Increasing Seeding Rates in Cereals
When it comes to seeding I often find alot of growers who consistently seed their wheat or durum at 75lbs/ac, or somewhere in that range. This may achieve a decent plant stand, but opens you up to a few factors as I will discuss later. Plant stand density achieved through a seed rate like that is going to depend on several factors such soil temperature, whether the seed is treated, depth etc. What should be happening is growers are sending away their seed for a seed test to get levels of disease as well as their, germ, vigor and thousand kernel weight. What you can do with this information is plug it into this thousand kernel weight formula ((lb/ac) = desired plant population/ft² x 1,000 K wt. (g) ÷ seedling survival rate (in decimal form such as 0.90) ÷ 10.4) and play around with your target plant stand density to get an accurate seeding rate. What I want to talk about today are some of the benefits of targeting an increased plant stand density of something like 28-35plants/ft2 vs targeting 20-24plants/ft2.
The first thing I like about a higher seeding rate is the "insurance" type aspect. With wireworms levels climbing in alot of areas across the prairies and suppression options that need them to feed on 1-2, even 3 seeds before it knocks them out, you can still lose a significant percentage of your stand in some situations. If you target 32 plants per foot square then you can afford to lose a couple plants in a foot squared area, where as if you only have 20 plants to begin with, you are losing yield potential.
The next benefit is increased weed competition. This allows your crop to choke out weeds vs. it being the other way around. A vigorous stand with more plants is going to more efficiently cover that ground and out compete weeds. This is even more helpful if you are held up a few days or more at in crop herbicide timing.
This increased competition is evident within the crop itself as well. More plants forces them to actively scavenge for nutrients and water, and this forces them to grow at a faster rate to capture sunlight. What this means is that you are pushing your crop along at a faster rate, decreasing time to maturity. I had a producer in my area this year do a trial where he seeded at the rate he normally did (85lbs/ac) and then do part where he seeded at about 130lbs/ac. The maturity difference was about 6 days. This could be huge in years with an early frost or years where seeding is pushed back late.
Increased plant stands typically show increased stage uniformity across the field. The reason for this is that when you have a lower stand, you increase tillering. Sometimes tillering is inconsistent and it takes an extra 3 days or so (give or take a day) for extra tillers to develop. If you have areas of the field producing an extra tiller that puts your staging difference at around 3-4 days. Doesnt sound like much, but all of a sudden you are looking at spraying for fusarium head blight and this can significantly affect efficacy because of the off timing in parts of the field.
I just touched on fusarium head blight and another area that increased seeding rates help with quality and length of time susceptible to stresses such as insects or disease. If you have increased tillering (say 1 main stem, 4 tillers) that means you have an increased length of time that your crop is in anthesis and therefore susceptible to wheat midge, ergot or FHB. If you only have 2 tillers, then that decreases your length of susceptibility by atleast 5 days or so (compared to 4 tillers).
On top of this you typically get 50% of yield from your main stem, and 25% of yield from each of the next 2 tillers. This adds up to 100% of yield potential. Are you willing to lose quality for zero gain in yield? To put even more emphasis on this, why would you want your crop uptaking more nutrients to put into a 4th tiller when you arent gaining from it? It is a waste of energy for the plant.
There has been wetter years recently and more plants does help in cases of excessive moisture. Under drought conditions is the only time where you may see a negative drawback on higher density levels.
Some may have good luck with low seeding rates (I was in a durum field seeded at 45lbs/ac this year, 6 tillers per plant), but I would highly reccommend giving a high seeding rate a try on atleast one field. I talked about my trial earlier and this grower will be seeding everything heavier in 2013. It is a reletively inexpensive investment per acre and has some real benefits.
Saturday, 27 October 2012
Soybeans have been getting a lot of hype over the past couple months with acres in western Canada estimated to rise significantly for 2013. Soybeans are one of my favorite crops to deal with ever since I worked with some my first couple years of scouting. Soys do have significant upside for return, especially with the prices, but I want to talk about some things that seem to fly by the way side when I hear about soybeans lately.
