Effects Of Exogenous Nitrogen And Potassium On The Growth And Nutrients Uptake Of Festuca Arundinacea

The issue of urban landscaping has received great attention with the acceleration of urbanization,in recent years.Turfgrass is the most widely used green cover plant in China’s garden landscape.Turf maintenance management with reasonable fertilization as the main content is the key to obtaining high quality lawn.In this paper,Festuca Arundinacea was used as the test crop,the effects of different nitrogen and potassium forms and dosages on the growth and nutrient uptake of Festuca Arundinacea were studied by pot experiments,so as to determine the optimum nitrogen and potassium nutrient dosage and provide scientific fertilization for Festuca Arundinacea.The main conclusions are:1,Exogenous nitrogen could promote the growth of plant shoot.The nutrients uptake per unit root length,nutrients accumulation and distribution ratio of plant shoot increased,and the total root length of plant decreased.Nitrogen forms had significant effects on the growth and nutrients absorption characteristics of Festuca Arundinacea.Exogenous ammonium nitrate significantly increased plant height and dry matter accumulation of shoot,and urea was the lowest.The difference in plant height between calcium nitrate and ammonium nitrate treatments was not significant.Ammonium nitrate enhanced the dry matter accumulation of root and total root length,and the average diameter and surface area of the urea treated plants increased.The amount of nutrients uptake of plant shoot and the nutrients uptake per unit root length of ammonium nitrate and calcium nitrate treatments were higher than that of urea,and there were no significant differences between nitrogen forms in the proportion of nutrients distributed in the plant shoot.In summary,ammonium nitrate can promote the growth of plant shoot,followed by calcium nitrate,thus,ammonium nitrate can be used as the preferred nitrogen source for the conservation and management of Festuca Arundinacea.2,The plant height,dry matter accumulation of shoot and root diameter of Festuca Arundinacea increased with exogenous N supply,while,the total root length,root surface area and the root length in the range of<0.3 mm and>0.9 mm root diameter decreased.Compared with 2.5 mM N treatment,the dry matter of shoot,total root length and the root surface area of plants decreased with 10 mM N.With exogenous N increasing,the N and potassium concentrations and N,P,K uptake of shoot increased,meanwhile,the proportion of N and K distributed in the shoot increased.The nutrients concentration in the underground of plant increased with the increasing of exogenous N,no significant difference were found in N,K content of underground between treatments.N and K uptake per unit root length increased by the increasing of N supply,and there was no significant difference in the amount of P uptake per unit root length between 2.5 mM and 10 mM N treatments.Comprehensive analysis in the growth of shoot and root of plants,2.5 mM exogenous N is more conducive to promoting the growth of Festuca Arundinacea,increase nutrients uptake,and save N resources.3,Exogenous NO₃^--N had significant effects on the growth of shoot and root of Festuca Arundinacea.With the increase of NO₃^--N concentration,the plant height and dry matter accumulation of shoot increased first and then decreased.The root dry matter accumulation,root length and root surface area decreased with the increase of NO₃^--N concentration,and the mean root diameter was not statistically different between treatments.Increasing the concentration of NO₃^--N could increase P concentration and P uptake,and the suitable concentration of NO₃^--N could promote the absorption and accumulation of nitrogen and potassium in the shoots.The optimal concentration of NO₃^--N for Festuca Arundinacea’s growth was 4.3-18.2 mM.From the above results,4.3mM NO₃^--N can be used as a reference for the rational N fertilization in Festuca arundinacea conservation and management.4,In the medium and low soil potassium supply levels,when the potassium fertilizer dosage was 300 mg/kg,it could significantly promote the growth and development of the above-and below-ground of Festuca arundinacea,from the plant height,above-and under-ground dry matter accumulation,the effects of soil type and potassium application amount reached significant levels,and the interaction between the two was not obvious.With the increase of potassium fertilizer application,the content of soil available potassium and slow-acting potassium increased.The relative biomass of the plants aboveground was significantly correlated with the amount of potassium fertilizer.According to the 80%of the maximum growth of Festuca arundinacea,the optimum potassium fertilizer application rates for the medium and low potassium soils were 63-374 mg/kg and 79-392mg/kg,respectively.5,In low potassium soil,the soluble sugar content and proline content of plant leaf increased gradually with the increase of K fertilizer application amount.When the K application rate was 400 mg/kg,the leaf soluble sugar content and proline content were significantly higher than that of 0 mg/kg and 200 mg/kg.Treatments with 0 mg/kg and 200mg/kg potash fertilizer application rates showed no significant difference between.The activity of catalase in the leaves increased significantly with the increase of potash fertilizer application,and the K fertilization treatments of 0,200,400 mg/kg reached significant levels.With the increase of fertilization,the content of malondialdehyde in leaves gradually decreased.When the potassium application level was 0 mg/kg,the content of malondialdehyde in the leaves was significantly higher than 200 mg/kg and 400 mg/kg,and the difference reached a significant level.