Natural Resources, 2012, 3, 88-94
http://dx.doi.org/10.4236/nr.2012.33013 Published Online September 2012 (http://www.SciRP.org/journal/nr)
Effects of Crop Stubble on Physicochemical Properties of
Continuous Cropping Soil and Cucumber Yield and
Quality
Yuyan Wang1,2, Zhongwei Wang1*, Guichun Yang1, Li Wang1, Yi Zheng1
1Institute of Economic Botany, Jilin Academy of Agricultural Sciences, Gongzhuling, China; 2Eco-Agriculture Research Center,
Binzhou Vocational College, Binzhou, China.
Received May 29th, 2012; revised August 3rd, 2012; accepted August 14th, 2012
ABSTRACT
By a pot experiment, two kinds of crop stubble (wheat, soybean) were added into continuous cropping soil of cucumber
according to different quantity (0.5%, 1% and 2%), the effects of different kinds of stubble and quantity on the con-
tinuous cropping soil and growth of cucumber were investigated. The results showed that two kinds of crop stubble sig-
nificantly decreased soil bulk density, and increased total porosity of soil. Each of all treatments significantly decreased
the accumulation of salinity in soil within the entire growth period of cucumber. 2% wheat stubble treatment had the
biggest drop in soil EC in th e later period of cucumber growth. Soybean stubble treatment had the lesser effect on soil
EC. Wheat and soybean stubble promoted the growth of cucumber, increas ed the yield of cucu mber, and improv ed the
quality of cucumber. 2% of wheat stubble treatment had a bigg est increase in cucu mber yield , which increased th e yield
by 34.23% compared with the control.
Keywords: Wheat; Soybean; Stubble; Con tinuou s Cropping Cucumber; Sick Soil; Yield and Quality; Physicochemical
Properties
1. Introduction
Along with the continuous development of protected
vegetables, it is increasingly common that the same kind
of vegetable was continuously grown in the same piece
of land, so, the soil diseases in protected vegetables cul-
tivation becomes more and more severe [1]. A number of
vegetables in protected cultivation such as cucumber,
tomato, eggplants, pepper and so on have frequently suf-
fered continuous cropping obstacles, the continuous crop-
ping obstacle often caused these plants weak growth, in-
ferior fruit quality and special soil diseases [2,3]. The
cucumber is one of the main types to be cultivated in
protected vegetables, and it is even extremely intolerant
to continuous cropping. Therefore, the continuous crop-
ping obstacles of cucumber is more severe, which has
already become one of the major factors for restricting
the yield and quality of protected cucumber. Thus, it is
imminent to solve the problem of continuous cropping
obstacle of protected cucumber.
In order to explore the effective ways and measures to
overcome or reduce continuous cropping obstacle of pro-
tected vegetables, agricultural experts had contributed a
lot of research work. Currently there are three kinds of
remediation technologies including physical, chemical
and bioremediation to continuous cropping soils [4]. How-
ever, these technologies all have certain limitations.
Some studies showed that organic materials could im-
prove the physicochemical properties of continuous crop-
ping soil, increase the diversity of microbial community
structure in soil, inhibit the reproduction of pathogenic
microorganisms in soil, and reduce the accumulation of
toxic substances in soil [5]. For example, straw returning
had very good effects for improving and cultivating the
sick soil [6], the application of straw mixed with bio-
preparate could improve the continuous cropping soils in
greenhouse, even could promote the growth and devel-
opment of vegetable [7]. In order to discover more ef-
fective ways and measures for overcoming or reducing
continuous cropping obstacle of protected vegetables, we
placed two kinds of crushed crop stubble (wheat and
soybean) into the soil of continuous cropping cucumber
for study. Currently, the studies of effect of wheat, soy-
bean stubble on the continuous cropping obstacle of cu-
cumber have not been reported. At the same time, the
straw and stubble are waste in farmland, if which are
*Corresponding a uthor.

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality 89
used for improving the continuous cropping soil, the re-
sources will be saved, and environmental pollution will
be reduced. Therefore, this study has great applicated
value and theoretical significance.
