Showing papers in "Archives of Agronomy and Soil Science in 2012"
TL;DR: In this article, the effect of exogenously applied silicon (Si) on the growth and physiological attributes of wheat grown under sodium chloride salinity stress was investigated in two independent experiments.
Abstract: We investigated the effect of exogenously applied silicon (Si) on the growth and physiological attributes of wheat grown under sodium chloride salinity stress in two independent experiments. In the first experiment, two wheat genotypes SARC-3 (salt tolerant) and Auqab 2000 (salt sensitive) were grown in nutrient solution containing 0 and 100 mM sodium chloride supplemented with 2 mM Si or not. Salinity stress substantially reduced shoot and root dry matter in both genotypes; nonetheless, reduction in shoot dry weight was (2.6-fold) lower in SARC-3 than in Auqab 2000 (5-fold). Application of Si increased shoot and root dry weight and plant water contents in both normal and saline conditions. Shoot Na+ and Na+:K+ ratio also decreased with Si application under stress conditions. In the second experiment, both genotypes were grown in normal nutrient solution with and without 2 mM Si. After 12 days, seedlings were transferred to 1-l plastic pots and 150 mM sodium chloride salinity stress was imposed for 10 day...
74 citations
TL;DR: The importance of soil organic matter (SOM) over the past two centuries has been investigated in this article, where the importance of the SOM stock has been analyzed in terms of its importance in food, fiber, wood, and biofuel production.
Abstract: The theories about plant nutrition and soil fertility varied widely from the antiquity to the middle of the nineteenth century, with major (Thaer A. 1809. Grundsatze der rationellen Landwirtschaft (1809–1812). Berlin (Germany): Realschulbuch Ed.) or minor (Liebig J. 1840. Die organische Chemie in ihrer Anwendung auf Agrikultur und Physiologie. Braunschweig (Germany): Vieweg) importance attributed to soil humus or soil organic matter (SOM). The importance assigned to humus over the past two centuries will be developed in this historical paper. Intensification of agriculture in the twentieth century permitted an important increase in cultivated plant yield of food, fiber, wood, and biofuel production, not only in the northern countries, but also in some southern countries (e.g., India and China) with the emergence of the Green Revolution. However, the question of organic restitutions and the maintenance (or increase) of the SOM stock was, at times, not taken into consideration; consequently, there was a gen...
72 citations
TL;DR: In this article, four different methods for reference crop evapotranspiration (ET0) were calibrated and validated for estimation of daily to mean monthly ET0 by weighing lysimeter data during 2005-2006 and 2004-2005, respectively, in a semi-arid region.
Abstract: In this study, four different methods for reference crop evapotranspiration (ET0) were calibrated and validated for estimation of daily to mean monthly ET0 by weighing lysimeter data during 2005–2006 and 2004–2005, respectively, in a semi-arid region. The value of the constant in the Hargreaves–Samani method changed from 0.0023 to 0.0026 for daily to mean monthly ET0, and can be used in stations with only air temperature data. The constant of the aerodynamic resistance equation in the FAO-56 Penman–Monteith method (208.0) changed to 85.0. The value of coefficient a in the FAO-24-Radiation method was between −0.5 and −0.67. Further, the empirical equations were modified to estimate the value of b in the FAO-24-Radiation method and C in the FAO-24 corrected Penman method. The results showed that the modified FAO-56, corrected Penman–Monteith and FAO-24-Radiation methods are the most appropriate for estimating daily to mean monthly ET0. Furthermore, the modified FAO-24 corrected Penman method was ranked in f...
63 citations
TL;DR: In this article, the consequences of switching growing of rice from flooded to aerobic conditions on soil fertility and its management are analyzed, and it is shown that the fertility problems under aerobic rice are better addressed with the cro...
Abstract: The lowland rice system in Asia makes a major contribution to the global rice supply and is often cited as an example of a sustainable system in which two or three crops of rice are grown in sequence under submerged conditions. However, water shortages are becoming critical in some regions for lowland rice cultivation; and there is high potential in exploring rice cultivation under moisture regimes that save water and also increase productivity. The objective of this article therefore is to analyze the consequences of switching growing of rice from flooded to aerobic conditions on soil fertility and its management. Fertility advantages of submerged rice include amelioration of chemical fertility, preferential accumulation of organic matter and improved availability of major, secondary and selected micronutrients, which contribute to the long-term maintenance of soil fertility and sustainability of the lowland rice system. However, the fertility problems under aerobic rice are better addressed with the cro...
