thirtieth of the daily usage in some developed nations. Collier's work has focused on improving irrigation for notoriously thirsty cash crops, like cotton and sugarcane, although they are seldom grown on the smallest farms. Agriculture based on fields that temporarily flood is also a major problem because most of that water is wasted through evaporation. Added to these woes are pesticide and herbicide runoff from farm fields that pollute rivers and lakes, as well as soil erosion and salt buildup from irrigation.
