ISSUE 15   September 17, 2009

SUBSURFACE DRAINAGE

Although surface drainage is a component of a successful water management system, subsurface or tile drainage is also a very important management practice in agricultural production systems. Tile drainage can help to establish more optimum conditions for field operations and crop growth by lowering the water table in poorly drained soils.

Limited studies by Cannel on wheat response to drainage have been conducted and show significant responses of wheat to water table depth.

Iron deficiency chlorosis (IDC) is a major issue in the soybean production areas of eastern North Dakota and northwest Minnesota. Moisture is one of the factors influencing the severity of IDC. In fields were salts are a contributing factor to IDC, tile drainage will reduce the salt concentration in the root zone over time.

Phytophthora root rot caused by Phytophthora sojae might be a serious problem when the soil is excessively wet (Dr. Berlin Nelson, NDSU Soybean Plant Pathologist, personal communication and Nelson et al. 1996). Tolerance to water-saturated soil and role of resistance to Phytophthora sojae was reported by Helms et al. (2007).

Saturated soil conditions can stress plants and may limit plant growth and yield. Limited oxygen in soils has a negative effect on plant growth. Fehr and Caviness reported a 20% soybean yield loss after three days of saturated soil conditions at the V2 and V3 stages. Recent studies by Dr. Ted Helms indicated an interaction between soybean genotypes grown under saturated and natural rainfall conditions. The average yield of 40 soybean varieties under saturated conditions was 26.3 bushel compared with the natural rainfall yield of 33.2 bushel per acre. This is a 20% yield reduction for the beans grown in saturated conditions.


Photo: Installation of tile at the NDSU
agronomic research field at NW22, Fargo, ND.

Although tile drainage is a very popular water management practice in the corn belt and in southern Minnesota, there has been limited tile installation in North Dakota and northwest Minnesota, until very recently. Information in this region (ND and NW MN), from farmers who have tile drainage, suggests that there are some real benefits to be gained from subsurface drainage. Farmers maintain that tiled fields are now those where field operations take place first, instead of last. Producers with tile drainage list a number of benefits they receive from tile drainage including: higher yield, lower fuel cost to work the tiled ground, less wear and tear on equipment, better timeliness of all field operations, better and more uniform crop stands, better weed control, fewer field ruts, less soil compaction, and better overall soil tilth.

Earlier planting, particularly for cool season crops such as field pea, canola, and spring wheat, often results in higher yields because the crop avoids high temperatures during the critical grain fill phase in its development.

However, flat topography, tight soils, economic uncertainty, and a tradition of surface drainage only, limit widespread adoption of tile drainage in the region. Both technical and economic feasibility must be clearly understood before tile drainage becomes a widely accepted water management practice in the eastern part of North Dakota and northwest Minnesota.

References:

Helms, T.C., B. J. Werk, B. D. Nelson, and E. Deckard. 2007. Soybean Tolerance to Water-Saturated Soil and Role of Resistance to Phytophthora sojae,
Crop Sci., 47(6): 2295 - 2302.

Nelson, B.D., J.M. Hansen, and C.E. Windels,1996. Races of Phytophthora sojae on soybean in the Red River Valley of Minnesota and North Dakota,  Plant Disease. Vol. 80, no. 1, 104 p.

Hans Kandel
Extension Agronomist broadleaf crops
hans.kandel@ndsu.edu

 

PROSPECTS FOR LATE MATURING CORN

As we all know too well, 2009 has been a cool summer and the crops in North Dakota show it. The small grains responded favorably to the weather and have produced record yields in most of the state. Corn on the other hand still has a long way to go, and is way behind schedule, even with the above average temperatures we were blessed with this past week. Based on the USDA-NASS report for the week ending September 13th, the corn crop in ND was only 23% dented compared to 70% for the average of 2004-2008. Perhaps of an even greater concern, however, is that the corn crop is substantially behind last year when 52% of the corn crop was dented. Most everyone can remember vividly the state of the corn crop at harvest last year!

