全 文 ：文章编号: 1007-0435( 2001) 01-0025-09
生长季羊草割草场刈割胁迫响应
多立安, 赵树兰
(天津师范大学化学与生命科学学院, 天津 300074)
摘要: 生长季内刈割胁迫羊草草原割草场, 结果表明, 胁迫强度与方式对草地主要种群和群落数量特征再生性影
响较大; 胁迫强度增强 ,其数量特征值下降幅度愈大, 再次刈割时间愈后延,则下降愈明显, 尤以羊草为显著, 表明
其耐刈性较差。就产质量而言, 两次刈割可获得较高的牧草和蛋白质产量, 一次或三次刈割则相对次之, 尤其三次
刈割不利影响极大; 过晚利用会降低蛋白质产量, 而影响牧草品质。研究证实,当地传统割草制度极大地浪费了草
地资源, 因此, 要充分挖掘生产潜能,则须改变割草模式,科学利用, 既兼顾产质量要素, 又能保持草地处于良好的
发育状态。
关键词: 刈割胁迫; 羊草草原割草场; 牧草产量; 蛋白质产量; 再生性
中图分类号: S812. 5　　文献标识码: A
Effects on Mowing Grasslands of Leymus chinensis by
the Same Stress in Growing Season
DUO Li-an　ZHAO Shu-lan
( Colleg e of Chemical and L ife Sciences, T ianjin No rmal Univ ersit y, T ianjin, 300074, China)
Abstract: By mow ing st ress mow ing grassland of L . chinensis grassland in g row ing season, the
regenerat ivity o f its main populat ion and community w ere studied. T he results show ed that different
intensity and w ay o f mowing str ess gr eat ly af fected the populat ion and community of herbage. As the
increase of the intensity of mow ing st ress, the value o f quantity character ist ics o f g rassland herbages
populat ion and community dropped increasingly . T he later the date of the second mow ing, the clearer the
dr opping t rend of g row ing potent ial . Especially L . chinensi s population, it s dropping range of g row ing
po tent ial was the bigg est , show ing that L . chinensis populat ion w as short of standing mow ing. From the
yield and quality o f regenerat ive her bage, high y ield of her bage and high total pro tein could be obtained by
mow ing twice, and that came second by mow ing once or three t imes. If the second crop w as used too early
by mow ing tw ice, the y ield o f herbage would be r educed st rikingly. M ow ing three t imes had ex t remely
unfavorable ef fect on L . chinensis populat ion. The first and the second cr op had relat iv ely high protein
content . U sing the grassland to o late w ould also reduce protein content o f herbage, making the herbage
quality drop. Comprehensive analy sis indicated that in order to bring the most product iv e forces of
gr assland into full play , and to g ive considerat ion to the essent ial factors o f bo th yield and quality, as w ell
as to keep the gr assland in good grow ing state and mow ing tw ice a year and ut ilizing ( that w as the
t reatment of July 5 and September 5) tow ards ideal. But w hat w e deserved attent ion w as to lie plant ing
fallow and mowing in turn. If the grassland w as mow ed and ut ilized once a year , the opt imum mow ing t ime
should be extended tow ards the and of July and August 2. U ltimately the study proved that the t raditional
收稿日期: 1999-10-14;修回日期: 2000-11-23
　　作者简介: 多立安,男, 36岁,硕士,副教授,硕士生导师,发表论文 30余篇,获省部级科技进第二、三等奖各 1项,现主持国家自然科学基
金等 4项课题
第 9卷　第 1期
　Vol. 9　　No. 1
草　地　学　报
ACTA AGREST IA SINICA
　2001 年　3 月
March 　2001
system of mow ing and utilizing in the lo ca l area w ould squander the gr assland resources g r eatly . Ther efor e, to t ap the
productiv e po tentialities o f gr asslands fully , t he pattern of their tr aditional mow ing and ut ilizing tr eatments should be
changed.
Key words : M ow ing st ress; Mow ing L eymus chinensi s grasslands; Her bage yield; Yield of crude pr otein;
Regener at ivity
　　The g rassland through using L eymus chinensis
as edificato is a kind o f roo t sto ck grassland study
which is peculiar to the east of subregion in the
middle of Eurasia grassland r eg ion. It s total area is
about 420, 000 squar e kilomit res, among which
w ithin Chinese boundaries, about a half is one of
the main zonal vegetations in no rtheast China. L .
