Irrigation and Salinity: a Perspective Review of the Salinity Hazards of Irrigation Development in the Arid Zone

Irrigation development in the arid zone almost alwayshas to deal with not only secondarysalinity but also with primary and fossilsalinity. In many cases, irrigationdevelopment brings about large scalechanges in the local geohydrological regimewhich often result in mobilization of saltsstored in the underlying substrata. Thisprimary and fossil salt mobilization hasbeen found to be one of the principalcauses of rivers salinization in irrigatedbasins in the arid zone. The paperhighlights this hitherto insufficientlyrecognized salinity hazard and discussesrelated control measures and strategies.     

Efficiency of Foliar Versus Granular Fertilization: A Field Study of Creeping Bentgrass Performance

ABSTRACT

Limited information comparing foliar versus granular fertilization of turfgrasses is available. The objective of this research was to evaluate liquid and/or granular N fertilization on turfgrass quality, clipping yield, and root biomass of ‘L-93’ creeping bentgrass. Treatments consisted of two annual nitrogen (N) inputs, 127 and 190 kg ha^?1, using 100% granular urea fertilizer, 50% granular urea + 50% liquid urea fertilizer, or 100% liquid urea fertilizer. These results suggest a rate of at least 190 kg N ha^?1 yr^?1 is needed to maintain acceptable bentgrass quality in the transition zone of the U.S. Combining both liquid and granular methods appear superior compared to relying on one method exclusively.     

Host Traits Influencing Severity of White Mold of Potatoes in a Rainfed Environment

Differences among cultivars of Solanum tuberosum L. in susceptibility to Sclerotinia sclerotiorum (Lib.) de Bary have been noted through observation and research. Traits hypothesized as having a potential effect upon susceptibility included, flower propensity, time to 50 % flowering, flowering duration, canopy density, oxalic acid sensitivity, and maturity. Field plots were planted using seven cultivars in which these variables were quantified and analyzed. Identification of those factors providing the greatest amount of information towards disease severity were identified using multiple linear regression, and parameter selection using Akaike’s Information Criterion. The factors of maturity (R²?=?0.77), time to 50 % flower (R²?=?0.64), and oxalic acid sensitivity (R²?=?0.57) were identified as providing the greatest predictive indices of white mold severity in potatoes.     

Sarcomatoid renal cell carcinoma with scant epithelial components in an Angora cat

CASE HISTORY: A 6-year-old, neutered, female Angora cat presented with a history of lethargy and anorexia for 2 months and a clinically palpable and gradually enlarging, solid mass in the abdominal cavity extending from the last costal arch to the pelvic cavity.

CLINICAL FINDINGS: Examination of the cat revealed jaundice, dehydration and hypothermia. Haematological manifestations included lymphopenia and substantial decrease in haematocrit value. Biochemical analysis of the blood revealed hypoglycaemia, three-fold elevated blood urea nitrogen values, increased level of serum aspartate aminotransferase and increased total bilirubin while the creatinine level was normal. Ultrasonographic examination of the abdomen showed a disrupted and large hypoechoic area around the left kidney. The cat was anaesthetised and the left kidney was removed, but the cat died following surgery.

PATHOLOGICAL FINDINGS: On post-mortem examination, the left kidney was markedly enlarged and both the cortical and medullary parenchyma were replaced by confluent, multilobulated, pale tan-white, firm nodular masses protruding above the capsular surface. Metastasis was not observed. Cytological examination revealed a population of spindle-shaped cells of variable size, with abundant coarse chromatin and occasionally prominent nucleoli. Initial sections of the kidney were indicative of undifferentiated sarcoma confirmed by immunohistochemistry revealing vimentin-positive and cytokeratin-negative results in all tumour tissues. Additional sections showed very small amounts of both cytokeratin-positive and vimentin-positive areas.

DIAGNOSIS: Sarcomatoid renal cell carcinoma (SRCC) with scant epithelial components originating from left kidney.

CLINICAL RELEVANCE: Clinical and pathological features were similar to those of human SRCC, even though there was no evidence of metastases. Immunohistochemistry for vimentin and cytokeratin may be useful for definitive diagnosis of renal cell carcinoma with sarcomatoid differentiation, although staining of sections from several different parts of the tumour may be necessary. When a primary renal tumour is presented, SRCC should be considered as this diagnosis may influence treatment protocols and the clinical outcome.     

Genetic diversity and parentage in farmer selections of cacao from Southern Sulawesi,Indonesia revealed by microsatellite markers

Indonesia is the third largest cocoa-producing country in the world. Knowledge of genetic diversity and parentage of farmer selections is important for effective selection and rational deployment of superior cacao clones in farmers’ fields. We assessed genetic diversity and parentage of 53 farmer selections of cacao in Sulawesi, Indonesia, using 152 international clones as references. Cluster analysis, based on 15 microsatellite markers, showed that these Sulawesi farmer selections are mainly comprised of hybrids derived from Trinitario and two Upper Amazon Forastero groups. Bayesian assignment and likelihood-based parentage analysis further demonstrated that only a small number of germplasm groups, dominantly Trinitario and Parinari, contributed to these farmer selections, in spite of diverse parental clones having been used in the breeding program and seed gardens in Indonesia since the 1950s. The narrow parentage predicts a less durable host resistance to cacao diseases. Limited access of the farmers to diverse planting materials or the strong preference for large pods and large bean size by local farmers, may have affected the selection outcome. Diverse sources of resistance, harbored in different cacao germplasm groups, need to be effectively incorporated to broaden the on-farm diversity and ensure sustainable cacao production in Sulawesi.     

