Application of phosphorus addition in growth and nutrient absorption of dipsacus angulatus

Abstract

The invention belongs to the technical field of agro-ecology, and particularly relates to application of a phosphorus additive in growth and nutrient absorption of dipsacus angulatus, and the addition amount of the phosphorus is 6.5 g / m < 2 >. The nutrient absorption refers to at least one of the following steps: reducing the nitrogen-phosphorus ratio of the pholiota cantoniensis and reducing the nitrogen-phosphorus ratio of the pholiota cantoniensis; the carbon-phosphorus ratio of the pholiota cantoniensis is reduced; the nitrogen absorption amount of the siberian wildginger is increased; and the phosphorus uptake amount of the pholiota cantoniensis is improved. The phosphorus is added to promote the growth of the overground part and the growth of the root system of the awnless cryptotaenia, and the growth of the overground part is that the plant height of the awnless cryptotaenia is promoted to be increased in the early stage of growth, and the tiller number and the leaf number of the awnless cryptotaenia are increased in the middle and later stages of growth; the root growth is promoted mainly by increasing the root length, the root volume and the root area of the awninghamia lanceolata. According to the invention, the phosphorus is added to promote the growth of the awninggloryvine, which indicates that the growth of the awninggloryvine is seriously limited by phosphorus.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of agricultural ecology, and particularly relates to application of phosphorus addition in growth and nutrient absorption of Achnatherum splendens. BACKGROUND

[0002] The limitation of nutrients on terrestrial ecosystem productivity and nutrient cycling is universal, and nitrogen and phosphorus are two essential limiting elements in the process of plant growth, whether alone or in combination. Human activities and fertilizer application have increased the input of nitrogen and phosphorus to biomass. Atmospheric nitrogen deposition has increased by 3 times compared with before industrialization, and may continue to increase in the future. Terrestrial ecosystems are limited by nitrogen and phosphorus, and research shows that nitrogen and phosphorus addition will affect ecosystem productivity, root architecture, soil enzyme activity, microbial biomass and community composition. If phosphorus is not a limiting factor, nitrogen addition will promote plant growth, although high nitrogen will reduce species diversity and ecosystem stability. However, as nitrogen deposition and exogenous nitrogen cause the nitrogen limitation in terrestrial ecosystems to gradually change to phosphorus limitation or nitrogen and phosphorus co-limitation, research shows that the global phosphorus-limited area is gradually increasing.

[0003] Desert steppe ecosystems are generally limited by nitrogen and phosphorus, and traditional fertilization techniques focus on nitrogen fertilizer application, but long-term nitrogen deposition exacerbates soil acidification and reduces species diversity. In the prior art, the amount of phosphorus fertilizer and the ratio of nitrogen fertilizer lack pertinence, resulting in low utilization rate of phosphorus fertilizer by Achnatherum splendens and affecting the growth state of Achnatherum splendens. Therefore, there is an urgent need for a new fertilization strategy for Achnatherum splendens based on plant-soil interaction. SUMMARY

[0004] The purpose of the present application is to provide a kind of phosphorus addition in the application of Achnatherum splendens growth and nutrient absorption, solve the problems existing in the prior art.

[0005] The technical scheme adopted by the present application is: The present application provides a kind of phosphorus addition in the application of Achnatherum splendens growth and nutrient absorption, the amount of phosphorus addition is 6.5g / m 2 ; The nutrient absorption refers to at least one of: 1) reducing the nitrogen-phosphorus ratio of Achnatherum splendens; 2) reducing the carbon-phosphorus ratio of Achnatherum splendens; 3) increasing the nitrogen absorption amount of Achnatherum splendens; 4) increasing the phosphorus absorption amount of Achnatherum splendens.

[0006] Preferably, the nitrogen-phosphorus ratio is at least one of the above-ground nitrogen-phosphorus ratio, root nitrogen-phosphorus ratio and plant nitrogen-phosphorus ratio; The carbon-phosphorus ratio is at least one of the above-ground carbon-phosphorus ratio, root carbon-phosphorus ratio and plant carbon-phosphorus ratio. The nitrogen uptake is at least one of the aboveground nitrogen uptake, the root nitrogen uptake and the plant nitrogen uptake. The phosphorus uptake is at least one of the aboveground phosphorus uptake, the root phosphorus uptake and the plant phosphorus uptake.

