scholarly journals Patterns of plant rehydration and growth following pulses of soil moisture availability

2020 ◽  
Author(s):  
Andrew F. Feldman ◽  
Daniel J. Short Gianotti ◽  
Alexandra G. Konings ◽  
Pierre Gentine ◽  
Dara Entekhabi
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Field Experiments ◽  
Annual Rainfall ◽  
Soil Conditions ◽  
Plant Water ◽  
Growth Responses ◽  
Individual Pulse ◽  
Initial Soil ◽  
Rain Pulses

Abstract. Plant hydraulic and photosynthetic responses to individual rain pulses are not well understood because pulse experiments are sparse. Understanding individual pulse responses would inform how rainfall intermittency impacts terrestrial biogeochemical cycles, especially in drylands which play a large role in global atmospheric carbon uptake interannual variability. Using satellite-based estimates of predawn plant and soil water content from the Soil Moisture Active Passive (SMAP) satellite, we quantify the timescales of plant water content increases following rainfall pulses, which we expect bear the signature of whole-plant mechanisms. In wetter regions, we find that plant water content increases rapidly and dries along with soil moisture, which we attribute to predawn soil-plant water potential equilibrium. Global drylands, by contrast, show multi-day plant water content increases after rain pulses. Shorter increases are more common following dry initial soil conditions. These are attributed to slow plant rehydration due to high plant resistances using a plant hydraulic model. Longer multi-day dryland plant water content increases are attributed to pulse-driven growth, following larger rain pulses and wetter initial soil conditions. These dryland responses reflect widespread drought recovery rehydration responses and individual pulse-driven growth responses, which supports isolated field experiments. The response dependence on moisture pulse characteristics also implies ecosystem sensitivity to intra-annual rainfall intensity and frequency, which are expected to shift in a future climate.

scholarly journals Patterns of plant rehydration and growth following pulses of soil moisture availability

2021 ◽  
Vol 18 (3) ◽  
pp. 831-847
Author(s):  
Andrew F. Feldman ◽  
Daniel J. Short Gianotti ◽  
Alexandra G. Konings ◽  
Pierre Gentine ◽  
Dara Entekhabi
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Field Experiments ◽  
Annual Rainfall ◽  
Soil Conditions ◽  
Plant Water ◽  
Growth Responses ◽  
Individual Pulse ◽  
Initial Soil ◽  
Rain Pulses

Abstract. Plant hydraulic and photosynthetic responses to individual rain pulses are not well understood because field experiments of pulse behavior are sparse. Understanding individual pulse responses would inform how rainfall intermittency impacts terrestrial biogeochemical cycles, especially in drylands, which play a large role in interannual global atmospheric carbon uptake variability. Using satellite-based estimates of predawn plant and soil water content from the Soil Moisture Active Passive (SMAP) satellite, we quantify the timescales of plant water content increases following rainfall pulses, which we expect bear the signature of whole-plant mechanisms. In wetter regions, we find that plant water content increases rapidly and dries along with soil moisture, which we attribute to predawn soil–plant water potential equilibrium. Global drylands, by contrast, show multi-day plant water content increases after rain pulses. Shorter increases are more common following dry initial soil conditions. These are attributed to slow plant rehydration due to high plant resistances using a plant hydraulic model. Longer multi-day dryland plant water content increases are attributed to pulse-driven growth, following larger rain pulses and wetter initial soil conditions. These dryland responses reflect widespread drought recovery rehydration responses and individual pulse-driven growth responses, as supported by previous isolated field experiments. The response dependence on moisture pulse characteristics, especially in drylands, also shows ecosystem sensitivity to intra-annual rainfall intensity and frequency, which are shifting with climate change.

scholarly journals Enhancing Soil Water Content for Increased Food Production in Semi-Arid Areas of Kenya Results From an On-Farm Trial in Mwala District, Kenya

2014 ◽  
Vol 6 (4) ◽  
pp. 125 ◽  
Author(s):  
Anne Karuma ◽  
Peter Mtakwa ◽  
Nyambilila Amuri ◽  
Charles K. Gachene ◽  
Patrick Gicheru
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Conservation ◽  
Crop Yields ◽  
Conservation Tillage ◽  
Cropping Systems ◽  
Soil Conditions ◽  
Tillage Methods

