Loam Soil Texture Research Articles

The ecological and economic determinants of eastern redcedar (Juniperus virginiana) encroachment in grassland and forested ecosystems: A case study from Oklahoma

Frequent fires were used as a management tool to maintain prairies, savannas, and woodlands in the southern Great Plains of the United States. However, fire exclusion beginning in the mid-1900s allowed for the establishment and growth of fire-intolerant species such as eastern redcedar (Juniperus virginiana: ERC) beyond their naturally occurring habitats. Apart from the reduction in burning, wide soil and climate adaptability, and seed dispersal by birds have facilitated the expansion of ERC in the southern Great Plains. The encroachment of ERC has caused heavy ecological and economic losses to Oklahoma and thus has been a major management concern for the past few decades. This study utilized count data modeling to analyze USDA Forest Service's (USFS) Forest Inventory and Analysis (FIA) data to investigate the relationship between available ecological and economic factors and the abundance of ERC in grassland and forested ecosystems of Oklahoma. The results suggested that low site productivity, high basal area, dense canopy, and silt loam soil texture significantly increase the abundance of ERC on a given site. The results also indicated that the rate of ERC encroachment is 3.3% higher in the softwood and 2.0% higher in the miscellaneous forests, compared to the hardwood forests. However, the economic variables of the study such as ownership type, adoption of active management, and proximity to a metropolitan area did not show a significant relationship to the abundance of ERC.

Using polyacrylamide to control soil splash erosion in rainfalls with variable intensity and duration

Splash erosion is recognized as the first stage in soil erosion process and results from the bombing of the soil surface by rain drops. One of the soil erosion control methods is the use of chemical polymers. The purpose of this study was to investigate the effects of different rates of polyacrylamide - PAM (0, 2, 4 and 6 kg/ha) - on the rate of splash erosion at three rainfall intensities (60, 90 and 120 mm/h) and three rainfall durations (10, 20 and 30 minutes) in laboratory conditions using a FEL3 rainfall simulator and Morgan splash bowls on a marly soil with loam soil texture. In all three intensities, rainfall duration and PAM treatments, the reductions of erosion were significant at 99% level, while their interaction was not statistically significant. The results indicated that 2 kg/ha of PAM did not show any significant difference in splash erosion reduction for all the intensities and durations. Increasing the rate of PAM from 4 kg/ha to 6 kg/ha helped to reduce the splash erosion rate; however, there was not a significant difference between the rates of 4 and 6 kg/ha of PAM in the intensity of 90 and 120 mm/h. Most splash erosion reduction (54%) was obtained for the intensity of 60 mm/h and the duration of 10 min with 6 kg/ha of PAM.

Combined biochar and organic waste have little effect on chemical soil properties and plant growth

Biochar has received great attention as a soil conditioner since it can potentially sequester carbon (C) in soil, enhance soil physical, chemical and biological properties and improve crop productivity.</span></span><span lang="EN"> </span><span class="tlid-translation"><span lang="EN">This study reports the results of a pot experiment with olive (<em>Olea europaea</em> L.), carried out in an acidic and clay loam textured soil, and cultivated during two growing seasons under eight fertilization treatments. They included mineral fertilization equivalent to a rate of 100 kg ha<sup>-1</sup> of N, P<sub>2</sub>O<sub>5</sub> and K<sub>2</sub>O (NPK), biochar applied at a rate of 10 (B10), and at 20 (B20) t biochar ha<sup>-1</sup>, biochar-NPK mixture (B10+NPK), biochar-waste mixtures with mushroom waste compost (B10+MWC), olive mill waste (B10 + OMW), and municipal solid waste (B10+MSW), the organic materials applied at a rate of 20 t ha<sup>-1</sup>, together with a treatment without fertilization (control).</span><span lang="EN"> </span><span lang="EN">Biochar in the B20 treatment increased the soil C content in comparison to the control. Biochar in the B10+NPK treatment reduced soil nitrate levels compared to NPK treatment. No other benefits to soil properties, nutrient uptake or plant growth were observed with the use of biochar or any positive synergistic effect with the mixture of biochar with the other organic amendments. MSW, OMW and MWC tended to increase soil pH in comparison to the control.</span><span lang="EN"> </span><span lang="EN">Most of the studies with biochar were carried out in soils with edaphic limitations or harsh environmental conditions limiting plant growth, which may have facilitated the detection of favorable effects. Under less limited soils or stressful conditions for plants, such as the ones established in this experiment, the benefits of using biochar were poor.

