Different Levels Of Soil Moisture Research Articles

Gas exchange and fluorescence in ‘sutil’ lime (Citrus aurantifolia Swingle) under different soil moisture levels

The Portoviejo valley in the Manabi province, Ecuador, is an important ‘Sutil’ lime (Citrus aurantifolia Swingle) producer, but since the water resources in the region are of vital importance, a good management of the irrigation is needed. The objective of this research was to know the physiological response of the plant expressed in terms of gas exchange and fluorescence, under different levels of irrigation. The study zone is located at Maconta site, 40 masl, in an orchard with 15 year old plants grafted on rootstock ‘Cleopatra’, planted at 6 x 6 m. The following irrigation treatments were tested, according to the atmospheric demand: 0.3ET0, 0.5ET0, 0.7ET0, 0.9ET0, and a control (farmer's irrigation). A randomized complete block design with five treatments and six replications was established. Significant differences (P≤0,05) were found among treatments measured in the dry season, where the photosynthesis rate (A) was higher in the control treatment, decreasing in those treatments with water restrictions (0,3ET0) or excess (0,9ET0) in the soil. Similar behavior was observed in stomatal conductance (gs) and transpiration (T); the increase or decrease of A, would be associated with T and gs. The water use efficiency (WUE) was higher in the treatment of 0,5ET0 than in the rest of treatments, suggesting that the increase in this variable would be due to a good equilibrium of the Ci/Ca, ratio, avoiding water loss and still maintaining active physiological processes. Low values of the Fv/Fm ratio existed in conditions of excess moisture. The performance of gs in both periods leads to deduce the rapid adaptation of the crop to different levels of soil moisture.

Synergism Between Water Management and Phosphorus Supply Enhances the Nodulation and Root Growth and Development of Chinese Milk Vetch (Astragalus sinicus L.).

The response of root development and nodule formation of the manure crop Chinese milk vetch to different levels of soil moisture and phosphorous (P) fertilizer remains unclear. In this study, a pot experiment was performed to trace the root growth and nodule formation of Chinese milk vetch at the seedling, branching and full-flowering stages, under various soil moisture gradients [25% (W1), 50% (W2), 75% (W3), and 100% (W4) of the maximum field water-holding capacity] and P levels [0 (P0), 30 (P1), 60 (P2), and 90 (P3) kg hm–2]. The root/shoot ratio, root vitality, number of nodules, nodule weight, and nitrogenase activity were affected remarkably by soil moisture or the level of added P across the whole stage. Differences were found in the interaction effect between soil moisture and added P on the characteristic indices of the root and nodule at the different growth stages. There were obvious differences in root activity and nitrogenase activity at seedling stage, but no evident differences were found in other indices. Certain differences were also found in the indicators mentioned above at the branching stage. W1P0 and W2P0 showed the highest root/shoot ratio, W2P2 and W3P2 resulted in the highest root activity; W3P3 and W3P2 had the highest number and weight of nodules; and W3P2, W2P2, and W3P1 had higher nitrogenase activity than the other treatments at the full-flowering stage. The application of P at 60 kg hm–2 and the relative soil moisture of 75% was the best P-water combination suitable for the root development, nodule formation, and nitrogen fixation of Chinese milk vetch. This study will provide a theoretical basis for the production of this plant by managing the synergistic interaction between P fertilizer and soil moisture.

Biodegradation of a Nanocellulose Superabsorbent and Its Effect on the Growth of Spinach (Spinacea oleracea)

In this study, spinach (Spinacea oleracea) plants were grown in two soils, a clay loam (CL) and a sandy (SD) soil, amended with two types of superabsorbent polymers (SAPs), nanocellulose and commercial, at different levels of soil moisture: 70, 40, and 20%. The effect of the superabsorbent on the soil properties, water management, and plant biomass was measured and compared to that in soils treated with a commercial anionic polyacrylamide-based SAP. Plant biomass is the highest in SD soil amended with a commercial superabsorbent. However, it decreases in the CL soil when a superabsorbent is applied, independent of the SAP type. This effect is magnified when a nanocellulose SAP is used; this is likely attributed to waterlogging stress and the fast biodegradation of this superabsorbent, where approximately 50% of the initial mass remains after 5 days of exposure. The use of a nanocellulose SAP as a water retention agent offers the potential for a much-needed sustainable solution for global agriculture. Future studies are needed to modify the structure of the nanocellulose SAP to inhibit its biodegradation and increase its benefits for agricultural use.

