scholarly journals Soil water potential effects on the cellulase activities of soil treated with sewage sludge

2010 ◽  
Vol 56 (No. 7) ◽  
pp. 333-339 ◽  
Author(s):  
A.A.S. Sinegani ◽  
A. Mahohi
Keyword(s):  
Sewage Sludge ◽  
Water Potential ◽  
Soil Water ◽  
Irrigation Treatment ◽  
Soil Water Potential ◽  
Field Capacity ◽  
Soil Incubation ◽  
Organic C ◽  
Bacteria And Fungi ◽  
Wilting Point

To better understand how water stress and availability affect the enzyme activity and microbial communities in soil, we measured the changes of organic carbon (OC), bacteria and fungi populations, and endoglucanase and exoglucanase activities in a semiarid soil treated with air-dried primary sewage sludge at a rate of 20 g/kg. The water potentials established for soil incubation were: saturation (SA, 0 bar), field capacity (FC, –0.3 bar), and permanent wilting point (PWP, –15 bar). An irrigation treatment was a drying-rewetting cycle (DWC) between –0.3 to –15 bars. After 0, 20, 60 and 90 days of incubation soils were sampled for analysis. The addition of sewage sludge increased soil OC, endoglucanase and exoglucanase activities significantly. The effects of soil moisture, incubation time and their interactions on OC, and endoglucanase and exoglucanase activities in soil were significant. During 20 days of incubation, OC, endoglucanase and exoglucanase activities decreased significantly. Soils incubated in DWC and FC compared to soils incubated in SA and PWP had lower OC contents due to organic matter mineralization. Organic C, exoglucanase and endoglucanase activities significantly increased with increasing soil water potential. The activities of exoglucanase and endoglucanase in soils incubated in SA were significantly higher than those in soils incubated in PWP.

scholarly journals Soil water potential during different phenological phases of coffee irrigated by center pivot

2013 ◽  
Vol 33 (2) ◽  
pp. 269-278 ◽  
Author(s):  
Adão W. P. Evangelista ◽  
Luiz A. Lima ◽  
Antônio C. da Silva ◽  
Carla de P. Martins ◽  
Moisés S. Ribeiro
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Irrigation Management ◽  
Soil Water Potential ◽  
Field Capacity ◽  
Limiting Factor ◽  
Center Pivot ◽  
Phenological Phases

Irrigation management can be established, considering the soil water potential, as the limiting factor for plant growth, assuming the soil water content between the field capacity and the permanent wilting point as available water for crops. Thus, the aim of this study was to establish the soil water potential interval during four different phenological phases of coffee irrigated by center pivot. The experiment was set at the experimental area of the Engineering Department at the Federal University of Lavras, in Brazil. The coffee variety planted is designated as Rubi, planted 0.8 meters apart, with rows spaced 3.5 meters apart. The treatments corresponded to the water depths applied based on different percentages of Kc and reference evapotranspiration (ET0) values. Sensors were used to measure the soil water potential interval, installed 25 centimeters depth. In order to compare the results, it was considered as the best matric potential the one that was balanced with the soil water content that resulted in the largest coffee productivity. Based on the obtained results, we verified that in the phases of fruit expansion and ripening, the best results were obtained, before the irrigations, when the soil water potential values reached -35 and -38 kPa, respectively. And in the flowering, small green and fruit expansion phases, when the values reached -31 and -32 kPa, respectively.

scholarly journals Germination of Acacia harpophylla (Brigalow) seeds in relation to soil water potential: Implications for rehabilitation of a threatened ecosystem

2013 ◽  
Author(s):  
Sven Arnold ◽  
Yolana Kailichova ◽  
Thomas Baumgartl
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Saturation ◽  
Critical Role ◽  
Soil Water Potential ◽  
Field Capacity ◽  
Environmental Stressor ◽  
Mining Areas ◽  
Eastern Australia ◽  
Hydrotime Model

Initial soil water conditions play a critical role when seeding is the primary approach of revegetation on post-mining areas. In some semi-arid climates, such as the Brigalow Belt Bioregion in eastern Australia, extensive areas are affected by surface mine developments. Together with erratic rainfall patterns and clayey soils water deficit is the primary environmental stressor, which makes the Brigalow Belt representative for other water-limited ecosystems worldwide. Apart from other environmental stressors germination is governed by the water potential of the surrounding soil material. While previous studies confirmed the high tolerance of Brigalow (Acacia harpophylla) seeds to a broad range of temperature and salinity, the question remains how soil water potential triggers seed germination. In this study, we used three replicates of 50 seeds of predominant native Brigalow to investigate germination in relation to water potential as environmental stressor. Solutions of Polyethylene Glycol (PEG 6000) were applied to expose seeds to nine osmotic water potentials ranging from soil water saturation (0 kPa) and field capacity (-10 to -30 kPa) to the permanent wilting point (-1,500 kPa). We measured germinability (number of germinated seeds relative to total number of seeds per lot) and mean germination time (mean time required for maximum germination of a seed lot) to quantify germination. Based on these empirical data we estimated the parameters of the hydrotime model, which facilitates to simulate timing and success of seed emergence. Our findings indicate that Brigalow seeds are remarkably water stress tolerant with germination being observed at a water potential as low as -1,500 kPa. Likewise, the average base water potential of a seed population (hydrotime model) was very low and ranged between -1,533 kPa and -1,451 kPa. In general, Brigalow seeds germinate opportunistically over a broad range of abiotic conditions related to temperature, salinity, and water availability. Direct seeding and germination of native plants on post-mining land may be an effective and economically viable solution in order to re-establish plant communities. However, due to their ability of asexual reproduction, alternative rehabilitation approaches such as transplantation of whole soil-root compartments may become attractive for restoration ecologists to achieve safe, stable, and non-polluting ecosystems.