Soil Amendment with Biochar Affects Water Drainage and Nutrient Losses by Leaching: Experimental Evidence under Field-Grown Conditions

Leaching of soluble elements from cultivated soils is a major concern to meet the target of agricultural sustainability in most areas. The effect of biochar application to a cultivated soil on water drainage and the consequent solute losses was assessed during a trial carried out over two consecutive growing seasons. Biochar was added to a loam-texture soil, at 0, 1, and 2% d.w. rates. A lysimeter-like set-up arranged in the experimental field-unit, allowed collecting the percolating water. Two multiple linear regressions (ANCOVA models) were applied to detect biochar effect on: (1) The seasonal amount of drained water; and (2) the concentration of solutes in the drained water. The statistical comparison among a set of slope coefficients as affected by treatments (growing season and biochar) was used as modelling approach. The lower biochar application rate (1%) significantly reduced both the amount of drained water and its concentration in solutes. Conversely, the higher biochar application rate (2%) showed no significant effects. Nitrate and chloride showed a significant interaction with biochar application rates. Higher biochar application increased nitrate leaching while reduced that of chloride. Biochar application within a rate no more than 1% resulted in a useful and quite effective technical operation.

Interrelationship between soil depth and soil properties of Pieniny National Park forest (Poland)

The purpose of this research was to investigate the relationship between soil biota such as microbial activity, soil fauna (e.g., earthworms and enchytraeids), and soil physical and chemical properties. The study area was located in Pieniny National Park (PNP) in the Carpathian Mountains in southern Poland. Soil samples were collected from six forest monitoring areas of PNP from two soil layers (at 0–15 cm and 15–30 cm down, respectively). The investigated soils were classified to eutric cambisols and had silt or silt loam soil texture. Upon analysis, soil aggregate stability index was connected with other physical, chemical, and biological soil properties. It was noted that the stability index of 3 mm to 5 mm soil aggregates influenced pH and dissolved organic carbon. The stability index of 2 mm to 3 mm soil aggregates was positively correlated with dissolved organic carbon, soil moisture, microbial biomass carbon, total organic carbon, total nitrogen, and enchytraeid density, and negatively correlated with bulk density, particle density, porosity, and permanent wilting point. The stability index of 1 mm to 2 mm soil aggregates was positively correlated with total nitrogen, enchytraeid and earthworm density and negatively correlated with particle density, porosity, and permanent wilting point. The study has shown what factors create a stable soil structure in the forest soils of PNP.

Effect of Ploughing Depth, Tractor Forward Speed, and Plough Types on the Fuel Consumption and Tractor Performance

Cost of fuel has a significant impact on the input costs of agricultural production, especially during primary tillage. It is affected by several parameters including tractor forward speed, depths of ploughing, and plough types. The experiment was performed in a Soil Hall at Harper Adams University, United Kingdom, in April 2015. A Massey Ferguson 8480 4WD tractor was used for investigating objectives of this study. The experiment was performed in a sandy loam soil texture at 11.73% soil moisture content and 1.35 (g/cm3) dry bulk density to study the amount of fuel consumption (l/ha) and the performance of tractor with effect of moldboard and disc ploughs as ploughs type, 15 and 20 cm as ploughing depth and 5 and 7 km/h as tractor forward speeds. The results showed that fuel consumption with a disc plough 5% was higher compared to the moldboard. Fuel consumption decreased approximately 8% when tractor at 7 km/h. Fuel consumption significantly decreased about 34% when ploughing depth increased from 15 to 20 cm. The power requirement to operate moldboard plough was higher by about 14% than a disc. The power requirement at speeds of 7 km/h was higher compared to the speeds of 5 km/h by about 27%. When the depth of ploughing increased from 15 to 20 cm, the power requirement increased by about 1.5%.