Effect of Different Levels of Soil Moisture and Trichoderma Viride in Controlling Black Scurf of Potato

Effect of Different Levels of Soil Moisture and Trichoderma Viride in Controlling Black Scurf of Potato

ПРОГНОЗИРОВАНИЕ КОНТУРОВ КАПЕЛЬНОГО УВЛАЖНЕНИЯ ЧЕРНОЗЕМОВ СТЕПНОГО ТИПА ПОЧВООБРАЗОВАНИЯ

Purpose: development and testing of a method for determining the size and moisture characteristics of moisture contours formed in the southern chernozems of the steppe type of soil formation during drip irrigation. Materials and methods. Experimental studies were carried out on light, medium and heavy loamy medium thick ordinary and southern chernozems. The vertical sections of humidification zones with a system of in-contour moisture isopleths were considered. As indicators determining the contour parameters, the following are considered: the content of physical clay in the moistened soil layer, the soil density and its lowest moisture capacity. Results. In the process of studying the experimental vertical sections of soil drip moistening zones, dependences characterizing the existing functional relationships between the contour geometric parameters and the characteristics of soil, phytosoil and technological conditions of their formation were determined. On the basis of the obtained experimental dependences, a method for calculating the contours linear dimensions and graphically constructing their outlines has been developed. The proposed method for contour predicting was tested on actual data on their sizes and moisture distribution in the inner-contour space, obtained by other researchers experimentally. Comparison of the experimental and predicted contours of drip moistening testifies to their qualitative similarity both in terms of the external outline and in terms of the location of isopleths with different levels of soil moisture inside the wetted zone. The calculated value of the irrigation rate differs from the actual one by 2.2 %. Conclusions. The proposed method for predicting the sizes of moisture contours and intra-contour isopleths, formed in chernozems of the steppe type of soil formation, was developed to the level of calculations using the author's computer program. An example of approbation of the proposed method indicates its acceptability for use in the crops drip irrigation design and operational practice.

Earthworm Burrowing Activity and Its Effects on Soil Hydraulic Properties under Different Soil Moisture Conditions from the Loess Plateau, China

Earthworm activity has become more important in the Loess Plateau, where hydrological processes are crucial for ecosystem sustainability. In this study, we conducted a laboratory microcosm experiment to determine the various burrowing activities of Eisenia fetida and their impact on the soil hydraulic properties in response to different levels of soil moisture (50%, 70%, 90% of field capacity) in two common soil types (loessial and Lou soil) obtained from the Loess Plateau. Burrowing activity of E. fetida increased with higher soil moisture and was greater in loessial than in Lou soil. Most burrowing activities occurred within the top 5 cm and decreased with increasing soil depth. Macropores and burrow branching, which are highly related to the earthworm burrowing, were more prevalent in wetter soil. Earthworms significantly altered the formation of large soil aggregates (AGL, diameter >2 mm) under different soil moistures and depths. Distinct earthworm burrowing activities, controlled by soil moisture, altered soil hydraulic properties. However, soil saturated hydraulic conductivity (Ks) showed little differences between different treatments due to the horizontal and high–branched burrows of E. fetida, although higher burrowing activities were found in wetter soil. Soil field capacity was highest in drier soil due to the less macropores and burrowing activities.

Prolonged drought stress induced changes in yield and physiological processes of Trifolium repens and Festulolium braunii

Water deficit is one of the main environmental factors, and the recognition of plant response to drought stress seems to be crucial for the yield improvement of the important crops. The aim of the study was to investigate the effect of prolonged drought stress on dry matter yield, gas exchange parameters, and relative chlorophyll content in the leaves of Festulolium braunii and Trifolium repens grown in pure stands and in mixture. In the pot experiment, different levels of soil moisture (well-watered conditions and drought stress) and of cultivation method (pure stand and mixture) have been applied. The study has shown that all measured parameters were affected by drought stress. Dry mass yield, net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance were significantly lower under drought stress than under well-watered conditions in all treatment types. T. repens showed the strongest response to stress, whereas F. braunii the weakest when both those species were grown in the pure stand. Under drought conditions, the yield of the mixture was similar to that of F. braunii cultivated in the pure stand, and significantly higher than that of T. repens cultivated in the pure stand. It was also found that under the stress, PN and E of both species in the the mixture was higher than in the pure stand. The highest water use efficiency was observed in F. braunii grown in the mixture. Our research shows, that in regions with limited rainfall, T. repens is more useful for growing in a mixture with F. braunii, than in the pure stand.

