Content In Soil Profile Research Articles

Capillary rise quantification improves irrigation performance in pear orchards

The shallow water table in Río Negro and Neuquén valley causes a capillary rise (CR) that modifies the water content in soil profile. Therefore, irrigation performance is expected to be affected by the capillary water input into the root zone. The aim of this study was to evaluate the effect of CR on surface irrigation performance during 2020-2021 growing season in a pear orchard. In a Bartlett pear orchard planted in 2003, three irrigation moments were evaluated, and irrigation sheets were calculated to obtain efficiency. Water table level (WTL) was measured monthly in an open aquifer piezometer. CR was calculated with the software UPFLOW. Soil water content was measured with a Frequency Domain Reflectometry (FDR) sensor at: 0.20 m, 0.40 m, and 0.60 m. Water use efficiency (WUE) and water productivity were calculated using pear crop yield and the irrigation sheets applied and the crop water demand, respectively. WTL was shallower in spring than in the rest of the season. The mean depth fluctuated between 0.70-1.20 m during spring, affecting irrigation performance. Data of FDR deepest sensor showed an increase of soil moisture due to CR. Capillary contribution negatively affects irrigation efficiency if it is not included in the water balance. Irrigation schedules can be re-arranged considering soil moisture and CR. In this way, the necessary water sheets could be applied in each crop development stage adjusted to water demand. Improving irrigation performance and WUE enables a sustainable water management strategy in pear production.

The performance of dry spell-based index to predict agricultural drought

This study was intended to analyze dry spell-based drought index (SDI) performance in predicting agricultural drought. Agricultural drought was estimated using soil moisture deficit index (SMDI) over a monthly time-scale. The deficit in soil moisture was calculated using soil water content in soil profile predicted by SWAT model. The result indicated that SDI has poor performance in predicting agricultural drought index. However, the outcome might be explained by the low temporal resolution of soil moisture data.

Spatial and Temporal Distribution of Pollution Based on Magnetic Analysis of Soil and Atmospheric Dustfall in Baiyin City, Northwestern China.

The characteristics of spatial-temporal distribution and sources for multiple environmental carriers (surface soil, soil profiles, atmospheric dustfall) from the typical industrial city of Baiyin in Northwestern China were studied by means of environmental magnetism. This study aims to contribute to the potential application of magnetic measurements in the case of multiple environmental carriers, for the evaluation and differentiation of urban pollution sources. Results show that background magnetic susceptibility of soil is 37 × 10−8 m3 kg−1, and that magnetite and hematite carry the magnetic properties. However, magnetic properties of urban soil and atmospheric dustfall are dominated by PSD magnetite. Magnetite content in soil samples is anomalously high surrounding metallurgical plant and slag dump (major industry district), of moderate value in the center of the city (major commercial district), and of low value in the west of city (Baiyin new zone). Vertical distribution of magnetite content in soil profile of waste land suggests that the pollutants are mostly enriched in the top 0–2 cm soil layers, while planting of crops near the industrial area may accelerate the transfer of contaminants deeper in the soil (2–30 cm); accordingly, reducing detrimental soil tillage practices can alleviate the vertical migration of pollution. Measurements of magnetic variations of atmospheric dustfall indicate that industrial emissions by factory chimneys and blowing dust from slag heap and mineral transport control the magnetic properties of dust, with slag heaps being the main pollution source since 2014. Governance of slag pollution is a primary task in resource-exhausted urban contexts. The combination of several magnetic parameters arising from multiple environmental carriers, such as soil and atmospheric dustfall, can provide comprehensive spatio-temporal information on environmental pollution.

