Cmolc Kg-1 Research Articles

Potentialities and limitations of Planosols with distinct depths of diagnostic horizon

There is a variation in the depth of subsurface horizon of Planosols in semi-arid region, which may influence the agricultural potential and affect food production. The general aim of this study was to identify potentialities and limitations of two Planosols as a function of subsurface horizon depth. The adjacent profiles P1 and P2 were studied in Pentecoste (Ceará, Brazil). Morphological, physical, and chemical analyses were done aiming at soil characterization. Soil bulk density (BD), porosity, and penetration resistance (PR) were analyzed in a completely randomized split-plot design with four replicates to compare P1 and P2 and the horizons Ap and Btf. Btf was found at 62cm depth in P1 and at 18 cm depth in P2. Indicatives of water saturation were more evident in P2. The profile P1 showed lower hardness and higher friability, as well as higher acidity in subsurface (pHH2O from 4.4 to 4.7) and higher aluminum content (1.2cmolc kg-1). Both profiles were eutrophic and showed low contents of organic carbon (1.5 to 8.5g kg-1) and phosphorus (0.9 to 3.9mg kg-1). The sodium percentage in CEC was 9.1% in P1 and 5.5% in P2. Water retention increases in Btf compared with Ap was 7.3% in P2 and 2.7% in P1. Both profiles showed increase in BD in Btf, reaching 1.7g cm-3, while PR was higher in P2 (1.5 MPa). There are potentialities and limitations common to both soil profiles, but P1 has more physical potentialities and more chemical limitations than P2.

Slow Pyrolyzed Banana Leaf Waste Biochar Amended Calcareous Soil Properties and Maize Growth

Background/objectives: Biochar has gained tremendous potential for mitigation of climate change and improving soil quality and productivity. This study aimed to develop biochar from banana leaves and evaluate its effect on soil properties and maize yield. Methods: Banana leaf-based biochar, prepared through slow pyrolysis (300-400 oC), was tested on maize crop in pot experiment using three biochar rates (B0 = 0 t ha-1, B1 = 20 t ha-1 and B2 = 40 t ha-1) along with a compost control (Bc = 5 t compost ha-1) and three chemical fertilizer (CF) rates (F0 = 0–Control, F1 = 120 kg N ha-1 and F2 = 120-90 kg NP ha-1) based on completely randomized design with three replications. Findings: The addition of banana leaf based amendments (BLBA) significantly improved soil properties except soil pH and EC. The application of higher biochar rate (40 t ha-1) revealed maximum soil CEC (23.65 cmolc kg-1), TOC (1.48%), TN (0.12%) and K (89.31 mg kg-1) while maximum P concentration (4.26 and 4.04 mg kg-1) was noted in NP and compost applied treatments. Likewise, higher biological (231.00 g pot-1) and grain yield (104.81 g pot-1) as noted in compost treatment, were at par with biochar rates of 20 and 40 t ha-1 which were due to improvement in nutrient uptake. Overall, higher rate of biochar (40 t ha-1) performed better over lower rate (20 t ha-1) and compost (5 t ha-1) in buildup of nutrients and improvement in soil properties. Applications/improvements: Therefore, lower biochar rate and compost of banana leaf origin with chemical fertilizers can serve as an alternate for maize nutrition and improvement in soil fertility and quality So, it is suggested that BLBA may be tested under long term field experiments on different crops. Keywords Banana leaves, biochar, calcareous soil, maize, nutrients, slow pyrolysis, yield

Effect of Salinization by NaCl on the Growth of African Palm (Elaeis guineensis Jacq)