Poblaciones de Pinus radiata D. Don difieren en la tolerancia a bajas temperaturas y en la tasa de crecimiento

Introduction: In Pinus radiata D. Don, one of the most widely planted pines globally, frost damages plantations at the seedling stage. Objective: To determine differences in growth and tolerance to low temperatures of native populations (Guadalupe and Cedros islands) of P. radiata in greenhouse and outdoors conditions, under different levels of soil moisture. Materials and methods: Low-temperature tolerance was determined through the damage index (DI) in freezing tests at -12 °C during 4 h. In each environment (greenhouse and outdoors) two soil moisture treatments were defined (irrigation and drought). The DI was evaluated with the method of electrical conductivity in primary needles during winter and spring. The absolute growth rate (AGR) of the terminal shoot was obtained by measuring the total height of the seedlings. Results and discussion: Average DI of 50 and 64 % were obtained in winter and spring, respectively. In greenhouse, DI was different (P ≤ 0.05) between populations, being higher in Guadalupe (>59 %) than in Cedros ( Conclusion: The population of Guadalupe is more sensitive to low temperatures with greater variation in DI, due to its growth dynamics. Differences between populations are useful in the genetic improvement of the species.

Phenotypic plasticity in diaspore production of a amphi-basicarpic cold desert annual that produces polymorphic diaspores

Phenotypic plasticity has been studied in diaspore-dimorphic species, but no such study has been done on a diaspore-polymorphic species. Our aim was to determine the effects of abiotic and biotic factors on phenotypic plasticity of the diaspore-polymorphic cold desert annual Ceratocarpus arenarius. Plants produced from dispersal units near the soil surface (a, basicarps) and at the middle (c) and upper (f) parts of the plant canopy were subjected to different levels of soil moisture, nutrient supply and intramorph and intermorph densities. Different levels of these biotic and abiotic factors resulted in significant variation in total plant mass, diaspore mass, mass allocation to stem and reproductive organs and total number and proportion of morphs a, c and f on an individual. The effect of stress on number and mass of a dispersal unit morph varied by treatment, with dispersal unit f having the highest CV and dispersal unit a the lowest. The success of this diaspore polymorphic species in its rainfall-unpredictable environment likely is enhanced by plasticity in production of the different types of diaspores.

Effect of tillage practices at different levels of soil moisture on some soil properties and maize productivity

A field experiment was carried out during the early summer seasons of 2018, at Agricultural Research Centre (ARC) Giza, Egypt. This study aims to examine the effect of three tillage treatments under three different moisture contents on some soil properties and on maize crop production. The experiments included three moisture contents of (MC1, 27.2 %), (MC2, 15.4 %) and (MC3, 7.2 %); as well as three tillage treatments, no-tillage control (NT), minimum tillage (MT) and conventional tillage (CT). The experimental was laid out in split-split plot design with four replications. The results showed that, there was significant effect of tillage at different moisture levels on soil physical and chemical properties. It was also indicated that the effect of tillage practices was significantly on soil bulk density, total porosity, hydraulic conductivity and moisture constants, where the conventional tillage at soil moisture level 15.4% (MC2) helped in improving soil bulk density, hydraulic conductivity and total porosity. Soil organic C, cations exchange capacity CEC, available N, P and K were improved in the soil surface layer of NT and decreased with depth. Clod mean weight diameter of soil was improved with 15.4-% of soil moisture content regardless of tillage depth and enhanced root proliferation by increasing density roots compared with minimum and no tillage in maize plant. The grain yields of maize were improving more under conventional tillage at moisture content 15.4% compared with other treatments. It was found that plant height and roots value increased by using conventional tillage compared with other tillage treatments.

