Dynamics of macronutrients in olive leaves

The study aims to track the dynamics of the olive leaf nitrogen (N), phosphorus (P) and potassium (K) for five olive varieties under drip irrigation in farmer's fields in central Morocco. Leaf sampling was done every month from May 2014 to April 2015. Leaf macronutrients contents showed variation over time. Olive leaves have maintained the same N content throughout the study period indicating a continuing olive uptake of nitrogen. Higher leaf P absorption was observed during flowering and fruit magnification periods indicating the important P needs of olive during these periods. Olive leaf K levels were higher from September to December indicating the high K needs of olive. No variety effect was revealed on the leaf N, P and K contents. Very highly significant differences were found between the leaf N and K levels measured at different sampling periods. The leaf P concentration was statistically equal in all measuring periods.     

Selection of diverse parents of chickpea (Cicer arietinum L.) by multivariate analysis and the degree of heterosis of their F1 hybrids

Summary Studies on genetic diversity in chickpea (Cicer arietinum L.) indicated the existence of considerable amount of variation for grain yield and its components in the material. One hundred and thirty two genotypes fell into eight clusters. The covariation structure studied by means of factor analysis indicated the possibility of obtaining, through hybridization, genotypes physiologically and morphologically more efficient. Multivariate analysis of data from 7 parents and 21 F1 hybrids indicated weak correspondence between D²-analysis and canonical variate analysis. As there was no relationship between heterosis over midparent and genetic distance between the parents, so the traditional approach of making a large number of crosses is being suggested.     

Comparison of New Ultrasonic Digestion Approaches for Plant Matrices in the Analysis of Trace Metals by Inductively Coupled Plasma–Optical Emission Spectroscopy Analysis: Contrast with USEPA Method 3050B

An ultrasonic method using two approaches, A and B, along with a reference Environmental Protection Agency (EPA) Method 3050B [i.e., a mixture of 30 mL of nitric acid–hydrochloric acid–hydrogen peroxide–water (HNO₃-HCl-H₂O₂-H₂O)] were contrasted for leaching of a plant matrix. The trace metals were arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, nickel, lead, selenium, and zinc (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Se and Zn) and quantified by ICP-OES followed by an investigation into residue formation and the impact of digestion time. Approach B was the most accurate and precise with percent recoveries ranging between 99 and 120%, whereas ultrasonic approach A and the USEPA method 3050B gave similar results with poor accuracies and precisions. In the optimization of the digestion time using approach B, the total metal recovery was fairly the same over a period of 120 min except for Cr and Cu, which showed slight variations.     

Comparison of leaf and pod disease reactions of beans (Phaseolus vulgaris L.) inoculated by different methods with strains of Xanthomonas campestris pv. Phaseoli (Smith) dye

Summary Common blight disease in beans (Phaseolus vulgaris), caused by the bacterium Xanthomonas campestris pv. phaseoli, reduces crop yield and seed quality. Information is needed on the variation of leaves and pods disease reaction to strains of the bacterium after different inoculation methods. Phaseolus vulgaris cultivars Red Kidney Charlevoix, GN Harris, GN 1140, and GN Emerson were inoculated with three different strains of Xanthomonas campestris pv. phaseoli at two inoculum concentrations (10⁸ and 10⁶ bacterial cells/ml) using water soaking, multiple needle, and razor blade inoculation on leaves, and razor blade scratch, dissecting needle, and razor blade cut inoculation on pods. Differential cultivar disease reactions of leaves, pods, or both to the bacterial strains were observed in some cases. Significant interactions among cultivars, inoculation methods, strains, and inoculum concentrations (leaves) were found. A rapid leaf chlorosis developed 6 to 7 days after inoculation. Strains of bacteria did not show specificity in inducing this reaction, but rapid leaf chlorosis was associated with high inoculum concentration and with the water soaking and multiple needle methods. Another experiment was conducted to count the number of living bacterial cells deposited in the leaf tissue after inoculation by different methods. The number of bacteria deposited by water soaking or multiple needle was higher than that deposited by razor blade.Published as Paper No. 8584, Journal Series, Nebraska Agricultural Experiment Station. Research was conducted under Project No. 20–36.     