53 citations
TL;DR: In this article, a drought stress was imposed on four varieties of wheat (Triticum aestivum L.), Mohan Wonder (MW), Kedar (K), Gayetri (GY), and Gandhari (GN), for 3, 6 and 9 days.
Abstract: Drought stress was imposed on four varieties of wheat (Triticum aestivum L.), Mohan Wonder (MW), Kedar (K), Gayetri (GY) and Gandhari (GN), for 3, 6 and 9 days. The activities of all five tested antioxidative enzymes, peroxidase, ascorbate peroxidase, catalase, glutathione reductase and superoxide dismutase, were enhanced initially in varieties K and GN, whereas in MW and GY, catalase and superoxide dismutase showed a decrease in activity at all periods of drought stress. Peroxidase and glutathione reductase activities increased even on the ninth day of stress in K and GN, but all other activities showed a decrease after 3 days of stress. H2O2 accumulation increased with drought stress, but in K and GN there was decrease during prolonged drought stress. Lipid peroxidation increased significantly due to drought stress, which was higher in the case of MW and GY. Proline, phenol and ascorbate content increased with period of drought stress. Carotenoid accumulation also increased initially. Total chlorophylls...
46 citations
TL;DR: In this paper, a site-specific nutrient management (SSNM) has been found especially useful to achieve the goals of improved productivity and higher N use efficiency (NUE) in rice and wheat.
Abstract: Among plant nutrients, nitrogen (N) is the most important. Its importance as a growth- and yield-determining nutrient has led to large and rapid increases in N application rates, but often with poor use efficiency. Nitrogen management requires special attention in its use so that the large losses can be minimized and the efficiency maximized. Site-specific nutrient management (SSNM) has been found especially useful to achieve the goals of improved productivity and higher N use efficiency (NUE). Leaf color charts and chlorophyll meters assist in the prediction of crop N needs for rice and wheat, leading to greater N-fertilizer efficiency at various yield levels. Crop simulation models can be used in combination with field information and actual weather data to make recommendations to achieve higher NUE. Remote sensing tools are also used to predict crop N demands precisely. At the same time, traditional techniques like balanced fertilization, integrated N management (INM), use of nitrification inhibitors a...
45 citations
TL;DR: In this paper, a field experiment was carried out in 2006-2007 to determine the impact of zeolite on nitrogen leaching and canola production, and the results demonstrated that the highest growth parameters and seed yield were attained with 270 kg N ha−1 and 9 t Z−1.
Abstract: With regard to the low cation-exchange capacity and large saturated hydraulic conductivity of sandy soils, a field experiment was carried out in 2006–2007 to determine the impact of zeolite on nitrogen leaching and canola production. Four nitrogen (N) rates (0, 90, 180, and 270 kg ha–1) and three zeolite amounts (3, 6 and 9 t ha−1) were included as treatments. The results demonstrated that the highest growth parameters and seed yield were attained with 270 kg N ha−1 and 9 t zeolite ha−1. However, the highest and the lowest seed protein percentage and oil content were obtained with 270 kg N ha−1 accompanied by 9 t zeolite ha−1, respectively. Nitrate concentration in drained water was affected by nitrogen and zeolite. The lowest and highest leached nitrate values were found in control without N and zeolite (N0Z0) and in treatments with the highest N supply without zeolite (N270Z0), respectively. In general, nitrogen-use efficiency decreased with an increase in N supply. Application of 9 t zeolite ha−1 showe...
45 citations
TL;DR: In this article, the average percentage increase in K fixation with increasing residence time was 79 and 56% for surface and subsurface soil, respectively, for both surface and sub-surface soil.
Abstract: Potassium fixation capacity and mineralogical analysis of 24 representative soils, collected from southern Iran, were studied. Potassium fixation analysis was performed by adding six rates of K from 0 to 1000 mg kg−1 soil in a plastic beaker and shaking for 24 h. Mineralogical analysis showed that the clay fractions were dominated by smectite, chlorite, mica, palygorskite, vermiculite and quartz. In general, the studied soils fixed 8.5–55% of the added K. The potassium fixation capacity of the studied soils was significantly correlated with smectite content (r 2 = 0.87), clay content (r 2 = 0.60), cation-exchange capacity (r 2 = 0.79) and NH4OAc-K. Wetting and drying treatment and incubation time had significant effects on K fixation. The average percentage increase in K fixation following the wetting and drying treatment was 24 and 30% for surface and subsurface soils, respectively. The average percentage increase in K fixation with increasing residence time was 79 and 56% for surface and subsurface soil...