Effects of different levels of soil moisture and indigenous organic amendments on the yield of boro rice grown under field condition

A field study was conducted to determine the potentials of moist (70% soil moisture) and saturated (> 100% soil moisture) soil conditions and organic amendments of rice straw compost (RSC), mustard meal (MM) and trichocompost (TC) on the selected rice varieties of BR 3, local BRRI dhan 29 and BRRI dhan 74 in relation to the growth and yield attributes of rice varieties. The rates of amendments were 0, 4, 8 t/ha for RSC; 0, 3, 6 t/ha for MM and 0, 2.5, 5 t/ha for TC. The maximum grain yield of 8.71 t/ha was attained from the RSC4ML100 and 8.58 t/ha from RSC4ML70 treatments. The moist condition of soil had almost similar effects on the number of productive tillers, grain yield, number of filled and fissured grains, 1000-grain weight and harvest index as compared to saturated condition along with the doses of RSC, MM and TC. The RSC (4 t/ha) was the superior treatment with respect to the growth and yield components of rice followed by the treatments of TC (2.5 t/ha) and MM (3 t/ha), irrespective of rice varieties and moisture levels.
 Dhaka Univ. J. Biol. Sci. 29(1): 87-96, 2020 (January)

Зависимость дыхания стволов дуба разных классов роста от условий окружающей среды

Зависимость дыхания стволов дуба разных классов роста от условий окружающей среды

A Low-cost Soil Moisture Monitoring Method by Using Walabot and Machine Learning Algorithms

Soil moisture plays an important role in agricultural processes, which has a significant effect on crop evapotranspiration, the exchange of water, and energy fluxes. Recently, soil moisture can be measured by remote sensing or proximate sensing techniques, such as thermal, optical, and microwave measurements. However, there are limitations to the applications of these methods, such as low spatial resolution, limited surface penetration, and vegetation. In this study, it proposed a new low-cost soil moisture monitoring method by using a Walabot sensor and machine learning algorithms. Walabot is a pocket-sized device cutting-edge technology for Radio Frequency tridimensional sensing. Unlike the remote sensing tools such as unmanned aerial vehicles (UAVs) limited by cloud cover or payload capability, the Walabot can be used flexibly in the field and provide data information more promptly and accurately than UAVs or satellite. By putting different moisture levels of soil on the Walabot, the Walabot can collect radio frequency reflectance data from different levels of soil moisture. Then, machine learning algorithms, such as principal component analysis (PCA), linear discriminant analysis (LDA), have been applied for data processing. Results showed that Walabot has a state-of-art performance in estimating soil moisture.

How different soil moisture levels affect the microbial activity

ABSTRACT: The lowland soils are characterized by high susceptibility to water saturation. This anaerobic condition is usually reported in paddy fields and alters the decomposition process of soil organic compounds. The aim of this study was to evaluate the soil microbial and enzymatic activity of a lowland soil at different soil moisture contents. A poorly drained Albaqualf cultivated with irrigated rice was used to evaluate microbial and enzymatic activity in treatments with different levels of soil moisture, being: i) 60% of field capacity (FC) (60%FC); ii) 100% of FC (100%FC); iii) flooded soil with a 2 cm water layer above soil surface, and iv) soil kept at 60%FC with late flood after 29 days the incubation. The greater soil microbial activity was observed in the 100%FC treatment, being 41% greater than 60%FC treatment and only 2% higher than flooded treatment. The enzymatic activity data by fluorescein diacetate (FDA) hydrolysis corroborated the higher CO2 release in treatments with higher soil moisture content. Differently from the results reported, the main methodologies to evaluate microbial activity still recommend maintenance of the soil with a moisture content close to 60% of the FC. However, in lowland soil with history of frequent paddy fields, the maintenance of moisture close to 60% of the FC can limit the microbial activity. The soil respiration technique can be used to evaluate the microbial activity in flooded soil conditions. However, further studies should be conducted to understand the effect of the cultivation history on the microbial community of these environments.

