Increasing Nitrogen Fertilization Research Articles

Effects of nitrogen fertilization rate on tocopherols, tocotrienols and γ-oryzanol contents and enzymatic antioxidant activities in rice grains.

Tocopherols (Toc), tocotrienols (T3) and γ-oryzanol (GO), major bioactive compounds of rice, are known to possess potent antioxidant activity. In this study, the objective was to determine the effects of nitrogen fertilization rate on contents of Toc, T3 and GO, and activities of enzymatic antioxidants in rice grains. Experiments were conducted on five different levels of nitrogen fertilization. Among the different treatments, grains of 2N (two-fold of the recommended amount of nitrogen fertilizer) treatment showed the highest total Toc, total T3, α-T3, β-Toc, γ-Toc and γ-T3 levels, whereas 0N (no treatment) group had the highest GO content. Increasing nitrogen fertilization significantly reduced the rice grain catalase and ascorbate peroxidase, but not the superoxide dismutase activities. Under 0N and 0.5N (low N fertilization) treatments, malondialdehyde and H2O2 contents in rice grains were significantly higher than that of other treatments. These results suggest that a two-fold increase in nitrogen fertilization favor the accumulation of Toc and T3 but not GO in rice grains.

Deep soils modify environmental consequences of increased nitrogen fertilizer use in intensifying Amazon agriculture

Agricultural intensification offers potential to grow more food while reducing the conversion of native ecosystems to croplands. However, intensification also risks environmental degradation through emissions of the greenhouse gas nitrous oxide (N2O) and nitrate leaching to ground and surface waters. Intensively-managed croplands and nitrogen (N) fertilizer use are expanding rapidly in tropical regions. We quantified fertilizer responses of maize yield, N2O emissions, and N leaching in an Amazon soybean-maize double-cropping system on deep, highly-weathered soils in Mato Grosso, Brazil. Application of N fertilizer above 80 kg N ha−1 yr−1 increased maize yield and N2O emissions only slightly. Unlike experiences in temperate regions, leached nitrate accumulated in deep soils with increased fertilizer and conversion to cropping at N fertilization rates >80 kg N ha−1, which exceeded maize demand. This raises new questions about the capacity of tropical agricultural soils to store nitrogen, which may determine when and how much nitrogen impacts surface waters.

Effect of Preceding Crop, Rates and Splitting of Nitrogen Fertilizer on Bread Wheat Production and Nitrogen Use Efficiency

A field experiment was conducted at the Agronomy Department Farm, Faculty of Agriculture, Assiut University during 2015/2016 and 2016/2017 seasons to study the effect of preceding crop, rates and splitting of nitrogen fertilizer on bread wheat production and nitrogen use efficiency. The experiment was carried out in randomization complete block design (RCBD) using split-split plot arrangement with three replications. Cropping system (corn-clover-wheat and corn-fallow-wheat) were assigned in main-plots while nitrogen fertilizer rates (56.25, 75.00 and 93.75 kg N/fed) were allotted in sub-plots and splitting doses of nitrogen (two, three and four equal doses) were allocated in sub-sub plots. The obtained data showed that plant height, spike length, number of spikes/m2, number of grains/spike, weight of grains/spike, seed index, grain yield, straw yield and nitrogen use efficiency were significantly affected by cropping sequence in favor of planting wheat after clover (fahl berseem) in the two growing seasons except nitrogen use efficiency in the first season. Increasing nitrogen fertilizer rates resulted in significant increase in all previous traits except nitrogen use efficiency trait which was decreased by increasing nitrogen fertilizer rates in both seasons. Moreover, splitting nitrogen rates into four equal doses significantly increased all studied traits as compared to three or two equal splits in the two growing seasons. Also, all interactions had a significant effect on all studied traits in both seasons. The highest mean values of grain yield (27.47 and 28.22 ard/fed in the first and second seasons, respectively) were obtained from the sequence of corn-clover-wheat when received highest nitrogen rate (93.75 kg N/fed) which was applied at four equal doses.

