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AbstractThe objective of this study was to determine the share of nitrogen Agronomic Efficiency/Productivity components (recovery/uptake efficiency; RE × physiological/utilization efficiency; PE) in a common intercropping system (maize-bean) which until the current research, there is no information about it. A split plots arrangement based on the randomized complete block design (RCBD) with three replications, was carried out during two successive cropping years. The main plot factor consisted of sole cultivation of maize and bean, row intercropping with ratios including 50%:50% (1 row of maize: 1 row of bean), 67%:33% (2 rows of maize: 1 row of bean), and 33%: 67% (1 row of maize: 2 rows of bean). Application and non-application of nitrogen (N) fertilizer (55 kg ha−1) were assigned to the subplots. In both species, when NUE was calculated based on the seed yield, the N utilization efficiency (NUtE) was higher in all treatments compared with NUtE based on the dry matter yield. Under the conditions of N application, the ratio of 50:50 of bean: maize intercropped had higher N uptake efficiency (NUpE) for both species. Moreover, the ratio of 50:50 had the highest total land equivalent ratio (LER) based on the seed yield (1.10), the NUpE (2.30%), and NUE indices (1.98 kg kg−1 and 2.02 kg kg−1 based on the seed yield and the dry matter yield, respectively). The ratio of 50:50 of bean: maize intercropped having the highest efficiency indices, can be a lasting solution to reduce N application and losses, improving its uptake efficiency. Reducing the excessive use of chemical N fertilizer increases the productivity of this input in agroecosystems and reduces costs and health concerns. [ABSTRACT FROM AUTHOR]

Comparing the absorption and translocation efficiency of the nutrients in olive cultivars can lead to the selection of cultivars with higher efficiency. This research was conducted with the aim of comparing the uptake and translocation capacity in 20 olive cultivars (12 domestic and 8 foreign) in a commercial orchard on calcareous soil in a randomized complete block design. Except for copper (Cu), leaf concentration of other elements was within the optimal range. In ʻAmphesis,ʼ high translocation (5.28%) and in ʻAmigdalolia,' high uptake capacity (12.6) caused an increase in leaf phosphorus (P). Leaf K in all cultivars was higher than the deficiency limit (0.77%). In none of the cultivars, leaf sodium (Na) concentration was higher than the toxicity limit (0.2%), it accumulated in the root of ʻZard-Aliabadʼ and ʻShengeh,ʼ and reduced in their leaf. Leaf iron (Fe) concentration of all cultivars was in the sufficient range (>63 mg kg−1) and the highest was in ʻGorgan-Aʼ and ʻZardʼ and the lowest in ʻKazeroon,ʼ ʻArbequinaʼ and ʻMission.ʼ Although the leaf Cu in ʻAmphesisʼ (4.32 mg kg−1) and ʻArbequinaʼ (4.03 mg kg−1) was above the sufficient limit, in the rest of the cultivars it was below this critical limit. The highest leaf manganese (Mn) concentration (61.35 mg kg−1) and the highest Mn translocation percentage (84.59) were in ʻFeshomi.ʼ Among these cultivars, ʻAmphesisʼ was higher than others in terms of P, potassium (K), Cu and zinc (Zn) leaf concentrations and ʻAmigdalolia in terms of P, K and Zn, and in most cases the reason for this is the higher translocation efficiency. [ABSTRACT FROM AUTHOR]

