3.2 Carbon, nitrogen, phosphorus content and stoichiometry of
plant and soil
Fig. 3 Content and stoichiometric characteristics of organic
carbon, total nitrogen, and total phosphorus in plant root and shoot
fractions and rhizosphere soils with different gravel contents. Error
bars refer to standard deviation Different lowercase letters indicate
significant differences among different gravel soils (p<0.05).
As shown in Fig. 3, OC, TN, TP, C: N, C:P, and N:P of different soils
have significant differences(p<0.05). TP of shoot, root and
rhizosphere decreased in the order of low˃medium˃high gravel content; TN
was larger for low than for medium and high gravel contents; organic
carbon content showed no significant difference among different gravel
soils (p˃0.05). C:N of rhizosphere soil was larger for high than for
medium and low gravel contents; TP of shoot and root fractions decreased
in the order of high˃medium˃low gravel content; N:P of shoot and root
fractions was larger for high than for medium and low gravel contents.
Fig. 4. Content and stoichiometric characteristics of organic
carbon, total nitrogen, and total phosphorus in plant root and
aboveground fractions and rhizosphere soils for different plant species.
Error bars refer to standard deviation; respectively. Different
lowercase letters indicate significant differences among different plant
species (p<0.05). Fe, Festuca elata ; Ed, Elymus
dahuricus ; Ms, Medicago sativa ; Fe+Ed, Festuca elata plus
Elymus dahuricus ; Fe+Ms, Festuca elata plus Medicago sativa ;
Ms+Ed, Medicago sativa plus Elymus dahuricus ;Fe+Ms+Ed,Festuca elata plus Medicago sativa plus Elymus dahuricus .
Fig. 4 illustrates the contents and stoichiometric characteristics of
OC, TN and TP of plant shoot, root fractions and rhizosphere soils among
different plant species. For plant shoot fraction, TN content was the
largest and the lowest for Ms (30.76 g kg-1)
and Fe (11.40 g kg-1), respectively; TP content
of Ed (2.23g kg-1), Ms (2.13g
kg-1), Fe+Ed (2.19g kg-1),Fe+Ms (1.81g kg-1), Ed+Ms (1.92g
kg-1) were significantly larger than that of Fe(1.57g kg-1) and Fe+Ed+Ms (1.55g
kg-1); OC content was the lowest for Ms+Ed(422.99 g kg-1) among plant species. C:N was
significantly different (p<0.05), while C:P was not
statistically significant (p˃0.05). N:P of Ms (14.71g
kg-1) and Ms+Ed (14.01g kg-1)
was significantly higher than that of Fe (7.42g
kg-1) and Fe+Ed (8.21g kg-1).
For plant root fraction, TN, TP, C: N, C:P and N:P had significant
differences(p<0.05), among which the OC content of Ms(468.35 g kg-1) and Fe+Ms (469.38g
kg-1) was larger than that of Fe (406.33g
kg-1) and Fe+Ms+Ed (408.22g
kg-1). The OC, TP, C:N and C:P of rhizosphere soils
showed no significant differences among plant species exceptFe+Ms .