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The West Asia-North Africa region, which is characterized by a typical Mediterranean climate, is the center of origin of cereals, notably wheat (Triticum spp.) and barley (Hordeum spp). However, cereal production, which is primarily rainfed, is mainly constrained by drought due to the low rainfall accompanied by high temperatures. Cereals have been tradi-tionally grown following a fallow period in order to achieve acceptable yields on stored soil moisture, but they are increasingly grown either continuously or in rotation with legumes, either food or forage. Barley is grown throughout the Mediterranean region, generally in the drier zones and often on shallow soils and with application of minimum or no fertilizers. The medium-rainfall zone of central Morocco (200-500 mm yr-1) is typical of the region as a whole. In order to provide a rational basis for barley fertilization, especially as regards ni-trogen (N), a field trial was established near Settat, involving five barley varieties (ACSAD-60, Tessaout, Asni, Arig-8, and ACSAD-176), along with four N application at four levels (0, 40, 80, and 120 kg N ha-1), grown on a shallow soil (Petrocalcic Palexeroll) for two growing seasons that varied in terms of total rainfall (Year 1, 261mm and Year 2, 302 mm) as well as within-season distribution. There were considerable differences between crop years, with significantly higher yields in the second growing season when rainfall was heavy at the criti-cal tillering and stem-elongation growth stages. Nitrogen consistently increased dry matter and grain yields in either year, generally being significant up to 80 kg ha-1. There were sig-nificant differences observed among varieties, as well as interactions of varieties with years. The six-row variety Arig-8 was consistently the best while the two-row Asni, the lowest yielding variety. Where an economic analysis was done on yield data (Year 1), N fertilization up to at least 80 kg ha-1 was considered as profitable. Crop N uptake varied with varieties and increased with increasing fertilizer. N Recovery was variable and generally less than 50%. In contrast to many other fertilizer trials with barley in the region, this trial from cen-tral Morocco showed highly significant yield increases in response to applied N for barley varieties, most of which performed similarly. Therefore, N fertilization of barley in Mo-rocco’s semi-arid cereal-producing zone on shallow soils, where root growth and moisture-holding capacity are limited, should be promoted.

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This study was conducted to determine the effects of different water and nitrogen application levels on drip-irrigated tomato plants. The amount of water usage was based upon the pan evaporation from a screened (class “A”) evaporation pan. The treatments consisted of two irrigation intervals (I1= 5 days and I2= 10 days), three plant-pan coefficients (Kcp1= 0.50; Kcp2= 0.75 and Kcp3= 1.00) and three nitrogen (N) levels (N0 = 0, N1= 80 and N2= 160 kg ha-1). The I, Kcp and N levels affected the tomato yields and water usage efficiencies, however the effects of nitrogen applications were found to be greater than those of the other applications. Consequently, to reach the maximum tomato yields under similar climate and soil conditions, plant-pan coefficients (Kcp) and nitrogen values should be equivalent to 1.00 and 160 kg ha-1, respectively.

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 Reducing nitrogen status of floriculture plants is an effective tactic in pest management by decreasing host plant quality. Life table parameters and population growth rate of Aphis craccivora(Hemiptera: Aphidiae), as well as cosmetic and qualitative parameters losses associated with aphid infestation were evaluated in relation to N fertilization levels on Gomphrena globosa, under greenhouse condition. Four N fertilization levels (0, 30, 60, and 100% of recommended 2 kg m^-3) were used. The results indicated that aphid’s intrinsic rate of natural increase on plants fertilized with 100% of the recommended N level was the highest. Abundance and population growth rate of aphid also positively correlated with N fertilization levels. The interactive effect of aphid population and N fertility significantly affected growth parameters of the plants. In the absence of aphid, plant yield improved linearly with increasing N levels. However, aphid population highly decreased shoot to root ratio and the number of flowers in plants fertilized with 100% of the recommended N level. According to our findings, fine-tuning fertility to reduce A. craccivora population is a steadfast tactic to produce marketable globe amaranth ornamental plant.

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This study was conducted in 2014-2015 to determine the effects of nitrogen (N) fertilization on yield, quality traits, and storage ability of two tomato cultivars, namely, ‘Calista’, for processing, and ‘Volna’, for fresh market. N was applied in doses of 0, 50, 100, and 200 kg N·ha^-1. Significant interactions were found between the studied years, N fertilization, and cultivars. Both tested cultivars produced high and similar yields in the year with good growing conditions during vegetation period. In the year with unfavorable weather conditions (lower average temperature, more total rainfall, and a smaller sum of GDD), cv. ‘Volna’ produced a significantly lower yield compared to the cv. ‘Calista’. N fertilization had a significant impact on yield, however, the reaction of cultivars varied in each years. In 2014, quadratic positive regression was found between N rates and yield of cv. ‘Calista’ (R²=0.90) and linear relation for cv. ‘Volna’ (R²=0.77). In 2015, however a linear positive regression was found for cv. Volna (R²=0.71) and cv. Calista (R²= 0.44). The chemical and physical parameters of tomato quality varied depending on the year of cultivation. On average for the studied years and cultivar, increasing N fertilization affected the lycopene and soluble polyphenols content, as well as total flavonoids and ascorbic acid content and antiradical activity. N rate did not affect dry matter and soluble solids content, fruit firmness, fruit redness, and acidity. Cultivar ‘Calista’ had significantly higher lycopene content and better fruit firmness than cv. ‘Volna’ for fresh market. Furthermore, the storage ability of tomatoes cv. ‘Calista’ was significantly better than cv. ‘Volna’.