In addition, because the allelopathy is ubiquitous in
crops, and it has significant effect on seed germination
and crop growth [8], so the types of stubble to be used
for improving continuous cropping soil of cucumber
should be strictly selected. Meanwhile, the consumption
of stubble adding, the methods of stubble adding and
other issues all need to be further studied. To this end, in
this study, we selected two kinds of crops stubble (wheat
and soybean) and placed them into continuous cropping
soils of cucumber in greenhouse to study the effect of the
crops stubble on the continuous cropping soils and cu-
cumber growth, so that we can provide scientific basis
and technical methods for solving the problem of con-
tinuous cropping obstacles in protected vegetables.
2. Materials and Methods
2.1. Experimental Materials
Wheat (Triticum aeslivum L.) variety: Kefeng No. 6,
soybean (Glycine max) variety: North 86-4, cucumber
(Cucumis sativus L.) variety: Tianjin Green No. 3.
The tested stubble: Wheat and soybean stubble were
obtained from the residues of previous crops harvested,
including the roots. When the crops stubble was collected,
firstly, the stubble was dug from soil, and then cleaned,
dried, and crushed by the grinder [8]. The physicochemi-
cal properties of the crops stubble were as shown in the
following table (Table 1).
The tested soil: the sampled soil was taken from con-
tinuous cropping soil of cucumber in greenhouse, the
basic physicochemical properties of the sampled soil
prior the experiment were as shown in the following ta-
ble (Table 2).
2.2. Pot Study
Here, studies were done in p ot s in March to August, 2009.
The diameter of pot was 30 cm, 22 cm high, loading 8
kg of soil per pot. First, the soil of continuous cropping
cucumber was sieved through 6 mm sieve to remove lar-
ger clods and the other plant residues etc. Second, the
sieved soils and crushed stubble were uniformly mixed
together according to the different weight ratio (Table 3).
Third, we placed the mixed so ils into pots (8 kg per 30 ×
22 cm pot). Then, these pots were adequately watered,
covered by plastic film to decompose for 21 days in solar
greenhouse. To release some of harmful gases, the plastic
film had been removed for a week when cucumber seed-
lings were planted. The pots were placed on ground in
solar greenhouse as 60 × 30 cm, and 5 g diammonium
phosphate was put into per pot, cucumber seedlings were
planted after three days. The pots without stubble were
used as the controls (CK).
The experiment included a total of 7 treatments (2 kinds
of stubble × 3 kinds of dosage + 1 control). And these
treatments were repeated 3 times, we used 30 pots for
each treatment, making a total of 630 pots.
Table 1. Physicochemical properties of the te ste d stubble.
Tested
stubble Total carbon (mg· g–1) Total nitrogen (mg·g–1) Total phosphorus (mg·g–1) Total potassium (mg·g–1) C/N
Wheat 328.57 7.38 1.71 9.52 83.63
Soybean 284.67 9.36 1.35 3.54 49.27
Table 2. Physicochemical properties of the tested soils.
Total
nitrogen
(g·kg–1)
Alkalihydrolysible
N
(mg·kg–1)
Total
hosphorus
(g·kg–1)
Quick acting P
(g·kg–1)
Total
potassium
(g·kg–1)
Quick acting
K
(g·kg–1)
Organic
matte
(%) pH EC
(ms·cm–1)
2.67 0.292 1.63 0.269 1.16 0.327 1.56 7.661.61
Table 3. The Symbols used for different stubble and quantity.
Stubble Wheat Soybean Control
Adding quantity 0.5% 1% 2% 0.5% 1% 2% 0
Symbol A1 A2 A3 B1 B2 B3 CK

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality
90
2.3. Sampling and Determination
Sampling: We sampled one time per 20 days after the
cucumber seedlings planting, making a total of 3 times.
We randomly selected 3 pots to collect rhizosphere soil
each time, the topsoil in the vicinity of the cucumber
plants was removed before collecting rhizosphere soil.
The soil samples of 3 replications were collected respec-
tively, then mixed, sieved through 2 mm sieve. The soil
samples were air-dried for storage, which were used for
determining physicochemical indicators of the continu-
ous cropping soil and soil enzyme activity.
