Table 1.
Physical and chemical properties of soil at different layers at Yucheng, Shandong Province of China in 1990.
Table 2.
Treatment and fertilizer nutrient rates (kg ha−1) applied to winter wheat and maize at Yucheng, Shandong Province of China.
Figure 1.
Grain yield of wheat (a) and maize (b) of different fertilizer treatments (Control, circle; NPK, triangle up; NP, triangle down; NK, square; PK, plus) under wheat-maize rotation system from 1994 to 2006 at Yucheng, Shandong Province of China.
Table 3.
Multi-year average grain yield of wheat and maize, as affected by various treatments with fertilizer in a wheat-maize rotation system at Yucheng, Shandong Province of China (mean±standard error).
Figure 2.
Yield gap variation of wheat (a) and maize (b) by N (GYGN, the yield difference between NPK and PK plots in each year, triangle up), P (GYGP, the difference between NPK and NK plots, triangle down), K (GYGK, the difference between NPK and NP plots, square) or NPK (GYGNPK, the difference between NPK and Control plots, circle) fertilizer omission from 1994 to 2006 at Yucheng, Shandong Province of China.
Table 4.
Multi-year average soil nutrient status at wheat and maize harvest, as affected by various treatments with fertilizer in a wheat-maize rotation system at Yucheng, Shandong Province of China (mean±standard error).
Figure 3.
Soil available N (a), Olsen-P (b) and available K (c) gap variation by N (SNGN, soil available nutrient difference between NPK and PK plots, triangle up), P (SNGP, the difference between NPK and NK plots, triangle down), K (SNGK, the difference between NPK and NP plots, square) or NPK (SNGNPK, the difference between NPK and Control plots, circle) fertilizer omission from 1994 to 2006 during wheat season at Yucheng, Shandong Province of China.
Figure 4.
Soil available N (a), Olsen-P (b) and available K (c) gap variation by N (SNGN, soil available nutrient difference between NPK and PK plots, triangle up), P (SNGP, the difference between NPK and NK plots, triangle down), K (SNGK, the difference between NPK and NP plots, square) or NPK (SNGNPK, the difference between NPK and Control plots, circle) fertilizer omission from 1994 to 2006 during maize season at Yucheng, Shandong Province of China.