40 citations
TL;DR: A field experiment was conducted in Navsari, India during 2003-2007 on a Vertisol to evaluate the productivity, sustainability, resource-use efficiency and economics of 10 rice-based cropping systems as mentioned in this paper.
Abstract: The continuous growing of rice has led to a deterioration in soil quality, resulting in a serious threat to agricultural sustainability in the high rainfall zone of south Gujarat, India. Therefore, crop diversification with a wider choice in the production of crop varieties is being promoted to restore the soil quality. A field experiment was conducted in Navsari, India during 2003–2007 on a Vertisol to evaluate the productivity, sustainability, resource-use efficiency and economics of 10 rice-based cropping systems. The results showed that system productivity for rice–fenugreek (Trigonella foenum-graecum)–okra (Abelmoschus esculentus) was highest (25.73 t ha−1), followed by rice–onion (Allium cepa)–cowpea (Vigna sinensis L.) (24.15 t ha−1); and the lowest system productivity was observed with the rice–wheat (Triticum aestivum)–fallow system (7.85 t ha−1). The sustainable yield index (0.97), production efficiency (102.94 kg ha−1 day−1) and field water use efficiency (15.98 kg ha−1 mm−1) were maximum with ...
39 citations
TL;DR: Sunflower genotypes Sin-Altheeb and Coupon appeared to inhibit total weed number and biomass more and significantly increased wheat yield compared with the least-suppressive genotypes (Euroflor and Shumoos).
Abstract: Studies were conducted to screen eight sunflower (Helianthus annuus L.) genotypes for their allelopathic potential against weeds and wheat crop, which customarily follows sunflower in Iraq. All sunflower genotypes significantly inhibited the total number and biomass of companion weeds and the magnitude of inhibition was genotype dependent. Among the eight genotypes tested, Sin-Altheeb and Coupon were the most weed-suppressing cultivars, and Euroflor and Shumoos were the least. A subsequent field experiment indicated that sunflower residues incorporated into the field soil significantly inhibited the total number and biomass of weeds growing in the wheat field. Sunflower genotypes Sin-Altheeb and Coupon appeared to inhibit total weed number and biomass more and significantly increased wheat yield compared with the least-suppressive genotypes (Euroflor and Shumoos). Chromatographic analyses by HPLC revealed the presence of 13 secondary metabolites in residues of the tested sunflower genotypes. All the isola...
38 citations
TL;DR: An overview of the interactions between the microflora and crop, with emphasis on nutrient transformations in the rhizosphere, is provided so as to develop effective and efficient environmentally sustainable strategies for this crop.
Abstract: The sustainability of rice production systems globally is intricately related to the chemistry, physics and biology of rice soils – with basic properties differing considerably in wet/dry land soils, tropical/temperate areas or even with the soil surface or rhizosphere niche of the field. Rice fields represent unique aqua-terrestrial ecosystems in which the tremendous diversity of soil microbes, soil fauna and plants – ranging in function from nitrogen fixers, nitrifiers, methanogens, methane oxidizers, phosphate-dissolving microbes, sulfur oxidizers to catabolizers of pesticides is observed. This diversity is inclusive of bacteria, cyanobacteria, archaea, planctomycetes and β-proteobacteria, besides the increasing members of endophytes associated. The complexity and dynamic nature of this ecosystem requires in-depth investigations of the tripartite interactions among plants, microbes and the soil–water environment. This needs to be complemented with studies on the ecological compartmentalization due to d...
TL;DR: The Muencheberg Soil Quality Rating (MQR) as discussed by the authors is an indicator-based straightforward overall assessment method of agricultural soil quality and crop yield potentials consistently over a range of spatial scales.
