Diversity is key in all cropping systems, but have you ever explored what having forages in your grain crop rotation can do?
Endless Benefits
Forages, especially perennial forages, can help alleviate many common annual cropping problems such as soil erosion and soil infertility. Generally, forage crops require less inputs than grain crops, but in return also provide numerous benefits to your future grain crops:
- increased soil fertility, especially when legumes are used
- increased soil quality and better water filtration
- reduction in disease pressure
- reduced weed populations
- greater and deeper carbon sequestering for greenhouse gas reduction.
- increased yields and economics in subsequent crops
Soil Fertility
On years where nitrogen fertilizer costs are high, having a forage crop can greatly reduce the rates needed if not help to generate large amounts of nitrogen within the soil for future crops.
Manitoba Agricultural shares some facts on the nitrogen contributions by alfalfa:
- Average annual contribution of nitrogen by alfalfa is 45 lb/ac but can be as high as 107 lb/ac during optimum growing conditions.
- Research trials show that soil N levels increased by a total of 130 lb/ac after 2 years of alfalfa, when two cuts were taken each year.
- A 5-year alfalfa stand can provide considerable nitrogen for 2 following crops, and nitrogen benefits can last for up to 7 years. In fact, a recent survey showed that cereal crops immediately following alfalfa require little added nitrogen and one-third of the average amount in the second year
When using perennial forage, the soil carbon stock and plant biomass is maximized and extends deeper into the soil. If forage crops are grazed off there is a clear nutrient benefit with the use of manure from livestock. The larger rooting systems of perennial forages can store up to 2.7 times more carbon than grain crops by sequestering it deeper into the soil, helping with the overall reduction in greenhouse gas emissions.
Increased Yield and Quality
Grain crop yields increase after forage crops for many reasons:
- Forages typically enhance the soil nitrogen supply and improve the overall physical condition of the soil, leading to healthier soil and water infiltration to be utilized in future crops.
- There can be a reduction in field weed pressure, due to longer crop cover and how competitive forages can be. This can help to reduce herbicide resistant weed populations. When forage crops are terminated with herbicide this allows for a slower release of nitrogen and helps clean up the few weeds that may have been established.
- Reduction in plant diseases creates the potential for higher yields. Throwing different forage species into rotation helps to break the green bridge between common plant diseases, especially those that are stubble and soil inoculum based. Some species are susceptible to the same plant diseases; would need to watch certain grass species followed by cereal crops, and certain brassica forages followed by canola.
Research out of the Red River Valley looking at alfalfa/wheat rotation versus consecutive wheat rotation found an 18 bu/ac increase of wheat in the first year out of alfalfa and a 2% increase in wheat protein.
Research out of northern Saskatchewan found that growing forage legumes for two years in rotation generally improve grain yield and phosphorus uptake of subsequently grown wheat and canola crops in the Black and Dark-Gray soil zones.
The benefits of forage crops in rotation may not always be immediate or easy to quantify. It’s a long-term approach that helps increase profitability and sustainability on farm.
Contact your local RAM today to discuss adding forage crops to your rotation.
