Effects of Nitrogen Fertilization on Monoterpenes of Jack Pine Seedlings and Weight Gain of Jack Pine Budworm (Lepidoptera: Tortricidae)

Nine-month old jack pine (Pinus banksiana) seedlings were grown in a greenhouse under four nitrogen fertilization regimes. Levels of total nitrogen and five monoterpenes in new foliage were measured. Fertilization resulted in four significantly different levels of foliar nitrogen; means ranged from 1.8-4.5 percent dry weight. Contrary to predictions of resource availability theory, seedlings grown under the highest fertilization regime had higher foliar monoterpene levels than seedlings in the other treatments. Newly molted, sixth-instar female jack pine budworm (Choristoneura pinus pinus [Lepidoptera: Tortricidae]) larvae were allowed to feed for four days on new foliage of the seedlings. Larvae that fed on low-nitrogen seedling gained less weight and process more vegetation than did larvae on high- nitrogen seedlings. Larval weight gain was positively related to foliar nitrogen

The economic impact of future biological nitrogen fixation technologies

The economic impact of some future biological nitrogen fixation technologies are estimated using AGSIM, a dynamic, partial equilibrium, econometric model of the U.S. agricultural sector. Five separate scenarios were modeled: (1) legumes fix more nitrogen, (2) legumes fix more nitrogen with an increase in legumes yields of 10 percent, (3) nitrogen fertilization requirements on all crops are reduced 50 percent with no yield changes, (4) total elimination of nitrogen fertilization and (5) total elimination of nitrogen fertilization and non-legume yields decrease 10 percent. Results indicate that biological nitrogen fixation technologies have a high value to society. Increasing the efficiency of legumes to fix nitrogen may have an annual benefit of $1,067 million while decreasing nitrogen fertilization by 1,706 thousand tons. Total elimination of nitrogen fertilization of the crops has an annual benefit of$4,484 million.Crop Production/Industries,

Nitrogen balances in Dutch organic greenhouse production

The organic greenhouse production in the Netherlands is limited with regard to the number of growers, but plays an important role in EU organic greenhouse production. In the high-technology greenhouses a high production level is realized but nitrogen balances of this production system have been questioned. In order to document and improve the nitrogen balance, the production of seven greenhouses was monitored and soils were repeatedly analysed. The model “Bemestingsrichtlijn biologische kasteelten” (Fertilization Guide Organic Greenhouse Production) has been developed to simulate nitrogen availability and to fine-tune manure applications to crop demand. In the course of four years the overall nitrogen surpluses decreased sharply, but due to the observational character of the research no statistical analyses can be made. Part of the high surpluses in the first years can be explained by initial investments in soil organic matter. Calculation of the dynamic balance gives more possibilities to fine-tune farmers’ fertilization strategies. Growers that followed the model-based advise for manure application, realized a substantial reduction of nitrogen surpluses

The Effect of Nitrogen Fertilization and Water Stress on Stomatal Aperture, Chlorophyll Content and Proline Accumulation of Napier Grass (Pennisetum Purpureum Schum)

The objective of the study was to determine the effect of nitrogen fertilization and water stress on the stomatal aperture, chlorophyll and proline accumulation of Napier grass (Pennisetum purpureum Schum.) The effect of water stress and nitrogen fertilizer levels were evaluated within an arrangement of Completely Randomized Design with factorial pattern (2x3). The variables observed were stomatal aperture, total chlorophyll and proline content. The results showed interaction between water stress and the level of fertilization. Interaction between water stress with nitrogen fertilization showed that the stomatal openings were more narrow (P0.05) with increasing levels of nitrogen fertilization either with sufficient water or with water stress. The exception is treatment of enough water and fertilizer 250 kg N/ha (P<0.05) where stomatal aperture decreased compared with no fertilizer. The total chlorophyll content of both the sufficiently watered and the water stressed Napier grass on nitrogen fertilizer rose with increasing doses of nitrogen fertilizer. The conditioning of water stress with fertilizer dose of 0 kg N/ha and 150 kg N/ha did not increase the total chlorophyll, however a dose of 250 kg N/ha resulted in an increase of total chlorophyll (P<0.05). Interaction between water stress and nitrogen fertilizer levels showed that the content of proline rose (P<0.05) with increasing levels of nitrogen fertilization, as well as with water stress treatment (P<0.05). It is concluded that water stress on Napier grass plants lowers stomatal aperture width, but increases proline accumulation and nitrogen fertilizer increases total chlorophyll and proline accumulation. There was an interaction between nitrogen fertilizer with water stress

Einfluss von Einstrahlungsintensität, Stickstoffangebot, Düngungsverfahren und Hornkieselapplikation auf den Nitrat-, Ascorbinsäure- und Glucosinolatgehalt bei Salatrauke (Eruca sativa)

