I work at an immigration law firm. Probably 70 percent of my cases are people from India, 20 percent from China, and the rest from everywhere else. Those "brown" Indians are waiting 14 years, or more for their green cards. I have people who came to the US when they started college, got a Master's degree, got a job in 2001, and their employer immediately started the green card process, and they still don't have a green card. For a legal immigrant to get a green card, their employer has to show that there are no qualified US workers.
There is a visa category for farmworkers, and the Dept. of Labor allows the public to see what applications have been filed. There are hardly any that have been filed in the past few months, which tells me that there are a lot of people who aren't even trying to follow the law in hiring foreign workers, and that bothers me.