scholarly journals Efficiency of The Spaw Model in Estimation of Saturated Hydraulic Conductivity in Calcareous Soils

2020 ◽  
Vol 23 (2) ◽  
pp. 189-201
Author(s):  
Tariq H. Karim ◽  
Mohammed A. Fattah

The measurement of soil hydraulic properties is tedious, time-consuming, and costly. An alternative approach is to formulate models that utilize the physical and chemical properties of the soil as input variables to predict soil saturated hydraulic conductivity (Ks). However, the previous studies have not paid attention to the calcium carbonate content in their models; it can lead to reducing the size and number of the pores in the soil which, in turn, can lead to reduction Ks . Here we evaluated the ability of the Soil, Plant, Atmosphere, and Water (SPAW) model to predict Ks under different states of compaction for calcareous soils with wide-ranging textures sampled along a precipitation gradient in northwestern Iraqi Kurdistan. The results revealed that the best match occurred under loose to normal state of compaction for these soils. Among the soil properties, sand content was high significantly correlated with Ks followed by CaCO3, clay, organic matter content, silt and Electrical conductivity. A pedotransfer function (PTF) was proposed using these data and its results were compared to these from the SPAW model. Root mean square error (RMSE) and coefficient of variation (CV) for the comparison between measured Ks values and those predicted by the SPAW model were very high 2.7×10-4 cm s−1 and 166% respectively, that due to the values of Ks predicted by the SPAW model are overestimated for calcareous soils, for these reasons the accuracy of the SPAW model was improved via calibration. The RMSE and CV of the calibrated SPAW model were dropped to 9.8×10-5 cm s−1 and 61.2%, respectively. Additionally, the accuracy of our best PTF that constructed from sand, clay, and CaCO3 was slightly higher than the calibrated SPAW model. Therefore, it is recommended to use the calibrated SPAW model for predicting Ks in calcareous soils.

2016 ◽  
Vol 67 (1) ◽  
pp. 24-31 ◽  
Author(s):  
Grzegorz Jarnuszewski

AbstractPost-bog soils developed from limnic calcareous sediments are closely related to a young-glacial landscape and postglacial lakes in Northern Poland. The studies conducted in 2010–2012 on post-bog soils near lake Dubie (Równina Drawska, NW Poland), partially used as an arable land. The goal of research was to characterise some chemical and physical properties of post-bog soils developed from carbonate deposits near lake Dubie. The soils of the analysed area developed from lacustrine chalk and calcareous gyttja belong to black earth and mucky soils. Organic matter content in surface horizons ranged from 5.0 to 14.2%, content of CaCO3from 27.2 to 55.2%, the highest carbonate content was found in arable soil. The soils of the study area were characterised by a narrow C/N ratio, low level of total form of P and a high content of Ca. Specific density of surface horizons was in the range 2.49 to 2.58 Mg · m−3, bulk density from 0.445 to 1.212 Mg · m−3. High porosity was also found in the examined formations, from 0.826 in surface horizons and 0.700 m3· m−3in limnic deposits.


Author(s):  
Amita M Watkar ◽  

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.


2017 ◽  
Vol 2017 ◽  
pp. 1-16
Author(s):  
Kourtel Ghanem Nadra ◽  
Kribaa Mohammed ◽  
El Hadef El Okki Mohammed

Our objective is to study interaction between physical and chemical properties of soils and their earthworm community characteristics in different areas irrigated by wastewaters and well waters. The fields have different topography and agricultural practices conditions and are located in two regions of Batna department (Eastern Algeria). Both regions are characterized by a semiarid climate with cold winters and Calcisol soils. Nine fields were subject of this study. Three of these fields are located in Ouled Si Slimane region whose irrigation is effectuated by natural waters of Kochbi effluent. The other six fields are located at edges of Wed El Gourzi, effluent from Batna city, and partially treated through water treatment station. The best rates of water saturation and infiltration as well as abundance of earthworms were recorded at sites characterized by irrigation with wastewaters downstream of El Gourzi effluent. PCA characterizes two major groups: a group of hydrodynamic infiltration parameters and structural index stability of soil, explained by fields irrigated with wastewaters downstream of El Gourzi effluent. This group includes chemical characteristics: pH and electric conductivity. The second group is the characteristics of earthworms and includes organic matter content, active limestone levels, and Shannon Biodiversity Index.


