Back-to-Basics: Regional Updates Archive

As spring approaches, soil conditions are wet in many areas. A wet fall kept many farmers out of the field and some people opted to skip P and K applications then. Spring is going to be a mad rush to get both fall and spring tasks completed. There is a good chance that the P and K that were skipped in the fall will be skipped again in the spring – again to save time. Combined with P and K omissions in the last couple years due to higher nutrient prices, many areas are in need of a soil fertility reassessment. Plans should be made now for spring or fall soil sampling, whichever is consistent with past sampling times. Watching crop development and looking for visible signs of nutrient deficiencies is also recommended to add to the information used in decision making.

Consequences of the Past Two Years

Price fluctuations in the past 2 years led many producers to reduce nutrient applications, particularly for K. What happened to the balance between the amount applied and the amount removed? For Eastern Canada, the balance trends show that the K in the fertilizer and manure that was applied amounted to only half the amount removed in crop harvest. The crop nutrient balance in the Lake Erie Watershed has also shifted.

What are the consequences? The International Plant Nutrition Institute offers several new information sources that sort through the issues and help you improve the use efficiency of plant nutrients. Check out the following:

How To Choose An Enhanced-Efficiency Fertilizer
What Are the Consequences of Not Maintaining Soil Potassium?

20-24 June 2010 — Joint Annual Meeting of the Canadian Society of Agronomy and the Canadian Society of Soil Science. University of Saskatchewan, Saskatoon, SK.
27-30 June 2010 — ASA-CSSA-SSSA Northeastern Branch Meeting, Cornell University, Ithaca, NY.
18-21 July 2010 — The 10th International Conference on Precision Agriculture – Hyatt Regency Tech Center, Denver, CO.

Don’t Forget the Benefits of Diversified Crop Rotations

One of the reasons we are able to grow crops successfully in the Northern Great Plains is that many of the farmers have diversified crop rotations. By this I mean that rather than just growing a monoculture of one type of crop, e.g. continuous wheat, wheat is rotated with other crops. For example, in central Saskatchewan a common 4-year rotation can be wheat-canola-barley-lentils. The advantage of this type of rotation is that there are alternating years of a small grain cereal crop with years of a broadleaf crop. This helps control weeds, crop diseases, insect pests, and also allows a grower to have a diverse suite of crops to market. Chances are if wheat prices are down canola or lentil prices may be on the upside.

Market prices for various crops are always going to go up and down, but I find it a concern when growers ask what I think about them changing their crop rotation drastically and growing significantly more of one crop in their rotation in any one year. For example, this winter one grower asked what I think of them growing much more canola than they normally do. For example, rather than one-quarter of the cropped acres in canola, to plant all the land to canola with no wheat, lentils, or barley. My first reaction is to ask “Are you sure that is a good idea?” I realize that canola prices are better relative to wheat and barley right now, but putting all farm resources into one crop increases risk, also.

The subsequent crop yield increase from changing crops in rotation is well documented. For example, in a 9-year cropping study in north-central Alberta the yield of canola was looked at comparing yields after different preceding crops. The lowest yield was canola after canola, and the highest was canola after barley.

Table 1. Relative canola yield as affected by previous crop, 1992 to 1998 study, Alberta.

Source: 2003, M. Hartman, Oilseed Specialist, Alberta Agriculture and Rural Development, Olds, AB

When I worked as a regional retail agronomist during the years 2003 through 2007 in south-central Alberta, I remember a farm customer east of Calgary, that wanted to try growing canola after canola on one field and compare the yield to canola after wheat in their normal 3-year wheat-canola-barley rotation. If this strategy worked they were considering going to a 4-year rotation of wheat-canola-canola-barley. The result from the one year comparison was that the canola yielded about 25% less (35 bu/A compared to 45 bu/A) when seeded on canola stubble compared to canola seeded on wheat stubble. Their going-forward strategy was to maintain their 3-year rotation and not try to increase the amount of canola in their crop rotation.

I realize that every area in the Northern Great Plains has a different set of crop rotations, and there are usually good reasons why one rotation is used in a specific area. For example, in the very dry areas of south-east Alberta and eastern Montana a common rotation is spring wheat-summerfallow, with wheat in that rotation sometimes being substituted by barley, or winter wheat, or even mustard. The main reason for summerfallowing is to conserve soil moisture, as during dry periods it is more profitable to get a reasonable yielding crop every other year than suffering a crop failure 4 out of 10 years if summer-fallowing isn’t used. Summerfallow-wheat isn’t really a crop rotation, but it is a cropping system rotation based on water conservation requirements in dry years.

However, in areas where there is sufficient moisture to have continuous cropping, I think the benefits of having a crop rotation outweighs the short-term marketing benefits of shifting a majority of the fields to one crop type, even in the short-term (one to 2 years), and especially in the longer-term (3 or more years).

