by Micah Woods, Ph.D.
[email protected]
www.asianturfgrass.com

Everyone knows that the weather has a huge influence on the growth of turfgrasses, and the weather is one thing that a golf course superintendent cannot control. I have had the opportunity to visit many cities around the world where warm-season grasses are grown, and I am struck by the differences in turfgrass species that thrive in one place and that struggle in another. For example, I have seen kikuyugrass grow well at Lanai and San Diego and at Dalat in the mountains of southern Vietnam, and I know kikuyugrass grows well at many locations in South Africa, but when it is grown at Bangkok kikuyugrass cannot compete with other grasses that grow more aggressively in the Bangkok weather.

The same differences in turf vigor are seen with other warm-season species such as bermudagrass, seashore paspalum, and zoysiagrass. I made this bubble chart to show the average weather data (climatological normals) for different cities around the world, thinking that by looking at the weather data in this way we might be able to get a better understanding of why certain grasses perform better in one area but do not thrive in another.

These data are from the climatological normal tables on the Hong Kong Observatory website and the bubble charts were created using the ggplot2 package in R. If you are interested in seeing these plots on a monthly basis, please go to www.blog.asianturfgrass.com where I have already uploaded the files for May and June average weather and I will be uploading a new bubble chart around the first of each month until April of next year, showing how the average weather for different world cities changes throughout the year on a monthly basis.

Click Here to download the Climatological Normals bubble chart to see How Honolulu compares with the rest of the world

The Environmental Protection Agency’s Tier 4 diesel engine emission reduction mandate will soon have an impact on your business. Tier 4 compliant Turf Equipment, in the 25 to 74 horsepower (hp) category, manufactured after January 2013 will be better for the environment and healthier for everyone, but it will also cost more.

Understanding the financial implications of various compliance options – today – will allow you to evaluate all of your options, in advance, so you can make the most beneficial decision for your business.

The EPA Tier 4 Standard is about cleaner air!

All US regulated emission standards, including Tier 4 for off-road diesel engines, are extensions of the “Clean Air Act” (1963) which was enacted to reduce air pollution in the United States. The “tiered” mandates were put in place to progressively reduce the level of harmful emissions such as Particulate Matter (PM) and Nitrogen Oxides (NOx) that enter the air via diesel engine exhaust. The most stringent emission reduction mandate to date, is called “Tier 4”. The Tier 4 emission standard will reduce emissions of PM by 90% from current levels.

CLICK HERE to download the complete “Tier 4” brochure

from TurfNet Monthly November 2004
by Micah Woods

Turfgrass professors tell us that more roots are obtained at higher potassium levels, but plant science researchers tell a different story…

Earlier this year I presented  some preliminary results from  the soil testing studies I have been  conducting at Cornell University to a meeting of the Central NY GCSA. Many in the audience were interested  to know how potassium fertilizer applications, or the withholding of potassium fertilizer from the turf, had affected the L-93 creeping bentgrass roots in the study. I did not have any final data to share at that time, but the audience’s pointed questions about rooting certainly underscored in my mind the widespread, traditional assumption that potassium plays a critical role in turfgrass rooting.

In Turfgrass  Science and Culture (Beard, 1973), it is clearly stated that higher soil potassium levels yield increased root development and branching. The recently published Turfgrass Soil Fertility and Chemical Problems (Carrow et al., 2001) emphasizes the role of potassium in sand rootzones, where potassium encourages “a more extensive fibrous or branched root system.”  The theory of root stimulation by potassium is propagated and promulgated anew whenever superintendents or turfgrass students are taught about turfgrass nutrition. I recently participated in an online seminar about fall fertility strategies for cool-season grasses, and sure enough, we were reminded by the instructor that a primary plant response to potassium is deeper roots with more branching.

Turfgrass professors tell us that  more roots are obtained at higher potassium levels, but plant science researchers tell a different story. The definitive plant nutrition reference is Mineral Nutrition of Higher Plants (Marschner, 1995), in which Marschner wrote that mineral nutrient supply can strongly influence root growth, with nitrogen having a particularly marked effect, less so for phosphorus,  and usually no effect for other nutrients.

A classic study of the effect of variable ammonium, nitrate, phosphate, and potassium supply on barley roots [Drew, 1975] found that the number and length of lateral roots were stimulated by all nutrients except for potassium. In fact, some plants have more roots when no potassium is applied [Cherney et al., 2004], perhaps because the roots explore a larger volume of soil in order to obtain the potassium that they need.

So why, I wondered, are we taught that potassium increases roots, even though the consensus among plant scientists is that potassium has little effect on roots?

CLICK HERE to download the complete article