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More sustainable practices involving biological nitrogen fixation (BNF) and the use of portable chlorophyll meter in fertilization management are promising to increase nitrogen (N) use efficiency in the common bean crop. This study aimed to monitor N managements using a portable chlorophyll meter and its effects on agronomic attributes of Carioca-type common bean cultivars with indeterminate and determinate growth habits (‘IPR Campos Gerais’ and ‘IAC Imperador’). The experiment was carried out in a randomized block design (RBD), in a 2 × 9 factorial scheme, with four replicates. The first factor consisted of the cultivars and the second factor of the N management. The data were subjected to analysis of variance by F test and, when necessary, the means were grouped by the Scott-Knott test at 5% probability level. The use of portable chlorophyll meter is a viable alternative for N monitoring and management in common bean, allowing the reduction of top-dressing N application, regardless of the cultivar used. Highlights The use of portable chlorophyll meter is a viable alternative for nitrogen monitoring and management in common bean. Management with chlorophyll meter reduced the need for chemical fertilizer application, saving 105 kg ha-1 of urea. Further studies are needed to better understand this technology under conditions with different genotypes, soils and production systems.

More sustainable practices involving biological nitrogen fixation (BNF) and the use of portable chlorophyll meter in fertilization management are promising to increase nitrogen (N) use efficiency in the common bean crop. This study aimed to monitor N managements using a portable chlorophyll meter and its effects on agronomic attributes of Carioca-type common bean cultivars with indeterminate and determinate growth habits ('IPR Campos Gerais' and 'IAC Imperador'). The experiment was carried out in a randomized block design (RBD), in a 2 × 9 factorial scheme, with four replicates. The first factor consisted of the cultivars and the second factor of the N management. The data were subjected to analysis of variance by F test and, when necessary, the means were grouped by the Scott-Knott test at 5% probability level. The use of portable chlorophyll meter is a viable alternative for N monitoring and management in common bean, allowing the reduction of top-dressing N application, regardless of the cultivar used. [ABSTRACT FROM AUTHOR]

Wheat is an important staple crop in arid and semi-arid areas of the Tigray region of Ethiopia. However, the yield and quality of the crop is markedly constrained by low soil fertility, inappropriate rate and timing of nitrogen application. Therefore, an experiment was conducted to elucidate the effect of different rates and timing of nitrogen fertilizer application on the yield, quality, and nitrogen use efficiency of bread wheat varieties during 2013 and 2014 main cropping seasons. The treatments consisted of four rates of nitrogen (23, 46, 69, and 92 kg N ha-1), three timing of N application (½ at sowing + ½ at tillering, ¼ at sowing + ½ at tillering + ¼ at anthesis, and 1/3rd at sowing + 1/3 rd at tillering + 1/3rd at anthesis) and two bread wheat varieties (Picaflor and Mekelle I) and 0 kg N ha-1 (control). The experiment was laid out as a randomized complete block design in a factorial arrangement with three replications. During both cropping years, increasing the rate of nitrogen application up to 69 kg N ha-1 significantly (P< 0.01) increased the total aboveground biomass and grain yields of the crop and decreased with further increase of applied N fertilizer. The highest aboveground biomass (6871 kg ha-1) and grain yields (2775 kg ha-1) of the crop were obtained in response to the application of 69 kg N ha-1, in 2013. The equivalent value for total aboveground biomass and grain yields during 2014 cropping season were (8815 kg ha-1and 3695 kg ha-1), respectively . The highest apparent recovery efficiency of 75% was obtained in response to the rate of 69 kg N ha-1applied in three splits of 1/4 at planting, ½ at tillering, and 1/4 at anthesis. The equivalent values for the highest apparent recovery was 81% in the 2014 cropping season. The highest agronomic efficiency of 25 kg kg-1 and utilization efficiency of 55 kg kg-1 were recorded at the rate of 46 kg N ha-1 in three splits of 1/4 at planting, ½ at tillering and ¼ at anthesis. The equivalent values in 2014 were 34 kg kg-1 and 78 kg kg-1, respectively. Grain protein concentration increased from 10.57% to 11.82% in 2013 and from 8.97% to 9.84% in 2014 cropping season as the rate increased from 23 kg N ha-1 to 69 kg N ha-1. The acceptable marginal rate of return (1618%) and highest net benefit (34141ETB ha-1) was obtained from 69 kg N ha-1 for the variety Picaflor. In conclusion, applying 69 kg N ha-1 in three splits of ¼ at planting, 1/2 at tillering and ¼ at anthesis resulted in optimum grain yield, protein concentration and economic return of the crop.