It is necessary to know the effect of excessive salinity in the soil on the growth of the African palm crop. The objective of the work was to evaluate the effect of salinity caused by NaCl on the growth and absorption of nutrients in the oil palm crop in early growth stage. The research was carried out in the laboratories of the University of Cordoba, where the 16 kg experimental units were made up of a mixture of alluvium and rice husk in a ratio of 4: 1. A complete randomized design was used with six treatments and a control (0.0, 0.5, 1.0, 1.5, 2.5, 3.6, and 6.1 cmolc kg-1 Na) and four repetitions. The data were statistically analyzed by analysis of variance and regression. The results report that the salinity in the soil that originates with the application of 2.5 cmolc kg-1 of Na produces in the soil an electrical conductivity (EC) of 1.96 dS m-1. Consequently, a drastic reduction in the quantified biomass of dry mass of stem, leaf, roots, rachis and leaf area originates, and the models that express this trend were adjusted to decreasing linear regressions with their highly significant parameters. Salinity interferes with the absorption of nutritional elements, such as N, K+ and Mg2+, and foliar nitrogen is the nutrient with the highest sensitivity to variations in EC in the soil. Foliar phosphorus (P) and calcium (Ca) concentrations were not affected by salinity levels.

Application of Sub-bituminous Coal Activated with Urea to Improve Chemical Properties of Ultisols and Palm Oil's Growth (Elaeis Guineensis Jacq.) In Pulau Punjung, Dharmasraya

Ultisols are a type of suboptimal land with low fertility, so it is necessary to add ameliorants such as Sub-bituminous (unproductive young coal as an energy source) to increase soil fertility. This study aimed to examine the effect of Sub-bituminous coal activated by Urea in improving the chemical properties of Ultisols and the growth of oil palm. The study was conducted in Nagari Sungai Dareh, Pulau Punjung, Dharmasraya West Sumatra using a Randomized Block Design with 6 treatments and 3 groups. The treatments are the dose of Sub-bituminous coal (g (planting hole)-1) and Urea fertilizer, which is A = 150; B = 300; C = 450; D = 150 + 10% Urea; E = 300 + 10% Urea; and F = 450 + 10% Urea. The results showed that the administration of Sub-bituminous coal at a dose of 450 g (planting hole)-1 activated by 10% Urea was able to improve the chemical properties of Ultisols such as increasing the soil pH by 0.57 units; total-N by 0.13%; organic-C by 0.69%; available P by 3.25 ppm; CEC by 16,14 cmolc kg-1 and can reduce of Al-exch to immeasurable compared to 150 g (planting hole)-1. Sub-bituminous coal activated by 10% Urea increases oil palm growth (Elaeis guineensis Jacq.). Increasing plant growth was found in 450 g (planting hole)-1 + 10% Urea with an increase in plant height by 48.34 cm, the number of midribs of 4 strands, stem diameter by 1.71 cm, and nutrient plant of N, P and K by 0.014; 0.005; and 0.003%.

Fertilidad e índice de calidad del suelo de la cuenca del río San Pedro en Nayarit

El área agrícola de la cuenca del río San Pedro en Nayarit es una llanura costera con suelos de origen aluvial, sometidos a inundación, deposición y a diferentes procesos que controlan el aporte de nutrientes y la fertilidad del suelo. El objetivo de esta investigación fue evaluar las propiedades de los suelos para diagnosticar la fertilidad y determinar el índice de calidad del suelo, tomando como parámetros pH, MO, N, P, K, CIC, Ca y Mg. Se realizaron muestreos a 30 cm de profundidad en 38 sitios en junio de 2017 y en 45 en 2018. Se midió pH, CE, textura, Da, CO, MO, N inorgánico, P, CIC y bases intercambiables. Los valores promedio, máximo y mínimo fueron pH 5.78, 8.15 y 3.28; MO 1.58, 3.02 y 0.65%; N inorgánico 22.5, 43.6 y 3.5 mg kg-1; P Olsen 32.5, 67.4 y 1.4 mg kg‑1; K 0.45, 0.80 y 0.10 cmolc kg-1, respectivamente. La CE promedio fue 1.39 dS m-1 e indica que no existen problemas de salinidad. El 73% de los sitios fueron de textura arenosa a franco. El índice de calidad del suelo (SQI por su nombre en inglés) indica que la cuenca tiene un nivel de fertilidad medio, SQI promedio de 0.64; el 17% de los sitios tuvieron una fertilidad baja con pH entre 3.28-5.40, MO 0.81-1.20%, N 10-20 y P 5-10 mg kg-1; 42% media, pH 6.41-7.30, MO 2.01‑2.50, N 40-60 y P 15-20 mg kg-1; 36% moderadamente alta, y 5% alta con pH 8.20-8.80, MO 3.01-4.00, N 100-150 y P 25-35 mg kg-1. La distribución del SQI demuestra que en la llanura superior los suelos son de fertilidad baja a media, en la llanura intermedia y baja son de fertilidad media a alta, y en las partes de menor altura, la fertilidad está limitada por la interacción entre el sistema continental y el marino que salinizan los suelos.