chinensis gr assland is a lush and g reen grow ing
gr assland mainly occupied by L . chinensis, it s
topography is open and smoo th, the herbage
quality is highly-nutrit ive and good in edibility , and
the yield is in the f irst status within temperate
gr assland zone. T hus it is also a very ideal natur al
mow ing grassland. How ever. w hat deserves
at tention to us is that because o f the unreasonable
utilizat ion of L . chinensis grassland in recent years,
the degener ation phenomenon is v ery serious,
especially in our Songnen plain, L . chinensis
gr asslands degenerat ion and salinizat ion is mo re
serious, that making local herbage both y ield and
quality drop too, and inhibit ing the gr assland
development animal indust ry , and its fast
regenerat ivity af ter mowing due to the result of
natural and ar tif icial selection o f plant community,
and it is also an important index for measuring the
current grassland econom ic features For this
reason, some scholar s of our same trade studied
and suggested dif ferent kinds of r eg enerativ ity
pr oblems[ 1～3. 5] . In g eneral, the grassland af fairs
should be stopped ut ilizat ion in the period
w henever unfit ted fo r mow ing, otherw ise the
gr assland prospects w ould be pessim ist ic so on
mor e or less. Mow ing at the most f it ted period can
be enhanced, not only in herbage y ield but also in
pr otein content . Protein content of our g rassland is
also one o f important indexes fo r measur ing
economic values. Therefore, our study had
accumulated gr assland protein dynamics in
different per iods and const ructed impor tant and
different meaning fulnesses
[ 4. 5]
. Our study has also
chosen much examples in the sect ion of L . chinensis
in No rtheast China and studied on lots of
r eg enerative ef fects of grassland dur ing mow ing
st resses. T he aim in the study is to recognize
thoroughly the scient ific features of yield and
quality in format iv e featur es of L . chinensis
g rassland in the grow ing season, and meant imely
prov ide scientif ic bases for eff icient ly ut ilizing and
improving g rassland affairs, and at last establish
good schemes of management .
1 　 The general situation under
natural conditions in experimental
regions and methods
1. 1　Natural conditions
Our exper imental site is in the L . chinensis
g rassland region o f Songnen plain in No rtheast
China, at 45°35′N and 125°7′E. belonging to
temper ate zone and monsoon climate, cont rolled by
the Pacif ic high pr essure reg ion in summer, w ith
w arm and rainy w eathers; and also rest ricted by
the M ongo lian high pressur e in w inter, especial ly
cold and dry. T he annual av erage temperature is 3.
8℃. In the ho ttest month ( July ) , the average
temper ature is 22. 7℃, and w ith the maximum 38.
1℃; in the coolest month( January) , it is - 19. 4℃,
and its m inimum is - 28. 9℃. T he annual average
accumulated temper ature is higher than 10℃,
summing up to about 2800℃. The average annual
sunshine t ime is 2789. 5 hours. The fro st-fr ee
period is ar ound 130 ～ 156 days. The annual
av erage precipitat ion is 490mm, mainly
concentrat ing fr om June to September , and
26 草　地　学　报 第 9卷
occupy ing 81. 8% o f total precipitation in a year. In
w inter, f rom November to M arch, the precipitat ion
tends to the low est , making up to about 3. 7% of
the to tal annual precipitat ion. T he r eg ional so il
st ructure in study slight ly is somewhat alkalized
meadow and the total soil salinity is about 0. 1%,
w ith pH around 8. 16.
1. 2　The general situation of vegetation
The r eg ional vegetat ion studied belongs to the
meadow grassland of L . chinensis. It s edif icato is L .
chinensis, and the main dominant species are
Festuca chelungkiangnica, Cleistogenes squarr osa,
Potentilla f lagellaris. It s main fo rage plant species
are r ich and varied, they are Calamagrost is
ep iqeios, A rundinella hirta, Vicia amoena, L athy rus
quinquenervius, V icia multicaul is, Clemat is
hexap etala, S ophora f lavescens , Taraxacum sinicum , I x er is
chinensis , A nemar rhena asp hodeloid es . So il layer plant s
gr own in ear ly spr ing are Oxy trop is my riop hy lla, V iola
dissecta, V iola p r ionantha, S enecio integ rif olitus, I r is
ventr icosa, L eibnitz ia anandr ia and so on.
1. 3　Quadrat establishment
The sample plot w as chosen on the typical
sect ion that hav ing bet ter pro tective measures,
ident ical composit ion o f plant species, st ructure of
community and habitat condit ions. It s ar ea w as 100
m×100 m . Subject iv e sampling in the experiment
w as adopted and aimmed to increase our accuracy
of determ inat ion
[ 6] , that w as the quadrat r andomly
arranged.