The intent of this article is to provide some background about corn development and field dry-down so that we might have a better perspective of how the corn crop might finish this year. Of course any prediction is dependant upon weather and predicting weather is not my strength. Nevertheless, past weather data can provide us a glimpse of what may be in store this fall.

Where are we at now with corn development?

We are currently running about 200-250 growing degree days (GDDs) behind normal and about 75-150 GDDs behind last year. At this time of the year that probably translates into about 10-15 calendar days behind normal. As of September 13th, assuming a 1 May planting date, we had accumulated 1977 GDDs in Fargo and only 1699 in Carrington. Based on the approximate GDD requirement from planting to black layer (see Table 1), in Fargo we need an additional 288 and 323 GDDs for 86 and 93 RM hybrids, respectively. Assuming an October 1st killing frost, it looks unlikely that a full season hybrid will be able to reach physiological maturity (or black layer) this year. The scenario is much more disconcerting when we calculate the GDDs needs in Carrington. Table 2 summarizes the approximate number of calendar days required for corn in different stages to reach maturity. Though these data were developed using long season hybrids (i.e.105 RM) in the Corn Belt, they probably still apply to our hybrids in ND as our weather is substantially cooler in the fall than Iowa and Illinois, slowing down the process. Our own research last year found that it took 66 days for an 85 day hybrid to reach maturity from silking. It might be interesting for you to add 66 days to your silking date this year to see how close this year will be to last year for reaching maturity (30% moisture).

Table 1. Approximate GDD requirements of corn hybrids of differing maturities to reach key growth stages.

RM of Hybrid

GDD to pollination

GDD to black layer

GDD pollination to black layer

79

1095

2040

945

86

1175

2265

1090

91

1200

2300

1100

95

1245

2410

1165

Table 2. Approximate number of calendar days for corn in different stages to reach maturity (Adapted from the National Corn Handbook, 1986).

Stage

Calendar days to maturity

Silk

55-65

Blister

52

Late milk/ Early dough

39

Early dent

25

Fully dented

12

What kind of losses might we anticipate this year?

First of all, the cool summer weather does not necessarily mean that we will have poor yields. In fact, we had record corn yields last year, even though the season was unusually cool. Generally the corn crop looks good this year, so there is reason to believe that we could have another high yield crop. The unknown is how soon the season will end. Table 3 describes the type of yield loss that can be expected from a killing frost occurring at various stages before maturity. Obviously, the closer we get to maturity the less the loss and the greater the test weight. Late dent seems to be a threshold where the losses will not be excessive and where test weight approach the level that the grain will not be discounted.

Table 3. Effect of time of killing frost on yield and test weight of corn (adapted from Hicks, 2004).

Stage

Yield Loss(%)

Test Weight (lb/bu)

Soft Dough

55

35-40

Early Dent

32

47

Dent

27

50

Late Dent

15

53

Half Milk Line

8

55

What about in field dry down?

Reaching maturity is only half of the story. The other half is that the grain must dry sufficiently to allow for harvest and to minimize drying costs. The rate of field dry down is largely regulated by temperature, the moisture content of the kernel (dryer kernels have a slower rate of dry down than wet ones) and to a lesser extent relative humidity. Typically, because of cool temperatures, the rate of drying is exceeding slow after the third week of October. So in reality, our hope is that the grain will reach black layer (~30%) and dry to 20% or less before the first of November. We have been measuring the rate of dry down for the past two years (see Figure 1 for data from Carrington). Last year we found a loss of about 0.25% moisture per day for the period September 29th to November 20th. The decline in moisture loss is notable after the end of October because cool weather and a few rainfall events.


Figure 1.

The relationship between GDDs and dry down is more predictive than the relationship between calendar days and dry down. Last year, we found that 1% moisture loss required 11 GDDs (Figure 2). We also found that GDD accumulations more or less ceased by the end of October last year, reinforcing the notion that most of in field drying is finished in the fall by the beginning of November.


