Hasta Eco – Phosphorus balance and resilience based on P-HCl and cultivation system

This report complements previous analyses of pH, nutrient dynamics, and volume-compensated phosphorus. The purpose is to estimate how long the soil's phosphorus reserves can support production without external input, based on P-HCl levels and a biologically active cultivation system.

Assumptions in the system

• Total oat yield: approx. 4 tonnes/ha

• Removal in grain: approx. 3 tonnes/ha

• 1 tonne of biomass + straw returned to the soil

• Intercropping with grey peas (legume) occurs continuously

• Active microbiome and increasing humus contentPhosphorus removal

With a yield of 3 tonnes of grain per hectare, phosphorus removal is estimated at approximately 10–15 kgP/ha/year. Some of the phosphorus in straw and crop residues is returned to the system, which reduces net removal.

System effects influencing the phosphorus balance

• Return of biomass reduces net phosphorus extraction

• Grey peas contribute to biological activity and improved root structure

• Microbial activity mobilizes bound phosphorus

• Improved pH level increases phosphorus availability

• Increased humus content improves retention and circulation

Interpretation of P-HCl (phosphorus reserve)

P-HCl values show that the soil contains significant phosphorus reserves. These reserves can, in a biologically active system, be gradually mobilized and made available to plants.

Sustainability – estimation

Based on observed levels and assumptions about removal and biological mobilization

it is assessed:

• Weaker zones: approx. 5–10 years

• Medium levels: approx. 10–20 years

• Strong zones: 20+ years

This sustainability assumes that:

• Humus content continues to increase or stabilize

• Biological activity is maintained

• The system continues with biomass return

Conclusion

The Hasta Eco-system shows that biologically active agriculture can reduce the need for external phosphorus input for a long time. By combining biomass return, intercropping with legumes, and microbial mobilization of nutrients, the system can maintain a functional phosphorus balance over decades.

What happens over time will be followed up.