The Cytological Status of Plants Regenerated from Shoot-Meristem Culture of Pisum sativum L

The cytological status of plantlets regenerated from shoot apical meristems of Pisum sativum was investigated. Chromosome counts in root apices of in vitro regenerated plants showed a preponderance of diploid cells. Moreover, the karyotypes of root-tips from plants derived from culture and from normal plants were basically the same. Topics such as the treatment of chromosomal armlength data, simple statistical comparison of samples derived from normal and regenerated plants are discussed.     

Optimizing supplemental irrigation: Tradeoffs between profitability and sustainability

Water production functions are used to model yield response to various levels of supplemental irrigation (SI), to assess water productivity coefficients, and to identify optimum irrigation under various input-output price scenarios. The SI production function is taken as the difference between the total water production function (irrigation + rain) and that of rainwater. Theoretical analysis of the unconstrained objective function shows that the seasonal depth of SI to maximize profit occurs when the marginal product of water equals the ratio of unit water cost to unit product sale price. Applying this analysis to wheat in northern Syria, the production functions of SI under different rainfall conditions are developed. Coupled with current and projected water costs and wheat sale prices, the functions are used to develop an easy-to-use chart for determining seasonal irrigation rates to maximize profit under a range of seasonal rainfall amounts.Results show that, for a given seasonal rainfall, there is a critical value for the ratio of irrigation cost to production price beyond which SI becomes less profitable than rainfed production. Higher product prices and lower irrigation costs encourage the use of more water. Policies supporting high wheat prices and low irrigation costs encourage maximizing yields but with low water productivity. The resulting farmer practice threatens the sustainability of water resources. Balancing profitability versus sustainability is a challenge for policy makers. Our analysis can help national and local water authorities and policy makers determine appropriate policies for water valuation and allocation; and assist extension services and farmers in planning irrigation infrastructure and farm water management.     

Indicators of soil quality and crop productivity assessment at a long-term experiment site in the lower Indo-Gangetic plains

Deterioration of soil quality under resource-intensive modern agriculture in the face of global climate change poses a huge risk to food security. Because of the complex nature, estimators of soil quality often rely upon a limited set of soil attributes, along with statistical data reduction techniques, for developing quality indices, whilst overlooking biological aspects and regional climatic variability. This study screened the most suitable soil quality indexing approaches for a rice-oilseed-based cropping system in the lower Indo-Gangetic plains (IGP). For this, surface soil samples (0–15 cm) were collected from an ongoing long-term fertilizer experiment with a rice-mustard-sesame cropping system in the IGP. The following treatments were assessed for their effect on soil quality: T₁-control, T₂-NPK (recommended NPK doses), T₃-NPKG (NPK + in situ green manuring), T₄-NPKGB (NPK + in situ green manuring + biofertilizer) and T₅-NPKF (NPK + farm yard manure FYM). We found that total organic carbon (TOC), β-glucosidase, CaCl₂ extractable S, alkaline KMnO₄ oxidizable N, activity of urease, amidase enzyme and mean weight diameter (MWD) were sensitive key indicators of soil quality. The NPKF treatment maintained the highest soil quality status (0.80–0.91), both under productivity and environmental protection goals, owing to the availability of decomposable carbon. Regression analysis showed a better agreement of equivalent rice yield with expert opinion (EO; R² = 0.89) than principal component analysis (PCA; R² = 0.76). Finally, we found that the expert opinion approach with the nonlinear scoring function was the best tool for soil quality assessment of the region.     