Soil indicators: Soil pH was determined using the
PHS-2F digital pH meter, Soil EC by using DDS-11A
conductivity, the soil bulk density by using cutting ring,
total porosity of soil was calculated by soil bulk density
(r) and soil proportion (d), the formula is as follows:

11 100%prd 


.
The soil density was replaced by the mean value of gen-
eral soil, taking 2.65 (g/cm3). The soil moisture was de-
termined using drying weight method, the formula is as
follows:
Soil moisture (%) =



12 2100% 9,10WW WW .
Cucumber yield: Five plants were chosen arbitrarily in
each treatment, and were marked. We recorded yield of
each plant singly, took their average, and then converted
it into the yield of per hectare (hm2).
Cucumber quality: So luble solids were determined us-
ing hand-held sugar meter (Made in Japan), Vc content
by using 2,6-dichlorophenol indophenol titration. Taste
was evaluated by using sensory identification method.
3. Results
3.1. Physicochemical Properties of Soil
3.1.1. Bulk Density and Porosity
Wheat and soybean stubble decreased the bulk density of
soil, and increased soil porosity (Table 4). All wheat
stubble treatments decreased significantly bulk density of
soil, moreover, the bulk density constantly decreased as
the increase of wheat stubble quantity. A2 and A3 had
the larger reduction, but there was no significant differ-
ence between the A2 and A3. Soybean stubble had also
similar effect, but the effect of soybean stubble was
smaller than that of wheat stubble. This shows that two
kinds of crop stubble help to decrease bulk density of soil,
and increase the soil permeability. However, each of
stubble treatments had contrary result on the porosity of
soil. All treatments increased the porosity of soil, more-
over, the porosity constantly increased as the increase of
stubble quantity. 2% wheat stubble had a greatest effect
on the porosity of soil, in creasing by 24.4% than the co n-
trol, and followed by 2% soybean stubble, increasing by
18.96%.
3.1.2. Soi l Moisture
Two kinds of crop stubble had certain effect on soil pH,
but the effect was different in different growth periods
(Figure 1). In the pre-stage of cucumber growth, two
kinds of stubble increased the moisture of soil, wheat
stubble had greater effect on the moisture of soil com-
pared with soybean stubble. The greatest effect was ob-
served in 2% wheat stubble treatment, which increased
the moisture by 26.37% compared with control. Soybean
stubble treatments had similar effects, but these effects
were smaller, in particular, 0.5% soybean stubble had a
minimum effect, which had no difference compared with
the control.
In the medium term, wheat stubble treatment increased
largely the moisture of soil, 2% of wheat stubble had
greatest affect on the moisture, which was significantly
higher than other treatments and control, increased by
34.35% than control. Soybean stubble treatment had also
similar effects, 2% of soybean stubble treatment had
greatest affect on the moisture.
In the later period, all treatments increased the soil
moisture too, but these treatments had lesser increase in
soil moisture.
Table 4. Effect of different treatments on bulk density and porosity of soil.
Treatments Bulk density (g·cm–3) Total porosity (%)
A1 1.21 ± 0.08bc 54.34 ± 6.16c
A2 1.02 ± 0.08d 58.51 ± 8.02b
A3 1.01 ± 0.06d 61.89 ± 6.33a
B1 1.26 ± 0.05b 52.45 ± 4.61cd
B2 1.16 ± 0.07c 56.23 ± 7.12bc
B3 1.12 ± 0.03c 57.74 ± 3.13b
CK 1.41 ± 0.08a 46.79 ± 5.18e
Note: Values are means ± standard deviation. Significant differences (P < 0.05 using Duncan’s multiple range test) among
treatments in the same column are indicated by different letters, the same as below.

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality 91
ded
b
ab b
a
aa
efe
bc dc
b
cc
eecd
0
5
10
15
20
25
20 40 60
Days after planting
S oil mo istu re（%）
A1
A2
A3
B1
B2
B3
CK
Figure 1. Effect of different treatments on moisture of soil.
