scholarly journals Spatial variability and temporal stability of water storage in a cultivated tropical soil

Bragantia ◽  
2010 ◽  
Vol 69 (suppl) ◽  
pp. 153-162 ◽  
Author(s):  
Antonio Carlos Andrade Gonçalves ◽  
Marcos Antonio Trintinalha ◽  
Marcos Vinicius Folegatti ◽  
Roberto Rezende ◽  
Cássio Antonio Tormena
Keyword(s):  
Water Content ◽  
Soil Water ◽  
High Efficiency ◽  
Temporal Stability ◽  
Water Storage ◽  
Soil Surface ◽  
Soil Water Storage ◽  
Soil Conditions ◽  
Content Uniformity ◽  
Water Application

Irrigated agricultural fields usually show variable crop water demand. If water application is done to match this spatially variable demand, the water use efficiency can be substantially improved. Soil water management by irrigation has been one of the most important factors to increase crop yield. To look for the economic viability of the process, the use of several inputs, particularly water, should be done with high efficiency levels. Historically, irrigation uniformity has been evaluated above the soil surface, in which applied water was the only factor to be taken into account. However, the crop will respond to soil water content uniformity, which can differ from the uniformity of water application. To evaluate temporal stability of spatial pattern of soil water storage (SWS), this work was done on a Brazilian clayed soil. Volumetric water content from soil surface to 0,30m depth, was measured by TDR in 80 points regularly spaced (3 x 3 m) on an experimental area cultivated with bean crop, irrigated by conventional sprinkling. The evaluations were done immediately before and after a water application by irrigation. Experimental semivariograms made from values obtained in the field showed that SWS distribution was spatially structured and strongly stable in time, being regulated mainly by intrinsic factors of the soil. In addition, obtained results showed that water application uniformity did not influence the spatial distribution pattern of SWS in these soil conditions.

scholarly journals Soil Water Storage Temporal Stability With and Without Outliers

2020 ◽  
Vol 12 (11) ◽  
pp. 234
Author(s):  
Alexsandro dos Santos Brito ◽  
Paulo Leonel Libardi ◽  
Jaedson Cláudio Anunciato Mota ◽  
Sergio Oliveira Moraes
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Root Zone ◽  
Water Flux ◽  
Temporal Stability ◽  
Water Storage ◽  
Temporal Distribution ◽  
Soil Water Storage ◽  
Sampling Points

The knowledge on the temporal stability of spatial variability of soil water storage in the crops’ root zone is of fundamental importance for soil and water management. The objective of this work was to characterize the temporal distribution of water storage in a Latossolo vermelho amarelo and identify field locations with spatial patterns of high, intermediate and low soil water storage, in 13 samplings every 14 days. The assessed period included periods of drying and water recharge of the soil, along which soil water content was determined at 60 sampling points arranged in a 5 × 5 m grid covering an area of 1250 m2 (25 × 50 m). Soil water content was determined by means of a neutron probe, at soil depths of 0.2, 0.4, 0.6, 0.8 and 1.0 m. Soil water storage was calculated by Simpson’s rule and data were analyzed by the temporal persistence of the spatial pattern. Maximum values of soil water storage were obtained at the portion of the area with water flux concentration (sampling points 4, 28 and 57), with and without outliers, and low values of soil water storage were obtained at the highers levels of the site (sampling points 12, 18 and 19), with and without outliers. The sites representing the mean soil water storage were 32, 51 and 11, considering outliers, and 8, 11 and 53, without considering outliers.

scholarly journals Energy balance closure on a winter wheat stand: comparing the eddy covariance technique with the soil water balance method

2016 ◽  
Vol 13 (1) ◽  
pp. 63-75 ◽  
Author(s):  
K. Imukova ◽  
J. Ingwersen ◽  
M. Hevart ◽  
T. Streck
Keyword(s):  
Energy Balance ◽  
Water Balance ◽  
Winter Wheat ◽  
Water Content ◽  
Soil Water ◽  
Water Storage ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
Water Balance Method ◽  
Closure Method

