Photo credit: STRATUS
Calculating an organic matter balance provides insights into the inputs and outputs of organic matter within an agricultural system. Organic matter plays an important role in maintaining soil health, contributing to improved water retention, soil aeration, structure, and carbon sequestration. While many farmers recognise the importance of organic matter and understand the need to preserve or enhance its levels in the soil, the quantification of organic matter inputs and outputs is often overlooked. This is especially true over longer periods, where monitoring the organic matter balance over multiple years is rarely done.
By accounting for both the inputs and outputs of organic matter, farmers can get a clear understanding of their farming system’s long-term sustainability and the impacts on soil health. Inputs include sources such as crop residues, animal manure, cover crops, and compost. The output of organic matter is its degradation, which is influenced by factors such as microbial degradation, crop growth, soil tillage practices, and external environmental conditions like rainfall and temperature.
Estimating the degradation of organic matter might be challenging. However, there are standardised values that estimate the organic matter degradation rate per crop. Additionally, models that include additional factors like temperature, soil type and moisture can be used to make more precise estimations on the organic matter degradation rate.