Effects of nitrogen supply (high / low), fertilizer type (biodynamic / organic / mineral) and application of the biodynamic horn silica preparation on nitrate, ascorbic acid and glucosinolate contents of rocket (Eruca sativa L.) were studied under conditions of full sunlight (100% photosynthetically active radiation PAR) and shading (55% PAR). Nitrate contents increased in response to shading and under conditions of full sunlight also in response to high nitrogen supply and mineral fertilization. Ascorbic acid contents were significantly higher with low nitrogen supply, biodynamic and organic fertilization, horn silica application and under conditions of low nitrogen supply with full sunlight. Glucosinolate contents were significantly increased by low nitrogen supply, full sunlight (in combination with biodynamic fertilization) as well as biodynamic and organic fertilization (under conditions of full sunlight)

Abatement costs for agricultural nitrogen and phosphorus loads: a case study of South-Western Finland

Designing efficient agri-environmental policies for agricultural nutrient load reductions calls for information on the costs of emission reduction measures. This study develops an empirical framework for estimating abatement costs for nutrient loading from agricultural land. Nitrogen abatement costs and the phosphorus load reductions associated with nitrogen abatement are derived for crop farming in southern Finland. The model is used to evaluate the effect of the Common Agricultural Policy reform currently underway on nutrient abatement costs. Results indicate that an efficiency designed policy aimed at a 50 % reducton in agricultural nitrogen load would cost 25 to 28 million euro, or 1995 to 2197 euro per farm

Proximate controls on semiarid soil greenhouse gas fluxes across 3&nbsp;million years of soil development

Soils are important sources and sinks of three greenhouse gases (GHGs): carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). However, it is unknown whether semiarid landscapes are important contributors to global fluxes of these gases, partly because our mechanistic understanding of soil GHG fluxes is largely derived from more humid ecosystems. We designed this study with the objective of identifying the important soil physical and biogeochemical controls on soil GHG fluxes in semiarid soils by observing seasonal changes in soil GHG fluxes across a three million year substrate age gradient in northern Arizona. We also manipulated soil nitrogen (N) and phosphorus availability with 7&nbsp;years of fertilization and used regression tree analysis to identify drivers of unfertilized and fertilized soil GHG fluxes. Similar to humid ecosystems, soil N2O flux was correlated with changes in N and water availability and soil CO2 efflux was correlated with changes in water availability and temperature. Soil CH4 uptake was greatest in relatively colder and wetter soils. While fertilization had few direct effects on soil CH4 flux, soil nitrate was an important predictor of soil CH4 uptake in unfertilized soils and soil ammonium was an important predictor of soil CH4 uptake in fertilized soil. Like in humid ecosystems, N gas loss via nitrification or denitrification appears to increase with increases in N and water availability during ecosystem development. Our results suggest that, with some exceptions, the drivers of soil GHG fluxes in semiarid ecosystems are often similar to those observed in more humid ecosystems

N USE AND PARTITIONING IN CORIANDER (CORIANDRUM SATIVUM L.) AFTER ORGANIC AND CONVENTIONAL N FERTILIZATION

In coriander, a well known spice herb, many studies concerning the effect of N fertilization have been conducted in special areas where the cultivation of such plant has a major importance, such as India. Limited information is available as concerns the response of coriander to N fertilization under Mediterranean climatic conditions, above all when organic N fertilizers (mandatory when organic cropping management is chosen) are used. This work refers about some observations realised from 2004 to 2006 by an experiment on organic and mineral N fertilization techniques in coriander, carried on in the experimental farm “Sparacia” (Cammarata, AG, Sicily). Similarly to what suggested for other species, each year at harvest time, for each fertilizer treatment, seeds yield and plant biomass were weighed and the respective N content was determined in order to compare N plant uptake with total and mineral N measured in the soil before and after cropping cycle. From such data a few indices were calculated in order to get information about the efficiency of use by plants of the tested N forms. Some differences in N partitioning and use efficiency according to treatment were noticed, suggesting an overall higher efficiency of N chemical fertilizers

The Effects of Nitrogen Fertilization and Deficit Irrigation Practices on Tomato Growth and Chlorophyll Concentration

Irrigation and fertilization are absolutely necessary in order to increase productivity in agricultural production. Water is the most important source of life on the earth. All living things need absolute water so that they can continue plants life. The fact that the nutrients present in the soil can complete the natural cycle is completely dependent on the water cycle. Irrigation is the amount and time required for the root zone of the plant in soil, which is needed by the plant and cannot enough by precipitation in agriculture. This study was carried out in the farmer\u27s greenhouse conditions between 2004-2005 years. Three different doses of nitrogen (N1:75 ppm N, N2:150 ppm N, N3:225 ppm N) were applied to the tomato plant grown in the greenhouse. S1:100% full irrigation, S2:50% irrigation according to pot capacity. The study was based on a trial randomized block design with 3 replications. At the end of 2 years, the results gave us; the best plant growth was measured with N3S1 an average height by128 cm. The worst plant height was obtained from N1S2 an average height by 88 cm. Plant body diameter has been found between 0,82cm and 0,54cm. Irrigation practices were more effective to total chlorophyll content than the fertilization practices. As a result, the deficit irrigation has also developed as well as full irrigation. Deficit irrigation and nitrogen fertilizer increased crop yield in arid regions.It is suggested that irrigation water can be reduced and adequate fertilization can be increased crop production in arid regions