This has been the hot issue of debate for a year or more. It is already a known fact that the ‘holy cow’, or ‘goddess’ as we worship it, contributes considerable amount of Methane to atmosphere, which is produced at the time of digestion, is expelled continuously to the atmosphere.
Now, interestingly, a recently published science report says that cows can also boost the production of this climate gas in SOIL as well. A team of German scientists from the Institute of Soil Ecology of the GSF – National Research Center for Environment and Health and Czech colleagues at the Budweis Academy of Science, have been able to show that these bovine animals can also boost the production of this climate gas in SOIL.
Researchers say, this happens in the soil in the pastures, where these animals graze intensively. During this point of time, the soil becomes more compact and the microscopic plants of the soil get compressed. In addition, this area gets very high amount of organic matter from the excrement of the animals, thus stimulating the production of methane.
Thus the study, carried out on a Czech farm, proved that two factors are vital for this process to take place: The amount and quality of organic material from the excrement and secondly, the strong compaction of the soil due to the weight of the cattle.
Grass lands that are not used intensively for agriculture generally act as sink for the greenhouse gases, methane, carbon dioxide and laughing gas (NO2). However, this situation can change if intensive management of the pastures with cattle occurs.
Indeed, it is known also that well-aired soils have the potential for producing methane. Hence, the scope of the study should also include examination of the extent to which the ‘over-wintering’ of cattle on pastures stimulates the production of methane, and grassland soils really become a methane spring.
The investigation was carried out on a farm in south Bohemia. In the process approximately four hectares has been used since 1995 for the over-wintering of about 90 cows from October till the beginning of May.
According to Researchers, “At the end of this season, we could clearly see the consequences of the over-wintering, on the soil.” Unlike typical summer grazing, where the animals spread out evenly, the animals on the winter pastures prefer to stay near the feed house. As a result, no vegetation was visible more in the wide area. But at the places where animals grazed intensively, it was found that the ground was strongly compressed. In addition, this area was marked by a very high incidence of organic matter from the excrement of the animals.
The intensive grazing in the areas close to the cowshed led to a clear increase of methane emissions throughout the whole winter. These showed 1,000 times more production of methane than in the area where no bovine animals were kept.
But the classical process of methane oxidation, which is related to aerobic conditions, was restrained in the intensely grazed areas. According to Schloter, however, this is explained by the high quantities of urea in the ground.
The scientists were able to show further that methane producing micro-organisms from the gastro-intestinal tract of the cattle could survive in the soil and suppress parts of the microscopic plants in the compressed soil. The micro-organisms profited from the new environmental conditions in these soil, namely the extensive organic material.
Although in summer and autumn the animals were kept on other pastures, the composition of the micro flora barely changed in the strongly over-grazed areas. Indeed, the methane production rates clearly decreased during these months, because the continuous supply of organic material was absent, researchers said.
“We shall continue the project, because we also suspect consequences for the nitrogen cycle,” adds Schloter, a key researcher in the team. “In addition, we have possibly proved a very rare process in the strongly compounded areas, namely the anaerobic oxidation of methane.
All in all, it can be said that just about every agricultural measure has its positive and negative consequences. What weighs more in each case, however, is a social, rather than a scientific question.”
Edited by B Jayakishore
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