Characterization of the Geophagic Materials and Their Associated Rocks and Soils from Anfoega, Ghana

This study was conducted to examine the physico-chemical and mineralogical properties of geophagic materials and their associated rocks and soils from Anfoega, Ghana. The geophagic materials were sampled from pits >10 m deep overlain by massive sandstones and shallow soils which were also sampled. The pH of the geophagic materials was strongly acid. The pH of the soils from the three sites was slightly to moderately acid, that of the fourth site was moderately acid in the surface but strongly acid in the lower layers. While the geophagic materials were enriched with clay, the soil samples contained high amounts of sand. The CEC of the geophagic materials (18.0 to 23.2 cmolc kg-1) was higher than that of the soils (5.3 to 22.6 cmolc kg-1). Thin sections of the rocks showed high amounts of quartz and accessory feldspars and sericite. The geophagic materials contained high amounts of clay (with >79% SiO2), quartz, feldspars and sericite. X-ray diffractograms of the geophagic materials, rocks and soils were dominated by quartz, kaolinite, muscovite and feldspars. The sialic minerals in the geophagic materials (shales) were probably leached from the overlying sandstones. The mineralogy of the soils indicated that they were formed in-situ from the underlying sandstones.

SPATIAL VARIABILITY OF SOME SOIL PROPERTIES IN SAHL AL-HUSSAINIYAH, SHARKIA GOVERNORATE, EGYPT

Sustainable soil management with appropriate understanding of soil characteristics is vital in maintaining and improving soil fertility. The objectives of thepresent study is to characterize the spatial variability across a soil for selected using GIS technique. A total of 120 geo-referenced representative soil samples (from 0 to 0.60 m depth) were collected from Sahl Al-Hussainiyah, Sharkia Governorate, Egypt. Analyses included pH,ECe, CaCO3, soil organic matter (OM), available N, P and K,cations exchange capacity (CEC) and bulk density (BD). Spatial distribution pattern varies from moderate to strong. The best fit semivariogram model of ECe, K and BD was stable model, whereas K-Bessel model was the best fit model of pH, OM and CEC.With the exponential model, the best fit was with CaCO3, N and P.According to the spatial distribution map, five zones were identified, where the study area was classified to 7.8 for pH, 11.5 dSm-1 for EC, 4.53% for CaCO3, 0.70% for OM, 62.6 mg kg-1 for N, 3.41 mg kg-1 for P. 132 mg kg-1 for K, 55.8 cmolc kg-1 for CEC and 1.52 Mg m-3 for BD. Thus, this methodology can be used succsseffly in Spatial Variability of some soil properties.

