Effects of In-Furrow Planting Irrigation Method on Soil Salinity Distribution and Water Productivity of Winter Wheat

Full text

1
Effects of In-Furrow Planting/Irrigation Method on Soil Salinity Distribution and Water
Productivity of Winter Wheat
A. Reshadsedghi
1
*, A. Nasseri1, Kh. Mohammadi Ghermezgoli
2
Abstract
Shortage of irrigation water and soil/water salinity are two major constraints that influence crops
production in arid and semi-arid regions. This study was conducted to investigate the effects of
in-furrow planting with furrow irrigation method on soil salinity distribution and water
productivity of winter wheat. Experiments were carried out in a field located at east of Urmia
Lake with a loamy soil texture and salinity (EC) of 12 dSm-1. Soil ridges with 10 cm height were
constructed by a special grain drill which plants wheat seeds into furrows. The experimental
treatments were related to planting and irrigation methods included (i) planting on a smooth soil
and conventional flood irrigation; (ii) planting into the furrows with 60 cm width and furrow
irrigation; (iii) planting into the furrows with 100 cm width and furrow irrigation. According to
the results, reducing the width of the furrow from 100 to 60 cm resulted in better soil leaching
from inside the furrows to the ridges and reducing irrigation water consumption. In terms of crop
yield, there was no significant difference between treatments. However, due to less water
consumption, the water productivity of planting in 60 cm furrows, was significantly higher than
other treatments. Therefore, in semi-arid areas with saline soils, planting within the narrow
furrows and furrow irrigation is preferable.
Keywords: In-furrow planting, Furrow irrigation, Soil salinity, Water productivity, Wheat.
Introduction
Salinity is a major problem affecting crop production over the world. So about 20% of cultivated
land and 33% of irrigated farms were salt-affected and degraded (Machado et al., 2017). Most of
Iran regions have arid and semi-arid climate with a large of areas are covered with sediments of
salts and gypsum. In northwestern regions of Iran, on the banks of the Caspian Sea, in the
northwest, a significant amount of Lake Urmia basin, as well as large areas of central Iran, salty
and sodic soils are dominant. Saline soils and waters are among the agricultural resources that can
be used for cultivation by using full knowledge of problem and proper management.
Modifying water management through appropriate irrigation practices can often lead to increase
crop yields under saline soil conditions (Abrol et al., 1988; Qadir and Oster, 2004). When suitable
agronomic management practices are adopted, the saline soils can also give significantly better
yields. Some of the methods that can be adopted are classified as: (i) Irrigation management
practices, (ii) leaching out of salts, and (iii) drainage systems (Sree Ramulu, 1998). Most plants
require a continuous supply of readily available moisture to grow normally and produce high
yields. After an irrigation event the soil moisture content upraise the highest and salt concentration
or the osmotic pressure of the soil solution is minimal. As the soil progressively dries out due to
1
Agricultural Engineering Research Department, East Azarbaijan Agricultural and Natural Resources Research and
Education Center, AREEO, Tabriz, Iran. *Corresponding author email: a.reshadsedghi@areeo.ac.ir
2
Bio systems Engineering Department, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.

