Soil-testing and Formula Fertilization Index for Potato in Nan'an City

The 3414 multi-point tests of fertilization in potato field were conducted in Nan'an city,Fujian province during 2006~2008.The results showed that the application of N,P and K fertilizer was still an important way to increase the yield and income of the local potato production at present.The yield-increasing and income-increasing effects of different fertilization treatments had the following trend: NPKNKP,those per unit fertilizer revealed NPK,and the ratio of output to input showed NPK.Soil fertility had great influence on the fertilization effect in potato field.For the potato fields in Nan'an city,the low-grade standard of alkali-hydrolyzable nitrogen,available phosphorus and available potassium content in the soil was 100,19.6 and 36 mg/kg respectively;their middle-grade standard was 65～120,14.8～52.6 and 36～133 mg/kg respectively;their high-grade standard was 120,52.6 and 133 mg/kg separately.The recommended application rate of fertilizer for potato reduced along with the increase of the content of alkali-hydrolyzable nitrogen,available phosphorus and available potassium in the soil.The average application rate of nitrogen fertilizer for the highest potato yield in Nan'an city was(195.33±22.67)kg/hm2,and N∶P2O5∶K2O was 1∶0.36∶1.19.The average application rate of N,P2O5 and K2O fertilizer for the highest potato income was 192.60±20.26,66.06±13.23,210.13±57.28 kg/hm2 respectively.