Periods

Cropping system

Food crops/Cash crops

Fertilization Intensity

Fertilization Structure

Organic/Inorganic fertilizer ratio

N/P/K

1949-1978

2 to 3

9:1

98-above 700 kg N ha⁻¹ a⁻¹

9:1

From 1:0:0 to 1:0.29:0.09

1979-1989

3 to 2

8:2

738 - 437 kg N ha⁻¹ a⁻¹

3:7

1:0.23:0.005

1990-now

2

from 7:3 to 6:4

578 - 445 kg N ha⁻¹ a⁻¹

1:9 to 0:1

1:0.08:0.13