No abstract

A decline in pasture productivity is often associated with a reduction in vegetative cover. We hypothesize that nitrogen (N) in urine deposited by grazing cattle on degraded pastures, with low vegetative cover, is highly susceptible to losses. Here, we quantified the magnitude of urine-based nitrous oxide (N2O) lost from soil under paired degraded (low vegetative cover) and non-degraded (adequate vegetative cover) pastures across five countries of the Latin America and the Caribbean (LAC) region and estimated urine-N emission factors. Soil N2O emissions from simulated cattle urine patches were quantified with closed static chambers and gas chromatography. At the regional level, rainy season cumulative N2O emissions (3.31 versus 1.91 kg N2O-N ha−1) and emission factors (0.42 versus 0.18%) were higher for low vegetative cover compared to adequate vegetative cover pastures. Findings indicate that under rainy season conditions, adequate vegetative cover through proper pasture management could help reduce urine-induced N2O emissions from grazed pastures.

The burgeoning demand for rice in Latin America and Caribbean (LAC) exceeds supply, resulting in a rice deficit. To overcome this challenge, rice production should be increased, albeit sustainably. However, since rice production is associated with increases in the atmospheric concentration of two greenhouse gases (GHGs), namely methane (CH 4) and nitrous oxide (N 2 O), the challenge is on ensuring that production increases are not associated with an increase in GHG emissions and thus do not cause an increase in GHG emission intensities. Based on current understanding of drivers of CH 4 and N 2 O production, we provide here insights on the potential climate change mitigation benefits of management and technological options (i.e., seeding, tillage, irrigation, residue management) pursued in the LAC region. Studies conducted in the LAC region show intermittent irrigation or alternate wetting and drying of rice fields to reduce CH 4 emissions by

Cassava (Manihot esculenta Crantz) is the world's second most important starch source, after maize, and a staple food for up to 800 million people in tropical countries (Howeler et al., 2013). The ability of cassava to be productive under poor soil conditions has resulted in the mistaken assumption that it does not require soil amendments, the avoidance of which has led to low cassava yields and constrained its profitability (Kintché et al., 2017). Nonetheless, several studies have reported a yield response with fertilization (Howeler, 1996;Pellet & El-Sharkawy, 1993). Fertilization of cassava is also necessary to maintain long-term soil productivity (Howeler, 2011). Cassava has been grown in soils that received complementary and sole fertilization of organic and inorganic soil amendments (Ayoola & Makinde, 2007;Susan John et al., 1998). In rural communities, the application of inorganic fertilizer is common among resource-rich