Table 1. Background data of productivity and soil fertility of the experimental fields studied from 2011 to 2012.

Year	pH	Water content(%)	Organic matter (g/kg)	Total N(mg/kg)	Available P(mg/kg)	Available K(mg/kg)
2011	6.50	20.32	15.64	1.57	53.26	112.48
2012	6.76	18.94	14.83	1.62	51.82	110.34

Data were collected from 0 to 20 cm soil samples in early spring before irrigation each year.