Figure 2.

What about letting corn dry over the winter?

As many farmers learned this past year, leaving corn over the winter in the field can be a viable option. Even with all of the snow we received, most reports indicated that corn dried down to very manageable levels and that field losses were tolerable. I think that field losses were tempered last year because we went into the winter with very good stalk strength. We had minimal stress to deplete stalk reserves prior to the killing frost. We will probably have good stalk strength again this fall since we have not seen significant stress in most fields; rains have been timely and temperatures moderate. We collected data on field dry down during the winter last year in one field in Cass County (Figure 3). As you can note, most of the serious drying occurred after the third week of February when temperatures started to warm, and were at about 16% moisture by mid-March.


Figure 3.

Conclusion

As you can note in the above paragraphs, I am reluctant to predict how the corn crop will end this year. Obviously the crop is late and the likelihood of a frost before maturity is quite high. I think we have a reasonable chance of escaping huge yield losses, however, if we are able to move into October without a killing frost. The crop may even dry enough for some serious harvesting in early November if October and November weather is not abnormally cold.

Joel Ransom
Extension Agronomist for Cereal Crops
joel.ransom@ndsu.edu

 

WHY PROTEIN CONTENT MATTERS IN HARD RED SPRING?

After a late spring and relatively cool summer, the spring wheat harvest is finally more than 50% complete. Initial reports of production yields and test weights are coming in positive; however, protein content is lower across the region compared to last year and the five year average. Reports of protein discounts for HRS wheat below 14% of $0.50 to $1.00 per percentage point are being reported. Protein premiums above 14% are also being reported.

Protein is not an official grading factor, but it is an important marketing factor for establishing economic value. Hard Red Spring (HRS) wheat is priced in the market based on 14% protein on a 12% moisture basis. This is due to the fact that most of our domestic and international markets purchase 14% protein HRS for the production of high protein flour for bread products that require high levels of gluten. HRS is also blended with lower protein wheat to boost the baking quality for bread production.

The protein content of the wheat is directly related to the bread making properties of the milled flour. Baking absorption (amount of water added to make an optimum dough), dough strength, and loaf volume generally increase as protein content of the wheat is increases. The increased consumption of whole wheat and whole grain breads in the U.S. has strengthened demand for high protein HRS wheat, as the higher protein helps overcome the weight of the bran and germ generally extracted in the milling of white (refined) flour. Breads that contain other grains and oilseeds also benefit from the extra protein in whole wheat flour made from HRS wheat, as consumers expect these products to have similar texture and loaf volume as conventional white pan breads.

The substantial protein discounts below 14% are also a result of a lower than average protein content in the U.S. Hard Red Winter wheat crop harvested earlier this summer. Millers and bakers around the world are concerned about the availability of high protein milling wheat, resulting in the discounts being observed at this time. As the market price for high protein HRS increases, additives to make up for low protein flour become an option economically for bakers. The primary additive is vital wheat gluten (VWG), which is extracted from wheat flour in the production of wheat starch most of which is produced outside of the U.S. It is termed "vital" since the protein is carefully processed to retain its vitality or functionality when added in the making of bread. Wheat gluten became a household word two years ago with the pet food safety crisis caused when wheat gluten adulterated with melamine was imported from China, causing illness and death in many dogs and cats in the U.S.

Gluten is a term that refers to the protein complex that forms during the dough mixing process. Gluten proteins provide the cohesive, visco-elastic and gas retention properties of bread dough that result in the open crumb structure of wheat breads. Gluten quantity and quality vary with the six U.S. wheat classes and determine the functionality or end-use quality. Low protein or low gluten wheats (i.e., Soft White or Soft Red Winter) are preferred for cakes, cookies, and pastries. High protein or high gluten wheats (Hard Red Spring and Hard Red Winter) are used for breads, rolls, tortillas, noodles, pasta and other wheat based foods.

Brian Sorenson
Director of the Northern Crops Institute


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