Livestock farms need to match their animals with enough land to handle their manure in order to prevent pollution. A study in China found a way to measure how much manure different types of livestock produce and how much land is needed to handle it. They found that poultry, swine, beef, sheep, and dairy cows produce manure with different levels of nutrients. The study also showed that vegetable fields can handle more livestock than cropland or orchards. Livestock carrying capacity based on nitrogen was higher than that based on phosphorus, with a ratio of 6.6. By using manure and fertilizer more efficiently and changing the types of crops grown, livestock carrying capacity can be adjusted.