Sustainable Fertilizers
Fertilizer that is derived from organic sources, including organic compost, herbivore manures, vermiculture, microbial soil amendments, and domestic sewage.
Compost amendment to enhance carbon sequestration in rangelands
Rangelands, which hold 20% of the world’s soil carbon, have experienced significant soil carbon losses due to past management practices, jeopardizing their long-term productivity and sustainability. Compost amendments have been proposed as a strategy to enhance soil carbon sequestration while providing multiple benefits to rangeland ecosystems and land managers. A review of the literature reveals that compost applications, derived from sources such as green waste, food waste, manure, and biosolids, have been studied in rangelands across eight countries and five continents. These studies have documented both short-term (less than one year) and long-term (over 12 years) effects of compost on soil and plant characteristics. On average, compost amendments were found to increase aboveground production by over 40% and belowground carbon content by 50%. Additional benefits of compost amendments included improved aggregate stability by approximately 42%, enhanced water retention by 18%, and increased nutrient availability, with nitrogen and phosphorus availability rising by 37% and 126%, respectively. Compost additions also generally reduced erosion, though the variability was high. However, the impact on plant diversity was minimal, and few studies explored the effects on soil microbial communities and functions. Both field and modeling studies indicated that compost amendments could lead to long-term carbon storage in soils. Overall, the findings suggest that compost amendments can improve rangeland resilience to climate change and offer a viable climate mitigation strategy through enhanced soil carbon sequestration.
The climate change mitigation potential of annual grasslands under future climates
This study investigates the impact of composted manure and green waste amendments on carbon sequestration in rangeland soils and their potential to reduce atmospheric CO2 levels. It also examines how future climate changes might affect soil organic carbon (SOC) stocks and greenhouse gas emissions in these ecosystems. Using the DayCent biogeochemical model, the researchers simulated the long-term effects of climate change on carbon dynamics in annual grasslands, both with and without compost amendments. The simulations, based on data from seven California grasslands, used climate projections from two Earth system models (CanESM2 and HadGEM-ES) and two emissions scenarios (RCP4.5 and RCP8.5) through 2100.