沙漠研究 22-1, 103 -106 (2012 )"ICAL 1 / DT X"

Journal of Arid Land Studies－Refereed Paper－

Effect of Sulfur-humic Acid on Agricultural Production Including Grape
Growth on Saline-alkali Soil in Gansu Province, P. R. ChinaYuichi ISHIKAWA*1), Jun FUKUSHIMA1), Kenji SAKURAI1), Shiquan NIU2), Shiping WANG3), 4),
Mitsuhiro INOUE3), Takuro Shoji1), Atsushi HAYAKAWA1) and Shin HIDAKA1)
Abstract: Saline-alkali soil mainly spreading in the northeast China has a problem on low crop production caused from high electric
conductivity and low water potential by salinity and micronutrient unavailability by high pH. In order to improve saline-alkali soil,
usage of mixture of elemental sulfur and humic acid (hereafter referred to as “DS”) has been proposed. The objectives of the study
are 1) to clarify the mechanism how DS worked for soil improvement and 2) to evaluate DS on agricultural production including grape
seedling on saline-alkali soil in Gansu Province, P. R. China. As the results of a pot incubation trial concerning 1), all of soil pH in thethree locations decreased after 3 months. The reduction of pH show the tendency to be bigger as the initial soil pH was higher.
Effect of DS application depended on soil samples. Sulfate changes were not related with soil pH, therefore sulfate production waspartly accompanied with pH reduction. Results of Denaturing Gradient Gel Elecrophoresis (DGGE) showed that bacterial
community started to change as soon as 2 weeks after incubation, in addition that the difference between soils was large. 2) Grape
seedlings with DS in the plant nursery were transplanted to moderate saline alkaline soil. The survival rate retained >50% even 2years after the transplanting, whereas the survival rate for the past several years by conventional transplanting had showedapproximately 20%.
Key Words: Humic acid, Improvement, P. R. China, Saline-alkali soil, Sulfur

1. Introduction
Saline-alkali soil mainly spreading in the northeast China isestimated at least 346,000 km2 (Wang et al., 2007). The soil
has a problem on low crop production caused from highelectric conductivity and low water potential by salinity andmicronutrient unavailability by high pH. Calcium compoundsuch as gypsum (US Salinity Laboratory Staff, 1954), flue gas
desulfurization gypsum (Sakai et al., 2004; Chun et al., 2001),
or sulfur compound such as elemental sulfur (El-Tarabily, et al.,2006) and mixture of elemental sulfur and humic acid (JapanInternational Cooperation Agency, 2003) were proposed as
chemicals to ameliorate saline-alkali soil. Mixture ofelemental sulfur and humic acid named as Desalination of Soil
(referred hereafter to as DS) has been developed mainly inShanxi province and was reported to have positive effect foryield of crop especially corn, which is one of major crops inShanxi province. The local research institute is recently
trying to spread DS to other provinces.
Grape is cultivated on a large scale in the northern ruralarea of Lanzhou in Gansu province. They control the harvest
season to early January by sunshade cover reducing sunshine
in the early summer. Because early January is a “niche”

period for fresh fruit supply in domestic food chains, the grapes
are traded with extremely high prices. Thus local grape
farmers afford to pay relatively more expenses for soil addtives
to improve the disadvantageous soil condition than farmers inother areas.
In the present study, the objectives are the following:1) to clarify the distribution of saline-alkali soil around grape
cropping area in Gansu Province2) to clarify the mechanism of how DS which consisted ofsulfur, humic acid, and organic matter worked for soil
improvement and3) to evaluate DS on agricultural production including grape
seedling on saline-alkali soil

2. Materials and Methods
2.1. Soil properties in northern Gansu province
Soil samples were collected from 11 typical farm lands
including grape greenhouse, from Yondeng prefecture,
approximately 70 km northwestern of Lanzhou city to northborder of Lanzhou city (Fig. 1) in March 2009. Surface soil
(0-10cm) were air-dried and passed through 2 mm mesh thieve
before pH (1:2.5 with deionized water) and electricconductivity (EC; 1:5 with deionized water) were determined.

* Corresponding Author: yu_ishikawa@akita-pu.ac.jp
241-438 Shimoshinjo-Nakano, Akita, Akita, 010-0195 Japan1) Faculty of Bioresource Sciences, Akita Prefectural University3) Arid Land Research Center, Tottori University, Japan2) Northwest Normal University, P. R. China

4) Shanghai Jiaotong University, P. R. China

Fig. 1. Location of the survey sites. White circles in the right figure represent the sampling points. No.1 and 9 were utilized as green house, No. 2 – 8 and 10
were crop fields, and No.11 was a bare land.

2.2. Soil chemical and microbial changes in incubation test
2.2.1. Mechanism how DS worked for soil improvement
250 g soil collected from the potting soil in the grape
seedling nursery near No.1 in Figure 1 was filled into a beaker
along the following treatments; without additives (Control),with elemental sulfur (+S), with humic acid (+HA), with DS(+DS) according to standard application rate of DS, i.e. 2.25
tDS ha-1. Sulfur was used as a form of powder with reagent
grade (Kanto Kagaku), and humic acid was extracted fromlocal charcoal treated with nitric acid by a local company.
Content of DS was showed in Table 1 After they wereincubated with water of 60% of field capacity in 30ºC for
approximately 3 months (2009/7/24～10/20), the soils weredried to determine pH and SO42- content.
2.2.2. Microbial changes with DS application
Three of 250 g soils collected from the fresh potting soil in
the grape seedling nursery near No.1 and from wheat crop fieldnear No. 2 in Figure 1 were filled into beaker without DS(-DS) / with DS (+DS) according to standard application rate,i.e. 2.25 tDS ha-1. They were incubated with water of 60% offield capacity in 30ºC for approximately 3 months (2009/7/24～10/20). Soil samples were collected every 2 weeks toanalyze Denaturing Gradient Gel Electrophoresis (DGGE) for

microbial diversity and were collected at the termination of theincubation to determine pH and SO42- content.
2.3. Effect of sulfur-humic acid on agricultural production
including grape growth
Grape seedlings grown with DS from January 2008 weretransplanted into a greenhouse in November 2008 where thetransplanting had rarely succeed because of saline-alkali soil
(pH 8.07, EC 1.02 ds m-1). By counting the living plants
before the transplanting, the previous survival numbers wereestimated. Survival rate was calculated as the number ofsurvival seedlings / total planted seedling × 100(%).

