Pilot study on Guangdong techno-index system of soil testing and fertilization in leafy vegetables: phosphorus

Where the vegetable fields were according to different fertility levels of different locations in Guangdong province,the leaf vegetable fertilization tests were set in the fields presented by Pakchoi(Brassica Chinesis) and Flowering Chinese cabbage(Brassica parachinensis Bailey).In this paper,the test data of phosphorus application amount,the soil available nutrient of phosphorus,the relative yield of vegetables and relative phosphorus uptake rate were analyzed statistically,and the regression equation was also acquired.Base this,the index of soil available phosphorous on Olsen-P and the application phosphorus rate were obtained.(1)Index sufficiency and deficiency of soil available phosphorus were based by used of one model which relative yield was y=12.36ln(x)+38.495(the correlation coefficients was 0.685),and the other model which relative phosphorus uptake rate was y= 18.513ln(x)+11.517(the correlation coefficients was 0.685).The index of application phosphorus rate of the Flowering Chinese cabbage were based by used of one model which was y=-1.274ln(x)+8.3839(the correlation coefficients was 0.649).The index of application phosphorus rate of the Pakchoi were based by used of one model which was y=-0.3871ln(x) +3.3416(the correlation coefficients was 0.637).(2)According to the model were obtained the sufficiency and deficiency range which the soil effective phosphorus were respectively5 mg/kg,5～25 mg/kg,25～95mg/kg,95 mg/kg,which the relative product were respectively 50%,50%～ 75%,75% ～95% and 95%.(3) The proposed application phosphorus rate of Flowering Chinese cabbage and Pakchoi were respectively 6.3 mg/kg and 2.6 kg per 667 m2,when the soil available phosphorus was 5mg/kg.Meanwhile,the proposed application phosphorus rate of Flowering Chinese cabbage and Pakchoi were 4.3～6.3 kg and 2.0～2.6 kg per 667 m2,when the soil effective phosphorus was 5～25 mg/kg.And the former were 2.6～4.3 kg and 1.5～20 kg per 667 m2,at the range of 25～95 mg/kg of the latter.When the soil effective phosphorus was orer95 mg/kg,the total application phosphorus should be less than 2.6 kg per 667 m2 of Flowering Chinese cabbage and 1.5 kg per 667 m2 of Pakchoi.