scholarly journals Nitrogen Mineralization Modeling in Some Upland Soils in the Western Region of Thailand

2015 ◽  
Vol 9 (11) ◽  
pp. 235
Author(s):  
Busarin Swanglap ◽  
Chawalit Hongprayoon ◽  
Sunchai Phungern
Keyword(s):  
Mathematical Model ◽  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Soil Water Content ◽  
Soil Moisture Content ◽  
Plant Residue ◽  
Organic N ◽  
Western Region ◽  
Mineral N

<p>A laboratory aerobic incubation experiment was conducted to assess the influence of plant residue, soil moisture content, and soil types on mineralization of organic N. The experimental design was a 2 x 3 x 5, factorial arrangement in a Randomized Complete Block design (RCBD) with three replications. The three factors were namely ;(1) two levels of plant residue (0 and 4 ton/rai of grinded cassava shoot), (2) three levels of soil moisture (PWP, ½ AWCA, and FC), and (3) Five upland soil series of the Western region of Thailand, consisting of three main soil textures (fine, medium, and coarse texture). Nitrogen mineralized from native and added organic matter was examined at specific time intervals for 1 year. The data was fitted to a logistic mathematical model describing the relation between mineral N versus moisture content (?), level of plant residue (PR), and time (t). The model was verified by predicting the amount of mineral N released under a given condition and the result was compared to the observed value under the same condition. Application of the model for field condition where soil moisture fluctuates was performed by differentiating the original model to obtain the relation between rate of mineral N production versus N (t), which was the implicit function of ?, PR, and t. Stepwise calculation of the cumulative mineral N with time was developed to predict the amount of N mineralized through time. The results revealed that addition of 4 ton/rai plant residue drastically increased mineral N by 3.6 folds. The effect of soil moisture content and mineralization of organic N confirmed the significance of water on microbial activities. A satisfactory result was obtained from the mathematical model verification. The b and R<sup>2</sup> values were close to 1.0 and the t-test were non-significant. A rather high value of RMSE was obtained contributing to the cycles of microbial population fluctuation. Application of the model to the condition of fluctuating soil water content was performed and compared to the observation value at a given level of plant residue application and soil water content.</p>

Physiological and biochemical responses of Festuca sinensis seedlings to temperature and soil moisture stress

2017 ◽  
Vol 44 (10) ◽  
pp. 1007
Author(s):  
Jian-Jun Wang ◽  
Wei-Hu Lin ◽  
Yan-Ting Zhao ◽  
Cheng Meng ◽  
An-Wei Ma ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Moisture Content ◽  
Soluble Sugar ◽  
Free Proline ◽  
Relative Water ◽  
Physiological And Biochemical

The interaction effects between temperature and soil moisture on Festuca sinensis Keng ex E.B.Alexeev were analysed to determine how F. sinensis responds to these environmental conditions. A pot experiment was conducted in a greenhouse under simulated growth conditions with four soil moisture contents (80, 65, 50 and 35% relative saturation moisture content) and three temperature conditions (15, 20 and 25°C). Physiological (relative water content and root activity) and biochemical parameters (chlorophyll, peroxidase (POD), malondialdehyde (MDA), soluble protein, soluble sugar and free proline) were evaluated at the seedling stage. Results showed that with a decrease in soil water content, the POD activities, MDA content, soluble protein content, soluble sugar content and free proline content of plants under the 15°C and 20°C treatments initially decreased and then increased, whereas they increased with a decrease of soil water content at 25°C. The relative water contents of plants under the three temperature treatments decreased with a decreasing soil moisture content, but then increased temperature significantly reduced the relative water content of the seedlings under low soil water content. The chlorophyll contents of plants under the 25°C treatment decreased with a decrease of soil moisture content, but those of plants under the 15°C and 20°C treatments initially increased and then decreased. The root activities of plants under the 15°C and 20°C treatments increased with a decreasing soil moisture content; however, those of plants under the 25°C treatment initially increased and then decreased. Thus, results indicated that changes of temperature and soil moisture content had significant and complicated effects on the physiological-biochemical characteristics of F. sinensis; the conditions of 20°C and 65% RSMC had positive effects on F. sinensis seedling growth and the appropriate drought stress could promote the growth of seedling roots under the three different temperature conditions. In conclusion, F. sinensis seedlings could adapt to certain changes in the ecological environment by regulating their physiological and biochemical reactions.

