Fig.1 Characteristics of changes in soil microbial biomass C and
N under different optimal water and fertilizer management
Note: Different capital letters indicate significant difference between
different water and fertilizer control treatments in the same growth
period (p <0.05); Different lowercase letters indicate
significant difference between different growth periods under the same
water and fertilizer control treatment (p <0.05)
2.2
Effect of different water and fertilize optimal management on soil
enzyme activity change characteristics
Under the same optimal management of water and fertilizer, the
activities of soil urease, sucrase, acid phosphatase, and catalase
showed significant differences at different growth periods
(p<0.05), which increased first and then decreased with the
prolongation of the growth period of Panax notoginseng, and the
activities ranged from large to small in flowering period, fruiting
period, seedling period and rooting period. Tab.2 shows that the
activities of urease, sucrase, acid phosphatase and catalase are
2.86~9.52 mg.kg -1.d.-1,
17.12~68.79 mg.kg-1.d.-1, 2.14~8.2
mg.kg -1.d.-1 and 5.1~9.42
mg.kg-1.h-1, respectively. Under the
same optimal management of water and fertilizer, the active of urease,
sucrase, acid phosphatase, and catalase increased by 30.81% and
46.08%, 31.94% and 44.43%, 34.08% and 59.01%, 12.44%, and 37.86%
respectively from flowering period to flowering period. The soil enzyme
activities of W3F4 were higher than those of other treatments. The
rooting period of urease and catalase activities of W3F4 were 2.14 and
1.67 times of CK, respectively. The flowering period of sucrase and acid
phosphatase activities were 1.83 and 2.53 times CK. The soil water
content decreased firstly and then increased and then decreased with the
prolongation of the growth period. The maximum value appeared in the
flowering period , and the minimum value in the seedling period. The
difference between the flowering and seedling period of W3F4 was the
largest, 4.3%, and that of W2F3 was the smallest, 1.72%.
Under different water and fertilizer optimal management, soil urease,
sucrase, acid phosphatase, and catalase activities in the same growth
period showed significant differences (p<0.05). Soil urease,
sucrase, acid phosphatase, and catalase activities increased with the
increase of irrigation amount and fertilizer application amount. Soil
urease, sucrase, acid phosphatase, and catalase activities W3F4 at the
flowering period were the largest, increasing by 44.26%, 61.51%, 42.56
and 32.25% respectively as compared with the minimum value W1F1; Under
the same water and fertilizer optimal management, the soil enzyme
activities increased with the increase of fertilizer application amount,
and the activities of urease, sucrase, acid phosphatase and catalase in
W3F4 were the highest, which were 1.95, 1.69, 2.32 and 1.47 times of CK,
respectively.