Joel Bagg, Forage Development Specialist & District Sales Manager, Quality Seeds Ltd
Dry weather has significantly reduced forage regrowth and second-cut yields in most parts of the province. Many dairy farmers are off schedule for their normal 4-cut system. There is some growing concern over having adequate forage inventories to meet livestock needs, with consideration of alternate forage options following winter wheat and other cereals. Many drought-stressed fields are also showing symptoms of boron and sulphur deficiencies, and some potato leafhopper damage. Be careful not to overgraze drought-stressed pastures because it will significantly reduce total seasonal pasture yields. Although it may seem counter-intuitive, supplementing hay now rather than overgrazing pastures actually saves hay in the long run.
To Cut Or Not Too Cut?
A question often asked during extended periods of severe dry weather with poor growth is “should I cut or not?” Cutting decisions should be made on a case-by-case basis, depending on the condition of the stand and whether rain is in the forecast. Moisture stress during the 2 weeks following cutting results in a reduced number of stems per crown and reduced regrowth. Significant alfalfa growth will not occur until some drought-ending rains occur. Short, drought-stressed alfalfa yields are significantly reduced, but forage quality is usually higher than normal, even when plants are flowering. The stem internode length is reduced and the leaf-to-stem ratio is high. Harvesting at later maturity will allow alfalfa plants to build root reserves for better regrowth when rain returns. As a general suggestion, stands greater than 10 inches tall and in full flower should be harvested. In stands less than 10 inches tall, delaying cutting is suggested because yield are low and mowing will not increase growth until significant rainfall occurs. To enable faster grass regrowth, grassier stands should not be cut less than 4 inches high. Drought-stressed new alfalfa seedings should not be harvested unless mowing is needed to control weeds.
Alternate Forage Options
Many farmers are examining options to increase their forage inventories. An early winter wheat harvest enables more time for better volunteer wheat control and timely planting of alternate forage crops. Seeding oats or oat-pea mixtures in late-July or early-August following wheat for an early-October harvest as haylage or baleage can be a useful low-cost option for extending forage supplies. The challenges can sometimes be lack of adequate moisture in August for germination and growth, and having dry enough weather in October for adequate wilting.
(Summer Seeding Oats For Forage http://fieldcropnews.com/2013/07/summer-seeding-oats-for-forage/ )
QS “Evolution” Italian ryegrass can produce very high quality, leafy, palatable forage suitable for high producing dairy cows. It can be seeded in August following wheat for harvest in late-fall and then again the following May, making it an excellent double-crop option if managed properly. Evolution is noted for its high fibre digestibility (NDFD), high relative forage quality (RFQ), palatability, ease of establishment, and its yield response to nitrogen. (“Evolution” Italian Ryegrass Forage Options http://www.qualityseeds.ca/blog/3-evolution-italian-ryegrass-forage-options )
Boron Deficiency In Alfalfa
Boron deficiency symptons can be seen in many alfalfa stands. It is characterized by a yellowing or reddening of the upper leaves of the plant, and is sometimes referred to as “yellow top”. Lower leaves will stay green. The field, or patches in the field, assume a bronze color. Stem growth between leaves becomes shortened, giving plants a stunted appearance. It is sometime confused with potato leafhopper damage, but with boron deficiency the discolouration appears on leaves at the top of the plant, while with potato leafhopper the discoloration appears on both the upper and lower leaves.
Boron deficiency shows up mainly on high-pH, sandy soils and is seen most frequently on droughty soils under dry conditions. In Ontario, it is more common east of the Niagara escarpment.
Growth can be severely stunted and winter hardiness reduced. Confirming a boron deficiency can be done by tissue testing with a properly taken sample and laboratory analysis. Boron deficiency can usually be corrected or prevented by a broadcast application of 1.0-2.0 lbs/acre of boron blended with the P and K. (http://www.omafra.gov.on.ca/english/crops/pub811/3fertility.htm#micronutrients )
Figure 1 - Boron deficiency appears on the upper leaves of alfalfa, becoming yellow to red and stunting growth. (Photo credit – OMAFRA)
Potato Leafhopper Damage
Potato leafhoppers (PLH) are being reported at damaging levels in alfalfa in some parts of the province, including areas where they are not typically an issue. Damage is often confused with moisture and heat stress, and dismissed as “drought damage”. Control of PLH can significantly reduce drought stress and provide additional yield. New seedings are very susceptible and can be permanently damaged, so be sure to check these fields. Once the wedge-shaped yellow “hopperburn” is observed, the damage is done and it is too late for control. (Potato Leafhopper In Alfalfa http://www.qualityseeds.ca/blog/19-quality-time-with-joel)
Figures 2 & 3 – Potato leafhopper “hopperburn” symptoms start as a “V” yellowish pattern on the leaf tips. Injury is most severe in new seedings and in young regrowth. (Photo credit – OMAFRA)