What is the crop and soil module and what does it do?
The Soil and Crop Module is one of the core biophysical modules in RuFaS. This module simulates the daily changes in soil composition and crop growth based on nutrient availability, weather and soil types. It simulates user-provided management practices including application of manure or synthetic fertilizer, tillage, planting and harvesting. Based on SWAT, Daycent, and SurPhos, RuFaS models the nitrogen cycle (denitrification and nitrification), soil water infiltration, percolation, and saturation leading to runoff, the phosphorus cycle and the carbon cycle (accumulation and decomposition of biomass and soil carbon storage). The Soil and Crop module is connected to the Manure module and will request farm generated manure to be applied to fields when applicable. The Soil and Crop module is also connected to the Feed Storage module to manage inventories of the harvested crops and provide feed to the herd based on availability.
How much data is needed by the crop and soil module?
Soil nutrient composition is integral to proper estimation of crop growth, nutrient cycling, and emissions. RuFaS uses the SSURGO database for soil information, but some of this information is dated and therefore, the more historical data that can be provided, the more accurate the outputs will be. At a minimum, it is requested that one entire crop rotation is provided to RuFaS; if there is not a rotation and one crop is continuously planted, a minimum of 5 years of data must be provided.
Field level data including irrigation, location, and size is needed. Then crop rotation data regarding planting and harvesting dates, dates and quantities of synthetic and manure nutrient applications, and dates and types of tillage events are needed for each field. It is important to have all of this data aggregated before trying to enter it because the RuFaS input parameters will require data entry in inputs that might not match exactly farm provided information (for example, total kg instead of rates) and it is often easiest to complete an entire section (ie manure application schedule) before moving onto another section (ie fertilizer application schedule).
What are the inputs for the crop and soil module?
- Field: location, size, irrigation rates
- Crop rotation: crop and harvest type (ie hay vs grain vs silage), planting and harvest dates, planting order if multiple crops are planted in a year
- Nutrient application: dates, quantities, depth and % remaining on surface, mix or manure type
- Tillage: dates, implement, depth, mixing and incorporation fractions
What are the outputs for the crop and soil module?
- Crop:
- Growth / biomass accumulation
- Harvest yields
- Field:
- Soil carbon stock change
- N2O and CO2 emissions
- Nitrate percolation and phosphorus runoff
- Soil erosion
What is the future of the crop and soil module?
- Harvest intervals being linked to crop digestibility and nutrient makeup: currently, the digestibility of a crop is based on hard coded parameters for each crop type, regardless of growth or harvest interval. Yield is dynamically updated based on how long a crop is being grown and the stress (water, temperature, and nutrient) that the crop is under but in the future, attributes including NDF, CP, and starch will also be dynamically updated based on the crop type, growing conditions, and planting and harvest dates.
- User defined crop attributes: today, a user can adjust the parameters that define how a crop responds to the environment around it (amount of sunlight, temperature, nutrient availability), however, specific guidance for how to adjust these attributes to match the breed or variety planted is not available. In the future, if high oleic soybeans or BMR corn, for example, are purchased and planted by a farmer, the soybean and corn silage crop attribute information can be updated to represent these characteristics.
- User friendly irrigation schedules: irrigation schedules can be defined today through the weather input file or the field input file, however both methods are slightly cumbersome to use. Updates in the future will include the ability to create a schedule that can run at certain times of the year and then be edited at other times of the year.
- Expanded selection of pre-defined crops: today corn (silage and grain), soybean (hay and grain), cereal rye (hay, silage and baleage), tall fescue (hay, silage and baleage), triticale (hay, silage, and baleage), winter wheat (hay, silage, and baleage) and alfalfa (hay, silage and baleage) are available for planting. Additional common crops and the ability to interseed (alfalfa + grass) will be available in the future.
- Combined harvest events: today, a user must choose an individual harvest event for each requested harvest. In some cases, it is common for a grain to be harvested via combine and the stalk harvested as straw. This will be updated in future versions of RuFaS such that multiple harvest types can occur at one time.