Dynamics of organic carbon and nitrogen in deep soil profile and crop yields under long-term fertilization in wheat-maize cropping system

Soil organic carbon(SOC) and nitrogen(N) are two of the most important indicators for agricultural productivity. The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile(up to 100 cm) and their relationships with crop productivity under the influence of long-term(since 1990) fertilization in the wheat-maize cropping system. Treatments included CK(control), NP(inorganic N and phosphorus(P) fertilizers), NPK(inorganic N, P and potassium fertilizers),...     

Straw and biochar effects on soil properties and tomato seedling growth under different moisture levels

ABSTRACT

A greenhouse experiment was conducted to evaluate the effects of wheat straw and its biochar on tomato seedling growth and soil physicochemical properties under different moisture levels. Treatments included control (no amendments, CK), three biochar amendments (B1: 1%, B2: 3% and B3: 6% w/w) and three straw amendments (S1: 1%, S2: 3% and S3: 6% w/w), under two moisture levels (M1: 40% water holding capacity (WHC) and M2: 70% WHC). The straw and biochar had contrasting effects on soil physiochemical properties and physiology of tomato seedlings. The B1 treatment significantly increased the soil urease activity (15%) and decreased the activity of dehydrogenase and β glucosidase enzymes (67% and 56%), as compared to the S1 treatment, especially for the high moisture condition. Biochar significantly improved shoot and root dry weights, biomass and altered chlorophyll contents. Plant antioxidants, superoxide dismutase (SOD), Peroxidase (POD) activities and malondialdehyde (MDA) were significantly decreased in biochar treatments, however, an increasing trend was observed for straw treatments. The current findings suggest that application of high amount of biochar (6%) or low amount of straw (1%) would be a reasonable management practice in semi-arid regions to improve soil physiochemical properties and the physiology of tomato seedlings.     

Impacts of Irrigation with Water Containing Heavy Metals on Soil and Groundwater – A Simulation Study

This research work intended to study the impacts of irrigation water containing various levels of copper, lead, and zinc on adsorption capacity of soil packed in 4′′ plastic columns and obtained from two locations around the city of Nablus: Salem (A) and Deir Sharaf (B). Results of simulation experiments showed an increase in the copper, lead, and zinc concentrations in soil and in leachate with increasing the amount of metal in irrigation water. Copper, lead, and zinc concentrations increased also with soil depth and duration of application. The results also indicate that the self purification of both soils was highly affected by physical factors, i.e. the intermittent application of irrigation water to the soils in the columns caused soil wetting and drying cycles whichresulted in the formation of cracks in shrinked soils specially in the top half of the columns. Crack formation is common in such clay soils due to the climatic conditions (Mediterranean type: dry summers and wet winters) and type of clay minerals in the soil. Thus, short circuiting of water through cracks results in moving contaminants fast and deep in the soil profile.     

Long-Term Application of Chemical and Organic Fertilizers over 35 Years Differentially Affects Interannual Variation in Soil Inorganic Phosphorus Fractions in Acidic Paddy Soil

Eurasian Soil Science - Phosphorus plays an important role in double rice cropping systems grown on acidic paddy soil. To improve our knowledge and increase crop utilization of applied phosphorus...     

Influence of methionine and dithioerythritol on sperm motility, lipid peroxidation and antioxidant capacities during liquid storage of ram semen

The aim of this study was to investigate the effects of methionine and dithioerythritol, added to the Tris extender, on ram sperm motility and LPO (lipid peroxidation) and antioxidant capacities during liquid storage up to 72 h at 5 °C. Ejaculates collected from five Merino rams, were evaluated and pooled at 37 °C. This study included two experiments. In experiment 1, each pooled ejaculate was divided into four equal aliquots and diluted (37 °C) with the base extender, containing 0 (control), 1, 2 and 4 mM methionine, at a final concentration of approximately 4 × 10⁸ sperms/ml (single step dilution), in a 15-ml plastic centrifuge tube. In experiment 2, dithioerythritol, at concentrations of 0 (control), 0.5, 1 and 2 mM, was used as an additive in the extender, and the procedure explained above was applied for the division of aliquots and the dilution of semen. Diluted semen samples were kept in glass tubes and cooled from 37 to 5 °C in a cold cabinet, and maintained at 5 °C. Sperm motility and LPO and total glutathione (GSH) and glutathione peroxidase (GPx) capacities were determined at 5 °C for periods of 0, 24, 48 and 72 h of liquid storage.The extender supplemented with 1 mM methionine led to higher motility percentages (77.0 ± 1.2%), in comparison to the control group (66.0 ± 4.9%), during 72 h of liquid storage (P < 0.05). As regards dithioerythritol, it did not statistically improve the motility rates for any of the storage times at 5 °C. In biochemical assays, differences in LPO levels between the groups with antioxidants and the control groups were not statistically significant. Compared to the control group, no significant difference was observed in GSH and GPx activities following the addition of methionine, during 72 h of storage. Total GSH and GPx activities did not increase significantly upon supplementation with 0.5 and 1 mM of dithioerythritol, compared to the control group, at any of the time points (P > 0.05). Dithioerythritol at 2 mM led (P < 0.01) to elevating GSH activity, compared to the control group, during 72 h of liquid storage. GPx activity was approximately 10 times higher for 2 mM of dithioerythritol (P < 0.001), compared to that of the control group at all time points.The question regarding the sustainability of sperm survival, LPO and antioxidant capacities following liquid storage of semen remains unanswered. Further studies are required for a better understanding of the biochemical changes and to obtain more information on the determination of lipid peroxidation and antioxidant capacities during cooled storage of ram semen.     