RESPONES OF TWO GARLIC (Allium sativum L.) VARITIES TO DIFFERENT LEVLES OF NITROGENOUS FERTILIZERS AND SOIL APPLICATION OF TWO TYPES OF HUMIC ACID FERTILIZERS

This study was conducted at experiment Farm of Horticulture and Landscape Design Dep. / College of Agriculture and Forestry / Mosul University during the growing season 2012-2013 to investigate the effects of three levels of nitrogen fertilizers at rate: zero, 100 and 150 Kg N / ha. The second factor included adding two types of organic fertilizer (humic acid): Matrex 15at 2 ml/ l. and Fitohum at 2 gm/ l. and control treatment, in order to study their effects on the vegetative growth, quantity and quality of the yield of two garlic varieties (Chinese and local). The result showed that local variety was significantly superior in head circumference and bulbs fresh weight per plant at second stage (220 days after planting), cloves and circumferences number per head Whereas, Chinese variety was significantly superior than local variety in leaves number per plant at two growing stages (167 and 220 days after planting).The vegetative growth and quantitative and qualitative characters of the yield i.e. leaves number, head circumference and bulbs fresh weight per plant at second stages (220 days after planting), cloves and circumferences number per head, mean weight of clove, total and marketable yield increased by increasing nitrogen fertilization levels. Whereas, the fertilized plants with 150 Kg N/ha. were significantly more superior than non-fertilized and fertilized plants in the previous mentioned characters. Whereas, plants fertilized with organic fertilizer Fitohum were significantly superior than non-fertilized plants and fertilized plants with organic fertilizer Matrex 15 in head circumference, bulbs fresh weight per plant (at two growing stages) and total and marketable yield. The result indicted that local variety plants that fertilized with nitrogen fertilizer at level 150 Kg N/ha and organic fertilizer Fitohum gave the highest values of total yield and marketable yield 10.998 and 10.992 ton / ha. for previous traits respectively.

Effects of Organic and Conventional Crop Nutrition on Profiles of Polar Metabolites in Grain of Wheat.

The profiles of polar metabolites were determined in wholemeal flours of grain from the Broadbalk wheat experiment and from plants grown under organic and low-input systems to study the effects of nutrition on composition. The Broadbalk samples showed increased amino acids, acetate, and choline and decreased fructose and succinate with increasing nitrogen fertilization. Samples receiving farm yard manure had similar grain nitrogen to those receiving 96 kg of N/ha but had higher contents of amino acids, sugars, and organic acids. A comparison of the profiles of grain from organic and low-input systems showed only partial separation, with clear effects of climate and agronomy. However, supervised multivariate analysis showed that the low-input samples had higher contents of many amino acids, raffinose, glucose, organic acids, and choline and lower sucrose, fructose, and glycine. Consequently, although differences between organic and conventional grain occur, these cannot be used to confirm sample identity.

English

Irish potatoes are an important crop only promoted in cool and high moist conditions of Rwanda. This study explored the productivity of Irish potatoes varieties under increasing nitrogen fertilizer applications in drier agro-climatic conditions of the eastern Rwanda. Potato seeds mass-selected from locally-grown varieties in the region surrounding Kibungo town (-2.160897°, 30.543591°) were planted under rain-fed conditions, during the March to June agricultural season of 2015, in the three experimental farms of the University of Kibungo at Karenge, Mugesera and Rwamagana, respectively located in Kibungo town, 30 km West and 50 km North of Kibungo town. The most performing three varieties were tested again in 2016A season (October to January, 2016) at Kibungo and Rwamagana. For each season, and at each farm, four nitrogen application rates (0, 60, 120, and 180 kg N ha-1) were tested. Phosphate and potash were supplied in sufficient amounts of 150 kg P2O5 ha-1 and 60 kg K20 ha-1, respectively. No fertilizers were applied on the control treatment. A split plot design and three replicates were used with varieties in main plots and nitrogen in sub-plots. Plant growth rate, shoot counts, tuber calibration, and total and market potato tuber yields were monitored. Four varieties yielded 10 tons ha-1 or more of total potato tuber yields in 2015B season. Three of them, namely Kirundo, Gasore, and Peko varieties, were re-tested in 2016. Over the two seasons, Kirundo variety stood out with 12.8 and 10.5 tons ha-1 of total and marketable tuber yields, respectively. All the varieties significantly responded to nitrogen fertilizer. However, Kirundo variety, respectively yielded 22 tons and 17 tons ha-1 of total and market potato tuber yields under 120 kg N ha-1 during the 2016A season. Irish potato can therefore be grown and produce substantial yield in eastern Rwanda, provided that appropriate nitrogen fertilization and seed quality are available. Key words: Irish potatoes, varieties, nitrogen, yields, fertilizer, rates.

