Effects of applying mixed composting of municipal sludge and garden waste on growth of Amorpha fruticosa and soil environment

ObjectiveThe optimal conditions for the growth of Amorpha fruticosa were determined by observing the effects of different ratio of mixed composting of municipal sludge and garden waste and different application amount on its growth and soil environment, in order to maximize the processing of municipal sludge and garden waste, and provide the scientific basis for the circulation of garden waste and municipal sludge.

MethodA pot-based experiment was designed with four different compost products and different dosages in Beijing. Two kinds of materials were mixed at four volume ratios (0:1, 1:3, 1:1, 1:0, marking as GF, SGA, SGB, SS), and each compost was put together with soil at different volume ratios (0, 25%, 50%, 75%, 100%, marking as CK, T₁, T₂, T₃, T₄).

ResultThe results showed that seed germination of A. fruticosa was inhibited when the application of four kinds of compost products was 100%. SS showed a high inhibitory effect on each application. Compared with the control, the growth of A. fruticosa was slower in the early stage of fertilization, but accelerated at later phase. The growth rate of A. fruticosa treated with the compost products exceeded than treated without compost product, and its growth gradually showed the nutrition effect of organic fertilizer. The biomass of above ground and underground were significantly increased after composting, and the maximum values appeared in T₂ and T₁ of the treatment of SGB and SS, respectively. The application of composting products can improve soil physical and chemical properties. Soil total nitrogen, total phosphorus, total potassium, organic matter content and soil electrical conductivity increased significantly with the increase of the amount of fertilizer, and the activities of soil urease, alkaline phosphatase and dehydrogenase were improved after applying composting products. Soil environment was improved at the same time.

ConclusionThe application of 50% SGB is most beneficial to the growth of A. fruticosa. In summary, 50% SGB is the optimal application proportion.