Chicory is grown as a forage crop for livestock. Iowa produces the largest corn crop of any state. The corn crop in New England failed. Rice is also a wage commodity for workers in the cash crop or non-agricultural sectors. Farmers have found the use of chilies effective in crop defense against elephants. Slave labor demands varied based on region and on the type of harvest crop. Pompeii was fortunate to have had fertile soil for crop cultivation. Wheat is a staple crop from Canada. Their central estimates of changes in crop yields are shown above. Pathogens can lead to high reductions in crop yield. Reaping is the process of harvesting a crop. Wallace was particularly interested in corn, the key crop in Iowa. Pakistan's largest food crop is wheat. Pests are less predominant in polycultures than monocultures due to crop diversity. Polyculture theoretically maintains soil fertility and protects against losses due to crop failure.