Compost and Soil Health

Hello! My name is Daniel Vann with UMC,

What is Compost?

Composting is the process of recycling organic materials into an amendment that can be used to enrich soil and plants

Benefits

1. Improves Soil Structure

• Increase soil aggregation and reduces compaction.
• Enhances water infiltration and root penetration—important for deep-rooted almond trees.

2. Increases Water-Holding Capacity

• Compost adds stable organic matter that helps soils retain moisture.
• Important in climates where almonds are grown and water is limited.

3. Slow-Release Nutrients

• Provides a steady supply of N, P, K, and micronutrients over time.
• Reduces nutrient leaching, especially in sandy soils.

4. Enhances Microbial Activity

• Supports soil bacteria and fungi that improve nutrient cycling.
• Encourages mycorrhizal activity (relationship between fungi and plant roots), which helps almonds access water and nutrients more efficiently.

5. Reduces Soil Erosion & Increases Carbon Storage

• Organic matter improves soil stability and contributes to carbon sequestration, which may support sustainability certifications.

Is Compost Worth the Investment in Almond Orchards?

As almond growers continue to weigh rising input costs against long-term orchard performance, compost remains one of the most debated soil amendments. While its benefits are well-recognized, the return on investment varies widely depending on soil conditions, nutrient needs, and pricing.

 

When Compost Is Worth the Money

Orchards with organic matter below 1% see the most benefit (sandy soils). Compost increases soil aggregation, nutrient retention, and biological activity which aid in long-term soil productivity. If you struggle with compaction, slow infiltration, or uneven irrigation distribution, compost can significantly improve water movement and storage in the root zone. Better soil structure often translates directly into higher water-use efficiency. Compost boosts microbial activity, improves root development, and enhances nutrient cycling. These changes support stronger trees and more consistent yields across variable seasons. Compost supplies moderate, slow-release potassium, helping offset fertilizer costs on K-deficient soils—common in many almond-producing regions. The last and most important factor is the price and if nutrient load is worth that price. Being able to calculate nutrient percents out of compost after volatilization is crucial in determining how many lbs of each nutrient you could potentially see in your orchard this season and following seasons to come.

 

When Compost Is Not Worth the Money

Compost is one of the most expensive sources of nitrogen. If N is your primary need in your orchard I would recommend going with manure or synthetic fertilizers since they are more efficient and cost-effective. If your soils have strong structure, 2–3% organic matter, and steady infiltration, the marginal benefits of compost may be too small to justify the expense. In areas with long hauls or high demand, compost prices may push ROI into negative territory. So economic benefits rely heavily on delivered cost per ton. Many orchards already carry elevated K levels. Adding compost in these cases can create nutrient imbalances in the tree particularly by suppressing magnesium and calcium uptake. We have been seeing this mainly in younger trees where the older blocks were chipped back in creating high K levels and low Magnesium levels. Compost can be a high-value investment for almond growers facing soil structure constraints, water efficiency challenges, or long-term soil health goals. However, it is not a universal solution and for nutrient specific needs or already healthy soils, other amendments would offer much better returns. Understanding where your orchard sits on this spectrum is essential for making precise and profitable decisions. See attached spreadsheet with the comparison of buying inorganic nutrition compared to what is received from compost per ton. (not counting the value of organic matter feeding the biological diversity of the soil) Reach out today to any of the contacts below to see how compost can make or break your orchard!

 

 

Compost vs Inorganic Fertilizer Cost Comparison