Influence of Boron Application on Root Growth of Green Gram in Loam Textured Soils

Boron (B) is one of the important essential plant micronutrient elements and plays a significant role in physiological and biochemical processes in the legumes and brassica crops. Some of the alkaline calcareous soils are B deficient soils. Root of the crop acts as zone of nutrient absorbing. On its growth and functioning, uptake of any nutrient takes place. A greenhouse experiment with green gram crop was designed to study the effect of B application on root in some alkaline calcareous loam textured soils for two years. Three soils with percent calcium carbonate content 0.75 (S I), 2.1 (S II) and 4.56 (S III) were collected from different sites of Ludhiana and Bhatinda districts, Punjab, India. The treatments comprised of four levels of soil applied B viz. 0.5, 0.75, 1.0 and 1.5 mg B kg-1 and two levels of foliar applied B viz. 0.1 and 0.2 percent borax solution with common control. Soil applied B had more influence on root mean dry matter yield than foliar applied B. Among all soil applied B, 0.5 mg kg-1 was best treatment. Soil applied B was more uptake by root as compared to foliar applied B. Among all three calcareous soils, Soil I with lower calcium carbonate was best soil in respect of root mean yield in comparison to Soil III with higher calcareous soils. At grand growth stage, the optimum yield (0.895 mg pot-1) was obtained when root B concentration was 10.6 mg kg-1 and the soil applied B level was 0.84 mg kg-1 while at maturity stage, the optimum yield (1.28 mg pot-1) was obtained when root B concentration was 10.6 mg kg-1 and the soil applied B level was 0.87 mg kg-1.

Performance of nitrification inhibitors with different nitrogen fertilizers and soil textures

AbstractNitrification inhibitors (NIs), DCD (dicyandiamide), and DMPP (3,4‐dimethylpyrazole phosphate), in combination with urea (UR) and ammonium sulfate nitrate (ASN) fertilizers were studied under contrasting soil textures (sand, loam, and clay) from cultivated soils collected in Brazil and Germany. Soil samples were incubated over 50 days and the content of ammonium ( ), nitrate ( ), and soil pH were measured periodically. Applied NIs delayed the nitrification process across all soil textures. Correlation analysis indicated that combining ASN with NIs resulted in higher content and efficiency in delaying the nitrification process with high N‐conversion rate (r = –0.82). The combination of ASN+ DMPP increased the efficiency of the N‐conversion rate (r = –0.86) due to H+ release in soil, while UR+DCD (r = –0.50) had an efficiency of the N‐conversion rate similar to UR (r = –0.42). All the NIs had a better performance in reducing formation in sandy soils as compared to the loam and clay textured soils. Use of DMPP with an N fertilizer results in a soil pH decrease and can be an option to increase the efficiency of the N‐conversion rate, reducing N losses in soil. Overall, our results suggest that NIs have a better performance in reducing formation in sandy soils as compared to that of the loam and clay textured soils. Use of DMPP with ASN results in a soil pH decrease and can be an option to reduce N losses in soil.

Determination of Optimal Irrigation Scheduling for Sesame (Sesamum indicum L.) at Dubti, Afar National Regional State of Ethiopia

Irrigation means applying adequate water at the right time to crops in the right amount. Irrigation timetable is essential for the development of best irrigated area management practices. A significant concern has become the sustainable use of water in agriculture. The adoption of irrigation water saving and the maintenance of acceptable yields could help preserve this ever more restricted resource In most cases, its humidity before and after irrigation has not been checked in Ethiopia. Although irrigation has been practiced for a long time, farmers have limited experience of this. It is therefore very important to monitor soil moisture levels for effective management of irrigation water. For three successive years, a field study was conducted to determine the optimum irrigation schedule for sesame production at Dubti. The study's goals were to evaluate the effect of different irrigation regime (different levels of depletion of soil moisture) on yield and efficiency of sesame adi variety use of water. The treatments were established based on the levels of depletion of soil moisture for sesame (MAD= 0.60). Five levels of depletion of soil moisture were then selected to evaluate the optimum irrigation schedule, namely SMD1 (60%), SMD2 (80%), SMD3 (100%), SMD4 (120%) and SMD5 (140% of the recommended value, 0.60). The result showed that SMD4 has increased the yield and water use efficiency of sesame on a sandy loam textured soil significantly (P < 0.05). Furthermore, the total requirement for crop water was 585.50 mm. However, the lower level of depletion of soil moisture below the recommended value (SMD1 and SMD2) resulted in lower efficiency of both yield and use of crop water. Keywords :Dubti, Irrigation scheduling, Sesame, Water use Efficiency. DOI : 10.7176/IEL/9-3-03 Publication date : April 30 th 2019

