Lam hpc
/ N G H I E N c u t ; ANH HU^OfNG THAM THlTC VAT TANG THAP DEN CU'OfNG DQ XOI MON Dl/OfI MOT SO TRANG THAI RlTNG
6 KHU BAO TON THIEN NHIEN THl/ONG TIEN - HOA BINH
Pham Thi Kim Chi, Bui Hung Trinh, Nguyin Van Tuy§n 7715. Trudng Dgi hgc Ldm nghiep
T O M T A T
N ^ i e n cuu thu ducrc mot so ket qua phan anh moi tuong quan Uong anh huong cua tham thuc vat t§ng thip den cuong do xoi mon dudi mot so trang thai rimg a rimg 6 KBTTN Thuong tien - Hoa Binh: (1) Anh hucmg ciia chieu cao lop cay bui din luong xoi mon duoi rung the hi0n qua phuong trinh tuyen tinh mpt lop dSng biin voi miic lien he tuong doi chat: Y= -23,5 + 84,99*X voi R=0,74; (2) Anh huong cua duong kinh tan lop cay byi den lugng xoi mon dudi rimg the hien qua phuong trinh tuyen tinh mpt lap dong bien vdi muc liSn h^
tuang d6i chat: Y=26,7 + 43,83*X vdi R= 0,54; (3) Anh hudng ciia dg che phu tham tuoi, cay bui dSn lugmg xdi mon dudi rimg the hi^n qua phuong trinh tuyen tinh mpt lap nghich bien: Y=129,37 - 0,836*X vdi R=0,66;(4) Anh hudng cua lop tham kho den lugng xoi mon dudi rimg the hi^n qua phuong trinh tuyin ti'nh mgt lop nghich bien: Y=I82,6-1,718*X; (5) Anh hudng ciia chi tieu long hpp phan anh cSu tnic ciia lap thuc v|t tang thap den lupng x6i mon dudi rimg.
Tir khoa: KBTTN Thirgng Tien, thac vgt tang thap, trgng thdi rimg, xdi mon dat
I. DAT VAN BE
Xdi mdn dang la van dt het sue nghiem trong, Phdng ehdng xdi mdn duoc xem la nhiem vu khd khan eho cac nha hoach dinh chinh sach, quy hoach va su dung ngudn tai nguyen dat dai. Tac dgng xdi mdn khdng chi anh hudng true tiep tdi cac hoat dpng san xuSt ndng lam nghiep tai eho ma cdn anh hudng den mdi trudng sinh thai. Xdi mdn dSn den d§t bi thodi hoa nhanh ehdng ve moi phuang dien nhu: hoa hpc, ly hpc va sinh hpc. Day la nguyen nhan co ban lam giam dp phi cua dSt va tfnh ben vimg cua viec sir dung d^t. Xdi mdn dat chiu cinh hudng ciia nhi^u yi\x td tu nhien nhu: mua, dat, nude, dia hinh, Idp phu thuc vat,...va tfnh chu quan ciia con ngudi trong cac hogt dpng canh tac. Vi vay, nghien cuu ve xdi mdn eung nhu hiSu dupe mdi quan he giua xdi mdn va cac nhan td lien quan den xdi mdn la mdt ddi hoi mang tfnh thdi su.
Xu3t phat tir co sd dd vdi muc tieu, gdp phan lam co sd khoa hpc va thuc tiln trong nhung nghien cuu ve xoi mdn chung tdi tien hanh thuc hien da tai: "Nghien cim dnh hu&ng
thdm thuc vat tdng thdp din cuong do xoi mon diroi mgt so trgng thdi rimg o KBTTN Thuong tien - Hoa Binh ".
U. VAT LIEU, PHlTONG PHAP NGHIEN CUtJ 2.1. Vat lieu nghien cuu
+ Nghien cuu dac diem cau tnic eac trang thai rung tai KBTTN Thuong Ti6n
+ Nghien cuu dac diem xdi mdn dudi cac trang thai rung tai KBTTN Thuong Tih
+ Nghien cuu anh hudng ciia tham thuc vat tang thap den cudng dp xdi mdn dudi cac ti^g thai rung tai KBTTN Thupng TiSn
2.2. Phumig phap nghien ciru 2.2.1. Phirong phdp ngoai nghiep Xdy dimg cdc mo hinh quan trdc lirgng xoi mon diroi rdng
Md hinh quan trac lupng dit xdi mdn dudi rung duac xay dung la md hinh mang chSn cai tien, mang chan dupe xay dung taii cac diem tu thuy tu nhien cua cac bai do duoc xac dinh dudi cac trang thai rirng khac nhau cua KBTTN Thuong Ti6n.
Bai thu nude nai dat cac mang chan cai tien dupe lira chpn va thiSt kg vdi dien tfch tir 10
1 0 0 - 3 0 0 m l
TAP c m KHOA H Q C VA CONG NGHE LAM N G H I E P SO 1-2015
Tai khu virc nghien ciru xay dung 24 md hinh quan trie lupng xdi mdn d 6 trang thai rimg dae trung cua KBTTN Thupng Tidn:
rimg trung binh, rimg ngheo, rimg phuc hdi, rirng tre nua, rimg trdng, dat trdng.