3. Results and Discussion
3.1 Saline-alkali soil in Gansu province
Soil pH and salinity series were shown in Figure 2. Soil
pH ranged from 7.79 to 8.61, whereas soil electric conductivity
ranged 1.25 to 6.27 dS m-1. The sampling point showing theTable 1. Content of mixture of elemental sulfur and humic acid (DS).

Fig. 2. Soil properties in Gansu province. Sample number means thelocation number in Fig. 1.

highest EC, i.e. No. 11 was located the downstream of thelocal river. No significant relationship between geologicallocation and soil pH neither EC were shown. Soil samples
with high pH show the tendency of low EC except No. 11.
Compared with pH of severe alkali soil in Shanxi orHeilongjian Provinces showing more than 10 (JapanInternational Cooperation Agency, 2003, He et al., 2008), thealkalinity on the sites was comparatively moderate because thesamples were collected from present farming area.

Table 2. Soil pH and sulfate content changes after 3 month incubation.

3.2. Soil chemical and microbial changes in incubation test
3.2.1. Mechanism of how DS worked for soil improvement
Soil pH and sulfate content after 3 months of incubation
with different soil additives was shown in Figure 3. Soil pHwith sulfur and DS show the tendency to drop slightly larger
than control; the difference was approximately 0.1. On theother hand, sulfate content in the two additives, sulfur and DS,
especially with DS remarkably increased than control. The
results suggested that sulfur oxidization process was partly
accompanied with sulfate production in the soil condition.
The reason why the pH reduction was limited compared withthe trial conducted in Shanxi Province (Japan International
Cooperation Agency, 2003) would be that the soil pH wasoriginally low and would be that the number of native sulfur
oxidization bacteria was small.
Changes of soil pH and sulfate content were shown inTable 2. The higher the pH was originally, the bigger thereduction of pH after the incubation was. The result that
sulfate increase was not exactly related with soil pH decreasesuggests sulfate production partly contributes pH reduction.
Effect of DS application on saline-alkali soil varied with soil
samples because pH buffering ability can be different betweenthe soils.
Figures 4 and 5 showed DGGE analyses at the beginningof the incubation and 2 week incubation, respectively. At firstthe band pattern differed among the soil, whereas theIn ‘+/-DS’ column, ‘-DS’ and ‘+DS’ means added without / with DS

SO42-Soil+/-DS

pH

A-DS

7.75

4089

+DS

7.71

9692

BC(cmol･kg-1)

-DS

7.97

377+DS

7.83

4543

-DS

8.48

148+DS

8.094772

respectively.

Fig. 4. DGGE analysis in each soil at the beginning of incubation(2009/07/24). Lane 1 is a marker. Lane 2-7 represents eachsample. Different alphabets mean kinds of soil and ‘-‘/‘+’ mean
without/with DS respectively.

Fig. 5. DGGE analysis in each soil 2 week after incubation started(2009/08/08). Lane 1 is a marker. Lane 2-7 represents eachsample. Different alphabets mean kinds of soil and ‘-‘/‘+’ mean
without/with DS respectively. Angled triangles point out new
bands or significant strong bands compared with counter lane.
Fig. 3. Soil pH and sulfate content changes with additives after 3
month incubation. In Treatment ‘Control’ means withoutadditive, and ‘+S’, ‘+HA’, and ‘+DS’ means added with sulfur,
humic acid , and DS respectively.

presence of DS made no effect on the band pattern in Figure 4.
Two weeks after, distribution of bands with DS was apparently
changed from those without DS. Bacterial communities

community at the early stage of the incubation. DS
application can stimulate microbial community in the grape
cultivation. Unfortunately, harvest in the season was failed byheavy tail. We need to investigate effect of DS on yield andquality of grape in the area for further study.

ReferencesFig. 6. Time course of survival rate (=survived number of seedlings /transplanted number of seedlings) of grape seedlings.

concerning nutrient or sulfur metabolism in DS were activated
to explode within 2 weeks.
3.3. Effect of sulfur-humic acid on agricultural production
including grape growth
Conventional transplanting without any saline-alkali soil
amendments had succeeded in only 17% of survival rate (Fig.
6). The survival rate agreed with farmer’s interview (theestimated survival rate was 25%). The seedlings with DS in
the nursery were able to keep in growth and the survival rate
showed as high as 80% even after 9 months and gradually
dropped up to 50% for 2 years.
The local grapes can be harvested from 2-3 years after thetransplanting into a greenhouse. By the farmer’s observation,
10% of the grape trees with DS produced fruit by contrast
those in the conventional planting had no fruit. They could
harvest the first grapes in the early January, 2010 without
heavy hail in the November, 2010.

4. Conclusion
The survey of saline-alkali soil northwestern of Lanzhou
indicated cropping area in Gansu Province had moderatesaline-alkali soil. Soil incubation did not show apparent
effect on pH reduction with content of DS, because ofmoderate pH and its poor microbial population, on the other
hand DGGE analysis suggested apparent change of microbial

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