1. 4　Mowing stress treatment
The exper iment set up four lev els of mow ing
st ress t reatment alto gether. First ly, by mow ing
only once a year , the mow ing t ime w as ar ranged as
in the follow ing, they are: M ay 20, June 5, June 20,
July 5, July 20, Aug . 5, Aug . 20, Sep. 5 & Sep. 20,
nine levels alto gether. By mow ing str ess tw ice a
year, the f iv e t reatment levels w hich mow ing
interval w as tw o months, were arranged as in the
follow ing : May 20 + July 20, June 5+ Aug . 5, Jun
20+ Aug. 20, July 5+ Sep. 5, July 20+ Sep. 20, and
four tr eatment lev els w hich mow ing interv als were
tw o and a half months: May 20+ Aug . 5, June 5+
Aug . 20, June 20+ Sep. 5 & July 5 + Sep. 20. By
mow ing stress three times a year plus mow ing
interv al at one and a half months, the three levels
w ere arranged: May 20+ July 5+ Aug . 20, June 5+
July 20+ Sep. 5 and June 20+ Aug . 5+ Sep. 20.
1. 5　Determined contents
U nder mowing st ress, the feedback response
show ing quantitat iv e char acter ist ics was height ( or
length) , cover-deg ree, density of the edificato plant
species, main dominant species and their
community range w as determ ined. Also, the
abovegr ound biomass and cr ude protein content of
community w ere determined. T he quadrat w as 1m
×1m . T he determ inat ion w as repeated 6 times.
1. 6　Methods
In the quadrat fo r determ ining height ( or
length ) of each populat ion, it s average height
( or length) of high( or long) plants, median-high( or
long ) plants, and low ( or sho rt ) plants w as assumed
as the plant height ( or leng th) of the populat ion in
determinat ion. T he determ inat ion of cover-degr ee
populat ion and community w as car ried out by using
r ope pulled as a small check in tr ial . The quadrat
count w as also used as for density determinat ion.
In addit ion, due to the inconveniency to determine
the r egenerativ e density and cover -degree range of
F . chelungk iangnica and C. squar rosa, the tw o
species of herbage plants w er e combined into one,
and named as clustered grass. Sampling accor ding
to harv est method w as used to determine herbage
y ield
[ 5]
. T he g rass sample mow ed was put into
plast ic bag at once, then covered w ith special cloth
bag , carried into labo rato ry f inally . The sample w as
w eighed fresh weight at once, then put into cloth
bag to dry in the shade, to constant w eight , dr y
w eight w as w eighed. Crude pr otein content of the
27第 1期 多立安等:生长季羊草割草场刈割胁迫响应
first and the second crop w as determined by
kjeldahl method, then converted to cr ude pro tein
yield per ar ea.
2　Results and analyses
2. 1 　 The chief quantitative characteristics of
population and community in relation to natural
seasonal dynamics
The chief quant itat ive characterist ics in
gr ow ing season of natural seasonal dynam ics of
populat ion and comunity w as indicated in Table 1.
The growing height of L . chinensis and the
st retching length of P . f lagel lari s all reached
maximum status on July 20 or so , w hich w er e 44.
5cm and 10. 4cm respect iv ely . T he covering-degr ee
o f L . chinensis population reached the max imum
30. 8% on Aug. 5 or so. T he max imum of P . f lagellar is
and community covering-deg ree appeared on July 20,
r eaching 7. 0% and 72. 3% respect ively , and the g rass
clust ering on July 5, i. e. 8. 2% . The density of L . chinensis
population and community a ll reached t he m aximum 250
plants/ m
2
and 1313 plants/ m
2
on Aug . 5. Density of
clust ered g rass and P . f lag ellar is at tained the highest on
M ay 20, and then decreased g r adually r ather so on
af terw ards.
Table 1　The chief quantitative characteristics of population and community in relation to natural seasonal dynamics by
mowing once at an interval half a month ( cm, % , plants or clusters/m2, g/m2)
Populat ion
and
community
Content
determined
Interval of m ow ing dates
M ay 20 Ju ne 5 Jun e 20 July 5 July 20 Aug . 5 Aug. 20 Sep. 5 Sep. 20
L . chinensis Heigh t 14. 9 20. 2 34. 7 39. 3 44. 5 41. 5 40. 7 38. 0 32. 8
Cover-degree 7. 7 9. 5 11. 5 19. 7 30. 5 30. 8 30. 0 27. 2 24. 2
Density 166 170 184 218 222 256 250 232 225
Clustered Cover-degree 3. 7 4. 2 7. 0 8. 2 5. 8 5. 2 4. 7 3. 5 1. 8
grass Density 112 101 81 70 54 46 39 26 14
P . f lag el lari s Len gth 3. 3 5. 3 8. 9 9. 0 10. 4 9. 2 7. 3 5. 7 4. 5
Cover-degree 2. 6 5. 0 5. 2 5. 8 7. 0 6. 3 4. 0 3. 3 2. 8
Density 141 132 126 120 98 79 71 67 58
Comm unity Cover-degree 23. 0 32. 8 40. 8 53. 5 72. 3 69. 2 66. 7 64. 0 46. 2
Density 909 938 1101 1199 1288 1313 1196 1005 933
Yield of f resh grass 16. 8 74. 2 196. 0 307. 4 404. 2 451. 7 416. 6 345. 3 271. 3
Yield of dr y mat ter 9. 6 27. 7 65. 3 115. 6 165. 0 193. 3 180. 8 173. 2 147. 3
Crude pr otein conten t 1. 3 3. 5 7. 6 12. 0 15. 5 16. 4 13. 7 11. 9 8. 6
Herbage yield was low at f irst , and the grass dry
yield w as only 9. 6 g / m
2
on M ay 20, as both w ater
and heat condit ions w ere improved, it reached the
max imum 197. 3 g/ m
2
on Aug. 5. In the init ial
period of g row th, crude pr otein yield DM was
relativ ely low , as the increase o f biomass, reaching
the max imum 16. 4 g / m
2
on Aug . 5 and later on
w ith the com ing of autumn, it decreased. The
accumulated dynamics of protein y ield ( Pr ) w as
clo sely related to the dynamics status of herbage
yield ( Y ) as show ing somew ha t a st riking str aight line,
w ith P r = 1. 6925 + 0. 096Y and R = 0. 9302
* *
, finally it
reflected on such a scene that the accum ulated peak of
pro tein wa s in parallel consistently with t he peak o f herbage
yield more or less.