Tien hanh thu thap va quan trie sd lieu trong sudt miia mua nam 2012. Tai mdi md hinh tien hanh thu thap sd heu nhu sau:
1. Sd Ueu ve lupng mua duoc do bing cac vu ke dat d cae vi tri thich faprp g i n khu vuc xay dvmg md hinh nghien cim.
2. Sd lieu Idp dat meit cua md hinh: Tai eac md hinh de tai tien hanh liy m i u dat ting mat tai 5 vi tri khac nhau phan bd d8u trong dien tich cac md hinh.
3. Sd lieu xdi mdn: sd lieu ve xdi mdn dupe thu thap sau mdi tran mua, sau khi mua chd cho lupfng dat xdi mdn lang xudng tien hanh thu thap m i u nude va dat tai mdi bai thu.
Lupng nude dupe xac dinh bing xd cd khic vach sau dd lay ve 500ml nude d^ phan tfch lupng xdi mdn cd trong nude. Lupng dat dupe can true tiep tai bai thu sau dd lay mau ve phdng thi nghiem phan tich xac dinh dp am cua cac mau.
4. Sd lieu tham thuc vat: dugc di6u tra true tiep tren cac mo liinh quan trac lupng xdi mdn dudi rimg cho timg trang thai rung nghien cuu.
Cac chi tieu cau tnic dupe dieu tra bao gdm: dp tan che, che phu tham tuoi, che phu tham khd, chieu cao viit ngpn (Hvn), chieu cao dudi canh (Hdc), dudng kinh tan (Dt), cay bui, tham tuoi, tham khd.
+ Dp tan che, che phii tham tuoi, che phu tham khd dupe dieu tra thdng qua he thdng cac diem each deu 1 m trong toan bd dien tfch ciia md hinh nghien cuu bang may do dp tan che.
+ Dac diem tang cay cao: dudng kinh 1.3m (D1.3) dupe xac djnh bang thudc do thude day vdi dp chinh xac den dm; dupe xac dinh bang thudc do thudc day vdi dp chinh xac den dm;
Ldm hgc
chieu cao vut ngpn (Hvn), chieu cao dudi canh (Hdc), dudng kinh tan (Dt) dupe xac dinh bang sao vdi dp chinh xac den cm
+ Dae diem ting cay bui dupe xac dinh cho timg md hinh trong toan bp dien tfch md hinh qua cac chi tieu: loai cay, chieu cao (Hcb), dudng kinh tan (Dtcb), dp che phu (CPcb), tinh hinh sinh trudng (tdt hay xau).
+ Dac diem lap tham tuoi dupe xac dinh cho tiing md hinh trong toan bd dien tfch md hinh qua eac ehi tieu: loai cay, chieu cao (Htt), dp ehe phii (CPtt), tinh hinh sinh trudng (tdt hay xau).
+ Dac diem khdi lupng tham khd, tham tuai dupe xac dinh qua khdi lupng tham khd, tham tuoi trong 15 d dang ban cd kich thudc 1 m^ phan bd deu trong cac md hinh nghien ciiu.
2.2.2. Phiromg phdp xir ly npi nghiep Trong qua trinh xu ly sd lieu va phan tich sir lien he, vai trd cua tham thuc vat ting thip den cudng dp xdi mdn dudi rimg de tai se ung dung cac phan mem thdng ke: Exeell, SPSS dd phuc vu nghien ciiu. Cu the nhu sau:
1. Xac dinh dp am cua dat bang phuong phap can say d nhiet dp lOS^C.
M1-M2, W%--
MOOMl
Trong dd:
W%: dp i m tuong ddi (%);
M1: trpng lugng cua dat tuoi (gam);
M2: trpng lugng cua dat khd kiet (gam).
2. Xac dinh ty trpng (d) bang phuong phap picndmet (binh ty trpng)
M2 ^ Ml Pn ~ M2^P\-P2 Trong dd:
d: ty trpng ciia dat (g/cm^);
Pn: khdi lugng cua the tich nude bi d i t chiem chd trong binh (g);
PI: khoi lupng cua binh va nude (g);
P2: khoi lugng binh chira nude va dit (g);
M2; khdi lugng dat khd kiet (g).
d^-
TAP CHl KHOA HOC VA CONG NGHE LAM NGHIEP SO 1-2015 11
Lam hpc
Dp x6p tinh theo cong thiic: UI. KET QUA NGHIEN CUU VA THAO LUAN X%= ' ^ ~ ^ * 1 0 0 ^ - l - ^'^ * ' ^ " ' '^^ 'TO' <^c t r a n g thai rirng
d tai KBTTN Thirgng Tien Trong do: 3.1.1. Bdc diem cau trdc tdng cdy cao
X: do xop cua dat (%); Xren c a so tong hop s6 heu tii cac 6 tieu d: ty trong cua dat (g/cm') ^ (,|,^ j „ y , ^ ^ j p , ^ jj^jj , ^ i ^ g ^ . ^^^^^ i^j^j^
D: dung trong cua dat (g/cm' ^^^ ^ ^ „ g ^^^^• ^ ^ ^ „ ^ ^ ^ j ^ j ^ ^ . Bang 4.1. Sac i S ^ / ^ g cdy cao dudi cdc irang thdi rdng n^ien cuu tgi KBTTN
Thuong Tten- Hda Binh Trang
thai Tan c)ie
N/lia D1.3 (cm)
Trung binh Hvn Hdc (ra) (m)
Dt (m)
H? so bien dgng (S%) D1.3 Hvn Hdc Dt (cm) (m) (m) (m) 0,46 971 17,1 8,6 5,4 4,1 56,0 47,5 51,4 46,1 Rimg
ngheo Rimg
phuc 0,47 1087 14,1 6,7 3,4 3,3 49,6 53,1 50,4 53,9 hoi
Rirng trong Tre nijra Rimg
TB
0,53 1967 7,2 4,7 2,4 1,7 12,7 19,6 27,2 17,7 0,50 3106 6,7 12,1 4,4 1,6 18,4 12,3 19,5 24,0 0,51 841 20,6 12,0 6,5 5,1 57,5 34,9 37,3 38,9
Buong kinh cdy rimg (Di.j, cm) cua cdc Trang thai rimg trfing: la rimg moi trfing Irang thai rimg nghien aiu nen duong kinh binh quan kha thSp trung binh - Duong kinh cay la chi tieu cdu tnic phan anh liT,2 cm va dao dong tir 6,9 cm d8n 7,3 cm; he sire sinh trucmg cua cay rimg. No lien quan dfa s6 bi8n dpng dao dpng tvr 8,3% d i n 14,5%.
