Chemical fertility of soils in arable farming

Fertility management in arable crops / Chemical fertility of soils in arable farming

Arable crops Arable crops

Soil chemical fertility is an important aspect for the productivity of large crops. It is linked to the availability of nutrients for plants and directly influences their health and yield.

Optimizing soil chemical fertility

Chemical fertility depends on several key factors, some of which can be improved by appropriate agricultural practices:

Soil pH management

Soil pH directly influences nutrient availability and soil biological activity. An optimal pH between 6.0 and 6.5 is recommended for most arable crops. In case of excessive acidity, regular application of lime and magnesium amendments helps correct this imbalance and improve fertilizer efficiency.

Cation Exchange Capacity (CEC)

It represents the soil's capacity to retain and exchange cations (Ca²⁺, Mg²⁺, K⁺), essential for plant nutrition. It mainly depends on soil texture and clay content, factors that are hardly modifiable. However, an effective CEC allows better nutrient availability. Although CEC is partly an intrinsic soil characteristic, incorporating organic matter and managing pH enhance its effectiveness.

Organic matter content

Organic matter plays an essential role in soil chemical fertility. It improves nutrient retention, stimulates biological activity, and stabilizes soil structure. Incorporating cover crops, returning crop residues, and using organic waste products increase organic matter content.

Availability of macro and micronutrients

Elements such as nitrogen, phosphorus, potassium, magnesium, and various micronutrients are essential for crop growth. Managing macro and micronutrients (N, P, K, Mg, and micronutrients) is crucial to ensure optimal plant growth. Poorly adjusted fertilization can cause deficiencies or excesses harmful to the environment. Reasoned fertilization can be an effective lever: adapting mineral and organic fertilizer inputs according to crop needs, soil analysis results, and previous crops.

Diversify crops and preserve fertility in the long term

Cultural practices also influence soil chemical fertility. A sustainable approach includes diversification of crops and practices that promote biological activity.

• Crop rotation: Practice long rotations including legumes to improve atmospheric nitrogen fixation and diversify nutrient uptake.
• Use of cover crops: Introduce diverse covers to improve soil structure, trap nitrates, and enrich the soil with carbon and micronutrients.
• Reduced tillage: Adopt minimal tillage practices to preserve soil structure and life, thus promoting better nutrient retention and circulation.

Regular monitoring and practice adjustment

Periodic monitoring allows adapting agricultural practices to soil specifics and crop needs.

Regular soil analyses enable adjusting nutrient inputs and tracking chemical fertility evolution..

By implementing these solutions, farmers can sustainably improve the chemical fertility of their soils, contributing to more productive and environmentally friendly agriculture.

Reducing operating costs through reasoned fertilization

The rise in input and fuel prices was spectacular in 2022. According to annual Agreste reports, over the 2021-2022 period the increase was:

• + 108.3 % for all fertilizers
• + 141.2 % for nitrogen fertilizers
• + 88.6 % for phosphorus fertilizers
• + 106.5 % for potash
• + 74.8 % for non-road diesel

Soil analysis allows to identify soil needs and reduce operating costs by avoiding excessive input purchases. It also enables rethinking fertilization strategy and the agricultural system to move towards a “self-fertile” system based on a well-functioning soil biology.

References

• Soil fertility: optimizing crop yield through nuclear techniques - IAEA (iaea.org)
• Memoir_V.Le Cam.pdf (ecophytopic.fr) [PDF]
• Improving fertility (fertilisation-edu.fr)