Physico-chemical properties and distribution of nutrients in different type of calcareous vertisols

A survey work was conducted during summer season of 2013 in different type of calcareous soils from Raichur, Shahapur and Surpur (Sholapur) taluks and was investigated in order to provide detailed information on their physico-chemical properties and nutrients distribution. The clay content of slightly, moderately and strongly calcareous soils are relatively high (>40%). The average soil reaction from slightly, moderately and strongly calcareous soils 8.04, 8.47 and 8.43, respectively. These soils were slightly saline to saline and organic carbon for these soils remained low to medium. Average cation exchange capacity value was highest in strongly calcareous soils (67.85 c mol kg-1) followed by moderately (66.37 c mol kg-1) and slightly calcareous soils (56.18 c mol kg-1). The CaCO3 content variation in these soils may be due to parent material, native CaCO3 content in soil profile and arid and semiarid climate. The available nutrients like N, P, K, S and micronutrients are low in strongly calcareous soils followed by moderately and slightly calcareous soils. Available nutrients relatively high in case of slightly calcareous soils. Higher values of exchangeable Ca and Mg were recorded in strongly calcareous soils.

Determining the depth of mixing layer in which soil solute releasing from soil to surface runoff on the unsaturated loess slope under artificial rainfall condition

The mixing zone depth is a critical parameter in many popular agricultural non-point source pollution (NPS) models. Its variation for some special soil conditions and easily erosive region was limitedly studied. This study dealt with the extent of Br− releasing from soil to surface runoff, the actual mixing depth and the calculated one on the unsaturated loess slope, and the influences of soil initial moistures. Br− was placed as a tracer at different soil depths in the loess slope with three soil initial moistures. Br− concentration in surface runoff and soil profiles was monitored under simulated rainfall condition. The actual mixing layer depth was determined by whether Br− in that layer could be detected in surface runoff during the whole rainfall process. The average effective depth of interaction (EDI) was calculated by the confirmation method reported before. The shallower the application depth, the higher the Br− concentration and loss risk in surface runoff. The net loss rate had an exponential decreasing correlation with the solute-applied depth. The depth of Br− peak content in soil profile after the rainfall ended increased with the application depth. Br− concentration in the surface soil was more than that in the runoff at the end of rainfall, which indicated an incomplete mixing between runoff water and soil water in the mixing layer. Under this experimental condition, the actual mixing layer depth for 3.5% soil moisture slope was about 3 cm, that for 10% soil moisture was 6 cm or so, and that for 20% soil moisture was more than 7 cm. The average EDI calculated for 3.5, 10, and 20% soil moisture was 2.31, 3.76 and 4.95 cm, respectively, which were less than the actual mixing layer depth and more than some former studies. The traditional 1.0-cm mixing depth in many agricultural NPS models might not be so exact for some special region.

Exploring optimal catch crops for reducing nitrate leaching in vegetable greenhouse in North China

Chinese intensive greenhouse vegetable systems are characterized by high input of water and nutrients, which are not sustainable. There is an urgent need to explore smart and practical strategies to convert the “high input-low output” systems to “optimal input-output” ones. This study aimed to evaluate the effects of different catch crops on reducing nitrate leaching in the vegetable greenhouse during the summer fallow season. A two-year field experiment with three catch crops, i.e., sweet corn (SC), amaranth (A) and sweet sorghum (SG), and no catch crop (CK) were conducted in vegetable greenhouse in Dingzhou city, Hebei province, China. The measured soil water content and inorganic nitrogen (N) content in soil profile, biomass and crop N uptake were used to validate the WHCNS (Soil Water Heat Carbon Nitrogen Simulator) model, soil water movement and nitrate leaching were simulated. The results showed that the catch crops decreased the water drainage by 18.2–29.0% and nitrate leaching by 23.3–42.3% respectively, compared with CK. The water drainage reduction ranked as SC > SG > A, while the nitrate leaching reduction was A > SC > SG. The biomass was SC > SG > A, while the crop N uptake was SC > A > SG. Sweet corn could absorb the residual nitrate in the deep soil layers due to the long root system, while amaranth could absorb most residual nitrate in the surface soil. Amaranth showed greater N-uptake capacity than sweet corn, and the nitrate was mainly accumulated in the surface soil. Planting amaranth as summer catch crop reduced nitrate leaching in the vegetable greenhouses. Our study provides a guideline for selecting effective catch crops in intensive vegetable greenhouses in North China.

