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Bowls In Focus : August September 2011
42 Bowls In Focus The current public concerns over the effects of global warming and the problem with carbon pollution has prompted me as a layman to try and clarify the role of carbon as it affects us as turf growers and users. I have not gone into the technical chemical processes involved with plant growth and soil carbon retention as it leaves me more confused than normal! Carbon dioxide is essential for all plant growth, Through the process known as photosynthesis, leaves of plants, including trees, convert carbon dioxide into organic carbon compounds known as carbohydrates. Planting trees on agricultural land to store carbon only happens while these trees are alive. Soil carbon is known as the end result of the plant carbon cycle. Carbon that is fixed by plants is moved into the soil by dead plant material such as leaves and dead roots, where bacteria and fungi get to work on this organic matter and convert it into soil carbon. Soil carbon improves the physical properties of soil giving a better water holding capacity and reduces nutrient leaching which means better plant growth. Carbon is a natural component of soils. Heavier soils such as those in forested areas have a much higher carbon level than the free draining sandier type soils. Generally speaking, since agriculture was introduced into Australia these carbon levels have decreased and are lower than similar areas in Europe, while New Zealand natural soil carbon levels are much higher than our natural levels because of our large variation in climatic conditions ranging from tropical vegetation to large expanses of country with low rainfall and sparse plant cover. I am not aware of any research relating to soil carbon retention in turf areas, but within Australia for a number of years there has been agricultural research, especially in relation to crops and pastures. The change for cropping has been significant where two processes are involved: reducing emissions by increasing the efficiency of farm operations and limiting the former cultivation practices. Pasture research, which is closely related to our major sporting areas has been on improving plant species or varieties to give better yields and maintaining permanent pastures to increase organic soil levels. Bowling greens are constructed from sandy type soils and these are the ones that naturally have low soil carbon levels. It is usual when constructing greens or with major renovations to include an organic compound which is mixed into the base soil. This is to assist with nutrient retention and to improve the water holding capacity. As the turf ages the organic level rises and so does the soil carbon level. A number of golf clubs, racecourses and sports ovals including some bowling clubs are using carbon-based fertilisers to keep couch grasses green during the normal dormant period. Some of these compounds include nitrogen, phosphorous and potassium; hopefully these nutrients will be retained in the soil long enough to encourage spring growth. I would be inclined to use a carbon compound on couch grass when it is actively growing. Bent grass greens could be treated any time during the year. A research project is needed to come up with firm recommendations. On the downside current research with pasture grasses and some crops has shown that at higher soil carbon levels nitrogen reserves are being locked up and growth is restricted. The other problem is that carbon is continually breaking down and being released back into the atmosphere as carbon dioxide, so the cycle, especially with bowling greens, possibly needs to be maintained with carbon additives. There was a letter published in a weekly rural paper questioning the number of volcanic eruptions in the last few years quoting carbon dioxide figures that negated every effort by the human race to control carbon dioxide emissions. I presume that volcanoes do release carbon dioxide, but they have been erupting for centuries or even longer and that would have been taken into consideration in the current calculations. I think this last comment will be of interest in the continuing carbon dioxide debate. Greens Management Max Fielder Greens Concealed Carbon Bowling greens are constructed from sandy type soils and these are the ones that naturally have low soil carbon levels.
June July 2011