PENGARUH APLIKASI AMELIORAN DARI FORMULASI LIMBAH BATUBARA (FLY ASH DAN BOTTOM ASH) DAN SAMPAH PASAR DENGAN KAPUR TERHADAP pH, KTK DAN P TERSEDIA ULTISOL DAN GAMBUT

The formulation of coal waste (4 million t year-1) and market waste (175.000 t year-1) is a potential development of alternative ameliorant for marginal and swamplands. The purpose of this study was to examine ameliorant formulations from coal and market waste to improve pH, available P, and CEC of Ultisols and Peat. The step I of the study used a completely randomized design with 3 replications, namely A = coal waste (100 g); B = market waste (100 g); C = 1:1 (50 g : 50 g); D = 2:1 (66.7 g 33.3 g-1) and E = 1:2 (33.3 g 66.7g-1). The step II of the study used a completely randomized design with 3 replications in 3 formulations namely: A = best formulation (100 g); B = best formulation + 10% [Ca(OH)2] (10 g 100 g-1) and C = best formulation + 10% [CaMg(CO3)2] (10 g 100 g-1). The step III of the study used a completely randomized design with 3 replications namely: A = 0 t ha-1 (0 g 500 g-1 soil); B = 10 t ha-1 (2.5 g 500 g-1 soil); C = 20 t ha-1 (5.0 g 500 g-1 soil); D = 30 t ha-1 (7.5 g 500 g-1 soil); E = 40 t ha-1 (10.0 g 500 g-1 soil) and F = 50 t ha-1 (12.5 g 500 g-1 soil). The results of the study showed that application of ameliorant formulations from coal and market waste with 10% [CaMg(CO3)2] at 50 t ha-1 increased pH, available P and CEC of Ultisols and peat, respectively by 0.60 units, 2.11 ppm P and 10.83 cmolc kg-1 on Ultisols, and 0.33 units, 2.64 ppm P and 68.86 cmolc kg-1 in peat, compared to control.

Status and Changes in Chemical Properties of Upland Soil in Gangwon Province between 2001 and 2017

In order to obtain useful information for environment-friendly management of upland soils, the chemical characteristics of 170 upland fields in Gangwon province have been monitored every 4 years since 2001. In 2017, the pH, electrical conductivity (EC), organic matter (OM), and available phosphate (Avail. P2O5) of the soil samples were 6.4, 0.89 dS m-1, 32 g kg-1, and 742 mg kg-1, respectively. The values of exchangeable (Exch.) potassium (K), calcium (Ca) and magnesium (Mg) were 1.18, 7.6, and 2.0 cmolc kg-1, respectively. In terms of the long-term change, the contents of EC, OM, and Exch. cations in upland soils showed increasing tendency. However, significant changes in the contents of pH and Avail. P2O5 were not observed since 2013. The ratio of optimal range of pH and OM in upland fields reduced from 55% in 2001 to 36% in 2017 and from 33% to 27%, respectively. The ratio of excessive range of Exch. cations have increased. Therefore, it is necessary to apply the lime and fertilizers based on the soil test in order to properly manage the soil fertility of the upland soils. Meanwhile, average contents of Cd, Cu, Ni, Pb, Zn, and As were 0.23, 21.0, 13.5, 11.0, 82.6, and 4.8 mg kg-1, respectively. The results from the study imply that environment-friendly soil managements including the cultivation of green manure crop and application of organic composts are necessary to improve the soil chemical properties of upland fields. Excess, deficient and optimal range of chemical properties of upland soils in Gangwon Province (n = 170).

Potassium Mobility Potential of Forest Soil In Kurdistan Region, Iraq, As Estimated By Quantity- Intensity (Q/I) Relationships