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.

Root effects on soil water and hydraulic properties

Biologia ◽  
2007 ◽  
Vol 62 (5) ◽  
Author(s):  
Horst Gerke ◽  
Rolf Kuchenbuch
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
Root Effects

AbstractPlants can affect soil moisture and the soil hydraulic properties both directly by root water uptake and indirectly by modifying the soil structure. Furthermore, water in plant roots is mostly neglected when studying soil hydraulic properties. In this contribution, we analyze effects of the moisture content inside roots as compared to bulk soil moisture contents and speculate on implications of non-capillary-bound root water for determination of soil moisture and calibration of soil hydraulic properties.In a field crop of maize (Zea mays) of 75 cm row spacing, we sampled the total soil volumes of 0.7 m × 0.4 m and 0.3 m deep plots at the time of tasseling. For each of the 84 soil cubes of 10 cm edge length, root mass and length as well as moisture content and soil bulk density were determined. Roots were separated in 3 size classes for which a mean root porosity of 0.82 was obtained from the relation between root dry mass density and root bulk density using pycnometers. The spatially distributed fractions of root water contents were compared with those of the water in capillary pores of the soil matrix.Water inside roots was mostly below 2–5% of total soil water content; however, locally near the plant rows it was up to 20%. The results suggest that soil moisture in roots should be separately considered. Upon drying, the relation between the soil and root water may change towards water remaining in roots. Relations depend especially on soil water retention properties, growth stages, and root distributions. Gravimetric soil water content measurement could be misleading and TDR probes providing an integrated signal are difficult to interpret. Root effects should be more intensively studied for improved field soil water balance calculations.

Development of calibration algorithms for selected water content reflectometry probes for burned and non-burned organic soils of Alaska

2010 ◽  
Vol 19 (7) ◽  
pp. 961 ◽  
Author(s):  
Laura L. Bourgeau-Chavez ◽  
Gordon C. Garwood ◽  
Kevin Riordan ◽  
Benjamin W. Koziol ◽  
James Slawski
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Soil Profile ◽  
Soil Moisture Content ◽  
Mineral Soil ◽  
Organic Soil ◽  
Organic Content ◽  
Organic Soils ◽  
Probe Type

Water content reflectometry is a method used by many commercial manufacturers of affordable sensors to electronically estimate soil moisture content. Field‐deployable and handheld water content reflectometry probes were used in a variety of organic soil‐profile types in Alaska. These probes were calibrated using 65 organic soil samples harvested from these burned and unburned, primarily moss‐dominated sites in the boreal forest. Probe output was compared with gravimetrically measured volumetric moisture content, to produce calibration algorithms for surface‐down‐inserted handheld probes in specific soil‐profile types, as well as field‐deployable horizontally inserted probes in specific organic soil horizons. General organic algorithms for each probe type were also developed. Calibrations are statistically compared to determine their suitability. The resulting calibrations showed good agreement with in situ validation and varied from the default mineral‐soil‐based calibrations by 20% or more. These results are of particular interest to researchers measuring soil moisture content with water content reflectometry probes in soils with high organic content.

scholarly journals Geostatistical analysis for soil moisture content under the no tillage cropping system

2006 ◽  
Vol 63 (4) ◽  
pp. 341-350 ◽  
Author(s):  
Célia Regina Grego ◽  
Sidney Rosa Vieira ◽  
Aline Maria Antonio ◽  
Simone Cristina Della Rosa
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Spatial Variability ◽  
Water Content ◽  
Spatial Dependence ◽  
Soil Moisture Content ◽  
No Tillage ◽  
Moisture Contents ◽  
Classical Statistics ◽  
Evaluation Point

