A decreasing trend in global soil water storage from 1981 to 2017

2021 ◽  
Author(s):  
XinRui Luo ◽  
Shaoda Li ◽  
Wunian Yang ◽  
Liang Liu ◽  
Xiaolu Tang
Keyword(s):  
Soil Water ◽  
Water Loss ◽  
Root Zone ◽  
Carbon Sink ◽  
Temporal Trends ◽  
Water Storage ◽  
Terrestrial Ecosystems ◽  
Environmental Drivers ◽  
Soil Water Storage ◽  
Soil Drought

<p>Soil water storage serves as a vital resource of the terrestrial ecosystems, and it can significantly influence water cycle and carbon cycling with the frequent occurrence of soil drought induced by land-atmosphere feedbacks. However, there are high variations and uncertainties of root zone soil water storage. This study applied comparison map profile (CMP), Mann-Kendall test, Theil-Sen estimate and partial correlation analysis to (1) estimate the global root zone (0~1 m) soil water storage, (2) and investigate the spatial and temporal patterns from 1981 to 2017 at the global scale, (3) and their relationships with environmental drivers (precipitation, temperature, potential evaportranspiration) using three soil moisture (SM) products – ERA-5, GLDAS and MERRA-2. Globally, the average annual soil water storage from 1981 to 2017 varied significantly, ranging from 138.3 (100 Pg a<sup>-1</sup>, 1 Pg = 10<sup>15</sup> g) in GLDAS to 342.6 (100 Pg a<sup>-1</sup>) in ERA-5. Soil water storage of the three SM products consistently showed a decreasing trend. However, the temporal trend of soil water storage among different climate zones was different, showing a decreasing trend in tropical, temperate and cold zones, but an increasing trend in polar regions. On the other hand, temporal trends in arid regions differed from ERA-5, GLDAS and MERRA-2. Spatially, the SM products differed greatly, particularly for boreal areas with D value higher for 2500 Mg ha<sup>-1</sup> a<sup>-1</sup> and CC value lower for -0.2 between GLDAS and MERRA-2. Over 1981 to 2017, water storage of more than 50% of the global land area suffered from a decreasing trend, especially in Africa and Northeastern of China. Precipitation was the main dominated driver for variation of soil water storage, and distribution varied in different SM products. In conclusion, a global decreasing trend in soil water storage indicate a water loss from soils, and how the water loss affecting carbon sink in terrestrial ecosystems under ongoing climate change needs further investigation.</p>

scholarly journals Effects of Wheat and Rapeseed Production on Soil Water Storage in Mongolian Rangeland

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 888
Author(s):  
Katori Miyasaka ◽  
Takafumi Miyasaka ◽  
Jumpei Ota ◽  
Siilegmaa Batsukh ◽  
Undarmaa Jamsran
Keyword(s):  
Soil Water ◽  
Crop Production ◽  
Root Zone ◽  
Water Storage ◽  
Soil Water Storage ◽  
Matric Potential ◽  
Wheat Field ◽  
Long Time ◽  
Rapeseed Production ◽  
Wilting Point

In recent years, Mongolia has witnessed an increase in not only wheat fields, which have been present for a long time, but also rapeseed fields. This has led to increasing concerns about soil degradation due to inappropriate cultivation. This study aims to determine the impacts of rapeseed production on soil water storage in Mongolia. The soil water content and matric potential were measured in wheat and rapeseed fields and adjacent steppe rangeland for five years, including crop production and fallow years, and the soil water storages in the fields were compared. The results demonstrated that the matric potential below the root zone in the rapeseed field and both rangelands was drier than the wilting point, whereas the potential in the wheat field was usually almost the same or wetter than this point. The comparison of the amount of soil water storage during the fallow year with that of the adjacent rangeland showed it to be 5–10% higher for the wheat field and almost equal for the rapeseed field. Field management must consider the fact that rapeseed fields use more water than is required by wheat fields and that less water is stored during fallow periods.