Nitrogen source contribution in sugarcane-inoculated plants with diazotrophic bacterias under urea-N fertigation management

Although Brazilian sugarcane crops use lower nitrogen rates when compared to other producing countries, the biological nitrogen fixation (BFN) could be performed aiming to reduce costs, since almost all nitrogen fertilization used in Brazil is imported. BFN can occur in sugarcane; however, its role in non-leguminous plants is controversial. Therefore, this study aimed to assess the nitrogen source contribution (using N isotope 15N technique) along a growing period in sugarcane plants under different management (diazotrophic bacteria inoculation and N fertigation rates). The natural abundance of nitrogen isotope (15N) abundance in + 1 leaves of fourth ratoon cultivar SP 80-3280 was used to indicate the comparative importance of N sources, including BFN for sugarcane nutrition. The treatments were irrigated with two levels of nitrogen fertilizer 50 and 100 kg ha−1 (urea source), including a control without fertilizer, with (I) and without (NI) inoculation of nitrogen-fixing bacterias. The bacteria cocktail used consisted of five strains: Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae, H. rubrisubalbicans, Burkholderia tropica and Azospirillum amazonense. Although the nitrogen content in + 1 leaves, the above ground dry matter, cane yield and stalk sugar content expanded by increasing nitrogen fertilizer rates, no significant interactions between nitrogen-fixing bacteria inoculation and nitrogen fertilizer rates were observed. In the treatment without N fertilizer application, no differences in δ15N‰ (per thousand) values between sugarcane-inoculated and sugarcane-non-inoculated sugarcane leaves was found. The temporal variation of δ15N‰ in sugarcane + 1 leaves indicated that nitrogen content and δ15N‰ values decreased during the phenological development stages and that the main sources of nitrogen for sugarcane were from synthetic fertilizer and mineralization of nitrogen from soil organic matter.

Effect of Sowing Dates and Nitrogen on Productivity of Quinoa (Chenopodium quinoa Willd.) at Desert Areas

Two field experiments were carried out in the Desert Research Center (D.R.C.), Agricultural Experiment Station at EL-Kharga Oasis, New Valley Governorate (27°47.7 42 N, 30°24.7 63 E) during the two growing seasons of 2015/ 2016 and 2016/ 2017 to study the effect of sowing dates and rates of nitrogen fertilizer on productivity and quality of quinoa. Results showed that the effect of sowing dates on all studied parameters was significant except, number of inflorescence/ plant, carbohydrates % and oil % don’t affect significantly by sowing dates during the two growing seasons. Sowing date in 1st December had the highest values for all studied traits as compared with the rest dates during the two growing seasons. There were significant increases in values of studied parameters with increasing nitrogen fertilizer rate up to 150 Kg N fed.-1but without significant in number of inflorescence/ plant and saponin % during both seasons. The interaction between different sowing dates and nitrogen fertilizer levels had a significant effect on yield and quality of quinoa except, number of inflorescence/ plant and saponin % which did not any significant by the interaction between sowing dates and nitrogen fertilizer during the two growing seasons. Cultivation of quinoa on 1st December and fertilization by150 kg N fad-1 gave maximum values of studying parameters during the two growing seasons at the desert area under NewValley conditions.

The impact of barley nitrogen fertilization rate on barley brewing using a commercial enzyme (Ondea Pro)

Two Australian (Buloke and Commander) and two Canadian (CDC Meredith and Bentley) barley varieties were grown under four levels of nitrogen fertilization (0, 20, 40 and 80 kg ha−1). Barley samples were assessed by barley brewing with the Ondea Pro enzyme cocktail for mashing analysis and were compared with typical malt brewing quality specifications. The study observed that increased nitrogen fertilization resulted in increased barley kernel nitrogen content which significantly impacted a range of wort quality parameters including increased soluble nitrogen, free amino nitrogen and barley beta‐amylase level, but also reduced extract, barley Kolbach index, β‐glucan and colour. Increased grain nitrogen had relatively little effect on apparent attenuation limit, lautering and barley limit dextrinase level. Knowledge of the effects of interactions between barley of different qualities (e.g. nitrogen content) and the Ondea Pro enzymes on wort quality will result in enhanced barley to directly and efficiently brew good quality beer, to better satisfy the quality expectations of brewers.