2. 2　Mowing twice at an interval of two months
In the second crop ( Table 2) , f rom the f irst
t reatment ( M ay 20+ July 20) to the last ( July 20+
Sep. 20 ) , the r eg enerativ e height o f L . chinensis
populat ion hast ly dropped from 30. 8cm to
16. 3cm, w ith arange of 47. 1%, and regener at ive
cover-deg ree, from 17. 5% to 0. 4%, dropping 97.
3% and meant imely the regenerat ive density also
dropped fr om 152 plants/ m
2
to 3 plants/ m
2. On the
w hole, the later w as a second mow ing t reatment ,
the larger one, w as then then show ing a dropping
r ange of regenerat ive g row ing potent ial o f L .
chinensis populat ion. It w as indicated that L .
chinensis is not so g ood as to endure mow ing in the
28 草　地　学　报 第 9卷
later stage. In the second treatment f rom the
bot tom date( July 5+ Sep. 5) , the g row ing potent ial
st rength of these tw o species of clustered gr asses
and P . f lagellaris was show ing st ronger t rend than
those in the other tr eatments int rial , the
r eg enerative density of clustered g rass w as 60. 3%
Table 2　The stress eff ect on main quantity characteristics of population and community by mowing
twice at interval of two months( cm , % , plants or clusters/ m2, g/m2)
Populat ion
and
community
Conten t
determined
Mow ing d ate
M ay 20+ July 20 June 5+ Aug. 5 June 20+ Aug . 20 July 5+ S ep. 5 July 20+ Sep. 20
L . ch inensis Heigh t 13. 3+ 30. 8 19. 8+ 29. 2 27. 8+ 24. 5 39. 3+ 24. 2 44. 5+ 16. 3
Cover-degree 7. 0+ 17. 5 9. 0+ 16. 2 12. 2+ 8. 3 19. 7+ 5. 0 30. 5+ 0. 4
Density 166+ 152 171+ 130 177+ 96 218+ 56 221+ 3
Clustered Cover-degree 3. 7+ 6. 3 4. 7+ 9. 3 7. 2+ 9. 2 8. 2+ 10. 0 5. 8+ 1. 5
grass Density 112+ 50 104+ 104 80+ 92 70+ 126 56+ 8
P . f lag el lari s Len gth 3. 0+ 5. 5 4. 4+ 6. 5 8. 3+ 5. 7 9. 0+ 4. 2 10. 4+ 3. 4
Cover-degree 2. 2+ 3. 3 4. 3+ 2. 8 4. 8+ 7. 7 5. 8+ 7. 7 7. 0+ 3. 3
Density 142+ 66 126+ 120 122+ 7 120+ 127 71+ 83
Comm unity Cover-degree 24. 3+ 50. 0 32. 3+ 52. 5 37. 2+ 45. 5 53. 5+ 47. 0 72. 3+ 19. 5
Density 962+ 1347 1066+ 1169 1056+ 1166 1213+ 1010 1228+ 614
Yield of f resh grass 24. 8+ 259. 5 64. 9+ 277. 0 188. 2+ 291. 0 301. 3+ 276. 8 404. 2+ 98. 1
Yield of d ry mat ter 12. 8+ 91. 9 26. 6+ 104. 9 68. 8+ 104. 4 116. 3+ 96. 5 165. 0+ 41. 2
Crude p rotein conten t 1. 8+ 12. 5 3. 3+ 12. 3 8. 0+ 10. 7 12. 0+ 9. 0 15. 0+ 3. 4
higher than that in the first tr eatment , 93. 7%
higher than that in the last , and that of P.
