Water use; Farmers vs. home gardeners
Can you find information that provides statistics about why farming/agriculture in New Mexico(preferred) uses more water than home gardening?
There are several reasons why farming/agriculture uses more water than home gardening, but first it is important to distinguish "use" and "consumption". Agricultural water use in all state's is significant, sometime representing as much as 90% of a state's water "use". However, depending on how efficiently the water is used the actual amount of water consumed (lost to the atmosphere) is typically considerably less. Plus, agricultural land use (acres of crops) is significantly more than the land acres of home gardens which is why farming uses more water than home gardens.
With that said, many home gardens are very efficient in their water use, especially in transportation and application efficiencies. And this brings up your second point...
For example farmers may irrigate using miles of open ditches which are open to sunshine and heat causing evaporation, while home gardeners can direct the water right to the plants.
Open ditches typically lose water through either evaporation or seepage. Evaporation is considered a high inefficiency factor because the water is "lost" to the atmosphere. On the other hand, water seeping from the canal/ditch can (and in most cases will) make it's way back to a river or stream. Many ditches/canals, and the people that use them, would prefer not to lose any water to seepage or evaporation, but unfortunately it is very expensive to line ditches with concrete (to prevent seepage) or install underground pipes (to prevent seepage and evaporation). Therefore, many ditches/canals are unlined. Most water rights account for this evaporation and seepage loss (also called the "duty of water").
When comparing these agricultural systems to home gardening systems it is clear that most home gardening systems can be much more efficient transporting the water to the landscaping (assuming home gardens use municipal water sources). The cost of underground municipal water pipes is staggeringly high, but that cost is lessened when spread over thousands, or hundreds of thousands, of rate payers. This makes it more feasible for home gardens to irrigate more efficiently than many large farms.
I'm sorry I can't provide any statistics as I am lacking a good understanding of the exact question. It's like comparing apples and oranges. If you would like more specific conversation or statistics please let me know.