ESTIMATING EVAPOTRANSPIRATION FROM IRRIGATED CROPS IN SOUTHWESTERN ONTARIO

1981 ◽  
Vol 61 (2) ◽  
pp. 425-435 ◽  
Author(s):  
C. S. TAN ◽  
J. M. FULTON
Keyword(s):  
Soil Water ◽  
Crop Yields ◽  
Root Zone ◽  
Sandy Loam ◽  
Sunshine Duration ◽  
Meteorological Data ◽  
Water Storage ◽  
Soil Water Storage ◽  
Climatic Data ◽  
Wide Range

Several years of daily evapotranspiration (ET) data for irrigated early potatoes, corn and processing tomatoes, grown on Fox sandy loam measured by floating lysimeters and estimated by meteorological data were used to evaluate an equilibrium evapotranspiration (ETeq) model. A reasonable relationship was obtained between values estimated by the model and those measured by floating lysimeters. The ETeq model can be used to estimate daily ET over a wide range of soil moisture and foliage cover conditions. ETeq can be estimated from readily available climatic data in the form: ETeq = (0.48 + 0.01 Ta) [(0.114 + 0.365n/N) K↓a − 0.039]; where Ta is the mean daily air temperature (°C); n is sunshine duration (h); N is maximum hours of bright sunshine (h); K↓a is solar energy received at the top of the atmosphere (mm/day). At high soil water storage in the root zone, the ET/ETeq remained constant, whereas, at low soil water storage, the ET/ETeq decreased linearly with decreasing soil water storage. The total crop yields were directly related to growing season accumulated ET.

Calculating Thornthwaite and Mather's actual evapotranspiration using an approximating function

1984 ◽  
Vol 14 (3) ◽  
pp. 466-467 ◽  
Author(s):  
J. Pastor ◽  
W. M. Post
Keyword(s):  
Soil Water ◽  
Exponential Function ◽  
Water Loss ◽  
Water Storage ◽  
Field Capacity ◽  
Actual Evapotranspiration ◽  
Soil Water Storage ◽  
Negative Exponential Function ◽  
Negative Exponential

A simple negative exponential function is presented which relates soil water storage to a maximum storage value (field capacity) and accumulated potential water loss. This formula summarizes 10 tables from Thornthwaite and Mather (Publications in Climatology, 10: 183–311, 1957) needed to calculate actual evapotranspiration (AET). Comparisons are presented for values predicted by this formula and Thornthwaite and Mather's tabulated values.

Water use of sunflower crops

1979 ◽  
Vol 19 (97) ◽  
pp. 233 ◽  
Author(s):  
WK Anderson
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Root Zone ◽  
Water Storage ◽  
Soil Water Storage ◽  
Evaporative Demand ◽  
Sowing Time ◽  
Small Component ◽  
Water Storage Capacity ◽  
Water Use Efficiencies

The potential, or energy-limited evapotranspiration, and the actual, or soil water-limited evapotranspiration functions of sunflower were estimated by lysimetry and field soil water measurements. The functions show that peak water demand by the crop is in the immediate post-anthesis period and that sunflower is capable of restricting its water use when some 70% of the maximum available water remains in the root zone. With the aid of these functions, weekly estimates were made of the water use of thirteen commercial sunflower crops in northern New South Wales. Estimated water use ranged from 150 to 320 mrn and water use efficiencies from 1.9 to 10.5 kg seed mm-1 water used. Highest yields and water use efficiencies were associated with a combination of high total water supply (soil water at sowing plus rainfall during growth of 380 mm or more) high water use (220 mm or more) and low evaporative demand (below 780 mm of pan evaporation). Based on the water use characteristics of the crop the optimal sowing time in most areas is mid summer. However, spring sowings may be preferable for winter rainfall areas where soil water storage capacity is high and there is only a small component of summer rain. Crops sown in spring, even with high stored soil water (up to 200 mm) failed to yield as well as those sown in summer with much lower soil water storage.

scholarly journals Comparison between climatological and field water balances for a coffee crop

2007 ◽  
Vol 64 (3) ◽  
pp. 215-220 ◽  
Author(s):  
Isabeli Pereira Bruno ◽  
Adriana Lúcia da Silva ◽  
Klaus Reichardt ◽  
Durval Dourado-Neto ◽  
Osny Oliveira Santos Bacchi ◽  
...  
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Water Storage ◽  
Crop Management ◽  
Soil Water Storage ◽  
Water Runoff ◽  
Available Water ◽  
Water Balances ◽  
Runoff Losses