f lagellaris was 48. 0% higher than the f irst and
34. 7% higher than the last . T his show ed that they
w er e st ronger than L . chinensis populat ion in
standing mow ing t reatment . Fr om the total density
of community obser vation, the later w as the t ime of
the second mow ing , and the larg er w as the
dr opping range of it s density. On approval o f both
herbage and crude pro tein yielding records, in the
fo rmer, in tw o t reatments ( M ay 20 + July 20) and
( June 5 + Aug. 5 ) , because of the first mow ing
t reatment w as under to o early, during tw o months
after the t reated herbage plants turned fr esh-
gr een, the y ield of the first crop grow ing situat ion
and its pr otein content w as relat ively low , and
mor eover , w ater , heat and o ther condit ions w ere
not show ing good and ideal in initial stage, and the
herbage grow ing situat ion w as not actually
changing on into peak period, the total herbage and
cr ude protein y ielding status w ere too clearly low er
than those o f the later three t reatments, among
which the yield and crude pro tein y ield o f the first
and second crop on trial ( July 5 + Sep. 5) w ere
r ecorded tow ar ds the highest , they w ere 212. 9g/ m
2
and 21. 0 g / m
2
respect ively. So that this pat tern of
mow ing str ess condit ion only show ed that af ter the
f irst cr op developed fully , then the second mow ing
w as carried out so as to be sustained to obtain both
r elat ively high herbage and crude pro tein yields at
both the same high stage.
2. 3　Mowing twice at an interval of extending to
two and a half months
In the second crop ( T able 3) , the reg ener at ive
height of L . chinensi s populat ion in the second
treatment ( June 5+ Aug . 20) w as g row ing into the
highest stage, w hich was 31. 5cm, being 7. 8cm
higher than that of the lat ter t reatment ( July 5 +
Sep. 20 ) . It show ed that the variable range of
r eg enerative height w as somewhat lower than that
the t reated plant inter val in tw o months. Fr om the
f irst to the fourth t reatments, the reg ener at ive
cover-deg ree of plants tended to dr op by decreasing
97. 4%. Regenerat iv e density of the second
treatment was the highest , 212 plants/ m
2, 34. 4%
higher than that o f the f irst t reatment , and also 97.
2% higher than that of the fourth. From study on
29第 1期 多立安等:生长季羊草割草场刈割胁迫响应
Table 3　The stress ef fect on main quantitative characteristics of population and community by
mowing twice at an interval of two and a half months ( cm, % , plants or clusters/m2, g/m2)
Populat ion
and
community
Conten t
determined
Mow ing d ate
M ay 20+ Aug. 5 June 5+ Aug. 20 June 20+ S ep. 5 July 5+ Sep. 20
L . ch inensis Heigh t 14. 9+ 29. 8 20. 2+ 31. 5 34. 7+ 27. 3 39. 3+ 23. 7
Cover-degree 7. 6+ 19. 2 9. 5+ 16. 7 11. 5+ 4. 5 19. 5+ 0. 5
Density 166+ 139 170+ 212 184+ 60 218+ 6
Clustered Cover-degree 3. 6+ 7. 0 4. 2+ 4. 5 5. 0+ 2. 2 8. 2+ 7. 8
grass Density 120+ 54 101+ 46 81+ 29 70+ 48
P . f lag el ler is Len gth 3. 3+ 7. 3 5. 3+ 5. 2 8. 0+ 5. 2 9. 0+ 4. 3
Cover-degree 2. 6+ 8. 5 5. 0+ 10. 0 5. 2+ 5. 5 5. 8+ 5. 2
Density 141+ 124 132+ 138 126+ 133 120+ 103
Comm unity Cover-degree 23. 0+ 63. 8 32. 8+ 60. 0 40. 8+ 44. 3 53. 5+ 30. 6
Density 909+ 901 938+ 1221 1101+ 1957 1199+ 672
Yield of f resh grass 16. 9+ 390. 0 74. 1+ 383. 3 196. 0+ 285. 5 301. 6+ 196. 0
Yield of d ry mat ter 9. 7+ 158. 3 27. 7+ 147. 1 65. 3+ 111. 9 115. 9+ 86. 9
Crude p rotein conten t 1. 3+ 20. 0 3. 5+ 16. 0 7. 6+ 10. 5 12. 0+ 7. 3
the regenerat ive density , only the second mow ing
in the second treatment promoted the regenerat ive
increasing density of L . chinensis populat ion but the
other t reatments hereby inhibited it . In
regenerat ive herbage plants, the value of
quant itat ive characterist ics of clustered gr asses
fr om the f irst to the third t reatment most showed
dr opping t rends, but that o f the fourth only
appear ed to rise. It also showed that clustered
gr asses had r elat ively str ong ability o f standing
mow ing at later stage. T he dif ference of
regenerated quant itativ e char acterist ic value of P.
