Back-to-Basics: Regional Updates Archive

Spring conditions in many parts of the Northcentral region were very wet. Saturated soils delayed planting and N applications in many areas. Additionally, wet conditions have also led to increased chances of losses of N applied last fall or earlier this season, due to denitrification. Farmers are currently grappling with a greater amount of uncertainty about their N programs than under more normal, drier years.

Additionally, many have observed that K soil test levels have been on the decline over the last few years. It is not currently known how extensively this decline is or if it is a real soil fertility decrease or an artefact of weather-induced variability. Fertility levels of K in soils is of key interest as we look at future production trends.

Projected removal of corn stover and other biomass feedstocks into the ethanol industry are expected to remove more K than under current practices. It is not clear, however, just how much more K could be removed. A large part of this uncertainty is the rate at which K is leached from crop vegetative portions after maturity has been reached. Weather conditions, particularly rainfall quantity and intensity, influence K leaching rates considerably. It is also unclear how the biofuel industry will manage such variability in its feedstocks.

Finally, there is renewed interest in how nutrients interact to influence crop yield. This interest has arisen from greater fluctuations in nutrient prices in the past two to three years. Current university recommendation algorithms do not consider nutrient interactions but instead focus on each nutrient individually and assume that other nutrients are in quantities that are not yield limiting. While this single nutrient approach to making recommendations has been effective in increasing yields and creating profits over time, it is not positioned to help farmers allocate limited funds across nutrients when the recommended fertilizer program cannot be afforded. Future recommendation approaches will need to consider nutrient interactions. Examples of such approaches exist in other areas of the world where farmers have been financially restrained for a long time.

Ontario’s 1.9 million acres of corn has probably never been planted earlier, and despite strong frosts on the 9th and 10th of May the crop looks good. Sidedressing time has arrived, and many pre-sidedress soil nitrate tests are coming back higher than average. Cornell University’s weather-based N management tool, Adapt-N, also predicts greater than average amounts of N available from the soil this year, owing to the warm temperatures of April and May. While soil N supplies are high, the potential demand is also high owing to the good start the corn crop has had so far. Ontario corn N recommendations take into account many factors – check out the N Calculator and information on other crops at www.gocorn.net.

Environment Canada predicts warmer-than-average temperatures for most of the Eastern Canada crop production area for the coming summer and fall.

Coming Events:
06/20/2010 - 06/24/2010
Joint Annual Meeting of the Canadian Society of Agronomy and the Canadian Society of Soil Science, University of Saskatchewan, Saskatoon, SK, Canada. more info ...

06/27/2010 - 06/30/2010
ASA-CSSA-SSSA Northeastern Branch Meeting, Cornell University, Ithaca, NY, USA
more info ...

09/12/2010 - 09/17/2010
14th International Conference on Diffuse Pollution, Quebec, QC more info ...

10/27/2010
Communities in Bloom, Halifax, Nova Scotia, Canada
“Nutrient Stewardship for Healthy Lawns”

11/16/2010 - 11/18/2010
TFI-FIRT Fertilizer Outlook and Technology conference, Savannah, GA, USA
Dr. Bruulsema invited to speak on "Managing Plant Nutrition to Sustain Human Health."

11/24/2010 - 11/26/2010
Soil Fertility II - Dealer Education Course, Woodstock, Ontario, Canada
An introduction to the basic concepts of soil fertility and nutrient management.

What happens to soils when higher than average precipitation is received?

It appears that much of the Northern Great Plains (NGP) region is experiencing higher than average spring precipitation this year. For much of the area from north-central Montana, up through to central Alberta, and across to west-central Saskatchewan this is a pleasant change from the droughty conditions in 2009. For example, at Oyen, on the eastern edge of Alberta about 270 km (168 mi) north of the US border the average long-term 30-year average for precipitation between April 1st and May 30th is 53 mm (2.1 in). In 2009, the amount received was 7.5 mm (0.3 in.) or it was very dry.

However this year (2010) the amount received during this period is 116 mm (4.6 in.). This represents more than twice the amount of normal precipitation, and farmers in that area are pleased the so-called drought is over.