nhieu nhan t6 cSu tnic khac va qua do anh huong Rimg tre niia: duong kinh binh quan la den hieu qua moi tmong cua rimg. 12,1 cm he s6 bi6n dpng dao dpng tir 12,3%
Trang thai rimg ngheo: tai cac mo hinh den 30,1%.
duong kinh trung binh dao dpng tir 13.2 cm Rimg trung binh: co duong kinh binh quan den 21 cm, he so bi8n dpng kha cao dao dpng la 20,6cm va chiing dao dpng tir 16,2cm dSn til 44,9% den 69,7% va trung binh la 56%. 26,6cm; he s6 biSn dpng dao dpng tir 34,1%
Dieu nay chiing to nhan t6 duong kinh co mirc d8n 70,9%. Miic dp phan hoa v6 ducmg kinh dp phan hoa cao va kk qua diSu tra cho thiy trung binh cua rimg trung binh cao.
nhung mo hinh co duong kmh trung binh cao chiiu cao cua cay rimg (Hvn) cda cic thi mat dp cay cao cung thjp hon. ,rg„g thai rimg nghien dm
Trang thai rimg phuc hoi: duong kinh ngang Tiing cao la tim la chSn dau tien phat huy nguc cua cac mo hinh dao dpng tit 12,2 cm dSn vai tro bao ve d i t cua rimg va chiSu cao cua 17,6 cm vol he so bien dpng dao dpng tir tan rimg cung anh huong dSn kha nang ch6ng 32,5% den 72,9%. Mirc dp phan hoa chiSu cao xoi mon. Cay rirng co chi& cao cang ldm thi trong cac mo hinh co su khac biet ro ret. nhimg hat nuoc mua roi xudng co siic cong 12 TAP C H i KHOA HQC VA CONG N G H E LAM NGHIEP SO 1-2015
Ldm hoc pha nhimg hat dat cang cao va ddng chay men
than cdng cang manh dan den lap d i t tren mat va cac tang dat ben dudi de bi pha huy k6t ciu nen kha nang bi xdi mdn se cao hon. Tuy nhien, neu rimg cd nhieu ting tan hay cay rimg cd muc dp phan hda ve chieu cao cang cao thi kha nang lam ban che xdi mdn se cao hon nhirng khu rimg cd miic dp phan hda th%).
Chieu cao trung binh cua cae trang thai rimg khdng cao, dao ddng tir 4,7ra d^n 12m, trong dd rimg trung binh va rimg tre nira cd chieu cao binh quan cao nhat va t h ^ nhat la rirag trdng,
Duong kinh tdn vd do tdn che nghiin cdu Dudng kfnh tan va dp tan che bieu thi cho can tnic ciia rimg tren mat phang nam ngang va the hien dien tfch ddn nude ciia tan rimg ed tac dung lam giam dang ke lugng nude tac ddng tryc tiep den mat dat rung. Tuy nhien, tac dung bao ve dat cua tan rimg cung chiu anh hudng eua chieu eao tan. Neu tan rimg cd chieu eao so vdi mSt dat Idn thi mua dudi tan rirag khdng khae so vdi mua ngoai dat trdng, tham chf gipt nirdc tir tan rimg cdn cd ddng nang Idn hon mua tu nhien neu loai cd phien la to. Luc nay tae dung chong xdi mdn chi cdn Iai la giam dupe lugng nude rai xudng tan rimg.
Ngoai trang thai tre niia, thi dudng kinh tan ciia cac cay gd tang cay cao trong eac trang thai giao dpng trong pham vi kha cao tir 1,6 - 5,1m thap nhat d rimg tre niia, rimg trdng va cao nhit d rirag trung binh.
+ Bg tdn che TC (%) trung binh cua cdc trgng thdi nghiin ciiu
Dp tan che d cac trang thai rimg khdng cd su khac biet nhieu, dao ddng binh quan tir 0,55 den 0,66. Trang thai rung trdng cd dp tan che cao nhat va thap nhat la trang thai rimg phuc hdi va dit trong.
Mat do cdy d cdc trgng thdi
Mat dp cay d cac trang thai ciing cd sir khac biet tuong ddi ro. Ldn nhat d trang thai tre nua 3.106 cay/ha. Rirng trong mat dp cay kha cao, binh quan la 1.967 cay/ha. Rimg ngheo mat dp binh quan la 971 cay/ha. Rirng phuc hdi mat dp binh quan la 1.087 cay/ha va thap nhat la rimg trung binh mat dp rung binh quan la 841 cay/ha.
