Evaluation of Short-Term Effect of Oat (Avena sativa L.) and Chickling Pea (Lathyrus sativus L.) Cover Crops on Improving some Soil Properties

Continuous use of monoculture systems and excessive tillage has degraded agricultural soils in many regions of Iran. The short-term impact of cover crops on selected soil properties was investigated in a field study in 2018. The experiment was laid out as complete randomized block with three replications. The four experimental treatments included, monoculture of oat and monoculture chickling pea, their mixture, and no cover crop as control. Highest and lowest aerial biomass were 198.1 gm-2 and 124.1 g m-2 and obtained from mixed cover crop and sole chickling pea, respectively. The higher biomass resulted in significant weed suppression, compared with control. Weed dry weight reduced by 33.04% and 41.12% in oat monoculture and mixed cover crops, respectively. The highest soil organic carbon (1.21%) and highest microbial population (6.5 × 105 per gram of soil) were obtained from mixed cover crop experimental plots. Cover crop mixture, and monoculture of oat and monoculture chickling pea reduced soil compaction by 51.5%, 50.7%, and 49.1%, respectively. However, soil bulk density, soil porosity, and rate of water infiltration were not affected by cover crop treatments. Results obtained in this study indicated that short-term changes in some soil properties are related to both, biomass and cover crop species. Overall, a mixed of cover crops was more influential on changing soil properties.