What is compaction? 

When you look across your field, you might see a uniform, green crop. However, the view from above may not reflect that same thing. Soil compaction isn’t always visible to the naked eye, and damage can go unnoticed, despite plants struggling underground. In some cases, compaction can be detrimental, while in others, it’s more manageable. Compaction occurs when the pore space between soil particles is reduced, affecting the movement of air and water within the soil. As the particles are squeezed together, there is less space for air and water, also limiting the ability of plant roots to penetrate and access the necessary nutrients needed to survive. 

How agriculture influences compaction? 

Compaction most commonly occurs in the spring, when time is tight, and the conditions may not necessarily be ‘fit’ for fieldwork. Additionally, the size of modern equipment has drastically increased, putting more pressure on the soil and increasing the risk of compaction. As everyone is eager to get seed in the ground, sometimes the soil’s ability to support these activities gets overlooked, leading to poor conditions for those early planted crops. Another factor contributing to compaction is the shift from having livestock on the land to more machinery and annual crops. Changes in crop rotation also play a role, as less perennials are planted, which means less organic matter inputs, as well as fewer acres receiving manure which are all beneficial for reducing compaction.  

How compaction influences soil health and crop success? 

Soil compaction not only affects the physical properties of soil but also influences several other characteristics. With tighter pores space, there is less room available for water to infiltrate leading to potential drainage issues. As a result, water availability for growing crops is likely to be reduced. Nutrients that depend on water for distribution such as nitrogen or phosphorus, can become limited in water reduced environments. Additionally, compaction makes it harder for roots to penetrate, causing them to remain shallow and spread horizontally, rather than growing vertically. All these compaction-related issues can cause a reduction in yields. These influences leave the crop at a disadvantage health wise and allow them to be more susceptible to diseases and insect pressure.  
 

How to manage it 

There are just as many ways to manage soil compaction as there are to create it. Like many things, alleviating soil compaction is a long-term process that can’t be solved within a single season. The first step is to assess how deep and where the compaction starts in the soil profile. Using a probe or shovel can help determine how close to the surface the compacted layer is. Examining a plant's roots can also provide some insight into the depth that is actually suited for growth. From an equipment standpoint, it is crucial to be out when conditions are ‘fit’ and fully dry to minimize the risk of compaction. Reducing the weight and using larger, wider tires with appropriate air pressure to distribute the load can make a significant difference. Managing traffic to a controlled flow and having specific lanes helps to limit compaction across the entire field. Soil disturbance methods like strip or deep tillage, which can break up compacted soils. On the crop side of things, incorporating longer crop rotations, cover crops and perennials can help break up compacted soil. Different crops, with different root systems, can help to loosen the soil.  Adding organic matter, through crop residue or manure can resist compaction and stabilize soil structure. Keep in mind that there is not one correct solution when attempting to alleviate compaction but tailoring your approach to suit your operation will often have the best results.