The researchers studied how efficiently soybeans and wheat use phosphorus fertilizer in a semi-arid area. They tested different amounts of phosphorus on both crops and found that wheat needs more fertilizer to grow well, while soybeans can use the phosphorus already in the soil. Wheat also moves more fertilizer into its grains than soybeans. Both crops stop benefiting from extra fertilizer after a certain point. Soybeans need less phosphorus to reach their maximum yield compared to wheat.