Estimation of turnover and equilibrium of soil organic matter using a mathematical approach

The methods based on N uptake of aerial-plants, soil organic matter （SOM） dynamics, Jenny＇s equation, and actual measurement of long-term field experiments in Jiaxing, Quzhou, Huangyan and Hangzhou of Zhejiang Province, China were used to determine the organic mineralization rate being helpful in estimating the organic requirement for SOM equilibrium. The results showed that the estimated mineralization ratios of SOM for Jiaxing and Quzhou were, respectively, 0.0404 and 0.0508 based on N uptake of aerial-plants in non-fertilized plots; 0.0405 and 0.012 using SOM dynamics in non-fertilized plots; and 0.0413 and 0.0513 using the actual investigated data and Jenny＇s equation. With Jenny＇s equation, soil organic C balance in manure ＋ N-P-K plots was estimated at nearly 28.8 g kg^-1 for Jiaxing and 32.4 g kg^-1 for Quzhou with predicted SOM linearly related to the actual investigated values （r^2 = 0.9640 for Jiaxing and 0.8541 for Quzhou）. To maintain the SOM balance in the non-fertilized plots the recommended rate of organic materials was 3 000-6 600 kg ha^-1, and the relevant rates of farm yard manure （FYM） in the manure and N-P-K plots were estimated at 3 375 （dry） and 17670 kg ha^-1 （wet） for Jiaxing, 1845 （dry） and 6090 kg ha^-1 （wet） for Quzhou.     

Interaction between β-casein and whey proteins as a function of pH and salt concentration

The effectiveness of β-casein as a chaperone in the aggregation of whey proteins was investigated. β-Casein altered heat-induced aggregation as shown by a reduction in turbidity of β-lactoglobulin, α-lactalbumin, and bovine serum albumin (BSA) solutions. The pH of the mixtures greatly affected how much β-casein reduced the turbidity of the solutions; the maximum reductions in turbidity were observed at pH 6.0. Reducing the pH decreased the effectiveness of β-casein as a chaperone. An increase in ionic strength by the addition of NaCl or CaCl(2) also decreased the effectiveness of the chaperone. The addition of CaCl(2) had a larger effect than the addition of NaCl. The chaperone effect was seen at temperatures up to 145 °C. Differential scanning calorimetry (DSC) showed that β-casein did not alter the denaturation temperature of β-lactoglobulin. The kinetics curves for loss of native protein and turbidity development showed that β-casein did not function by slowing the aggregation process. It was concluded that β-casein competes with whey protein in the aggregate process and the aggregates formed in the presence of β-casein are smaller in size than those formed during whey protein self-aggregation. The formation of smaller aggregates gives rise to less turbid, more soluble protein solutions.     

Comparison of the hydrolysis of bovine κ-casein by camel and bovine chymosin: a kinetic and specificity study

Bovine chymosin constitutes a traditional ingredient for enzymatic milk coagulation in cheese making, providing a strong clotting capacity and low general proteolytic activity. Recently, these properties were surpassed by camel chymosin, but the mechanistic difference behind their action is not yet clear. We used capillary electrophoresis and reversed-phase liquid chromatography-mass spectrometry to compare the first site of hydrolysis of camel and bovine chymosin on bovine κ-casein (CN) and to determine the kinetic parameters of this reaction (pH 6.5; 32 °C). The enzymes showed identical specificities, cleaving the Phe105-Met106 bond of κ-CN to produce para-κ-CN and caseinomacropeptide. Initial formation rates of both products validated Michaelis-Menten modeling of the kinetic properties of both enzymes. Camel chymosin bound κ-CN with ～30% lower affinity (K(M)) and exhibited a 60% higher turnover rate (k(cat)), resulting in ～15% higher catalytic efficiency (k(cat)/K(M)) as compared to bovine chymosin. A local, less dense negatively charged cluster on the surface of camel chymosin may weaken electrostatic binding to the His-Pro cluster of κ-CN to simultaneously impart reduced substrate affinity and accelerated enzyme-substrate dissociation as compared to bovine chymosin.     