Age Dependent Resistance to Transmissible Gastroenteritis of Swine (TGE) II. Coronavirus Titer in Tissues of Pigs After Exposure

Coronavirus titers were compared in various tissues of three-day old and 21-day old pigs after exposure to the virus of transmissible gastroenteritis (TGE). Pigs in both groups that did not die from TGE were necropsied at intervals from one to 15 days post-exposure, and their tissues assayed for viral content. Viral titers were much higher in the small intestines of the younger pigs. Viral isolations were obtained from several tissues of the younger pigs but only from the small intestines of pigs infected at 21 days of age. Levels of viral neutralizing antibodies in the serums of both age groups were comparable at similar post-exposure intervals.     

Long term accumulation of nitrogen in soils of dry mixed eucalypt forest in the absence of fire

In the Eden area in NSW, Australia, low fertility granitic surface soils were sampled from 156 sites and analysed for pH, organic C, total N, total P, available P, exchangeable bases and exchangeable Al. Fifty eight of these sites were also sampled to a depth of 40 cm. Time since fire ranged from 1 to 39 years and was used in the analysis as a surrogate for fire frequency. No information was available on fire intensity. No significant relationships were found between time since fire and P or base cations. However, the quantities of organic matter and total N (kg ha⁻¹), and the C/N ratio were significantly related to both time since fire alone and to the combination of time since fire and soil total P. Based on these relationships, it was estimated that there were average net increases of between 11 and 21 kg N ha⁻¹ year⁻¹ in surface soil, the actual quantity depending on the level of soil total P. There was little change in N in the initial 10 years after fire and there was a peak in N accumulation about 24 years after fire. The C/N ratio and surface soil pH decreased with time since fire. Accumulation of N and reductions in pH and C/N ratio were studied further in a small scale paired plot analysis. The repeatedly burnt plots had lower levels of both litter and understorey and the overstorey trees generally had healthier crowns than in the unburnt plots. The differences between the repeatedly burnt and the unburnt plots matched the models developed from the general survey. There were no significant changes in the C/N ratio, but the unburnt sites had higher levels of extractable mineral N and the relationships between the mineral N and the C/N ratio for burnt and unburnt sites were statistically significant. The quantities of extractable mineral N in the unburnt soils (2.3 kg N ha⁻¹) were about twice the levels in the burnt soils (1.2 kg N ha⁻¹). The pH of the surface soil (4.4 in 1:1 water) in the regularly burnt area was higher than in the unburnt area (pH 4.1) and the exchangeable aluminium also differed (0.62 c mol⁻¹ in the burnt area and 1.3 c mol⁻¹ in the unburnt). The combined data indicate that changes occur in forest soils when there is a long period of exclusion of fire. It is suggested that these changes generally lead to secondary changes, such as in pH and availability of other elements such as aluminium. The study highlights a number of issues including the rates of inputs of N to the system and the question of N saturation and its long term interaction with plant species. It is hypothesised that reduced burning leads to increased N availability and other soil changes which negatively impact on tree health.     

Inhibition of carotenogenesis by substituted diphenyl ethers of the m-phenoxybenzamide type

Diphenyl ethers exhibit different modes of action according to their chemical constitution. Diphenyl ethers of the m-phenoxybenzamide type, which were found to be effective on carotenogenesis resulting in an accumulation of colorless carotenoid precursors, mostly phytoene, indicative of inhibition of desaturation, are discussed. As seen with other carotenoid biosynthesis inhibitors, a concurrent loss of chlorophyll was observed as a secondary effect caused by the absence of protective carotenoids. In contrast to peroxidative p-nitrodiphenyl ethers like oxyfluorfen (2-chloro-4-trifluoromethylphenyl-3′-ethoxy-4′-nitrophenyl ether), the m-phenoxybenzamides assayed showed the same phytotoxic mode of action in the dark as observed when using heterotrophic Scenedesmus cultures. As expected, chlorophylls were not affected. The decrease of carotenoids was not due to their degradation but to inhibited carotenogenesis. Examination of carotenoid fractions show that the m-phenoxybenzamides, e.g., 3-(2,5-dimethylphenoxy)-N-ethylbenzamide, used here act similarly to 2-phenylpyridazinones like norflurazon [4-chloro-5-methylamino-2-(2-trifluoromethylphenyl)-pyridazin-3(2H)one]. All these inhibitors strongly decrease the α- and β-carotene content, while xanthophyll content is not lowered as much.