Soil water conservation through tillage is one of the appropriate ways of addressing soil moisture deficit in rainfed agriculture. This study evaluated the effects of tillage practices on soil moisture conservation and crop yields in Mwala District, Eastern Kenya during the long rains (LR) and short rains (SR) of 2012/13. Six tillage systems: Disc plough (MB), Disc plough and harrowing (MBH), Ox-ploughing (OX), Subsoiling – ripping (SR), Hand hoe and Tied Ridges (HTR) and Hand hoe only (H) and, three cropping systems namely, sole maize, sole bean and maize - bean intercrop, were investigated in a split-plot design with four replicates. Data on soil water content was monitored at different weeks after planting and the crop yields at end of each growing season. A three-season average shows that soil water content and crop yields were higher in conventional tillage methods compared to the conservation tillage methods. Long term tillage experiments are thus required at different locations, under various environmental and soil conditions to validate the study findings.

scholarly journals Study on Runoff and Infiltration for Expansive Soil Slopes in Simulated Rainfall

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 222
Author(s):  
Wenkai Lei ◽  
Hongyuan Dong ◽  
Pan Chen ◽  
Haibo Lv ◽  
Liyun Fan ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Moisture Content ◽  
Expansive Soil ◽  
Slope Gradient ◽  
Initial Soil Moisture ◽  
Initial Soil

In order to understand the hydrological process of expansive soil slopes, simulated rainfall experiments were conducted to study the effects of slope gradient and initial soil moisture content on runoff and infiltration for expansive soil slopes located in south China. The field program consisted of four neighboring slopes (70%, 47%, 32%, and 21%) instrumented by a runoff collection system and moisture content sensors (EC-5). Results from the monitored tests indicate that there was delay in the response of surface runoff. The runoff initiation time decreased with initial soil water content and increasing slope gradient. After the generation of runoff, the cumulative runoff per unit area and the runoff rate increased linearly and logarithmically with time, respectively. The greater the initial soil moisture content was, the smaller the influence of slope gradient on runoff. A rainfall may contribute from 39% to about 100% of its total rainfall as infiltration, indicating that infiltration remained an important component of the rainwater falling on the slope, despite the high initial soil water content. The larger the initial sealing degree of slope surface was the smaller the cumulative infiltration per unit area of the slope. However, the soil moisture reaction was more obvious. The influence of inclination is no longer discernible at high initial moisture levels. The greater the initial soil moisture content and the smaller the slope gradient, the weaker was the change of soil water content caused by simulated rainfall. The influence of initial soil moisture content and slope gradient on the processes of flow and changes of soil water content identified in this study may be helpful in the surface water control for expansive soil slopes.

An assessment of the impact of initial soil conditions on drought and precipitation extremes by using a high-resolution regional climate model

2021 ◽  
Author(s):  
Juan José Rosa Cánovas ◽  
Matilde García-Valdecasas Ojeda ◽  
Patricio Yeste-Donaire ◽  
Emilio Romero-Jiménez ◽  
María Jesús Esteban-Parra ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Initial Conditions ◽  
Regional Climate ◽  
Precipitation Extremes ◽  
Weather Research And Forecasting ◽  
Soil Conditions ◽  
Forecasting Model ◽  
Initial Soil ◽  
Dry Conditions ◽  
The Impact

<p>Soil moisture (SM) is one of the fields with a relevant role in processes involving land-atmosphere interactions, especially in regions such as the Mediterranean Europe, where coupling between those components of the climate system is very strong. The aim of this study is to address the impact of initial soil conditions on drought and precipitation extremes over the Iberian Peninsula (IP). For this purpose, a dynamical downscalling experiment has been conducted by using the Weather Research and Forecasting model (WRF) along the period 1990-2000. Two one-way nested domains has been considered: a finer domain spanning the IP, with spatial resolution around 10 km, nested within a coarser domain covering the Euro-CORDEX region at 50 km of spatial resolution.</p><p>WRF simulations have been driven with ERA-Interim reanalysis data for all fields except for SM. Initial SM conditions can be divided into three different types: wet, dry and very dry. Values corresponding to initial SM states have been calculated by combining the WRF soil texture map along with the Soil Moisture Index (SMI). For wet conditions, SMI = 1 has been assigned; for dry conditions, SMI = -0.5; and for very dry conditions, SMI = -1. For a grid point with a given texture class, field capacity, wilting point and SMI are used to obtain initial SM. Two different initial dates have been taken into account to also consider the effect of initializing at different moments in the year: 1990-01-01 00:00:00 UTC and 1990-07-01 00:00:00 UTC. Therefore, 6 experimental runs have been carried out (2 initial dates x 3 initial SM). Additionally, a control run full-driven with ERA-Interim has been conducted from 1982 to 2000 to be used as reference. In this context, the impact of initial conditions on different extreme precipitation indices (R5xDay, SDII and R10mm) and on the Standardized Precipitation Index (SPI) for drought has been addressed.</p><p>Results could help to better understand the relevance of land-atmosphere processes in climate modeling, particularly in assessing WRF sensitivity to variations in SM and its skill to detect drought and precipitation extremes. This information could be notably useful in those applications in which initial conditions are especially relevant, such as the seasonal-to-decadal climate prediction.</p><p>Keywords: soil moisture, initial conditions, precipitation extremes, drought, regional climate, Weather Research and Forecasting model</p><p>ACKNOWLEDGEMENTS: JJRC acknowledges the Spanish Ministry of Science, Innovation and Universities for the predoctoral fellowship (grant code: PRE2018-083921). This research has been carried out in the framework of the projects CGL2017-89836-R, funded by the Spanish Ministry of Economy and Competitiveness with additional FEDER funds, and B-RNM-336-UGR18, funded by FEDER / Junta de Andalucía - Ministry of Economy and Knowledge.</p>