Abstract: This paper provides information about a novel approach of rating agricultural soil quality (SQ) and crop yield potentials consistently over a range of spatial scales. The Muencheberg Soil Quality Rating is an indicator-based straightforward overall assessment method of agricultural SQ. It is a framework covering aspects of soil texture, structure, topography and climate which is based on 8 basic indicators and more than 12 hazard indicators. Ratings are performed by visual methods of soil evaluation. A field manual is then used to provide ratings from tables based on indicator thresholds. Finally, overall rating scores are given, ranging from 0 (worst) to 100 (best) to characterise crop yield potentials. The current approach is valid for grassland and cropland. Field tests in several countries confirmed the practicability and reliability of the method. At field scale, soil structure is a crucial, management induced criterion of agricultural SQ. At the global scale, climate controlled hazard indicators of ...
TL;DR: In this paper, the effect of the addition of barley straw on a loam soil was observed over a two-month period: soil properties were measured weekly to determine whether the presence of additional organic residues induced a...
Abstract: Organic matter plays an important and multi-faceted role in soil. Physically, organic matter influences soil structure and all associated properties. Chemically, soil organic matter affects the cation exchange capacity and the capacity for buffering changes in soil pH. Biologically, organic matter acts as the nutrient and energy supply for microbial biomass and higher plants. A soil which is biologically and chemically fertile but which cannot physically support crop development will not fulfill its agronomic potential. Soil productivity is, therefore, determined by a combination of organic matter's influence on physical, chemical, and biological soil properties. It has been shown that the incorporation of crop residues into soil is beneficial to soils, improving one or more essential soil attributes. The effect of the addition of barley straw on a loam soil was observed over a two-month period: soil properties were measured weekly to determine whether the presence of additional organic residues induced a...
TL;DR: In this paper, the potential of glauconitic sandstone as a fertilizer for supplying potassium to plants was evaluated by using X-ray fluorescence analysis of 2.24% potassium oxide plus high contents of silicon, aluminum and ferric oxide.
Abstract: This study evaluated the potential of glauconitic sandstone as a fertilizer for supplying potassium to plants. The glauconite sandstone (Maraveh, Iran), as analyzed by X-ray fluorescence, was composed of 2.24% potassium oxide plus high contents of silicon, aluminum and ferric oxide. One-year old olive trees, Olea europaea L., were grown in sand or hydroponic culture in a greenhouse under three potassium treatments. Modified Hoagland nutrient solutions based on potassium treatments including 0.5 mM K+, 5 mM K+ and 400 g glauconitic sandstone powders (per 10 L in hydroponics and per 2.5 L in sand instead of K+ supply) were used in both cultures. Plants grown under the three different potassium treatments did not show any potassium deficiency symptoms. In the sand culture, growth and potassium content were higher in plants fed with 5 mM potassium than with the other two potassium treatments. Growth retardation and decreased potassium content in plants fed with 0.5 mM potassium were more severe in the hydropo...
TL;DR: In this paper, the effect of permanent cover crops with resident vegetation on labile organic matter fractions and inorganic N availability with respect to conventional tillage in a semi-arid vineyard was evaluated.
Abstract: Little attention has been given to the utilization of permanent cover crops in vineyard agroecosystems in semi-arid Mediterranean climatic conditions to increase soil organic carbon or its effects on N availability. We evaluated the effect of permanent cover crops with resident vegetation on labile organic matter fractions and inorganic N availability with respect to conventional tillage in a semi-arid vineyard. The field experiment was conducted on Typic Haploxerept soil, located in La Rioja area (Central River Ebro Valley). Soil samples were collected during June 2009, 5 years after covers crops were established. Soil organic carbon (SOC), water-soluble carbon (WSC), potentially mineralizable nitrogen (PMN), nitrate (N-NO3 −) and ammonium (N-NH4 +) were measured. At soil depths of 0–2.5 and 2.5–5 cm the cover crops increased SOC, WSC and PMN. So the results indicated a soil quality improvement. The cover crop treatment reduced soil N-NO3 − and increased the WSC to inorganic N ratio at 0–45 cm depth. PMN...
TL;DR: This review surveys the current advances in engineering abiotic stress-tolerant plants, particularly the genetic engineering of osmolyte genes (osmoprotectants) for imparting drought stress tolerance in plants.
