Re-Think Your Cereal Seeding Rates – for Jul. 25, 2011

When preparing crop plans with farmers and discussing planned cereal seeding rates, they usually talk in bushels per acre. But using the same rule-of-thumb bushels per acre can mean very different seeding rates year over year. Instead, we start by establishing a target plant stand per square foot for each crop type and perhaps even by field. If we’re not starting with a target in mind, we’re only guessing that a couple of bushels of seed will get us close enough and we are hoping it all fits into our crop budget. A precise plant stand target works into our plan to achieve a targeted yield goal and everything we do with the crop will be focused on maintaining the plant stand required to realize the yield goal.

MATCH SEEDING RATE TO FIELD POTENTIAL

Plant stand recommendations have been established for the Prairies based on averages for each crop and all areas with an average growing season. These recommendations are a starting point and should be a guide, yes, but we all know that averages, by very definition, aren’t very precise. In our business, we do not treat all areas as average, because each field is unique and some have more crop producing potential than others.

Fertilizer rate recommendations are based on yield goals and the field potential. Seeding rates should follow the same criteria. Adjust seeding rate or plant stand density for field conditions not by how many bushels of seed to be seeded but by plants per square foot.

OVER-AND UNDER-SEEDING

By using the actual 1000 kernel weights of seed lots and doing germination tests to check seed quality on different varieties of spring wheat over the last number of years we have seen a range between 100 to 140 pounds per acre required to achieve the same targeted 34 plants per square foot. How’s that, you say? Well, the variety plays a role, but the conditions that the crop was grown in has a huge impact on the plumpness and test weight of the seed. Test weights can change a seeding rate dramatically.

If you’re going to re-evaluate and fine-tune your seeding rates, the first step is to determine the 1000 kernel weight when checking germination levels. The benefits of 1,000 KW are threefold:

1) You may actually be over-seeding. Too much seed is a waste if growing conditions are poor. Too many plants over-compete for moisture and nutrients.

2) You may be sacrificing yield potential by under-seeding. Optimimum seeding rates should result in a uniform crop that matures evenly, and produces fewer tillers with high moisture kernels.

3) Seed treatment accuracy depends on calibrating the treater to the amount of seed based on true seed weights. Seed treatment rates are measured in ml/100 kg of seed. When applying seed treatment to different seed lots the application equipment settings will change as seed test weights change.

PROVE IT

The second recommendation is for farmers to take the time to do some seeding rate trials on their own farm. Determine optimum plant stands for your fields to get experience with how higher or lower plant densities respond to various conditions. Seeding rate trials are easy enough to do by seeding a couple of passes at 80 per cent your standard rate and a couple of passes at 120 per cent of the standard rate. At harvest time, check the yield difference with the combine monitor or a weigh wagon and compare to an adjacent strip of standard rate. Information from on-farm trials is important when recorded and referred to at crop planning time.

Just as we know there are differences across the prairies for ideal seeding rates, there are differences from field to field. With variable rate technology we can seed at the optimum rate within the field. The theory we are following for variable rate seeding is to manage the higher fertility rates with increased seed rates and where the fertilizer rates are lower to also reduce the seeding rates where the yield potential is less.

Improving seeding rates for optimum plant density by seeding with a specific plant population target and will not only save money but increases the probability of determining the plant stands that are specific to your field conditions to help realize yield potential.

JasonCasselmanisapartnerandagronomist

withDunveganAgSolutionsInc.( www.howtogotoagsi.com) atRycroft,Alta.

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