Trace elements in soils of oases of Enderby Land (on an example of Vecherny oasis)

The content of trace elements in the soils of the Vecherny Oasis (Enderby Land, East Antarctica), where the construction of the Belarusian Antarctic Station started in December 2015, is considered. The results of the research are based on data collected during four Belarusian Antarctic expeditions in the period from 2011 to 2017, and analytical testing of soil samples taken from impacted and non-impacted sites. A total of 22 soil samples were analyzed for the content of trace elements; to compare the levels of accumulation and possible migration pathways, 7 samples of bottom sediments were also analyzed. Determination of trace elements was carried out using the AAS method (Cd, Cr, Cu, Pb, Ni, Zn, Fe, Mn) and emission spectral analysis (about 40 elements). The average values and range of concentrations of trace elements in soils and bottom sediments of the oasis are presented. The possible dependence of the trace elements content on the location positions in the landscape and on the sources of impact is discussed. It is shown, that the variability of metals content in soil profile for background site is low. In comparison with other oases of Antarctica no hotspots have been revealed and no significant areas of soil contamination have been identified yet, which is largely due to the fragmentation of the soil cover and lack of significant sources of pollution.

STUDY THE EFFECT OF PARTIAL ROOTZONE DRYING IRRIGATION ON TOMATO CROP UNDER EGYPTIAN CONDITION

Agriculture is the main user of water, because the agriculture uses about 85% of available freshwater resources worldwide. This percentage will continue to be dominant in water consumption because of population growth and increased food demand. In Egypt, agriculture uses more than 80% of the available water. In irrigated agriculture, the right way to save irrigation water is to increase water use efficiency through better irrigation management (Toureiro et al., 2016).Water management is the most significant element to increase crop productivity. There is an urgent need to create strategies based on science and technology for sustainable use of water, including technical, agronomic, managerial, and institutional improvements (Jury and Vaux, 2007). Worldwide, tomato is the second most valuable vegetable crop next to potato (FAO, 2018). In Egypt, tomato is one of the leading vegetable in economic importance. The present study was conducted in the farm of the agriculture faculty, Menoufia University, Shebin EL-Kom during two growing seasons (summer season 2015 and winter season 2016). The main goal of this study was to investigate the effect of the partial rootzone drying irrigation on soil moisture, tomato yield and water use efficiency. The study was carried out to compare partial rootzone drying and the conventional irrigation under three levels of water application rate (100%, 75% and 50% of crop evapotranspiration, ETC), and covering conditions (covering and non-covering conditions). The partial rootzone drying irrigation and the covering condition increased the soil moisture content in soil profile, the percentage of marketable yield, and improved the water use efficiency compared with the conventional irrigation (CI) methods especially, when applying under deficit water application.

Characteristics of Water and Salt Transport in Layered Soils

Characteristics of water and salt transport in layered soils with the loess soil layer overlapping different particle size sandy soil layer, was investigated in two dimensions soil chamber. The results show that, finger flow occurs when the wetting front enters into the low layer sandy soil, and the accumulative infiltration is greater for coarser particle size sandy soil than that for finer particle size one. The behavior of water movement and salt transport are disagree since salt content in soil profile has a significant difference for two treatments and water content is almost same. The further analysis explains this phenomenon is mainly caused by adsorption of the finer sandy soil to Na+. In additional, Cl- is easier to movement in pathway of the finger flow than that of Na+ whether the soil texture was same or not.

Average concentration of soluble salts in leached soils inferred from the convective–dispersive equation

The convective-dispersive, or advective-dis- persive, equation (CDE) has long been the model of choice for solute transport in soils. Using the average concentra- tion of soluble salts in soil profile to evaluate changes in salinity due to irrigation can be beneficial when spatial variability of soil salinity at selected depths is larger than spatial variability of soil salinity in the layer encompassing these depths, and when soil salinity is evaluated with electric conductivity measurements that give layer-average rather than depth-specific salinity values. The objective of this work was to present analytical solutions of the CDE that express the average soluble salt content in soil profile as the function of time, water flux, and solute dispersion parameter. The solutions were developed for both semiin- finite and finite domain and implemented in a computer code. Examples are presented of using these solutions to develop a nomogram for the dispersion coefficient esti- mation and to evaluate the applicability of the semiinfinite domain solution to soil monolith leaching experiments. In cases when the CDE application is justified, the analysis of the salt leaching based on the average salt concentrations in soil profile provides estimates of the effective salt dis- persion parameter useful in land evaluation and soil