This study aimed to assess potassium(K) 's potential mobility for some soils located in the Kurdistan Region of Iraq. Five soil samples were collected from a depth of (0-30) cm. For each sample, 5g of soil was equilibrated with 50 ml of 0.01 M CaCl2, amended with different K concentrations, and incubated for 24 h at 298 Kelvin. The supernatant was filtered, and K, Ca, and Mg were determined. Potassium exchange equilibrium was calculated from quantity-intensity (Q/I) isotherms. Mean AReK values for all studied soils ranged between 2.4x10-3 to 3.6x10-3(mol L-1)1/2, which reveals that K was preferentially held at inner potions. The amount of labile K(KL) ranged from 0.479 to 1.191cmolc kg-1 in studied soils. The highest value of KL was in Kanypanka while the lowest value was in Goizha. The potential buffering capacity (PBCK) was between 619.56 and 857.37 cmolc kg-1(mol L-1) -1/2. All studied soils were characterized by low percent K saturation and a high ability to replenish K concentration in the soil solution. Gapon selectivity coefficient was relatively high and ranged from 5.64 to 7.88 L mol-1. Higher values of KL indicate a greater K release into the soil solution. Such a high affinity of K to the solid soil phase was attributed to both the elevated organic matter content in these soils and their strong buffering capacities.

Corrección de la acidez del suelo: efectos en el crecimiento inicial del café.

La acidez del suelo ha sido considerada una limitante común para la producción de café en la mayoría de las regiones de Colombia. Esta investigación tuvo como objetivo determinar el efecto de la corrección de la acidez del suelo en el crecimiento inicial de café (Coffea arabica L.). Para cinco suelos representativos de la zona cafetera de Colombia y con valores de pH<5,2 se determinó el efecto de dosis crecientes de cal (0,00 1,25, 2,50, 5,00 y 10,00 g dm-3) en la biomasa seca total de las plantas, durante la fase de almácigo (seis meses). Con la aplicación de los tratamientos se logró corregir la acidez (pH y Al3+) e incrementar los contenidos de Ca2+ y Mg2+ en todos los suelos estudiados, presentando algunas variaciones entre estos. En tres de los suelos se presentó efecto de los tratamientos en la materia seca de las plantas, respuesta que se relacionó principalmente con el aumento del pH y la neutralización del Al+3. El mayor crecimiento de las plantas (rendimientos relativos entre el 95 y 100%) se asoció con los siguientes rangos de las propiedades e indicadores del suelo: pH 4,9-5,7, Ca2+ 5,1-11,2 cmolc kg-1, Mg2+ 0,9-2,1 cmolc kg-1, saturación de bases 21%-45%, Ca:Mg 4,4:1-7,4:1, Ca:K 7:1-37:1, Mg:K 1,4:1-4,8:1, Al3+ < 1,1 cmolc kg-1 y saturación de Al+3 < 12%.

Utilization of magnesium-rich synthetic gypsum as magnesium fertilizer for oil palm grown on acidic soil.

A study was conducted to determine the impact of applying different sources of Mg, namely kieserite, ground magnesium limestone (GML) and Mg-rich synthetic gypsum (MRSG) on an acid tropical soil, oil palm growth and production. Besides high amount of Mg and Ca, MRSG contains S. Exchangeable Ca in the untreated soil of the plantation was 0.64 cmolc kg-1, but its critical level to sustain oil palm growth was 0.9 cmolc kg-1. MRSG was applied in the plantation as Mg-fertilizer; however, since Ca is also a limiting nutrient, oil palm growth was correlated (r = 0.69) with Ca supplied by the MRSG. Mg needed to sustain oil palm production is normally supplied by kieserite. Its requirement can be met at a lower cost compared to that of the kieserite by using MRSG. Due to MRSG treatment, exchangeable Ca in the soil increased steadily to satisfy the requirement of oil palm for fruit bunches production. From the glasshouse and field study, it was observed that MRSG applied at 1.5 times the recommended rate gave results comparable to that of the kieserite. MRSG treatment resulted in the increase of soil pH to >5 that precipitated Al3+ as inert Al-hydroxides, which eventually enhanced oil palm seedlings growth. Thus, MRSG can also replace GML to increase soil pH and satisfy the Ca and Mg requirement of oil palm. It can be concluded that MRSG has the potential to be used as a source of Mg as well as Ca for oil palm grown on acidic soil.