Abstract: The objective of this work was to evaluate the effects of closing cut dates (CCD) and nitrogen (N) rates on the components of pure seed yield (PSY) and seed quality in 'Mombasa' grass (Megathyrsus maximus 'Mombaça'), besides determining the parameters of apparent N efficiency (ANE) and agronomic N efficiency (AgNE). The field experiments were carried out over two growing seasons, 2010/2011 and 2011/2012, in Umuarama, PR, Brazil. The folllowing treatments were evaluated: CCD on October 10, January 31, February 15, and March 1; and N doses at 0, 75, 150, and 225 kg ha-1. Significant interactions between the CCD and N doses were observed for the panicle tiller number (PTN), pure seeds per panicle, PSY, ANE and AgNE. Values of ANE and AgNE were better for 150 kg N ha-1. There were no effects of CCD and N doses on seed quality. PSY was closely correlated with PTN, pure seeds per panicle, and pure seed number.The CCD treatments of longer growth duration and higher N doses showed the higher PSY. Final CCD delaying until February and N availability reduced yield. Closing cut date and N fertilization affect pure seed yield and yield component responses of 'Mombasa' grass.

Field experiments were conducted to determine the effect of nitrogen (N) fertilizer forms and doses on wheat (Triticum aestivum L.) on three soils differing in their ammonium (NH4) fixation capacity [high = 161 mg fixed NH4-N kg−1 soil, medium = 31.5 mg fixed NH4-N kg−1 soil and no = nearly no fixed NH4-N kg−1 soil]. On high NH4+ fixing soil, 80 kg N ha−1 Urea+ ammonium nitrate [NH4NO3] or 240 kg N ha−1 ammonium sulfate [(NH4)2SO4]+(NH4)2SO4, was required to obtain the maximum yield. Urea + NH4NO3 generally showed the highest significance in respect to the agronomic efficiency of N fertilizers. In the non NH4+ fixing soil, 80 kg N ha−1 urea+NH4NO3 was enough to obtain high grain yield. The agronomic efficiency of N fertilizers was generally higher in the non NH4+ fixing soil than in the others. Grain protein was highly affected by NH4+ fixation capacities and N doses. Harvest index was affected by the NH4+ fixation capacity at the 1% significance level. [ABSTRACT FROM AUTHOR]

Pot marigold seeds contain oil with a specific composition (presence of calendic acid); hence, they can be used as an alternative oil raw material. In 2011–2013, a field experiment was conducted to determine the effect of different nitrogen doses (0, 30, 60, 90, 120, 150 kg N∙ha-1) on the seed yield, oil content, and fatty acid composition in four pot marigold cultivars. Nitrogen fertilization exerted a positive effect on the number of flower heads and seed yield. However, the response of marigold cultivars to nitrogen doses applied varied, i.e. the yield of the ‘Tokaj’ and ‘Radio’ cultivars was significantly increased up to the dose of 60 kg N∙ha-1, whereas such an increase was noted in the ‘Orange King’ and ‘Persimmon Beauty’ cultivars at the dose of 90 kg N∙ha-1. Nitrogen fertilization modified the content of fat: the low nitrogen doses (30 kg N∙ha-1) did not influence the fat content in the seeds, whereas the increasing doses resulted in its gradual decline. The cultivars were characterised by significant differences in plant morphology, seed yield, and fat quality. During the three-year period, the highest seed and fat yields were determined for the ‘Orange King’ cultivar (1857.3 and 339.3 kg·ha-1, respectively) and the highest proportion of calendic acid in the oil (54.86%) was detected in the ‘Persimmon Beauty’ cultivar. The yield and quality of marigold oil depended on both nitrogen fertilization and the weather conditions prevailing during the growing seasons. The increase in the nitrogen doses was accompanied by an increase in the content of linoleic acid and a decrease in the level of oleic acid. The cooler and wetter growing season in 2011 turned out to promote the highest fat and calendic acid accumulation.

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Pot experiments were conducted on three soils differing in their ammonium (NH4+) fixation capacity [high = 161 mg NH4-nitrogen (N) kg-1 soil; medium = 31.5 mg NH4-N kg-1 soil; and no = no NH4-N was additionally fixed], and the effect of N fertilizer forms and doses on wheat (Triticum aestivum L.) was investigated. Grain yields responded to almost all forms of N fertilizer with 80, 160, and 240 kg N ha-1 in the high, medium, and no NH4+ fixing soil process, respectively. Agronomic efficiency of applied N fertilizers was significantly greater in the no NH4+ fixing soil. Thousand grain weights (TGW) of wheat grown on the high and medium NH4+ fixing soil decreased with increasing N. Grain protein increased with increasing NH4+ fixation capacity. Nitrogen doses and the forms of N fertilizers affected grain protein at a significance level. The combination of urea + ammonium nitrate (NH4NO3) was most effective in increasing grain protein content. [ABSTRACT FROM AUTHOR]