Abstract: Yield response and farmland nutrient equilibrium were studied in fluvo-aquic soils of the North China Plain, and the results provided a theoretical basis for high yield-high efficiency and sustainable development of grain production on a field-block scale. Fertilization treatments were used in a long-term experiment to study yield response and farmland nutrient equilibrium. The 7-year fertilization experiment to study crop responses and farmland nutrient showed that for wheat the 7-year mean yields ratio of treatments CK, P₂K₂, N₂K₂, and N₂P₂ to N₂P₂K₂ were 25.5%, 34.5%, 43.3%, and 83.2% respectively while those for maize were 42.3%, 52.7%, 70.6%, and 76.2%. The N supply capacity of fluvo-aquic soils in the absence of N fertilizer declined to 59% of the original in the first year investigated, fell to 43% in the second year, and then fluctuated around 40% in the following years. Without P fertilizer application, soil P capacity decreased to 72% in the first year, fell to 55% in the third year, and then fluctuated around 55%. The K supply capacity without K fertilizer addition changed from 93% in the first year to about 76% in the 7th year of the experiment. The best treatments of farmland N equilibrium were N₂P₁K₂ and N₂P₂K₁, of P was N₂P₁K₂, of K was P₂K₂, and of N,P,K was N₂P₁K₂. The cumulative apparent recovery rates of N,P,K fertilizers on crops of wheat and maize were 44.3%, 31.2%, 53.0% and 40.8%, 28.9%, 50.3% respectively. There were significant correlations between amount of fertilizer and yield response. N was the main limiting factor for crop yield, then P and K. The better treatment for farmland N,P,K equilibrium was N₂P₁K₂.