[0007] Preferably, the phosphorus addition is applied to the smooth bromegrass in the form of potassium dihydrogen phosphate.

[0008] Preferably, the growth of the smooth bromegrass refers to the improvement of the biomass of the smooth bromegrass.

[0009] Preferably, the biomass includes at least one of the following: 1) the aboveground biomass; 2) the root biomass; 3) the plant biomass.

[0010] Preferably, the phosphorus aboveground biomass is at least one of the plant height, the leaf number and the tiller number.

[0011] Preferably, the root biomass is at least one of the root length, the root volume and the root surface area.

[0012] Preferably, the phosphorus addition can also be used in combination with nitrogen.

[0013] Preferably, the amount of the added nitrogen is 9.36g / m 2 .

[0014] Preferably, the nitrogen is added in the form of urea.

[0015] Compared with the prior art, the present application has the following beneficial effects: The present application provides an application of phosphorus addition in the growth and nutrient absorption of smooth bromegrass, wherein the amount of the phosphorus addition is 6.5g / m 2 ; the amount of the phosphorus addition is 6.5g / m 2The nutrient absorption refers to at least one of the following: 1) reducing the nitrogen-to-phosphorus ratio of *Cryptocoryne spp.*; 2) reducing the carbon-to-phosphorus ratio of *Cryptocoryne spp.*; 3) increasing the nitrogen uptake of *Cryptocoryne spp.*; 4) increasing the phosphorus uptake of *Cryptocoryne spp.*. In this invention, phosphorus addition promotes the growth of both the aboveground parts and the roots of *Cryptocoryne spp.* Aboveground growth is achieved by increasing plant height in the early growth stage, and by increasing the number of tillers and leaves in the middle and later stages of growth. Root growth is promoted primarily by increasing root length, root volume, and root area. The phosphorus addition in this invention promotes the growth of *Cryptocoryne spp.*, indicating that the growth of *Cryptocoryne spp.* is severely limited by phosphorus. In this invention, the nitrogen-to-phosphorus ratio of the aboveground, root, and plant parts of *Cryptocoryne spp.* without phosphorus fertilizer was higher than 16, while the nitrogen-to-phosphorus ratio under phosphorus fertilizer application was lower than 16, and even lower than 14 under combined nitrogen and phosphorus application. This indicates that phosphorus addition alleviated the limitation of phosphorus on *Cryptocoryne spp.*, and this invention has guiding significance for the application of phosphorus fertilizer to *Cryptocoryne spp.*

[0016] In this invention, the soil fertility is low. When phosphate fertilizer is added, the content of available phosphorus in the soil that can be used by plants increases, which accelerates the absorption of phosphorus by the roots and the physiological and biochemical processes of plants. The efficiency of metabolism, transport and storage in plants is improved, which ultimately leads to an increase in the absorption of nitrogen and phosphorus in plants and a rapid accumulation of biomass.

[0017] The interaction between plants and soil plays a crucial role in regulating plant growth and absorption, and the availability of nitrogen and phosphorus nutrients in the soil is an important measure of plant nutrient uptake. The results of this invention indicate that phosphorus treatment significantly increased the content of Olsen-P in the soil, because the addition of exogenous phosphorus directly increased the soil's phosphorus pool and phosphorus availability. Attached Figure Description

[0018] Figure 1 The effects of different nitrogen levels on the growth of *Cryptocoryne argentea* were investigated. a and b represent the plant height of *Cryptocoryne argentea* after 60 and 90 days of planting, respectively; c and d represent the number of leaves of *Cryptocoryne argentea* after 60 and 90 days of planting, respectively; e and f represent the number of tillers and SPAD value of *Cryptocoryne argentea* after 90 days of planting, respectively.