A survey on the soil penetration resistance and soil moisture content in field experiments

2011 ◽  
Vol 59 (4) ◽  
pp. 349-359
Author(s):  
P. Földesi ◽  
C. Gyuricza
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Physical Condition ◽  
Soil Compaction ◽  
Field Experiments ◽  
Soil Moisture Content ◽  
Penetration Resistance ◽  
Soil Conditions ◽  
Environmental Damage ◽  
Soil Penetration Resistance

Various forms of physical soil degradation, including soil compaction, have been widely investigated both in Hungary and abroad. Soil compaction is a world-scale problem, which may be triggered by both natural and artificial factors and may adversely influence the effectiveness of crop production. In the long run this unfavourable change in the physical condition of the soil may result in extra expenses, higher energy consumption and excessive environmental damage. The effect of conventional tillage on the physical condition of the soil was assessed on six farms for three years in the framework of field experiments. In this study the physical condition of the soil was examined in terms of soil penetration resistance and moisture content. Significant differences between the experiments were revealed when penetration resistance (PR) was examinated at a depth of 20–30 cm, but not at other depths. In 2004 the mean PR values exceeded 3 MPa in experiments A, B and E. In 2005 significant differences were observed between the experiments at a depth of 30–40 cm, but no adverse compaction was detected at any depth in any of the experiments. In 2006 significant differences were observed between the experiments at depths of 0–10 cm and 10–20 cm, though even in that year no adverse soil compaction was detected. In the first year significant differences in soil moisture content were revealed at depths of 10–20 cm, 20–30 cm, 30–40 cm and 40–50 cm, and in 2005 at depths of 20–30 cm and 30–40 cm. In 2006 no significant differences were found between the experiments at any depth. The highest soil moisture contents were recorded in all the experiments at a depth of 30–40 cm. All in all, the results of both penetration resistance and moisture content were indicative of favourable soil conditions. During the period investigated adversely compact layers that would hamper moisture transport were not found in any of the experiments.

Rainfall Conservation and The Yields Of Sorghum and Groundnuts in Northern Nigeria

1966 ◽  
Vol 2 (2) ◽  
pp. 139-146 ◽  
Author(s):  
D. A. Lawes
Keyword(s):  
Soil Moisture ◽  
Field Experiments ◽  
Soil Surface ◽  
Infiltration Rate ◽  
Soil Conditions ◽  
Northern Nigeria ◽  
Seed Cotton ◽  
High Yields ◽  
Cultivation Techniques ◽  
Poor Soil

SummaryThe use of cultivation techniques to conserve rainfall, by preventing runoff, and to improve the soil surface infiltration rate, has produced spectacular increases in the yield of cotton on the Loess Plain soils of Northern Nigeria, where yields of the order of 2000 lb seed cotton per acre can now be produced regularly irrespective of the rainfall pattern. As yields of this level had not been obtained previously, it has been concluded that lack of soil moisture and poor soil aeration have in the past set a ceiling to seed cotton yields. The effects of these cultivation treatments on the two other major crops of the area, sorghum and groundnuts, have now been examined, and results from a series of field experiments over six seasons indicate that adequate soil moisture is essential to the production of high yields, but that the other soil conditions which are alleviated by these cultivations are not so critical for these two crops as they are for cotton. Reasons are suggested why spectacular increases in yield in response to the treatments are not generally to be expected with sorghum and groundnuts.

scholarly journals A soil moisture and temperature network for SMOS validation in Western Denmark

2011 ◽  
Vol 8 (6) ◽  
pp. 9961-10006 ◽  
Author(s):  
S. Bircher ◽  
N. Skou ◽  
K. H. Jensen ◽  
J. P. Walker ◽  
L. Rasmussen
Keyword(s):  
Soil Moisture ◽  
Environmental Conditions ◽  
Land Surface ◽  
Open Water ◽  
Soil Conditions ◽  
Present Sample ◽  
Minimal Impact ◽  
Initial Soil Moisture ◽  
North East ◽  
Initial Soil