Distribution and Transport of Residual Lead and Copper Along Soil Pro?les in a Mining Region of North China

Residual heavy metals are commonly considered to be immobile in soils,leading to an underestimation of their environmental risk.This study investigated the distribution and transport of residual heavy metals along soil pro?les,using the Xiaoqinling gold mining region in North China as a case study.Soil samples were collected at three depths from three locations near the tailing heap.The speciation of copper(Cu) and lead(Pb)(exchangeable,carbonate-bound,Fe-Mn oxide-bound,organic matter-bound,and residual fractions) was determined using a sequential extraction procedure.The residual fraction's morphology was observed using scanning electron microscopy(SEM).Results showed that metal fraction distributions along the soil pro?les were in?uenced by each fraction's mobility.Residual fraction with high chemical stability can not be transformed from or into other fractions.This led to the conclusion that the high concentration of residual metals in soils mainly resulted from residual fraction transport.The SEM analysis showed that ?ne particles(submicrons) were mainly attached to large particles and were likely released and transported by water?ow.The more sorptive fractions(non-residual fractions) were mainly retained in the top soil,and the more mobile fractions(residual fraction) were mainly leached to the deep soil.Cu and Pb concentrations in the residual fraction decreased slightly and those in the non-residual fractions decreased signi?cantly with soil depth.These suggest a relatively higher residual metal mobility along the soil pro?les.Therefore,residual metals can be transported in soils and their environmental risk can not be ignored in assessing soil contamination.     

Effects of a tropical cyclone on littoral and sub-littoral biotic communities and on a population of Dugongs (Dugong dugon (Müller))

The extensive damage to littoral and sub-littoral biotic communities caused by cyclone ‘Althea’, which crossed the tropical coast of Queensland on 24 December, 1971, are described. The effects of high wind speeds (mean 129·7 km/h), turbulent seas, storm surges, and heavy rainfall on mangrove, sea grass, algal, and coral reef communities are discussed. Mangroves withstood the immediate effects of the cyclone and protected coastal areas. However, long-term effects on mangroves are apparent. Severe wave action, shifting sand, and low salinities caused extensive damage to sea grass, algal, and coral reef communities. The effects of the cyclone on a Dugong population are described. The catches of Dugongs in shark nets set off Townsville increased from an average of 12·7 per year before the cyclone to 41 in 1972 (the year following the cyclone). This increase is attributed to increased movements in search of food, following extensive damage to sea grass beds. Associated with increased movements, there occurred a change in diet whereby large amounts of brown algae were eaten in addition to sea grasses. Sex and size (age) distributions of captured Dugongs are given and their possible significance discussed.     

Relationship between signaling and metabolic pathways of grapevines under temperature and light stresses—a review

Depending on plant genotype–environment interactions, cell signal transduction, and thereby gene expression, disruptive or promotive effects on grapevine physiology, metabolism, and, consequently, fruit quality and yield may occur. This review article aims to evaluate the effects of temperature and light stress on grapevine signaling and metabolic pathways to provide insights into breeding/engineering strategies for designing grapevines with improved quality, yield and tolerance. The modifications of signaling and metabolic pathways are discussed to assist geneticists with designing tolerant grape cultivars with high capacity of producing bioactive compounds and, thereby health-promoting effects in grapevines and humans.     

Effect of Salinity and Some Chemical Properties of the Under‐ and Intercanopy Soils on Range Plants in a Dry Region of Southern Iran

Abstract

The present study was conducted in a dry region in southern Iran to evaluate the effects of different Atriplex species on the salinity, soluble ions, and some of the other chemical properties of under‐ and intercanopy soils. The research region was divided into five separate sites with vegetation cover of the range plants Atriplex lentiformis, A. nummularia, and A. halimus (all newly introduced species) and A. leucoclada and Salsola rigida (both native species). Four 1‐kg soil samples (from under‐ and interspaces of the canopy of tested plants, each in two depths of 0–10 and 10–40 cm, were taken from each of the plant sites and analyzed for different determinations. The study was conducted as a factorial experiment in a complete random design with six replicates.

Regardless of distance and depth, different plant species resulted in different salinity (based on the EC values of saturation paste) and soluble cation contents in the tested soils. The results showed that the increase in EC values were associated with decreases in pH values of the tested soils.