2
evapotranspiration losses, the concentration of salts in the soil solution and therefore its osmotic
pressure increases making the soil water increasingly difficult to be absorbed by the plants. If the
saline soils are irrigated infrequently, plants would be subjected to very high soil moisture stresses
with consequent yield losses.
Irrigation method can play an important role in controlling salts in the root zone. Considerable
important factor of a soil is relation of growth of plants with the location of salts in relation to root
or seed placement. Irrigation practices can often modified to obtain a more favorable salt distribution
in relation to seed location or growing roots. It is well known that salts tend to accumulate in the
ridges when using furrow type irrigation. The direction of movement of applied water and dissolved
salts (arrows) is shown in Figure 1.
Figure 1: Direction of salt flow and salt accumulation in furrow irrigation (Abrol et al., 1988).
With each irrigation, salts leach out of the soil under the furrows and concentrate on the ridges (Abrol
et al., 1988). Where soil and farming practices permit, furrow planting may help in obtaining better
stands and crop yields under saline conditions (Abrol et al., 1988; Yarami and Sepaskhah, 2015). A
mathematical model for simulating soil water and salt transfer under mulched furrow irrigation with
saline water was presented by Chen et al. (2015). The results demonstrated that during the irrigation
interval (192 h and 384 h after the irrigation), more water was maintained below the top of the ridge
due to a considerable reduction of evaporation under mulched furrow irrigation. Soil salt mainly
comes from saline water irrigation and the soil salt below the top of the ridge mainly increased at the
redistribution phase (17 h). In semi-arid regions, switching sowing position from ridge to furrow
could increase corn yield, directly, by improving soil moisture early in the growing season and,
indirectly, by stimulating the growth of resource-capturing organs (e.g., leaves and roots) (Jin et al.,
2010). The pitting and furrow planting methods were the most appropriate methods for alfalfa
planting in highly saline soils (Afsharmanesh and Aien, 2014). Deficit irrigation and salinity
decreased yield and dry matter of rapeseed and in-furrow planting resulted in higher seed yield and
dry matter compared to on-ridge planting (Shabani et al., 2013). According to Dong et al. (2010),

3
furrow-bed seeding induced unequal distribution of salts in the surface soil. Under furrow planting,
soil salinity was much higher but soil osmotic potential was much lower on the ridge part than the
furrows. When irrigation water is applied to the furrows on every side of the bed, it allows salts to
leach down from the furrows (Bakker et al., 2010). But the water evaporation during the drying
periods results in salt accumulation on the tops and side slopes of the raised beds (Richards, 1954).
Such salt movement to the center of the bed may damage (young) plants seeded there (Brady and
Well, 2008). According to Meiri and Plaut (1985), Cardon et al. (2010) and Devkota et al. (2015),
with the permanent skip furrow irrigation (PSFI) method in which one of the two neighboring
furrows is kept dry, salts are leached from the top of the raised bed and ‘pushed’ across the bed
from the irrigated side of the furrow, where plants are located, to the dry side without plants. This
management of root zone salinity improves emergence, stand establishment and finally crop yields
in saline fields. This study was conducted with the objective of comparing three irrigation methods
(flood irrigation and furrow irrigation with different furrow width) and investigating the effect of
furrow width on soil salinity distribution.
Materials and Methods
Study area and site description
This study was conducted to compare three irrigation methods (flood irrigation and furrow
irrigation with different furrow width) and investigate the effect of furrow width on soil salinity
distribution. Experiments were carried out in a field located at 37°46' N and 45° 86'E, near Lake
Urmia with loamy soil texture. The average soil salinity (EC) in soil top 30 cm was 12 dSm-1.
Characteristics of soil and irrigation water are shown in Table 1 and 2 respectively.
Table 1: Soil physical and chemical properties.
Depth
(cm)
EC
(dSm-1)
pH of paste
T.N.V.
%
O.C.
%
P(ava.)
p.p.m.
K(ava.)
p.p.m.
Clay%
Silt%
Sand
%
0-30
12
7.6
15
2.18
100
411
17
31
52
Table 2: Characteristics of irrigation water.
CO22-
HCO3-
Cl -
SO42-
total
Anions
Ca2++Mg2+
Na+
total
Cations
S.A.R
EC
(μS/cm)
pH
SSP
0
11.8
67.5
5.2
84.5
66
25
91
4.4
7420
6.9
27.5
Study set up and experimental design
The irrigation methods included (i) conventional flood irrigation with no furrow (NOF); (ii) furrow
irrigation with 60 cm furrow width (5F); (iii) furrow irrigation with 100cm furrow width (3F). Soil
ridges with 10 cm height were constructed by a special grain drill which plants seeds into furrows.
The 20-Row drill planter working width was 300 cm, thus to create furrows of the desired width,
5 furrowers with 60 cm width and 3 furrowers with 100 cm width were used on planter (Fig. 2 and
3).Four irrigation applied in each treatment plots at different stages of wheat plant growth (25 Oct.
2016 after planting; 7 May 2017 after tillering stage; 21 May flowering stage and 3 June in fill-

