III. Ket qua nghien ciru va thao luan
3.3.Nhdm ddt man
d My San, Ninh San, Ninh Thuan
3.3.Nhdm ddt man
Nhdm da't man d Ninh Thuan cd dien tich 3.666 ha, chiem 1.09% dien tich tu
nhien, phan bd chu ye'u d cac huyen Ninh Hai (2.638 ha), Ninh Phude (835 ha) va Phan Rang - Thap Cham (148 ha). Do dieu kien hinh thanh trong viing khi hau ban khd han nen a Ninh Thuan cd ca da't man noi dia va dat man ven bien.
Nhdm dat man kiem dugc lay tai thon Phii Thi, xa My San, huyen Ninh San va phudng Dd Vinh, Thi xa Phan Rang Tinh Ninh Thuan la dat thit pha cat vdi ham lugng cat la 78.27%, limon 11.56%, set 10.17% va cat la 65.24%, limon 11.66%, set 23.10%, theo thii tu. Dat cd phan ling chua nhe (pH^ci = 5.6) d My San va kiem vira (pH^ci = 8.41) 0 Phan Rang. Ham lugng chat hiru ca ngheo d My San (1.524%) va rat ngheo d Phan Rang (0.469%). N, P, K tdng sd tai cac mSu da't nghien ciiu deu d miic rat ngheo. Dung tich ha'p phu va trao ddi cation d miic trung binh (12.47 va 11.42 mgdl/lOOg dai)
Hien tai nhdm da't man kiem d My San mdi chi trdng liia dugc 1 vu nhd vao dieu kien nude trdi, cdn d phudng Dd Vinh, Thi xa Phan Rang chu yeu cd suang rdng phat trien. Nhin chung ham lugng cac chat dinh dudng cua loai dai nay d miic thap. Dai thudng phan bd d nhung khu vue khd khan ve ngudn nude tudi nen de gia tang he sd cung nhu hieu qua su dung dat, cSn phai dau tu thiiy Igi, giai quyet nude tudi de bd tri tang vu cay trdng hoac cung cap nude man de nuoi trdng thuy san nude man.
IV.Ket luan
1. Nhdm dat dd, xam nau va dai man kiem vung ban kho han Ninh Thuan cd thanh phan ca gidi nhe den trung binh, chii yeu la dai cat pha thit. thit pha cat va pha set. Phan iing cua dai d muc rai chua, chua vira den trung linh tai
cac phau dien dai khac nhau tiiy thuoc vao dieu kien canh tac. Do bao hda
baza cao, dung tich hap phu va trao ddi cation cua dai cao. Ham lugng chai hiru ca va cac yeu td dinh dudng da lugng N, P, K can thiei cho cay trdng chi dat d mu-c ngheo den gan trung binh.
2 Tinh trang thieu nude va ham lugng cac chai dinh dudng ngheo nan la mot trong nhirng tac nhan han che qua trinh san xuat nong nghiep tai vung nay.