Abstract. The energy balance of eddy covariance (EC) flux data is typically not closed. The nature of the gap is usually not known, which hampers using EC data to parameterize and test models. In the present study we cross-checked the evapotranspiration data obtained with the EC method (ETEC) against ET rates measured with the soil water balance method (ETWB) at winter wheat stands in southwest Germany. During the growing seasons 2012 and 2013, we continuously measured, in a half-hourly resolution, latent heat (LE) and sensible (H) heat fluxes using the EC technique. Measured fluxes were adjusted with either the Bowen-ratio (BR), H or LE post-closure method. ETWB was estimated based on rainfall, seepage and soil water storage measurements. The soil water storage term was determined at sixteen locations within the footprint of an EC station, by measuring the soil water content down to a soil depth of 1.5 m. In the second year, the volumetric soil water content was additionally continuously measured in 15 min resolution in 10 cm intervals down to 90 cm depth with sixteen capacitance soil moisture sensors. During the 2012 growing season, the H post-closed LE flux data (ETEC =  3.4 ± 0.6 mm day−1) corresponded closest with the result of the WB method (3.3 ± 0.3 mm day−1). ETEC adjusted by the BR (4.1 ± 0.6 mm day−1) or LE (4.9 ± 0.9 mm day−1) post-closure method were higher than the ETWB by 24 and 48 %, respectively. In 2013, ETWB was in best agreement with ETEC adjusted with the H post-closure method during the periods with low amount of rain and seepage. During these periods the BR and LE post-closure methods overestimated ET by about 46 and 70 %, respectively. During a period with high and frequent rainfalls, ETWB was in-between ETEC adjusted by H and BR post-closure methods. We conclude that, at most observation periods on our site, LE is not a major component of the energy balance gap. Our results indicate that the energy balance gap is made up by other energy fluxes and unconsidered or biased energy storage terms.

The impact of wheat stubble on evaporation from a sandy soil

2009 ◽  
Vol 60 (8) ◽  
pp. 730 ◽  
Author(s):  
P. R. Ward ◽  
K. Whisson ◽  
S. F. Micin ◽  
D. Zeelenberg ◽  
S. P. Milroy
Keyword(s):  
Soil Water ◽  
Sandy Soil ◽  
Water Storage ◽  
Soil Water Storage ◽  
Soil Conditions ◽  
Adjacent Area ◽  
Stubble Retention ◽  
Dry Conditions ◽  
Wheat Stubble ◽  
The Impact

In Mediterranean-type climates, dryland soil water storage and evaporation during the hot and dry summer are poorly understood, particularly for sandy-textured soils. Continued evaporation during summer, and any effects of crop stubble management, could have a significant impact on annual components of the water balance and crop yield. In this research, the effect of wheat stubble management on summer evaporation and soil water storage was investigated for a sandy soil in south-western Australia, during the summers of 2005–06 and 2006–07. Treatments comprised: retained standing stubble; retained flattened stubble; removed stubble; and removed stubble followed by burying the crowns with topsoil from an adjacent area. Under ‘dry’ conditions, evaporation continued at ~0.2 mm/day. In contrast to previous results for finer textured soil types, stubble retention did not decrease the rate of evaporation, but marginally (10–30%) increased evaporation on 7 out of 14 days when measurements were taken. Significant differences due to stubble management were observed in two successive summers, but only for relatively dry soil conditions. There were no significant differences observed for several days after irrigation or rainfall. Under dry conditions in the absence of rainfall, total decrease in water storage during a 90-day summer period could be ~20 mm, but differences attributable to stubble management are likely to be a few mm.

Use of Time-Domain Reflectometry (TDR) to measure the water-content of sandy soils

Soil Research ◽  
1995 ◽  
Vol 33 (2) ◽  
pp. 265 ◽  
Author(s):  
PJ Gregory ◽  
R Poss ◽  
J Eastham ◽  
S Micin
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Transmission Lines ◽  
Time Domain ◽  
Water Storage ◽  
Sandy Soils ◽  
Time Domain Reflectometry ◽  
Soil Water Storage ◽  
Use Of Time ◽  
Daily Evaporation

We investigated the potential sources of error when using time domain reflectometry (TDR) to measure the water content of sandy soils and evaluated the technique as a means of measuring evaporation from columns of soil and changes in soil water storage beneath crops. Inaccurate depth location of the transmission lines or the development of a hole at the tip of the transmission lines introduced an error about 10 times larger than the errors associated with hardware and software. Calibration in two sandy soils gave a curve of similar shape to that found by others except for values of dielectric constant < 6 when measured values of water content were less than those expected. Daily evaporation from soil columns measured by weighing and with TDR showed large differences between the two techniques (up to 32%) but compensating errors over time allowed cumulative evaporation to be estimated with TDR to within 6.6% of that determined by weighing over a 162 h period. Under field conditions, the agreement between TDR and neutron probe measures of changes in soil water storage in the upper 0.3 m was good and generally within 10% over both 14 day and longer periods.