Some areas, however, are experiencing even significantly greater than normal precipitation along with very wet soils. In the NGP, especially on the western half, the problem of excessively wet soils isn’t something we often have to concern ourselves with. However, saturated soils do present some challenges for cropping.

Initially, there are delays in planting spring crops because it is impossible to plant crops into excessively wet, or flooded fields. Delayed planting can reduce crop yields even though the moisture situation may be promising. The shortened growing season doesn’t allow crops to develop as high of a yield compared to an earlier planting date. Additionally, the fall-seeded winter wheat crops can suffer from flooding in low areas.

Some low-lying areas of fields will be flooded past the window of time for possible planting. When these areas do dry out later in the growing season weeds and volunteer crops grow. This plant growth will need to be controlled to prevent production of weed seeds for future years. In most cases growers will choose to summer-fallow the area by using non-selective herbicides in a chem-fallow, or will cultivate the area to control plant growth.

If field operations including pre-seeding herbicide applications, tillage operations, fertilizer applications, and planting operations, are done when soils are excessively wet, or as some producers say “mud the crop in”, there is always the potential to have sub-surface soil compaction in the wheel track areas. Compacted soils will cause poor root development of crops in the affected wheel tracks and can reduce crop yields. Depending on equipment design and configuration of the tractor and planter, the area affected by compaction can seem minor, e.g. 10% of the soil surface, but a 50% yield reduction in the wheel track areas could potentially cause an overall 5% yield reduction over the whole field. Another challenge with wheel track compaction is that it can persist for a year or two, and often there are ruts made along with the sub-surface compaction. In severe cases a grower may need to consider sub-surface ripping or sub-soiling along with tillage at the surface after crop harvest in the wheel-track areas, to correct the compaction and the surface ruts. This can be especially annoying for growers using no-till cropping systems, but it is better to deal with the sub-surface compaction and rutting than to leave the fields in rough shape.

If overly wet conditions persist for too long after planting, crop germination and emergence can be reduced due to rotting of some seed due to low oxygen levels in the soil and conditions that are ideal for growth of some fungal root disease organisms. Either way crop stands can be reducing causing lower crop yields.

Wet conditions also increase the chance of losses of applied N fertilizer, whether applied the previous fall or earlier this spring before the heavy rains came. This can be due to leaching of nitrate (NO3-) below the rooting zone of some crops, mostly on sandy-textured soils, and nitrification and or denitrification losses, mostly on the loam or clay-loam textured soils. These nitrification or denitrification losses result in nitrous oxide (N2O) or di-nitrogen (N2) gas emissions. Soil microbes suffer from oxygen shortages when soils are saturated and they use the oxygen from nitrite (NO2-) during the nitrification process (conversion of ammonium-based fertilizer from NH4+ to NO2-, then to NO3-), or from denitrification of NO3- already present. Either way N2O or N2 losses can mean losses of fertilizer N that will not be used by crop plants, and this can be costly to growers. If growing conditions improve later in the growing season there may be need to top-dress additional N fertilizer to meet crop needs, if significant amounts of the previously applied N-fertilizer have been converted over to NO2- or NO3-, and lost under wet conditions.

In the NGP we more often suffer from moisture deficits that restrict crop yields, but there are the occasional years when unusually high precipitation is received resulting in delayed or no planting, poor crop emergence, potential for wheel track sub-surface soil compaction and surface rutting, and gaseous losses of applied fertilizer N due to nitrification and denitrification losses. Admittedly, most of the areas will have reasonably good yielding crops, even though parts of fields may yield poorly due to excessive water. Water is an essential requirement for crop growth, but even a good thing like water can cause problems when too much is received.

Wheat harvest is underway in the southeast region. Most of the crop so far has been in the fair to good category. What really looks good is the rice throughout much of the region. Reports out of Arkansas, Mississippi, Louisiana, and the bootheel of Missouri rate a fourth to a third of the crop as excellent. Mississippi is reporting 25% of their corn and cotton crops to be excellent as well. Throughout the region, the corn and cotton are doing well. There have been a few dry spells here and there, but no major concerns. For the third year in a row, Tennessee’s most productive cotton ground, the TN Delta, will be planted to soybean. Record rainfall in early May resulted in severe flooding in Nashville, which made national news.

