Use of geoinformation and neurotechnology to assess and to forecast the humus content variations in the steppe soils

This paper reports the results obtained using the systemic basin approach, geoinformation, and neurotechnology for modeling and forecasting of the humus spatial inhomogeneity and content variations in the steppe and dry steppe zones (Kherson oblast, Ukraine). The general trend of such variations has been determined in the 0–40 cm layer for 42 years. The intensive use of irrigation and drainage activities in 1970–1989 resulted in a significant humus depletion by 0.36% on average (from 2.56% to 2.2%). The analysis in 4450 observation points has yielded a decrease in the variability, the rising polynomial dependence of the humus enrichment from the west to the east, and the logarithmic dependence from the south to the north. The neurotechnological modeling has made it possible to develop the artificial neural network for the spatiotemporal modeling of the humus content in the soils. The humus is predicted to be subject to the irreversible process of gradual depletion in the 0–40 layer until 2025 upon the use of the existing agrotechnologies: rainfed land by 0.01%/year and irrigated land by 0.03%/year. This result defines the territorial priorities of the regional policy and suggests the differentiated efficiency evaluation of the soil-protective unit of the farming systems.     

Relationship between Polyamines and Other Cold‐induced Response Mechanisms in Different Cereal Species

To find a connection between polyamines and various protective effectors involved in the development of cold tolerance, eight different cereal genotypes, including wheat, barley and oat species, were investigated during the acclimation phase to low temperature. Exposure to low temperature induced different changes in the levels of polyamines, and other signalling molecules, such as salicylic acid and abscisic acid, and of other protective compounds, namely flavonols, sugars and antioxidant enzyme activity, and in the lipid composition of certain membrane factions. The most remarkable differences were observed in the oat varieties compared to the other cereal genotypes, which was manifested in the lack of spermidine accumulation and of decrease in trans‐Δ³‐hexadecanoic acid content, in lower initial and not cold‐inducible abscisic acid content and guaiacol peroxidase activity after cold treatment. Correlation analysis revealed that spermidine shows strong positive relationship with flavonols, abscisic acid and ascorbate peroxidase, while was in negative relationship with trans‐Δ³‐hexadecanoic acid. These results suggest that spermidine may have a crucial role in the cold acclimation signalling processes in cereals.     

Differences in Ion Accumulation and Salt Tolerance among Glycine Accessions

Salinity reduces crop yield by limiting water uptake and causing ion‐specific stress. Soybean [Glycine max (L.) Merr.] is sensitive to soil salinity. However, there is variability among soybean genotypes and wild relatives for salt tolerance, suggesting that genetic improvement may be possible. The objective of this study was to identify differences in salt tolerance based on ion accumulation in leaves, stems and roots among accessions of four Glycine species. Four NaCl treatments, 0, 50, 75 and 100 mm , were imposed on G. max, G. soja, G. tomentella and G. argyrea accessions with different levels of salinity tolerance. Tolerant genotypes had less leaf scorch and a greater capacity to prevent Na⁺ and Cl^? transport from soil solution to stems and leaves than sensitive genotypes. Magnitude of leaf injury per unit increase in leaf Na⁺ or Cl^? concentrations was lower in tolerant than in susceptible accessions. Also, plant injury was associated more with Na⁺ rather than with Cl^? concentration in leaves. Salt‐tolerant accessions had greater leaf chlorophyll‐meter readings than sensitive genotypes at all NaCl concentrations. Glycine argyrea and G. tomentella accessions possessed higher salt tolerance than G. soja and G. max genotypes.     

Field‐grown Cotton Exhibits Seasonal Variation in Photosynthetic Heat Tolerance without Exposure to Heat‐stress or Water‐deficit Conditions

Thermotolerance acclimation of photosystem II to heat and drought is well documented, but studies demonstrating developmental impacts on heat tolerance in field‐grown plants are limited. Consequently, climatic variables, estimated canopy temperature, predawn leaf water potential (Ψ_PD), and the temperature responses of maximum quantum yield of photosystem II (F_v/F_m), variable fluorescence (F_v/F₀), quantum yield of electron transport (φ_Eο) and efficiency of PSI electron acceptor reduction (REο/ABS) were characterized for Gossypium hirsutum at three sample times during the growing season (21 June, 2 July and 18 July 2013) under well‐watered conditions. The temperature decreasing a given photosynthetic parameter 15% from the optimum is referred to as T₁₅ and served as a standardized measure of heat tolerance. Ambient and estimated canopy temperatures were well within the optimal range for cotton throughout the sample period, and leaves were verified well watered using Ψ_PD measurements. However, T₁₅ varied with sample date (highest on July 2 for all parameters), being 2 °C (F_v/F₀) to 5.5 °C (φ_Eο) higher on July 2 relative to June 21, despite optimal temperature conditions and predawn leaf water potential on all sample dates. These findings suggest that even under optimum temperature conditions and water availability, heat tolerance could be influenced by plant developmental stage.     