Experiments in agriculture usually consider the topsoil properties to be uniform in space and, for this reason, often make inadequate use of the results. The objective of this study was to assess the variability for soil moisture content using geostatistical techniques. The experiment was carried out on a Rhodic Ferralsol (typic Haplorthox) in Campinas, SP, Brazil, in an area of 3.42 ha cultivated under the no tillage system, and the sampling was made in a grid of 102 points spaced 10 m x 20 m. Access tubes were inserted down to one meter at each evaluation point in order to measure soil moisture contents (cm³ cm-3) at depths of 30, 60 and 90 cm with a neutron moisture gauge. Samplings were made between the months of August and September of 2003 and in January 2004. The soil moisture content for each sampling date was analyzed using classical statistics in order to appropriately describe the central tendency and dispersion on the data and then using geostatistics to describe the spatial variability. The comparison between the spatial variability for different samplings was made examining scaled semivariograms. Water content was mapped using interpolated values with punctual kriging. The semivariograms showed that, at the 60 cm depth, soil water content had moderate spatial dependence with ranges between 90 and 110 m. However, no spatial dependence was found for 30 and 90 cm depths in 2003. Sampling density was insufficient for an adequate characterization of the spatial variability of soil moisture contents at the 30 and 90 cm depths.

scholarly journals EFFECTS OF HYDROPHILIC POLYMERS AND ORGANIC AMENDMENTS ON ESTABLISHMENT OF KENTUCKY BLUEGRASS.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 588a-588
Author(s):  
A. James Downer ◽  
Ben Faber ◽  
Richard White
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Soil Moisture Content ◽  
Organic Amendments ◽  
Kentucky Bluegrass ◽  
Soil Bulk Density ◽  
Time Domain Reflectometry ◽  
Peat Moss ◽  
Turf Quality

Three polymers (a polyacrylamide, polyacrylate and a propenoate-propenamide copolymer) and three organic amendments (peat moss, wood shavings, and composted yardwaste) were incorporated at five rates in a sandy soil to 15cm depth. Soil moisture content was determined by time domain reflectometry and gravimetrically. Only the highest polymer rates (2928kg/ha [60#/1000sq.ft.]) produced significant increases in soil moisture content and reductions of soil bulk density. Peat moss and yardwaste increased soil water content while shavings decreased water content. Turf quality scores were not affected by polymers but were initially reduced by yardwaste and shavings.

scholarly journals PENGARUH CEKAMAN KURANG AIR TERHADAP BEBERAPA KARAKTER FISIOLOGIS TANAMAN NILAM (Pogostemon cablin Benth)

2020 ◽  
Vol 19 (3) ◽  
pp. 108
Author(s):  
SETIAWAN SETIAWAN ◽  
TOHARI TOHARI ◽  
DJA’FAR SHIDDIEQ
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Water Deficit ◽  
Relative Water Content ◽  
Soil Moisture Content ◽  
Block Design ◽  
Leaf Water ◽  
Pogostemon Cablin ◽  
Relative Water

