Late Season Timothy Fertilization

Turf grass managers consider a very late fall application of fertilizer to be the most important fertility application. How would cool season forage grasses respond?
Late Season Timothy Fertilization - Articles

Updated: August 8, 2017

Late Season Timothy Fertilization

Turf grass managers consider a very late fall application of fertilizer to be the most important fertility application. Managers consider late applications to be important for the initiation of tillers and to optimize winter survival of these tillers. On turf applications of approximately 40 pounds of N per acre are applied. This brought up the question of how cool season forage grasses would respond to a similar type fertility program.

A field trial in Adams County investigated the application of 200 pounds/acre of 10-20-20 fertilizer to an established timothy stand in November 2007 to measure crop yield effect. Fertilizer was applied to approximately 10 acres of timothy within a larger field (28 acres) of a two year old timothy stand on November 21, 2007. Fertilizer was provided by Agricultural Commodities Inc., New Oxford, PA. The entire field (28 acres) was treated for Cereal Rust mites, broadleaf weeds and top-dressed with nitrogen in April 2008. On June 17 the field was cut and on June 20, 2008 baled using a Heston, large, square baler.


In March 2008 a noticeable greening up difference was observed. Unfortunately tiller counts were not taken but the treated area appeared to have a denser stand and a more rapid green up prior to spring top-dressing than the untreated area.

Dry matter yields were taken by counting bales from the treated and untreated areas. A weight of 1200 pounds per bale was used to estimate yields. Dry matter yield results showed a 0.5 T/acre increase in yield of the treated verses the untreated area.

Total Area
Total Bales
Untreated17.7 acres
10.3 acres

Economical Consideration

To estimate economic return on this investment the cost of the fertilizer was compared to the return on forage dry matter yield. Value of the timothy hay was based on a range of values, from $150 to $200/ton. A 0.5T/ac increase in yield would be equal to a return of $75.00 if hay price was $150/ton; $87.50 @ $175/ton; and $100 @ $200.00/ton.

Cost of fertilizers has dramatically increased from November 2007 to July 2008. Two prices are compared, November 2007 - $400/ton and July 2008 - $895/ton. At a rate of 200#/acre of 10-20-20 a cost for fertilizer application would be: November 2007 price ($40.00/acre) and July 2008 ($89.50/acre). At the November 2007 cost of the fertilizer the yield gain exceeded cost for all values of the harvested crop. However, at the July 2008 cost the fertilizer expense exceeds all crop returns except at the $200/ton hay price.


Questions have been raised as a result of this investigation. Does the late addition of nutrients result in additional production of plant tillers in the fall and/or do these nutrients result in greater survival of existing tillers during the winter dormancy period? Are these results achieved with a complete fertilizer or would a straight fertilizer provide similar responses? What about timing? Can nutrients be applied too early? Is this only possible for timothy or would other cool season grasses respond similarly? Nevertheless, these results indicate that timothy stands may be a good location to apply late fall manures where good ground cover and yield response may prove beneficial and be safe for the environment compared to corn stubble fields.