THE METHOD OF STUDYING WATER CONSUMPTION OF CROPS IN FIELD VEGETATION EXPERIMENTS

Facing the global climate change, the study of the water consumption of new varieties and hybrids of crops becomes an urgent problem because of the need for economical use of available water resources in the production process and adaptation of agro-technologies to climate change. The purpose of the research is to study the patterns of water consumption of new varieties of crops on the basis of instrumental daily measurement of the dynamics of components of the total water consumption of crops – evaporation and transpiration under different systems of their fertilizers and different levels of soil moisture. The developed method of instrumental measurement of the components of total water consumption is based on the use of ceramic membranes to automatically maintain different levels of soil moisture in the field vegetation experience under the influence of natural climatic factors. A two-factor vegetation experiment allows a comparative analysis of the structure of water consumption of crops at different levels of soil moisture and different fertilizer systems. The constructive decisions and history of creation and formation of field vegetation experiments with controlled level of soil moisture supply, their advantages and disadvantages are presented. Since 2017, the field of vegetation field experiments has functioned on a permanent basis in the village of Gora, Boryspil district, Kiev region. The advantage of these experiments is the high reliability of the obtained patterns, which provides a sufficient number of replicates in each variant; instrumental measurement of constituents of water consumption – evaporation from soil, total water consumption and, by difference, transpiration of plants that can be monitored on a daily basis, and even on an hourly basis; the dual action of the moisture supply device allows both to supply water to the soil and to divert excess water after precipitation to the storage tanks, which prevents anaerobiosis in the soil. According to the results of the conducted experiments, regularities of fundamental character were established: the ratio of evaporation and transpiration during the period of vegetation of crops was quantified; the influence of different fertilizer systems on the components of total water consumption of crops has been reliably established, in particular the influence of microbiological preparations and the participation of soil biota in the water consumption have been proved; factor analysis proved the equivalence of moisture supply factors (38 %) and fertilizer (36 %) on buckwheat grain productivity; under conditions of guaranteed moisture supply, soil biota improves soil fertility parameters. Conclusions. The fundamental result of vegetation experiments is the reliable establishment of the influence of different fertilizer systems on the components of water consumption of crops and in particular microbiological preparations, the participation of soil biota in soil moisture consumption, as well as its positive effect on the growth of the parameters of soil fertility substance, most likely due to the development of micro- and mesobiota (algae, moss, etc.) under conditions of guaranteed soil moisture. The method of conducting field vegetation experiments with regulation of soil moisture level developed at the Institute of Water Problems and Land Reclamation is indispensable for instrumental study of the patterns of evaporation and transpiration during the growing season of agricultural crops, which are further used in the scenario modeling of agrotechnological technologies. also rainfed agriculture for long-term forecasts of security and the growing season, which is aimed at the economical use of moisture in the production process.The possibility of a direct comparative assessment of water consumption of different new varieties and hybrids of crops at different levels of soil moisture in the field vegetation experiment remains unrealized.Field vegetation experiment has a high demonstration and educational potential for teaching undergraduate and graduate students.

Northward migration of trembling aspen will increase growth but reduce resistance to drought-induced xylem cavitation

Tree migration to higher latitudes may occur in response to future changes in climate, exposing the trees to higher concentrations of carbon dioxide ([CO2]), new photoperiods, different levels of soil moisture, and other new conditions. These new conditions can influence the physiology, survival, and growth of trees. This study examined the interactive effects of [CO2], photoperiod, and soil moisture on the morphology and resistance to xylem cavitation in trembling aspen (Populus tremuloides Michx.). One-year-old seedlings, in greenhouses, were exposed to two [CO2] (ambient [CO2] 400 μmol·mol−1 or an elevated [CO2] 1000 μmol·mol−1), four photoperiod regimes corresponding to latitudes 48°N (seed origin), 52°N, 55°N, and 58°N, and two levels of soil moisture (60%–75% and 13%–20% of field capacity) for one growing season. Seedling growth, leaf size, specific leaf area, biomass allocation, and xylem resistance to cavitation (water potentials for 20%, 50%, and 80% loss of hydraulic conductivity) were assessed. The seedlings under the longest photoperiod regime (58°N latitude) had greatest height and biomass but smallest specific leaf area. Under the elevated [CO2], however, the longest photoperiod regime significantly reduced xylem resistance to drought-induced cavitation compared with the photoperiod corresponding to 48°N. These results suggest that when migrating to higher latitudes, trembling aspen may grow faster but could become less resistant to drought and more prone to hydraulic failure during a drought spell.