Abstract: Abiotic stress is one of the primary causes of crop losses worldwide (Bray et al. 2000. Responses to abiotic stresses. In: Buchanana BB, Gruissem W, Jones RL, editors. Biochemistry and Molecular Biology of Plants. Rockville (MD): American Society of Plant Physiologists. p. 1158–1249). To cope with the detrimental effects of stress, plants have evolved many biochemical and molecular mechanisms. One of the well-documented stress responses in plants is accumulation of osmolytes during stress. Although their actual roles in plant-stress tolerance remain controversial, these molecules are thought to have positive effects on enzyme and membrane integrity, along with adaptive roles in mediating osmotic adjustment in plants grown under drought conditions. Recent studies have demonstrated that the manipulation of genes involved in the biosynthesis of these osmolytes have improved plant tolerance to drought and salinity in a number of crops. There is renewed hope of understanding the molecular basis of osmolyte acc...
TL;DR: In this paper, a four-layer ANN with three and four nodes in the hidden layers, performed the best in predicting the unsaturated hydraulic conductivity, K ψ [at six applied tensions (ψ) of 0-0.2 m] and sorptive number, α (at five ψ values of 0.03 − 0.2m) that correspond to 138 soil samples from two neighboring study areas located in the Agricultural College, Shiraz University, Islamic Republic of Iran.
Abstract: Direct measurement of unsaturated hydraulic parameters that are crucial inputs in any modeling of water flow or solute transport through the vadose zone is costly and time-consuming. Therefore, indirect methods like artificial neural networks (ANNs) can be used to estimate these parameters. Different ANNs conditions [two training algorithms (Trainlm and Traingd), two transfer functions (Tansig and Logsig), and different combinations of the input variables sand, silt, clay, bulk density (BD), soil organic matter (SOM) and initial (⊖i) and saturated (⊖s) volumetric water content] were used to predict the unsaturated hydraulic conductivity, K ψ [at six applied tensions (ψ) of 0–0.2 m] and sorptive number, α (at five ψ values of 0.03–0.2 m) that correspond to 138 soil samples from two neighboring study areas located in the Agricultural College, Shiraz University, Islamic Republic of Iran. A four-layer ANNs with three and four nodes in the hidden layers, performed the best in predicting K ψ and α. Traingd prod...
TL;DR: In this paper, the effects of phosphorus fertilizer application on performance of intercropped maize and soybean were investigated at the Ladoke Akintola University of Technology, Ogbomoso, Nigeria in 2007 and 2008.
Abstract: Field experiments were conducted at the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso, Nigeria in 2007 and 2008 to determine the effects of phosphorus fertilizer application on performance of intercropped maize and soybean. The experiments, arranged as a split plot in a randomized complete block design, replicated four times. A cropping system with sole maize, sole soybean and maize/soybean intercrop formed the main plot treatments while P rates with 0, 15 and 30 kg P2O5 ha−1 were the subplot treatments. For both years, neither P fertilizer application nor cropping systems had a significant effect on maize grain yield. However, soybean grain yield was significantly higher (92.3% in 2007 and 44.5% in 2008) under sole cropping than under maize/soybean intercropping. On average, N fixed by soybean increased with the increase in P rate (from 51.8% without P to 60.5% with 30 P), but there was no significant difference in N fixed by sole soybean and soybean/maize intercrop. Howe...
TL;DR: In this article, the results revealed that the ranges of influence for pH, EC,, K, P, Zn, Fe, B and Co were 65, 55, 78, 79, 75, 60, 50, 65, 70 and 30.
Abstract: Determination of the chemical characteristics of soil for balanced fertilization on large scales is an important factor in achieving a precision agriculture. Laboratory analyses of soil properties are usually expensive and time consuming. Surmounting these problems is possible using geostatistics. Therefore, this research aims at selecting a proper interpolation method using 213 soil samples for alfalfa farmland in Hamadan Province, Iran. Various factors such as pH, EC, , , K, P, Fe, Zn, B and Co were measured. Ordinary kriging and co-kriging were assessed to derive maps of soil physico-chemical properties, using mean absolute error (MAE), mean bias error (MBE), root mean squared error (RMSE) and average kriging standard error (AKSE) as statistical criteria. Variography analysis indicated that the ranges of influence for pH, EC, , , K, P, Zn, Fe, B and Co were 65, 55, 78, 79, 75, 60, 50, 65, 70 and 30 km, respectively, and the measuring error varied between 0.366 and 0.843. The results revealed that, base...
