Healthy cattle pastures can limit harmful greenhouse gas emissions

A growing collection of studies has documented methane emissions from cattle and other grazing animals, but these animals actually emit other greenhouse gases as well.

Researchers at the International Center for Tropical Agriculture (CIAT) investigated nitrous oxide (N2O) emissions, which are released from cattle urine, and found that these emissions can be significantly limited by keeping cattle pastures healthy.

The team collected urine from cattle at research sites in five countries across Latin America and the Caribbean. They distributed the urine samples on pairs of cattle fields that were classified as degraded or healthy based on vegetation coverage. The study revealed that degraded pastures emitted up to three times as much nitrous oxide, which has an even greater influence on global warming than carbon dioxide.

“Degraded pastures are bad in so many ways,” said study lead author Ngonidzashe Chirinda. “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 findings highlight the urgency of global land restoration agreements like Initiative 20×20, which aims to restore 20 million hectares of land in Latin America by 2020, among other targets.

Degraded livestock land is characterized by overgrazing, soil compaction, loss of organic material, and low levels of nutrients and soil carbon. Chirinda estimates that there are 150 million hectares of degraded land in Latin America, with 80 million hectares of degraded pasture in Brazil alone.

Large-scale projects that restore grazing land with improved forage grasses and add new shrubs and trees could significantly mitigate the negative climate effects produced by degradation. In addition to reducing N2O emissions, restored landscapes can store more carbon, have healthier soils, and promote the growth of more productive livestock.

“This study highlights the importance of avoiding land degradation in the first place,” said study co-author Todd Rosenstock. “Maintaining healthy pastures appears to reinforce goals of both the United Nations’ Framework Convention on Climate Change and the UN Convention to Combat Desertification simultaneously.”

The study is published in the journal Scientific Reports.

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By Chrissy Sexton, Earth.com Staff Writer

Paid for by Earth.com

Image Credit: Neil Palmer/CIAT