Producing Compliant Polluters: Seed Companies and Nitrogen Fertilizer Application in U.S. Corn Agriculture

AbstractThe majority of research to date has attributed the pollution problems associated with agriculture to the independent decisions of individual farmers; in this article, we illustrate how seed companies' subtle forms of coercion encourage farmers to become compliant polluters. We focus on corn farmers in the midwestern United States, whose management decisions have become increasingly controlled by seed companies. Beyond obvious forms of control, seed companies influence farmers in ways that are less apparent. Drawing from Foucault's concept of disciplinary power, we explore how seed companies have encouraged farmers to increase their application of nitrogen fertilizer through disciplinary mechanisms that naturalize the imposition of constraints. We argue that seed companies employ disciplinary techniques related to the biology of the seed, the product life cycle, and knowledge. While most farmers believe their fertilizer decisions are made independently, these disciplinary techniques compel farmers to increase nitrogen fertilizer application, resulting in increased water pollution and greenhouse gas emissions.

Effect of population density and nitrogen fertilizer levels on growth, yield components, yield, and fiber properties of Egyptian cotton (Giza 95)

Two field experiments were carried out at the Farm of Sids Research Station, BaniSwef Governorate, Agricultural Research Center, Egypt, during the two successive seasons of 2016 and 2017. The aim of this study was to investigate the effect of three population density through five plant distribution, i.e. 64615 plants/fed from 10 cm between hills with leaving single plant/hill (A), 64615 plants/fed from 20 cm between hills with leaving double plants/hill (B), 43076 plants/fed from 15 cm between hills with leaving single plant/hill (c), 43076 plants/fed from 30 cm between hills with leaving double plants/hill (D) and 51692 plants/fed from 25 cm between hills with leaving double plants/hill (E) under four nitrogen fertilizer levels, i.e. (30, 45, 60 and 75 Kg N/fed) on growth, flowering, yield components and yield as well as fiber quality properties for the Egyptian cotton (Gossypium barbadense, L.), variety Giza 95. Significant differences were detected for allmost growth, flowers, yield components and yield as well as fiber properties of cotton among the three plant densities through five plant distributions or four nitrogen fertilizer levels during 2016 and 2017 seasons. Planting pattern of D significantly surpassed the other plant densities and distributions and gave the greatest values in No. of sympodia/plant, No. of fruiting sites/plant, No. of open bolls/plant, boll weight, seed index, seed cotton yield/plant, upper half mean length and uniformity index % as well as significantly gave the shortest period from planting to first flower appearance and lowest values of plant losses % at harvest. Meanwhile, planting pattern of E significantly gave the highest values of seed and lint cotton yields/fed. On the other hand, the greatest values of plant height, No. of days to first flower appearance, lint % and plant losses % were obtained from planting pattern of A. While, planting pattern of B gave the lowest values of micronaire reading. While, the maximum values of strength (g/tex) was recorded from planting pattern of C. plant height, No. of sympodia/plant, No. of days to first flower appearance, No. of fruiting sites/plant, No. of open bolls/plant, boll weight, seed index, seed cotton yield/plant, seed cotton yield/fed, lint cotton yield/fed and uniformity index % showed significantly increased by increasing nitrogen fertilizer levels from 30 up to 75 kg N/fad, except lint % and micronaire reading were significantly decreased in the both seasons. Results revealed that planting pattern of D under soil fertilized by 75 kg N/fed gave the maximum values of No. of sympodia/plant, No. of fruiting sites/plant, No. of open bolls/plant, boll weight and seed cotton yield/plant. While, planting pattern of E with the same level of nitrogen produced the maximum values of seed and lint cotton yields/fed. Meanwhile, the greatest values of plant height and the longest period from planting to first flower appearance were obtained from planting pattern of A when received 75 kg N/fed during both growing seasons. It could be summarized that planting cotton plants (Giza 95) under planting patterns of D or E with soil fertilized by 75 kg N/fad to maximized quantity and quality of cotton yield characters.

Multi-model projections of future climate and climate change impacts uncertainty assessment for cotton production in Pakistan