3.1.3. Soil pH
Two kinds of stubble had certain effect on soil pH, but
the effect was relatively smaller (Table 5). In the pre-
stage and mid of growth, most of the stubble treatments
decreased soil pH, only the 2% wheat stubble (A3) in-
creased it. 2% wheat stubble treatment had the greatest
increase in the soil pH, but there was significant differ-
ence between it and control. Other treatments had no
significant di ff erence too.
In the later stage of growth, all stubble treatments de-
creased soil pH but only 2% wheat stubble treatment
increased it. 2% wheat stubble treatment was signifi-
cantly higher than control, while other treatments had on
significant difference compared with control. The maxi-
mum decrease was observed in the 1% soybean stubble
treatment, but it had on significant difference compared
with control.
3.1.4. Soil EC
Two kinds of stubble had relatively larger effect on soil
EC (Table 6). In the pre-stage of cucumber growth, all
wheat stubble treatments significantly decreased soil EC,
a maximum decrease was observed in 1% wheat stubble
treatment, and followed by 0.5% wheat stubble treatment.
Soybean stubble also decreased soil EC, the soil EC val-
ues of all soybean stubble treatments were significantly
lower than the control, 0.5% and 1% of soybean stubble
had greater decrease in soil EC. In the mid-and late,
whether wheat stubble or soybean stubble all showed the
similar laws in soil EC.
3.2. Cucumber Yield
Two kinds of stubble increased yield of cucumber (Fig-
ure 2). All treatments of wheat stubble markedly in-
creased yield of cucumber, the highest yield was ob-
served in 2% wheat stubble treatment, which increased
the yield by 34.23% compared with control. Soybean
stubble increased yield of cucumber too, but soybean
stubble treatment had the smaller increase than wheat
stubble treatment. The higher yield was observed in 1%
soybean stubble treatment, which increased the yield by
16.01% compared with control.
Table 5. Effect of different treatments on soil pH after
planting.
Treatments20 days 40 days 60 days
A1 7.35 ± 0.04ab 7.35 ± 0.08ab 7.33 ± 0.16bc
A2 7.34 ± 0.14ab 7.47 ± 0.17ab 7.27 ± 0.14bc
A3 7.77 ± 0.16a 7.73 ± 0.06a 7.66 ± 0.05a
B1 7.62 ± 0.06a 7.38 ± 0.03ab 7.34 ± 0.05bc
B2 7.41 ± 0.12ab 7.35 ± 0.05ab 7.26 ± 0.03bc
B3 7.21 ± 0.09b 7.30 ± 0.06ab 7.28 ± 0.08bc
CK 7.61 ± 0.08a 7.65 ± 0.11a 7.49 ± 0.11b
Table 6. Effect of different treatments on soil EC after
planting (ms/cm).
Treatments20 days 40 days 60 days
A1 0.79 ± 0.04f 1.07 ± 0.06e 0.82 ± 0.03f
A2 0.73 ± 0.07cd 1.04 ± 0.07e 0.88 ± 0.06ef
A3 0.97 ± 0.02e 1.01 ± 0.04e 0.80 ± 0.06f
B1 1.14 ± 0.09c 1.13 ± 0.06d 0.93 ± 0.08e
B2 1.16 ± 0.07c 1.16 ± 0.05d 1.38 ± 0.03b
B3 1.24 ± 0. 0 8b 1.37 ± 0.09c 1.25 ± 0.04c
CK 1.62 ± 0.03a 1.72 ± 0.01a 1.66 ± 0.05a
ede
b
fg
c
f
a
0
20000
40000
60000
80000
100000
A1 A2 A3 B1 B2 B3 CK
treatments
Yield（kg. hm-2）
Yield (kg·hm
-2
)
Figure 2. Effect of different treatments on the yield of cu-
cumber.

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality
92
3.3. Cucumber Quality
As can be seen from Table 7, wheat stubble significantly
improved cucumber quality. First, wheat stubble in-
creased the content of dry matter, moreover, the content
of dry matter gradually increased as the increase of wheat
stubble quantity. Second, wheat stubble increased the
content of vitamin C and soluble solids in fruits, but
0.5% wheat stubble treatment had no difference com-
pared with the control. Third, wheat stubble decreased
the incidence of deformed fruits. The greatest decrease
was observed in 2% wheat stubble treatment, and fol-
lowed by 1% wheat stu bbl e t reat ment.