The SAR values followed exactly the same pattern as EC values and Na⁺ concentrations. In the case of soluble anions, the Cl^? contents followed exactly the same pattern as the EC values of the tested soils, which indicates that the salts are predominantly chlorides of various cations (especially Na⁺). The OM and total nitrogen (N) contents of the undercanopy were greater than those of the interspace and those of the surface layer were greater than those of the sublayer. Moreover, although the phosphorus (P) and potassium (K) contents of undercanopy and interspace were not significantly different from each other, the P and K contents of the surface layer were greater than those of the subsurface layer. As seen from the results, except for the effect of depth of Mn contents and the interactive effect of distance and depth on Fe contents, neither the single effects (other than plant species) nor the interactive effects were significant on microminerals of the tested soils.

Moreover, copper (Cu) was particularly antagonistic toward iron (Fe), manganese (Mn), and zinc (Zn).     

Nitrate removal from ground water — use of a nitrate selective resin and a low concentrated regenerant

A new, strong base, macro-porous anion exchange resin, Amberlite IRA 996, appeared to be more nitrate selective than sulfate selective in treating high nitrate concentrations (18 mg NO _inf3 ^sup? -N L^?1) in potable water. When regeneration is carried out in a closed circuit in which a biological denitrification reactor is incorporated to remove nitrate from the regenerant, regeneration salt requirement and brine production can be minimized. In this combination of ion exchange and biological denitrification, regeneration with 30 g NaHCO₃ L^?1) is possible in 6 hr at a flow rate of 11 BV hr^?1. Accumulation of sulfate in the closed regeneration circuit does not affect the nitrate capacity of the resin.     

Total oxidant scavenging capacity of Euterpe oleracea Mart. (açaí) seeds and identification of their polyphenolic compounds

The antioxidant capacity of methanol and ethanol seed extracts from Euterpe oleracea Mart. (a?aí) against the reactive oxygen species (ROS) peroxyl radicals, peroxynitrite, and hydroxyl radicals was studied with the total oxidant scavenging capacity (TOSC) assay in a modified and automated version. Cold methanol digestion was the most efficient extraction method with respect to the antioxidant capacity. The extracts exhibit good antioxidant capacity against peroxyl radicals, similar to the capacity of the pulp. The antioxidant capacity against peroxynitrite and hydroxyl radicals is even higher. The main antioxidants identified by HPLC-MS and HPLC-CEAD are five different procyanidins (di- through pentamers); furthermore, protocatechuic acid and epicatechin were identified as minor compounds. Determination of TOSC values of HPLC seed extract fractions indicates that the procyanidins contribute substantially to the overall antioxidant capacity. In addition, however, other compounds that have not yet been identified are responsible for a large part of the observed antioxidant capacity.     

Decomposition of cattle manure and colonization by macroinvertebrates in sediment of a wetland of the Middle Paraná River

Purpose

The study was carried out in a wetland of the Middle Paraná River system, Argentina, in order to evaluate the processes associated with the decomposition of manure, which includes changes in chemical composition, nutrient release of manure, and colonization of invertebrates. We also compared the invertebrate assemblage that colonized manure with that present in the benthos of the wetland.

Materials and methods

Nylon bags were filled with fresh cattle manure and anchored to the littoral zone of the wetland. Six bags were collected after 1, 2, 6, 14, 21, 28, 33, 55, and 79 days: three for invertebrate determination and the other three bags for determination of dry mass and chemical analyses. The nutrient content, cellulose, lignin, and total phenolic compounds of manure were determined. In addition, the leachate of manure was collected for nutrient analyses. Samples of the wetland benthic sediment were collected for benthic invertebrate determination and particle size analyses. Spearman rank correlation was used to evaluate the relationship between chemical compounds of manure and breakdown rate. Principal component analysis was used to explore invertebrate assemblage composition of manure and sediment during the experiment.

Results and discussion

Limnodrilus, Dero, and Chironomus were dominant in the manure. Gatherer-collector was the dominant group in the manure, comprising almost 95 % of the total density of invertebrates. Breakdown rate was significantly related with nutrients, cellulose and total phenolics of manure. An ordination plot showed changes in invertebrate assemblages of manure and sediment samples over time.

