Effects of soymilk root irrigation on the growth of flue-cured tobacco
and bacterial community in soilDai H.X.1; Yang J.J.2; Li L.3, Xi J.Q.1; Liang T.B.1; Wang J.W.1; Chen Y.C.2; Su X.H.*2; Zhang X.*3
1. Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450001, China
2. Company of Sanmenxia City of Henan Provincial Tobacco Company, Sanmenxia 472000, China
3. Institute of Plant Nutrition, Resource and Environment, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China.
Introduction
Soymilk root irrigation (SRI, traditional soymilk and fermented soymeal), a topdressing technology with local characteristics for soil conservation, has became a routine
agricultural technical measure in tobacco planting area of western Henan province for more than 20 years. To unravel the effects of SRI on the growth of flue-cured tobacco, pot
and field experiments were performed to analyze soil nutrient status, agronomic traits, root growth, soil bacteria counts and bacterial community structure. The results showed
that the contents of soil nutrients such as alkali-hydrolyzed N, available P and available K remained relatively high in the middle and late stages of SRI. The growth of tobacco
root and leaves were promoted after SRI. The abundance of dominant bacteria in soil varied significantly among different treatments at the early stage of SRI, however, similar
dominant bacteria abundance was observed in the middle and late stage of SRI. The bacteria number increased significantly, and the relative abundance of twenty-two soil
functional bacteria categorized mainly in nutrient cycling, secretion plant growth regulators, and inhibiting pathogens exhibited great increment in the early stage of SRI.
Therefore, SRI may improve the yield and quality of flue-cured tobacco by increasing soil nutrients contents, increasing the relative abundance of beneficial functional bacteria,
improving soil micro-ecological environment, and promoting the growth of root and leaf of flue-cured tobacco.
.
Main results
Conclusion➢The contents of soil protein and active carbon increased significantly in the early stage of SRI, and the contents of
alkali-hydrolyzed N, available P and available K remained relatively high in the middle and late stages of SRI.
➢The growth of tobacco root and leaves were promoted after SRI.
➢At the early stage of SRI, the number of bacteria increased rapidly, and the abundance of dominant bacteria in soil
varied significantly among different treatments.
➢At the early stage of SRI, the relative abundance of various soil functional bacteria involved in nutrient cycling,
secretion plant growth regulators, and inhibiting pathogens increased significantly.AcknowledgmentsThis study was financially supported by the Henan Tobacco Company Research Project (2018410000270036), the China Tobacco Henan
Industrial Co., Ltd. Project (2019410000340029), and the Sanmenxia company project of Henan Tobacco Company (201641120024056).
Tab. 1 The nutrient composition of traditional soymilk and fermented soymeal(g/kg)
DaysTreat
ment
Alkali-
hydrolyzed
N
Available
P
Available
K
Organic
matters
Available
Fe
Exchang
eable Ca
Exchangea
ble Mg
Active
carbon
Soil
protein
index
CK 286.3 a 31.4 a 256.6 a 17.7 a 21.2 a 3103.2 a 644.8 a 357.1 a 1.44 a
0 d T1 275.7 a 29.4 a 221.7 a 16.8 a 19.5 a 2912.6 a 653.6 a 356.3 a 1.30 a
T2 288.1 a 30.8 a 211.9 a 17.2 a 18.2 a 2921.4 a 632.4 a 364.9 a 1.39 a
CK 280.6 a 30.5 a 241.9 a 17.2 a 20.7 a 3058.7 a 686.1 a 365.2 b 1.72b
5 d T1 294.4 a 26.8 a 234.3 a 18.4 a 18.2 a 2824.6 a 661.1 a 401.7 a 2.56 a
T2 294.8 a 31.1 a 244.2 a 17.6 a 17.9 a 2873.9 a 602.6 a 408.9 a 2.60 a
CK 220.2 b 17.7 c 218.0 b 16.7 a 16.5 a 2540.7 b 514.2 b 325.3 a 1.64 b
20 d T1 268.2ab 24.4 b 235.5 b 17.9 a 16.9 a 2863.4 a 677.5ab 366.0 a 1.99 a
T2 300.3 a 30.0 a 307.2 a 17.1 a 19.0 a 3154.4 a 779.0 a 358.7 a 2.01 a
CK 245.6 a 20.1 b 289.4 a 17.6 a 21.2 a 2743.7 a 625.5 b 304.0 a 1.34b
35 d T1 287.9 a 26.1 b 279.6 a 17.4 a 20.3 a 2575.5 a 644.4 b 330.8 a 1.68 a
T2 282.3 a 32.7 a 299.4 a 18.2 a 21.3 a 3066.9 a 740.0 a 319.7 a 1.54ab
