and marshmallow monoculture, so that in the weed absence, phosphorus absorption in corn, soybean and marshmallow monocultures were 85.50, 46.66 and 44.51 kg ha−1 respectively. Using the intercropping systems increased the soil microbial respiration and biomass in comparison with sole cropping systems. According to the findings of this study, it can be mentioned that intercropping systems not only increase economic yield but also improve other ecosystem services.

Keywords