Carrington Research Extension Center
North Dakota State University
NDSU Extension Service
North Dakota Agricultural Experiment Station

Ag Alert


10 June 1999

LIMITS ON LATE WILD OAT HERBICIDE APPLICATION IN WHEAT

Delays in controlling wild oat in wheat have occurred due to adverse weather conditions. The following are the wheat and wild oat stage limits for POST herbicides:

  Wheat Wild oat
Assert up to jointing 4-leaf
Avenge prior to flag leaf emergence 5-leaf
Achieve up to boot 6-leaf
Puma 6-leaf (prior to jointing) 2-tiller
Tiller up to 6-leaf (HRS only) 2-tiller
Cheyenne end of tillering or 6-leaf (HRS only) 4-leaf
Hoelon up to 4-leaf 4-leaf

Refer to herbicide labels and NDSU Extension Service circular W-253 '1999 North Dakota Weed Control Guide' for required information on use.

CONSIDER WARM-SEASON FORAGE CROP FERTILITY

The fertility needs of warm-season forage crops including hay millet, sudangrass, sorghum-sudan, etc. are often neglected. The crops are usually grown on poorer soils. Also, this year's abundant moisture may have leached available nitrogen below the relatively shallow root system of these crops. Use a soil test to determine nutrient needs. If soil test information is not available, suggestions for fertilizer application are 15 to 60 pounds of nitrogen (N) per acre on recropped ground and 15 to 25 pounds of phosphorus per acre. An example of forage yield and quality response to fertilizer was indicated in a foxtail millet N fertility trial conducted in 1992 at the Carrington Research Extension Center. Millet forage yield was 3200 pounds per acre and 5.9 percent crude protein with the unfertilized treatment compared to a yield of 4260 pounds per acre and 9.0 percent crude protein with an application of 50 pounds per acre of N.

LEAF RUST PRESENT IN WHEAT

Recent field surveys have indicated leaf rust present in winter and spring wheat. Low levels of rust has been found in counties including Foster, Griggs, Sargent, and Stutsman. Producers are encouraged to monitor fields for leaf rust, especially if susceptible varieties are grown. In 1998, susceptible spring wheat varieties identified included ACBarrie, 2375, Ingot, ACMajestic, and Lars.

What impact does leaf rust have on yield? Based on Kansas State University data, wheat in the flowering stage with 10% severity on the flag leaf is predicted to cause 10% yield loss, 40% severity may cause 20% yield loss, and 100% severity may cause 35% yield loss. As wheat reaches later growth stages the impact of leaf rust on yield is reduced. For example, at the soft dough stage, 10% rust severity on the flag leaf is predicted to cause 1% yield loss, 40% severity may cause 4% yield loss, and 100% severity may cause 10% yield loss.

If use of fungicides appear economical, refer to NDSU Extension Service circular PP-622 '1999 Field Crop Fungicide Guide' and fungicide labels for product selection and use.

HAY PRESERVATIVES DO WORK

Even though experienced haymakers will comment that hay preservatives provide nothing more than what 2-4 hours of sunshine can do, it's getting the sunshine that's unpredictable. Also, baling hay at higher moisture reduces leaf and dry matter losses in the field and during baling. The reduction in losses could offset the cost of applying hay preservatives.

Alfalfa and other hays store best when moisture is below 20%. However, rain and soil moisture can delay hay drying and consequent baling. Hay preservatives can be used to bale hay at higher moistures (up to 30% or higher). However, preservatives have a cost in both application machinery (up to $3000 for automated equipment) and preservative product (up to $16 per ton for 30% moisture hay).

Hay preservatives have been classed into 9 types: organic acids, acid salts, salt (NaCl), anhydrous ammonia, urea, fermentation products, anaerobic bacterial inoculants and aerobic bacterial inoculants. The organic acids (propionic, acetic, citric) are very effective in preventing mold and heating. As hay moisture content increases, the amount of acid needed increases.

 

Application rate for propionic acid

hay moisture % of dry weight lbs of acid per ton
20 - 24% 0.5 10
25 - 29% 1.0 20
29 - 30% 1.5 30

To reduce corrosiveness, propionic acid can be buffered with ammonium hydroxide. Some manufactures are mixing buffered propionic acid with citric acid (used to retain green color) and using lower application rates for reducing mold and heating. Product cost is suggested at $4 per ton of hay baled at 18-22% moisture, $8 for 22-26% moisture hay and $16 for 26-30% moisture hay.

Acid salts (i.e. sodium diacetate), applied as liquid or granule, are very effective and cost competitive. However, white salt (NaCl) needs to be applied in high amounts to be a preservative. Lower application rates of salt may only increase palatability.

Anhydrous ammonia is an effective fungicide but preserving effects will be temporary unless hay is covered plastic. Urea appears to be an effective preservative when applied at 4% but intake should be monitored for toxicity concerns.

Microbials can be effective in preserving hay. However, microbials developed for aiding ensiling appear to have variable effectiveness when used for hay preservation. Microbials seem to work best with liquid application and maybe priced less than the organic acids.

Storage of microbial solutions needs to be followed strictly to manufactures' recommendations to retain bacterial viability. As with organic acids, microbial products will help prevent dry matter and crude protein losses during harvest and will also prevent losses of crude protein, NDF and ADF during storage.

Producer interest in hay preservation peaks during rainy weather. However, field and storage losses can be high when hay is baled too dry (up to 35% dry matter loss for legumes). Baling at higher moisture content by using preservatives during non-rainy weather patterns should be considered.

For more information, contact Karl Hoppe, Area Extension Livestock Specialist, or try the following web sites: www.ext.nodak.edu/extnews/procrop/hay/preser06.htm
www.uwex.edu/ces/forage/pubs/preserv
www.pioneer.com/xweb/usa/nutrition/hayaddit2.htm
muextension.missouri.edu/xplor/agguides/crops/g04575.htm
www.colostate.edu/Depts/CoopExt/PUBS/CROPS/00705.html

(K. Hoppe)


Greg Endres, Area Extension Specialist/Cropping Systems, Email: gendres@ndsuext.nodak.edu
1999 Ag Alert Archive * Carrington R&E Center Home Page * NDSU Agriculture