4
grain stage). The irrigation mode experiment was laid out in a randomized complete block design
(RCBD) with three irrigation treatments and three replications (9 plots with 1 m spacing). Each
experimental plot with 6 m width and 18 m length was planted by drill planter in two paths.
Soil sampling
Soils were sampled after three irrigation viz. first, second and forth events, when soil drainage was
carried out. Soil samples were obtained each time from three points of each plot (top of the ridges
‘r’, border of the furrows ’b’ and middle of the furrows ‘m’) (Fig. 4). For NOF treatment which
had no furrow, soil samples were taken from three consecutive points at intervals of 30 cm from
the plot width. All samples were taken from 0-30 cm soil depth using a tube auger (5 cm diameter,
22 cm height). The soil samples were air dried and mixed with sufficient distilled water to produce
a saturated paste and then extracted the solution for measurement of electrical conductivity (ECe)in
the irrigation laboratory (Richards, 1954).
Figure 2: The 20-Row drill planter which create five furrows with 60 cm width.
60 cm

5
Figure 3: The 20-Row drill planter which create three furrows with 100 cm width.
Measurement of irrigation water
Irrigation water was applied as surface irrigation methods. Applied water was measured by a WSC
flume. Irrigation times were scheduled by crop phonological stages and all plots were irrigated
four times from cultivating to maturity.
Statistical analysis of soil EC data
Analysis of variance was conducted using split-split-plot experiment based on RCBD with three
factors and three replications (by software SPSS version 19). The main factor was irrigation
methods, the second factor was irrigation events and the third factor was related to the position of
soil sampling in each plot. Each factor was in three levels. The salinity means were separated by
Fisher’s protected LSD (least significant difference (P=0.05)).
100 cm

6
Figure 4: The position of sampling points in ridge and furrow.
Results and Discussion
Soil salinity distribution in ridges and furrows
In irrigation treatment of furrows with 60 cm width (5F), after each irrigation salts were washed out
significantly from middle of furrows toward the ridges and accumulated there, however this does not
apply to irrigation treatment of furrows with 100 cm width (3F). In treatment of the conventional flood
irrigation which had no furrow (NOF), after each irrigation there was no significant difference of
salinity across the plots (Table 3; Figs. 5A. B. C. and 7). This results are accordance with the findings
of Ghane et al. (2009), who reported that with the furrow irrigation method (60 cm furrow width),
salinity at the root zone (shoulder of raised bed) was lower than that in flood irrigation method.
Table 3: Analysis of variance of the treatments effects on soil salinity (EC).
Sources of variations
df
M.S.
F value
Probability
Irrigation methods (Factor A)
2
25.672
2.1317
0.2343ns
Irrigation events (Factor B)
2
65.823
19.5124
0.0002**
A×B
4
11.605
3.44
0.0430*
Sampling locations (Factor C)
2
35.923
7.7864
0.0015**
A×C
4
16.693
3.6183
0.0141*
B×C
4
4.224
0.9155
A×B×C
8
3.835
0.8312
ns, *, **: Difference is not significant, P<0.05, P<0.01
As shown in Fig. 5A, after first irrigation which is the most important stage for seeds
germination, the salinity level on the top 30 cm soil in the middle of furrows with 60 cm width
30 cm
Sampling points
Ridge
Furrow
r
b
m
10 cm

7
Figure 5: The effect of different irrigation methods on soil salinity distribution after each
0
2
4
6
8
10
12
14
16
m b r
Electrical conductivity (dSm-1)
Soil sampling points
After first irrigation (25 Oct. 2016)
60 cm width furrow
100 cm width furrow
no furrow
(A)
0
2
4
6
8
10
m b r
Electrical conductivity (dSm-1)
Soil sampling points
After 2nd irrigation (7 May 2017)
60 cm width furrow
100 cm width furrow
no furrow
(B)
0
2
4
6
8
10
12
14
16
m b r
Electrical conductivity (dSm-1)
Soil sampling points
After 4th irrigation (3 June 2017)
60 cm width furrow
100 cm width furrow
no furrow
(C)