3.1.2. Ddc diim thirc vgt tang thdp Ldp thyc vat ting thap dudi tan rimg chu yen gdm cay bui, tham tuai va cac cay con ciia nhung cay gd ldn. Tuy nhien, so vdi cay bui tham tuoi, sd lugng cay tai sinh thudng khdng nhieu va khdng cd vai trd thuc su quan trpng vdi kha nang ehdng xdi mdn bao ve dat. Thuc vat tang thap cd vai trd quan trpng vdi viec bao ve dat ciia cac trang thai rimg. Nd lam giam ddng nang cua mua xudng mat dat rimg giir cho mat dat toi xdp de tang siic tham nude cua dat rung, gdp phin ngan can lam cham ddng chay mat de tang co hdi tham nude xudng dat.
Ket qua tdng hpp sd lieu va phan tich thdng ke cho ket qua trung binh cho cae trang thai the hien d bang 4.2
Bang 4.2. Dgc diem tdng cay bui thdm tuai tgi cdc mo hinh nghiin cuu Trang thai
Dat trong Rimg ngheo Rimg phuc hoi Rimg trong Rimg trung binh Tre niia
Decile pbii
(%)
79,1 54,7 65,3 47.5 62,5 60,6
Ca\
Hcb (m) 0,0 1,3 0,8 0,7 1,2 1,2
bui Dtcb (cm)
0,0 0,9 0,6 0,6 1,1 1,2
Tham tiroi Htt (cm)
8,1 73,2 46,7 49,2 68,7 0,0
T . \ P CHI KHOA HOC \ . \ CONG .NGHE LAiM NGHIEP S O 1-2015 13
Lam hgc
Che phii C/o) cay bui thdm tucri a cac trting Mi Ty le che phu co su khac biet giira cac trang thai rimg hung bmh dao dpng tir 47,5% den 79,1%. Trong do trang thai rung tr6ng co ty le che phu cay bui tham tuoi thap nhat va trang thai dit trong co ty le che phii cay bui tham tuoi cao nhit. Nguyen nhan khong phai do dat trflng CO dp phi cao ma chu yeu la do cuong do chi6u sang manh. Nhcr vay, nhieu loai cay co ua sang CO thS d6ng thai phat trign lam tang dp che phii mat dit cua chiing.
Chiki cao cdy bui, thdm tuai duai cdc trang thdi rimg
Trang thai rimg ngheo co chieu cao cay bui tham tuoi cao nhit, cay bui binh quan cao 1,3 m va tham tuoi binh quan cac mo hinh cao 73,2 cm.
Khu vuc dit U6ng khong co cay bui va rimg tre niia lai khong co ldp tham tuoi.
Trang thai dit tr6ng mac dii khong co lop cay bui va tham tuoi chi cao 8,1cm nhung lai CO ty le che phu len d6n 79,1% la co la tre nen kha nang ban che xoi mon se tuong doi tot.
Trang thai rimg trong vi thuong xuyen dupe cham soc va phat dpn thuc bi nen chieu cao ciia cay bui kha thap, binh quan co 0,7 m va
chieu cao tham tuoi binh quan co 49,2 cm.
Nhu vay, trang thai dit trdng, rimg trong va trang thai rimg tre niia cay bui kem phat trien do qua trinh xii ly thuc bi hang nam.
Chieu cao tham tuoi o cac trang thai rirag tir nhien co xu huong cao hon so voi rimg trong va dat trong. Bien dpng ciia chieu cao cay bui tham tuoi trong khu vuc khong chi phu thupc vao di^u kien tu nhien ma con phu thupc vao cac tac dpng tir nhirng hoat dpng canh tac cua nguoi dan.
3.1.3. B4c diim ldp thdm kho
Lap tham kho la lop bao ve cuoi ciing cua mat d i t co tac dung hap thu mpt phan nude mua va ngan can dong chay khi phan huy chiing tang lupng miin cung nhu lam tang dp xfip ciia dit. Ldrp tham kho cung la noi tru ngu cua nhi8u loai sinh vat, vi sinh vat, nam, giun... tao nen dp phi nhieu cho dat. Cac hang hdc do giun va dpng vat dat tao nen la noi chira nuijc khi mua xudng. Do do no co anh huong d i n qua trinh thuy van va kha nang gifi nuoc, ehdng xoi mon cua he sinh thai rimg. Ket qua tong hop s6 heu va phan tich thong ke cho ket qua trung binh cho cac trang thai the hien a bang 4.3
Bang 4.3. Khoi luong thdm kho d cdc trgng thdi rirng nghien cuu
Trang thai Dat trong Rimg ngheo Rimg phyc h6i Rimg trong Rimg trung binh Tre niia
TK (%) Mtk (kg/ha)
69 59 73 82 69 75
585 2,733 3,150 4,517 4,095 4,717 Khoi lupng tham khd, vat rung (j cac trang
thai trong khu vuc nghien ciiu giao dpng d miic ftrong ddi ldn 200 - 6.600 kg/ha. Khdi lupng vat rung thip nhit o trang fliai dit trdng vdi khoi lupng 585 kg/ha tiip theo la trang thai rimg ngheo 2.733 kg/ha ldn nhit d trang thai
rirng tre niia 4.717 kg'ha. Voi trang thai dat trdng sir phan bd tham khd theo khdi lupng la khdng d8u so vdi cac trang thai rimg khac, nhung vd do che phu tham khd la tuong ddi ddu so vdi cac trang thai nghien ciiu
Ty le che phu mat dit cua ldp tham khd TAP C H i KHOA H Q C VA CONG N G H E L A M N G H I f P SO 1-2015
Ldm hoc
khdng cd khae biet ldn giua cac trang thai thuc vat. Rimg trdng cd ty le che phu eua ldp tham khd cao nhat, trung binh dat x i p xi 81,6%, rimg ngheo cd ty le che phii thap nhat, tnmg binh la 59,1%, d dit trong la 69,4%. Phan tich thdng ke cho thay su khac biet ve ty le che phii eua tham khd tren mat dat lien quan mat thiSt den dp tan ehe tang cay cao, phuang trinh phan anh mdi lien he:
CpTK = 23.03+ 0,79*TC vdi R = 0,71 (1) Bang 4.4. Cdc tinh chdt vpt ly cabdn
3.2. Dac diem xdi mdn d u d i cac trang thai r i m g tai KBTTN Thirgng T i l n
3.2.1. Bdc diem tinh chdt vgt iy cua ldp ddt mat tai khu vuc nghiin cuu
Tinh chat vat ly dat cd tac dung quyet dinh den lugng am, nhiet dp, chat dinh dudng, khdng khf dat, anh hudng true tiep den dp phi dat. Trong ndi dung cua luan van chi xet den cac tinh chat vat ly co ban bao gdm: dung trpng, ty trpng, dp xdp.
