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Fall is a good time to control quickgrass

Detroit Lakes,Minnesota 56501
Detroit Lakes Online
Fall is a good time to control quickgrass
Detroit Lakes Minnesota 511 Washington Avenue 56501

Fall is an excellent time to control quackgrass with glyphosate type products. Harvested silage corn, edible beans, soybean, small grain fields or pre-plow old hayfields, are ideal sites for fall quackgrass control. Ideal timing is from late August to early October. The question often asked is: "How late can I treat quackgrass with Roundup?"

Rather than worry about the calendar, it is best to determine if the field meets the following criteria: 1) Quackgrass at least 6 inches tall, green, actively growing, and not covered with crop residue. 2) No visible signs of frost injury on quackgrass leaves (quackgrass can tolerate light frost without damage, so the occurrence of a frost does not preclude the use of Roundup later in the fall). 3) Minimum daytime high of 50 degrees Fahrenheit (60 degrees preferred). 4) No risk of rain for at least two hours. Suggest six hours if temperatures are cool. 5) Wind less than 10 mph.

If all five criteria are met, fall glyphosate application should be very effective on quackgrass. Remember that the likelihood of meeting all five criteria diminishes as we get later into the fall. For best results, apply at a rate of at least 1qt/A. Always add ammonium sulfate (AMS) at 17 lbs/100 gal to the spray solution. Tank mixing may reduce glyphosate activity on quackgrass (antagonism) and should be avoided if the target weed is quackgrass.. Adding AMS is critical if tank mixing with other herbicides.

Remember that the fall is also a good time to control broadleaf weeds, such as thistles, knapweed and dandelions in lawns, pastures and roadsides. Scouting and controlling weeds in the fall can have great weed reduction results. For more information please contact: Will Yliniemi, Hubbard/Becker County Extension Educator at 1-218-732-3391, 1-218-846-7328 or by cell at 1-218-252-1042, or by email at:

Phosphorus facts and water quality

Phosphorus (P) is a somewhat unique pollutant in that it is an essential element, has low solubility, and is not toxic itself, but may have detrimental effects on water quality at quite low concentrations. There is considerable concern about P being lost from soils and transported to nearby streams and lakes. Several chemical properties of soil P have important implications for the potential loss of P to surface water.

n Phosphorus in soils is almost entirely associated with soil particles. When soil particles are carried to a river or lake, P will be contained in this sediment. When the sediment reaches a body of water it may act as a sink or a source of P in solution. In either case, it is a potential source of P that may eventually be released.

n Most soils have a large capacity to retain P. Even large additions of P will be mostly retained by soils provided there is adequate contact with the soil. Increasing the amounts of phosphate in soils results in increased levels of phosphate in soil solutions. This will generally result in small but potentially important increases in the amounts of phosphate in water that passes over or through soils.

n Phosphate in soils is associated more with fine particles than coarse particles. When soil erosion occurs, more fine particles are removed than coarse particles, causing sediment leaving a soil through erosion to be enriched in P.

What are the implications for this area of the state? It is important to note that the coarse textured sandy soils in the lake region of this area of the state are generally outwash sands, which are naturally high in phosphorus. (This may represent a natural level 2-5 times higher than the glacial till soils). This is why it is critical that erosion and sediment transport of those soils to surface water be minimized. If fertilizer is to be applied to lake landscapes, use fertilizer that is phosphate free (Remember that the middle number in a fertilizer analysis is the P percentage: 23-0-15). Also, note that organic fertilizers (Manure, Compost, etc.) can serve as a potential source of phosphorus contamination.

Maintaining and enhancing vegetation and ground cover, using phosphorus free fertilizer (organic or inorganic), slowing down and diverting runoff water, protecting water resources from erosion/sedimentation during construction, reducing hard surface areas, and thinking water quality in all your landscape and farming activities will make a difference in reducing the potential of phosphorus contamination of surface water. For more information please contact: Will Yliniemi, Hubbard/Becker County Extension Educator at 1-218-732-3391, 1-218-846-7328 or by cell at 1-218-252-1042, or by email at: