Effects Of Bag Controlled-Release Fertilizer On Nitrogen Polar Partitioning And Organ Development Of Peach Tree

As a new fertilization method,bag controlled-release fertilization technology was preliminary applied in nutrition management of peach.In our previous research,we found that there was higher root tensity nearby the controlled bag and maintain root activity for a long time,the tree kept median vigour after fertilizer application,and the fruit was uniform.But how the bag controlled-release fertilizer regulate the development of peach tree and the regulation mechanism is still not clear.Pot cultivation combined with field cultivation was used to study the effects of bag controlled-release fertilizer on peach root growth dynamics,and nitrogen absorption and distribution and discuss the regulation mechanism of bag controlled-release fertilizer to the developmemt of peach tree.In order to regulate organ development and nitrogen polar partitioning by changing the nitrogen supply mode to provide the theoretical basis was studied.The main results are as follows:Pot culture experiment showed that the nitrogen utilization rate of bag controlled-release fertilizer treatment was 12.96% and 4.60% of fertilizer spread application treatment after shoots stop growing.Nitrogen partitioning between new shoot of upper and downer part had great difference.The difference of bag controlled-release fertilizer treatment is significantly lower than that of fertilize spread application.The ratio of nitrogen partitioned to storage organ of bag controlled-release fertilizer treatment is significantly higher than that of fertilize spread application after defoliation.The result of field culture experiment of 4 years old peach tree with 15 N isotope tracer technique showed that: the nitrogen use efficiency was 22.80%and 12.63% of bag controlled-release fertilizer treatment and spread application treatment when the trees were destructively separated after defoliation.The root was the main partition organ,the partitioning rate of root was 43.64% and 37.15% of bag controlled-release fertilizer treatment and spread application treatment,and different significantly.The sampling result of growth period indicate that nitrogen deprived from fertilizer of fruit is higher than new shoots,the upper part and outer part of nitrogen deprived from fertilizer of fruit and new shoots is higher than downer and inner part.The difference of the same organ at different part of canopy was lower of bag controlled-release fertilizer treatment than spread application treatment.Compared with split spread application,bag controlled-release fertilizer increasedthe nitrogen usage rate,decreased the nitrogen partitioning difference between growth center and non-growth center,and increased the ratio of nitrogen partitioned to storage organ.The difference of distribution of absorbed nitrogen between different part of canopy depressed as the use of bag controlled-release fertilizer,and the polar distribution characteristic decreased.Pot culture experiment showed that the germination rate and branching rate of bud distributed at different part of canopy were different,showed obviously polar characteristic.The germination rate and branching rate of inner and downer part was significantly higher than other treatments.The total length of new shoot and amount and length and mean internode length of lateral shoot of bag controlled-release fertilizer treatment is the higher than other treatments significantly of the second year.The leaf biomass per area reached58.4g/m~2 and 66.2 g/m~2 of bag controlled-release fertilizer treatment of the two years and is significantly higher than other treatments.The new shoot growth rate of bag controlled-release fertilizer treatment is higher than other treatments of the second year of the experiment at filed cultivation.The node of the first lateral shoot occurred of bag controlled-release fertilizer treatment is lower than other treatments significantly.The ratio of long hard axis of bag controlled-release fertilizer treatment is higher than other treatments and the ratio of short axis is lower than other treatments.The germination rate of inner part of canopy was affected of fertilization method;bag controlled-release fertilizer treatment is higher than other treatments.The mean fruit number and single fruit biomass and mean yield per tree of bag controlled-release fertilizer treatment was increased significantly.The use of bag controlled-release fertilizer increased new shoot growth,extended the time of high growth stage of new shoot,increased the node of new shoot,decreased the polar growth,changed shoots type and decreased lateral shoot occurred node,promoted the growth of lateral shoots,and promoted spring leaves growth.It increased yield of per tree by promoted new shoot growth development and fruit development and leaves development.Two years old peach fine root growth dynamics were monitored by the minirhizotron method for four consecutive years.The result showed that the use of bag controlled-release fertilizer increased the number of fine root.Roots were mainly produced in summer and autumn.The period of time until a root became pigmented was 57 days,38 days and 22 days of bag controlled-release fertilizer treatment,spread application treatment and control,respectively.The median root lifespan was 140 days,110 days and 95 days of bag controlled-release fertilizer treatment,spread application treatment and control,respectively.The root standing crop was increased of bag controlled-release fertilizer treatment,thenumber was higher than 200 every year of the experiment.The root turnover rate was decreased of bag controlled-release fertilizer treatment.The root activity of bag controlled-release fertilizer treatment was significantly higher than other treatments,and reached 41.32mg/g/h.The protect enzyme activity of bag controlled-release fertilizer treatment were significantly higher than other treatments and malondialdehyde concentration of root were significantly lower than other treatments in the middle and late growth period;however,there was no significant difference between spread application treatment and control in the late growth period.It is evidenced from the above that the use of bag controlled-release fertilizer increased the number of fine root,extended the period of time until a root became pigmented,increased the median root lifespan and standing crop,decreased the root turnover rate,and increased the root activity in the growth season.A 3-year located field experiment were conducted to evaluate the effects of bag controlled-release fertilzer on the peach new shoot growth and yield and fruit quality at Pingu,Meixian and Qin'an of China.Compared with traditional fertilizer spread application,bag controlled-release fertilizer treatment significantly decreased the amount of fertilizer usage and the yield and quality of peach without its influence in Pinggu peach production area with higher fertilize use.Bag controlled-release fertilizer decreased the fertilizer rate 1/3,increased the yield and improved the growth status comaprcd with traditional fertilizer spread application.