Effect Of Potassium Fertilizer Levels On Growth Physiology And Nutrient Utilization Of Pepper

In order to solve the problems of scarce potassium resource,inadequate potassium fertilizer supply,excessive potassium fertilizer application and low utilization in China,�Longjiao No.5� was used as material by pot experiment and substrate culture were applied to study physiological growth,photosynthetic characteristics,nutrient uptake and allocation,nutrient utilization,yield and quality of pepper fruits under different potassium level in this research.Five treatments were set as follows: no-fertilizer treatment?CK?,fertilizer treatment?T1,T2,T3,T4?.The potassium?K?fertilizer application rates in T1,T2,T3 and T4 were set according to the 30%,40%,50% and 60% of potassium utilization efficiency in turns.This research was aimed to provide theoretical foundations for precision application of K fertilizer in pepper production.The main results are as follows:1.Under the same level of nitrogen?N?and phosphate?P?fertilizer application rates among different treatments?N 33.42 kg/667m²?P₂O₅ 16.03 kg/667 m²?,K application rate with suitable amount?K₂O 43.4 kg/667 m² in T2?can significantly promoted plant height,stem diameter,root activity,accumulation of dry matter and accumulation rate in pepper plants.Compared with T1?K₂O 57.9 kg/667 m²?,T3?K₂O 34.7 kg/667 m²?and T4?K₂O 28.9 kg/667 m²?,the dry matter accumulation of pepper fruit in T2 was improved 5.1 %,8.2% and 17.1% respectively.2.In T2 treatment,photosynthetic pigment content,Pn,Tr and Ci,Fv/Fm,?PSII and q P in pepper leaves were significantly increased,while Gs and NPQ were decreased,of which Pn under T2 conditions was13.8%,14.5%,30.9% higher than T1,T3 and T4 respectively.3.The total K uptake was significantly raised with the increasing K application rate,the total K uptake in T1 was 4.9%,30.6%,49.2 % higher than T2,T3 and T4 respectively.The total N uptake and P uptake were increasing with the rising K application rate within a certain range,while the total N and P uptakes will decreased due to the excessive K application rate.Under T2 condition,the total N uptake of pepper plants was 3.7%,7.3%,11.3% higher than T1,T3 and T4,the total P uptake was 8.1%,14.2%,20.6% higher than T1,T3 and T4 respectively.T2 treatment improved the N and P uptake rate and nutrient allocation in pepper fruits remark ably.4.In T2 treatment,the apparent recovery efficiency?ARE?of N,P,K in pepper plants were maximal,of which the ARE of N has increased 1.3,2.54 and 4.19 percentage points,the ARE of P has increased 2.92,4.76 and 6.61 percentage points,the ARE of K has increased 7.97,1.4 and 1.74 percentagepointsthan T1,T3,T4,respectively.Under T2 condition,3.63 kg N,1.47 kg P and 4.80 kg K were absorbed in the production of 1000 kg pepper fruits.5.In T2 treatment,per fruit weight and yield were significantly higher than other treatments,of which pepper yield was 3.3%,6.2% and 10.4% higher than T1,T3 and T4 respectively.Meanwhile,Vc content was increased significantly while nitrate content was decreased in T2.