Soybean stubble had certain effect in improving fruit
quality too. 0.5% and 1% of soybean stubble treatments
increased the content of dry matter, while an opposite
result was observed in 2% of treatment. Soybean stubble
had no obvious regularity on the content of vitamin C
and soluble solids in fruits, which was sometimes as-
cending and sometimes descending. 0.5% of soybean
stubble treatment significantly increased the content of
vitamin C in fruits, but it h ad a little effect on the soluble
solids. 2% of soybean stubble treatment decreased the
incidence of deformed fruits, which was significantly
lower than control.
4. Conclusions
Many studies showed that organic materials decreased
soil bulk density, increased total porosity, increased soil
aggregate structur e, and impro v ed soil permeab ility when
they were added into soil [9,10]. At the same time, or-
ganic materials could increase soil pH, and lower soil EC,
even that they could improve the physicochemical prop-
erties [11,12].
In this test, whether wheat stubble or soybean stubble
obviously decreased soil EC, especially in the later pe-
riod, the decrease of soil EC was greater. Each of all
treatments significantly decreased the salinity accumula-
tion in soil within the entire growth period of cucumber,
a maximum decrease of the EC was observed in 2%
wheat stubble treatment, while effect of two kinds of
stubble on soil pH was not obvious. This may be related
to the microbial metabolism, because the stubble can
provide more nutrients for the microorganisms in soil,
and promote the activity of microorganisms. Thus, wheat
or soybean stubble can reduce continuous cropping ob-
stacle in greenhouse soil. For example, when two kinds
of stubble are added into the continuous cropping soil,
many of the problems such as soil compaction, staliniza-
tion, poor permeability and poor water holding capacity,
even some soil sickness will be solved . Therefore, wheat
stubble or soybean stubble has a positive effect in pro-
moting cucumber growth and improving sick soil.
Soil moisture is an important indicator related to soil
microorganism activity and crop growth, which directly
affects the growth and yied of crops. According to re-
search report [13,14], straw returning en hanced the abili-
ties for soil to retain water and nutrients, increase capac-
ity of holding water, and improve the effectiveness of
natural precipitation. Wang [15] (2000) studied the ef-
fects of straw for different processing methods on soil
moisture, the results showed that straw returning im-
proved soil moisture condition s, increased the cap acity o f
water storage and water retention in soil.
In this test, the results showed that two kinds of stub-
ble increased soil moisture, while the effect of wheat
stubble on soil moisture was greater than that of soybean
stubble, and 2% of wheat stubble had greatest effect,
which increased soil moisture by 26.37% compared with
control. One of the main reasons is that the density of
wheat stubble is smaller than that of soybean stubble, so
the volume of wheat stubble is relatively larger than that
of soybean stubble. Therefore, wheat stubble treatment
has greater increase on soil total porosity than soybean
stubble, so wheat stubble is more conducive to increase
the soil moisture. In addition, because the density of
Table 7. Effect of different treatments on the quality of cucumber.
Treatment Deformed fruits r ate (%) Dry matter
(%) Vitamin C (mg/100g FW) Soluble solids (%) Taste
A1 9.32 ± 0.13c 3.15 ± 0.08cd 9.85 ± 0.09e 7.6 ± 0.06d Good
A2 6.33 ± 0.08e 3.84 ± 0.06b 12.23 ± 0.13b 9.1 ± 0.09a Excellent
A3 5.57 ± 0.06ef 3.96 ± 0.11ab 13.22 ± 0.15a 8.9 ± 0.06ab Excellent
B1 9.01 ± 0.16c 3.33 ± 0.10c 12.37 ± 0.18b 8.1 ± 0.12b Good
B2 8.33 ± 0.06d 3.37 ± 0.04c 10.58 ± 0 .12d 7.9 ± 0.07b Excell e n t
B3 11.28 ± 0.09 a 2.26 ± 0.06ef 10.59 ± 0.11d 7.5 ± 0.10d Good
CK 9.67 ± 0.11c 2.63 ± 0.07e 9.66 ± 0.07e 7.8 ± 0.11d General

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality 93
wheat stubble is smaller than that of soybean stubble, so
more wheat stubble was floated on the water when wa-
tering, and it was just attached to the soil surface after the
water seeping down, thus wheat stubble treatment can
decrease water evaporation, and relatively increase the
soil moisture. This may be another reason that the wheat
stubble is more conducive to increase the soil moisture.
