Effects of plant density on the growth, reproduction and survivorship of cucumbers in monocultures and polycultures.
The growth, reproduction, and survival of cucumbers were studied in experimental plots with two spacings (56 and 77 cm between plants) and two diversities (monocultures, and polycultures with Zea mays and broccoli). Both density and diversity strongly affected plant growth and reproduction, but diversity effects were stronger and more consistent. Interactive effects between density and diversity were significant for growth only. Plants in monocultures had greater leaf areas, vine lengths, growth rates, numbers of flowers, and fruit yields than did plants in polycultures, and plants at low density had greater values for most of these parameters than did plants at high density. Leaf area distributions were positively skewed throughout the season in high density polycultures, and towards the end of the season in high density monocultures. Survival was affected by diversity only; plants had shorter lives in monocultures than in polycultures. For any given leaf area or number of flowers, yields were significantly greater in monoculture than in polyculture.