Field Evaluation of Cocksfoot,Tall Fescue and Phalaris for Dry Marginal Environments of South‐Eastern Australia. 1. Establishment and Herbage Production

Newly developed candidate cultivars of cocksfoot (Dactylis glomerata L.), phalaris (Phalaris aquatica L.) and tall fescue (Festuca arundinacea Schreb. = syn. L. arundinaceum (Schreb) Darbysh.) were evaluated over four years for persistence and productivity against current commercial cultivars in small plots at five locations selected for lower and less reliable rainfall and difficult soils (low pH and high Al) in south‐eastern Australia known to be marginally too dry for these grass species. The five locations were ‐ representing summer dominant rainfall, Inverell, in northern New South Wales (NSW); ‐ representing uniform rainfall; Trungley Hall, (medium rainfall), and Beckom (lower rainfall) both in southern NSW; and; representing a winter dominant pattern ‐ Eversley, (higher rainfall), and Bealiba, (lower rainfall), in central Victoria. The objective was to determine if the new candidate cultivars were more likely to persist and to be productive than current commercial cultivars. The study showed that most phalaris and cocksfoot treatments were highly productive in high rainfall years at one or both sites in southern NSW. However, all treatments had become much less productive by the end of the experimental period due to plant loss under hot, dry conditions in the final summer. At Bealiba in central Victoria, cocksfoot was the most productive species with several cocksfoot treatments of both subsp. hispanica and subsp. glomerata still present at the final harvest despite a hot and dry final summer‐autumn. Tall fescue was the most productive species in the two higher rainfall environments (Inverell, Eversley) although most treatments of all species performed well at those sites. Continental tall fescues were more productive on average than Mediterranean tall fescues at the strongly acidic Eversley site. As a result of this work, two of the new cocksfoot candidates (Moroccan Fine and AVH48 Selection) and one of the tall fescue candidates (Summer Active 1) have been licensed for commercial development and release.     

Characterizing long-term forest disturbance history and its drivers in the Ning-Zhen Mountains,Jiangsu Province of eastern China using yearly Landsat observations (1987–2011)

Forest losses or gains have long been recognized as critical processes modulating the carbon flux between the biosphere and the atmosphere. Timely, accurate and spatially explicit information on forest disturbance and recovery history is required for assessing the effectiveness of existing forest management. The major objectives of our research focused on testing the mapping efficacy of the vegetation change tracker (VCT) model over a forested area in China. We used a new version of VCT algorithm built upon the Landsat time series stacks (LTSS). The LTSS consisted of yearly image acquisitions to map forest disturbance history from 1987 to 2011 over the Ning-Zhen Mountains, Jiangsu Province of east China. The LTSS consisted of TM and ETM+ scenes with different projections due to distinct data sources (Beijing remote sensing ground station and the USGS EROS Center). The validation results of the disturbance year maps showed that most spatial agreement measures ranged from 70 to 86 %, comparable with the VCT accuracies reported for many places in USA. Very low accuracies were identified in 1995 (38.3 %) and 1992 (56.2 %) in the current analysis. These resulted from the insensitivity of the VCT algorithm to detect low intensity disturbances and also from the mis-registration errors of the image pairs. Major forest disturbance types existing in our study area were identified as agricultural expansion (39.8 %), urbanization (24.9 %), forest management practice (19.3 %), and mining (12.8 %). In general, there was a gradual decreasing trend in forest cover throughout this region, caused principally by China’s economic, demographic, environmental and political policies and decisions, as well as some weather events. While VCT has largely been used to assess long term changes and trends in the USA, it has great potential for assessing landscape level change elsewhere throughout the world.     

Effects of forage type and gibberellic acid on nitrate leaching losses

Nitrogen (N) leaching from soil into water is a significant concern for intensively grazed forage‐based systems because it can cause a decline in water quality and is a risk to human health. Urine patches from grazing animals are the main source of this N. The objective of this study was to quantify the effect that forage type and gibberellic acid (GA) application had on N leaching and herbage N uptake from urine patches on perennial ryegrass–white clover (RGWC), Italian ryegrass and lucerne. A lysimeter study was conducted over 17 months to measure herbage growth, N uptake and N loss to water beneath each of the three forage types with the following treatments: control, urine (700 kg N/ha) and urine with GA (8 g GA active ingredient/ha). Compared with RGWC (205 kg N/ha), N leaching losses were 35.3% lower from Italian ryegrass (133 kg N/ha) and 98.5% higher from lucerne (407 kg N/ha). These differences in leaching loss are likely to be due to winter plant growth and N uptake. During the winter months, Italian ryegrass had higher N uptake, whereas lucerne had lower N uptake, compared with RGWC. The application of GA had no effect on N leaching losses, DM yield or N uptake of forage treated with 700 kg N/ha urine.