f lagellaris among each and every t reatment w as
not very big, but show ing that P . f lagel lar is in
it self had some good adaptat ive react ion to this
so rt of mow ing pat tern. Regenerat ive density of the
second treatment comunity w as somewhat higher
than that in the o ther t reatments. In the daily
t reatment ( July 5 + Sep. 20 ) , the highest to tal
herbage yield 202. 8 g / m
2
was obtained, being much
higher than that of other three t reatments. The
reason fo r obtaining low er total her bage yield w as
that the f ir st crop didn t have developed fully
before the second mow ing st ress. In t reatment
( M ay 20+ A ug . 5) , the cr ude pro tein content being
the highest , was 21. 3 g / m2 . T his resul t w as no t
consistent w ith the case o f her bage total yield,
indicat ing that the posit ive effect of this mow ing
pat tern on plant community w as not bet ter than
that of mow ing effect at an inter val o f tw o months
more o r less.
2. 4　Mowing three times at an interval of one and
a half months
　 　 Mow ing three t imes had w eakened the
g row ing potent ial of L . chinensi s population much
more than mow ing tw ice( see table 4. ) With regar d
to the regenerat ive density , as w henever the time of
mow ing w ent on, the more the t imes of mow ing ,
the big ger the r ange of density decreasing . Under
the similar cases, as to the clustered gr asses and P .
f lag ellaris, the third mow ing had indicated a
decreased g row ing potent ial mor e heav ily than the
second mow ing , but the droping range of g row ing
potent ial in the third mow ing w as not br oader than
that of L . chinensis populat ion. This show ed that
they had somewhat st ronger ability of standing
mow ing than that of L . chinensis. From the
community yieldage r ecords, the total herbage
y ields in three t reatments w ere all ver y low , ev en
much low er than that of the tr eatments o f mow ing
once a year w henever ther e had the highest
biomass recor d ( Aug. 5 ) . In addit ion, the total
crude protein contents of mow ing thr ee t imes w er e
low er than tho se o f mow ing tw ice. In the same
case, by mow ing three t imes a year, ow ing to the
30 草　地　学　报 第 9卷
fact that the t ime interval was sho rt and each crop
gr ow ing st reng th didnt develop ful ly at each time,
the to tal protein content w as af fected to some
ex tent . T herefo re, the negative st ress effect o f this
mow ing pattern on our gr assland study w as the
bigg est .
Table 4　The stress ef fect on main quantitative characteristics of population and community by
mowing three times at an interval of one and a half months ( cm , % , plants or clusters/m2, g/m2)
Populat ion
and
commun ity
Conten t
determined
Mow ing d ate
May 20+ July 5+ Aug. 20 June 5+ July 20+ Sep . 5 Ju ne 20+ Aug. 5+ Sep. 20
L . chinensis Height 12. 2+ 24. 0+ 16. 6 18. 4+ 28. 0+ 19. 3 27. 2+ 18. 3+ 8. 6
Cover -degree 7. 0+ 7. 5+ 0. 9 9. 2+ 11. 3+ 0. 9 12. 3+ 6. 5+ 0. 4
Dens ity 161+ 151+ 10 174+ 127+ 13 184+ 89+ 5
C lus tered Cover -degree 3. 7+ 2. 5+ 14. 7 4. 7+ 6. 6+ 5. 5 7. 8+ 7. 3+ 5. 5
g ras s Dens ity 117+ 49+ 58 108+ 91+ 100 81+ 104+ 112
P . f lagel lar is Length 2. 4+ 3. 6+ 4. 8 5. 0+ 4. 8+ 2. 8 8. 0+ 4. 2+ 2. 1
Cover -degree 2. 0+ 3. 8+ 7. 0 4. 2+ 5. 2+ 4. 2 5. 0+ 3. 5+ 2. 5
Dens ity 138+ 79+ 75 133+ 87+ 109 124+ 80+ 64
C ommunity Cover -degree 23. 0+ 35. 3+ 39. 2 29. 8+ 43. 5+ 26. 7 39. 2+ 33. 0+ 15. 3
Dens ity 897+ 1044+ 881 955+ 1103+ 1038 1070+ 1130+ 703
Yield of fr esh grass 20. 7+ 193. 7+ 202. 5 54. 6+ 238. 2+ 115. 0 165. 3+ 180. 0+ 46. 3
Yield of dry m at ter 10. 5+ 62. 3+ 63. 9 26. 2+ 78. 5+ 42. 1 61. 5+ 57. 5+ 18. 3
Cru de protein content 1. 4+ 8. 6+ 8. 5 3. 3+ 10. 0+ 5. 0 7. 1+ 6. 4+ 2. 2
3　Discussion
3. 1　 From the determ ined results of the main
quant itat ive characterist ic dynam ics study in
gr ow ing season, though at the same interval of
t ime, the variable range of quant itat ive
characterist ics of each plant population and
community w as somewhat dif ferent , their laws of
variance w er e indicat ing all the same “one peak”
type. But the peaks alw ays appeared at dif ferent
t imes, show ing that the rhythm of each populat ion
development w as not the same. From observing the
variable laws o f peak appearances, in the early
stage of herbage gr ow th, because of the small leaf
area appear ance and not ideal w ater supply,
including heat condit ions, the photosynthesis in
appear ance w as slow and the org anic mat ter
accumulat ion w as also small and slow . That
show ed that the her bage quant itat ive
characterist ics of populat ion volume, cover -degree
variat ion and so on increasing slow ly at the
beg inning . But along w ith the g row th of herbage
plants, the improvement of w ater supply , including
heat conditions, photosynthesis w ould be becoming
fast , and also it s accumulation increasing, the
char acter ist ic v alues of populat ion volume and its
cover-deg ree also r eaching the peak value quite
fast ly . Af ter that , as the her bage plants became
entering into reproduct ive g row th f rom nutr it ive
status and then w ater supply and heat conduct ive
condit ions became wo rse, plant population
g radually appro ached to gr ow ing stop stage.
