Revisiting the wet and dry ends of soil integral water capacity using soil and plant properties

Soil Research ◽  
2018 ◽  
Vol 56 (4) ◽  
pp. 331 ◽  
Author(s):  
Fatemeh Meskini-Vishkaee ◽  
Mohammad Hossein Mohammadi ◽  
Mohammad Reza Neyshabouri

The integral water capacity (IWC) approach takes into account various soil physical limitations for calculating plant available water. However, the IWC approach cannot distinguish the differences in water uptake between various plants. Therefore, the objectives of this study were i) to modify the approach to include plant physiological properties to redefine the wet and dry ends of the IWC, called IWCplant and ii) to evaluate the performance of the IWCplant approach using experimental data. The restrictions imposed by poor soil aeration and rapid drainage flux were calculated using both soil and plant properties to modify the wet end of the IWC. The soil hydraulic resistance was considered to redefine the dry end of the IWCplant. Based on these approaches, physically meaningful weighting functions were developed for three proposed limiting factors at both ends of the wet and dry ranges of soil. Experimental data were obtained from a greenhouse trial with wheat and canola plants in two soil textures (sandy loam and clay loam) for 2 years. The IWCplant obtained values of 0.202 and 0.205 m3 m–3 for wheat and 0.189 and 0.194 m3 m–3 for canola in sandy loam and clay loam soils, respectively. These differences in the IWCplant between wheat and canola in the same soils demonstrate the importance of plant properties to estimate actual plant available water using IWC. These differences would be even more appreciable for root systems with a wider range of different properties.

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 577 ◽  
Author(s):  
P. H. Groenevelt ◽  
C. D. Grant ◽  
S. Semetsa

The integral water capacity is first introduced as a flexible method to quantify various soil physical limitations when calculating available water in non-swelling soils. ‘Weighting’ functions that account for hydraulic conductivity, aeration, and soil resistance to penetration are applied to the wet and dry ends of the differential water capacity, and then integration is performed. The concept is extended to swelling soils by applying the theory of Groenevelt and Bolt (1972), which enables overburden pressures to be taken into account. A set of shrinkage lines measured by Talsma (1977) is analysed using this theory, which enables precise values of overburden potentials to be calculated as a function of the moisture ratio for different load pressures. The addition of the overburden potential to the unloaded matric potential causes minor shifts in the classical limits of plant-available water (viz. –1/3 bar and –15 bar). However, when other soil physical restrictions are taken into account (such as in the concept of the least limiting water range), the consequence for available water deeper in the root-zone (due to an overburden pressure) is far more serious. This is primarily because the matric potential at which aeration begins to be satisfied shifts to a considerably lower value, making a large quantity of water at the wet end no longer available. Examples of weighting functions derived from the literature are applied and their implications for available water in swelling soils are discussed.


Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2005
Author(s):  
Jacek Długosz ◽  
Anna Piotrowska-Długosz ◽  
Karol Kotwica ◽  
Ewelina Przybyszewska

The application of various conditioners in agriculture is one of the management practices used to improve soil quality and plant growth and development. The aim of this study was to assess the effect of a multi-component conditioner on the selected soil properties and maize (Zea mays L.) growth and yield. The effect of a conditioner on a set of soil properties and maize growth and yield was studied in one-year experiments carried out at three study sites, which were under a conventional tillage system. All of the study sites were located on farms in three geographic mezoregions in the Kuyavian-Pomeranian Region (Midwestern Poland). The studied soils were Haplic Luvisol (Janocin and Kobylnica) and Albic Luvisols (Krukówko) that were composed of sandy loam. A one-way analysis of variance (ANOVA) was used to determine the effect of a conditioner Solactiv on the soil and plant properties. The conditioner significantly affected the soil enzyme activities such as dehydrogenase (DHA), fluorescein sodium salt hydrolysis level (FDAH) and carboxymethylcellulose cellulase (CMC—cellulase); wherein the last one increased by about 16–20%. The application of Solactiv also increased the available K content (about 11%) but not the content of the microbial biomass C and N. Total porosity (TP), which was significantly higher in the soil treated with conditioner than in the control soils, increased the available water capacity (AWC) (about 2.2%). The higher AWC in the treated soil indicated the greater contribution of the mesopores in the TP (about 4%). A significantly higher readily available water capacity (RAWC) and small pores available water capacity (SAWC) was determined in the treated soils compared to the controls. Of the plant properties, only plant height, fresh cob biomass (BBCH 87–89) and fresh plant biomass (BBCH 84–85) were significantly increased by the conditioner. The application of Solactiv is considered to be a promising approach for developing sustainable agriculture by improving the soil’s biological activity and water-related properties.