scholarly journals Germination of Acacia harpophylla (Brigalow) seeds in relation to soil water potential: Implications for rehabilitation of a threatened ecosystem

2013 ◽  
Author(s):  
Sven Arnold ◽  
Yolana Kailichova ◽  
Thomas Baumgartl
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Saturation ◽  
Critical Role ◽  
Soil Water Potential ◽  
Field Capacity ◽  
Environmental Stressor ◽  
Mining Areas ◽  
Eastern Australia ◽  
Hydrotime Model

Initial soil water conditions play a critical role when seeding is the primary approach of revegetation on post-mining areas. In some semi-arid climates, such as the Brigalow Belt Bioregion in eastern Australia, extensive areas are affected by surface mine developments. Together with erratic rainfall patterns and clayey soils water deficit is the primary environmental stressor, which makes the Brigalow Belt representative for other water-limited ecosystems worldwide. Apart from other environmental stressors germination is governed by the water potential of the surrounding soil material. While previous studies confirmed the high tolerance of Brigalow (Acacia harpophylla) seeds to a broad range of temperature and salinity, the question remains how soil water potential triggers seed germination. In this study, we used three replicates of 50 seeds of predominant native Brigalow to investigate germination in relation to water potential as environmental stressor. Solutions of Polyethylene Glycol (PEG 6000) were applied to expose seeds to nine osmotic water potentials ranging from soil water saturation (0 kPa) and field capacity (-10 to -30 kPa) to the permanent wilting point (-1,500 kPa). We measured germinability (number of germinated seeds relative to total number of seeds per lot) and mean germination time (mean time required for maximum germination of a seed lot) to quantify germination. Based on these empirical data we estimated the parameters of the hydrotime model, which facilitates to simulate timing and success of seed emergence. Our findings indicate that Brigalow seeds are remarkably water stress tolerant with germination being observed at a water potential as low as -1,500 kPa. Likewise, the average base water potential of a seed population (hydrotime model) was very low and ranged between -1,533 kPa and -1,451 kPa. In general, Brigalow seeds germinate opportunistically over a broad range of abiotic conditions related to temperature, salinity, and water availability. Direct seeding and germination of native plants on post-mining land may be an effective and economically viable solution in order to re-establish plant communities. However, due to their ability of asexual reproduction, alternative rehabilitation approaches such as transplantation of whole soil-root compartments may become attractive for restoration ecologists to achieve safe, stable, and non-polluting ecosystems.

scholarly journals Response of Buttonwood (Conocarpus erectus) Trees to Drought Conditions

2007 ◽  
Vol 12 ◽  
pp. 21
Author(s):  
Ansary Edris Moftah ◽  
Abdul-Rahman Ibrahim AL-Humaid
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Osmotic Adjustment ◽  
Soluble Sugars ◽  
Soil Water Potential ◽  
Extended Period ◽  
Field Capacity ◽  
Resistant Species ◽  
Conocarpus Erectus

Six-month-old buttonwood (Conocarpus erectus L.) seedlings were grown in containers under different soil water potentials (Ψsoil). The objective of the work was: 1) to determine the minimum soil water potential at which Conocarpus trees can survive and grow fairly well, 2) to study the soil-plant water relationship at different irrigation regimes, and 3) to examine the capacity of Conocarpus seedlings for osmotic adjustment via solute accumulation. Seedling growth was not affected significantly at soil water potential above –0.1 MPa (between 40 and 30% Field Capacity (FC). At lowerΨsoil, plant height, leaf area and shoot and root dry weights became disrupted by water deficit. Water stress decreased the osmotic potential (Ψπ) of leaves and roots. Leaves tended to osmoregulate their cell sap through osmotic adjustment processes as their content of soluble sugars increased. The positive survival under low Ψsoil could be related to increased osmotic adjustment. Ψsoil values were found to be more useful than FC values to estimate water requirements and use over an extended period of time, for plants grown under different soil types and different environmental conditions. Conocarpus seedlings can withstand reasonable water stress and can survive at moderately low water potential but, in contrast to other studies, this can not be classified as a high drought tolerant or resistant species. 

scholarly journals Evaluation of different soil water potential by field capacity threshold in combination with a triggered irrigation module