cua lap dot mat tm khu vuc nghiin cuu Traug thai
rirng
Ty trong (d, g/cm3)
Dung trong (D,
g/cm3) Do i m (W,%) Do xop (X%) Dat trijng
Rimg n ^ e o Riing phyc hdi Rimg trdng Rimg trung binh Tre nua
2,60 2,72 2,62 2,67 2,70 2,72
0,90 0,74 0,84 1,03 0,79 0,83
65,15 64,58 43,49 39,59 51.84 62,21
65,48 72,85 68,01 61,26 70,55 69,53 a. Ty trgng
Ty trpng la tri sd ean thiet de tinh dp xdp cua dat va nd phan anh mdt each dinh tinh thanh phan khoang vat va ham lugng chat hiiu eo trong dat. Ty trpng trung binh cua cae trang thai dao dpng tir 2,60- 2,72 g/cm^ cao nhat d 2 trang thai dat trdng cay bui va rCmg tre nira. Muc dp dao dpng ty trpng giua cac trang thai rimg khdng nhieu.
b. Dung trgng
Dung trpng cua dat thudng nhd hon so vdi ty trpng vi the tfch dat khd kiet dugc xac dinh d day bao gdm cac hat dat ran va cac khe hd tu nhien cd trong dat.
Dung trgng cua dat phu thugc vao cap hat c a gidi, dp chat va ket cau cua dat. Cac loai dat tai xdp, giau chit huu co va mim thudng cd dung trpng nhd va ngupc lai nhiing. Dung trpng cua d i t dao dpng trong khoang tir 0,74 - 1,03 g/cm"
trong dd trang rimg trdng co dung trpng binh quan Idn nhat va trang thai rung ngheo cd dung trpng nhd nhat. Ket qua so sanh dung trpng tang
dat mat giua cac trang thai rimg nghien ciiu dugc minh hpa nhu hinh sau.
c. Bp xop
Dp xdp la chi tieu quan trpng dimg de danh gia dat, dp xdp phan anh ket can ciia dat "dat cang tdt, dp xdp cang eao". Mat khac, dp xdp anh hudng quyet dinh den che dp nhiet, che dp am va che dp khdng khi ciia dat. Dac biet vung ddi niii neu dat cd dp xdp cao thi phan ldn nude mua dugc tham xudng sau, ban che hien tupng chay tran tren mat dat va giam thieu dupe xdi mdn. Vi vay, day la can cii quan trpng cho viec quyet dinh cac bien phap tac dpng vao dat, hen quan den qua trinh xdi mdn va nia trdi dat.
Nhu vay, ket qua dieu tra va phan tich tfnh chat vat Iy dat cho thay tfnh chat vat Iy dat trong khu vuc nghien cuu dao ddng trong pham vi khdng ldn. Khi thdng ke theo cae loai trang thai, da nhan thay sy khac biet \ l dp xdp giira cac trang thai ehi trong khoang 5-10%.
Trong dd trang thai rimg trdng cd dp xdp nhd TAP CHI KHOA H O C \ A CONG NGHE LAM N G H I E P SO 1-2015 15
Ldm hgc ^ = _ ^ = ^ = ^ ^ = ^ = ^ = nhit la 61,26% va rimg ngheo cd dp xdp cao nhit la 72,85%. Nguyen nhan cd the do dat dai d trong khu vuc chua chiu nhiSu tac ddng nhieu tir cac boat ddng canh tac, sinh song cua ngudi dan dia phuong.
3.2.2. Bdc diem che dp mira tai khu virc nghiin cuu
Mua la mpt trong nhung nhan td cd tac dpng true ti8p d§n qua trinh xdi mdn; ddng thdi anh hudng den cau tnic, ngoai mao va dpng thai phat triln cua ldp tham thuc vat.
Nghien ciiu phan bd mua la theo ddi su phan bd cua lupng mua roi vao cac thang, cac khoang thdi gian mua. Biet dugc dieu nay cd y nghia quan trpng trpng viec du bao ddng ehay, xoi mdn dit va xac dinh cac bien phap phdng ehdng thich hgp.