2007 ◽  
Vol 71 (6) ◽  
pp. 1902-1908 ◽  
Author(s):  
Pingping Jiang ◽  
Stephen H. Anderson ◽  
Newell R. Kitchen ◽  
Kenneth A. Sudduth ◽  
E. John Sadler

Soil Research ◽  
1981 ◽  
Vol 19 (3) ◽  
pp. 197 ◽  
Author(s):  
JA Mullins

The plant available water capacity (PAWC) was measured for a range of soils (black earths, grey, brown and red clays, krainozems, yellow earths and solodized solonetz/solodics) used for dryland agriculture in the uplands of th,- eastern Darling Downs of Queensland. Using these data, two one-parameter models - one based on the electrical conductivity profile and the other on observable profile features - were derived for estimating the PAWC of the soil profile. The electrical conductivity profile model reliably estimated the PAWC for black earths and grey, brown and red clays. In the case of the deep, black earths, it accounted for 90% of the variation. The observable profile feature model reliably estimated the PAWC for black earths and grey, brown and red clays and in the case of the grey, brown and red clays accounted for 88% of the variation. The models for the solodized solonetz/solodics were not significant. In addition the profile feature model provided estimates of PAWC for the krasnozems (grouped with black earths) and for the yellow earths and solodized solonetz/solodics as a group. An alternative technique for the estimation of PAWC for krasnozems and yellow earths is also presented. The techniques will provide a rapid first appraisal of the PAWC of a soil profile.


2009 ◽  
Vol 60 (9) ◽  
pp. 885 ◽  
Author(s):  
M. A. Rab ◽  
P. D. Fisher ◽  
R. D. Armstrong ◽  
M. Abuzar ◽  
N. J. Robinson ◽  
...  

Spatial variability in grain yield can arise from variation in many different soil and terrain properties. Identification of important sources of variation that bear significant relationship with grain yield can help achieve more effective site-specific management. This study had three aims: (i) a geostatistical description/modelling of the paddock-level spatial structure in variability of plant-available water capacity (PAWC) and related soil properties, (ii) to determine optimal number of management zones in the paddock, and (iii) to assess if the variability in PAWC and related soil properties is significantly associated with the variability in grain yield across the management zones. Particle size distribution, bulk density (BD), field capacity (FC), permanent wilting point (PWP), and soil water content (SWC) at sowing were measured at 4 soil depths (to 0.60 m) at 50 representative spatial sampling locations across a paddock near Birchip (Victoria). PAWC and plant-available water at sowing (PAWs) were derived from these data. Moderate to strong spatial dependence across the paddock was observed. The magnitude of the structural variation and of range varied widely across different soil properties and depths. The south-east edge and the central areas of the paddock had higher clay content, FC, PWP, PAWC, and lower PAWs. The paddock was divided into 6 potential management zones using combined header yield and normalised difference vegetation index (NDVI). The adequacy of zoning was evaluated using relative variability (RV) of header yield and soil properties. The mean RV for 3 zones differed little from that of 6 management zones for header yield and for each measured soil property, indicating division of the paddock into 3 zones to be adequate. The results from residual maximum likelihood (ReML) analysis showed that low yield zones had significantly higher clay content, FC, PWP, SWC, and PAWC and significantly lower PAWs than both medium and high yield zones. The mean FC, PWP, and PAWC in the low yield zones were, respectively, 25%, 26%, and 28% higher, and PAWs 36% lower than their corresponding values in the high yield zones. Linear regression analysis indicated that 59–96% of the observed variation in grain yield across management zones could be explained by variation in PWP. The practical implications of these results are discussed.


Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 939-952 ◽  
Author(s):  
M. T. de Melo Carvalho ◽  
A. de Holanda Nunes Maia ◽  
B. E. Madari ◽  
L. Bastiaans ◽  
P. A. J. van Oort ◽  
...  

Abstract. The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 Mg ha−1) on the water retention capacity (WRC) of a sandy loam Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g−1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields 2 and 3 years after its application. Undisturbed soil samples were collected from 16 plots in two soil layers (5–10 and 15–20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant-available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each Mg ha−1 biochar amendment 2 and 3 years after its application. The impact of biochar on soil WRC was most likely related to an effect in overall porosity of the sandy loam soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5 and 1.6% for each Mg ha−1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during the critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under short-term water-limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.


2019 ◽  
Vol 212 ◽  
pp. 441-447 ◽  
Author(s):  
Renye Wu ◽  
Roger Lawes ◽  
Yvette Oliver ◽  
Andrew Fletcher ◽  
Chao Chen

Author(s):  
Vicente Pinto Simões ◽  
Eduardo Souza ◽  
Mauricio Luiz Leite ◽  
Rodolfo Souza ◽  
José Raliuson Silva ◽  
...  

Soil degradation imposes significant environmental and economic impacts on the pastures of drylands worldwide, making livestock grazing systems often unsustainable under the present climate conditions. In this study, we aimed to compare the attributes of the soil of different grazing areas (pastures) using sensitive indicators of changes in the management of these areas, such as the physical-hydric properties and the CO efflux (ECO) from the soil. The study was carried out in three areas of exclosure grazing, understood by three land uses: a pasture of sabi grass (LU1), a silvopastoral system with sabi grass and tree legume (LU2), and an area with sabi grass and a herbaceous native legume (LU3). The measurements were undertaken over nine months and then grouped into three seasons (dry, transition, and rainy). The ECO and the ten indicators of soil physical-hydric quality were measured: macroporosity, aeration capacity, plant-available water capacity (PAWC), relative field capacity (RFC), characteristic pore radius, quantity of hydraulically active pores, sorptivity, saturated hydraulic conductivity, soil density, and soil resistance to penetration. The soils in the LU1 and LU3 areas showed limited plant available water capacity (0.10 PAWC < 0.15 cm cm) and was soil water-limited (RFC < 0.6). The advantages of using silvopastoral systems in semi-arid environments for environmental sustainability are not limited to improvements in the properties of soils, as these areas are also important carbon sinks.


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