TL;DR: In this article, the effects of vermicomposting on wheat yield and nutrient content in soil and plant were studied in a greenhouse experiment in terms of the effects on wheat (Triticum aestium).
Abstract: Vermicomposting of organic waste can play an important role in integrated waste management strategies. Ability of the earthworm Eisenia foetida to transform anaerobically digested sewage sludge (SS) amended with hazelnut husk (HH) and cow manure (CM) in different proportions (0% SS + 50% HH + 50% CM; 10% SS + 45% HH + 45% CM; 20% SS + 40% HH + 40% CM; 30% SS + 35% HH + 35% CM; 40 SS% + 30% HH + 30% CM; 50% SS + 25% HH + 25% CM) was studied in a greenhouse experiment in terms of the effects of vermicompost on wheat (Triticum aestium) yield and nutrient content in soil and plant. All vermicomposted and non- vermicomposted mixtures exhibited positive effect on the yield and nutrient concentrations of wheat compared to the control pots. The vermicomposted organic waste mixtures showed comparatively better effect on plant production than the non- vermicomposted organic waste mixtures. Vermicomposted 50% SS + 25% HH + 25% CM mixtures showed the highest positive effect on yield compared to the other treatments.
TL;DR: This new approach may help to investigate the tolerance of A. littoralis to Cd stress for use in phytoremediation, when grown in soil contaminated with cadmium.
Abstract: To our knowledge there has been no research on Aeluropus littoralis as a halophyte plant, when grown in soil contaminated with cadmium (Cd). Hence, the ability of A. littoralis to take up Cd and some nutrients was investigated in a pot experiment. Five levels of soil Cd concentration were tested (15, 30, 60, 120 and 240 mg Cd kg−1 soil). Plants were harvested at three different times and analyzed for Cd, N, P, K, Mg, Mn, Cu, Fe and Zn concentrations. Plant biomass decreased as a result of excess Cd. Cadmium concentration in plant shoots increased with increasing Cd supply, significantly affecting the plant nutrient content. An excess Cd supply increased macronutrient and decreased micronutrient concentrations in the plant. Although, the research process will become more complicated, this new approach may help to investigate the tolerance of A. littoralis to Cd stress for use in phytoremediation.
TL;DR: Seed inoculation of mung bean with or without tricalcium phosphate was performed to study the effect of single and dual bacterial inoculations in pot trials having sterilized sandy loam soil, and was found to enhance the growth and yield of plants.
Abstract: Available phosphorus is limiting in most cultivable soils in several parts of India, including Rajasthan. Four phosphate-solubilizing bacterial strains viz. Pseudomonas fluorescens BAM-4, Burkholderia cepacia BAM-6, B. cepacia BAM-12 and Aeromonas vaga BAM-77 were isolated from the rhizosphere of pearl millet (Pennisetum glaucum, cv. Raj 171), mung bean (Phaseolus aureus, cv. RMG 492) and sesame (Sesamum indicum, cv. RT 46). To the best of our knowledge, this is the first report on phosphate solubilization by Aeromonas vaga. Seed inoculation of mung bean with or without tricalcium phosphate (TCP) was performed to study the effect of single and dual bacterial inoculations in pot trials having sterilized sandy loam soil, and was found to enhance the growth and yield of plants. The results were on a par with chemical fertilizer, single superphosphate (SSP) and commercial biofertilizers, PSB (Bacillus polymyxa) and MC (Pseudomonas striata), used as standard reference. Addition of TCP to soil gave better resul...
TL;DR: The need for scientific composting methods for effective utilization of organic waste is increasing day by day In this respect, a new process called the Novcom composting method is being increasingly adopted by the organic tea planters of Assam and Darjeeling (India) for large-scale composting study of the biodegradation process under this method and quality evaluation of the end product was carried out at Maud tea estate (Assam) during 2008-2009 and 2009-2010 as discussed by the authors.