Optimized tuning of rosin adduct with maleic anhydride for smart applications in controlled and targeted delivery of urea for higher plant’s uptake and growth efficiency

Conventional urea is lost due to its high water solubility and microbial transformations which results low agriculture productivity and environmental pollution. To solve these problems, rosin adduct-coated controlled release urea fertilizer (RA-CRUF) was prepared. Properties of rosin adduct with maleic anhydride were optimized during synthesis by varying the reaction temperature (120, 140 and 160 °C), reaction time (2, 4, 6 h) and coating repeats (3, 6, 9 cycles). Twenty different rosin adduct compositions were coated by spraying of rosin adduct on urea to prepare RA-CRUF. The best optimized response of urea release for RA-CRUF was 510.00 mg L−1 in water at optimized values of coating repeats (6.79 cycles), reaction time (4.71 h) and reaction temperature (137.39 °C). The Fourier Transformed Infrared Spectroscopy confirmed the reaction of rosin with maleic anhydride at wavenumber 1780 cm−1 and 1856 cm−1 correspond to carbonyl of cyclic anhydride group. The optical microscopy analysis of surface and cross view of RA-CRUF showed a high homogeneity of coating surface. The cumulative urea release was 41.76% and 47.23% for RA-CRUF compared 100% and 82.6% for conventional urea in clay loam texture and loam texture soils respectively. RA-CRUF effect on growth performance of maize plant showed healthy growth and increase in chlorophyll contents up to 51.11 mg g−1 (clay loam texture soil) and 87.55 mg g−1 (loam texture soil).

Application of Phosphorus, Iron, and Silicon Reduces Yield Loss in Rice Exposed to Water Deficit Stress

Core Ideas Application of phosphorus, iron, and silicon was able to arrest the yield decline under water deficit stress. There was no significant interaction among phosphorus, iron, and silicon on grain yield. Application of these nutrients increased drought tolerance in plants. ABSTRACTA foremost challenge in rice (Oryza sativa L.) production is to identify suitable nutrient management strategy for reducing yield loss under water deficit stress (WDS) condition. This study investigated the interactive effects of water regime and nutrient management on grain yield and stress metabolites. Accordingly, a 2‐yr field experiment in factorial design with two levels of water management (i) well watered (WW; maintaining 5 ± 2 cm standing water) and (ii) water deficit stressed (WDS) to −60 kPa and two levels of supplementary P, Fe, and Si application was conducted. As compared to WW condition, WDS saved 52 and 46% irrigation water in 2014 and 2015 respectively, however the grain yield decreased by 32–34% under WDS as compared to WW. Application of P, Fe, and Si under WDS condition significantly increased grain yield by 7, 9, and 12%, respectively. Reduced relative water content and increased activity of osmolyte (proline) and antioxidant metabolites (catalase and peroxidase) due to application of P, Fe, and Si contributed to tolerate the WDS, which resulted in higher grain yield. Due to absence of significant interaction between P, Fe, and Si on grain yield, there was no significant advantage of application of more than one of these nutrients together. The results indicate that, application of P, Fe, and Si can increase rice grain yield and can reduce the yield loss under WDS as compared to WW condition in silt loam textured soil in Eastern India.