Pedotransfer functions: the role of soil chemical properties units conversion for soil classification

Chemical soil analysis data can be expressed by weight (i.e., gravimetric basis) or volume (i.e., volumetric basis) of the fine earth (sieved ≥2 mm), resulting in different units, cmolc kg-1 and cmolc dm-3, respectively. The research problem is that the difference between methods to express the same soil properties hinders the comparison of results and database or dataset standardization. This paper aims to develop pedotransfer functions (PTF) to obtain the density of fine earth, which will then be used [...]

Changes in selected soil properties across a chronosequence of exclosures in the central dry lowlands of Ethiopia

In Ethiopia, rehabilitation of the natural resource-base in degraded lands through area exclosures has become a necessary intervention, albeit empirical studies on the impact of these exclosures are limited. This study was conducted to investigate changes in selected soil properties along exclosures’ age and slope positions in Kewet district, central dry lowlands of Ethiopia. Soil samples were collected from three slope positions of three purposively selected exclosures of 5, 15 and 20 years old and one adjacent open grazing land from 0-10 cm soil depth for analysis of pertinent soil properties. The effect of exclosure age on bulk density, contents of sand, clay, organic carbon, total nitrogen, available phosphorus, CEC, and exchangeable Mg+ and K+ was significant (P<0.05). All exclosures had low bulk density (1.14-1.16 g cm-3) as compared to the grazing land. Higher available water content (173 mm m-1) was recorded in the old exclosure. Soil organic carbon ranged from 2.58% (young exclosure) to 3.37% (middle age exclosure). Soil total nitrogen increased from 0.24-0.34%, while available phosphorus increased from 27-34%, from young to the old exclosure respectively. However, the influence of exclosures’ age on other soil properties was not significant. The young exclosure had the highest CEC (57 cmolc kg-1), whereas the grazing land had the highest total nitrogen and exchangeable Ca2+. From this result, it can be concluded that area exclosures, if managed properly, can improve some of the dynamic soil properties of open degraded grazing lands in the dry lowlands of Ethiopia.

Characterization of Biochar Produced from Different Feed Stocks

Imprudently disposed and burning of organic wastes have been causing environmental pollution and greenhouse gas emission. The objective of this study was to characterize the biochar produced from different agricultural wastes to explore its potential use as organic soil amendments. The feedstock derived from each of Eucalyptus globules (EG), Acacia decarance (AD), farm yard manure (FYM) and rice straw (RS) were collected and biochar was produced by slow pyrolysis at 300oC in the furnace. The determination of pH, carbon, phosphorus, cation exchange capacity, electrical conductivity and exchangeable basic cations of individual biochar was performed and statistical analyses carried out to compare the means values obtained. Higher carbon content was observed in biochar produced from AD (65.00%) compared with that of biochar produced from other feedstock types included in this study. pH value of Bbiochar produced from EG and RS were moderately acidic (pH 5.94) and neutral (pH 6.6), respectively, whereas biochar produced from AD (pH 8.07 and FYM (pH 8.17) revealed moderately alkaline pH level. High and low EC values were recorded in biochar produced from FYM (4.70 DS m-1) and the low value from EG (0.68 DS m-1), respectively. The maximum concentration of exchangeable magnesium (20.95%), potassium (16.40%) and sodium (1.77%), EC and phosphorous (2288.75 ppm) were testimony in biochar produced from FYM is potential to prove phosphorus fertilizer requirement of a crop but calcium (39.50%) was from biochar produced from AD. Higher CEC (129.75 cmolc kg-1) was detected in biochar produced from EG followed by biochar produced from RS (127.5 cmolc kg-1), AD (117 cmolc kg-1) and FYM (87.25 cmolc kg-1). Generally, the current finding revealed that biochar from different feedstock’s had different chemical properties, so this difference could contribute for soil fertility improvement as the result agricultural wastes is managed without pollution. But, the current work was limited to the characterization of biochar. So, more detailed investigation on the rate and reclaiming the power of the biochar and other issues should be investigated.