2020 ◽  
pp. 124-132

An evaluation of the productivity of degraded alfisols at Makurdi and Otobi, Nigeria, using artificial desurfacing techniques (ADT) was carried out in 2012 and 2013 cropping seasons. The study was a split-split plot experiment arranged in a Randomized Complete Block Design with three replications. The soil was desurfaced at 0 – 5, 0 – 10, 0 – 15, 0 – 20 cm and the undesurfaced soil, 0 cm (control) depths. The restorative amendments were 9 t ha-1 of poultry dropping as an organic source of manure, N:P2O5:K2O as an inorganic source of manure and zero application as control. Soybean variety TGX 1448-2E and maize variety, Oba super II were used as test crop. Saturated hydraulic conductivity was significantly (P = 0.05) lower at 20 cm (29.08 cm hr-1 ), but did not differ significantly at 0 to 10 cm depths. Soil pH of 5.58 was recorded at 0 cm depth and it decreased to 5.05 at 20 cm depth. Also, organic matter content (1.71 – 1.00 g kg-1 ), total nitrogen (0.12 – 0.08 g kg-1 ) as well as CEC (7.39 – 6.24 cmol kg-1 ) recorded a significant decrease with increase in soil depth from 0 to 20 cm depths. Application of poultry manure increased total porosity and saturated hydraulic conductivity as well as organic matter content across desurfaced depths. Soybean number of leaves was significantly (P = 0.05) reduced at 4, 7, and 10 WAP with increased topsoil removal. The highest grain yield of soybean (1474 kg ha-1 ) was recorded on poultry manure treated plots which were significantly higher (p = 0.05) than other treatments. Application of poultry manure caused 20 % soybean yield reduction at 5 depth, and a 56 % reduction at 20 cm depth.


2014 ◽  
Vol 27 (1) ◽  
pp. 159-170 ◽  
Author(s):  
S. K. Hassan ◽  
E. M. Fadl-Allah

In the present paper forty-five zoosporic members of the aquatic fungi as well as some unidentified species belonging to seventeen genera were recorded <i>Nowakowskiella, Saprolegnia, Pythium, Rhizohlyctis</i> and <i>Achlya</i> were the most common genera of occurrence. Some physical and chemical properties of soil such as temperature calcium content total soluble salts and organic matter content are positively correlated with the of population zoosporic fungal.


Author(s):  
S. T. Patil ◽  
U. S. Kadam ◽  
M. S. Mane ◽  
D. M. Mahale ◽  
J. S. Dhekale

From the reviewed literature, it is observed that scientist’s worked on the various substrate medias used for hydroponic system. They also studied about different combinations of the media and their effect on crop growth. The reviewed literature shows that scientists have studied different organic and inorganic media viz. cocopit, saw dust, rice husk vermiculite, perlite, hydroton, pumice, sand etc. It was also found that these media are not easily, cheaply and locally available for users. Beside this, few scientists studied about physical and chemical properties of media such as particle size, porosity, bulk density, wettability, water holding capacity (WHC), Air filled porosity (AFP), Electrical conductivity, pH of these media. The crop specific suitability of combinations of the different media mixtures were also tested and reported by many scientists. It was revealed from reviewed literature that salinity of media caused linear reduction in the water consumption. The size and shape of particle size distribution are useful for estimating the hydraulic properties of the media The substrate under long cultivation period causes increase of organic matter content and microorganism activity which leads to an increased competition for oxygen in the root environment. The optimal EC levels range from 1.5 to 4.0 dSm-1 according to crop and its sensitivity to different salinity levels. It was also observed that level of growing medium temperature close to that of the surrounding air seems more suitable. The ideal substrate should have a total porosity of over 85 percent. Particles of smaller-sized individual grains have a larger specific surface area.