Performance of pyrazosulfuron-ethyl in non-puddled transplanted rainy season rice and its residual effect on growth of the succeeding crop in rice-wheat cropping pattern

A study was carried out in sandy clay loam textured soil of Mymensingh, Bangladesh to evaluate weed control efficiency of pre-emergence herbicide pyrazosulfuron-ethyl either alone or in sequential application with post-emergence herbicide in transplanted rainy season rice under non-puddled strip-tilled (NPST) field condition and also to examine the residual effect of those herbicides on germination and growth of the subsequently grown wheat crop. Five treatment combinations of pyrazosulfuron-ethyl were tested against one weedy check and one weed-free check. The study revealed that NPST rice field was mostly infested by grass and sedge weeds and herbicide treatments offered a wide range of control (above 50% to 95%) on all types of weeds. Application of pyrazosulfuron-ethyl followed by (fb) orthosulfamuron fb butachlor plus propanil provided the most effective and economic weed control over two years of the study. Moreover, micro-plot bioassay study claimed germination and growth of subsequently grown wheat were not adversely affected by herbicides that were applied in rice. Therefore, application of pyrazosulfuron-ethyl followed by post-emergence herbicide could be effective and economic to control weeds in NPST rice under rice-wheat system, but proper rate and time of application should strictly be followed.

Impacts of Cement Dust Deposition on Heavy Metal Pollution in Soil and Barley Crop Grown Around Abyssinia Cement Factory, Ethiopia

Different researches showed that cement manufacturing is one of the significant sources of heavy metal pollution in soil. In this study, heavy metals pollution in soil and barley crop grown around Abyssinia cement factory were investigated. A total of 36 soil samples and 22 barley sample were collected and analyzed at Holetta Chemistry Laboratory. The parameters analyzed in soil sample includes: Available heavy metals, total heavy metals and major physico-chemical properties. Dry ashing method was used to determine the level of heavy metals in barley sample. Analysis for the concentration of heavy metals were conducted using Atomic Absorption Spectrometer. One-way ANOVA were used to compare the mean values between experimental treatments with SPSS statistical software. The Geo-accumulation Index and transfer factor of each heavy metal were computed and interpreted. The Igeo values are below zero indicates that the soil quality is practically unpolluted. The results in soil physico-chemical properties showed that neutral to moderately alkaline soil pH, clay to clay loam soil texture, medium to high category of phosphorus, nitrogen, and potassium. The values of heavy metals transfer factors are below one indicates that the crop have not influenced by heavy metals that uptaked from cement dust polluted fields. The levels of heavy metals determined in the analyzed barley samples also found to be below the permissible limit set by FAO/WHO; hence, the concentration of these heavy metals in the barley crop analyzed, may not presently pose a health hazard and can as well serve as sources of essential trace metals to the population. Keywords : Heavy metals, Atomic Absorption Spectrometer, pollution indices, transfer factor DOI : 10.7176/CMR/11-2-01

Estimation of root zone soil moisture using passive microwave remote sensing: A case study for rice and wheat crops for three states in the Indo-Gangetic basin

This paper investigates estimation of root zone soil moisture using two passive microwave remote sensing datasets, Advanced Microwave Scattering Radiometer – 2 and Soil Moisture Active Passive satellites sensors. The study is focused on two crops, namely rice and wheat for the Indo-Gangetic basin, India, having a dynamic crop and soil type and land use land cover. A total of 21 rice crop and 23 wheat crop locations are chosen from the states of Uttar Pradesh, Madhya Pradesh and Bihar falling in the basin. The root zone soil moisture information is derived by estimating soil wetness index from surface soil moisture at 10 and 40 cm depths using a recursive exponential filter. The soil wetness index based algorithm is implementable even in the absence of ground information for a basin level study. The reference soil moisture dataset is obtained from the Global Land Database Assimilation System – NOAH at 10 and 40 cm depth. The research has also demonstrated significant potential of GLDAS-NOAH soil moisture data in the absence of ground (in-situ) soil moisture data.Of the various factors affecting surface and root zone soil moisture, this work evaluates the control of soil constituents on root zone soil moisture. The Spearman rank correlation coefficient is estimated for characteristic time delay with sand, silt and clay percentage at different locations. Coupling between and trends of surface and root zone soil moisture for rice and wheat crop locations are studied. The accuracy of estimated soil wetness index at 10 and 40 cm from two different satellite sensors at two different acquisition times (ascending and descending passes) is investigated by calculating the coefficient of determination, mean absolute error and mean biased error. This work highlights the significant difference in surface soil moisture estimation by two satellite sensors to derive root zone soil moisture for rice and wheat crops. Coefficient of determination is more (∼0.9) for SMAP derived soil wetness index whereas it is lower (∼0.65) for AMSR-2 derived soil wetness index for both crops. Characteristic time delay variation is observed at two different times and at both the depths, with characteristic time delay increasing with depth. Also, at the descending pass characteristic time delay is lower as compared to the ascending pass. A strong relationship between root zone soil moisture and soil texture is observed. For rice crop, a positive correlation with sand and clay is observed for Uttar Pradesh, Madhya Pradesh and Bihar locations having loam and sandy loam as the major soil class. And, for wheat locations, a positive correlation is observed for silt and clay for Uttar Pradesh locations and sand for Madhya Pradesh locations having loam and clay (light) soil texture. This work delivers essential information in understanding sustainable irrigation scheduling and increasing irrigation potential for rice and wheat crop locations. Having the knowledge of all the factors influencing crop cultivation and the derived root zone soil moisture, crop production can be optimized.

