28
Tecnología y Ciencias del Agua
, vol. VIII, núm. 2, marzo-abril de 2017, pp. 19-30
Fan
et al
.
, Effect of drip irrigation with saline water on the shelterbelts to soil and groundwater environment in the hinterland of Taklimakan Desert, China
•
ISSN 2007-2422
effect of the distributions of different irrigation
schedules to soil moisture and salt, plant growth
and groundwater chemical. It was revealed that
the irrigation has a relatively high impact on the
surface soil moisture, but a feeble one on deep
soil. The study of soil moisture in the direction
perpendicular to the horizon indicates that the
soil moisture varies slightly below a soil depth
of 100 cm (Wang
et al
., 2008). With the same age
of forest, the soil moisture gradually increases
from surface to deep soil (Zhang
et al
., 2008).
Other studies have shown that the distributions
of the soil water content at the capillary satura-
tion zone were determined by groundwater,
while vegetation could affect the soil salinity,
but not soil moisture (Wang
et al
., 2012).
The soil salt was continuously accumulated
to the surface soil body at a horizontal distance
of 20-140 cm from the dripper and a depth of
about 20 cm. It is in agreement with the salt
accumulation at the shifting aeolian sandy soil
surface (Zhang, 2008), and has different tem-
poral dynamics in an irrigation cycle (Zhang,
2016). In addition, some other factors also
influence the spatial distribution of soil salinity
such as soil spatial variability, groundwater salt
content (Huang
et al
., 2015; Rose, Konukcu, &
Gowing, 2005), because the clay soil is suitable
to adsorb soluble salt ions (Brantley S L. Geol-
ogy, 2008).
Some studies indicate that average soil mois-
ture above 6% in shelterbelts along the Tarim
Desert Highway can meet the requirement for
plant growth (Unterbrunner
et al
., 2007). By our
water-saving irrigation test, the plant growth
was not abnormal, while average soil moisture
above 21%, and 32% of water could be saved
when the irrigation treatment in region II was
used. Based on this work results, more efficient
irrigation methods can be elaborated for similar
applications.
Conclusions
Irrigation has relatively large impact on the
water content of surface soil, but has little ef-
fect on deep soil water content. In the layer
with root distribution, the soil water content of
each region could be maintained at a high level.
Three days after irrigation, the entire soil salin-
ity was significantly decreased, as compared to
that before irrigation, indicating that most salt
was infiltrated with water via the range from
soil surface to 30 cm entering the groundwater
body. The groundwater level, TDS and total
hardness exhibited an upward trend in the
shelterbelt area.
The plant growth showed no significant
variations under the impact of various ir-
rigation treatments. Based on the analysis of
variance, the response in the radial growth of
Tamarixramosissima
tree trunk is more sensitive
to water stress. Therefore, if the statistical results
obtained are verified and the height growth is-
sue of
Tamarixramosissima
is disregarded, then
at least 50% or more of water as well as the cor-
responding manpower and resources could be
saved when the entire area was irrigated with
the irrigation system in region IV. If the above
issue is considered, 32% of water could be saved
if the irrigation system of region II was used.
The results in this paper can provide a very
good theoretical support on the sustainability
study on desert shelterbelt systems, and also
show practical significance in the study of the
relationship between shelterbelt irrigation
volume and shelterbelt tree growth. However,
the investigation on the status of shelterbelt
plant growth is affected by subjective factors,
including standard plant selection, judgement
of observation staff, and differences in readings,
and objective factors, including observation
tools, micro-topography, soil heterogeneity
and observation time. The results of statistical
analysis can be affected to some degree. There-
fore, in order to obtain more accurate data, it is
necessary to strengthen the standardized opera-
tion for observers, adopt a more scientific and
convenient measurement instruments, increase
the observation density, and increase observed
sample density. Therefore, the data from a
longer scientific observation is still needed for
validation.