Abstract: The need for scientific composting methods for effective utilization of organic waste is increasing day by day In this respect, a new process called the Novcom composting method is being increasingly adopted by the organic tea planters of Assam and Darjeeling (India) for large-scale composting Study of the biodegradation process under this method and quality evaluation of the end product was carried out at Maud tea estate (Assam) during 2008–2009 and 2009–2010 Generation of high temperatures (>65°C) within the compost heap during the biodegradation process provided an indication regarding the destruction of pathogens and weed seeds in the composted material Samples collected on day 0, 7, 14, 21 and 30 of composting, were analyzed for physicochemical properties, nutrient status, microbial population, stability and phytotoxicity parameters The most significant finding was the high microbial population (in the order of 1016 cfu g−1) in the final product, which was generated naturally during biodegradati
TL;DR: In general, mycorrhizal inoculation enhanced the ability of wheat to cope with saline conditions and using AM inoculants can help plants to thrive in degraded arid/semi-arid areas.
Abstract: Two pot experiments were conducted in the greenhouse of the National Research Center, Egypt during 2003/2004 and 2004/2005 to investigate the efficacy of arbuscular mycorrhizae (AM) on root colonization, growth and productivity in two wheat cultivars, Sakha 8 and Giza 167, under salt stress. The extent of the AM effect on wheat development varied with plant cultivar and salinity level. Maximum root colonization and spore production were observed with the Sakha 8 cultivar, which resulted in greater plant growth and productivity at all salinity levels. AM and plant development were adversely affected by increasing salinity. However, the presence of mycorrhizal fungi protected wheat against the detrimental effect of salinity, and stimulated growth, productivity, total crude protein concentration and nitrate reductase activity. The average enhancement in grain yield due to AM inoculation was 76 and 68% at 0.15 mS cm−1, 93 and 84% at 3.13 mS cm−1, 130 and 115% at 6.25 mS cm−1, and 154 and 120% at 9.38 mS cm−1 ...
TL;DR: Overall, Sesbania aculeata green manuring and 2.0% ZEU (ZnSO4 · H2O) are excellent sources of N and Zn for improved productivity of Basmati rice.
Abstract: Field experiments were conducted to study the effects of summer green-manuring crops and zinc (Zn) fertilization on the productivity and economics of Basmati rice. Sesbania aculeata summer green-manuring crop residue incorporation (SGMI) gave highest values of all the growth and yield attributes, grain and straw yield, viz. 3.58, 3.69 t ha−1 and 16.14, 16.25 t ha−1 of Basmati rice in 2008 and 2009. Among the Zn fertilization treatments, application of 2.0% Zn-enriched urea (ZEU) as ZnSO4 · H2O significantly influenced yield attributes and yield of Basmati rice during both years, and the increase in grain yield was 38.5 and 40.0% over absolute control (no N and no Zn) and 11.9 and 13.6% over control (only N) in both years of study. However, 2.0% ZEU (ZnO) was very close in terms of yield attributes and grain, straw yields of Basmati rice. As regards to the economics of Basmati rice, SGMI and 2.0% ZEU (ZnSO4 · H2O) Zn fertilization treatments gave the highest gross (SGMI, 85,985 and 91,582 INR ha−1; 2.0% ZE...
TL;DR: During the current investigation, 51 bacterial isolates/mutants of Azotobacter chroococcum, Azospirillum spp.
Abstract: During the current investigation, 51 bacterial isolates/mutants of Azotobacter chroococcum, Azospirillum spp. and Gluconacetobacter diazotrophicus were tested for antifungal activity against three fungal pathogens, namely Rhizoctonia solani cotton, Rhizoctonia solani rice and Fusarium oxysporum tomato using a dual-culture technique under laboratory conditions. Ten isolates/mutants were found to be inhibitory against R. solani cotton, six against R. solani rice and twelve against F. oxysporum tomato. Nearly 50% of the isolates/mutants were siderophore positive. The antimicrobial substance was found to be extracellular and proteinaceous in nature, but in some strains it was found to be associated with other complex material also. Almost all the positive isolates/mutants showed production of antibiotic and antifungal compounds. On the basis of this study, in vitro results under laboratory conditions were reproduced in pot experiments in the greenhouse and chosen isolates/mutants of A. chroococcum were found ...
TL;DR: In this article, the authors used a tension disc infiltrometer to measure physico-chemical and hydraulic soil attributes, including unsaturated hydraulic conductivity (K ψ) and sorptivity coefficient (S) at six applied tensions of 0 to 0.2 m.