8
irrigation events.
(EC=7.59 dSm-1), was lower than the other treatments. Using this method, after an irrigation
practice, 37% of the initial salinity (EC=12 dSm-1) has decreased. The results of measuring the
electrical conductivity of saturated paste after the second irrigation showed a significant decrease
of soil salinity in all three irrigation methods (Figs 5B. and 6). The reason for this was probably
the penetration of salts in the depths of soil due to seasonal rainfall before the second irrigation
(Wang et al., 2015). Comparison of the effect of three irrigation methods on soil salinity
distribution after fourth irrigation (Fig.5C. and 6) indicates that by increasing furrow width to 100
cm, probably due to an increase in the internal surface of the irrigation furrow, less water flows to
the ridges and the salts concentration in the ridges are reduced. In this stage, the salinity reduction
of the soil in the floor of 60-cm furrows was approximately the same as NOF treatment. It seems
that in furrow irrigation method due to the presence of the ridges, a portion of the soil salts
accumulate in the ridges by the horizontal water flow and part of it is penetrated to the soil depths
by the gravity flow of water.
Figure 6: Reciprocation effects of irrigation methods and sampling location on soil salinity (EC),
(Means with dissimilar letters in each column have significant difference (LSD, P= 5%)).
0
2
4
6
8
10
12
14
furrow middle furrow border top of ridge
5F 7.37 7.807 12.19
3F 10.33 10.32 10.38
NOF 7.854 8.101 9.288
cc
a
ab ab ab
cc
bc
Electrical conductivity (dSm-1)

9
Figure 7: Reciprocation effects of irrigation methods and irrigation events on soil salinity (EC),
(Means with dissimilar letters in each column have significant difference (LSD, P= 5%)).
However, in the flood irrigation method where the soil surface is smooth, soil leaching is carried out
after irrigation or precipitation solely by vertical water flow. The other reason for the similarity of
salinity reduction in both F3 and F5 treatments at the end of the growing season is probably needing
much time to complete the irrigation practice in plots of NOF treatment compared to the furrow
irrigation treatments, therefore, more water is fed to the plots and the soil washed better (Fig. 8).
Water consumption
Total water consumption of irrigation treatments during the growing season, furrow irrigation
treatment with 60 cm furrow width (5F) had less water consumption than the other treatments (Fig. 8).
Ghane et al. (2009) also achieved similar results. As the width of the irrigation furrows decreases, the
space for water expansion inside furrows is limited by the ridges, and this probably leads to an increase
in the velocity of water flow into furrows and reduced the time needed to complete the plots irrigation.
Therefore, in a constant water flow rate, water consumption reduces as irrigation time reduces.
Figure 8: Water consumption of irrigation method treatments.
0
2
4
6
8
10
12
first Irr. 2nd Irr. 4th Irr.
5F 10.01 7.574 9.781
3F 11.16 8.354 11.51
NOF 11.01 6.967 7.263
ab
ab
ab
ab
ab
a
ab
bab
Electrical conductivity (dSm-1)
5264
7032 7508
0
1000
2000
3000
4000
5000
6000
7000
8000
5F 3F NOF
Water consumption (m3ha-1)
Irrigation method treatments

10
Crop yield and Water productivity
The crop yield of treatments 5F, 3F and NOF were 2461, 2501 and 2614 kg/ha respectively,
which had no significant difference statistically. However, due to less water consumption, the
water productivity (the ratio of crop yield to water consumption rate) of treatment 5F (planting
in 60 cm furrows), was significantly (P<0.05) higher than the other treatments (Fig. 9).
Conclusion
Reducing the width of the furrow from 100 to 60 cm resulted in better soil leaching from inside
the furrows to the ridges and reducing irrigation water consumption. Flood irrigation method has
been effective in reducing soil salinity, but due to the high consumption of irrigation water, this
method has less water productivity relation to the in-furrow planting/irrigation method and
therefore is not recommended for arid areas. Consequently, in semi-arid areas with saline soils,
planting within the narrow furrows and furrow irrigation is preferable.
Figure 9: Water productivity of planting/irrigation method treatments
References
Abrol I, Yadav JSP, Massoud F. 1988. Salt-affected soils and their management, Food and
Agriculture Organization of the United Nations, Rome.
Afsharmanesh G, Aien A. 2014. Introducing the new planting methods for cultivation of alfalfa
cultivars in highly saline soils. International Journal of Farming and Allied Sciences. 3(8),
935-939.
Bakker DM, Hamilton GJ, Hetherington R, Spann C. 2010. Salinity dynamics and the potential
for improvement of water logged and saline land in a Mediterranean climate using
permanent raised beds. Soil and Tillage Research. 10 (1), 8–24.
0.46 a
0.34 ab 0.32 b
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
5F 3F No F
Water productivity (kg m-3)
Planting/Irrigation method treatments