Effects of climate and soil properties on phytochemical characteristics of Ferulago angulate (Schltdl.) Boiss

This research investigated the effects of climate and soil on the content and components of essential oils in Ferulago angulate (Schltdl.) Boiss, belonging to the Apiaceae family. Aerial parts of plants were collected from three elevations (2500, 3000, and 3500 m above sea level) and three regions (Kallar Mountain from Boroujen, Mili Mountain from Koohrang, and Saldaran Mountain in Farsan, Chaharmahal and Bakhtiari province) with three replications. Results suggested that soil and climatic conditions had significant effects on the quantitative and qualitative properties of essential oils. The highest (0.65%) and the lowest (0.15%) levels of essential oils were obtained from elevation of Mountain Kallar (3000 m) and Mili Mountain (3500 m), respectively. Forty-four compounds were detected most of them being alpha-pinene, alpha-thujene, alpha-phellandrene, cis-ocimene, beta-phellandrene, beta ocimene, and nonadecane. As for regional variations, most of alpha-pinene (20.88%), betaocimene (6.8%), cis-ocimene (23.6%) were recorded in the elevation of 3000 m from Saldaran Mountain and alpha-thujene (10.14%), alpha-phellandrene (3.49%), nonadecane (5.01%), and beta-phellandrene (7.57%) were obtained in the elevation of 3000 m from Kallar Mountain in clay loam soil texture. The lowest values were obtained from elevations of 3500 m in each region especially in sandy clay soil texture in Mili Mountain. It seems that the greater amount of nutrients was due to the presence of clay-loam texture, and the less environmental stresses and desirable soil enrichment in this elevation led to an increase in the essential oils content and components of this plant.

Effect of Boron Supplement on Yield of Wheat Grown in Calcareous Soils of Different Textural Classes under Arid Conditions

Boron sufficiency supply to plant in calcareous soils of arid regions is severely reduced under arid climatic conditions. Therefore, this study was conducted to determine the effect of Boron (B) fertilization on yield of Wheat grown in calcareous soils of arid regions. Boron was added at two rates namely 0 and 0.5 mg B kg-1 soil to three most common textured class&amp;rsquo;s soils. Straw and grain yield was determined on oven dried basis. B content of plants was determined as well. Straw and grain yield of wheat was significantly increased by (67.0 and 87.1%), (24.5 and 82%) and (64.5 and 48%) under the addition of 0.5 mg B Kg-1 soil over that of no B addition to clay, loam and sandy loam soil, respectively. Results also showed that wheat grown on the coarse-textured soil had the least B uptake per pot compared to loam and clay textured soils. B content in straw and grain was increased by (77.4 and 121%), (81.2 and 157%) and (184 and 96.9%) under B addition compared to those of zero B addition to clay soil, loam soil and sandy loamy soil, respectively. Response to B addition, significantly, increased in all soils due to increase of available B content in soils which may suggest the importance of adding adequate rate of B application under cropping system of arid regions.

