Specific Farm Humus Management
The management of humus on the farm aims to maintain or increase the soil humus content in the long term. It involves supplying the soil with biomass and maintaining it through various methods to promote humus formation.
Important practices in humus management include crop rotation, green manure and undersowing, composting, and (reduced) tillage. These methods help accumulate organic matter in the soil or maintain it at a high level, thereby improving soil structure, increasing water and nutrient retention, and preserving soil fertility in the long term.
Many measures for sustainable humus management can be easily integrated into common agricultural practices. Experience shows that with interest, observation, and a little patience, it is possible to find solutions for each farm. However, humus management remains a continuous learning process.
Planning a humus regeneration strategy on your farm
Planning a humus regeneration strategy requires knowledge of the influencing factors at the farm level. How to best use these factors? The following four steps allow these factors to be used for optimal humus management.
Assess the current situation
The online tool humusbilanz.ch allows calculating a humus balance for the entire crop rotation and farm. The humus calculator indicates whether the crop favors or decreases the humus content. The humus balance compares the input and degradation of organic matter taking into account clay content, pH, and crops grown. The input of organic fertilizers is also considered.
The humus balance provides a rough estimate per plot as well as for all plots combined. Personal observations and additional parameters can help assess, beyond the humus balance, the situation on one’s own farm and identify possible deficits:
Soil condition
- Are there cultivated areas showing signs of erosion?
- Are there areas threatened by erosion and cultivated for agricultural or horticultural purposes?
- Are there problems with crusting or compaction?
- Are there places where plants show growth problems?
Tillage
- How and how often are tillage operations performed?
Closed cycles
- Are cycles well closed on the farm? Are fodder and straw returned to the cultivated areas as manure, compost, and slurry?
- Do large quantities of fodder, straw, or harvests leave the farm?
Crop rotation
- What is the proportion of humus-consuming crops and humus-producing crops?
Undersowing, catch crops, and green manure
- Are these measures already integrated into the crop rotation?
Fertilizer and other carbon sources input
- Are fertilizers purchased from outside the farm?
- What is the C/N ratio of the applied fertilizers? Are they used for fertilization (N in large quantities) or for humus formation (C in large quantities)?
Identify possibilities on the farm
The type and extent of improvement possibilities vary from farm to farm. The answers to the following questions can provide indications of possible improvements.
Tillage
- Is it possible to reduce the use of the plough?
- Is it possible to reduce the intensity of tillage before certain crops?
- Is it possible to completely omit certain tillage steps?
Crops
- Which are the humus-producing crops that could enrich the crop rotation?
- Do crop residues remain on the fields, within the nutrient cycle of the farm, or do they leave it?
Green manure
- Are there crop breaks longer than 4 weeks during which no green manure is sown?
Undersowing
- When summer establishment of cover crops is difficult, is it possible to implement undersowing (cereals, oilseeds, maize, faba beans)?
Input of carbon supports
- Does the nutrient balance allow the addition of extra carbon sources, such as compost?
Specific management / inter-field modulation
- Is it possible to avoid crops with low soil cover on areas sensitive to erosion?
- Is it possible to replace arable land with permanent grassland on sloping terrain or to integrate grass strips where slopes are steep?
Soil pressure
- Is it possible to reduce the weight of machinery?
- Is it possible to reduce the number of passes in grasslands and crops?
Soil compaction
- Can compacted soils be loosened deeply?
Extensification
- Is it possible to carry out targeted extensification of areas influenced by stagnant moisture or groundwater?
Implementation of measures
In some cases, it is not possible to adopt a fully coherent humus management on a farm due to market conditions, labor constraints, or societal issues.
The long-term benefits of effective humus management must be balanced with other farm interests. The easiest and most promising measures to implement on the farm should be prioritized.
To minimize financial risks, it is recommended to implement changes gradually and progressively adapt practices that have proven effective so far. In case of doubt, it may be wise to first test measures on partial areas. This allows verifying short-term feasibility and considering medium- and long-term impacts.
Monitoring effectiveness and adapting measures
Soil processes are complex and, regarding humus content, they can sometimes only be identified and measured after many years. Since humus contents vary greatly within plots due to soil type, but also throughout the year and crop rotation, depending on weather conditions and crops, it is difficult to assess the effectiveness of a specific measure.
Due to the complexity of humus dynamics in the soil, it is recommended to think long-term regarding measures that promote humus formation and to document actual changes over several years. Surveys and photos can be useful for documentation. To enable comparison, it may be helpful to maintain usual cultivation techniques on part of a plot (control) or to omit a chosen measure.
Changes in soil and plant growth must be considered both short- and long-term and measured using different tools. Various methods can be used to verify results. Ideally, they should be combined: spade test, yield survey, analytical measurement of humus content (soil analysis), and humus balance.
For further information
- Technical sheet «Humus management» (FiBL Shop)
- Technical sheet «Soil analyses for organic farms» (FiBL Shop)
- Humus balance Agroscope (humusbilanz.ch website)
- Spade test SolDok (instructions, forms, videos, app): (testbeche.ch website)
- Technical sheet «Soil protection and crop rotation» (FiBL Shop)
Original article
La version initiale de cet article a été rédigée par Tim Schmid, Raphaël Charles, Jeremias Niggli et Daniel Böhler.