According to studies, there are three major reasons on
continuous cropping obstacle of cucumber: First, the
nutrients in soil were in imbalance, the physicochemical
properties of soil became worse. Second, the pathogens
in soil proliferated quickly, the ecological environments
of microorganisms were destroyed, and the biological
properties of soil became worse. Third, it is due to the
allelopathy of the root exudates and the stubble decom-
position [5,16,17 ]. It is exactly effective ways and meas-
ures for Mixed intercropping, crop rotation and the de-
velopment and application of soil remediation agents to
solve this problem. According to the investigation, straw
return can promote the growth of crops, increase crop
yields by 5% - 10% [18,19]. According to another report,
organic material also can increase cucumber yields when
it was added into soil in the greenhouse [4,20]. In our
experiment, wheat and soybean stubble promoted the
growth of cucumber, increased yield of cucumber. Among,
1% and 2% of wheat stubble markedly increased yield of
cucumber, the highest increase of yield was observed in
2% wheat stubble treatment, which increased the yield by
34.23% compared with control. Thus, two kinds of crop
stubble can coordinate the water, gas, heat, nutrient and
other condition s in soil, impro ve the physicoche mical pro-
perties of soil. So, this helps to establish a good founda-
tion for cucumber growth and yield increase. In our ex-
periment, the wheat and soybean stubble increased soil
moisture, this may be one of the important reasons wh ich
caused the increase of cucumber growth and yield.
5. Conclusion
Wheat and soybean stubble all obviously decreased the
soil EC, while the effect of two kinds of stubble on soil
pH was not obvious. Two kinds of stubble increased soil
moisture and porosity, in which th e effect of wheat stub-
ble was more remarkable than that of soybean stubble. At
the same time, wheat and soybean stubble promoted the
growth of cucumber, increased the yield of cucumber,
and improved the quality of cucumber. This shows that
wheat and soybean stubble can improve the physico-
chemical properties in continuous cropping soil, and re-
duce continuous cropping obstacles of cucumber.
6. Acknowledgements
This project was financially supported by Introducing
Innovation Talent Fund of Jilin Province. Here, I express
my heartfelt thanks for them.
REFERENCES
[1] Z. Z. Li, Y. Wu and Y. J. Yang, “Effects of Soil Con-
ditioners on Cucumber Growth and Soil Conditions in
Greenhouse,” Acta Agriculture Shanghai, Vol. 27, No. 2,
2011, pp. 87-91.
[2] J. Liu, Y. Q. Tian and L. H. Gao, “Effects of Summer
Catch Crop and Straw Returning on Cucumber Soil Nu-
trients and Microorganism in Solar Energy Green-
house,” China Vegetables, Vol. 6, No. 8, 2011, pp. 12-16.
[3] H. Q. Wu, L. L. Dong and Q. Wang, “Effects of Garlicon
Cucumber Growth and Soil Biology in Solar Green-
house,” Journal of China Agricultural University, Vol. 16,
No. 3, 2011, pp. 95-99.
[4] M. Yang, L. J. Yang and Q. Chang, “Effect of Different
Straw Reapplication on Yields of Cucumber and Soil Fer-
tility,” Northern Horticulture, Vol. 6, 2011, pp. 46- 48.
[5] Z. Q. Gao and S. X. Zhang, “Continuous Cropping Ob-
stacle and Rhizospheric Microecology I. Root Exudates
and Their Ecological Effects,” Chinese Journal of Ap-
plied Ecol ogy, Vol. 9, No. 5, 1998, pp. 549-554.