This article presents the performance estimation of a single-stage vapor adsorption system employing various carbon-based adsorbents with ethanol refrigerant, coupled with a small-scale biomass-based heating unit for space cooling, refrigeration, and heat-pumping applications. A detailed parametric investigation highlights the effects of operating temperatures, and heat exchanger to adsorbent mass ratio on specific cooling energy (SCE), coefficient of performance (COP), uptake efficiency (ηu), and mass of adsorbent to combustion fuel (mad/mcf) to identify the suitable adsorbent and sorption bed designs for each application. The numerical findings reveal that the flat-finned tube (FFT) adsorber outperforms traditional-finned tube (TFT) and tube & shell-type (T&S) adsorbers, achieving 19% and 30% higher COP, respectively, with biomass carbon-ethanol pair. The H2-treated Maxsorb-III shows the greatest optimal cooling COP (0.73), followed by the biomass-carbon (0.72) for refrigeration and space cooling. For heat pumping applications, biomass carbon-ethanol achieves the highest heat pumping COP (1.84) at a desorption temperature of 90°C, surpassing H2-treated Maxsorb-III. Further, the biomass-derived activated carbon requires the lowest amount of adsorbent per unit mass of combustion fuel in the biomass heating unit. The present thermodynamic analysis is a precursor for optimization of the potential heat-exchanger geometries and operating parameters, with the high-performance carbon adsorbents. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is the mineral nutrient required in greater quantities by plants with deficiencies affecting crop production. Nitrate (NO3-) and ammonium (NH4+) are the inorganic N forms most readily available for plant uptake. We investigated the influence of ammonium and nitrate rates on growth, nutritional status, chlorophyll production, and nutritional efficiency in mahogany seedlings, grown in an Oxisol soil under greenhouse conditions. Treatments were five N rates (50, 100, 150, 200, and 400 mg dm−3 N) in ammonium and nitrate forms and control treatment (0 mg dm−3 N), in a factorial design with five replications. The plants were harvested for evaluation at 150 days after transplanting. N supply affected mahogany growth, mainly in the production of leaf tissue. The maximum economic efficiency of N rates for production of leaf tissue was around 190 mg dm−3 N. The ammonium supply enhanced leaf tissue production, with a 20% increase in leaf area and 15% in leaf dry matter compared to nitrate. Furthermore, the plants showed a preference for ammonium uptake in rates above 200 mg dm−3 N, which indicates that the preference for N form was dependent on the concentration of N in the soil. The ammonium supply enhanced nutritional status, mainly phosphorus, demonstrating high synergism on uptake of this nutrient. Conversely, a strong antagonism between nitrate and phosphorus uptake was observed. Thus, ammonium enhanced the growth and nutritional status of mahogany seedlings and must be prioritized in its fertilization. [ABSTRACT FROM AUTHOR]

Efficient cashew plants in relation to nutrition may represent gains in growth and production, especially in low fertility soils. This study aimed to determine the accumulation, the uptake, transport, and utilization efficiencies in different cashew genotypes. Twelve genotypes were evaluated, 10 of the dwarf type, a common type, and a hybrid. The seedlings were grown in plastic pots filled out with organic substrate. Sixty days after sowing, the plants were collected for the determination of dry matter and macro and micronutrients concentrations. Nutrient accumulation in cashew follows the descending order: N > K > P > Mg > Ca > S > Fe > Mn > Cu > B > Zn. Overall, for all nutrients, plants from BRS 274 had the high accumulation and utilization efficiency; the CCP 06 and CCP 76 in uptake; and the CCP 76 and BRS 189 in transport. [ABSTRACT FROM AUTHOR]

Permanent raised-bed is an alternative planting system for wheat (Triticum aestivum L.) in rain-fed areas. However, this system in monoculture conditions produces lower yields compared with wheat in rotation. Our objective was to estimate these yield differences as affected by nitrogen (N) use efficiency (NUE). Wheat in monoculture and in rotation with maize (Zea maysL.) was evaluated for eight years (2002–2009) with four N rates (0, 40, 80 or 120 kg ha−1). Yield response to N in monoculture was consistently lower than for wheat in rotation. Yield reduction in monoculture at low and high N rate was 81 and 99% attributed to NUE out of which 70 and 82% was due to the uptake efficiency (UPE) and 30 and 19% to the utilization efficiency (UTE), respectively. Total N uptake proved to be the parameter that needs to be improved to enhance wheat yield in monoculture. Abbreviations:NUE: nitrogen use efficiency; UPE: uptake efficiency; UTE: utilization efficiency; Ns: nitrogen supply; NDVI: normalized difference vegetation index [ABSTRACT FROM PUBLISHER]