Conclusions

This study provides new insight on the importance of manure as a substrate for macroinvertebrate colonization. Cattle manure needs to be considered as a potential source of nutrients for aquatic systems and a substrate for invertebrate assemblages.

     

Transport of Strontium Through a Ca-bentonite (Almer??a, Spain) and Comparison with MX-80 Na-bentonite: Experimental and Modelling

In this work, the sorption of strontium on a Ca-bentonite (CGA) from Almer??a (Spain) in column experiments was studied, and the results obtained were compared with the sorption onto the Na-bentonite (MX-80). The code CTXFIT (two site non-equilibrium sorption model) was used in order to fit the experimental data and to determine sorption and transport parameters. The effect of inlet Sr(II) initial concentration and the ionic strength were evaluated. The results obtained showed that the sorption capacities as well as the transport and sorption parameters of both bentonites were affected by the initial metal concentration. In experiments with higher inlet concentrations, columns were saturated faster, leading to shorter breakthrough and exhaustion times. On the other hand, a decrease of sorption and transport parameters was observed at higher ionic strengths, which would confirm ion exchange as the main mechanism of Sr(II) sorption onto both bentonites. The sorption parameters (sorption capacity and retardation factor) obtained indicated that the Ca-bentonite from Almer??a (Spain) presented better sorption performance than the Na-bentonite, which was related to the physical properties of the Ca-bentonite.     

The effect of a mixture of two plant growth-promoting bacteria from Argentina on the yield of potato,and occurrence of primary potato diseases and pest – short communication

In 2017, we conducted a field experiment to test the influence of a mixture of two plant growth-promoting bacteria (Pseudomonas fluorescens and Azospirillum brasilense) on the yield of three potato varieties. In addition, the influence of the mixture on potato susceptibility to infection by the pseudofungus Phytophthora infestans and fungus Alternaria solani and to attacks by the Colorado potato beetle (Leptinotarsa decemlineata) was investigated. It was the first experiment of its kind in Europe. In the unusually hot and dry year, a positive influence on the yield (17%–31%) was found in all three varieties when the tubers were soaked in the bacterial mixture prior to sowing. We observed no significant differences in potato resilience/susceptibility to harmful organisms among the different treatments (soaked tubers, sprayed tubers, untreated tubers); however, there were significant differences in the productivity between the tuber varieties. The results of our research indicate the bacterial mixture used in this study has a high potential to support satisfactory potato yields under dry conditions and under low levels of infection by foliar fungal diseases and attacks by foliar insects.     

Effect of Mussel��s Gender and Size on a Stress Response Biomarker

In mussels, stress signals such as heat, osmotic shock and hypoxia lead to the activation of the phosphorylated p38 mitogen activated protein kinase (pp38-MAPK). This stress activated protein has been efficiently used as a biomarker to several natural and anthropogenic stresses. However, what has not been tested is whether differences in gender or size can affect the response of this biomarker. The present study tested whether there was variation in the expression of pp38-MAPK in mussels Perna perna of different gender and size classes when exposed to natural stress conditions, such as air exposure. The results show that gender does not affect the expression of pp38-MAPK. However, size does have an effect, where mussels smaller than 6.5 cm displayed significantly (p?<?0.05) lower levels of pp38-MAPK when compared to those larger than 7 cm. Mussels are one of the most used bioindicator species and the use of biomarkers to determine the health status of an ecosystem has been greatly increasing over the years. The present study highlights the importance of using mussels of similar size classes when performing experiments using stress-related biomarkers.     