[0019] Figure 2 To illustrate the effects of different fertilization methods on the growth of *Cryptocoryne spp.*, a~c represent the plant height of *Cryptocoryne spp.* after 30, 60, and 90 days of planting, respectively; d~f represent the number of leaves of *Cryptocoryne spp.* after 30, 60, and 90 days of planting, respectively; and g~i represent the number of tillers of *Cryptocoryne spp.* after 30, 60, and 90 days of planting, respectively.

[0020] Figure 3Effects of different nitrogen levels on biomass of Cleistogenes squarrosa, a~d represent aboveground biomass, root biomass, total biomass and root-shoot ratio of Cleistogenes squarrosa at harvest time.

[0021] Figure 4 Effects of different fertilization methods on biomass of Cleistogenes squarrosa, a~d represent aboveground biomass, root biomass, total biomass and root-shoot ratio of Cleistogenes squarrosa at harvest time.

[0022] Figure 5 Effects of different nitrogen levels on plant nutrients of Cleistogenes squarrosa, a~c represent nitrogen concentration, carbon concentration and carbon-nitrogen ratio of aboveground part of Cleistogenes squarrosa at harvest time; d~f represent nitrogen concentration, carbon concentration and carbon-nitrogen ratio of root system of Cleistogenes squarrosa at harvest time; g~i represent nitrogen concentration, carbon concentration and carbon-nitrogen ratio of plant of Cleistogenes squarrosa at harvest time.

[0023] Figure 6 Effects of different fertilization methods on plant nutrients of Cleistogenes squarrosa, a~c represent nitrogen concentration, carbon concentration and carbon-nitrogen ratio of aboveground part of Cleistogenes squarrosa at harvest time; d~f represent nitrogen concentration, carbon concentration and carbon-nitrogen ratio of root system of Cleistogenes squarrosa at harvest time; g~i represent nitrogen concentration, carbon concentration and carbon-nitrogen ratio of plant of Cleistogenes squarrosa at harvest time.

[0024] Figure 7 Effects of different fertilization methods on carbon-nitrogen ratio, nitrogen-phosphorus ratio and carbon-phosphorus ratio of Cleistogenes squarrosa, a~c represent carbon-nitrogen ratio of aboveground part, root system and plant of Cleistogenes squarrosa at harvest time; d~f represent nitrogen-phosphorus ratio of aboveground part, root system and plant of Cleistogenes squarrosa at harvest time; g~i represent carbon-phosphorus ratio of aboveground part, root system and plant of Cleistogenes squarrosa at harvest time.

[0025] Figure 8 Effects of different nitrogen levels and different fertilization methods on nitrogen and phosphorus nutrient absorption of Cleistogenes squarrosa, a: nitrogen absorption amount of Cleistogenes squarrosa at harvest time in different nitrogen levels; b, c represent nitrogen absorption amount and phosphorus absorption amount of Cleistogenes squarrosa at harvest time in different fertilization methods.

[0026] Figure 9 Effects of different nitrogen levels on root system traits of Cleistogenes squarrosa, a~f represent root length, root surface area, root diameter, root volume, specific root length and root tissue density of root system of Cleistogenes squarrosa at harvest time.

[0027] Figure 10 Effects of different fertilization methods on root system traits of Cleistogenes squarrosa, a~f represent root length, root surface area, root diameter, root volume, specific root length and root tissue density of root system of Cleistogenes squarrosa at harvest time.

[0028] Figure 11 Effects of different nitrogen addition levels on soil nutrients of Aneurolepidium sinuatum, a~f represent soil ammonium nitrogen, soil nitrate nitrogen, soil total inorganic nitrogen, Olsen P content, microbial biomass nitrogen and microbial biomass carbon after 90 days of nitrogen addition, respectively.

[0029] Figure 12 Effects of different fertilization methods on soil nutrients of Aneurolepidium sinuatum, a~d represent soil total carbon, soil total nitrogen, soil carbon-nitrogen ratio and Olsen P content after 90 days of nitrogen and phosphorus addition, respectively.

[0030] Figure 13 Effects of different nitrogen addition levels and different fertilization methods on soil pH of Aneurolepidium sinuatum, a and b represent soil pH after 90 days of nitrogen addition and nitrogen and phosphorus addition, respectively.

