scholarly journals Grafted Watermelon Root Length Density and Distribution under Different Soil Moisture Treatments

HortScience ◽  
2013 ◽  
Vol 48 (8) ◽  
pp. 1021-1026 ◽  
Author(s):  
Gilbert Miller ◽  
Ahmad Khalilian ◽  
Jeffrey W. Adelberg ◽  
Hamid J. Farahani ◽  
Richard L. Hassell ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Root Length ◽  
Root Zone ◽  
Root Length Density ◽  
Soil Depth ◽  
Citrullus Lanatus ◽  
Irrigation Management ◽  
Irrigation Treatment ◽  
System Size ◽  
Deep Soil

Delineating the depth and extent of the watermelon [Citrullus lanatus (Thumb.) Matsum. & Nak.] root zone assists with proper irrigation management and minimizes nutrient leaching. The objective of this 3-year field study was to measure root distribution and root length density of watermelon (cv. Wrigley) grafted on two different rootstocks (Lagenaria siceraria cv. ‘FR Strong’ and Cucurbita moschata × Cucurbita maxima cv. Chilsung Shintoza) and grown under three soil moisture treatments. Irrigation treatments tested were: no irrigation (NI), briefly irrigated for fertigation and early-season plant establishment; minimally irrigated (MI), irrigated when soil moisture in top 0.30 m of soil fell below 50% available water capacity (AWC); well irrigated (WI), irrigated when soil moisture in top 0.30 m of soil fell below 15% (AWC). Root length density (RLD) was measured from 75-cm-deep soil cores at two locations three times per growing season and a third location at the end of the season. Cores 1 and 2 sample locations were 15 cm to the side of each plant: Core 1 on the same side as the drip tape and Core 2 on the opposite side. At the end of the season, Core 3 was taken 15 cm outside of the bed in bare ground. RLD was significantly greater in the 0- to 30-cm soil depth and dropped dramatically below 30 cm; it was not significantly affected by irrigation treatment or rootstock. Core 1, next to the drip tape, had greater RLD than Core 2, 30 cm from drip tape, but only at the later sampling dates. Roots were found in Core 3 at all depths, but the RLD was significantly less than that measured in Cores 1 and 2. These findings suggest that the effective root zone depth for watermelon is 0 to 30 cm and that the particular scion/rootstock combinations tested in this study do not differ in root system size or location.

scholarly journals The effects of stemflow on redistributing precipitation and infiltration around shrubs

2018 ◽  
Vol 66 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Shengqi Jian ◽  
Xueli Zhang ◽  
Dong Li ◽  
Deng Wang ◽  
Zening Wu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
Soil Depth ◽  
Rainfall Threshold ◽  
Chinese Loess Plateau ◽  
Wetting Front ◽  
Deep Soil ◽  
Soil Layers ◽  
Chinese Loess ◽  
Caragana Korshinskii

Abstract The experiments of stemflow of two semiarid shrubs (Caragana korshinskii and Hippophae rhamnoides) and its effect on soil water enhancement were conducted from 1st May to 30th September of 2009-2013 in the Chinese Loess Plateau. Stemflow values in C. korshinskii and H. rhamnoides averaged 6.7% and 2.4% of total rainfall. The rainfall threshold for stemflow generation was 0.5 and 2.5 mm for C. korshinskii and H. rhamnoides. When rainfall was less than 17.0 mm, the funnelling ratios were highly variable, however, stable funnelling ratios were found for rainfall greater than 17.0 mm for C. korshinskii. The funnelling ratios of H. rhamnoides first increased until a threshold value of 10.0 mm and then the funnelling ratios begin stabilize. The wetting front depths in the area around stem was 1.4-6.7 and 1.3-2.9 times deeper than area outside the canopy for C. korshinskii and H. rhamnoides. Soil moisture at soil depth 0-200 cm was 25.6% and 23.4% higher in soil around stem than that outside canopy for C. korshinskii and H. rhamnoides. The wetting front advanced to depths of 120 and 100 cm in the area around stem and to depths of 50 cm in the area outside the canopy for C. korshinskii and H. rhamnoides suggested that more rain water can be conserved into the deep soil layers through shrub stemflow. Soil moisture was enhanced in the area outside the shrub canopy, only when rainfall depth is > 4.7 and 5.1 mm, which is an effective rainfall for the area for C. korshinskii and H. rhamnoides. While for the area around stem of C. korshinskii and H. rhamnoides, the corresponding threshold values are 3.2 and 4.3 mm. These results confirmed that stemflow has a positive effect on soil moisture balance of the root zone and the enhancement in soil moisture of deeper soil layers.

