Medicago polymorpha and M. sativa-camelina intercropping increases land use efficiency and productivity, and economic benefits in eastern China

Abstract

In the context of global food security and climate change, intercropping has been proposed as an effective agricultural practice to improve crop productivity and land use efficiency. The objectives of this study were to evaluate the total yield potential, land equivalent ratio, and economic benefits of one annual medic (Medicago polymorpha L.) and two alfalfa (M. sativa L.) cultivars intercropped with camelina [Camelina sativa (L.) Crantz] at two different seeding rates (15 and 30 kg ha⁻¹) in comparison with that of monocrops. Results showed that medic and alfalfa intercropped with camelina had greater land equivalent ratio (LER) value (∼1.63) and productivity than the monocropping systems. The intercropped camelina on average yielded (1045 kg ha⁻¹ across the planting pattern) 17 % less than that of monocrop (1261 kg ha⁻¹). Particularly, the seed yield of intercropped camelina + alfalfa ‘XJDY’ on average was 1295 kg ha⁻¹ (across the planting pattern), exceeding the mean seed yield of 1261 kg ha⁻¹ when it was monocropped, and produced the mean economic benefit of $3123 ha⁻¹, which was about 1.3–1.9-fold greater than each of the species monocropped. Additionally, although the forage nutritional values of Medicago species or camelina seed oil quality varied among the different intercropping systems, they fell within the ranges reported in other studies. As alfalfa can be harvested multiple times during the growing season, we would like to highlight the potential for double-season (spring and fall) planting of camelina into the alfalfa ‘XJDY’ considering the shorter growing cycle of camelina (about three months from seeding to harvest). In summary, the alfalfa-camelina intercropping in this study showed great potential to improve land use efficiency, enhance productivity, and increase economic benefits, and thus can be used as a promising way to support the development of sustainable agriculture.