Resistant Starch Content Is Related to Granule Size in Barley

Physical properties of resistant starch (RS) were examined in a range of barley genotypes to determine the contribution of starch and seed physical characteristics to the RS component. Thirty‐three barley genotypes were studied, which varied significantly in their RS, amylose, and starch contents and grain yield. From 33 genotypes, 13 exhibiting high RS were selected for detailed physicochemical analysis of starch. In high‐RS varieties, granule size and number were unimodal, compared with normal starches from a reference genotype, which showed a bimodal distribution. Principal component analysis (PCA) showed that a higher content of granules <15 µm was positively correlated with RS and amylose content, whereas the proportion of granules 15–45 µm was negatively correlated with the RS and amylose contents. Physical fractionation of starches by centrifugation into different population sizes demonstrated that size alone is not an accurate indicator of the population of A‐type and B‐type granules within a given genotype. PCA also showed that large 15–45 µm granules were positively correlated with seed thickness and that thousand grain weight was positively correlated with seed width. High‐RS and high‐amylose genotypes showed variation in overall yield and starch content, with some genotypes showing yield comparable to the reference genotype. Analysis of amylopectin chain length distribution showed that high amylose or RS content was not associated with a higher proportion of amylopectin long chains when compared with either waxy or reference (normal) barley genotypes. This study highlights useful markers for screening barley genotypes with favorable starch characteristics.     

Combined effect of deficit irrigation and potassium fertilizer on physiological response,plant water status and yield of soybean in calcareous soil

A 2-year field experiment (2013 and 2014) was conducted in calcareous soil (CaCO₃ 19.2%), on soybean grown under three irrigation regimes 100%, 85% and 70% of crop evapotranspiration combined with three potassium (K₂O) levels (90, 120 and 150 kg ha^?1). The objective was to investigate the complementary properties of potassium fertilizer in improving soybean physiological response under water deficit. Plant water status (relative water content RWC, chlorophyll fluorescence F_v/F₀ and F_v/F_m), had been significantly affected by irrigation or/and potassium application. Potassium improved growth characteristics (i.e. shoot length, number, leaf area and dry weight of leaves) as well as physiochemical attributes (total soluble sugars, free proline and contents of N, P, K, Ca and Na). Yield and yield water use efficiency (Y-WUE) were significantly affected by irrigation and potassium treatments. Results indicated that potassium application of 150 and 120 kg ha^?1 significantly increased seed yield by 29.6% and 13.89%, respectively, compared with 90 kg ha^?1 as average for two seasons. It was concluded that application of higher levels of potassium fertilizer in arid environment improves plant water status as well as growth and yield of soybean under water stress.     

Impact of a Variable Tungsten Pollution on the Elemental Uptake of Two Plant Species

A radish and a grass species were grown in identical substrates either unpolluted or polluted by tungsten (W) at 1, 5, and 10 μg/g levels of watering solutions during 1 month under controlled laboratory conditions. Initially, at 4.1 μg/g, the W content in grass leaves reached 16 μg/g at the highest rate of W supply to the substrate. For radish, the content of W reached 22 and 29 μg/g in the leaves and roots, respectively. The overall W pollution increased significantly the mobility of major elements from substrate to grass leaves, especially at the 5 μg/g pollution level, whereas the W impact on radish leaves resulted in an increase of most contents, only Mn remaining unaffected. The roots from polluted radishes were enriched in Si by 21% and Al by 42% at low pollution, and in Si by 15% at high supply, whereas the uptake of the other elements remained unchanged. It looks like the W pollution at the levels chosen does not impact the transfer of the major and trace elements from roots to leaves of Raphanus sativus. Alternatively, metallic trace elements (Ba, Ni, Cr, Zn, W, Co) of the Raphanus sativus and Chloris gayana leaves outline similar content changes depending on the amount of W pollution. The total rare-earth element contents of the leaves of Raphanus sativus grown in the polluted substrates are lower than those of the leaves from unpolluted substrate. Their normalization in the leaves and roots of Raphanus sativus from the polluted substrates to those of the radish from non-polluted substrate provides flat patterns for both with a positive Eu anomaly for leaves, as for those of the grass and a negative Gd anomaly for roots. Also, addition of soluble W to the substrates induced an increase in the bacterial activity of the soil.