Soil moisture assessment based on Sentinel 1/2 and in-situ data: The vineyard case study

2021 ◽  
Author(s):  
Maria Paula Mendes ◽  
Ana Paula Falcão ◽  
Magda Matias ◽  
Rui Gomes
Keyword(s):  
Soil Moisture ◽  
Climate Models ◽  
Root Zone ◽  
Irrigation Management ◽  
Management Strategies ◽  
Winter Period ◽  
Classification Algorithms ◽  
Precipitation Regime ◽  
Terrain Attributes ◽  
Sentinel 2

<p>Vineyards are crops whose production has a major economic impact in the Portuguese economy (~750 million euros) being exported worldwide. As the climate models project a larger variability in precipitation regime, the water requirements of vineyards can change and drip irrigation can be responsible for salt accumulation in the root zone, especially when late autumn and winter precipitation is not enough to leach salts from the soil upper horizons, turning the soil unsuitable for grape production.</p><p>The aim of this work is to present a methodology to map surface soil moisture content (SMC) in a vineyard, (40 hectares) based on the application of two classification algorithms to satellite imagery (Sentinel 1 and Sentinel 2). Two vineyard plots were considered and three field campaigns (December 2017, January 2018 and May 2018) were conducted to measure soil moisture contents (SMC). A geostatistical method was used to estimate the SM class probabilities according to a threshold value, enlarging the training set (i.e., SMC data of the two plots) for the classification algorithms. Sentinel-1 and Sentinel-2 images and terrain attributes fed the classification algorithms. Both methods, Random Forest and Logistic Regression, classified the highest SMC areas, with probabilities above 14%, located close to a stream at the lower altitudes.</p><p>RF performed very well in classifying the topsoil zones with lower SMC during the autumn-winter period (F-measure=0.82).</p><p>This delineation allows the prevention of the occurrence of areas affected by salinization, indicating which areas will need irrigation management strategies to control the salinity, especially under climate change, and the expected increase in droughts.</p>

A regionally explicit, global SWI calibration based on ISMN observations

2021 ◽  
Author(s):  
Manolis G. Grillakis
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Large Scale ◽  
Root Zone ◽  
Soil Depth ◽  
European Space Agency ◽  
Soil Layer ◽  
Added Value ◽  
Water Index ◽  
Soil Moisture Data

<p>Remote sensing has proven to be an irreplaceable tool for monitoring soil moisture. The European Space Agency (ESA), through the Climate Change Initiative (CCI), has provided one of the most substantial contributions in the soil water monitoring, with almost 4 decades of global satellite derived and homogenized soil moisture data for the uppermost soil layer. Yet, due to the inherent limitations of many of the remote sensors, only a limited soil depth can be monitored. To enable the assessment of the deeper soil layer moisture from surface remotely sensed products, the Soil Water Index (SWI) has been established as a convolutive transformation of the surface soil moisture estimation, under the assumption of uniform hydraulic conductivity and the absence of transpiration. The SWI uses a single calibration parameter, the T-value, to modify its response over time.</p><p>Here the Soil Water Index (SWI) is calibrated using ESA CCI soil moisture against in situ observations from the International Soil Moisture Network and then use Artificial Neural Networks (ANNs) to find the best physical soil, climate, and vegetation descriptors at a global scale to regionalize the calibration of the T-value. The calibration is then used to assess a root zone related soil moisture for the period 2001 – 2018.</p><p>The results are compared against the European Centre for Medium-Range Weather Forecasts, ERA5 Land reanalysis soil moisture dataset, showing a good agreement, mainly over mid-latitudes. The results indicate that there is added value to the results of the machine learning calibration, comparing to the uniform T-value. This work contributes to the exploitation of ESA CCI soil moisture data, while the produced data can support large scale soil moisture related studies.</p>

Root and Shoot Responses to Salt Stress in Jojoba (Simmondsia chinensis)

2020 ◽  
Author(s):  
Jhonathan Ephrath ◽  
Alon Ben-Gal ◽  
Amnon Bustan ◽  
Lina Zhao
Keyword(s):  
Plant Growth ◽  
Root Length ◽  
Root Length Density ◽  
Soil Depth ◽  
Distribution Patterns ◽  
Root Diameter ◽  
Salinity Level ◽  
Simmondsia Chinensis ◽  
Root Number ◽  
Over Time

<p>Salinity affects plant growth due to both osmotic and ionic stress. The root system is essential in defense mechanisms against salinity, particularly involving salt ion avoidance or exclusion. Jojoba (<em>Simmondsia chinensis</em>) displays significant resistance to salinity. In the present study, Jojoba was planted in 60-L plastic buckets containing perlite growth medium and were provided with eight distinct salinity levels using two operating tanks of final irrigation solutions. Response of Jojoba to salinity was measured in above ground parameters and in roots using minirhizotron access tubes and imaging analysis. Leaf phosphorous and potassium concentrations decreased with increasing salinity level while leaf manganese, calcium, sodium and chloride concentrations increased with irrigation salinity level. Jojoba plants were found to have high level of storage of salt minerals in leaves but without effects on photosynthesis or transpiration. Roots exhibited different distribution patterns under different salinity treatments. Root length density increased with increased salinity at each depth. Root number and root length increased over time. During spring, the plant growth was faster than winter. Root diameter decreased over time due to new root development. Time had a more significant effect on root length density than irrigation water salinity or soil depth. Root number and root length were not significantly affected by the salt treatments.</p>

What limits deep water uptake by deep-rooted crops?