PH—Postharvest Technology: Monitoring and Performance of a Commercial Grain Dryer

This paper presents detailed in situ experimental results for the performance of a commercial batch grain dryer under real operating conditions while drying barley. The distribution of key drying parameters of air temperature, relative humidity, airflow, grain moisture content, drying time and energy use are measured. For the two trials conducted, the overall cycle-averaged process thermal efficiency is 48·4 and 41·5%, respectively. This is achieved when the average initial moisture contents of the grain are, respectively, 15·7 and 17·2% and the highest plenum temperatures 41·4 and 34·0°C. During drying, unlike the stack-on temperatures, the exhaust air temperatures after the grain stack are fairly stable and only mildly affected by the variation of ambient conditions. After the initial heating period, the air enthalpy remains practically constant through the grain stack section. Close to the dryer centre, because of the presence of the auger, the air velocity is considerably lower than other parts of the dryer. The drying appears to be dominated by a drying front advancing through the grain stack. The reduction of grain moisture content is much faster during the last few hours of the drying process. The experiments highlight the importance of accurate measurement and representation of product moisture contents and airflow.     

Patterns and correlates of human–elephant conflict around a south Indian reserve

Success stories in Indian conservation also carry opportunity costs in the form of human–wildlife conflicts, especially to people living in close proximity with wildlife. In India, human–wildlife conflict is a serious challenge to wildlife conservation, which needs a much-improved scientific and social understanding. In this study, I assess the patterns and correlates of human–elephant conflicts around Nagarahole National Park, southern India. I hypothesised that human and livestock demographic variables, and factors such as cropping patterns, availability of irrigated land around the national park, and protected area frontage to be the underlying correlates of conflict. Using applications and documents filed with the wildlife department by affected farmers during the period 2006–2009, I analysed crops affected, compensation payments made by the Government, spatio-temporal patterns of conflict and identified the key correlates of human–elephant conflict. 98.8% of the conflict incidences occurred in villages that lie within 6 km from the national park boundary. Of the 26 crop types affected by elephants, finger millet, maize, cotton, paddy and sugarcane formed 86.34% of the total crop losses. Conflict frequencies were highest during August–November, a period when there was a decrease in rainfall and important crops such as finger millet, maize and paddy were ripening. Multiple linear regression results suggest that villages with higher protected area frontage and unirrigated land were key variables underlying conflict frequency. However, results from this study suggests that there are other probable factors such as elephant behaviour, movement patterns and/or maintenance of physical barriers which could be more important determinants of conflict.     

Foliar fertilization–induced injury and recovery of a creeping bentgrass putting green

Two independent trials were conducted on a creeping bentgrass (Agrostis stolonifera L.) putting green (PG) to evaluate early-response of canopy quality, growth, and nutrient use to rate and/or type of foliarly-applied nitrogen (N) fertilizer. Treatments were prepared using soluble ‘Amine’ or ‘Salt’ 15N–0 phosphorus (P)–5.8potassium (K) fertilizer and applied N at 0, 24.5, 37, or 49 kg ha^?1. Clipping yields were weighed and digested for N content. Normalized differential vegetative (NDVI) and dark green color (DGCI) indices were determined by canopy reflectance. Relative to the Salt fertilizer, the Amine supported greater mean growth and N offtake rates and higher mean NDVI and DGCI. Two and five days after treatment (DAT), salt-fertilizer treated plots showed lesser canopy quality relative to Amine. These differences increased with N rate, likely due to the greater solute concentration of the Salt fertilizer. Eight to 21 DAT, fewer differences were observed by fertilizer type or rate.     

From soil to rice – a typical study of transfer and bioaccumulation of heavy metals in China

For the purpose of studying the contamination, bioaccumulation and transfer of heavy metals and understanding the effects of soil properties on these, the work was carried out on a regional scale. A total of 30 sets of soil and pairing rice tissues samples (root, straw and grain) were collected in Xiangzhou of Guangxi, China; soil properties and Cd, Cu, Pb and Zn of different rice tissues were analyzed. The mobility and bioaccumulation of Cd, Cu, Pb and Zn were assessed by transfer coefficients and bioaccumulation factors of them. The results indicated that the excess proportions of Cd and Pb were 50%, 3.33% and 30%, 6.67% in soil and rice grain, respectively, according to Chinese maximum permitted concentrations of heavy metals. Cd and Zn showed stronger bioaccumulation and mobility capability; the bioaccumulation and transfer of Cu were slightly lower than Cd and Zn; Pb had the weakest mobility. The bioaccumulation and mobility of heavy metals from soil to rice were restrained by soil pH, CaO, SOC, Fe oxides and Mn.