Impact of biochar coated with magnesium (hydr)oxide on phosphorus leaching from organic and mineral soils

PurposeRecent research suggests that Swedish organic arable soils have been under-recognized as a potential source of phosphorus (P) loading to water bodies. The aim of this study was to compare P losses through leaching from organic and high-fertility mineral soils. In addition, the effectiveness of a magnesium-salt-coated biochar applied below the topsoil as a mitigation strategy for reducing P losses was evaluated.Materials and methodsPhosphorus leaching was measured from four medium- to high-P arable soils, two Typic Haplosaprists (organic 1 and 2), a Typic Hapludalf (sand), and an unclassified loam textured soil (loam), in a 17-month field study utilizing 90-cm-long lysimeters. A magnesium-salt-coated biochar was produced and characterized using X-ray powder diffraction (XPD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and X-ray adsorption (XANES) spectroscopy, and its phosphate adsorption capacity was determined at laboratory scale. It was also applied as a 3-cm layer, 27 cm below the soil surface of the same lysimeters and examined as a mitigation measure to reduce P leaching.Results and discussionTotal-P loads from the 17-month, unamended lysimeters were in the order of organic 2 (1.2 kg ha−1) > organic 1 (1.0 kg ha−1) > sand (0.3 kg ha−1) > loam (0.2 kg ha−1). Macropore flow, humic matter competition for sorption sites, and fewer sorption sites likely caused higher P losses from the organic soils. Analysis by XRD and SEM revealed magnesium was primarily deposited as periclase (MgO) on the biochar surface but hydrated to brucite (Mg(OH)2) in water. The Langmuir maximum adsorption capacity (Qmax) of the coated biochar was 65.4 mg P g−1. Lysimeters produced mixed results, with a 74% (P < 0.05), 51% (NS), and 30% (NS) reduction in phosphate-P from the organic 1, organic 2, and sand, respectively, while P leaching increased by 230% (NS) from the loam.ConclusionsThe findings of this study indicate that P leached from organic arable soils can be greater than from mineral soils, and therefore, these organic soils require further investigation into reducing their P losses. Metal-enriched biochar, applied as an adsorptive layer below the topsoil, has the potential to reduce P losses from medium- to high-P organic soils but appear to be less useful in mineral soils.

Seeding Rate Influence on Rainfed Maize Grain Yield and Components in the Western Corn Belt

Core Ideas Maize seeding over 20,000 kernels ha–1 seldom increased yield in water‐limited western Nebraska. Increased seeding rate increased the number of ears m–2, which was compensated for by other yield components to reduce or maintain grain yield in western Nebraska. Primary yield components had greater effect than secondary yield components in water‐limted western Nebraska, compared with other studies under well‐watered conditions. Grain yield components were analyzed to determine the influence of seeding rate on maize (Zea mays L.) yield under rainfed conditions in the Western Corn Belt. The objectives were to compare maize yield and yield components at four seeding rates in Brule, Ogallala, and North Platte, NE, in 2012 and 2013. Research was conducted by planting multiple maize hybrids at 20,000 to 57,000 kernels ha−1. Grain yield, ears m−2, rows ear−1, kernels ear−1, kernels row−1, 100‐kernel weight, and bulk grain density were determined. Path and regression correlation analyses was used to understand yield determination with seeding rates, and determine yield component relative importance. Seeding rates &gt;20,000 kernels ha−1 only increased maize yield in one environment, whereas decreasing yield by approximately 1 Mg ha−1 in three environments. In the hot, dry 2012 growing season, ears m−2, kernels ear−1, and 100‐kernel weight had positive direct effects on yield for sites with silt loam and loam soil textures, but only the kernels ear−1 for the sandy soil site. In the higher rainfall environments of 2013, positive direct effect of ears m−2 with yield were present, but in the lower rainfall site, ears m−2 had negative direct effect with yield. Based on the magnitude of the direct effects, the yield component ears m−2 was most important for yield determination followed by the kernels ear−1, and lastly kernel weight. Maize should be planted at 20,000 kernels ha−1 in the Western Corn Belt to optimize grain yield and the number of ears m−2 produced.