2020 ◽  
Author(s):  
Camilla Rasmussen ◽  
Eva Rosenqvist ◽  
Fulai Liu ◽  
Dorte Bodin Dresbøll ◽  
Kristian Thorup-Kristensen ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Water Uptake ◽  
Deep Water ◽  
Large Scale ◽  
Root Zone ◽  
Root Length Density ◽  
Yield Losses ◽  
Deep Soil ◽  
Deep Roots ◽  
Water Limitations

<p>Minimizing water limitation during growth of agricultural crops is crucial to unlocking full yield potentials. Crop yield losses vary according to timing and severity of water limitations, but even short-term droughts can be a major cause of yield losses. While the potential influence of deep roots on water uptake has been highlighted numerous times, the actual contribution of deep roots to water uptake is yet to be revealed. The objective of this study is to get an understanding of what limits deep water uptake by deep-rooted crops under topsoil water limitations.</p><p>We found that deep-rooted crops experience water limitations despite access to water stored in the deep soil and we hypothesize that deep water uptake by deep-rooted crops is limited by 1) the hydraulic conductivity of the deeper part of the root zone, arising from limited root length density in combination with the hydraulic resistance of the roots or 2) by a hormonal response arising from the plant sensing dry conditions in the shallow soil leading to stomata closure, to conserve water. The two hypotheses can of course not be valid simultaneously, but both might be valid under certain conditions, at certain times or for certain species.</p><p>In a large-scale semi-field setup, we grow oil seed rape and by combining measures of root development, root hydraulic conductivity, transpiration, stomatal conductance, ABA concentrations and soil water content from a large scale semi-field setup with a mechanistic 3-D root-soil modelling approach (R-SWMS), we are able to us distinguish various scenarios and to evaluate what limits deep water uptake.</p>

Root length density and soil water distribution in drip-irrigated olive orchards in Argentina under arid conditions

2009 ◽  
Vol 60 (3) ◽  
pp. 280 ◽  
Author(s):  
Peter S. Searles ◽  
Diego A. Saravia ◽  
M. Cecilia Rousseaux
Keyword(s):  
Water Content ◽  
Root System ◽  
Soil Water ◽  
Soil Water Content ◽  
Root Length ◽  
Root Length Density ◽  
Soil Depth ◽  
Drip Line ◽  
North West ◽  
Intensively Managed

Several studies have evaluated many above-ground aspects of olive production, but essential root system characteristics have been little examined. The objective of our study was to evaluate root length density (RLD) and root distribution relative to soil water content in three commercial orchards (north-west Argentina). Depending on the orchard, the different drip emitter arrangements included either: (1) emitters spaced continuously at 1-m intervals along the drip line (CE-4; 4 emitters per tree); (2) 4 emitters per tree spaced at 1-m intervals, but with a space of 2 m between emitters of neighbouring trees (E-4); or (3) 2 emitters per tree with 4 m between emitters of neighbouring trees (E-2). All of the orchards included either var. Manzanilla fina or Manzanilla reina trees (5–8 years old) growing in sandy soils, although the specific characteristics of each orchard differed. Root length density values (2.5–3.5 cm/cm3) in the upper soil depth (0–0.5 m) were fairly uniform along the drip line in the continuous emitter (CE-4) orchard. In contrast, roots were more concentrated in the E-4 and E-2 orchards, in some cases with maximum RLD values of up to 7 cm/cm3. Approximately 70% of the root system was located in the upper 0.5 m of soil depth, and most of the roots were within 0.5 m of the drip line. For each of the three orchards, significant linear relationships between soil water content and RLD were detected based on 42 sampling positions that included various distances from the trunk and soil depths. Values of RLD averaged over the entire rooting zone and total tree root length per leaf area for the three orchards were estimated to range from 0.19 to 0.48 cm/cm3 and from 1.8 to 3.5 km/m2, respectively. These results should reduce the uncertainty associated with the magnitude of RLD values under drip irrigation as intensively managed olive orchards continue to expand in established and new growing regions.