Soil water changes under fallow-crop treatments in relation to soil type, rainfall and yield of wheat

1971 ◽  
Vol 11 (49) ◽  
pp. 236 ◽  
Author(s):  
JE Schultz
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Storage ◽  
South Australia ◽  
Soil Types ◽  
Soil Water Storage ◽  
Fallow Period ◽  
One Year ◽  
Water Contents ◽  
Soil Water Contents

Soil water changes under fallow (initial cultivation in spring), grassland (initial cultivation in autumn) and the succeeding wheat crops were recorded at two to three weekly intervals in three consecutive seasons in three soil types representing the range of wheat-growing soils in South Australia. Differences in water content between the two treatments developed soon after the start of fallowing due to the greater loss of water from grassland in spring. Rainfall during the fallow period contributed little to soil water storage except in one year when heavy spring rains were recorded. In some instances the water content in the fallowed soils at seeding was less than at the start of fallowing, but the fallowed soils consistently retained more water than the grassland soils. Soil water contents decreased after August of the crop year (end of tillering) and by harvest the wheat crops had commonly dried the soil to a depth of 150 cm. Fallow crops used more water and produced significantly higher wheat yields with a greater efficiency of water use in all trials.

How do spatial throughfall patterns reflect in soil moisture patterns?

2021 ◽  
Author(s):  
Christine Fischer ◽  
Murray Lark ◽  
Johanna C. Metzger ◽  
Thomas Wutzler ◽  
Anke Hildebrandt
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Temporal Stability ◽  
Water Storage ◽  
Rainfall Event ◽  
Content Increase ◽  
Water Content Increase ◽  
Air Capacity

&lt;div&gt; &lt;p&gt;This study investigates whether and how vegetation cover affects the spatial heterogeneity and vertical penetration of water through the Upper Critical Zone (UCZ). We assessed rainfall, throughfall and soil water contents on a 1&amp;#8208;ha temperate mixed beech forest plot in Germany. Throughfall and soil water content in two depths (7.5 cm and 27.5 cm) were measured on an event basis during the 2015 - 2016 growing season in independent high&amp;#8208;resolution stratified random designs. We calculated the increase of soil water content (&amp;#916;&amp;#952;) due to the rainfall by the difference between measurements at the beginning (pre-event) and the maximum soil water content after the end of rainfall event (post-event). Since throughfall and soil water content cannot be assessed at the same location, we used kriging to derive the throughfall values at the locations where soil water content was measured. We explore the spatial variation and temporal stability of throughfall and soil water content and evaluate the effects of throughfall, soil properties (field capacity and air capacity), and vegetation parameters (next tree distance) on soil water content variability.&lt;/p&gt; &lt;p&gt;Throughfall patterns were related to canopy density although correlation length decreased with increasing event size. Temporal stability was high, leading to persistently high and lower input locations across rainfall events.&lt;/p&gt; &lt;p&gt;A linear mixed effect model analysis confirmed that the soil water content increase due to precipitation depended on throughfall patterns, in that more water was stored in the soil where throughfall was enhanced. This was especially the case in large events and in both investigated soil depths. However, we also identified additional factors that enhanced or decreased water storage in the soil, and probably indicate fast drainage and runoff components. Locations with low topsoil water content tended to store less of the available water, indicating the role of preferential flow. In contrast in subsoil, locations with high water content, and probably poor drainage, stored less water, indicating lateral flow. Also, distance to the next tree and air capacity modified soil water storage.&lt;/p&gt; &lt;p&gt;Spatial soil water content patterns shortly before a rainfall event (pre-event conditions) seem to be a key factor in soil water content increase, and also explained much of soil water content shortly after the rainfall event. Pre-event soil water content was mostly driven by random local effects, probably microtopography and root water uptake, which were not quantified in this study. The remaining spatial variation was explained by air capacity in both soil layers, indicating the role of macroporosity.&lt;/p&gt; &lt;p&gt;Our findings show at the same time systematic patterns of times and locations where the soil capacity to store water is reduced and water probably conducted quickly to greater depth. Not only soil moisture patterns but also deeper percolation may depend on small scale spatial heterogeneity of canopy input patterns.&lt;/p&gt; &lt;/div&gt;

Sign in / Sign up

Export Citation Format

Share Document