+ Miia mua d khu vuc nghien cuu cd the dupe xac dinh tir thang 5 den thang 10, keo dai 6 thang lien tuc trong nam vdi lupng mua thang ldn hon 1.598 mm. Lugng mua binh quan ldn nhat tren thang trong miia mua la 337mm (thang 8), nhd nhat la 165 mm (thang 10). Vao miia khd, lugng mua binh quan thap nhat tren thang bien ddng tir 12 mm (thang 1)
den 72 mm (thang 4).
3.2.3. Bia hinh tai khu vuc nghiin ciru Dia hinh cd anh hudng tryc tiep den xoi mdn dit, dac biet la dp ddc. Rimg tai khu vuc dugc phan bd tren dat cd dp ddc tir nhd din ldn, dia hinh hi chia cat nhieu bdi eac dong, khe. Dia hinh chu yeu la ddi cao va niii thap, nhieu khu vuc cd dp ddc ldn ban 35". Cac mo hinh nghien cuu, dp ddc binh quan d cac tr^g thai deu ldn hon 20° (tru khu vyc dit tr6ng) nhu vay khu vuc nghien cuu cd dia hinh phuc tap va dp doe ldn nen se phan anh tot vai tro cua cac yen td tham thyc vat khac nhau den luong xdi mdn dudi rung.
3.2.4. Bdc diem xoi mdn dudi cdc trgng thdi rung tgi KBTTN Thuong Tiin
Xac dinh dupe lupng dat xdi mdn la npi dung va muc dich quan trpng cua nghien cuu xdi mdn dat. Tir dd tien hanh phan cap chi tieu nay de cd cac bien phap tac ddng phii hgp cho timg cap dp xdi mdn khac nhau.
Tdng hpp so lieu ve lupng xdi mon dudi cac trang thai rirng theo cac md hinh quan trac cho thay, xep theo thu ty giam dan vS lupng xdi mdn ta cd trinh ty.
Bang 4.7. Luang dot xdi mdn dudi cdc trang thdi thdm thue vat nghien cuu tai KBTTN Thuong Tien TT
1 2 3 4 5 6
Trang thai Dat trong Rimg ngheo Rimg phuc hoi Rimg trong Rimg Uung bmh Tre nira
Do doc (d9) 19,5 21,75 23 20,75 22,25 22,75
Mxm (kg/ha) 55,3 91,9 154.7 22,3 68,5 115,3
Mxm (kg/ha/thing)
27,65 45,95 77.35 11.15 34,25 57,65 Mdi lien he kha rd giira dp ddc cua cac tiang
thai rirag nghien cihi va lupng xdi mon do duoc dudi rung, mpt quy luat chung do la khi dp ddc tSng thi lupng xdi mon dudi rirag ciing tang theo. Dieu nay hoan toan phii hpp vdi thuc ti quan trac: rung phuc hoi cd luong xdi mdn cao nhat thi cung cd dp ddc tnmg bmh cao nhit 23°
dp, tiep theo den cac trang thai rung tre niia va rimg ngheo cd dp ddc lan lupt la 22,75° dp va 21,75° dp; quy luat nay la co su sai khac ddi vdi trucmg hop dit trdng va rimg h-dng; nguyen nhan co thd do ddi vdi hai trang thai nay ngoai yiu td dp ddc cdn chiu su chi phdi manh me ciia nhiiu ydu td khac nhu: cau true ldp phii....
TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP S6 I-20I5
-l,-»;'V.r-i£,hja
' t-^
Ldm hgc
Hinh 4.1. Lien he giua dp ddc trung binh vd lu0tg xdi mon dudi rimg
Hinh 4.2. Lien he giira dp xop ldp dat mat vdi luffng xdi man dudi rirng
Ket qua phan tich thdng ke cho thay, lugng xdi mdn dudi cac trang thai rimg khdng nhimg lien he vdi nhan td dp ddc dudi rimg ma cdn cd tuong quan tuang ddi chat vdi dp xdp cua Idp d i t mat dudi rimg. Dp xop ldp dat mat la yiu td nhay cam va rat de bi bien ddi do cac tac nhan tir ben ngoai, nd la mdt trong nhirng nhan td phan anh tdt tinh chat cua dat rimg va muc dp tac ddng ctia con ngudi thong qua cac hoat ddng canh tac.
3.3. Anh hudng cua t h a m thyc vat t i n g t h a p den cirdng do xdi mon dudi cdc trang thai r i m g tai KBTTN T h u o n g Tien
Dac diem cua tham thyc vat tang thap dupe dai dien bdi he thdng: cay byi, tham tuoi, cay tai sinh va ldp tham muc dudi rimg; chinh vi vay de danh gia dupe vai trd ciia cac thanh phin trong tham thyc vat tang thap anh hudng den lupng xdi mdn dudi rimg de tai tien hanh nghien cihi anh hudng cua timg nhan td cau tnie don le, cung nhu tdng hpp cua tham thuc vat ting thip d i n lugng xdi mdn dudi rirag.
