Effects of different size fractions of municipal solid waste compost on growth of Lolium perenne L.

Physical fractionation of a municipal solid waste compost was performed by a dry sieving process to obtain two particle size fractions (> 1.6 mm and 0.8–1.6 mm). The compost with the two particle sizes and the whole unfractionated compost were applied to field soil, and the effect of different size fractions of compost on the growth and physiological characteristics of Lolium perenne L. were investigated. The results showed that the plant height and shoot biomass of L. perenne were higher in the treatments with the whole compost and > 1.6 mm size fraction compared with the control throughout the growing season, but the difference between treatments decreased gradually. The chlorophyll content in these two treatments was also higher than that in the control. The biomass, chlorophyll b, and total chlorophyll content of the second harvest were 23.8%, 82.1%, and 13.9%, respectively, higher in the > 1.6 mm size fraction treatment than in the control. In addition, L. perenne had a dark green color and uniform plants in the > 1.6 mm fraction treatment, which scored the highest in the comprehensive evaluation of turf quality. Plants treated with the coarse fraction of > 1.6 mm showed a strong photosynthetic capacity and maintained a high protective enzyme activity and proline content to improve stress resistance.