Integrated Pest & Crop Management Newsletter University of Missouri-Columbia Vol. 15, No. 20 November 18, 2005 Air on the Cool Side: A BTU Captured is a BTU Earned By Bill Casady The long warm fall seems to be finally coming to an end and not a day too soon for long term storage. It has been difficult to cool grain below 55 or 60 degrees until recently. Take advantage of naturally cool air now to increase storage life of grain. The cooling process is vital to slowing insect activity and keeps storage molds down as well. With recently higher costs for energy, it is also important to take the time to understand the energy resources used in the grain conditioning process. The differences in drying methods can be surprising. It is usually estimated that it takes about 1200 BTU’s to remove a pound of water from moist grain. This value is known as the heat of vaporization. If you were to measure the amount of heat that is actually exchanged in the process of removing moisture from grain, you would consistently measure about 1200 BTU’s depending on just how wet the grain is to begin with and some other factors. From experience, we know that to quickly dry grain can become rather expensive. We must buy more than 1200 BTU’s in order to remove each pound of water. There is obviously another factor that is just as important as the amount of heat energy that is required to remove a pound of water, and that is the energy efficiency with which the drying is accomplished. Drying efficiency explains what would be apparent exceptions to the 1200 BTU rule. A hurried drying process that uses high temperatures and lots of air can require up to 2400 BTU’s or more to remove the equivalent of 1200 BTU’s of water. A slower more natural drying method without additional heat might get the job done with the purchase of less than 800 BTU’s of electrical energy per pound of water removed to run aeration fans. This is about a three to one ratio, but the difference can be as high as four to one at extreme ends of the scale. We’re often taught that if something looks too good to be true, then it probably is too good to be true. In a comparative way to the use of heat pumps, there are often naturally occurring energy surpluses and deficits in ambient or natural air that we can take advantage of for the conditioning of grain for long term storage. We could say that there are two ways to capture the economy of ordinary or natural air in the grain conditioning process: drying with naturally warm and dry air in early fall, and cooling with naturally cool air in late fall. The use of fans to dry a grain mass with naturally warm fall air effectively concentrates air movement around kernels and increases the speed of the natural drying processes that would occur if grain was allowed to sit out in a thin layer under the sun... or for that matter, if the grain remained in the field on the stalk. The latter two obviously require essentially no energy purchase at all. The use of fans to cool a grain mass with naturally cool late fall air also concentrates air movement around kernels to cool the grain mass. Although it isn’t widely recognized in the north, chillers are sometimes used to improve the quality of some grains, such as rice, during the drying process and for long term storage. Naturally cool fall air avoids the need to pay for refrigeration of air. Natural air is "energy efficient" plain and simple. It is no more efficient to wait and do all of the cooling all at once. In fact it is a bit risky. Grain should have already been cooled with a couple of aeration cycles to about 50 or 55 degrees by now. If that is the case, one more good aeration cycle will nail down additional storage safety. Always take advantage of the naturally protective cooling nature has to offer as soon as possible to maximize the protective benefit of cooling. The best part is that aeration is almost free. Bill Casady 573 882-4370 ********* Impact of Herbage Allowance on Lactating Beef Cows Grazing Stockpiled Tall Fescue By L.E. Meinhardt and R.L. Kallenbach Efficient forage utilization by beef cattle is essential for optimum economic production and performance in a cow-calf operation. The most efficient way to utilize forage is by grazing; however, forage growth is dormant between late autumn and early spring. During this period, producers commonly rely on stored feed even though it is expensive. Use of stored feed accounts for 70 percent of the annual beef cow maintenance cost. Research at the University of Missouri found extending the grazing season into winter reduces dependence on stored feed and decreases winter-feeding costs by one-third to one-half (Bishop-Hurley and Kallenbach, 2001). One way to extend the grazing season is to utilize stockpiled tall fescue (Festuca arundiacea Schreb). Tall fescue, the predominant forage in the transition zone, lends itself well to stockpiling. It produces more autumn growth, maintains yield and quality throughout the winter, and responds to nitrogen fertilization better than other coolseason grasses. A great deal of research has been conducted on stockpiled tall fescue, although much of this research has been done on yield, quality, fertilization, defoliation, and accumulation (Berry and Hoveland, 1969; Collins and Balasko, 1981a, b; Fribourg and Bell, 1984; Kallenbach et at., 2003). There have also been several successful stockpile-grazing studies with gestating, spring calving beef cows and stocker calves (Allen et al., 1992a, b; Hitz and Russell, 1998; Tucker et