Root length density and water uptake in cereals and grain legumes: how well are they correlated

1987 ◽  
Vol 38 (3) ◽  
pp. 513 ◽  
Author(s):  
AP Hamblin ◽  
D Tennant
Keyword(s):  
Water Uptake ◽  
Root Length ◽  
Root Zone ◽  
Root Length Density ◽  
Genotypic Variation ◽  
Root Water Uptake ◽  
Grain Legumes ◽  
Rooting Depth ◽  
Rates Of Change ◽  
Axial Resistance

Total root length per unit ground area (La) is often considered to be directly related to the amount and rate of water uptake. Experiments were conducted to compare the water use of spring wheat, barley, lupin (L. angustifolius) and field pea on four differing soil types in drought-stressed conditions. The La values of cereals were consistently five to ten times as large as those of grain legumes, whereas the aboveground biomass was sim~iar and never greater than twice that of the grain legumes. Growing-season water loss (WL) from the soil profile was very similar for wheat and lupins, despite this big difference in root length. Soil evaporation may have been greater under lupins, but when crop water uptake was compared for the period when leaf area was greatest, rates of change in soil water content within the root zone were still similar and were not well correlated with La. Specific root water uptake (Ur) was consistently greater for lupin than wheat. Maximum rooting depth was better correlated with WL than was La in all cases. Higher Ur values in lupin and pea may be related to their large and abundant metaxylem vessels, which give much lower axial resistance than in cereals. These results provide strong evidence for genotypic variation in root morphology, density and root extension between dicotyledenous and monocotyledenous species. They also indicate that La is not necessarily the root morphological characteristic most responsible for efficiency of water uptake in drought-stressed environments.

scholarly journals A global analysis of satellite derived and DGVM surface soil moisture products

2011 ◽  
Vol 8 (2) ◽  
pp. 4281-4312
Author(s):  
K. T. Rebel ◽  
R. A. M. de Jeu ◽  
P. Ciais ◽  
N. Viovy ◽  
S. L. Piao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Root Zone ◽  
Global Analysis ◽  
Single Layer ◽  
Global Scale ◽  
Rain Event ◽  
Deep Soil ◽  
Surface Climate ◽  
Soil Moisture Availability

Abstract. Soil moisture availability is important in regulating photosynthesis and controlling land surface-climate feedbacks at both the local and global scale. Recently, global remote-sensing datasets for soil moisture have become available. In this paper we assess the possibility of using remotely sensed soil moisture (AMSR-E) to evaluate the results of the process-based vegetation model ORCHIDEE during the period 2003–2004. We find that the soil moisture products of AMSR-E and ORCHIDEE correlate well, in particular when considering the root zone soil moisture of ORCHIDEE. However, the root zone soil moisture in ORCHIDEE consistently overestimated the temporal autocorrelation relative to AMSR-E and in situ measurements. This may be due to the different vertical depth of the two products, to the uncertainty in precipitation forcing in ORCHIDEE, and to the fact that the structure of ORCHIDEE consisting of a single-layer deep soil, does not allow simulation of the proper cascade of time scales that characterize soil drying after each rain event. We conclude that assimilating soil moisture in ORCHIDEE using AMSR-E with the current hydrological model may significantly improve the soil moisture dynamics in ORCHIDEE.

scholarly journals Root Distribution and Yield of Direct Seeded and Transplanted Watermelon

1999 ◽  
Vol 124 (5) ◽  
pp. 458-461 ◽  
Author(s):  
D.S. NeSmith
Keyword(s):  
Root Length ◽  
Root Distribution ◽  
Root Length Density ◽  
Citrullus Lanatus ◽  
Growing Season ◽  
Soil Cores ◽  
Marketable Yield ◽  
Stand Establishment ◽  
Planting Methods ◽  
Direct Seeded

Transplanting generally results in more rapid stand establishment than direct seeding for cucurbit crops. A 2-year field study was conducted to examine the pattern of rooting of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nak.] following usage of different planting methods, and to determine subsequent effects on crop yield. Root length was assessed by obtaining soil cores three times per growing season to a depth of 75 cm. Transplanted watermelons generally had greater root length density in the upper 30 cm of soil 4 to 7 weeks after planting (WAP). However, by 11 to 12 WAP root distribution was similar over the entire 75 cm soil profile for the two planting methods. Total marketable yields were comparable for direct seeded and transplanted watermelons during 1995, but transplanted watermelon yield exceeded direct seeded yield by 40% in 1996. In both years, 90% to 100% of the marketable yield of transplanted watermelons was obtained at the first harvest, compared to 0% to 55% for direct seeded watermelons. These findings suggest that rapid root proliferation of transplanted watermelons may be an important factor in their earlier establishment and increased early yields as compared to direct seeded watermelons.

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