Antioxidant effects of supplementation of 3,4-dihydroxyphenyl glycol on sperm parameters and oxidative markers following cryopreservation in canine semen

Supplementing the extender with antioxidants with low molecular weight can enhance the quality of the post-thaw sperm during the freezing process. This study was aimed at determining the impacts of 3,4-dihydroxyphenyl glycol (DHPG) on the spermatozoa of the canine undergoing freeze-thawing process. In this study, 24 ejaculates were obtained from three mixed-breed dogs and were diluted in a Tris-based extender. The diluted semen was divided into aliquots for supplementation of 10, 30, 50 and 70 µg/ml of DHPG, control (without antioxidant) and control sham (DMSO). After being extended, the semen was equilibrated at a temperature of 4°C and then transferred to the straws and kept 4 cm above the liquid nitrogen for 20 min and was finally immersed in the liquid nitrogen. They were cryopreserved for seven days; then, sperm parameters including sperm motility evaluation, motility characteristics, viability, DNA and plasma membrane integrity, total antioxidant capacity (TAC), reduced glutathione content (GSH), antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT] and glutathione peroxidase [GPx]) activity malondialdehyde (MDA) levels were evaluated. This study showed that spermatozoa cryopreservation with 50, 30 and 70 µg/ml of DHPG concentrations had better progressive motility, Curvilinear Velocity, Linearity, viability, intact plasma membrane and the levels of TAC, GPx and GSH were higher than the control group. The 50, 30 and 70 µg/ml of DHPG concentrations led to the significant decrease of DNA damage compared to the control group. Total motility, average path velocity, straight-line velocity and CAT activity were significantly improved in 30 and 50 µg/ml of DHPG concentrations, compared to the control group. Also, the 50 and 30 µg/ml of DHPG concentrations, decreased MDA levels compared to the other groups, significantly. In conclusion, our study showed that the addition 50 µg/ml of DHPG to the canine semen extender improved the semen characteristics and oxidative markers in the cryopreservation process.     

Wintersweet (Chimonanthus praecox) toxicity in four goats

CASE HISTORY: A one-year-old female goat presented with acute onset of recumbency, seizures and vocalisation approximately 5 hours after being given access to branch trimmings from a neighbour's garden. The plant from which the pruned branches came was subsequently identified as wintersweet (Chimonanthus praecox). Three other goats kept in the same paddock displayed similar clinical signs over a period of 4 hours following the initial presentation.

CLINICAL FINDINGS: All four goats were ataxic, displayed tetanic seizures and were in lateral recumbency; they had dilated pupils and were hyperaesthetic, with elevated heart and respiratory rates. After symptomatic treatment, including sedation with diazepam, one of the three goats continued to deteriorate and was subjected to euthanasia. The remaining three goats recovered over 1–14 days with nursing care and physiotherapy.

DIAGNOSIS: Toxicity due to ingestion of wintersweet, which contains the alkaloid calycanthine.

CLINICAL RELEVANCE: Calycanthine is a central nervous system toxin, causing convulsions. Wintersweet shrubs are present in many New Zealand gardens. Practitioners should be aware that the seeds and flowers, and possibly the leaves, of this plant are highly toxic with signs of toxicity including ataxia, hyperaesthesia and seizures.     

Tillage practices improve rice yield and soil phosphorus fractions in two typical paddy soils

Journal of Soils and Sediments - This research was undertaken (I) to evaluate the status of phosphorus fractions in paddy soils in response to different tillage management practices under different...     

Maternal behavior in the rat: facilitation through gonadectomy

Virgin rats were ovariectomized and tested for induction of maternal behavior by being housed with neonatal young. A postoperative interval of 8 weeks yielded an average latency for the onset of maternal behavior significantly lower than that for intact controls or for virgin females ovariectomized 4 weeks before testing. Replacement of estrogen in the group ovariectomized for 8 weeks or injection of the estrogen antagonist ethamoxytriphetol (MER-25) in the group ovariectomized for 4 weeks changed the average latencies accordingly. Parallel results were obtained for males that were castrated 4 or 8 weeks before testing. It is concluded (i) that maternal behavior is under gonadal control and that this control is normally inhibitory; and (ii) that only after long-term removal of the gonads, resulting presumably in the complete clearance of estrogen and testosterone, is the maternal mediating system finally released from steroid suppression.