Future climate projections and impact assessments are critical in evaluating the potential impacts of climate change and climate variability on crop production. Climate change impact assessment in combination with crop, climate models under different climate change scenarios is uncertain and it is challenging to select an appropriate climate scenario. This study quantifies the uncertainty associated with projected climate change impacts on cotton yield in Punjab, Pakistan using 29 general circulation models (GCMs) under high and moderate representative concentration pathway (RCP) scenarios (4.5 and 8.5) at near-term (2010–2039) and mid-century (2040–2069) time spans. Cropping System Model (CSM) CROPGRO-Cotton (DSSAT v 4.6) was calibrated and evaluated with field experiment data collected under arid/semi-arid climatic conditions. Enormous variation was observed in GCMs climatic variables, which were therefore classified into different categories. According to mean ensemble of 29 GCMs, there is a projected increase in seasonal average temperature 1.52 °C and 2.60 °C in RCP 4.5 and 1.57 °C and 3.37 °C in RCP 8.5 scenario as compared to the seasonal baseline (31.48 °C) in near-term (2010–2039) and mid-century (2040–2069), respectively. Maximum consensus by GCMs revealed the increase in temperature of 1.2–1.8 °C and 2.2 to 3.1 °C in RCP 4.5 scenario while 1.4–2.2 °C and 3.0–3.9 °C increase is expected under RCP 8.5 for near term and mid-century time periods, respectively. Similarly, rainfall changes are expected −8% to 15% and −5 to 17% in RCP 4.5 scenario while −8 to 22% and −2 to 20% change is expected under RCP 8.5 scenario in near term and mid-century time periods, respectively. Seed cotton yield (SCY) are projected to decrease by 8% on average by 2039 and 20% by 2069under the RCP 4.5 scenario relative to the baseline (1980–2010). Mean seed cotton yield is projected to decrease by 12% and 30% on average under the RCP 8.5 scenario. Uncertainties were observed in GCMs projections and RCPs due to variations in climatic variables projections. GCMs, GFDL-ESM2M (45% and 35%), GFDL-ESM2G (28% and 43%) and MIROC-ESM (39% and 70%) predicted the higher mean SCY reduction ensemble of cultivars than others under emission scenario of 4.5 in near term and mid-century, respectively. Lower SCY reduction was revealed in CCSM4, HADGEM2-CC, HADGEM2-ES, INMCM4 and CNRM-CM5 due to mild behavior of climatic variables especially temperature under RCP 4.5 in the near-term and mid-century. High reduction in mean SCY (16%–19%) is expected in CMCC-CMS, IPSL-CM5B-LR, GISS-E2-H, GFDL-ESM2M and GFDL-ESM2G under the RCP 8.5 scenario. However, under the same scenario, mean SCY increases by 1% in HADGEM2-ES and by 4% in HADGEM2-CC relative to the baseline yield (4147 kg ha−1). GFDL-ESM2M and GFDL-ESM2G are hot and dry while HADGEM2-ES and HADGEM2-CC are hot but wet, resulting in less cotton yield loss. MIROC-ESM and GFDL-ESM2G projected a severe reduction in mean SCY (70% and 69%) due to a steep increase in maximum and minimum temperature (6.97 °C and 4.38 °C, 4.91 °C and 3.70 °C), respectively and sever reduction in rainfall by mid-century and may call worse case scenarios. Climate models like, CCSM4, HadGEM2-CC, HadGEM2-ES, INMCM4, CanESM2, CNRM-CM5, ACCESS1-0, BNU-ESM and MIROC5 are found less uncertain and showed stable behavior. Therefore, these models can be used for climate change impact assessment for other crops in the region. Adaptation management options like five weeks early sowing than current (10-May), increasing nitrogen fertilization (30%), higher planting density (18% for spreading and 30% for erect type cultivars) and 17% enhanced genetic potential of cultivars would compensate the negative impacts of climate change on cotton crop. This study provide valuable understandings and direction for cotton management options under climate change scenarios. This multi-model and multi-scenario analysis provides a first overview of projected changes in temperature and precipitation, cotton yield and potential management options under changing climate scenarios in arid to semi-arid climatic conditions of Punjab-Pakistan.

