The actual state of phosphate and potassium application and soil chemical properties in orchards in Fukuoka prefecture, [Japan]
2009
Fujitomi, S.(Fukuoka-ken. Agricultural Research Center, Chikushino (Japan)) | Kuroyanagi, N.
By using results of the soil surveys conducted from 1997 to 2007 on orchards in Fukuoka Prefecture, we examined the relationship between the amount of fertilizer applied during the period and the nutrient accumulation in the soil with respect to phosphate (P2O5) and potassium (K2O). The amount of efficient nutrient in animal manures and composts (organic material: OM) was estimated by multiplying the total nutrient contents by the efficiency factors of the nutrients. We estimated the total amounts of fertilizer application (ETFA) by adding the value thus obtained to the chemical fertilizer actually applied. The findings are summarized as follows: 1) The ETFAs in phosphate and potassium were 1.3 times and 1.2 times higher than the average values in the standard application rates of fertilizer. 2) The average value of available phosphate content in soil was 154 mg/ Truog-P2O5 100 g, which was significantly higher than the targeted value in soil improvement objective (from 20 to 50 mg/Truog-P2O5 100g). 3) In the OM application points, the phosphate ETFA was conspicuously large. It was indicative of the tendency that large quantities of available phosphate accumulate in soil corresponding to OM application. 4) The available phosphate amounts tended to decrease, roughly corresponding to the reduced phosphate ETFA. 5)The exchangeable potassium amounts tended to be in excess in about 20% of all the points tested, while the average value was 46.2 mg/K2O 100g, which is lower than the average value for Japanese orchards as a whole. 6) The potassium ETFA in the OM application points was larger than that in the OM non-application points, but the exchangeable potassium amounts were not different between these points.
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