A mechanical-dielectric-high frequency acoustic sensor fusion for soil physical characterization

The aim of this study was to develop a new soil multi-sensor fusion by combining mechanical, dielectric and acoustic responses in layered soils for estimation of soil water content, degree of compactness and texture. The load cell, dielectric and acoustic sensors were integrated on a 25 mm diameter, 45-deg conical probe. Functioning of the dielectric sensor is based on the fringe-field between the two adjacent ring electrodes. Passive acoustic responses (emissions) at high frequency (10–350 kHz) were measured using an acoustic emission (AE) piezo sensor during probe penetration into the layered soil. The AE sensor was installed inside the cone (close to the cone tip) to receive passive AEs originating at the cone-soil interface and between soil particles surrounding the moving probe. The multi-sensor probe was evaluated using laboratory vertical penetration tests in various layered soil columns consisting of three soil types: clay, loam and sand. Each soil texture was prepared at three soil water contents (0.4, 0.6 and 0.8 × lower plastic limit) and remolded at three bulk densities (1.25, 1.4 and 1.55 Mg m−3) in the column. The acoustic frequency distribution spectra clearly distinguished the sandy soil texture (irrespective of bulk density and water content) from the clay and loam soil textures, with a relatively poor discrimination between clay and loam soil. The results indicate that the dielectric sensor output is highly correlated to soil volumetric water content (R2 = 0.78, mean absolute error (MAE) = 0.025 m3 m−3) with a minor effect of bulk density. Data fusion of mechanical, dielectric and acoustic sensors significantly improved the measurement of soil water content (R2 = 0.93, MAE = 0.014 m3 m−3). Degree of soil compactness was well predicted from data fusion of the three sensors (R2 = 0.80, MAE = 3.32%). Therefore, the multi-sensor probe developed in this study is an economical and viable instrument that shows promising potential for in-situ use in soil physical characterization. Laboratory and field evaluations to further examine the sensor for practical applications, such as on-the-go soil physical sensing in precision agriculture, are needed.

Identification of Land Adequacy for Green Open Space Development area of Tanjung Barangan on the condition of land properties in Palembang

The city of Palembang is one of the cities that experienced rapid development and became the center of human activity. So that the expansion of the city to the periphery causes green open space reduction. The reduction of green open space inflicted the disruption of the balance between nature and human systems. Retention ponds include reduction of green open space border that serves as a drainage system so as to prevent flooding during the rainy season and maintain groundwater reserves during the dry season. This study aims to: 1) identify and evaluate the existing condition of soil properties (physical and chemical) in the green open space development area of Tanjung Barangan retention pond in plan area that will be functioned as a retention pond of Palembang City; 2) to see the relation between the physical and chemical of soil condition with the type of vegetation that will be developed in the area of green open space development plan; 3) recommend the appropriate vegetation types to be developed in the green open space development plan, retention pond area in Palembang City. This research used descriptive normative method and sampling was done by sample purposive sampling. The research was conducted in the administrative area of Palembang City, the sampling point was in the green open space development area of Tanjung Barangan retention pond in Bukit Baru Village, Ilir Barat 1 Subdistrict of Palembang City, there were 4 (four) research sample points. It can be concluded that based on the results of laboratory analysis and direct observation in the field, the condition of soil properties of green open space development plan area of Tanjung Barangan retention pond physically and chemically that was: average effective depth value belong to deep (&gt; 100 cm); soil texture of clay loam, clay and loam; platy and granular soil structures; soil color gray, yellowish brown to black; moderate to moderately rapid soil permeability; soil pH strongly acidic N-total low to moderate; Soil P2O5 is very low; K2O is very high; and C-organic is low to very high. Based on the results of the analysis, the recommendation of vegetation type from the Minister of Public Works Regulation No. 5 of 2008 showed that The Tanjung Barangan retention ponds contain 3 (three) types of vegetation recommended namely casuarina (Casuarina equisetifolia), coconut (Cocos nucifera) and fern tree (Filicium decipiens). While there were 4 (four) types of vegetation can be recommended with the condition of the soil management by calcification using agricultural lime, such as lime tohor (CaO), calcite (CaCO3) or dolomite (CaMg (CO3)2) which is munding rubber vegetation (Ficus elastica), mangosteen (Garcinia mangostana), bungur (Lagerstroemia speciosa) and resin (Agathis loranthifolia).