[0031] Figure 14 Results of the greenhouse test, A~D represent CK group, single nitrogen fertilizer group, single phosphorus fertilizer group and nitrogen and phosphorus co-application group, respectively. DETAILED DESCRIPTION

[0032] The present application will be further described in the following specific examples, but it does not limit the scope of the present application. The details and forms of the technical solutions of the present application can be modified or replaced without departing from the spirit and scope of the present application, and these modifications or replacements all fall within the protection scope of the present application.

[0033] The inventive concept of the present application is as follows: The present application proves that nitrogen addition does not change the plant height, leaf number, tillering and biomass of Aneurolepidium sinuatum, which indicates that it does not respond to N addition as assumed. Continuous N addition does not change the growth of perennial grasses such as Aneurolepidium sinuatum in natural systems, even reaching 100 kg / ha / yr in the field test in 2016. In many studies, the N addition rate can be as high as 200 kg / ha / yr, which leads to changes in the growth of some plants. Therefore, it is guessed that Aneurolepidium sinuatum may also have the same promoting effect if exposed to higher N addition, but it is difficult to achieve such a high N deposition rate in the desert steppe. In addition, studies have shown that different functional group species have different sensitivities to nitrogen addition. Generally, exogenous nitrogen addition is more beneficial to annual and biennial plants, which is mainly due to their species characteristics, including their rich seed yield, fast growth and high height. In contrast, perennial plants have conservative resource utilization strategies, including a large root-shoot ratio and carbon-nitrogen ratio, high water use efficiency and high non-structural carbohydrate reserves in the root system, and legumes do not depend on nitrogen due to their excellent nitrogen fixation. These results show that nitrogen enrichment is beneficial to nitrogen-loving species with acquisitive resource utilization strategies, rather than those with conservative resource utilization strategies.

[0034] The phosphorus addition in the present invention promoted the growth of aboveground part of Puccinellia tenuiflora, and this promoting effect of phosphorus addition indicated that the growth of Puccinellia tenuiflora was severely limited by phosphorus. The ratio of nitrogen to phosphorus can represent the relative nutrient limitation of plant growth. Previous studies showed that when the ratio of nitrogen to phosphorus was greater than 16, the plant was limited by phosphorus at the level of plant, when the ratio of nitrogen to phosphorus was less than 14, the plant was limited by nitrogen, and when the ratio of nitrogen to phosphorus was between 14 and 16, the plant was limited by both nitrogen and phosphorus. In the present invention, the ratio of nitrogen to phosphorus of aboveground part, root and plant of Puccinellia tenuiflora without phosphorus addition were all higher than 16, while the ratio of nitrogen to phosphorus with phosphorus addition were all less than 16, and even less than 14 with nitrogen and phosphorus addition, which indicated that the phosphorus addition alleviated the limitation of phosphorus on Puccinellia tenuiflora.

[0035] The phosphorus addition in the present invention promoted the growth of aboveground part and root system, in which the aboveground part promoted the increase of plant height in early growth stage, and promoted the increase of tiller number and leaf number in middle and late growth stage; the root system promoted the growth mainly through the increase of root length, root volume and root area. Consistent research results were reported in many grassland plants, such as Poa annua and switchgrass, because phosphorus, as an essential nutrient element for plant growth and development, played an important role in improving photosynthetic efficiency and increasing plant tillering. In addition, the soil fertility in the present invention was low, and the available P content in soil increased after adding phosphorus, which accelerated the absorption of phosphorus by root system and the physiological and biochemical action of plant, and improved the metabolic and transport storage efficiency in plant, finally leading to the increase of nitrogen and phosphorus absorption and rapid accumulation of biomass in plant.

