Effects of compost incorporation on greenhouse gas emissions, N retention, and crop yield at two different P levels: results from a two-year lysimeter experiment with silty loam soil

Abstract

Abstract Purpose Compost has great potential for use in sustainable agriculture. Stoichiometric relationships between C, N and P play an important role in soil biogeochemical processes. The aim of this study was to quantify greenhouse gas (GHG) emissions, soil nutrient retention and leaching, aboveground biomass and crop yield at different soil C:N:P ratios. Methods The lysimeter experiment included six treatments: (1) without fertilization and seeding (bare), (2) common P fertilization (control), (3) P fertilization at twice the common level, (4) compost addition of 40 t ha-1 and common P fertilization, (5) compost addition of 40 t ha-1 and P fertilization at twice the common level, and (6) compost addition of 80 t ha-1 and common P fertilization. Treatments 2-6 were all fertilized at the same N level. Results Compost application significantly increased aboveground biomass and grain yield, particularly in the double compost treatment, where the variability between replicates was particularly low. However, the effect of compost application on GHG emissions was insignificant. Addition of 80 t ha-1 of compost increased dissolved organic carbon (DOC), compared to the control, but did not lead to a significant increase in DOC, N and P leaching losses. In contrast, bare soil resulted in significant leaching losses of DOC and nitrate (NO3–) compared to plant-covered treatments. Conclusion We conclude that combined compost and N fertilizer application is a suitable management option for increasing crop yield and reducing its variability, as it does not lead to increased GHG emissions and leaching losses of NO3– and P.