Plateauing field pea yields have prompted researchers to study how inputs can help. You can’t use everything — get the best bank for your input buck
Researchers want to figure out which inputs, and combinations of inputs, produce the highest field pea yields in different areas of Saskatchewan, says Anne Kirk.
Kirk is the research manager at the Western Applied Research Corporation (WARC). The research corporation is running a three-year study, funded by the Saskatchewan Pulse Growers, at Scott, Melfort, Swift Current and Indian Head, Saskatchewan.
“We know that there are a lot of instances where producers know which inputs would be the best inputs to apply. But you obviously can’t apply everything in every year. So if you only have a certain amount of money to spend on that pea crop, what’s your best bet?”
Researchers seeded CDC Meadow for each treatment at each site. In the “empty” input package, the seeding rate was 60 seeds per square metre, which resulted in 40 to 55 plants per square metre. Seeding rate in the “full” package was 120 seeds per square metre, translating to between 80 and 105 plants. Row spacing was set at 10 inches. Along with the empty and full packages, researchers applied single treatments to the empty input package, and several treatment combinations.
Input effectiveness varied
Kirk cautions that results are preliminary, as 2012 was the first year of the three-year study. Some of the inputs performed differently at each site.
Ideal growing conditions made Scott the high-yielding site in 2012. The soil had good fertility, at about 20 pounds per acre of nitrogen. The full input package yielded about 5,300 kilograms per hectare (4,729 pounds per acre), while the empty input package yielded about 2,200 kg/ha (1,964 lb./ac.).
“This does show that we do have a great ability to impact field pea yield with inputs,” says Kirk.
Based on statistical analysis of the yields resulting from different combinations of treatments in several plots, researchers were able to estimate how each treatment impacted yield at each location.
At Scott, the higher seeding rate bumped yield by 1,268 kg/ha, as compared with the lower seeding rate. The granular inoculant lifted yield by 902 kg/ha over the liquid formulation. Kirk says the field did have a history of field pea production, so researchers were surprised to see such a jump from the granular inoculant.
When researchers examined the difference between the full input package minus two inputs, some interesting results showed up. For example, removing or adding only starter fertilizer didn’t make a huge difference in yield. But when both starter fertilizer and granular inoculant were removed from the full input package, there was a yield decrease of 1,862 kg/ha. Removing fungicide and starter fertilizer dropped yield by 1,378 kg/ha.
It’s too early to say exactly what these results mean. But Kirk says “protecting yield using these inputs may be more important than we thought.”
Different factors in different area
At Swift Current, the higher seeding rate made the most difference to yields. But fungicides were the main driver at Indian Head and Melfort
Swift Current was a lower yielding site in 2012. The empty package yielded about 1,100 kg/ha (981 lbs./ha); the full package yielded just over 1,600 kg/ha (1,428 lbs./ac.). Higher seeding rates drove yield at Swift Current, accounting for a 506 kilogram per hectare increase over fields with lower seeding rates.
At both Indian Head and Melfort, disease pressure made foliar fungicide vital. Fungicide bolstered yield by 845 kg/ha at Indian Head, and by 1,134 kg/ha at Melfort.
Melfort’s field peas also got a boost of 357 kilograms per hectare from granular inoculant. Higher seeding rates shored up yield by 598 kilograms per hectare at Melfort. Indian Head was the only site that didn’t see a significant increase from higher seeding rates.
“We didn’t expect to see that much of a yield increase from increasing the seeding rate from 60 to 120 seeds per metre squared,” says Kirk.
“Maybe we should be doing more research on seeding rate in field peas to look and see if there could be an even greater yield benefit if we do increase the seeding rate a bit more, because this is something that is relatively easy to control.”
Kirk hopes that the next two years of research will give more definitive answers on the how different input combinations affect yield, and which give farmers the most bang for their buck.
“It is important to look at the yield. It’s also important to look at the economics.” †