+ Anh huong ciia chieu cao lop cdy bui den lugng xoi mon du&i rimg-
S6 lieu dieu tra cho thay, chieu cao bmh quan ciia ldp cay byi dudi cac trang thai rirag nghien cuu thyc sy tdn tai mdi lien he tuyen tfnh mpt ldp ddng bien vdi lugng xdi mdn dudi cac trang thai rirag. Khi chiSu cao cua tang cay bui cao thi ddng nang cdng pha mat dat cua cac
cao, lam cho kha nang ban pha va lam toi xdp cac ket cau dat cang manh, tir dd khi xuat hien ddng chay mat lugng dat rimg bi cudn trdi cang nhieu, lam cho lugng xdi mdn dudi rimg tang. Phuong trinh phan anh mdi lien he nay dugc xac dinh nhu sau:
Y - -23,5 + 84,99*X vdi R = 0,74 (2) -r Anh huong cua duong kinh tdn lop cdy bui din lugng xoi mon duoi rimg
Lupng xdi mdn dudi rimg ciing cd mdi lien he ddng biSn vdi dudng kfnh tan, mdi lien he nay dupe md phong qua phuang trinh tuyen tinh 1 ldp, nhung miic lien he chi la tuong ddi chat:
Y = 26,70+ 43,83*X vdi R = 0,54 (3) + Anh hudng cua chieu cao lop thdm tuoi den lugng xoi mon duoi rimg
Ket qua phan tfch thdng ke va md hinh hda cho thay, thuc su tdn tai mdi lien he tuyen tfnh mpt ldp ddng bien giira chi tieu chieu cao ldp tham tuai vdi lupng xdi mdn dudi rimg, nhung mdi lien he nay la khdng that chat che va chi d miic dp vira. Dieu nay cd nghia khi chieu cao cua ldp tham tuoi tang thi ciing gdp phan lam cho lugng xdi mdn dudi rimg tang, tuy nhien mdi lien he ddng bien nay la chua that sy ro net khi dung don le trong nghien ciru nay.
+Anh hirong cua do che phu thdm tuoi, cdy bui din lugjigxdimon duoirimg
Mdi lien he giiia lupng xdi mdn dudi rirag vdi dp che phu cua tham tuoi, cay bui la mdi lien he tuyen tinh mdt ldp va nghich bien; tuc gipt nude hinh thanh tren ldp cay bui se cang
TAP CHI KHOA H O C VA CONG N G H E LAM N G H I E P SO 1-2015 17
Ldm hgc
la: khi dp che phii cua ldp tham tuoi cay bui tang len thi lupng xdi mdn dudi cac trang thai rirag giam di. Nhu vay, khang dinh vai trd quan trpng cua ldp tham tuoi cay bui dudi rimg ddi vdi kha nang giir nude, bao ve dat cua cac trang thai rimg khae nhau. Day la can cii cho viec de xuat va xay dyng eac bien phap ky thuat lam sinh tac ddng vao cau tnic rimg nhim nang cao kha nang phdng hd ciia rimg.
Phuong trinh phan anh moi lien he giira dp che phu cua ting tham tuoi, cay bui vdi lugng xdi mdn dudi rimg duge xac dinh nhu sau:
Y = 129,37 - 0,836*X vdi R - 0,66 (4) + Anh huong ciia lop thdm kho den lugng xoi mon dudi rimg
Ldp tham khd dudi rimg la tam la chan bao ve cudi ciing cho ldp dat dudi rimg ddi vdi sir cdng pha ciia cac h^t mua chfnh vi vay nd cd mdi lien hp tuong ddi chat vdi lugng xdi mdn dudi rimg. Ket qua phan tfch thdng ke sd lieu quan trac cung da khang dinh, thyc sy tdn tai mdi hen he tuyen tinh 1 ldp nghich bien giira dp che phii cua ldp tham khd vdi lupng xdi mdn dudi rirag. Nhu vay, khi dp che phu cua ldp tham khd dudi rirag cang tang thi lugng xdi mdn dudi rimg cang giam va hieu qua bao ve dat ciia cac trang thai rirag cang dupe phat huy. Phuang trinh phan anh m6i lien he nay dupe xac dinh cu the nhu sau:
Y - 1 8 2 , 6 - l , 7 i 8 * X vdi R = 0,67 (5) + Anh hu&ng cua chi tiiu tong hgp phdn dnh cdu true cua lop thuc vgt tdng thdp din lugng xoi mon duoi rung
Trong nghien ciiu nay su dung chi tieu tdng hpp phan anh dae diem cau true cua ldp thyc vat tang thap dudi rimg la:
CTTH1 = (Hcb + Htt + Hts)/3 ; CTTH2 = (CPtt+CPcb)/2
Phan tich tuong quan, xae dinh mdi lien he giira eac chi tieu ciu friic tdng hop CTTHl, CTTH2 va dp che phii ciia ldp tham khd dudi rirag (TK) cho thiy thyc sy tdn tai mdi lien he 18
tuyin tinh nhiiu ldp giira cac chi tieu nghien eihi ycri lupng xdi mdn dudi cac trang thai tham thyc vat rimg tai KBTTN Thugng Tiin.