SWAT-MODFLOW 결합모형의 토양수-지하수 연결성 개선

This study presents the effects of temporally varied groundwater table on hydrological components such as surface runoff, evapotranspiration, and soil water content. To this end, the SWAT-MODFLOW model in which the groundwater module of SWAT is replaced with MODFLOW model has been used with a modification to enhance the coupling between the water content in soil profile and the groundwater in shallow aquifer. The variable soil layer construction technique (VSLT) is developed in the present work to represent the direct interaction of soil water and groundwater more realistically, and then the VSLT is incorporated into SWAT-MODFLOW model. In VSLT, when the simulated groundwater table rises within the soil zone, the soil layers below the water table is regarded as a portion of the shallow aquifer, so that those layers are excluded from the initially defined soil zone and are governed by the MODFLOW. From the simulation tests for the Musim river basin, the improved SWAT-MODFLOW model with VSLT is found to correctly evaluate the spatial distributions of overland flow, soil moisture, evapotranspiration according to the groundwater table variation.

Setpoints for Potato Irrigation in Sandy Soils Using Real-Time, Continuous Monitoring of Soil-Water Content in Soil Profile

ABSTRACT Adequate availability of water during the potato-growing season is critical for production of high yields of premium processing quality tubers. Real-time, continuous monitoring of soil water content in the soil profile can be used to optimize irrigation. In this study, capacitance probes were used for automated measurement of soil water content at 10, 30, 60, 90, and 120 cm depth in a Center Pivot irrigated potato (cv. Ranger Russet) field in a Quincy fine sand (mixed, mesic, Xeric Torripsamments). Depth integrated soil water content was calculated within the rooting depth (0–60 cm) and below the rooting depth (60–120 cm). Irrigation was scheduled to replenish either full evapotranspiration (ET), or 70% of ET (deficit irrigation). The soil water content at the 10 and 30 cm depth, as well as depth integrated soil water content in the 0–60 cm depth soil responded to each irrigation event. The “Full Point” and “Refill Point” for the soil within potato root zone (0–60 cm depth) were estimated to represent the maximum water holding capacity, and the soil water content at which irrigation is to be scheduled to avoid water stress, respectively. Depth integrated soil water content in the 0–60 cm-depth soil profile remained mostly above the Full Point during most of the growing season in the Full ET irrigation treatment, but remained within the Full Point and Refill Point for the deficit irrigation treatment.

Course of soil layer water content in agricultural cultivated soil during years 1999 and 2000

Water regime, which determines soil productive ability, depends on water inflow and outflow into or out of unsaturated soil zone. Soil as vital entity of the biosphere is not homogenous medium (Mikulec, 2004). Unsaturated soil zone is one of the most important and complicated part evaluated water movement in hydrologic cycle. The water supply in the unsaturated soil zone is directly influenced by a water transfer through its upper and lower boundary. The lower boundary is usually delimited by water groundwater table (Veliskovd et al. 2005). The upper boundary is the soil surface with or without plant canopy. It reacts directly on meteorological and climate conditions (Stehlovd, 2004). It is a place enabling the water inflow from precipitation into lower layers of a soil profile. Water store in unsaturated soil zone was determined by monitoring of water content in soil profile and groundwater tables in localities in region around Danube in Slovakia. The localities relate to agricultural cultivated soil. The aim of contribution is to estimate course of integral water contents in different layers of soil profiles at Slovakia localities near Danube (BaC and Cilifakd Radvafl)and to compare these actual integral water contents and integral water contents that are related to hydrolimits (Stekauerova et.al., 2002, Orfanus, 2005).