Variation in soil properties under different cropping and other land-use systems in Dura catchment, Northern Ethiopia.

There are limited reports about the impacts of long-term cropping and land-use systems (CLUS) on soil properties and nutrient stocks under smallholder farmers' conditions in developing countries. The objective of this research was to examine variation in soil properties and OC and TN stocks across the different CLUS in Dura sub-catchment, northern Ethiopia. Surveys and discussions on field history were used to identify nine CLUS, namely, tef (Eragrostis tef (Zucc) Trot)) mono-cropping (TM), maize (Zea mays L.) mono-cropping (MM), cauliflower (Brassica oleracea var. botrytis)-maize intercropping (IC1), red beet (Beta Vulgaris)-maize intercropping (IC2), cauliflower-tef-maize rotation (R1), onion (Allium cepa L.)-maize-onion rotation (R2), tr eated gully (TG), untreated gully (UTG), and natural forest system (NF). A total of 27 composite soil samples were randomly collected from the CLUS for soil analysis. Data were subjected to one-way analysis of variance and PCA. The lowest and highest bulk density was determined from NF (1.19 Mg m-3) and UTG (1.77 Mg m-3), respectively. Soil pH, EC and CEC varied significantly among the CLUS. The highest CEC (50.3 cmolc kg-1) was reported under TG followed by NF. The highest soil OC stock (175.3 Mg C ha-1) and TN stock (13.6 Mg C ha-1) were found from NF. The PCA chosen soil properties explained 87% of the soil quality variability among the CLUS. Such soil properties and nutrient stocks variability among the CLUS suggested that introduction of suitable management practices that sustain the soil system of the CLUS with poor soil properties and nutrient stocks are crucial for the study area conditions.

Studying Some Characteristics of Sandy Soil Amended by Water Hyacinth, Bean straw, and Compost

Two field experiments were carried at the Ismailia agricultural research station during the summer seasons of 2018 and 2019 to study some characteristics of sandy soil treated by three types of additives and cultivated by maize. Additives mixed with soil were the dried water hyacinth, straw of faba bean and compost each is loaded by 25, 50, and 100% of the recommended dose of nitrogen N and phosphorous P mineral fertilizers. Different treatments including control were distributed in a complete randomized block design with three replicates. Water holding capacity (%), field capacity (%), electrical conductivity (dSm-1), bulk density (g cm-3), cation exchange capacity (cmolc kg-1) and organic matter (%) content of soil before cultivation and after harvesting were estimated. Maize yield (kg ha-1) and some yield components were also calculated for different treatments. Results indicated that after harvesting, water-holding capacity (%) increased significantly by 20% using dried water hyacinth, non-significantly by 10 and 5% using bean straw and compost, respectively, compared to control at 100% NP application rate. Field capacity increased by 37.5% using dried water hyacinth and bean straw and by 12.5% using compost compared to the control. Non-significant change was observed in soil EC (dSm-1) neither before planting nor after harvesting. The application rate 100% NP showed the least bulk density values significantly decreased by 7.78% for compost, 4.44% for dried water hyacinth, and by 2.78% for bean straw compared to the control. At application rates 50 and 100% NP, compost treatments provided the maximum available P and K in soil followed by dried water hyacinth then bean straw. At application rate 100% NP, yield of maize dry matter (kg ha-1) significantly increased by 120.34, 116.96, 27.44% for dried water hyacinth, bean straw, compost, respectively. Seed yield (kg ha-1) increased significantly by 136.3, 135.85, and 33.63% for bean straw, dried water hyacinth, and compost, respectively.