Early-spring conditions throughout much of the Southeast have been cool and wet. Some states are reporting weather trends markedly different than normal. In Georgia, for example, soil temperatures during corn planting have been 5 to 9 degrees lower than the 3-yr average. These cool temperatures result in a very slow developing crop, but with all the rain this season, some growers are willing to accept the risk of planting into cold soils just to get the crop into the ground. Reports of corn being planted despite low soil temperatures are also coming out of Arkansas and Mississippi. Wet conditions are keeping farmers out of the field in South Carolina, but that shouldn’t have much of an impact on the 2010 crop. Clemson corn and soybean specialist Dr. Pawel Wiatrak said, "It's still wet in many parts of the state, and things continue to move slowly in many places. Our normal recommended planting dates are between March 20 and April 20, so we're not behind. But many farmers do prefer starting early, and all these delays are very frustrating for them." The Florida panhandle is wet also; however, they are reporting corn planting and other spring fieldwork to be 2.5 to 3 weeks behind schedule due to weather.

One practice that growers who are determined to plant into cold soils can consider is a starter fertilizer application. No-till corn studies conducted in west Tennessee demonstrated that starter N fertilizers applied in-furrow over a 3-yr period increased grain yields an average of 10 bu/A. However, Dr. Don Howard, the soil fertility researcher who conducted the work, cautioned against expecting a response every year. “In general, starter fertilizers provide a yield response when soils are cold. That's when you want to use a starter. You can push that window of planting time just a little earlier than you normally would. Once you get on up into the planting season and soils begin to warm up, you should eliminate that starter fertilizer because it probably will not work as efficiently as it did earlier in the year.” Work out of Louisiana also showed that low volumes of in-row applied 10-34-0 had the potential to increase corn grain yield and reduce grain moisture at harvest.

Unseasonably cold, wet weather has also affected the current wheat crop, as well as other small grains in the region. According to the calendar, much of the small grain acreage in the Southeast would have had at least the first N application by now. In some parts of the region, the entire N requirement typically has been applied. However, a wet fall throughout much of the region resulted in late planting, with some oat crops not going in until January. Extended cold periods this spring have further slowed down an already late crop, resulting in many thin and poor looking stands. Spring tillers won’t yield as high as fall tillers, but well fertilized small grain can come on and surprise you. Before abandoning a small grain field for a spring crop, seek advice from a university extension specialist or professional crop consultant. Tiller counts may reveal the crop to be salvageable with a spring N application.

Southern and Central Great Plains Region

The moisture conditions across the region have improved considerably from this time last year. As of this writing (March) most of the region is very moist to excessively moist, with the remainder near normal. All of this points to the potential for an excellent spring and start to the 2010 production season since most areas are starting with a full soil profile. Wheat condition overall is in the fair to excellent range, with very little wheat rated as poor. Some N deficiency has been observed in areas that have had considerable rain or snow. Remember that the wheat crop needs adequate available N as it goes into the spring. In general, wheat takes up about 2.0 to 2.5 lbs N per bushel produced, or if grazed, about one lb for each 3 lb of stocker gain. Adequate N must be available to the crop at all phases of development. Shortages may ultimately result in reduced tillering, reduction in head size, poor grain fill, reduced yields, and low protein content. Splitting N applications has the potential to improve use efficiency, minimize risk, and safeguard the environment. It is critical that topdress applications be made early, prior to jointing, to maximize production efficiency. “Topdress by jointing” is the standard recommendation, but it is probably more accurate to say that N should be available for uptake (i.e., moved into the root zone) by jointing. Source should be managed according to equipment, availability, price and other practical factors. Gaseous loss of N from urea containing fertilizer is not of great concern in wheat topdressing since temperatures are usually below the threshold of concern (50-55oF).

As Spring rolls around, farmers in the West always look at the water supply forecast. The tight water situation that has gripped California for the past several years has eased somewhat, but the water concerns have shifted to the Pacific Northwest. For example, Walla Walla in Washington state has only received 55% of its normal precipitation this past winter. Many farmers who grow irrigated crops depend on the winter snowpack to keep the reservoirs full. The U.S. Drought Monitor reports that the entire state of Idaho and most of Oregon, Washington, Wyoming, and Utah are currently abnormally dry.

Whatever your local condition, consider how you can adapt to make the best use of your available water. Improving irrigation efficiency can dramatically cut pumping and energy costs, reduce fertilizer loss, and increase yields. All this is must be done with an eye for providing adequate water for wildlife and recreation.

Each state provides modern climate monitoring tools to estimate the water needs of crops and to assist with irrigation scheduling. On many farms, irrigation technology has greatly advanced during the past few decades, but attention to irrigation management has not always followed. Contact an irrigation professional or a Certified Crop Adviser to get current information on improving water management practices.

It’s not too late to take soil samples and plan for a plant tissue testing program during the coming season in order to track the crop nutritional status. Maintain your soil in top condition to keep plant roots healthy, giving crops the necessary foundation for top yields.

Although you may see tempting offers for new plant nutrient products that promise wonderful results, remember that no additive will compensate for poor management and inadequate crop nutrition. If you want to try new products, ask about its track record and request performance data on your crops. Start small and test any new products on a portion of the field – including plots that are both treated and untreated.

As the growing season gets underway, let’s make the most of our opportunities in 2010 and put the pieces together to grow a productive and profitable crop!