11
https://doi.org/10.1016/j.fcr.2010.01.009
Brady NC, Well RR. 2008. The Nature and Properties of Soils. Pearson-Prentice Hall, Upper
Saddle River, NJ, 990.
Cardon GE, Davis JG, Bauder TA, Waskom RM. 2010. Managing Saline Soils,
http://www.ext.colostate.edu/pubs/crops/00503.htm.
Chen LJ, Feng Q, Li FR, Li CS. 2015. Simulation of soil water and salt transfer under mulched
furrow irrigation with saline water. Geoderma. 241-242, 87-96.
https://doi.org/10.1016/j.geoderma.2014.11.007
Devkota M, Gupta RK, Martius C, Lamers JPA, Devkota KP, Sayre KD,Vlek PLG. 2015. Soil
salinity management on raised beds with different furrow irrigation modes in salt-affected
lands. Agricultural Water Management. 152, 243-250.
https://doi.org/10.1016/j.agwat.2015.01.013
Dong H, Kong X, Luo Z, Li W, Xin C. 2010. Unequal salt distribution in the root zone increases
growth and yield of cotton. European Journal of Agronomy. 33(4), 285-292.
https://doi.org/10.1016/j.eja.2010.08.002
Ghane E, Feizi M, Mostafazadeh-Fard B, Landi E. 2009. Water productivity of winter wheat in
different irrigation/planting methods using saline irrigation water. International Journal of
Agriculture and Biology. 11(2), 131-137.
Jin YH, Zou DW, Jiang SC. 2010. Comparison of soil water content and corn yield in furrow and
conventional ridge sown systems in a semiarid region of China. Agricultural Water
Management. 97(2), 326-332.
https://doi.org/10.1016/j.agwat.2009.10.002
Machado RMA, Serralheiro RP. 2017. Soil salinity: Effect on vegetable crop growth.
Management practices to prevent and mitigate soil salinization. Horticulturae, 3(30), 1-13.
http://dx.doi.org/10.3390/horticulturae3020030
Meiri A, Plaut Z. 1985. Crop production and management under saline conditions. Plant Soil 89,
253–271.
Qadir M, Oster JD. 2004. Crop and irrigation management strategies for saline-sodic soils and
waters aimed at environmentally sustainable agriculture. Science of the Total Environment.
323(1-3), 1-19.
https://doi.org/10.1016/j.scitotenv.2003.10.012
Richards LA. 1954. Diagnosis and improvement of saline and alkali soils. In: USDA, Ed.
Agriculture Handbook. USDA, Washington, DC, USA.
Shabani A, Sepaskhah AR, Kamgar Haghighi AA. 2013. Responses of agronomic components of
rapeseed (Brassica napus L.) as influenced by deficit irrigation, water salinity and planting
method. International Journal of Plant Production. 7(2), 313-340.
Sree Ramulu US. 1998. Management of water resources in agriculture. New Age International (P)
Limited. p. 106-112.
Wang X, Yang J, Liu G, Yao R, Yu S. 2015. Impact of irrigation volume and water salinity on winter
wheat productivity and salinity distribution. Agricultural Water Management. 149, 44-54.
https://doi.org/10.1016/j.agwat.2014.10.027
Yarami N, Sepaskhah AR. 2015. Saffron response to irrigation water salinity, cow manure and
planting method. Agricultural Water Management. 150, 57-66.

12
https://doi.org/10.1016/j.agwat.2014.12.004