[0036] The low nitrogen addition in the present invention did not change the soil inorganic nitrogen content, while the nitrogen addition increased the soil microbial biomass nitrogen, and it was guessed that the increased nitrogen in low nitrogen treatment made up the absorption of nitrogen by soil microorganisms. The field experiment in desert grassland also proved that the nitrogen addition increased the soil microbial biomass nitrogen. However, the soil microbial biomass nitrogen remained unchanged under high nitrogen addition, and the soil inorganic nitrogen content increased significantly, which was because the absorption of nitrogen by microorganisms reached saturation when the nitrogen addition was 30 kg / ha / yr, so it was guessed that 30 kg / ha / yr was the threshold of microbial nitrogen addition. The high nitrogen reduced the soil pH, which was because the nitrogen addition reduced the content of base ions such as Mg 2+ and K + in soil, and increased the content of acid base ions such as Mn 2+ and Al 3+ , so the higher the nitrogen addition, the more serious the soil acidification. Consistent results were obtained in the nitrogen and phosphorus addition experiment, and phosphorus had almost no effect on soil pH.

[0037] As the main dominant species of desert steppe, the indoor test of the present application shows that the A. frigida adopts a conservative utilization strategy to nitrogen addition and is not sensitive to different levels of nitrogen addition. However, phosphorus addition promotes the growth and nutrient absorption of A. frigida, indicating that A. frigida is limited by phosphorus.

[0038] In order to enable the technical personnel in the art to better understand the technical solutions of the present application and to implement them, the present application will be further described below in conjunction with specific embodiments. In the description of the present application, if not specially stated, the reagents used are commercially available, and the methods used are conventional techniques in the art.

[0039] Example 1 The application of phosphorus addition in the growth and nutrient absorption of A. frigida is as follows: 1. Materials and methods.

[0040] 1.1 Test design.

[0041] The present application is carried out in the artificial climate chamber of the College of Grassland and Resource Environment of Inner Mongolia Agricultural University, the illumination time is 16h, the illumination intensity is 500μmol / (m 2 ·s), the indoor temperature and humidity are artificially controlled, the temperature is 30℃, and the humidity is 60%. The plant seeds and required soil are collected from the desert steppe of Siziwang Banner in Ulanqab City, Inner Mongolia Autonomous Region. The present application selects the dominant C4 grass-A. frigida of desert steppe, and the collected seeds are mature seeds that are about to fall off at the end of the 2022 growing season, and the thousand seed weight is 0.2g. The soil type is chestnut soil, the soil pH is 8.3, the field water capacity is 23%, the total nitrogen content of the soil is 1.44g / kg, the ammonium nitrogen content is 4.36mg / kg, the nitrate nitrogen content is 27.84mg / kg, and the available phosphorus content is 7.4mg / kg. Before planting, visible impurities are removed by a soil sieve with a diameter of 2mm. Before the test, the seeds are sterilized in hydrogen peroxide with a volume percentage of 30% for 5min, washed with deionized water, and then placed in a saturated calcium sulfate solution to promote seed germination. The treated seeds are placed in a culture dish with a diameter of 120mm, the culture dish contains two layers of moist qualitative filter paper, and the A. frigida seeds are placed in a 33.7℃ incubator for germination. The germination rate of A. frigida is 87.5%.

[0042] The present application is divided into two greenhouse tests, both of which adopt a single factor complete random factor design.

[0043] The first greenhouse test sets 5 different nitrogen levels, with the addition of nitrogen being 0 kg / ha, 10 kg / ha, 20 kg / ha, 30 kg / ha and 50 kg / ha, with 4 repeats for each treatment. According to the 3:7 deposition ratio of organic nitrogen and inorganic nitrogen in the desert steppe, and the 1.63:1 deposition ratio of ammonium nitrogen and nitrate nitrogen in inorganic nitrogen, the nitrogen is added, wherein the organic nitrogen is replaced by urea, the ammonium nitrogen is replaced by ammonium bicarbonate NH4HCO3, and the nitrate nitrogen is replaced by calcium nitrate Ca(NO3)2.

[0044] The second greenhouse test is divided into 4 different fertilization methods, namely the CK group without fertilization, the single nitrogen fertilizer group, the single phosphorus fertilizer group and the nitrogen and phosphorus co-application group. The single nitrogen fertilizer group adds 9.36 g / m 2 of nitrogen; the single phosphorus fertilizer group adds 6.5 g / m 2 of phosphorus; and the nitrogen and phosphorus co-application group adds 9.36 g / m 2 of nitrogen and 6.5 g / m 2 of phosphorus. In the present application, the nitrogen is added in the form of urea, and the phosphorus is added in the form of potassium dihydrogen phosphate. Each treatment has four repeats, for a total of 16 pots. Since the experiment is carried out in a flowerpot, the amount of nitrogen can be converted to 36 mg / kg; the amount of phosphorus is 25 mg / kg.

