The Manure Spreading Advisory Committee (consisting of industry and government representatives) is advising against manure applications due to lower air temperatures, the increased potential of significant rain events, and lack of vegetative cover and/or reduced nutrient uptake of cover crops. The committee will monitor weather and soil conditions and will issue further advisories as conditions change. Principal environmental risks associated with manure application:
For the past two years, significant rainfall started by mid-October in the Fraser Valley, above the long term average (see Figure 1 below). Forecasts may provide some indication as to what can be expected this year, better to plan and be prepared in advance of the rainy season when manure applications are not recommended.
Date: September 1, 2018
- Perennial grasses continue to benefit from fall manure applications when applied to meet crop nutrient needs.
- Manure applications for cover crops and newly seeded grasses should be based on a soil test and only applied if the cover crop will become well established to uptake nutrients prior to the end of the growing season. Manure applications on harvested or fallow fields are not recommended.
Considerations for spreading manure during warm weather: When spreading manure during the summer, it is important to consider the impact of high temperatures on nitrogen (N) loss from manure. Volatilization of ammonia during and shortly after application is greatly increased when temperatures are high. Several other factors including manure composition, time to incorporation, wind, soil pH and moisture, and application method will impact ammonia loss as well. Losing ammonia from manure is a direct loss of its fertilizer value and should be considered when planning application timing and calculating manure’s contribution to crop N requirements. Spreading manure when temperatures are above 25°C can result in a loss of 50% of the ammonia N within three hours of application.