When we are seeding peas, we need to ensure that there is at least half an inch of moist soil over the seed. Being a large seed, they require more moisture to germinate and if they are seeded too shallow without good moist soil surrounding the seed, you will get patchy emergence. Some direct seeders who are double shooting say that the draft of the equipment is too great if they are going to seed the peas 2-3 inches deep and the fertilizer knife is running four to 4.5 inches deep. To avoid the heavy draft requirements many are switching the hoses around on their air seeder so the peas go down the bottom opener and the fertilizer is placed to the side. By doing this the peas are placed on a firm, moist seed bed in an optimum growing environment and they haven't sacrificed the seed bed for fertilizer placement.
In 1995 we had very dry conditions in west central and northwest Saskatchewan. The pea yields reported by many farmers were double on direct seeded fields over conventional tilled fields. This was also confirmed by data from Scott Research Station. (Chart #1)
Chart 1
Over the past number of years the same results were found at Indian Head under a variety of moisture conditions. (Chart #2).
Chart 2
The advantage that field peas have under direct seeding are not always expressed in final yield. (Table 1) the height of plant and pods per plant were higher in direct seeded peas at Melfort and Tisdale, however, final yields were similar under both tillage systems. Factors other than tillage systems can be important in determining crop yield, however, the advantage of direct seeded field peas seen at test sites in western Canada provide an opportunity for increased yields when conditions occur for good agronomic performance.
Table 1 Pea Growth Characteristics Under Conventional & Zero Till
Melfort &Tisdale 1994