EFFECT OF IRRIGATION INTERVALS AND NITROGEN FERTILIZER RATES ON FLAX YIELD AND SOME ANATOMICAL MANIFESTATIONS

Two field experiments were carried out at Gemmeiza Research Station, El-Gharbia Governorate, Agricultural Research Center, Egypt, during the two successive winter seasons of 2015/2016 and 2016/2017. The objective of this work was to evaluate the effect of irrigation intervals (every 21, 28 and 35 days) and nitrogen fertilizers rates [untreated (0), 30, 45 and 60 kg N/fad] on quantity and quality of straw and seed characters of flax (Cultivar Giza 10), in addition to study anatomical manifestation in middle technical stem length. The experimental design was split-plot in three replications. Significant differences were detected for all studied traits, i.e. total plant height (cm), technical stem length (cm), upper branching zone length (cm), straw yield/plant (g), straw yield (kg/fad), total fiber percentage (%), fiber yield (kg/fad), fiber length (cm), number of capsules/plant, number of seeds/capsule, seed index (g),seed yield/plant (g), seed yield (kg/fad), biological yield (kg/fad), oil percentage (%) oil yield (kg/fad)and fiber fineness (Nm)among irrigation intervals or nitrogen fertilizer rates in the combined analysis. Irrigated flax plants every 21 days gave the maximum values for total plant height (cm), technical stem length (cm), upper branching zone length (cm), straw yield/plant (g), straw yield (kg/fad), total fiber percentage (%), fiber yield (kg/fad), fiber length (cm), number of capsules/plant, number of seeds/capsule, seed index (g), seed yield/plant (g), seed yield (kg/fad), biological yield (kg/fad), oil percentage (%) and oil yield (kg/fad) in the combined analysis. On the other hand, significantly gave the low values of fiber fineness (Nm). In contrast, irrigation every 35 days gave the minimum values for all studied characters under this study except, fiber fineness (Nm). Irrigated flax every 28 days gain intermediate estimates in all studied traits without significance with irrigation every 21days. Anatomical studies, i.e. total cross section area (mm2), cortex area (mm2), fiber area (mm2), xylem area (mm2) and pith area (mm2), fiber index (cm3), cortex % and fiber % were increased when irrigated flax plants every 21 days. But xylem % and pith % were decreased. All traits of flax under study showed significantly increased by increasing nitrogen fertilizer rates from untreated up to 60 kg N/fad, except fiber fineness (Nm) was significant decreased with increasing nitrogen rates in the combined analysis. Results reported that no significant differences between soil fertilized by 45 and 60 kg N/fad on all flax traits under study. All anatomical studies, i.e., (total cross section area (mm2), cortex area (mm2), fiber area (mm2), xylem (mm2), pith (mm2), fiber index (mm3), cortex %, fiber % and xylem %) were increased with increasing nitrogen fertilizer rates up to 60 kg N/fad, expect pith % was decreased. Results showed that irrigated flax plants every 21 days and soil fertilized by 60 kg N/fad significantly gave the maximum values of seed, biological and oil yield (kg/fad) in the combined analysis. In addition to great reduction in fiber fineness (Nm) had happened in this case. It could be concluded that planting flax plants (Giza 10) under irrigated interval every 21 or 28 days and soil fertilized by 45 or 60 kg N/fad to maximized quantity and quality of straw and seed yield characters as well as anatomical studies.

Response of Flax Plant to Foliar Spray by Urea and Some of Micronutrients Mixture under Different Nitrogen Levels

Two field trial were conducted at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate, Egypt, during2016/2017 and 2017/2018 winter seasons to study the physiological response of flax (Linum usitatissimum L.) Sakha 3,cultivar to three nitrogen fertilizer rates i.e; 25, 35 and 45 kg N/fad.. in a combination with foliar spray by urea 2(%) plussome of micronutrients mixture of (Fe + Zn + Mn) using concentration at 200 ppm for each element. The maximumvalues of plant height, fruiting zone length, technical length, as well as, leaf area/plant and dry matter accumulation (g)/m2at 80 and 95 days after sowing (DAS), crop growth rate (CGR) and net assimilation rate (NAR) at (80–95 DAS) periodwere obtained when plants received 35 kg N/fad. and foliar spray with urea 2(%)plus 200 ppm micronutrients mixture of(Fe + Zn + Mn). In addition, straw and seed yields, its components, fiber (%), fiber yield, total chlorophyll of leaves at 95DAS, oil (%) and oil yield.The total saturated fatty acids of flax oil were, gradually, increased with increasing nitrogen fertilizer rate from 25 upto 45 kg N/fad., whereas, the total unsaturated fatty acids were decreased. The minimum value of the total unsaturatedfatty acids were obtained from plants received [35 kg N/fad. and a spray with 200 ppm micronutrients mixture of (Fe+ Zn+Mn)].

Effect of Increased Nitrogen Application Rates and Environment on Protein, Oil, Fatty Acids, and Minerals in Sesame (<i>Sesamum indicum</i>) Seed Grown under Mississippi Delta Conditions