Besides, w henever af fected by some natural forces
( fo r ex ample, the w ind, some animal ef fects and so
on) , w ithering was increasing , it w ould be show ed
that the quant itat ive character ist ics o f plant
populat ion height , cover-deg ree and etc. were
tending to drop af ter st riding the peak. Except that
the density variation of L . chinensi s populat ion w as
slight , the density variance range o f some clustered
g rasses and P . f lagel lar is populat ion w as relat ively
big. The big gest and the smallest density o f their
populat ion w ere show ing dif ference to eight and
tw o t imes respect ively. T his indicated that as
entering at the stag e o f exuberant grow th, ow ing to
31第 1期 多立安等:生长季羊草割草场刈割胁迫响应
the fact that the super io r status of L . chinensis
populat ion in the community w as increased, the
status of some clustered gr asses and P . f lagel lar is
populat ion in the community droped, this point
could be shown by the rat io of DM y ield of L .
chinensis among DM yield of the community ( Table
5) . From the f irst reco rd determinat ion date ( May
20) to Aug. 20, the rat io w ould g radually increase
fr om 36. 5% to 58. 7% , only show ing a slight ly
dr opping at the later stage. The exuberant g row th
and development of the edif icato L . chinensi s,
together w ith it s superior status in the community
play ed a leading r ole, w hich w as an important sign
on the grassland in good development state. At
g row ing season, the herbage and crude protein
y ields of grasses w ould show their variat ion as a
“one peak”pat tern, and r eaching the peak value
around Aug. 5, w hich w ere 197. 3 g/ m
2
and 16. 4 g /
m
2
respect iv ely . Further analy ses indicated that the
variance law of both herbage and crude protein
y ields w ere similar, and their common relat ing
coeff icient was 0. 9302* * . Observ ing among all the
r elat ing coeff icients of L . chinensis population
densit ies and to tal her bage yields, only L . chinensis
populat ion was then showing in a posit ive relation
( 0. 9646
* *
) , the cluster ed grasses and P .
f lag ellaris were indicat ing in a negat ive relation( -
0. 8825* * , -0. 8749* * ) .
Table 5　Dynamics concerning the percentage of L. chinensis and mesophytic
herbal plant yields in total of community( % )
Content
Mow ing date
May 20 June 5 June 20 July 5 July 20 Aug . 5 Aug. 20 Sep. 5 Sep. 20
L . ch inensis 36. 5 48. 7 38. 6 37. 4 43. 0 42. 9 58. 7 55. 4 55. 1
Mesophyt ic h erbs 63. 5 51. 3 61. 4 62. 6 57. 0 57. 1 41. 3 44. 6 44. 9
3. 2　T o make reasonable ut ility o f g rasslands is to
utilize them scient ifically, that is, not to make the
gr assland degenerate and ought to make herbage
resources r eaching good and permanent
regenerat ivity in both sides. T o make the
pr oduct ive potent ialit ies is to obtain both high-
yield and high-quality her bage in good w ay , that
may be considering f rom also tw o hands of
quant ity and quality. The quantity is most ly
demonstr ated by herbage y ield and the quality is ,
of cour se most ly by pr otein content
[ 5] . Therefor e,
to bring the most product ive potent ialit ies of
gr assland into play needs us to consider using all
the regenerat ive grasses spp. of grasslands and to
inquire into their productive char acter ist ic indexes
of g rassland regener at ivity, nut ritive state,
pr oduct ive st ructure and so on . In v iew o f this
situat ion, combining the t radit ional mow ing system
in the locality w here mow ing and utilizing ar e once
carr ied out fo r a y ear , it s average mow ing t ime is
Sep. 10, and mean height is used to left 10cm , w e
ought to discuss the problems so as to w hether the
g rassland resources w ere ut ilized t ruly and
r easonably or not , or whether the product ive
potent ialities of lo cal grasslands w ere brought into
play t ruthfully or no t , and so on. Analysed from
the regenerat ivity o f grasslands, high herbage
y ields and protein contents could be obtained by
mow ing tw ice, but if the second cr op w as ut ilized
too early, the her bage y ield w ould w ould be
low ered mo re or less. Herbage yield and protein
contant could not be obtained to the most extent by
mow ing once or three t imes, especially mow ing