al., 1989; Waller et al., 1988). In recent years, producers are switching to fall calving operations, and as a result more cows are lactating over winter. Only a few studies have documented using stockpiled tall fescue with lactating fall calving cows. Animals in these studies were typically allocated feed equal to three percent of their body weight each day with 70 percent utilization. Remarkably, the scientific basis for this allowance is largely unknown, yet the literature indicates that it is widely accepted. As fall calving gains popularity, the importance for an appropriate herbage allocation level increases. Lactating cows have much higher nutrient requirements than gestating cows (NRC, 2000) and may require higher herbage allowances. On the other hand, it may be economical for cows to loose body condition in the winter, when forage supplies are limited, and regain weight when lush spring growth occurs. However, research is needed to evaluate the most economical herbage allowance of stockpiled tall fescue for lactating fall calving beef cows. It is less expensive to maintain a lactating cow on lower herbage allocation levels than higher allocations; however, this does not mean that the lower allocations are the most economical. Forcing high utilization rates with low allocation levels may limit cow intake causing excessive weight loss, decrease reproductive performance, and decreased milk production resulting in reduced calf gain. Spring regrowth may also be adversely affected by low allocation levels. Some studies show that spring growth is not affected by grazing stockpiled during the winter (Allen et al. 1992a; Riesterer et al., 2000) while other studies report decreases in spring yield (Hall et al., 1998). Research is limited on why these contradictions occur. Animal performance when consuming tall fescue herbage is often hindered due to a fungal endophyte, Neotyphodium coenophialum [(Morgan-Jones and Gams) Glenn, Bacon and Hanlin]. The endophyte infection results in an accumulation of toxic alkaloids know to cause a series of animal health disorders, costing the United States livestock industry an estimated $609 million annually (Hoveland, 1993). Resent research indicates endophyte toxicity should be less severe in stockpiled tall fescue. However, there is insufficient evidence on the effects of grazing infected stockpiled tall fescue on cow-calf performance. The objectives of this trial are: 1) establish optimum daily herbage allowance for lactating beef cows and their calves wintered on stockpiled tall fescue, 2) estimate dry matter utilization rate of stockpiled tall fescue at different herbage allocation levels, 3) observe the impact of grazing endophyte infected tall fescue over-winter on animal performance, and 4) determine the effect of herbage allocation level on spring regrowth. Conventional winter hay-feeding practices will also be evaluated for an economical comparison with stockpiling tall fescue. Answering these objectives is necessary to maintain a profitable fall calving herd throughout winter. Materials and methods The experiment was conducted in a randomized complete block design with three replications and four stockpiled tall fescue at herbage allowances treatments; 2.25, 3.00, 3.75, and 4.50 percent of cow and calf body weight per head per day (BW hd-1 d-1). Sixty, cow-calf pairs were stratified into twelve groups and then assigned to treatments at random. The first year of the experiment began on 2 December 2004 and ended 24 February 2005. Stockpiled tall fescue was strip-grazed with forage allocated every 3.5 days. Pre-grazing herbage mass was determined at the beginning of the experiment and every 21 days thereafter, by clipping ten, 32 inches x 15 feet strips from each pasture. Strips were cut to as near as ground level as possible. Cows and calves were weighed and body condition scored at the beginning of the experiment and every 21 days thereafter. All cows were maintained on hay from 24 February until weaning on 20 April 2005. The experiment will be repeated again this winter. Year one project summary The first year of allocation data collection has been completed. Cows allocated herbage at 2.25 percent of BW hd-1 d-1 lost the most weight (avg. daily loss of 2.3 lb hd-1 d-1), while the other three allocation levels did not differ (avg. daily loss of 1.9 lb ha-1 d-1). Calves in the 2.25% BW hd-1 d-1 treatment had an ADG of 1.2 lb hd-1 d-1 while those in the 4.5% BW hd-1 d-1 had an ADG of 1.6 lb hd-1 d-1 (Table 1). Since the acres required to winter a cow-calf pair would double between the lowest and highest allocations, economic analyses suggest stockpiled tall fescue should be allocated levels at 3.0 percent BW hd-1 d-1. In addition, cow and calf performance data taken later in the spring at weaning time showed no significant differences between stockpile allocation treatments imposed during the winter. Rob Kallenbach Ag Ext-Plant Sciences 573-882-2801 ******** Warm Soil Temperatures put Fall Anhydrous Ammonia Applications at Risk By John Lory Soil temperatures north of I-70 have remained well above normal in the first half of November. The average daily six-inch soil temperature under soybean stubble has been in the mid to upper 50s for much of the period. These temperatures are warm enough to allow significant conversion of anhydrous ammonia to nitrate. Farmers who have already applied anhydrous ammonia need to be aware that a wet winter and spring could lead to substantial losses of fall-applied nitrogen. Fall