Areas across middle and west TN received as much as 22 inches of rain. According to Dr. Chris Main, UT cotton specialist, total estimated loss in cotton due to flooding could reach as high a 60,000 acres. Tennessee is not the only one looking at lower cotton production. The recent supply-demand report from the USDA projected ending stocks to be 2.8 million bales, the lowest since 1995, which could mean good news for growers in terms of price.

As many of you may know, Colorado is hosting the world’s largest and most prestigious Precision Agricultural Conference, the 10th International Conference on Precision Agriculture, at the Hyatt Regency Hotel in the Denver Tech Center, Denver, CO from July 18th – 21rd, 2010.

Topics in the conference: There will be over 500 attendees including scientists, practitioners and industry personnel from over 40 countries around the world. Topics in the conference include but are not limited to:

Keeping with the tradition of the ICPA conferences, there will be concurrent sessions each day of the conference. Among those will be a dedicated session called “A to Z Track” which is meant especially for crop consultants, advisers, agronomists, producers, extension agents, and other practitioners.

The A to Z track will have talks from experts and specialists in their respective disciplines. These specialists will present talks that will be applied in nature with relevant “take home messages” for practitioners and others. We have put together an excellent group of presenters for the A to Z track. The list of speakers and topics can be found on the web at http://icpaonline.org/conferenceprogram/icpa2010. The featured speakers will include university scientists, industry specialists, and growers presenting information relevant for several major crops.

Discounted Registration Fees for Practitioners to attend the A to Z tracks:

For crop consultants, advisers, producers, extension agents and other practitioners, there is a reduced conference registration fee of $300 (full conference registration is $550) to attend the A to Z portion of the conference.

For one day A to Z registration (either Monday July 19st or Tuesday July 20nd): $150/day

Please go to the conference registration website http://www.icpaonline.org/registrationpage/ and choose A to Z track for registration.

Southern and Central Great Plains Region

Moisture conditions across the SCGP region are good for the most part. Abundant spring rain has resulted in adequate to surplus top and sub-soil moisture in most of the region. The June 5 Palmer Drought Index shows that the only area of drought is the eastern part of Texas. The remainder of the region is rated as normal to extremely moist. Thus, when it comes to moisture the region has a good start on the 2010 summer season. This is reflected in the crop conditions reports, where as of the first part of June ratings are mostly good to excellent. Wheat harvest is well underway in the southern reaches of the region, and wheat condition is generally good.

The production of summer forage and hay is critical to the economies of many agricultural systems. Producers should remember that where forage biomass is removed as hay or silage large quantities of nutrients may also be removed (see table for examples). Over time this mining, especially of P and K, can deplete nutrient supplies and result in reduced productivity and profitability. When planning fertilizer needs for hay production this season and into the future it is advisable to take into account nutrient export from fields.

It seems that we are always talking about the water supply in the West. Since an adequate water supply is fundamental to growing crops, the availability of irrigation water continually dominates discussions. Every farmer should be as efficient as possible in the use of this precious production input. This includes checking nozzles, fixing leaks, and maintaining soil moisture at appropriate levels.

A properly managed water supply is essential for getting full value from plant nutrients. Drought conditions keep water and nutrients from entering the root system. Excessive water application damages root systems and can lead to leaching loss of nutrients below the root zone.

It’s a sign of the time when growers in California are happy to receive 40 or 50% of a full irrigation allocation this year. That shows how dry things have been the past several years. The snowpack that supplies water for potato growers in eastern and southern Idaho was near an all-time low this year. Since the dry conditions and water shortages move around the region each year, everyone needs to pay attention to the best use of this scarce resource.

Water management directly impacts two environmental issues developing in California. The state of California will be imposing limits on nitrous oxide emissions from agricultural soils. Nitrous oxide gas partially results from nitrate that remains in very wet soil for several days or more. A water regulatory agency in California is proposing that each farmer have a nutrient management plan in order to reduce impacts on groundwater. The pressure for using water and nutrients more efficiently is growing.

Water is an essential input for crop growth. Water is converted into harvests of the healthy and abundant food supply that many urban dwellers take for granted. But the water supply is limited and we all need to use this resource as carefully as possible.