We all know the benefits of soys in Saskatchewan for example, low disease pressure, lower input costs than canola, Roundup Ready trait, rotational benefits and the list goes on.
But we have to remember that breeding varieties suited to our Saskatchewan and Alberta areas is relatively new, and there still isn’t any really short season varieties. Our shortest varities are sitting in the 2325-2350 Heat Unit (CHU’s) range. Generally speaking, there are some areas across Saskatchewan and Alberta that receive these sorts of numbers, but remember these aren’t CHU’s from May 1st, they are from May 15-25, once soil temperatures are in that 12-18 degree Celsius range! Now there will be some variation in varieties due to day length and other specialized traits some varieties have, but overall you want to get as close to those CHU’s as possible to achieve maturity with a decent yield. You would still get some yield if you only got 2150CHU’s for example, but the yield would be reduced along with the quality.
Soybeans will use a good amount of water under ideal conditions, and aren’t deep rooters so scavenging for water is limited. The other consideration is that their peak water use occurs at later flower-pod development sort of time frame, for Saskatchewan and Alberta growers this is going to fall in that late July-early August time frame, which happens to be a typical dry time for us. The negative if we do happen to get a rainier than normal July is that could mean cool, damp conditions which aren’t what we want for our soybeans to reach physiological maturity.
Soybean price is influenced in part by the USA, as we all know. Their drought is the main contributor to the large price jump of soybeans that sparked the increased interest in non-typical growing areas such as Saskatchewan and Alberta. We can’t be sure that the prices for soybeans are going to be as strong as they are now. The first reason being the largest ever seeded soybean acerage in South America (Brazil) and the forecast for good growing conditions (it is still early and a couple more months will tell how the weather affects them). This could significantly affect the price and bring it back down well below $15/bu. The other thing often forgot about is that the Americans will still be putting in another soybean crop around the same time as ours will be going in. The size of their acerage as well as conditions are ultimately going to play a role in where the price goes. Not that it’s a surprise to be a slave to the markets, but in talking with guys one thing that sparked interest in soybeans was the price. If large crops come off in S. America and the USA in the next 12 months then soybeans may be closer to $10/bu than 20$bu, and all of a sudden that 25 bushel an acre bean crop (which would be a high end average for a 2100 CHU, average moisture year, growing area) isn’t as profitable as once thought. Plus the risk of that early frost taking out a large chunk of your yield is always there.
I do believe that once the breeding is farther along and we can knock another 100-200CHU’s (or more) off of the shortest season varieties without sacrificing much yield we can grow soybeans with a consistent profit. There are even some areas across Saskatchewan and Alberta that can grow soybeans right now on a consistent basis. I am not trying to scare anyone away from soybeans, just play devils advocate to all the hype. I do hope producers still try some soys, but on a 20, 40, maybe 80 acre basis to start vs. an entire section. Trying small acreage now can get you the experience with them and develop a comfort level with producing them that allows you to be successful soybean grower once some shorter season varieties, more suited to your area are released.
Monday, 8 October 2012
When I first started working in the agriculture industry I spent my entire month of May blending fertilizer. At this point in time when a grower came in and asked for a “34-17-0” blend, I was a pretty happy guy. It meant effort and less chance of screwing up, win-win for me as an 18 year old trying to make a few bucks in my first summer job. Now a days when someone asks for that blend, I cringe.
Plants need numerous nutrients for proper health and development, some being required, others being beneficial. All of these nutrients are important, but macro nutrients tend to be the ones needed in the largest quantity. These nutrients include nitrogen, phosphorous, potassium and sulfur (and calcium and magnesium depending who you talk to). I want to focus on the importance of sulfur today.
Having a proper fertility package is one of the most important things when starting off your crop in the spring, but it is very often overlooked. I like to put it into terms of us as people, we have 3 essential macro nutrients being protein, carbohydrates and fat. If we were only to eat carbohydrates and proteins, we would begin to run into a whole world of problems due to malnutrition from lack of fat. This occurs with plants as well, even if we don’t see obvious deficiency symptoms, the plants are still weaker and losing yield because of it. Leipigs Law of the minimum shows us that a plant/crop can only produce as much its most limiting factor will allow it. If we only have sulfur in the soil for 30 bushels of wheat, you will be hard pressed to get any more out of that crop due to the lack of sulfur. Sulfur has some key benefits in plants, including being a component of amino acids and enzymes.