2016 ◽  
Vol 10 (No. 3) ◽  
pp. 164-171 ◽  
Author(s):  
M. Marković ◽  
V. Filipović ◽  
T. Legović ◽  
M. Josipović ◽  
V. Tadić
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Field Capacity

Effect of Soil Water Potential of Two Soils on Soybean Emergence 1

1979 ◽  
Vol 71 (6) ◽  
pp. 980-982 ◽  
Author(s):  
L. G. Heatherly ◽  
W. J. Russell
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential

scholarly journals A Data-Driven Method for the Temporal Estimation of Soil Water Potential and Its Application for Shallow Landslides Prediction

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1208
Author(s):  
Massimiliano Bordoni ◽  
Fabrizio Inzaghi ◽  
Valerio Vivaldi ◽  
Roberto Valentino ◽  
Marco Bittelli ◽  
...  
Keyword(s):  
Machine Learning ◽  
Water Potential ◽  
Soil Water ◽  
Temporal Trends ◽  
Soil Water Potential ◽  
Shallow Landslides ◽  
Water Dynamics ◽  
Data Driven ◽  
Machine Learning Techniques ◽  
Physically Based

Soil water potential is a key factor to study water dynamics in soil and for estimating the occurrence of natural hazards, as landslides. This parameter can be measured in field or estimated through physically-based models, limited by the availability of effective input soil properties and preliminary calibrations. Data-driven models, based on machine learning techniques, could overcome these gaps. The aim of this paper is then to develop an innovative machine learning methodology to assess soil water potential trends and to implement them in models to predict shallow landslides. Monitoring data since 2012 from test-sites slopes in Oltrepò Pavese (northern Italy) were used to build the models. Within the tested techniques, Random Forest models allowed an outstanding reconstruction of measured soil water potential temporal trends. Each model is sensitive to meteorological and hydrological characteristics according to soil depths and features. Reliability of the proposed models was confirmed by correct estimation of days when shallow landslides were triggered in the study areas in December 2020, after implementing the modeled trends on a slope stability model, and by the correct choice of physically-based rainfall thresholds. These results confirm the potential application of the developed methodology to estimate hydrological scenarios that could be used for decision-making purposes.

NITROGEN TRANSFORMATIONS NEAR UREA IN SOIL WITH DIFFERENT WATER POTENTIALS

1988 ◽  
Vol 68 (3) ◽  
pp. 569-576 ◽  
Author(s):  
YADVINDER SINGH ◽  
E. G. BEAUCHAMP
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Incubation Period ◽  
Relative Rate ◽  
Soil Water Potential ◽  
Nitrification Inhibitor ◽  
Silt Loam ◽  
Nitrogen Transformations ◽  
Water Potentials ◽  
Initial Soil

Two laboratory incubation experiments were conducted to determine the effect of initial soil water potential on the transformation of urea in large granules to nitrite and nitrate. In the first experiment two soils varying in initial soil water potentials (− 70 and − 140 kPa) were incubated with 2 g urea granules with and without a nitrification inhibitor (dicyandiamide) at 15 °C for 35 d. Only a trace of [Formula: see text] accumulated in a Brookston clay (pH 6.0) during the transformation of urea in 2 g granules. Accumulation of [Formula: see text] was also small (4–6 μg N g−1) in Conestogo silt loam (pH 7.6). Incorporation of dicyandiamide (DCD) into the urea granule at 50 g kg−1 urea significantly reduced the accumulation of [Formula: see text] in this soil. The relative rate of nitrification in the absence of DCD at −140 kPa water potential was 63.5% of that at −70 kPa (average of two soils). DCD reduced the nitrification of urea in 2 g granules by 85% during the 35-d period. In the second experiment a uniform layer of 2 g urea was placed in the center of 20-cm-long cores of Conestogo silt loam with three initial water potentials (−35, −60 and −120 kPa) and the soil was incubated at 15 °C for 45 d. The rate of urea hydrolysis was lowest at −120 kPa and greatest at −35 kPa. Soil pH in the vicinity of the urea layer increased from 7.6 to 9.1 and [Formula: see text] concentration was greater than 3000 μg g−1 soil. There were no significant differences in pH or [Formula: see text] concentration with the three soil water potential treatments at the 10th day of the incubation period. But, in the latter part of the incubation period, pH and [Formula: see text] concentration decreased with increasing soil water potential due to a higher rate of nitrification. Diffusion of various N species including [Formula: see text] was probably greater with the highest water potential treatment. Only small quantities of [Formula: see text] accumulated during nitrification of urea – N. Nitrification of urea increased with increasing water potential. After 35 d of incubation, 19.3, 15.4 and 8.9% of the applied urea had apparently nitrified at −35, −60 and −120 kPa, respectively. Nitrifier activity was completely inhibited in the 0- to 2-cm zone near the urea layer for 35 days. Nitrifier activity increased from an initial level of 8.5 to 73 μg [Formula: see text] in the 3- to 7-cm zone over the 35-d period. Nitrifier activity also increased with increasing soil water potential. Key words: Urea transformation, nitrification, water potential, large granules, nitrifier activity, [Formula: see text] production

Sign in / Sign up

Export Citation Format

Share Document