nitrogen applications are not recommended until soil temperatures stay well below 50 degrees. Typically this occurs in mid- to late November. This year soil temperatures were still too warm to recommend fall applications of anhydrous ammonia in northern Missouri as of November 15. To track soil temperatures in your region visit the on-line University of Missouri weather resources at http://agebb.missouri.edu/weather/stations/index.htm. John Lory Environmental Nutrient Management 573-884-7815 ******** 2005 Crop Management Conference The 2005 Crop Management Conference will be held December 14-15, 2005 at the Holiday Inn Select Executive Center in Columbia, MO. For more information visit http://muconf.missouri.edu/cropmgt/index.html. Below is a list of conference sessions. Insect Pest Management Management profiles for important and emerging corn, soybean, wheat, and alfalfa insect pests will be identified and explained Soybean Rust Factors that affected soybean rust incidence in southern US states and Missouri will be identified. The outlook for soybean rust in Missouri in 2006 will be discussed. Weed, Insect, and Disease Updates for 2006 Discussion of label changes, new pesticide chemistry, and emerging pest management strategies Identification of Herbicide Injury Symptoms on Crop Plants Update on identifying herbicide injury to important Missouri crops Biofuels The ethanol and biodiesel industries in Missouri will be discussed with emphasis on how Missouri farmers can participate Sunflowers Discussion of management and marketing of sunflowers in Missouri Energy Efficient Crop Production: Managing Energy Uncertainty The session will address the impact of high fuel prices and strategies to reduce energy needs for crop production. Soybean Cropping Systems Relay cropping of soybean into wheat and the use of earlymaturing soybean varieties in Missouri will be discussed Winter Utilization of Kentucky 31 Tall Fescue Discussion of management strategies to reduce the harmful effects of ergovaline in hay and the use of fescue stockpiling for lactating beef cattle. Nitrogen Management in Uncertain Times Supply and price outlook for nitrogen products and discussion of the impact of changing supply and prices on nitrogen management decisions in grains and forages. Corn Color and Nitrogen Management Discussion of the remote sensing of corn color and how it can be used to derive nitrogen fertilizer rates Roles of Certified Crop Advisers and Private Industry in Technical Service Provider Programs The technical service provider program will be described including recent changes and updates. The processes by which CCAs can become involved will be discussed NRCS Programs Can Provide Financial Incentives for Cropping System Improvements EQIP, CSP and other NRCS programs related to environmental stewardship will be discussed Weather Information Management Software and other Farm Information Systems An on-site computer lab will include instruction on the use of software and web-based information systems to help assess and use weather and other information to improve crop and livestock production on your farm while decreasing the impact of agriculture on the environment. ******** Weather Data for the Week Ending November 18, 2005 By Pat Guinan -------------------------------------------------------------------------------- | Monthly | Growing Weekly Temperature (deg. F) |Precip (in.)|Degree Days^ -----------------------------|------------|------------ Ext- Ext- Depart| Depart| Deprt Avg.Avg. reme reme from |Nov 1- from |Apr 1 from Station County Max.Min. High Low Mean avg. |Nov 15 avg. |Oct 31 avg ------------------------------------------------------|------------|------------ Corning Atchison 59 36 78 24 48 +7 | 0.55 -0.68| 4040 +738 St. Joseph Buchanan 58 39 76 29 48 +6 | 0.40 -0.61| 3855 +453 Brunswick Chariton 59 34 71 26 48 +5 | 0.94 -0.59| 3945 +469 Albany Gentry 58 31 73 22 46 +5 | 0.55 -0.64| 3697 +301 Auxvasse Audrain 59 38 69 30 49 +5 | 0.68 -1.10| 3969 +478 Columbia Boone 59 39 71 31 49 +4 | 0.67 -0.79| 4021 +371 Sanborn Field Boone 60 41 72 34 51 +6 | 0.77 -0.70| 4244 +514 Novelty Knox 58 35 69 28 47 +4 | 0.89 -0.82| 3726 +308 Linneus Linn 58 34 69 24 47 +5 | 0.62 -0.77| 3744 +423 Monroe City Monroe 59 36 70 28 48 +5 | 0.80 -0.91| 3859 +366 Versailles Morgan 61 40 73 31 51 +5 | 0.86 -0.71| 4282 +556 Green Ridge Pettis 59 39 71 30 50 +6 | 0.75 -0.95| 4105 +670 Lamar Barton 64 40 72 28 52 +5 | 0.95 -0.86| 4273 +332 Cook Station Crawford 65 36 71 28 51 +4 | 2.56 +0.56| 3763 -40 Delta Cape | | Girardeau 68 40 78 31 54 +7 | 3.42 +1.57| 4147 -20 Cardwell Dunklin 70 45 80 35 58 +9 | 1.89 +0.22| 4654 +131 Clarkton Dunklin 70 43 80 36 57 +8 | 2.12 +0.22| 4585 +122 Glennonville Dunklin 69 43 80 34 57 +8 | 1.27 -0.64| 4517 +79 Charleston Mississippi 68 42 78 35 57 +9 | 2.29 +0.69| 4432 +332 Portageville- | | Delta Center Pemiscot 70 46 79 38 60 +11 | 0.73 -1.14| 4728 +301 Portageville- | | Lee Farm Pemiscot 70 45 79 36 59 +10 | 1.00 -0.82| 4703 +306 Steele Pemiscot 71 45 80 39 59 +9 | 2.22 +0.53| 4806 +370 -------------------------------------------------------------------------------- ^Growing degree days are calculated by subtracting a 50 degree (Fahrenheit) base temperature from the average daily temperature. Thus, if the average temperature for the day is 75 degrees, then 25 growing degree days will have been accumulated. -------------------------------------------------------------------------------- Pat Guinan, Commercial Agriculture Program (573) 882-5908