[0045] The nitrogen fertilizer and phosphorus fertilizer are dissolved in deionized water according to the above different treatment conditions and fully mixed with 1.5 kg of air-dried soil, and then loaded into a flowerpot. After the seeds of Aneurolepidium chinense appear to have germinated, they are buried 3 cm from the soil surface, with 11 seeds per pot. The soil moisture content is maintained at 70% of the soil field water capacity, and is added every other day. When the plants grow to 6 cm, the seedlings are transplanted, with 3 seedlings per pot. The plants are harvested after 90 days of planting.

[0046] 1.2 Determination items and methods.

[0047] 1.2.2 Plants and harvesting.

[0048] The plant growth index is determined by measuring the plant growth characteristics, including plant height, leaf number and tillering, at 30 days, 60 days and 90 days of planting.

[0049] The shoots and roots of the plants were harvested and oven-dried at 70 °C to constant weight to obtain the aboveground and root biomass. To analyze the root architecture, the roots were scanned and analyzed using WinRHIZO software to obtain root traits, including root length, root surface area, root volume, root diameter, specific root length, and root tissue density. The specific root length is the ratio of root length to root biomass, and the root tissue density is the ratio of root biomass to root volume. The shoots, roots, and soil were ground to analyze the plant carbon, nitrogen, and phosphorus concentrations. The plant nutrient content and uptake include the total carbon, nitrogen, and phosphorus content of the shoots and roots. The soil nutrient content includes the total carbon content, total nitrogen content, available phosphorus content, and soil pH. The carbon and nitrogen concentrations of the plants and soil were determined using an elemental analyzer, the total phosphorus concentration of the plants was determined using the molybdenum-antimony anti-colorimetric method, and the plant nitrogen and phosphorus content was the product of the biomass and the nitrogen and phosphorus concentrations. The soil available phosphorus content was determined by the sodium bicarbonate method (Olsen method), and the soil pH was determined using a pH meter.

[0050] 1.3 Statistical analysis.

[0051] One-way ANOVA was used to analyze the effects of different planting times, different nitrogen addition levels, and different fertilization treatments on the growth traits of P. kamoji, biomass, nutrient uptake, and soil physical and chemical properties at harvest. Correlation analysis was used to explore the key factors affecting biomass and nutrient uptake.

[0052] 2. Results and analysis.

[0053] 2.1 Effects of nitrogen and phosphorus addition on plant growth.

[0054] The first greenhouse experiment, i.e., the addition of five different nitrogen levels, showed that different levels of nitrogen addition did not change the growth traits of P. kamoji, including plant height, leaf number, tillering, and SPAD value, compared with no nitrogen application, as shown in Table 1, P > 0.05. With the increase of planting time, the plant height and leaf number reached the maximum at harvest. The plant height grew slowly after 60 days, while the leaf number increased rapidly from 4 to 22 pieces from 60 to 90 days. The aboveground biomass and root biomass of P. kamoji at harvest were 1.16 g / pot and 0.20 g / pot, respectively, and there was no difference between different nitrogen levels, as shown in Table 2, P > 0.05. Different levels of nitrogen addition had a significant effect on root volume, which was significantly higher at 20 kg / ha than at 10 kg / ha, 30 kg / ha, and 50 kg / ha. In addition, root length, root diameter, root surface area, root tissue density, and specific root length did not respond to nitrogen addition, as shown in Table 3, P > 0.05. Figure 1 Figure 3 Figure 9

[0055] ​​​The second greenhouse experiment, i.e. four different fertilization modes, the results are as follows, different fertilization modes significantly changed the growth of E. gigantea. Compared with no fertilization, single nitrogen fertilizer group did not change the growth of E. gigantea; while single phosphorus fertilizer group significantly promoted the aboveground biomass, root biomass and plant biomass of E. gigantea. In the first 60 days, it mainly increased the plant height, and after 60 days, it increased the tiller number and leaf number, see Figure 2 , P<0.05. Compared with no fertilization, the plant biomass of single phosphorus fertilizer group increased by 40.41% at harvest; the plant biomass of nitrogen and phosphorus co-application treatment increased by 48.64% at harvest. The phenotype diagram is shown in Figure 14 .