Abstract. The Soil Moisture and Ocean Salinity Mission (SMOS) acquires surface soil moisture data globally, and thus product validation for a range of climate and environmental conditions across continents is a crucial step. For this purpose, a soil moisture and temperature network of Decagon ECH2O 5TE capacitance sensors was established in the Skjern River Catchment, Denmark. The objectives of this article are to describe a method to implement a network suited for SMOS validation, and to present sample data collected by the network to verify the approach. The design phase included (1) selection of a single SMOS pixel (44 × 44 km), which is representative of the land surface conditions of the catchment and with minimal impact from open water (2) arrangement of three network clusters along the precipitation gradient, and (3) distribution of the stations according to respective fractions of classes representing the prevailing environmental conditions. Overall, measured moisture and temperature patterns could be related to the respective land cover and soil conditions. Texture-dependency of the 0–5 cm soil moisture measurements was demonstrated. Regional differences in 0–5 cm soil moisture, temperature and precipitation between the north-east and south-west were found to be small. A first comparison between the 0–5 cm network averages and the SMOS soil moisture (level 2) product is in range with worldwide validation results, showing comparable trends for SMOS retrieved/initial soil moisture and initial temperature (R2 of 0.49/0.67 and 0.97, respectively). While retrieved/initial soil moisture indicate significant under-/overestimation of the network data (biases of −0.092/0.057 m3 m−3), temperature is in good agreement (bias of −0.2 °C). Consequently, the network performs according to expectations and proves to be well-suited for its purpose. The discrepancies between network and SMOS soil moisture will be subject of subsequent studies.

scholarly journals Optimization-Based Water-Salt Dynamic Threshold Analysis of Cotton Root Zone in Arid Areas

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2449
Author(s):  
Hui Wu ◽  
Shaozhong Kang ◽  
Xiaojuan Li ◽  
Ping Guo ◽  
Shunjun Hu
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Root Zone ◽  
Growth Stages ◽  
Cotton Yield ◽  
Threshold Levels ◽  
Initial Soil ◽  
Different Growth Stages

Threshold levels of soil moisture and salinity in the plant root zone can guide crop planting and farming practices by providing a baseline for adjusting irrigation and modifying soil salinity. This study describes a method of soil water and salinity control based on an optimized model for growing cotton in an arid area. Experiments were conducted in Akesu Irrigation District, southern Xinjiang, northwest China, to provide data for cotton yield and soil water content and salinity in the root zone at different growth stages. The sensitivity of cotton to soil water content and salinity was predicted for different growth periods using a modified Jensen model. An optimization model with 480 boundary conditions was created, with the objective of maximizing yield, to obtain the dynamically varying water and salt threshold levels in the root zone for scenarios that included three initial soil moisture content values (W0), eight irrigation quantities (M), five initial soil salt content values (S0), and four irrigation water salinity levels (K). Results showed that the flowering–boll stage is the crucial period for cotton yield, and the threshold levels of soil water content and salinity in the cotton root zone varied with the boundary conditions. The scenario chosen for the research area in this study was W0 = 0.85θfc (θfc is field capacity), S0 = 4 g kg−1, M = 400 mm, K = 0 g L−1. The predicted threshold levels of soil water for different growth stages (seedling, bud, flowering–boll, and boll-opening) were respectively 0.75–0.85θfc, 0.65–0.75θfc, 0.56–0.65θfc, and 0.45–0.56θfc. Corresponding threshold levels of salt were 4–4.16, 4.16–4.39, 4.39–4.64, and 4.64–4.97 g kg−1 when no action was taken to remove salt from the root zone. This study provides an innovation method for the determination of dynamically varying soil water content and salt thresholds.

Studies on field establishment of monogerm sugar beet

1973 ◽  
Vol 81 (2) ◽  
pp. 245-252 ◽  
Author(s):  
D. A. Perry
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Sugar Beet ◽  
Soil Compaction ◽  
Field Experiments ◽  
Soil Moisture Content ◽  
Rank Order ◽  
Soil Conditions ◽  
High Soil Moisture ◽  
High Soil

SummaryThe percentage emergence from monogerm sugar-beet seed in field experiments was reduced by high soil moisture content and soil compaction, but was unaffected by soil temperature. Seed lots were differentially influenced when the soil conditions were very adverse. Pelleted seed emerged a little better in good soil conditions and was not more sensitive to high soil moisture content than raw seed.The relation between laboratory germination and the number of emerged seedlings was variable and followed no obvious trends, and there was no consistent rank order in the emergence ability of four commercial cultivars.

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