Plant training for induced defense against insect pests: a promising tool for integrated pest management in cotton

Enhancing cotton pest management using plant natural defenses has been described as a promising way to improve the management of crop pests. We here reviewed various studies on cotton growing systems to illustrate how an ancient technique called plant training, which includes plant topping and pruning, may contribute to this goal. Using examples from cotton crops, we show how trained plants can be brought to a state of enhanced defense that causes faster and more robust activation of their defense responses. We revisit the agricultural benefits associated with this technique in cotton crops, with a focus on its potential as a supplementary tool for integrated pest management (IPM). In particular, we examine its role in mediating plant interactions with conspecific neighboring plants, pests and associated natural enemies. We propose a new IPM tool, plant training for induced defense, which involves inducing plant defense through artificial injury. Experimental evidence from various studies shows that cotton training is a promising technique, particularly for smallholders, which can be used as part of an IPM program to significantly reduce insecticide use and to improve productivity in cotton farming. © 2018 Society of Chemical Industry     

Increased moisture and methanogenesis contribute to reduced methane oxidation in elevated CO2 soils

Awareness of global warming has stimulated research on environmental controls of soil methane (CH₄) consumption and the effects of increasing atmospheric carbon dioxide (CO₂) on the terrestrial CH₄ sink. In this study, factors impacting soil CH₄ consumption were investigated using laboratory incubations of soils collected at the Free Air Carbon Transfer and Storage I site in the Duke Forest, NC, where plots have been exposed to ambient (370 μL L⁻¹) or elevated (ambient + 200 μL L⁻¹) CO₂ since August 1996. Over 1 year, nearly 90% of the 360 incubations showed net CH₄ consumption, confirming that CH₄-oxidizing (methanotrophic) bacteria were active. Soil moisture was significantly (p < 0.01) higher in the 25–30 cm layer of elevated CO₂ soils over the length of the study, but soil moisture was equal between CO₂ treatments in shallower soils. The increased soil moisture corresponded to decreased net CH₄ oxidation, as elevated CO₂ soils also oxidized 70% less CH₄ at the 25–30 cm depth compared to ambient CO₂ soils, while CH₄ consumption was equal between treatments in shallower soils. Soil moisture content predicted (p < 0.05) CH₄ consumption in upper layers of ambient CO₂ soils, but this relationship was not significant in elevated CO₂ soils at any depth, suggesting that environmental factors in addition to moisture were influencing net CH₄ oxidation under elevated CO₂. More than 6% of the activity assays showed net CH₄ production, and of these, 80% contained soils from elevated CO₂ plots. In addition, more than 50% of the CH₄-producing flasks from elevated CO₂ sites contained deeper (25–30 cm) soils. These results indicate that subsurface (25 cm+) CH₄ production contributes to decreased net CH₄ consumption under elevated CO₂ in otherwise aerobic soils.     

Sediment yield variability in Northern Ethiopia: A quantitative analysis of its controlling factors

In Tigray-northern Ethiopia, lack of sediment yield data and appropriate methodologies for predicting sediment yield have contributed to poor planning resulting in rapid sedimentation in reservoirs and storage capacity loss. The objectives of this study were: (1) to assess the spatial variability of absolute sediment yield (SY) and area-specific sediment yield (SSY) and to identify their controlling factors for 11 representative catchments and (2) to develop models to predict sediment yield. We quantified sediment yield from reservoir sediment surveys and studied the role of bio-physical characteristics of the catchments and their interactions in controlling SY and SSY variability.     

Diachronic (1979–2003) analysis of rice genetic diversity in Guinea did not reveal genetic erosion

Greater insight into the dynamics of genetic resources of crop plants is needed in order to pinpoint detrimental evolutionary patterns and draw up conservation priorities. Temporal evolution of rice genetic diversity was monitored in Maritime Guinea where subsistence-oriented agriculture prevails. Diachronic comparison was performed between samples collected in six villages during the 1979/1982-period and in 2003, based on the names and number of varieties inventoried and the polymorphism of microsatellite markers. The number of varieties appeared not to be comparable between the two dates, due to differences in the collection methods. The varietal composition had evolved very substantially between the two collection dates. Many long-duration varieties present in 1979/1982 had been abandoned and several improved varieties had been introduced. The mean number of alleles per locus and per accession was significantly higher in accessions collected in 2003. Pairwise comparisons of the mean number of alleles per locus in 1979/1982–2003 homonymous accession pairs indicated higher intra-accession diversity for the 2003 collections. Genetic differentiation, measured with the F _ST values, was very high and significant for more than 80% of these pairs of accessions. The overall genetic differentiation between accessions from the two collections dates was also significant. Significant changes were also observed for allelic composition. However, alleles specific of each collection date had much lower frequency, compared to alleles common to the two collection dates. These results suggest that rice genetic diversity in Maritime Guinea has been maintained or even enhanced. Old collections of crop genetic resources are often not exhaustive enough to undertake perfect diachronic comparison. New methods to utilize this historical data for diversity monitoring are needed.     

