Treatment | Cultivation duration (years) | Fertilization (kg ha−1 year−1) | Managements |
---|---|---|---|
CUL0 | 0 | No fertilization | Native grassland without grazing |
No irrigation and no tillage | |||
No herbicide and pesticide application | |||
70% of the aboveground biomass was mowed once a year for hay feed | |||
CUL5 | 5 | Compound fertilizer (350) and Urea (75) | Zea mays monoculture |
Irrigation with 1800 m3 ha−1 | |||
Conventional tillage within 25 cm and rotation with 15 cm | |||
Herbicide and pesticide application | |||
No maize stalk aboveground was left in the farmland | |||
CUL15 | 15 | The same as above | The same as above |
CUL25 | 25 | Urea (150) and diammonium phosphate (75) before 2005 | The same as above |
Compound fertilizer (350) and Urea (75) after 2005 | |||
CUL35 | 35 | No fertilizer application before 1990 | The same as above |
Urea (150) and diammonium phosphate (75) and 25 t ha−1 of manure between 1990 and 2005 and compound fertilizer (350) and urea (75) after 2005 | |||
CUL60 | 60 | The same as above | The same as above except no herbicide and pesticide application before 1990 |