[6] Z. J. Wu, H. J. Zhang and G. S. Xu, “Effect of Returning
Corn Straw into Soil on Soil Fertility,” Chinese Journal
of Ap plied Ecology, Vol. 13, No. 5, 2002, pp. 539-542.
[7] Z. D. Yu and S. Y. Song, “Effects of Straw Mixed with
Biopreparate on Improvement of Soil in Greenhouse,”
Chinese Society of Agricultural Engine, Vol. 19, No. 1,
2003, pp. 177-179.
[8] Y. Y. Wang and F. Z. Wu, “Allelopathic Effects of
Wheat, Soybean and Oat Residues on Cucumber and
Fusarium oxysporum f. sp. cucumerinum Owen,” Allelo-
pathy Journal, Vol. 25, No. 1, 2010, pp. 107-114.
[9] J. Wu, Z. L. Zhu and J. G. Zheng, “Effect of Straw Re-
turing Covering on Physical and Chemical Properties of
Soil and Crop Yield,” Journal of Southwest Agricultural
University, Vol. 19, No. 2, 2006, pp. 192-195.
[10] L. Zhu, C.-L. Zhang and Q. R. Shen, “The Influence of
Appling Organic Materials in the Continuous Cropping
Soil on the Soil pH and EC Value and Microbe,” Journal
of Anhui Agricultural University, Vol. 28, No. 4, 2001, pp.
350-353.
[11] X. F. Zhou, Y. H. Xie and Y. H. Pei, “Effect of Adding
Straw Powder on the Physical and Chemical Properties of
Saline Alkali Soil,” Hubei Agricultural Sciences, Vol. 50,
No. 23, 2011, pp. 4806-4808.
[12] E. Ouedraogo, A. Mando and N. P. Zombre, “Use of
Compost to Improve Soil Properties and Crop Produc-
tivity under Low Input Agricultural System in West Afri-
ca,” Agriculture Ecosystems and Environment, Vol. 84,
No. 3, 2001, pp. 259-266.
doi:10.1016/S0167-8809(00)00246-2
[13] Z. X. Zhu and T. X. Liu, “Research Progress of Ecologi-
cal Effect of Straw Returning,” Anhui Agricultural Sci-
ences, Vol. 35, No. 23, 2007, pp. 7221-7223.
[14] Q. H. Zhan, X. P. Zhang and C. L. Yuan, “Study on the

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality
94
Effect of Straw Returning and It’s Mechanism in Im-
proving Shajiang Black Soil,” Journal of Anhui Agricul-
tural University, Vol. 29, No. 1, 2002, pp. 53-59 .
[15] A. L. Wang, W. S. Gao and J. Y. Huang, “Study on the
Ecological Effect of Returning into Soil with Different
Methods,” Chinese Journal of Agricultural Resources and
Regional Planning, Vol. 21, No. 2, 2000, pp. 41-45.
[16] X. He, W. S. Wei and R. G. Sun, “Effect of Straw-Ben-
tonite-PAM Improved Material on Saturated Water Con-
tent in Sandy Soil,” Chinese Agricultural Science Bulletin,
Vol. 28, No. 9, 2012, pp. 75-78.
[17] X. Y. Ma and H. M. Wang, “Technology of Crop Stubble
Returning to Fields,” Jilin Agricultury, No. 9, 2010, pp.
56-58.
[18] P. Mu, E. H. Zhang and H. N. Wang, “Effects of Con-
tinuous Straw Return to Soil on Maize Growth and Soil
Chemical and Physical Characteristics,” Chinese Journal
of Eco-Agriculture, Vol. 20, No. 3, 2012, pp. 291-296.
doi:10.3724/SP.J.1011.2012.00291
[19] R. S. Jessop and L. W. Stewart, “Effects of Crop Resi-
dues, Soil Type and Temperature on Emergence and
Early Growth of Wheat,” Plant and Soil, No. 74, No. 1,
1983, pp. 101-109. doi:10.1007/BF02178745
[20] Z. P. Wang, J. R. Yang and C. S. Hu, “The Ways of Effi-
cient Use and Technical Measures of Straw Resources in
Taihang Mountain Plain,” Resources Science, Vol. 23, No.
5, 2001, pp. 67-72.