three t imes alw ays m ight af fect the L . chinensis
density would be dropped 14 t imes, on average. In
the two mow ing and ut ilizing , tr eatments of using
the first crop too late it could make L . chinensis
density dr op distinct ly . So in this case, the effect
on L . chinensis populat ion should not only be
considered, but also w henever to obtain high
herbage yield and quality, it also should be taken
account of . Analysed f rom the product ive str ucture
o f grasslands, the dynamical changing var iat ion of
0～10cm layer f rom July 5 to Aug . 19, they are
32 草　地　学　报 第 9卷
44. 7% , 27. 2% , 31. 4% and 28. 9% of the to tal
yield, during the period, the average yield of
0～10cm layer w as accounting for 33. 0% o f the
total y ield. If only calculated by mowing once a
year, it w ould show clear ly that the system of local
mow ing and ut ilizing w as not r easonable in
pr inciple. T he reason w as also clear that if
calculated by reasonable mow ing height in 5～6
cm [ 5] , the yielding w aste as a resul t of too high
cr op lef t by mow ing made up about 15. 0% o f the
total harvest yideld; because o f the mowing season
too late, the y ielding w aste w ould make up to 16.
0% o f the total har vest yield. The w asted herbage
yield at least thus made up to 30. 0% o f the to tal
yield by adding them. In addit ion, ow ing to mow ing
season being to o late, the protein content of
herbage w ould be decreased and in turn this made
pr otein content by dropping 20. 0% , show ing at
last that the productive potent ialit ies of local
gr assland r esources had not been brought into fully
play .
3. 3　According to the above analyses, mow ing too
many times w ould affect the herbage populat ion
and community great ly. As a w ho le, w henever the
mow ing intensity increased, the dropping range of
herbage grow ing potent ial o f the gr assland
increased immediately . T he later the date of the
second mow ing t reatment , the clearer the dropping
t rend of the grow ing potent ial , part icular ly the L .
chinensis populat ion then dropped most ly,
becoming much larger than the clustered grasses.
This indicated that the L . chinensis populat ion w as
the w orst to stand against mow ing . Besides, thet
the L . chinensis possessing luxuriant grow ing
tendency is a sign of go od developing state. All the
clustered grasses w ere the dominant species g row n
on the clustered grass grassland, but P . f lagellaris
is usually the indicated plant of degenerated L .
chinensis grasslands. M oreover, in view of the effect
o f mowing str ess, if t reated unr easonably on trial,
and along w ith management measure laying of f , the
g rassland w ould be liable to be dest roy ed. T he
protein contents o f g rassland w ould be affected
g reatly under different t reatments of mow ing ,
among fr om which, if mow ing tw ice could obtain
r elat ively high pr otein content , then mow ing once
o r three t imes come secondly. T he first and the
second crop had attained relat ively high protein
contents on using our g rassland to o late, bo th of
them would make low er herbage quality, mow ing
and utilizing tw ice a year, that is the July 5+ Sep. 5
t reatment being somewhat ideal, but at the same
t ime, the grassland should be lain fallow and
mow ed in turn, how ever , if the g rassland w as
mow ed and ut ilized once a year , the opt imum
mow ing t ime w ould be in time during the end of
July and Aug . 2
Ref erences
1　M eng Rong. The studies on can op y regrow th vigor of des ert
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1988, ( 3) : 1～5
2　Chen Guangyao. Ef fects of cut t ing regimes on dry mat ter yield
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50～52
3　Zh ong Yankai, Bao Qin ghai , Su n Wei. A s tu dy on reasonable
m owin g s ystem of n atural m ow ing stepp e rangeland in Baiyinxile
Farm, in ner Mongolia [ J ] . AC TA E cological , 1991, 11 ( 3 ) :
242～249
4　Duo Lian . Improve nu tr itive s itu at ions of grass lan d on providing
n it rogen an d promot ing an imal protein conten t p roduct ion [ J ] .
H eilongj iang animal science and technology , 1990, ( 2) : 52～54
5　 Nei Monggolian Agricul tural College Grasslan d Management
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33第 1期 多立安等:生长季羊草割草场刈割胁迫响应