Phuong trinh tuong quan phan anh mdi lien he nay dugc xac dinh nhu sau :
Y - 136,28 + 0,407*(Hcb+Htt+Hts)/3- l,462*((CPeb + CPtt)/2)- 0,568*TK
vdi R - 0 , 8 9 (6)
3.4. D^ xuat mpt sd giai p h a p gdp phan giam thieu cudng dp xdi mdn d u d i cdc trang thai rirng tai KBTTN T h u g n g Tien
Nghien cuu de xuat mpt sd giai phap nang cao kha nang bao ve va phat trien rirag ddng thdi phat huy dugc chiic nang phdng hp ching xoi mdn bao ve dat cho cac trang thai nmg tai KBTTN Thuong Tiin tinh Hda Binh, cu thi nhu sau:
+ Tien hanh (Juy hoach su dung dat thfch hpp vdi dieu kien dia liinh tai KBTTN Thupng Tien;
+ Tang cudng nhirng bien p h ^ ky thuat de han che xdi mdn va canh tac bin vimg tren dat ddc;
+ Ngan cam nhimg hanh ddng lam thiet hai rimg, tich cue phuc hdi va trdng them rung
+ Nang cao nhan thiic va kien thiic ve chong xdi mdn bao ve dat;
+ Duy tri cau tnic hgp ly eiia ldp tham thuc vat tang dudi dac biet ddi vdi cac trang thai rimg san xuat va dat sii dyng cho muc tieu phat trien ndng lam ket hgp, canh tac nuong ray cua ngudi dan tai KBTTN Thupng Tiin.
IV. K E T LUAN
Ket qua nghien eiiu da chi ra ring, Idp tham thyc vat tSng thap thyc sy tdn tai mdi lien he giua cudng dp xdi mdn dudi cac trang thdi rimg tai KBTTN Thugng Tien vdi dac diem cau tnic ciia Idp tham thuc vat ting thip dudi rimg.
+ Anh hudng cua chieu eao, dudng kfnh tan cua ldp cay bui vk chiiu cao ciia Idp tham tuoi den hrpng xdi mdn dudi rimg la mdi quan he tuyin tinh mpt ldp ddng biin.
+ Anh hudng cua dp che phii tham tuai, cay bui va dp che phii ciia tham khd din lupng xoi TAP C H i KHOA H O C VA CONG NGHE LAM N G H I E P SO 1-2015
Ldm hgc mdn dudi riing la mdi quan tuong ddi chat theo
dang phuong trinh tuyin tfnh mot ldp nghich biin.
+ Anh hudng cua chi tieu tdng hpp phan anh cau tnic ciia Idp thyc vat ting thip din lugng xdi mdn dudi rirng dupe khang dinh la thuc sy tdn tai dudi dang mdi quan he tuyin tfnh nhieu Idp, vdi su tac ddng cdng hudng cua nhieu nhan td phan anh dac diem cau tnie ciia ldp tham thue vat ting thap dudi rimg.
Y - 136,28 + 0,407*(Hcb + Htt + Hts)/3 - l,462*((CPcb + CPtt)/2)-0,568*TK
vdi R = 0,89 (6) TAI LIEU THAM KHAO
1. Pham Ngoc Dung (1993). Rung voi tac dyng dong
chay. Tgp chi ldm nghi^, 93 (solO), tr. 14-16.
2. Pham Van Dien (1999). Budc ddu nghien ciiu dgc diem thuy vdn cda mot sd thdm thuc vgt rung ldm ca sd cho viec xdy dung tieu chudn rung giir nuac viing .xung yeu Ho thuy difn Hda Binh. Luan van TTiac Sy tnrong Dai hoc Lam nghiep. Ha Tay,
3. Vo Dai Hai (1996), Nghien am cdc dang cdu tnic hop ly cho rimg phdng hg ddu ngudn a Viet Nam. Luan an Pho tien s j khoa hQC Nong nghiep - Vien Khoa hoc Lam nghiep. Ha Noi.
4. Dao Van Hanh (2007). Xdc dinh he sd xdi mdn ddt vd he so xoi mon do mua tai khu vtrc rimg phdng ho ddu nguon huyen Nhu Thanh - tinh Tlianh Hoa. Khoa lu5n tot ngjiiep, Trucmg dai hpc Lam N ^ i e p , Ha Noi.
S.Bonell M(1993). Progress in the urderstanding of runoff generation dynamics in forests. Journal of hydrology, 93 (1); pp. 99-104.
IMPACT STUDY OF LOW RISE TO VEGETATION INTENSITY OF SOME EROSION STATE FORESTS
IN NATURE RESERVE THUONG TIEN - HOA BINH
Pham Thi Kim Chi, Bui Hung Trinh, Nguyen Van Tuyen SUMMARY
The paper presents some results reflect the relationship of the effects of low level vegetation to soil erosion intensity under some state forests in forest nature reserves Thuong Tien - Hoa Binh: (i) Effect of way tall shrub layer to the amount of erosion under forest is a class of linear equations covariates at relatively tight contact:
Y= -23.5+84.99*X with R= 0.74; (2) Effect of canopy diameter shrub layer to the amount of erositm under forest is a class of Hnear equations covariates at relatively tight contact:Y = 26.7+ 43.83*X with R= 0,54, (3) The influence of vegetation cover , shrub forest to the lower amount of erosion is a class of linear equations is inverse: Y= 129.37-0.836*X with R=^.66; (4) Effect ofdry carpet layer to the lower amount of erosion forest is a class of linear equations inverse Y=182,6-1,718*X; (5) Effect of indicators reflecting the structure of the lower layer of vegetation to the amount of erosion under forest.
Keywords: Erosion, forest conditions, low level vegetation, nature n
Ngudi phan bien PGS.TS. Ngd Binh Qui Ngay nhan bai
Ngdy phan bien Ngay quyet dinh dang
16/1/2015 : 28/1/2015
15/3/2015
TAP CHI KHOA HOC V A CONG NGHE LAM NGHIEP SO 1-2015 19
