role of pulses in lowerimg water carbon footprint
Answers
Food production, along with transportation and energy production have large impacts on greenhouse gas concentrations in our atmosphere. Agriculture alone accounts for 10-12% of global greenhouse gas emissions1.
As explained in "Pulses use half the non-renewable energy inputs of other crops", pulses require little to no nitrogen fertilizer, due to their ability to biologically fix nitrogen from the air. The manufacturing of essential nitrogen fertilizer is energy intensive, and natural gas is used to drive this process2. Knowing this, it is obvious why growing nitrogen-fixing pulses would result in less greenhouse gas emissions to the atmosphere. But this is only half the story.
When soil is fertilized with nitrogen in the form of fertilizer, manure or crop residues, soil microorganisms convert some of this nitrogen to nitrous oxide, a gas which can escape to the atmosphere3. Nitrous oxide is a powerful greenhouse gas; with 298 times the global warming potential of carbon dioxide4. Nitrous oxide represents 60% of the greenhouse gas emissions from Canadian agriculture and the application of nitrogen fertilizer represents the largest source of nitrous oxide from Canadian agricultural soils (35% of direct emissions)5.
Since crop production greenhouse gas emissions are largely driven by nitrogen fertilizers, farmers that grow nitrogen fixing pulse crops are doing their part to reduce global greenhouse gas emissions!6,7,8,9 But consumers have to do their part as well. Next time you are at the grocery store, look for pulses, and products with pulse ingredients.
When soil is fertilized with nitrogen in the form of manure, fertilizer, or crop residue, soil micro-organisms convert some of this nitrogen into nitrous oxide, which is a powerful greenhouse gas. Nitrous oxide is 300 times more potent than carbon dioxide (CO2) and represents around 46% of the greenhouse gas emissions from global agriculture1.
Since greenhouse gas emissions related to crop production are largely driven by nitrogen fertilizers, nitrogen-fixing pulse crops have a lower carbon footprint compared to other crops.
When pulses are grown, they use 1/2 to 1/10 the water of other sources of protein 2. Many pulse crops are adapted to dry environments, making them well-suited for areas that are prone to drought.
Pulses like peas and lentils extract water from a shallower depth, leaving more water deep in the soil for the following year’s crop. This increases the water use efficiency of the entire crop rotation.