The influence of two soil nitrogen levels on the utilisation of15N-labelled ammonium nitrate by ryegrass

1986 ◽  
Vol 37 (5) ◽  
pp. 454-460 ◽  
Author(s):  
R. James Stevens ◽  
Harry I. Gracey ◽  
Ronald J. Laughlin ◽  
Hubert J. Logan
1988 ◽  
Vol 68 (1) ◽  
pp. 63-75 ◽  
Author(s):  
LEONARD J. EATON ◽  
DAVID G. PATRIQUIN

Soil ammonium and nitrate in the top 15 cm of soil were monitored after application of ammonium nitrate and ammonium sulfate to plots at 14 PF (previously fertilized) and 12 NF (never fertilized) lowbush blueberry (Vaccinium angustifolium Ait.) stands representing a range of soil types and management histories. Overall, nitrate values in unfertilized and ammonium sulfate plots were higher at PF than at NF sites, suggesting greater nitrification at PF sites. In laboratory incubation studies, nitrification proceeded immediately in soil from a PF site, but only after a 4-wk lag in that from an adjacent NF site. Nitrification rates were low compared to that in a garden soil (pH 6.6). N-Serve inhibited nitrification in both soils. In ammonium nitrate plots, "excess" N values (N values in fertilized plots minus values in unfertilized plots) were higher for PF than for NF sites, suggesting greater immobilization, plant uptake or loss of N at NF sites. There was no evidence, in laboratory studies, of immobilization of added N by soil from either type of site. Rhizome N concentration increased significantly in response to fertilization at an NF site, but not at a PF site. Key words: Blueberry (lowbush), fertilizer and soil nitrogen


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 844
Author(s):  
Carlos Martín Sastre ◽  
Ruth Barro ◽  
Yolanda González-Arechavala ◽  
Ana Santos-Montes ◽  
Pilar Ciria

Nitrogen fertilizers have been identified in energy crops LCAs as the main contributors to global warming, as well as to many other environmental impacts. The distinct production process and application emissions of nitrogen fertilizer types for top dressing produce different GHG savings when energy crops value chains are compared to fossil energy alternatives. In this study, three types of fertilizers (calcium ammonium nitrate, urea and ammonium sulphate) at N top dressing rates of 80 kg N/ha are used to grow rye for electricity generation under the conditions of the Continental Mediterranean climate of central-northern Spain. Complete LCAs for the whole value chain based on real data were performed in conjunction with soil nitrogen balances (SNBs) to assess the accomplishment of European Union (EU) GHG savings sustainability criteria, as well as the sustainability of fertilization practices for soil nitrogen stocks. The results obtained can provide interesting insights for policy making, since calcium ammonium nitrate, the most common fertilizer for rye crops, led to 66% GHG savings, as opposed to the 69% achieved when applying urea and 77% when ammonium sulphate was used. Nevertheless, the three fertilizers produced annual soil deficits greater than 50 kg N/ha. In order to ensure savings above 80%, as required by the EU sustainability criteria, and sustainable SNBs, additional optimization measures should be taken at key points of the value chain.


2005 ◽  
Vol 45 (4) ◽  
pp. 459 ◽  
Author(s):  
M. Ashraf ◽  
Q. Ali ◽  
E. S. Rha

Growth and nutrient accumulation in Kalonji (Nigella sativa L.) under varying levels of nitrogen, were examined in a field experiment. Sixty-three-day-old plants were supplied with varying levels of nitrogen of 0, 30, 60 and 90 kg N/ha soil. Maximum biomass and seed yield were recorded at 30 and 60 kg N/ha. The soil nitrogen level, 90 kg/ha, proved to be ineffective in promoting growth of Kalonji. Accumulation of nitrogen, potassium and phosphorus in both shoots and roots of Kalonj increased consistently with increase in soil nitrogen. However, this pattern of increase in the levels of 3 nutrients in plant tissues had a negative association with the growth of the crop, particularly at the supra-optimal nitrogen levels (60 and 90 kg N/ha).


Botany ◽  
2011 ◽  
Vol 89 (4) ◽  
pp. 255-261 ◽  
Author(s):  
Corinthe Zekveld ◽  
John Markham

Plants can respond to herbivore damage by mounting a resistance response or by compensating for lost fitness. Both plant nutrition and interactions with soil microbes can affect these responses. It has been shown that resistance responses can occur before plants have been attacked by herbivores. Here we show that a tolerance type of response can occur when plants are exposed to, but not fed on by, herbivores. Alnus viridis (Chaix) DC. spp. crispa (Ait.) Turrill were grown in sealed containers under positive air pressure with either 0.5 mmol·L–1 or 2.0 mmol·L–1 nitrate and either inoculated or not inoculated with Frankia , their nitrogen-fixing symbiont. Plants were then exposed to the genus-specific aphid Prociphilus tessallatus Fitch, which failed to establish feeding colonies. Exposure to aphids, formation of nitrogen-fixing nodules, and elevated soil nitrogen levels all significantly increased plant yield with no interaction among these factors. A combination of high soil nitrogen, nodulation, and exposure to aphids resulted in the lowest plant root:shoot ratio. Plants that were grown with low nitrogen and were exposed to aphids showed increased nitrogen-fixing activity within a day of being exposed. These results provide further evidence to support the observation that plants can respond to cues from other organisms prior to receiving herbivore damage.


1982 ◽  
Vol 8 (3) ◽  
pp. 179-186 ◽  
Author(s):  
Oyebiodun G. Longe ◽  
B.L. Fetuga ◽  
M.E. Aken'ova

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