Information on the effect of nitrogen fertilizer rates and environment on sesame seed composition and nutrition is scarce. The objective of this research was to investigate the effects of nitrogen fertilizer application rates on sesame seed yield, protein, oil, fatty acids, and mineral nutrition. A two-year (2014, 2015) field experiment was conducted. Nitrogen fertilizer (urea ammonium nitrate) solution (UAN, 32% N) was applied by side dressing to four sesame varieties (S-34, S-35, S-38, S-39) at rates of 44.7, 67.2, 89.6 and 112.0 kg·ha-1. Rate of 44.7 kg·ha-1 was used as control since this rate is traditionally recommended in the region. Increasing nitrogen application rates resulted in higher protein and oleic acid contents in two varieties in 2014, and in all varieties in 2015. Increased protein and oleic acid were accompanied by lower total oil and linoleic acid. Increased nitrogen application also resulted in higher seed N, S, B, Cu, Fe, and Zn in 2014 in S-34 and S-35, but either a decline or no clear change was observed in seed levels of these nutrients in S-38 and S-39. In 2015, increased nitrogen application resulted in significantly higher seed N in all varieties, and higher S, B, Cu, Fe, and Zn in some varieties. A significant positive correlation was observed between nitrogen application rate and yield, and with seed levels of protein, oleic, acid, N, B, Cu, Fe, and Zn. A significant negative correlation was observed between nitrogen application rate and seed oil and linoleic acid. Thus, increased nitrogen fertilizer application resulted in higher seed protein, oleic acid, and some mineral nutrients, but lower oil and linoleic acid. However, this effect depended on variety and environmental conditions. Because higher protein and oleic acid are desirable traits for sesame seed nutritional value and oil stability, regional breeders should select sesame varieties for efficient fertilizer response.

Effects of nitrogen and irrigation water application on yield, water and nitrogen utilization and soil nitrate nitrogen accumulation in summer cotton

A field experiment was carried out to study the effects of nitrogen and irrigation water application on growth, yield, and water and nitrogen use efficiency of summer cotton, and to develop the optimal water and nitrogen management model for suitable yield and less nitrogen loss in summer cotton field in the Huang-Huai region. Two experimental factors were arranged in a split plot design. The main plots were used for arranging nitrogen factor which consisted of five nitrogen fertilizer le-vels(0, 60, 120, 180, 240 kg·hm-2, referred as N0, N1, N2, N3, N4), and the subplots for irrigation factor which consisted of three irrigation quota levels (30, 22.5, 15 mm, referred as I1, I2, I3). There were 15 treatments with three replications. Water was applied with drip irrigation system. Experimental results showed that both irrigation and nitrogen fertilization promoted cotton growth and yield obviously, but nitrogen fertilizer showed more important effects than irrigation and was the main factor of regulating growth and yield of summer cotton in the experimental region. With the increase of nitrogen fertilization rate and irrigation amount, the dry mater accumulation of reproductive organs, the above-ground biomass at the flowering-bolling stage and seed cotton yield increased gradually, reached peak values at nitrogen fertilization rate of 180 kg·hm-2 and decreased slowly with the nitrogen fertilization rate further increased. The maximum yield of 4016 kg·hm-2 was observed in the treatment of N3I1. Increasing nitrogen fertilizer amount would improve significantly total N absorption of shoots and N content of stem and leaf, but decrease nitrogen partial factor productivity. The maximum irrigation-water use efficiency of 5.40 kg·m-3 and field water use efficiency of 1.24 kg·m-3 were found in the treatments of N3I3 and N3I1, respectively. With increasing nitrogen fertilization amount, soil NO3--N content increased and the main soil NO3--N accumulation layer moved downward. By comprehensively considering above-ground biomass, seed cotton yield, water and nitrogen uptake and utilization, and soil NO3--N accumulation in the soil profile, the treatment N3I1 could be recommended as the optimal water and nitrogen application pattern for summer cotton production in the experimental region.

Fast estimation of chlorophyll content on plant leaves using the light sensor of a smartphone

Medir clorofila puede apoyar decisiones de fertilización nitrogenada de plantas. Usando un dispositivo impreso en 3D y un LED rojo, aquí probamos la factibilidad de usar un teléfono celular para estimar clorofila por transmisión de luz. Al comparar 30 lecturas de trasmisión de luz roja (663 nm) por hojas de sorgo Sorghum bicolor (L.) Moench, obtenidas del teléfono y de un espectrómetro estándar, se encontró un buen coeficiente de determinación (r2 = 0.9067). Adicionalmente, se hizo una comparación entre las lecturas del teléfono y un SPAD 502TM (un dispositivo comercial para la estimación del contenido de clorofila) en hojas de crisantemo Dendranthema grandiflora Tzvelev, obteniendo una buena correlación entre ambas medidas. La transmisión medida en hojas de S. bicolor de plantas de invernadero fertilizadas con nitrógeno también presentó buen ajuste con la altura de las plantas, sugiriendo la posibilidad de estimar fácilmente el contenido de clorofila en hojas usando teléfonos inteligentes.

