Greener Pastures Lessen Cows’ Impact on Climate

(CN) – Flatulence has long been identified as the main culprit in cattle’s detrimental impact on the climate, but a new study released on Tuesday indicates bovine urine may actually be worse for the planet.

white cows

The International Center for Tropical Agriculture conducted a study across Latin America and the Caribbean that found cattle urine releases nitrous oxide, a more pernicious greenhouse gas than methane. When let loose on ground with little vegetation coverage, cattle urine emits far more of the noxious gas than in greener pastures, the researchers found.

“Degraded pastures are bad in so many ways,” said Ngonidzashe Chirinda, a CIAT researcher and the study’s lead author. “This study adds to the case for land restoration. Degraded pastures not only affect food security and the livelihood of farmers today, but affects the livelihood of future farmers because they emit more gases that cause global warming.”

The study was published in Scientific Reports, an open journal managed by the publishers of Nature.

According to the study authors, their findings underscore the urgency for pasture restoration efforts already underway in many of the areas included in the study. One such effort, called Initiative 20×20 aims to fully restore 20 million hectares of land by 2020.

For the purposes of the study, the researchers rated land on a scale from degraded to healthy and looked at factors such as overgrazing, soil compaction, nutrient content, presence of organic material and soil carbon.

They found that land they characterized as degraded released significantly more nitrous oxide, often three times as much as healthier pastures.

“This study highlights the importance of avoiding land degradation in the first place,” said Todd Rosenstock, a co-author based at World Agroforestry (ICRAF). “Maintaining healthy pastures appears to reinforce goals of both the United Nations’ Framework Convention on Climate Change and the U.N. Convention to Combat Desertification simultaneously.”

The researchers recommend large-scale land restoration efforts including the introduction of improved forage grasses, rotational grazing and the planting of shrubs, trees and other foliage strategically aimed at mitigating the effects of livestock operations on the climate.

Brazil was particularly hard hit by land degradation as farming operations continue to encroach on the Amazon rainforest. The country is home to some 80 million hectares of degraded pastureland according to the study.

A notable outlier is Colombia, where researchers found the lowest level of nitrous oxide emissions of any test site in the study regardless of the extent to which the land was degraded.

Further investigation yielded a hypothesis that the forage grass used by Colombian farmers is a strong nitrogen inhibitor, preventing the wholesale release of nitrous oxide.

The researchers said that it not only offered insight into a little-known greenhouse gas contributor but also demonstrated the power of transnational collaboration in the scientific field.

The idea for the study was born at the center for tropical agriculture at in Cali, Colombia, where a team of doctoral students from across Latin America and the Caribbean – including Argentina, Brazil, Trinidad and Tobago and Nicaragua – devised the methodology and took it home to their respective countries.

“The power is in the number of data points from all the different countries,” said Chirinda.

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