March 16, 2012

See related story: Western Corn Belt May be Shy of Moisture until Late Summer with update on current wheat condition in Nebraska.

High Plains Region

The current U.S. Drought Monitor indicates moderate to severe drought conditions across portions of the eastern Dakotas, southern Minnesota, northwestern Iowa, and extreme northeastern Nebraska. Much of this dryness can be traced to a lack of low pressure systems impacting the region since last August. Much of the late summer and early fall period was dominated by high pressure aloft that kept precipitation well north and south of the region.

During the late fall, La Nina conditions reestablished in the Equatorial Pacific and led to the development of a split flow jet stream pattern across North America. Unfortunately this pattern resulted in little significant moisture as low pressure systems generally passed north and south of the upper Midwest. Precipitation departures since October 1 are running 3-4.5 inches behind normal. If normal moisture is received through the remainder of the growing season, I am projecting a 7.5-10% dryland corn yield reduction for northeastern Nebraska.

With the lack of snow cover, temperatures averaged over 8 F above across the northern High Plains. Bitter cold air invaded the Dakota’s on several occasions during January leaving winter wheat exposed without protective snow cover. Four inch soil bare soil temperatures reached single digits at every automated weather data site located in North Dakota for three consecutive days. Estimates are that over one million acres of winter wheat may have experienced significant winter kill injury.

With temperatures soaring into the 60s and 70s these past few weeks, winter wheat has broken dormancy as far north as South Dakota. Across southern Kansas wheat has reached the joint stage. With forecasts indicating that warm temperatures will continue for the next two weeks, jointing will likely progress northward toward Nebraska. If a hard freeze materializes after late March, it is likely that the potential production loss would be comparable to the 2007 April freeze event.

If the warmth and dry conditions continue into April, planters are likely to roll immediately after the April 10th crop insurance deadline for preventive plant protection. If corn emerges before April 20th, a freeze during the first half of May would have the potential to catch the corn crop in the 6-leaf or later stage. The growing point would be above the soil surface and total crop loss would be expected.

From a soil moisture standpoint, early corn planting hastens the demand for water by a developing crop. Planting two weeks earlier is the equivalent of taking 1.5 inches away from soil water storage if normal precipitation is received. Early corn planting does reduce the risk of heat stress during pollination, but it is a very risky proposition because you are adding another 2-5% yield reduction potential even with normal moisture during the growing season.

Most of the southern half of the High Plains region has received near normal to above normal moisture and stands an excellent chance of having adequate soil moisture reserves heading into the growing season. The only exception lies across the southern half of Missouri where isolated pockets of 3 plus inch departures since October 1 exist With normal spring and early growing season precipitation, odds currently favor above trend line corn yields during 2012. The most likely area for planting delays lies from south central Kansas northeastward through eastern Iowa.

Midwest Region

Only a couple of small pockets of excessive dryness can be found in the region. The most significant departures since October 1 lie in the northwestern corner of Wisconsin and a small area of northeastern Wisconsin and the southwestern corner of the upper peninsula of Michigan. Almost all of Indiana and Ohio have been excessively wet for much of the winter with a surplus of 3-9 inches recorded since October 1.

With most locations reporting at least 15 inches of moisture since last fall, soil profiles are at or above field capacity. If spring storm activity results in normal moisture, there is a high probability that some planting delays will materialize. The counter argument is that above normal temperatures will push producers into their fields earlier than normal giving them a longer period to sow their crops.

This area faces two production scenarios this growing season. With soil moisture profiles at field capacity, normal to above normal moisture during May and early June could promote the development of a shallow root zone making the crop exceptionally vulnerable to a short and intense dry spell during the growing season. If planting is able to proceed at a normal pace and drier than normal weather develops for several weeks after emergence, excellent rooting structure should be expected. Thus, crop stress wouldn’t be expected to develop (if at all) before mid-June.

Although some pockets of dryness are evident from northeastern Illinois southwestward into southern Missouri, normal moisture through the end of April would bring soil moisture profiles to near field capacity. Since rainfall has been much less significant compared to the eastern Corn Belt, good rooting structure for developing corn should be expected barring a shift to exceptionally wet conditions during the spring planting season. With normal growing season moisture, normal to above normal corn yields would be anticipated.

Southern Region

After a devastating drought year during 2011, an area encompassing eastern Texas and Oklahoma, Arkansas, Tennessee,, Louisiana, and northern Alabama have received 15-30 inches of moisture since last October. Wheat condition rankings entering into winter dormancy were at their highest levels in the last 20 years for Texas, Oklahoma, and southern Kansas. The abundance of moisture has been a pleasant surprise this winter considering that La Nina winters usually bring dry conditions to the region.

Western Texas, Oklahoma, and Kansas have seen better moisture this winter than during the same 2010-2011 period, but it has been insufficient to undo last season’s drought damage. High winds have been a persistent problem as upper air low pressure systems swing into the southern Plains promoting rapid surface drying and blowing dust. Top soil moisture may be sufficient to promote spring growth, but deep subsoil moisture is non-existent and timely rains will be needed to avoid a yield hit to production this growing season.

Forages were hit especially hard last year and forced producers to seek alternative pastures or truck in forage stocks from outside of the region. If dryness leads to drought conditions across the northern and central U.S., competition for northern Plains forage stocks could be intense. If a hard freeze hits the wheat crop in this region during the next month, this may become a moot point since producers would likely bale damaged wheat as a supplemental forage crop.

I can’t emphasize enough that the wheat crop in this region is well ahead of normal. A freeze from this point forward would likely result in greater damage than the April 2007 event. The crop is two weeks ahead of the 2007 pace and there is a high probability that above trend line wheat yields can be expected if a freeze fails to develop. This assumes that precipitation will be normal and disease/pest issues will not be a detrimental impact to production.
Further eastward, dryness has been an issue for areas east of the Appalachian Mountains from Georgia northward through the Carolinas. Precipitation has been running less than half of normal within the Atlantic coastal plain region. While temperatures have promoted rapid spring growth, timely rainfall will needed for producers to have a chance at decent crop yields.

Under normal circumstances, frontal boundaries will shift north of the region as the main storm track moves toward southern Canada. Air mass thunderstorms are typical during the summer, but coverage is localized. It isn’t until August or later that organized tropical systems can impact the region with heavy rainfall. Therefore, organized spring storms are important to build subsoil moisture reserves as a bridge until late summer tropical activity begins. If normal moisture is not received during the next 60 days, significant yield reductions similar to 2011 can be expected.

Al Dutcher
Extension State Climatologist