<p>ABSTRAK<br />Nilam (Pogostemon cablin Benth) merupakan salah satu tanaman<br />penghasil minyak atsiri yang dikenal dengan minyak nilam (patchouli oil).<br />Salah satu kendala dalam pengembangan tanaman nilam adalah peka<br />terhadap kekurangan air. Perubahan iklim cenderung menyebabkan lebih<br />sering terjadi kekeringan di sejumlah wilayah termasuk Indonesia sehingga<br />dalam pengembangan tanaman nilam diperlukan varietas toleran terhadap<br />cekaman kurang air. Terdapat tiga varietas unggul nilam (Tapaktuan,<br />Sidikalang, dan Lhokseumawe) dengan produksi minyak (290-375 kg/ha)<br />dengan kadar patchouli alkohol 32–33%. Penelitian bertujuan untuk<br />mengevaluasi respon fisiologis 4 varietas/aksesi tanaman nilam terhadap<br />cekaman kurang air. Penelitian dilaksanakan di rumah kaca di Bogor pada<br />tahun 2012. Penelitian menggunakan RAK faktorial dengan tiga ulangan.<br />Faktor  pertama  4  varietas/aksesi  nilam  (V)  yaitu  Sidikalang,<br />Lhokseumawe, Tapaktuan, dan Bio-4. Faktor kedua empat interval<br />penyiraman (W) yaitu 1, 3, 6, dan 9 hari sekali. Evaluasi pengaruh<br />cekaman kurang air dilakukan terhadap beberapa karakter fisiologi<br />tanaman nilam. Pengamatan dilakukan antara lain terhadap peubah kadar<br />lengas tanah, konduktivitas stomata (Gs), laju transpirasi (Tr), kandungan<br />air nisbi (KAN), potensial air daun (PAD) dan kandungan prolin daun.<br />Hasil penelitian menunjukkan bahwa terjadi penurunan kadar lengas tanah,<br />konduktivitas stomata, laju transpirasi, dan KAN pada semua varietas,<br />sedangkan PAD dan kadar prolin meningkat seiring dengan semakin<br />lamanya interval penyiraman. Kadar prolin tertinggi pada interval 9 hari<br />sekali pada varietas Sidikalang. Tidak terdapat perbedaan respon<br />varietas/aksesi nilam yang diuji.<br />Kata kunci: Pogostemon cablin Benth, cekaman kurang air, karakter<br />fisiologis.</p><p>ABSTRACT<br />Patchouli (Pogostemon cablin Benth) is one of plant that produces<br />patchouli oil call patchouli oil. However, patchouli is susceptible to<br />drought. The effect of global warming which changes rainfall pattern<br />caused droughts in several regions including Indonesia. Therefore, it is<br />important to find patchouli variety which is relatively tolerant to drought.<br />Tapaktuan, Sidikalang, dan Lhokseumawe are three varieties of patchouli<br />which produce high essential oil (290-375 kg/ha) with high patchouli<br />alcohol content (32–33%). The objective of this research was to evaluate<br />the physiological responses of four varieties/clone of patchouli to drought.<br />The experiment was conducted at greenhouse at Cimanggu, Bogor from<br />February to July 2012. The research was designed in randomized factorial<br />block design (RBD) with three replications. The first factor was four<br />varieties/clone of patchouli (V) Sidikalang, Lhokseumawe, Tapaktuan, and<br />Bio-4. The second factor was four watering intervals (W) every 1, 3, 6<br />and 9 days of watering. Parameters evaluated were physiological<br />characteristics, soil moisture content, stomatal conductance, transpiration<br />rate (Tr), leaf water potential, relative water content, and proline content of<br />leaf. The results showed that soil moisture content, stomatal conductivity,<br />transpiration rate and relative water content decreased, while leaf water<br />potential and proline levels increased along with the increase of watering<br />intervals. The highest proline level was at interval of nine days watering<br />treatment on Sidikalang varieties. However, all varieties/clone have not<br />different responses to water deficit.<br />Key words: Pogostemon  cablin  Benth,water  deficit,  physiological<br />characteristics</p>

scholarly journals Physiological responses to drought of Cnidoscolus quercifolius Pohl in semi-arid conditions

2019 ◽  
Vol 6 (1) ◽  
pp. 493 ◽  
Author(s):  
Fabio Rodrigues Ramos ◽  
Antonio Lucineudo Oliveira Freire
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Moisture Content ◽  
Water Content ◽  
Water Use ◽  
Transpiration Rate ◽  
Relative Water Content ◽  
Soil Moisture Content ◽  
Relative Water ◽  
Use Efficiency

This study aimed to evaluate the physiological behavior of faveleira (Cnidoscolus quercifolius Pohl) plants grown in the field, in Caatinga, during wet and dry seasons. Adult plants were selected for evaluation in March and April (wet season) and May and June (dry season), during 2016. We evaluated the soil water content, water potential (Ψw), osmotic potential (Ψπ), relative water content (RWC), stomatal conductance (gs), transpiration rate (E), photosynthetic rate (A), intercellular CO2 concentration (Ci), instantaneous water use efficiency (A/E) and carboxylation efficiency (A/Ci). The reduction in water availability in the soil promoted a marked decrease in soil water potential, which was more affected than the relative water content. The opening of the stomata was affected by the decrease in soil moisture content, reducing the stomatal conductance, transpiration rate, photosynthesis rate, instantaneous water use efficiency and carboxylation efficiency. The photosynthesis was more affected than transpiration by the reduction in soil moisture content.