The use of climatological water balances in substitution to complete water balances directly measured in the field allows a more practical crop management, since the climatological water balances are based on data monitored as a routine. This study makes a comparison between these methods in terms of estimatives of evapotranspiration, soil water storage, soil available water, runoff losses, and drainage below root zone, during a two year period, taking as an example a coffee crop of the variety Catuaí, three to five years old. Climatological water balances based on the estimation of the evapotranspiration through the methods of Thornthwaite and Penman-Monteith, can reasonably substitute field measured balances, however underestimating the above mentioned variables.

Impact of three and seven years of no-tillage on the soil water storage, in the plant root zone, under a dry subhumid Tunisian climate

2013 ◽  
Vol 126 ◽  
pp. 26-33 ◽  
Author(s):  
Imene Jemai ◽  
Nadhira Ben Aissa ◽  
Saida Ben Guirat ◽  
Moncef Ben-Hammouda ◽  
Tahar Gallali
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Plant Root ◽  
Water Storage ◽  
Soil Water Storage ◽  
No Tillage

The effect of long-term fertilization on soil water storage and water deficit in the Black Soil Zone in northeast China

2012 ◽  
Vol 92 (3) ◽  
pp. 439-448 ◽  
Author(s):  
Wenxiu Zou ◽  
Bingcheng Si ◽  
Xiaozeng Han ◽  
Heng Jiang
Keyword(s):  
Soil Water ◽  
Water Deficit ◽  
Northeast China ◽  
Root Zone ◽  
Water Storage ◽  
Black Soil ◽  
Soil Water Storage ◽  
Soil Water Deficit ◽  
Soil Zone

Zou, W., Si, B., Han, X. and Jiang, H. 2012. The effect of long-term fertilization on soil water storage and water deficit in the Black Soil Zone in northeast China. Can. J. Soil Sci. 92: 439–448. The Black Soil Zone in northeast China is one of the most important areas of agricultural production in China and plays a crucial role in food supply. However, further improvement in crop yield hinges on effective management of soil water. There is a poor understanding of how different fertilization methods affect crop water use efficiency. The objective of this study was to examine the effect of different fertilization methods on soil water storage and deficit in Black soils. A long-term experiment was conducted at the National Field Research Station of Agro-ecosystems, at Hailun County, Heilongjiang province in northeastern China from 1999 to 2008. Three fertilizer treatments including no fertilizer (CK), inorganic fertilizer (NP) and inorganic fertilizer plus organic material (NPM) were tested. The results showed that soil water storage decreased in the order CK, NP, and NPM during the growing season and the differences in soil water storage in the active root zone (0–70 cm) and below the active root zone (70–130 cm) and soil water deficit were statistically significant among the three treatments. Due to the uneven temporal distribution of rainfall and crop water uptake, soil water content was very dynamic in all three treatments: The low soil water storage and resulting soil water deficit (defined as the monthly difference between potential evapotranspiration and soil available water storage) within the 0- to 70-cm soil profile were found in both June and July. Further, soil receiving NPM was more likely to have a soil water deficit, but less likely to have excessive water. A lower risk of excess water may result in deeper root penetration and increased water use at greater depth, and thus the water deficit under the NPM treatment may not be the limiting factor for crop production. Therefore, NPM seems a viable management practice for improving crop yields in the Black Soil Zone in northeast China, possibly due to higher soil organic carbon and nutrient supply and lower probability of excess water.

scholarly journals Water storage change estimation from in situ shrinkage measurements of clay soils

2013 ◽  
Vol 17 (5) ◽  
pp. 1933-1949 ◽  
Author(s):  
B. te Brake ◽  
M. J. van der Ploeg ◽  
G. H. de Rooij
Keyword(s):  
Soil Water ◽  
Volume Change ◽  
Water Loss ◽  
Water Storage ◽  
Bulk Soil ◽  
Soil Water Storage ◽  
Dry Period ◽  
Soil Layers ◽  
Storage Change