The aim of this work was to compare Cr(III) and Cr(VI) removal kinetics from water by Pistia stratiotes and Salvinia herzogii. The accumulation in plant tissues and the effects of both Cr forms on plant growth were also evaluated. Plants were exposed to 2 and 6 mg L−1of Cr(III) or Cr(VI) during 30 days. At the end of the experiment, Cr(VI) removal percentages were significantly lower than those obtained for Cr(III) for both macrophytes. Cr(III) removal kinetics involved a fast and a slow component. The fast component was primarily responsible for Cr(III) removal while Cr(VI) removal kinetics involved only a slow process. Cr accumulated principally in the roots. In the Cr(VI) treatments a higher translocation from roots to aerial parts than in Cr(III) treatments was observed. Both macrophytes demonstrated a high ability to remove Cr(III) but not Cr(VI). Cr(III) inhibited the growth at the highest studied concentration of both macrophytes while Cr(VI) caused senescence. These results have important implications in the use of constructed wetlands for secondary industrial wastewater treatment. Common primary treatments of effluents containing Cr(VI) consists in its reduction to Cr(III). Cr(III) concentrations in these effluents are normally below the highest studied concentrations in this work. [ABSTRACT FROM PUBLISHER]

The effects of different concentrations of P and N, added separately or combined, on the Cr(III) accumulation capacity ofP. stratioteswere studied.Plants and pond water with the addition of contaminant(s) were placed in plastic aquaria. Cr concentration was 5 mg L–1, while P and N concentrations were 5 mg L–1or 10 mg L–1. Nutrient addition significantly favoured Cr removal and enhanced Cr translocation to leaves. In Cr treatments a high detritus formation from loss of root biomass was observed probably due to its toxicity. Cr was mainly accumulated in the detrital fraction, whereas P and N were retained fundamentally in leaves. A toxic effect was observed in the Cr + P10 and Cr + N10 treatments. These results could be applied to enhance Cr removal efficiency of constructed wetlands using P. stratiotes, where nutrient enrichment could be attained by treating sewage together with the industrial effluents. [ABSTRACT FROM AUTHOR]

Faba bean (Vicia faba L.) is one of the most important food legumes grown in Morocco under rainfed conditions. This crop requires phosphorus (P) fertilizers to produce higher yields. However, many farmers use low quantities of P because of its cost and the risk of drought. Consequently, the use of varieties with high P use efficiency (PUE) can improve productivity and farmers' income under erratic conditions where the application of high amounts of P is not economically justified. The genetic variation of PUE among Moroccan faba bean varieties was studied under different levels of available phosphorus to orientate the choice of adapted varieties. Two experiments were conducted, under rainfed conditions, at the experiment station of Douyet (Morroco) in 2000–2001 (year 1) and 2002–2003 (year 2). In both years, four P treatments 0, 40, 80 and 120 kg P2O5 ha−1 as fertilizer and four faba bean varieties (G) were tested. In year 1, the varieties tested were Aguadulce, Defès, Karabiga and Lobab. The same varieties were used in year 2 with the exception of Aguadulce, which was replaced by a determinate genotype with smaller straw production. Results showed that the G effect on PUE was significant in year 1, but not in year 2. In the conditions of the moderate P availability (year 1), the variety Defes had the highest PUE and grain yield. Where P availability was lower (year 2), the highest PUE was reached by Karabiga; however, the difference with Defes was not significant. Data showed also that PUE was positively correlated with harvest index (HI) and phosphorus harvest index (PHI). In year 1, genotypic variation for PUE was mainly explained by phosphorus utilization efficiency; but not by phosphorus uptake efficiency. From this study, we can conclude that for rainfed conditions, the breeding strategy is to develop genotypes like Defes with high HI and improved PUE. [ABSTRACT FROM PUBLISHER]

This study compares the nitrogen (N) use efficiency of safflower and sunflower in pot experiments, as the putatively high nitrogen use efficiency of the former is not sustained. Safflower out-yielded sunflower at low N supply, while at ample supply the opposite was observed. Both species accumulated similar amounts of N per pot at equivalent N supplies, but safflower was a better N accumulator due to lower dry matter production. Safflower utilizes absorbed N more efficiently than sunflower to produce seed yield at suboptimal N supply in terms of efficiency ratio and utilization index, but the opposite holds true at optimal and high supply. Functional analysis of utilization efficiency for dry matter and seed production substantiated the higher efficiency of safflower. It is concluded that in terms of N utilization safflower represents a low input crop and outperforms sunflower with respect to seed yield on soils low in available N. [ABSTRACT FROM AUTHOR]