Carbon farming methods: Crop residue management

Well-managed farms maximize crop output. But what happens when soil health is also prioritized? Carbon farming methods are utilized to manage outputs by taking care of the soil to provide new forms of profit for farmers.

Carbon farming isn’t one solution, rather, a variety of techniques to manage arable land in a way that it accumulates as much carbon as possible which affects soil quality and yield. Carbon farming techniques include cover crops, optimized tillage, and fertilizer management to name a few.

This guide highlights crop residue management as one of several carbon farming methods a farmer can adopt when it suits the particular needs of the farm. Crop residue management will be covered in the following sections:

What is crop residue management?

Once crops are harvested and threshed, leftover plant materials remain on the fields. Apart from removing crop residue like straws in the fields is to use them as animal feed. Alternatively, burning residue is also practiced which could help with pest management but increases farm emissions as well as loss of nutrients and beneficial soil microorganisms.

Crop residue is removed to make sowing more manageable. But disposal and burning are not the only ways to deal with crop residue. Instead of treating it as a waste by-product, post-harvest crop materials can be an important part of the farm’s sustainability.

Managing crop residue is widely accepted as a method that improves farm soil and resource use efficiency. Crop residue management is often understood as retaining leftover crop materials to keep soil surface cover and for soil protection against nutrient loss and erosion.

Mulching can be considered a crop residue strategy suitable for carbon farming, specifically organic mulch materials like straw and hay. Mulching can also incorporate other materials such as grass clippings, peat moss, and other inorganic mulching materials. But keep in mind that in carbon farming, the concept of non-leakage must apply. This means that when a practice is applied, doing so should not incur losses in soil carbon in some other place.

The benefits of sustainably managing crop residue

Considered waste to some, recycling residue from crops can become a valuable resource that enriches the farm in 3 main areas:

Soil benefits:

• Improves physical properties of soil that help with water-holding capacity and drainage.

• Lessens incidences of erosion

• Helps retain ideal soil temperature

• Improves the soil acidity and availability of micronutrients

• Beneficial for soil microbial life

• High-quality organic matter content

• Soil carbon enhancement

Agronomic benefits:

• Retains soil productivity

• Recycles nutrients from the soil

• Better root proliferation

Economic benefits:

• Can improve crop yields

• Generates new income sources with carbon farming

Evidence suggests that sustainable crop residue management used in conjunction with conservation tillage strategies generates even better outcomes.

The indiscriminate use of chemical fertilizers has reduced the quality of soils used for growing high-quality crops. Declining yields have been observed due to poor soil quality, and therefore, loss of revenue for farmers. Relying on more fertilizer use is costly and can even bring down dwindling farmer profits.

Sustainable crop residue management is a farming practice that helps with managing fields and the costs of farming.

Why crop residue management works in carbon farming

Carbon farming in a nutshell

Carbon is crucial for life on earth. For plants to thrive, carbon is derived from the soil where they get to retain it even after harvest. Burning residue means carbon escapes into the atmosphere instead of keeping it in the soil where it is beneficial for cultivation and soil properties.

Carbon farming gives new profit sources to farmers by getting as much carbon back into the soil instead of letting it emit into the air where it causes extreme weather events and rapid climate change. In fact, carbon farming benefits the farm beyond carbon sequestration.

Crop residue management is but one of the several farm practices farmers can incorporate to increase soil carbon storage. Other ways are:

• Reduced fertilizer application

• Reduced tillage

• Improved residue management

• Eliminating bare fallows

• Increased production of cover crops

• Sowing companion crops

• Agroforestry

• Improved task efficiency

• Improved water management

• Fuel-use efficiency

Sustainable crop residue management

Potential to limit farm emissions

Agriculture contributes to greenhouse gas emissions, just like most human activities. In particular, the entire agricultural industry emits somewhere between 10-30% of heat-trapping gasses globally that cause climate change. Carbon farming is a solution that doesn’t just maintain soil health, it also helps manage the emissions the agricultural industry produces. Thereby turning carbon as a waste material into a reliable resource for profit, yield, and sustainability.

By not burning residue from crops, excessive methane and nitrogen emissions can be limited to bring down farm emissions, effectively.

Enhance soil carbon content

By retaining leftover crop material like stubble, husks, stems, straws, leaves, etc., a protective and nourishing barrier is formed for soil health. These materials contain carbon that when left to incorporate with the soil and the microbial life in it enhances the organic carbon content of the soil, among other beneficial effects. Instead of being treated as a waste material that leaks greenhouse gasses into the atmosphere, it can improve soil fertility with the addition of carbon in the soil through sustainable crop residue management.

Incorporating carbon farming methods like stubble retention

Every farm is different. One thing to consider when carbon farming is how suitable it is as a practice for a farm’s unique characteristics. This is where a carbon program can help define the best practices for a particular farm.

Guided by baseline measurements and advice from experienced agronomists, crop residue management can be recommended to a farm’s practice plan to achieve desired results to generate high-quality carbon credits for income.

Just like other carbon farming methods, the applicability of crop residue management isn’t straightforward as well. Certain conditions can have it be recommended at different levels — between 10-50% stubble retention or leaving everything altogether.

Find out how our carbon farming program can help with income for farmers through carbon credits.

Sources

• Sarkar, S. et al. Management of Crop Residues for Improving Input Use Efficiency and Agricultural Sustainability. Sustainability 12, 9808 (2020). https://doi.org/10.3390/su12239808

• Conteh, A.; Blair, G.J.; Rochester, I.J. Soil Organic Carbon Fractions in a Vertisol Under Irrigated Cotton Production as Affected by Burning and Incorporating Cotton Stubble. Soil Res. 1998, 36, 655–667.

• Rakesh Maurya, Chandrabhan Bharti, Thokchom Dorenchand Singh and Vijay Pratap. 2020. Crop Residue Management for Sustainable Agriculture.Int.J.Curr.Microbiol.App.Sci. 9(5): 3168-3174. doi: https://doi.org/10.20546/ijcmas.2020.905.376

• Witzgall, K., Vidal, A., Schubert, D.I. et al. Particulate organic matter as a functional soil component for persistent soil organic carbon. Nat Commun 12, 4115 (2021). https://doi.org/10.1038/s41467-021-24192-8