CK 127.0 b 15.5 b 209.0 a 16.6 a 18.6 a 2902.0 a 611.3 a 287.4 a 1.21 a
55 d T1 158.1 a 22.6 a 213.5 a 17.9 a 20.6 a 2806.9 a 662.5 a 319.3 a 1.24 a
T2 149.6 a 27.1 a 205.1 a 17.5 a 20.2 a 2732.7 a 612.0 a 322.5 a 1.20 a
CK 111.9 b 10.8 b 160.6 b 15.7 a 17.3 a 2823.8 a 552.6 a 223.4 a 1.05 a
75 d T1 163.3 a 18.3 a 191.7 a 16.2 a 18.8 a 2714.9 a 591.2 a 211.9 a 1.20 a
T2 168.9 b 20.8 a 187.9 a 16.9 a 20.4 a 2847.7 a 587.0 a 230.6 a 1.13 a
CK 112.9 b 5.0 b 146.8 b 9.9 a 18.6 a 2747.0 a 459.3 a 340.5 a 0.99 a
95 d T1 168.2 a 16.4 a 169.0 a 10.3 a 19.6 a 2530.1 a 402.4 a 361.6 a 1.21 a
T2 180.7 a 14.1 a 177.1 a 10.7 a 19.1 a 2733.2 a 401.1 a 353.2 a 1.23 a
Tab. 2 Effects of soymilk root irrigation on the soil nutrient contents in field(mg/kg)
Tab.3 Effects of soybean milk root irrigation on the agronomic characters of flue-cured tobacco in field
0
2
4
6
8
10
12
14
0 5 20 35 55 75 95
CK
T1
T2
Bac
teri
alam
ou
nts
(1
08
cfu
·g-1)
Fig. 1 Effects
of soymilk root
irrigation on
the number of
soil bacteria
Fig. 3 Comparison of Chao and Shannon indices of soil bacteria at 5 d (A, D), 35 d
(B, E) and 95 d (C, F) after soymilk root irrigation
Functions Bacteria CK T1 T2
Streptomyces 2.78 b 1.59 c 6.23 a
Rhodanobacter 0.92 b 2.03 a 1.61 a
Mizugakiibacter 0.68 b 0.23 c 1.32 a
Nitrospira 1.05 a 0.57 b 0.12 c
Massilia 0.45 b 1.65 a 1.20 a
Soil nutrient cycling
Gemmatimonas 1.07 a 0.45 b 0.33 b
Sphingomonas 0.33 b 1.39 a 0.20 b
Sphingobacterium 0.00 c 0.13 b 4.51 a
Chitinophaga 0.10 c 1.30 a 0.92 b
Klebsiella 0.01 b 0.04 b 3.53 a
Devosia 0.25 b 0.45 a 0.37 ab
Dongia 0.02 b 0.04 a 0.04 a
Rhodocytophaga 0.01 b 0.03 a 0.03 a
Cellvibrio 0.03 b 0.05 a 0.05 a
Secretion of plant
growth regulators
Bacillus 0.23 c 0.35 b 0.60 a
Pseudomonas 0.11 c 5.97 a 3.05 b
Pseudoduganella 0.05 c 1.77 a 1.04 b
Luteibacter 0.03 c 0.18 b 3.72 a
Inhibition of pathogenic
bacteria
Lysobacter 2.77 c 3.92 b 12.20 a
Pseudoxanthomonas 0.05 c 1.29 a 0.69 b
Mycobacterium 0.08 b 0.17 a 0.19 a
Bdellovibrio 0.01 b 0.03 b 0.05 a
Tab.5 Changes in abundance of soil bacteria at the early stage (5 d) of soymilk root irrigation(%)
Traditional soymilk Fermented soymeal Soymilk root irrigation
Items Organic
matters
Crude
fat
Crude
protein
Soluble
protein
Carbohy
drate
P Fe Ca K Small peptides and
amino acids
Traditional
soymilk
674.3 497.4 605.2 398.7 350.7 14.6 0.17 3.10 14.12 2.52
Fermented
soymeal
705.6 32.9 537.1 350.3 386.2 8.24 0.16 2.93 13.91 1.71
TreatmentHeight/
cm
Pitch/
cm
Laimosphere/
cm
Numbers of
leaves
Length of maximum
middle leaf/cm
Width of maximum
middle leaf /cm
Length of maximum
top leaf/cm
Width of maximum
top leaf/cm
CK 102.4 a3.68 a 8.15 a 21.4 a 62.3 b 23.5 a 50.4 a 19.8 b
T1 105.6 a3.73 a 8.24 a 22.0 a 64.2 a 24.6 a 50.6 a 21.4 a
T2 104.8 a3.75 a 8.27 a 21.9 a 64.4 a 24.8 a 51.2 a 21.5 a
TreatmentTotal root
length/cm
Surface
area/cm2
Average
diameter/mm
Length of per
volume root/(cm∙m-3)
Root
volume/cm3
Root dry
weight/g
CK 14067.12 b 2986.57 b 1.76 b 14088.76 b 52.55 b 7.81 b
T1 16861.83 a 3786.08 a 2.07 a 16943.51 a 72.68 a 9.37 a
T2 16137.72 a 3989.45 a 2.13 a 16217.14 a 74.55 a 9.48 a
Chao
index
Shan
non i
ndex
aCB
aE F
CK T1 T2 CK T1 T2 CK T1 T2
a
a
b
A
b
a
a
a
a
aD
a
aa
aa
aa
After 28 days of transplanting, tobacco seedlings were treated with water(CK), soybean milk (T1) and traditional soymilk in field (T2).
Means with the same letter are not significantly different at P = 0.05 among the 3 treatments at each of the 6 time points.
Tab. 4 Effect of soymilk root irrigation on the root growth characters of flue-cured tobacco in pot
b
a
ba a a
a b a a a a a
a
ba
b b ab b b b a a a ab
a
aba
b c b ca c a a b b
0102030405060 CK T1 T2
a a
a aa a a a a a a a a
a
aa
a a aa a a a a a a
a a
a a a aa a a a a a a
01020304050
a
aa
aa a
aa a a a a a
a
aa a a a
a a a a a a a
a
aa
a a aa
a a a a a a0
10
20
30
40
50
Ab
un
da
nce
(%
)
Fig.2 Abundances of bacterial communities at phylum level in tobacco-planting soils at 5
d (A,), 35 d (B) and 95 d (C) after soymilk root irrigation
A
B
C
2020
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