Soil respiration declines with increasing nitrogen fertilization and is not related to productivity in long-term grassland experiments

Soil respiration is often used as an index of fertility because the majority of nutrients are cycled through the microbial biomass. We assessed the role of soil respiration as a measure of resource productivity in three long-term grassland experiments near Pietermaritzburg, South Africa. All of these experiments have shown significant changes in grass species composition and productivity. An ongoing Veld (=field) Fertilizer Experiment (VFE) that manipulated the level of nitrogen fertilizer, phosphorus and lime has been running since 1951. A Burning and Mowing Experiment (BME) has been running since 1950. The third experiment is part of the Nutrient Network (NutNet), a global fertilizer experiment that has been manipulating nitrogen, phosphorus, potassium and micronutrients and has been running since 2009. We found that longer-term experiments were more likely to show significant effects on soil respiration. We found several significant effects in the VFE but no significant differences in soil respiration among fertilization treatments in the shortest-term experiment (NutNet). In the VFE, we found significant differences in soil respiration due to levels of nitrogen fertilizer, form of nitrogen fertilizer (limestone ammonium nitrate and ammonium sulphate), phosphorus and lime. We found no significant relationship between above-ground net primary productivity and soil respiration despite the frequent detection of such a pattern due to the link between soil respiration, soil fertility and productivity. We found that, while there was a consistent increase in total soil nitrogen with increasing levels of nitrogen fertilizer applied, there was a consistent decrease in soil microbial respiration. There was a significant positive correlation between soil respiration and pH. Possible mechanisms behind this are unclear but may involve changes in dominant enzymes and possibly switches between dominance of bacteria and fungi. We also found significant effects of the timing of burning in the BME, but not due to the frequency of burning or the occurrence of mowing. Our results suggest that studies may need to be long-term, for example here at least 10 years, before key functional relationships with soil fertility can be reliably understood.

Long-term tillage and nitrogen fertilization: Consequences for nitrifier density and activity

Nitrification is the biological oxidation of NH3 to NO2− and then NO3−. Understanding soil management consequences for nitrifier ecology could improve nitrogen (N) fertilizer use, decrease NO3− leaching, and minimize NO and N2O emissions. This study examined how long-term N fertilization and tillage influenced nitrifier density, ratios, and nitrification rate. The study site had > 40years of continuous maize (Zea mays L.) with three nitrogen fertilization rates (0, 168, and 336kgha−1) and either no-tillage or plow tillage. The Most Probable Number (MPN) method was used to estimate the cell density of ammonia-oxidizing (AOB) and nitrite-oxidizing (NOB) bacteria and the shaken slurry method was used to measure potential nitrification rates. Tillage, fertilization, and their interaction significantly influenced the ammonia oxidizer and nitrite oxidizer cell densities and the potential nitrification rate. Nitrifier cell densities increased with increased nitrogen fertilization; nitrite oxidizer density increased more than ammonia oxidizer density leading to a decreasing AOB:NOB ratio. There were positive correlations between ammonia oxidizer and nitrite oxidizer cell densities, especial in plow tillage. The trends for nitrifier cell density and potential nitrification rate were not consistent. Fertilization increased ammonia oxidizer and nitrite oxidizer densities and potential nitrification rate, but the influence of tillage differed for different fertilization rates. This long-term field trial demonstrated that specific soil management practices differentially influence not only the cell density of nitrifiers, but their relative ratios and their response to increased inorganic nitrogen in the environment.

Azot i siarka jako czynniki kształtujące plon nasion oraz zawartość i jakość tłuszczu nagietka lekarskiego – potencjalnego surowca olejarskiego

The aim of the study was to evaluate the effect of nitrogen and sulphur fertilization on the seed yield, oil content, and fatty acid composition of calendula. The experiment was set up as a split-block design with two factors: the first factor was the nitrogen dose: 0, 30, 60, 90 and 120 kg N·ha–1, and the second was the sulphur dose: 0, 30 kg S·ha–1. The best effects of the nitrogen fertilization on productivity were achieved with the doses in the range of 60–90 kg N·ha–1. Sulphur showed a favourable effect on the seed yield and fat content (effectiveness of sulphur increased along with the increasing nitrogen fertilization). Nitrogen fertilization modified the fatty acid composition, causing an increase in the percentage of linolenic acids and a reduction of oleic acid contents in oils. Sulphur did not affect the quality of fat. However, this feature was markedly influenced by meteorological conditions prevailing during growth and ripening of plants.