Genetic Diversity in Annual Xerohalophytes of the Family Chenopodiaceae along Soil Moisture and Salinity Gradients

Genetic polymorphism has been studied in populations of two annual xerohalophyte species of the family Chenopodiaceae, Atriplex tatarica and Sedobassia sedoides, growing on soils with different levels of soil moisture and sodium and potassium ion contents. A tendency toward decrease in the percentage of polymorphic loci in A. tatarica at higher soil salinity and increase in the observed heterozygosity of S. sedoides populations at higher levels of soil potassium has been revealed, with parameters of genetic variation in either species showing no dependence on soil moisture. Soil potassium deficiency is a stress factor for S. sedoides at both physiological and population-genetic levels. Mechanisms controlling sodium absorption and maintaining ion homeostasis and also a high level of homozygosity in S. sedoides indicate the improvement of stress tolerance in this annual species.

Research Article Expression of transcription factors involved with dehydration in contrasting rice genotypes submitted to different levels of soil moisture

Research Article Expression of transcription factors involved with dehydration in contrasting rice genotypes submitted to different levels of soil moisture

Anatomical adaptations to different soil moisture contents in palisade grass and smooth pigweed

ABSTRACT Weed adaptations to different environments contribute to their success in establishing in different agroecosystems. A greenhouse and laboratory study was carried out to evaluate the effects of different levels of soil moisture on the anatomical characteristics of two weed species. The treatments were arranged in a 2 x 5 factorial design, with the first factor representing the weed species (Amaranthus hybridus and Brachiaria brizantha) and the second factor being the soil moisture levels in which they were grown (100%, 80%, 74%, 67%, and 60% of field capacity). At 55 days after weed emergence, the material for anatomical evaluations was collected. The water stress affected the two weed species differently, causing changes both in the thickness of the tissues evaluated and in their proportions. These changes seem to be related to how each species tolerates water stress. A. hybridus showed thickening of all leaf tissue and change in the proportion of these tissues, whereas B. brizantha showed a decrease in thickness of the leaf tissue and an increase in the proportion of adaxial epidermal and parenchymal tissues.

Seed priming improves seedling emergence and reduces oxidative stress in Nigella sativa under soil moisture stress

ABSTRACTNigella sativa seeds have multiple industrial and pharmaceutical uses for the diseases treatment such as bronchitis, rheumatism, high blood pressure, cough, eczema, inflammation, and influenza. Although semi-arid areas are suitable for production of annual medicinal plants because they receive favorable amounts of solar radiations, the establishment of these plants' seedling requires frequent irrigations because their seeds are small and the climate is hot at the time of planting. When the irrigation sources are limited, poor establishment and inadequate production will result. Therefore, in order to improve nitrogen (N) in N. sativa seedling establishment, different effects of seed priming treatments were evaluated under drought stress. Different levels of soil moisture (irrigation after 11, 22, 33, and 44 mm of evaporation as no water stress, mild water stress, moderate water stress, and severe water stress, respectively) and seed priming treatments [no priming, potassium nitrate (KNO3), zinc sulfate (ZnSO4), polyethylene glycol 6000, and gibberellic acid (GA)] were evaluated as the main plot and subplot factors, respectively. The results showed that under mild water stress condition, seed priming significantly increased proline content and the highest percentage of emergence was obtained with ZnSO4. Furthermore, the highest amount of soluble protein was observed in the KNO3 treatment and the catalase enzyme content increased in all priming treatments, except polyethylene glycol treatment. Under moderate water stress condition, the KNO3 treatment raised the rate and percentage of emergence and the seedling length. However, under severe water stress condition, the highest percentage of emergence was achieved by GA and ZnSO4 treatments. Moreover, hydropriming and GA produced the highest proline content and seedling dry weight. Under moderate and severe water stress conditions, the hydropriming and ZnSO4 treatments showed a significant increase in catalase activity. It can be concluded that priming of N. sativa seeds with ZnSO4 and GA can alleviate drought stress in the early stages of seedling growth by increasing the antioxidants in the seedlings. Farmers in semi-arid regions can prime N. sativa seeds with these compounds before planting to increase production of this valuable medicinal plant and reduce water consumption.