scholarly journals Effects of the Soil Moisture Content on the Superoxide Anion and Proline Contents in Soybean Leaves

2021 ◽  
Author(s):  
Zihao Wu ◽  
Xiyue Wang ◽  
Xin Wang ◽  
Chao Yan ◽  
Chunmei Ma ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Superoxide Anion ◽  
Soil Moisture Content ◽  
Volumetric Water Content ◽  
Drought Tolerant ◽  
Soybean Plants ◽  
Feed Protein ◽  
Soybean Leaves

Background: As an important source of feed protein, soybean is involved in the processing industry, food industry and other fields. Therefore, in recent years, the demand for soybean has increased and soybean planting areas have also increased. However, frequent droughts have a serious impact on soybean yield. Methods: During the flowering period, the soybean plants were subjected to drought treatments of different degrees (0-7 days without water). The superoxide anion and proline contents in the leaves were determined. Then, fitting curves were drawn between the soil moisture content and the superoxide anion and proline contents. Result: The effects of different soil moisture contents on the superoxide anion and proline contents in soybean leaves and the correlation between these contents were analyzed. According to the fitting curves, with a decrease in the volumetric water content of soil, the superoxide anion and proline contents in soybean leaves increased. The superoxide anion contents in drought-tolerant cultivars were significantly lower than those in drought-sensitive cultivars and the proline contents were significantly higher in drought-tolerant cultivars than those in drought-sensitive cultivars. The superoxide anion content in soybean leaves was positively correlated with the proline content in the soil volumetric water content range of 31.5% to 14.5%.

scholarly journals Effects of Water Immersion and Soil Moisture Content on Larval and Pupal Survival of Bactrocera minax (Diptera: Tephritidae)

Insects ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 138 ◽  
Author(s):  
Zaiyuan Li ◽  
Consolatha Chambi ◽  
Tianhua Du ◽  
Cong Huang ◽  
Fulian Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Soil Moisture Content ◽  
Southern China ◽  
Water Immersion ◽  
High Water ◽  
High Rate ◽  
High Water Content ◽  
Respiration Rates

Bactrocera minax, one of the most devastating citrus pests in Asia, has two developmental stages (mature larva and pupa) that complete their life cycle in the soil. Currently, southern China has a climate with abundant autumn rains, and soil moisture can be a major factor affecting the survival of larvae and pupae of B. minax. In the present study, we evaluated the effects of water immersion and high soil moisture content on the development of mature larvae and pupae of B. minax. When immersed in water for 1 d, 100% of mature larvae of B. minax were knocked out. When larvae were immersed for less than 6 d, however, more than 92% of knocked-out larvae recovered within 24 h. The days of water immersion with 50% and 90% recovery ratios (indicated as RD50 and RD90) were 10.3 d and 6.4 d, respectively. When larvae were immersed less than 6 d, the mortality ratios of larvae were not significantly different from those that were not immersed at all. The days of immersion causing 50% and 90% mortality of larvae (MD50 and MD90, respectively) were 7.6 d and 11.1 d, respectively. The pupation ratios of larvae were also observed to be not significantly different compared to non-immersion, and the days of immersion causing 50% and 90% pupation (PD50 and PD90, respectively) were 6.6 d and 0.8 d, respectively. Larval respiration rates were reduced after water immersion as a strategy for larval survival. High water content was not detrimental to pupae of B. minax. Adult emergence did not significantly decrease in soil with high water content, even though pupae were under those conditions for 161–175 d. The respiration rates of pupae were lower in soil with different moisture levels and were not significantly different, which ensured the survival of pupae in high water content. Reduced respiration rate is a strategy for survival of larvae and pupae, and remarkable tolerance to high moisture conditions could explain the high rate of spread and geographical distribution of B. minax. The results of this study provide a reference for the occurrence and control of B. minax.

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