When fertiliser prices rise sharply, the nutrients already present in soil become more valuable. An Irish article sponsored by Grassland Agro argues that farmers can improve nitrogen use by managing the soil as a chemical, physical and biological system rather than treating fertiliser rate as the only variable.
Three parts of soil fertility
Chemical condition includes pH and the balance of nutrients available to plants. On many Irish grassland soils, the article recommends a pH around 6.3 to 6.5, subject to soil type and crop advice. Physical condition determines whether roots can explore the profile and whether air and water move through it. Biological activity helps decompose organic matter and release nitrogen, phosphorus and sulphur.
These parts interact. Poor structure can restrict rooting even when a soil test shows adequate nutrients. Unfavourable pH can reduce availability. Compaction, waterlogging and long periods without living roots can limit biological processes.
Treat product claims as hypotheses to test
The sponsored article cites estimates of substantial potentially mineralisable nitrogen in grassland soils and reports commercial on-farm trials of a soil conditioner. Those figures are useful prompts for investigation, but they should not be treated as a guaranteed saving. Mineralisation changes with temperature, moisture, organic matter, soil type and management.
The reliable starting point is soil testing, field history and observation. Correct pH where needed, protect structure, avoid traffic on wet soil and use nutrient budgets that account for manure and organic matter. If testing a commercial product, leave an untreated comparison and measure yield, forage quality and total nutrient cost over more than one season.
Healthy nutrient cycling can reduce waste and improve resilience. Independent evidence and farm-scale measurement are what turn that principle into a sound business decision.
Read the original Southern Star article, The answer to high fertiliser prices is under our feet.