Abstract: Due to the existence of gravelly soils and the lack of sufficient research on such soils, this study was carried out on a gravelly calcareous soil. Selected physico–chemical and hydraulic soil attributes were determined at 69 points on a nested-sampling design. Hydraulic characteristics including unsaturated hydraulic conductivity (K ψ) and sorptivity coefficient (S) at six applied tensions of 0 to 0.2 m, and sorptive number (α) and macroscopic capillary length (λ) at five applied tensions of 0.03 to 0.2 m were determined using a tension disc infiltrometer. Hydraulic and chemical soil attributes were the highest and the lowest variants, respectively. The maximum and minimum values for the coefficient of variation (CV) in all the measured physico-chemical and hydraulic soil attributes were obtained for α0.2 and soil pH, respectively. Minimum, maximum, mean and variance values of K ψ, S and α decreased as applied tension increased. Although the pattern was reversed for λ. The majority of soil attributes sho...
TL;DR: In this paper, the diffusion coefficients of CO2 at 0-10 cm layers in undisturbed and tilled soil conditions were estimated using the Penman (Penman HL) and Millington-Quirk (Millington RJ, Quirk JP) models.
Abstract: Diffusion coefficients (D) of CO2 at 0–10 cm layers in undisturbed and tilled soil conditions were estimated using the Penman (Penman HL. 1940. Gas and vapor movement in soil, 1. The diffusion of vapours through porous solids. J Agric Sci. 30:437–463), Millington–Quirk (Millington RJ, Quirk JP. 1960. Transport in porous media. In: Van Baren FA, editor. Transactions of the 7th International Congress of Soil Science. Vol. 1. Amsterdam: Elsevier. p. 97–106), Ridgwell et al. (Ridgwell AJ, Marshall SJ, Gregson K. 1999. Consumption of atmospheric methane by soils: A process-based model. Global Biogeochem Cy. 13:59–70), Troeh et al. (Troeh FR, Jabro JD, Kirkham D. 1982. Gaseous diffusion equations for porous materials. Geoderma. 27:239–258) and Moldrup et al. (Moldrup P, Kruse CW, Rolston DE, Yamaguchi T. 1996. Modeling diffusion and reaction in soils: III. Predicting gas diffusivity from the Campbell soil–water retention model. Soil Sci. 161:366–375) models. Soil bulk density and volumetric soil water content (...
TL;DR: In this paper, a hillside field of 4 × 4 ha was selected as the study site and 111 soil samples were taken from the topsoil (0 − 20 cm), on an ∼20m grid.
Abstract: Currently, efficient and cost-efficient methods are needed to manage fields in order to maximize economic return, minimize environmental impact, and improve soil and crop site-specific management. Management zones (MZs) of uniform production potential may offer a solution to the problems associated with grid soil sampling while still effectively describing variability in soil properties. In this study, a hillside field of 4 ha was selected as the study site and 111 soil samples were taken from the topsoil (0–20 cm), on an ∼20-m grid. Soil samples were analyzed for pH, organic matter, active soil organic matter, total nitrogen, alkalytic nitrogen, available phosphorous, available potassium and cation-exchange capacity. Their spatial variability was analyzed and spatial distribution maps were constructed using geostatistical techniques. Principal component analysis (PCA) and fuzzy c-means clustering algorithm were then performed to delineate MZs, and eigenvalues were used to select the principal components ...
TL;DR: Field experiments showed that inoculation of these fungi along with RP fertilization significantly increased yield and nutrient uptake of wheat and maize plants compared with control soil, suggesting that the fertilizer value of RP can be increased, especially in alkaline soils, by inoculating P-solubilizing fungi.
Abstract: Aspergillus tubingensis and A. niger were isolated from the landfills of rock phosphate mines and tested for their efficacy to solubilize rock phosphate (RP), and improve plant growth and phosphate (P) uptake by plants grown in soil amended with RP. The results showed that they effectively solubilized RP in Pikovskaya's (PKV) liquid medium and released significantly higher amounts of P into the medium. A. tubingensis solubilized and released 380.8 μg P mL−1, A. niger showed better efficiency and produced 403.8 μg P mL−1. Field experiments with two consecutive crops in alkaline agricultural soil showed that inoculation of these fungi along with RP fertilization significantly increased yield and nutrient uptake of wheat and maize plants compared with control soil. P uptake by wheat and maize plants and the available P increased significantly in the RP-amended soil inoculated with fungi compared with control. These results suggest that the fertilizer value of RP can be increased, especially in alkaline soils...