C ja NPK calculators

Humus Balance Calculator

The balanced carbon status of soils is gaining increasing attention from agronomic, ecological, and climate perspectives. The term "humus" is widely used in practice, but in laboratory analysis, the actual measurement is the concentration of soil organic carbon (Corg), with humus content being a calculated value derived from it. In this calculator, results are expressed as soil organic carbon (Corg).

The Corg balance primarily depends on production levels, soil type, cultivated crops, and fertilization. A meta-analysis of previous studies was used to develop and refine coefficients and calculation algorithms that take into account the effects of different agro-technologies (tillage methods, solid and liquid manure application, green fertilizers, composts, cover crops, straw management, etc.) on the soil Corg balance.

The calculator can be used on mineral soils to estimate the Corg balance and reserves. Input data required include humus layer thickness, organic carbon concentration, soil texture, crop selection, main yield quantity, and fertilization details. The tool provides results both at the individual field level and as an average for multiple fields or crop rotations.

The program runs on Microsoft Excel and includes macros that must be enabled for proper functionality. The calculator is available for free use and distribution. Significant contributions to its development have been made by Prof. Hugo Roostalu, Associate Professor Enn Lauringson, Prof. Alar Astover, and others.
For feedback and further information: Alar Astover, [email protected]

NPK Field-Based Balance Calculator

This field-based NPK balance calculator is developed based on the principles of a simplified general balance. The output considers the amounts removed with the main and by-products, which depend on yield size and the concentration of the respective nutrients in the harvested crop. Inputs include mineral and organic fertilizers as well as nitrogen fixation by leguminous crops. The time frame for the calculation covers the entire growth cycle of a given crop.

Based on the simplified balance and the proportion of nutrient return (input-output ratio), the calculator provides qualitative verbal assessments of the results, considering specific soil properties and fertilizer requirements for the respective field. Users can modify default values for nitrogen/protein, phosphorus, and potassium content in crop yields, as well as the composition of organic fertilizers and other coefficients as needed.

The program runs on Microsoft Excel and includes macros that must be enabled for proper functionality. The calculator is available for free use and distribution.
For feedback and further information: Alar Astover, [email protected]