LEAD REACTIONS IN SOME CALCAREOUS SOILS OF NORTHERN IRAQ

The adsorption experiment of three different calcareous soils (loam and clay) for Nineveh governorate (Tel Aakoub, Ibrahim Al-Khalil, and Taqlif) was classified under Aridsol-Calciorthids with a slight slant to alkaline (7.43), non saline (3.24 dS m-1), Low content of organic matter (17.3 gkg-1), cation exchange capacity (42 Cmolc kg-1), high content of carbonate minerals (409 g kg-1). Lead adsorption was studied by batch equilibrium method at a temperature of (298 Kelvin) for lead solutions (5,10,20,40,80,100 mg L-1). For 48 hours,the lead was measured in equilibrium solutions and the adsorption criteria were calculated according to Langmuir ,Freundlich and the DR equations. The results of the mathematical description of lead adsorption showed high efficiency in the use of Langmuir , Freundlich and the DR equations at the concentrations used. The lead added to the soil was also distributed between the equilibrium solution and the solid soil phase in terms of propagation coefficient values (Kd), which ranged from (111.8) to(255.5 l kg-1)with an average of 169 l kg-1. The DR equation exceeded the Langmuir and Freundlich equivalents in the description of lead adsorption to obtain the highest coefficient of determination (R2) and a lesser standard error (SE).The adsorption capacity (qm) of the lead ion in the study of soil was( 13.63 - 41.48 mol g-1).The K value associated with the adsorption capacity ranged from (-0.44) to (- 1.24) (mol2 KJ -2). The value of (E) is the free energy rate of the reaction ranged from the lead adsorption values (0.63 - 1.06 KJmol-1)

Relationship Mechanisms among Soils Fertility Degradation and Physicochemical Properties in Siwa Oasis Soils

The recent soil fertility evaluations are evidence of the serious development challenges that many agricultural regions in Egypt; and with growing food demand, soil evaluation will become even more important for the regions in the coming years. The soils studied revealed that the highest ions concentration measured in soil paste extracts were Na+ and Cl- ions. The soil pH could be categorized as slightly to moderately alkaline. Alkaline soils, that have ESP more than 15% and high pH values. In general, most soils were relatively sandy loam. Else, CEC of the soils in the study area was between 3.16 to 24.96 cmolc kg-1. Most soil study high content of CaCO3 and considered as very slightly; slightly; moderately and highly gypsiferous. Data indicated that the available macro and micronutrients in the study area are low. Also, the exchangeable cations were significantly affected by recently environmental changes. This study was undertaken to investigate the spatial variability of selected soil properties using SFI modeling. Up to on the quantitative evaluation of SFI using spatial variability of soil data and modeling techniques is a very important operation. SFI in our study area is very poor fertility (S4= <20) according to classes and values of SFI. Pearson correlation coefficient was calculated to determine the significant positive correlation among SFI and soil pH; EC; CaCO3; OM; total N; available of P, Fe, Mn and Cu; exchangeable of Ca, Na and K. In addition, the SFI is insignificantly and positively correlated with available Zn and exchangeable Mg.

Production of soybean and maize plants cultivated in acid soils with high contents of exchangeable aluminum

In several Brazilian acid soils, the extractable aluminum with the solution of 1.0 mol L-1 KCl (Al-KCl) may exceed 10 cmolc kg-1, but in some soils the presence of this element seems to exert little or no interference in the productivity of the plants. The study aimed to evaluate in which conditions the high levels of Al-KCl are related to the toxicity in soybean and maize plants cultivated in greenhouse, and their possible interference in the dry matter production of the same. Also, it aimed at assessing the soil chemical attributes that best identified a probable Al toxicity and the responses of the cultivated plants to liming. Al-KCl is not related to the manifestation of toxicity by the plants, nor did it interfere in the productivity of the plants cultivated in the AC9 and RS soils. On the other hand, the high levels of Al-KCl interfered in the productivity of these plants cultivated in the PE, BR and CB soils, manly in the treatments without limestone. Aluminum saturation, sum and base saturation were the best soil chemical attributes for the identification of Al toxicity and plant response to liming.