Abstract. The objective of this study is to assess the applicability of clay soil elevation change measurements to estimate soil water storage changes, using a simplified approach. We measured moisture contents in aggregates by EC-5 sensors, and in multiple aggregate and inter-aggregate spaces (bulk soil) by CS616 sensors. In a long dry period, the assumption of constant isotropic shrinkage proved invalid and a soil moisture dependant geometry factor was applied. The relative overestimation made by assuming constant isotropic shrinkage in the linear (basic) shrinkage phase was 26.4% (17.5 mm) for the actively shrinking layer between 0 and 60 cm. Aggregate-scale water storage and volume change revealed a linear relation for layers ≥ 30 cm depth. The range of basic shrinkage in the bulk soil was limited by delayed drying of deep soil layers, and maximum water loss in the structural shrinkage phase was 40% of total water loss in the 0–60 cm layer, and over 60% in deeper layers. In the dry period, fitted slopes of the ΔV–ΔW relationship ranged from 0.41 to 0.56 (EC-5) and 0.42 to 0.55 (CS616). Under a dynamic drying and wetting regime, slopes ranged from 0.21 to 0.38 (EC-5) and 0.22 to 0.36 (CS616). Alternating shrinkage and incomplete swelling resulted in limited volume change relative to water storage change. The slope of the ΔV–ΔW relationship depended on the drying regime, measurement scale and combined effect of different soil layers. Therefore, solely relying on surface level elevation changes to infer soil water storage changes will lead to large underestimations. Recent and future developments might provide a basis for application of shrinkage relations to field situations, but in situ observations will be required to do so.

Drainage and change in soil water storage below the root-zone under long fallow and continuous cropping sequences in the Victorian Mallee

2003 ◽  
Vol 54 (7) ◽  
pp. 663 ◽  
Author(s):  
Mark G. O'Connell ◽  
Garry J. O'Leary ◽  
David J. Connor
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Sandy Loam ◽  
Water Storage ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Continuous Cropping ◽  
Deep Drainage ◽  
Mean Annual Rainfall ◽  
Fallow System

A field study investigated drainage and changes in soil water storage below the root-zone of annual crops on a sandy loam soil in the Victorian Mallee for 8 years. It was designed to compare the effects of the common long (18-month) fallow in a 3-year rotation (fallow–wheat–pea, FWP) with a rotation in which the fallow was replaced with mustard (Brassica juncea), viz. mustard–wheat–pea (MWP). Drainage was measured over 2 periods (1993–98 and 1998–2001) using 9 in situ drainage lysimeters in each rotation. The first period of ~5 years was drier than average (mean annual rainfall 298 cf. 339 mm) and drainage was low and variable. Drainage was greater under the fallow rotation (average 0.24 mm/year) than under the non-fallow rotation (average <0.01 mm/year). The result for the fallow rotation did, however, include one lysimeter that recorded substantial drainage (10.6 mm over the 5 years). During the second period of measurement (~3 years), rainfall was above average (mean annual rainfall 356 cf. 339�mm) and drainage was greater. On average, drainage from the fallow rotation was 6.7 mm/year compared with the non-fallow rotation at 4.0 mm/year. There was again substantial variation between lysimeters. One lysimeter under MWP recorded 31.4 mm/year, and as in the earlier drier period, there were many lysimeters that recorded no drainage. During the drier first period (1993–98), changes in soil water storage between 1.5 and 5.5 m depth confirmed the tendency of the fallow rotation to increase deep drainage. Despite increases and decreases in subsoil water storage during the study, the cumulative change in water storage was positive and greatest under FWP (range: 2.8–14.8 mm/year, ave. 9.6 mm/year) compared with MWP (range: 5.3–9.8 mm/year, ave. 7.4 mm/year) cropping sequences. Overall, the long fallow system has the potential to increase deep drainage by approximately 2 mm/year compared with a fully cropped system, over a wide annual rainfall range (134–438 mm). Further, this experiment reinforces the focus for the reduction of fallow practices for dryland salinity control in the Mallee region.

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