Soil construction: A step for ecological reclamation of derelict lands

Goal, Scope and Background  Efficient and environmentally friendly technologies for soil reclamation require efforts to develop innovative processes. Alternative technologies to drastic techniques (containment, total removal of soil) are receiving increasing interest. They are based either on the use of ameliorants (e.g. lime, fertilizer, organic mulch) and more recently on the spreading of organic wastes (e.g. compost, sewage sludge). This paper presents a new process of soil construction using wastes and industrial by-products which are formulated and stacked in layers to build a new soil profile over in situ degraded substrates. Work was conducted to assess the feasibility of the ecological reclamation, focusing on the major functions of constructed Technosols. Materials and Methods  Two large lysimetric plots (10 × 10 m) were built on a former coking plant, and two strategies of constructed soil profiles were compared: i) a control soil using thermally treated industrial soil available in situ, and ii) a constructed soil with a combination of thermally treated industrial soil mixed with exogenous materials such as green waste compost and paper mill sludge. Rainfall was measured periodically, drainage effluent was collected, and aliquots were sampled per plot. Plants were collected in 8 replicates for each plot. Results  Water balance data showed that about 10% of the rain water percolated through the constructed soil profiles. Drainage effluent contained a low concentration of contaminants, below the French water drinking standards. Plants grew without any deficiency symptoms on both plots. Apart from the sowed plants, indigenous species developed on the constructed Technosols. Discussion  The experimental set-up was representative of the real conditions for the implementation of such reclamation technologies. In spite of the significant concentrations of trace elements in the parent materials, the fluxes in the drainage effluent were very low because of the high pH. Significantly higher biomass values were recorded on the constructed soil than on the control, as well as a better development of indigenous plants. Conclusions  The constructed soils are examples of Technosols as they are made exclusively of technogenic parent materials. Our results showed that they can behave like natural soils (water cycle, trace elements filtration, biomass production). The process of soil construction is not only an efficient way to reclaim derelict lands, but also a safe alternative for the recycling of wastes and by-products with a minimum use of unpolluted and fertile agricultural soil. Recommendations  The restoration of soil functions, thanks to the soil construction process, must be considered as a primary step for the ecological reclamation of derelict lands. In this way, the pedo-engineering approach should be considered as an essential part of the global ecological engineering for the reclamation of derelict lands. Perspectives  Two major outlooks appear: i) testing a larger variety of wastes and by-products as parent materials for different constructed soils, ii) generalize the results on constructed soils to the characterization of Technosols. ESS-Submission Editor: Dr. Stefan Norra (stefan.norra@img.uka.de)     

Consideration of soil in urban planning documents—a French case study

Journal of Soils and Sediments - Given their increasing importance, soils should be considered as valuable resources by those involved in urban planning. Indeed, soils are expected to be...     

PAH biodegradation by telluric saprotrophic fungi isolated from aged PAH-contaminated soils in mineral medium and historically contaminated soil microcosms

Journal of Soils and Sediments - Remediation of contaminated soils is of high relevance considering losses of this limited resource in most countries through erosion or through destruction for...     

Preoperative prognostic indicators in cattle with abomasal volvulus

A prospective study evaluating preoperative prognostic indicators in 80 cattle with abomasal volvulus was done. Surgical correction of the abomasal volvulus was performed in all animals. After surgery, cattle were categorized into 3 groups: productive (acceptable milk production or appetite, n = 59), salvaged (poor milk production or appetite, n = 10), and nonsurvivors (n = 11). Mean values for study variables did not differ significantly between salvaged and nonsurvivor groups. Cattle in these 2 groups were combined to form a nonproductive group, which was compared with the productive group. Productive cattle had a significantly lower preoperative heart rate than nonproductive cattle, were less dehydrated, had lower serum alkaline phosphatase (ALP) activity and serum creatinine concentration, more frequent rumen contractions, higher serum Na+ and Cl- concentrations, and had been inappetent for a shorter period. Significant differences were not detected in blood pH, base excess, anion gap, PCV, and serum K+ concentrations between the 2 groups. Feces from nonproductive cattle tended to be reduced in volume and were significantly darker. A number of preoperative prognostic indices were evaluated by calculating the sensitivity, specificity, and positive predictive value (+PV) of each variable and by using logistic regression. Positive predictive values were generally higher in identifying productive cattle than nonproductive cattle.(ABSTRACT TRUNCATED AT 250 WORDS)