[0056] The root-shoot ratio did not change under different nitrogen level addition and different fertilization modes, the root-shoot ratio of different nitrogen level addition was 0.17; the root-shoot ratio of different fertilization modes was 0.14, see Figure 3 and Figure 4 .

[0057] Different fertilization modes had different effects on the root traits of E. gigantea, among which, compared with no fertilization, single phosphorus and nitrogen and phosphorus co-application treatments significantly increased the root length, root volume and root surface area of E. gigantea, while the root diameter, specific root length and root tissue density were not affected by the fertilization mode, see Figure 10 .

[0058] 2.2 Effects of different fertilization modes on plant absorption.

[0059] Different levels of nitrogen addition had no effect on the nitrogen concentration and carbon-nitrogen ratio of E. gigantea. The aboveground nitrogen concentration, root nitrogen concentration and plant nitrogen concentration of E. gigantea were 2.58%, 1.47% and 2.36%, respectively. The aboveground carbon-nitrogen ratio, root carbon-nitrogen ratio and plant carbon-nitrogen ratio were 15.24, 37.00 and 16.82, respectively. The aboveground carbon concentration, root carbon concentration and plant carbon concentration of E. gigantea responded significantly to nitrogen addition, all showing the highest at high nitrogen levels of 300 kg / ha and 50 kg / ha, see Figure 5 , P>0.05.

[0060] Different fertilization modes had no effect on the nitrogen concentration of E. gigantea, but significantly changed the carbon concentration and phosphorus concentration of E. gigantea. Compared with no fertilization, fertilization reduced the carbon concentration of E. gigantea, while phosphorus-containing treatments significantly increased the phosphorus concentration of the plant; among them, the phosphorus concentration of single phosphorus and nitrogen and phosphorus co-application treatments increased by 27.46 and 67.28% compared with no fertilization, see Figure 6 .

[0061] Compared with no fertilization, single N fertilizer did not change the N:P ratio in shoots, roots and whole plants, while single P fertilizer and NP combined significantly decreased the N:P ratio and C:P ratio. Under no fertilization and single N fertilizer, the N:P ratio in shoots, roots and whole plants of L. chinensis were all higher than 16, while under single P fertilizer, the N:P ratio were all lower than 16. The N:P ratio in shoots, roots and whole plants of L. chinensis were 15.32, 11.47 and 14.98, respectively, in which the N:P ratio in shoots and whole plants were between 14 and 16, while the N:P ratio in roots were lower than 14. Under NP combined, the N:P ratio in shoots, roots and whole plants were 11.84, 12.51 and 11.85, respectively, all of which were lower than 14, see Figure 7 .

[0062] There were no differences in the N uptake in shoots, roots and whole plants among different levels of N addition, which were 30.19 mg / pot, 2.28 mg / pot and 32.47 mg / pot, respectively. There were significant differences in the N and P uptake among different fertilization treatments. The N uptake in shoots, roots and whole plants under NP combined and single P fertilizer were significantly higher than that under no fertilization and single N fertilizer. The P uptake in shoots, roots and whole plants under NP combined and single P fertilizer were also significantly higher than that under no fertilization and single N fertilizer.

[0063] Under single P fertilizer, the N uptake in shoots, roots and whole plants were 78.62 mg / pot, 5.54 mg / pot and 84.16 mg / pot, respectively. Under NP combined, the N uptake in shoots, roots and whole plants were 85.21 mg / pot, 5.22 mg / pot and 90.43 mg / pot, respectively. Compared with no fertilization, the P uptake in shoots under two P-containing fertilization treatments were significantly increased by 71.50% and 149.35%, respectively. The P uptake in roots were increased by 133.60% and 99.10%, respectively. The total P uptake in whole plants were 5.70 mg / pot and 7.99 mg / pot, respectively, see Figure 8 .