Author(s):  
E.O. Ogundipe

Soil properties are important to the development of agricultural crops. This study determined some selected soil properties of a drip irrigated tomato (Lycopersicon esculentum M.) field at different moisture regime in South-Western Nigeria. The experiment was carried out using Randomized Complete Block Design with frequency and depth of irrigation application as the main plot and sub-plot, respectively in three replicates. Three frequencies (7, 5 and 3 days) and three depths equivalent to 100, 75 and 50% of water requirement were used. Undisturbed and disturbed soil samples were collected from 0-5, 5-10, 10-20 and 20-30 cm soil layers for the determination of some soil properties (soil texture, organic matter content, bulk density, infiltration rate and saturated hydraulic conductivity) were determined using standard formulae. Soil Water Content (SWC) monitoring was conducted every two days using a gravimetric technique. The soil texture was sandy loam for all the soil depths; average value of soil organic matter was highest (1.8%) in the 0-5 cm surface layer and decreased with soil depth; the soil bulk density value before and after irrigation experiment ranged from 1.48 and 1.73 g/cm3 and 1.5 and 1.76 g/cm3, respectively; there was a rapid reduction in the initial infiltration and final infiltration rate. Saturated hydraulic conductivity show similar trend although the 20-30 cm layer had the lowest value (50.84 mm/h); the SWC affect bulk density during the growing season. The study showed that soil properties especially bulk density and organic matter content affect irrigation water movement at different depth..


1998 ◽  
Vol 13 (3) ◽  
pp. 132-137 ◽  
Author(s):  
Roger Lalande ◽  
Valentin Furlan ◽  
Denis A. Angers ◽  
Gilles Lemieux

AbstractWood residues are applied to soils to improve their organic matter content and related biological, physical, and chemical properties. We monitored the changes in soil total C and N content, the bacterial, fungal and actinomycetal populations, and microbial biomass and activity during 20 weeks in the first season following the application of chipped wood from twigs (CWT), and as residual effects during the second growing season on a loamy soil (coarse loamy, mixed, frigid, Humic Fragiorthod) in Sainte-Brigitte-des-Saults (Québec) Canada. Wet-aggregate stability and the content of nutrients of the soil also were determined. Adding CWT stimulated the bacterial and actinomycetal populations very rapidly (within 8 weeks); in the second season the effect was less pronounced and gradually disappeared. The most significant and long-lasting effect was on the fungal population in two consecutive years of observation, with increases of up to 24-fold. This stimulation of fungi possibly was responsible for the large and significant increase in wet-aggregate stability observed in the second year. The effect of CWT on alkaline phosphatase activity and total C and N was observed only in the second season. Someimmobilization was seen only in the season immediately following residue application. The addition of the CWT also supplied micronutrients, in particular Zn, which would make it a useful source of some elements in deficient soils. Application of CWT to this soil greatly improved its quality, as revealed by its biological, chemical, and physical attributes.


Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 120-126 ◽  
Author(s):  
G. W. Harrison ◽  
J. B. Weber ◽  
J. V. Baird

Preemergence applications of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], chloramben (3-amino-2,5-dichlorobenzoic acid), fluometuron [1,1-dimethyl-3-(α,α,α-trifluro-m-tolyl)urea], propachlor (3-chloro-N-isopropylacetanilide), and trifluralin (α,α,α-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine) were compared in 10 North Carolina soils and the relationship of activity to soil physical and chemical properties appraised. Oats (Avena sativaL. ‘Carolee’) were used as the indicator plant in bioassays under greenhouse conditions. Fifteen soil properties were measured and correlated with herbicide I50(50% fresh weight inhibition) values. Organic matter was the soil variable most highly correlated with herbicide phytotoxicity. There was an inverse relationship between herbicide water solubility and inactivation by organic matter. Volume weight determinations and water holding capacity values (0.1 bar) provided relatively good estimates of soil organic matter contents, but were not as highly related to herbicide activity as organic matter content.


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