Canola is the first crop I would like to touch on why it is important. Many are aware of this due to its promotions by groups such as the Canola Council and many agronomists. What is often left out is why is canola such a heavy user of sulfur? Many growers never ask, and a lot of individuals that promote sulfur don’t really know the specifics behind why canola needs so much. This isnt going to get technical, just some basics and the basics come down to the plant family canola is a part of, Brassicaceae. This family of plant also includes mustards and even vegetables like cabbage and cauliflower. This family of plants has secondary metabolism compounds known as glucosinolates. These compounds are made up mainly of sulfur. The main reason these compounds are important is due to their ability to increase a plants defense system/stress tolerance against pathogens or insects. If we under fertilize sulfur on a canola crop, these compounds begin to be broken down by an enzyme so the plant can use the sulfur else where in the plant, meaning the plants defense system is taking a back seat to other basic physiological processes. This can open your crop up to increase disease or insect risk and increased susceptibility to stresses such as heat. Sulfur is also a component of phytoalexins which are part of the systemic acquired resistance of a plant, or part of its natural defense system There is more that sulfur does in canola as well, but this is the quick and dirty version. Remember, ratio’s of nitrogen to sulfur are important as well. 5:1 (N:S) being the range you want to be in simply because for every 5 lbs of N your crop is going to use 1 pound of S under ideal conditions to achieve the yield you want.
Wheat is often overlooked even more so than canola when it comes to sulfur fertilization. Again, understanding the importance of sulfur in wheat is important. I stated earlier that sulfur is important in amino acids within plants, amino acids are constitutes of proteins and usually a higher protein in wheat means a higher premium. The most common practice to increase protein in wheat is with a late N application, which is fine and consistently works. But since we know protein in a plant isnt made up of only nitrogen, but sulfur as well we can see that sulfur may be the magic trick to bumping yield a bit along with protein. Ratio’s for wheat of N:S are ideally in the 7:1 range.
Lastly, I want to note the importance of sulfur in pulses. All to often I run into growers who don’t fertilize their pulses at all, then there are a few that put down phosphorous, but consistently the few I deal with who put down a full, balanced nutrient package with their pulses have the highest pulse yields. Pulses are high in protein, and as just said with the cereal section, sulfur is a key component of proteins within the plant. The reason many individuals aren’t aware of is its role in activating enzymes that are important for nodulation and nitrogen fixation. Being able to more efficiently fix nitrogen, especially once plants get to flowering when pulses are really needing N and the plant isnt focusing as much on rooting or nodulation can be that extra few bushels of yield you are looking for.
To calculate a range of sulfur your crop will need here are some uptake numbers:
0.25lbs of sulfur/bushel of wheat
0.6lbs of sulfur/bushel of canola
0.25lbs of sulfur/bushel of peas
0.13lbs of sulfur/bushel of lentils
Simply put if you want a 100 bushel wheat crop, your crop is going to need about 25lbs of sulfur per acre (100 bushels * 0.25lbs/bushel/ac)
Remember to keep sulfur in mind when doing your fertility planning for next year.
Going to try and focus a little more on some nutrient importance over the winter when writing as I feel this is the area where many growers could get major yield bumps from. Properly balancing your macro's and then going in and touching on your micro's is a tactic that I think has the most influence on yield, especially in comparison to some like which seed treatment to use. Nutrients each have many roles in the plant, but I want to try and focus on key factors that a nutrient might have in a specific crop.
Note: Try and do a soil test to see where sulfur levels are in your fields and remember sulfur is very mobile in the soil so you may have 7lbs in one spot and 32lbs in another. Also, I am sure you have heard that sulfur comes down with rain and irrigation water, but it is still great practice to monitor levels and try sulfur on your farm if you havent already.
Source: Marschners Mineral Nutrition of Higher Plants