[0064] 2.3 Effects of different fertilization methods on soil physicochemical properties.

[0065] Different levels of N addition had significant effects on soil nitrate N, inorganic N, microbial biomass N and soil pH. Soil nitrate N and inorganic N contents were significantly increased under 50 kg / ha high N level. Soil microbial biomass N was significantly increased after N addition, and was the highest under high N level. Compared with no N addition, 10 kg / ha N addition did not change soil pH, while soil pH was significantly decreased with the increase of N addition, and decreased by 0.06 units under 50 kg / ha, seeFigure 13 Nitrogen addition had no effect on soil ammonium nitrogen, soil microbial biomass carbon and Olsen-P content. However, fertilization methods significantly changed soil Olsen-P content and soil pH. Compared with no fertilization, single nitrogen fertilizer did not change soil Olsen-P content, single phosphorus and nitrogen-phosphorus co-application significantly increased soil phosphorus content by 50.83% and 67.00%, respectively. The soil Olsen-P content under no fertilization, single nitrogen fertilizer, single phosphorus and nitrogen-phosphorus co-application was 8.67 mg / kg, 8.85 mg / kg, 13.08 mg / kg and 14.48 mg / kg, respectively, as shown in Table 2. Figure 12 Soil pH was significantly different under different fertilization methods. Compared with no fertilization, single nitrogen fertilizer significantly reduced soil pH, while no fertilization, single phosphorus and nitrogen-phosphorus co-application had no significant difference, as shown in Table 2. Figure 13 Soil total nitrogen, total carbon content and carbon-nitrogen ratio were not significantly different under different nitrogen addition and fertilization methods. The average soil nitrogen content was 1.62 g / kg, and the average soil carbon content was 15.14 g / kg.

[0066] The technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present disclosure.

[0067] The above-described embodiments only express several embodiments of the present application, which are described in detail and specifically, but should not be understood as limiting the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of the present application.

Claims

1. Use of phosphorus addition in growth and nutrient uptake of Puccinellia distans, characterized in that, The amount of the phosphorus addition is 6.5 g / m 2 ; The nutrient uptake refers to at least one of: 1) reducing the nitrogen to phosphorus ratio of the elsholtzia humilis; 2) reducing the carbon to phosphorus ratio of the elsholtzia humilis; 3) increasing the nitrogen uptake of the elsholtzia humilis; 4) increasing the phosphorus uptake of the elsholtzia humilis.

2. Use according to claim 1, wherein The nitrogen to phosphorus ratio is at least one of the above-ground nitrogen to phosphorus ratio, the root nitrogen to phosphorus ratio and the plant nitrogen to phosphorus ratio; The carbon to phosphorus ratio is at least one of the above-ground carbon to phosphorus ratio, the root carbon to phosphorus ratio and the plant carbon to phosphorus ratio; The nitrogen uptake is at least one of the above-ground nitrogen uptake, the root nitrogen uptake and the plant nitrogen uptake; The phosphorus uptake is at least one of the above-ground phosphorus uptake, the root phosphorus uptake and the plant phosphorus uptake.

3. The use according to claim 1, wherein The phosphorus addition is in the form of potassium dihydrogen phosphate.

4. The use according to claim 1, wherein The elsholtzia humilis growth refers to increasing the biomass of the elsholtzia humilis.

5. The use according to claim 4, wherein the compound is ###00002### The biomass includes at least one of: 1) the above-ground biomass; 2) the root biomass; 3) the plant biomass.

6. The use according to claim 5, wherein the compound is ###0002### The above-ground biomass is at least one of the plant height, the leaf number and the tiller number.

7. The use according to claim 5, wherein the compound is ###0002### The root biomass is at least one of the root length, the root volume and the root surface area.

8. The use according to claim 1, wherein The phosphorus addition can also be used in combination with nitrogen.

9. Use according to claim 8, wherein the compound is ###0002### The amount of nitrogen added is 9.36 g / m 2 .

10. The use according to claim 8, wherein the compound is ###0002### The nitrogen is in the form of urea.

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