Kaskiw: Phosphorous deficiency and forage insurance
- Details
- Published on Thursday, March 27, 2014
By: Elmer Kaskiw
myWestman.ca
At the recent Soil Fertility Workshop held in Rivers there was a lot of discussion surrounding the shrinking phosphate levels in our soil. Historically, applications of phosphate fertilizer closely matched removal rates of phosphate by the crop.
Rotations consisted of canola in a one in four or one in three year rotation. The shortfalls in P during the production of canola were compensated for by the higher P rates being applied in the cereal portion of the rotation.
Cropping patterns in Manitoba are changing however and we are now seeing canola being grown every other year and most recently the introduction of soybeans as an alternative to canola and cereals in the rotation.
Soybeans are also high users of phosphate and sensitive to seed placed phosphate. They also respond poorly to phosphate applications in the year of production preferring instead to access or scavenge residual phosphate bound or tied up from previous P applications. Both canola and soybeans with yields in the 40 bushel range will experience a net deficit of between 20-22 pounds per acre of soil phosphate.
So how does one manage this ongoing loss of phosphate in the soil if both canola and soybeans are to be grown as important components of a three to four year rotation with a cereal? Most crops will only recover somewhere between 10 to 30 per cent of the applied organic P during the year of application.
The remainder combines or is tied up by calcium and iron ions to form compounds that are less available to plants. This bound phosphorus is then slowly released over time to subsequent crops. Crops such as soybeans and flax are mycorrhizal crops and are particularly efficient in mining this phosphate and actually respond poorly to applied organic P.
The phosphorus strategy for these mycorrhizal crops is to first feed the soil and then have the soil feed the crop. This means a front loading of phosphorus is necessary in the cereal component of the rotation where larger amounts of organic P can be applied safely with the seed. Ideally we would like to maintain a soil test P level of around 15 to 20 ppm which would equate to around 30 to 40 pounds of actual P.
Once soils are depleted it takes approximately 15 to 30 pounds of actual P over crop removal to raise soil test P levels by 1 ppm. In some cases, where soil P levels are low and canola or soybeans are being grown every other year, it may be necessary to actually band or broadcast phosphate fertilizer in the soybean production year just to maintain phosphorus levels at acceptable levels. This is actually a common recommendation in the US where we see soybean, corn, soybean rotations.
MASC Forage Insurance Reminder
Under the new Forage Insurance program, producers can choose between Select Hay Insurance and Basic Hay Insurance. Select Hay Insurance is intended for producers who want maximum insurance protection for their forages. This insurance offers production and quality guarantees for five types of hay – alfalfa, alfalfa/grass mixtures, tame grasses, sweet clover and coarse hay – on an individual basis.
Producers can insure each hay type individually at 70 per cent or 80 per cent coverage, with coverage now based on an Individual Coverage method that is responsive to a producer’s individual production history.
Basic Hay Insurance provides a whole-farm approach to insuring winter feed supplies against losses at a lower cost. Insurance is offered on the same five hay types as Select Hay Insurance however, for claim purposes, all hay types are used to produce a combined aggregate yield and losses are determined over the entire insured acreage.
Coverage for production shortfalls is included, but to keep premium costs low, there is no quality guarantee. One coverage level of 80 per cent is available, with an option to select a low dollar value or high dollar value. Deadline for application is March 31st. For further information or an individual consultation feel free to contact your local MASC Insurance office .
