Nitrogen fixation by a subclover-grass mixture grown on two acid soils treated with lime

1993 ◽  
Vol 44 (4) ◽  
pp. 863 ◽  
Author(s):  
JHA Butler

The effect of liming on symbiotic N2 fixation by subclover (Trifolium subteraneum) grown with ryegrass (Lolium multiflorum) was measured under glasshouse conditions using the 15N dilution technique. Two acid soils, a sand and a loam, were treated with two rates of lime or left unamended. In general, lime addition to both soils increased total dry matter yields, but in the loam, grass made up most of the increase, whereas in the sand, subclover made up all of the increase in dry matter. N2 fixation in both untreated soils was negligible. Lime addition increased the percentage N in the total herbage, had little effect on the proportion (Patm) and amount of N fixed by subclover grown on the loam, but dramatically increased both Pat, and the amount of N fixed by subclover growing in the sand. Subclover grown in the loam was poorly nodulated, despite the addition of large amounts of nodulaid (rhizobium survival in the soil was not a factor), but was well nodulated in the sand, thus explaining the lack of fixation in the loam. Higher amounts of inorganic N produced in the loam shortly after germination have the potential to inhibit nodulation in this soil. Also the loam, after liming but before planting, contained higher amounts of nitrate-N and total inorganic N than the sand, and the total inorganic N mineralized by the loam (518 versus 347 mg per pot by harvest) would also have had some effect on N2 fixation had nodulation taken place at a later date. Levels of critical nutrients (B, Ca, Cu, K, Mg, Mo and P) were measured in the clover tops, but no element appeared to be in deficit or excess, except A1 which could not be excluded as being at a toxic level in the limed loam in the present trial.

1979 ◽  
Vol 71 (3) ◽  
pp. 461-465 ◽  
Author(s):  
J. W. Friedrich ◽  
L. E. Schrader ◽  
E. V. Nordheim
Keyword(s):  

1999 ◽  
Vol 26 (8) ◽  
pp. 737 ◽  
Author(s):  
Marcus Schortemeyer ◽  
Owen K. Atkin ◽  
Nola McFarlane ◽  
John R. Evans

The interactive effects of nitrate supply and atmospheric CO2 concentration on growth, N2 fixation, dry matter and nitrogen partitioning in the leguminous tree Acacia melanoxylon R.Br. were studied. Seedlings were grown hydroponically in controlled-environment cabinets for 5 weeks at seven 15N-labelled nitrate levels, ranging from 3 to 6400 mmol m–3. Plants were exposed to ambient (~350 µmol mol–1) or elevated (~700 µmol mol–1) atmospheric CO2 for 6 weeks. Total plant dry mass increased strongly with nitrate supply. The proportion of nitrogen derived from air decreased with increasing nitrate supply. Plants grown under either ambient or elevated CO2 fixed the same amount of nitrogen per unit nodule dry mass (16.6 mmol N per g nodule dry mass) regardless of the nitrogen treatment. CO2 concentration had no effect on the relative contribution of N2 fixation to the nitrogen yield of plants. Plants grown with ≥50 mmol m–3 N and elevated CO2 had approximately twice the dry mass of those grown with ambient CO2 after 42 days. The rates of net CO2 assimilation under growth conditions were higher per unit leaf area for plants grown under elevated CO2. Elevated CO2 also decreased specific foliage area, due to an increase in foliage thickness and density. Dry matter partitioning between plant organs was affected by ontogeny and nitrogen status of the plants, but not by CO2 concentration. In contrast, plants grown under elevated CO2 partitioned more of their nitrogen to roots. This could be attributed to reduced nitrogen concentrations in foliage grown under elevated CO2.


1999 ◽  
Vol 79 (2) ◽  
pp. 277-286 ◽  
Author(s):  
P. A. Bowen ◽  
B. J. Zebarth ◽  
P. M. A. Toivonen

The effects of six rates of N fertilization (0, 125, 250, 375, 500 and 625 kg N ha−1) on the dynamics of N utilization relative to extractable inorganic N in the soil profile were determined for broccoli in three growing seasons. The amount of pre-existing extractable inorganic N in the soil was lowest for the spring planting, followed by the early-summer then late-summer plantings. During the first 2 wk after transplanting, plant dry-matter (DM) and N accumulation rates were low, and because of the mineralization of soil organic N the extractable soil inorganic N increased over that added as fertilizer, especially in the top 30 cm. From 4 wk after transplanting until harvest, DM and N accumulation in the plants was rapid and corresponded to a rapid depletion of extractable inorganic N from the soil. At high N-fertilization rates, leaf and stem DM and N accumulations at harvest were similar among the three plantings. However, the rates of accumulation in the two summer plantings were higher before and lower after inflorescence initiation than those in the spring planting. Under N treatments of 0 and 125 kg ha−1, total N in leaf tissue and the rate of leaf DM accumulation decreased while inflorescences developed. There was little extractable inorganic soil-N during inflorescence development in plots receiving no N fertilizer, yet inflorescence dry weights and N contents were ≥50 and ≥30%, respectively, of the maxima achieved with N fertilization. These results indicate that substantial N is translocated from leaves to support broccoli inflorescence growth under conditions of low soil-N availability. Key words: N translocation, N fertilizer


1970 ◽  
Vol 37 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ilknur Akgun ◽  
Metin Tosun ◽  
Suleyman Sengul

Prior {Lolium perenne × Festuca pratensis) and Elmet (Lolium multiflorum × Festuca pratensis) cultivars were compared with Festuca pratensis Huds. and Lolium multiflorum Lam. genotypes for some agronomical characteristics (green and dry matter yields, crude protein, seed yield, crude ash content) under Erzurum ecological conditions. Analysis of variance and mean separation were performed using the SPSS 11.0 computer program. There was a significant difference among genotypes in every character tested except for green and dry matter yield and crude ash content. Hybrid genotypes had higher plant height, dry and green matter yield, seed yield per plant and crude protein yield except 1000-seed weight. Elmet performed better than Prior except for seed yield per plant.   Key words: Festulolium, Lolium, Festuca, Yield, Crude protein, Crude ash doi:10.3329/bjb.v37i1.1556 Bangladesh J. Bot. 37(1): 1-6, 2008 (June)


2012 ◽  
Vol 47 (6) ◽  
pp. 863-868 ◽  
Author(s):  
Marcolino Frederico Miguel ◽  
Henrique Mendonça Nunes Ribeiro Filho ◽  
Steben Crestani ◽  
Fabiana da Rocha Ramos ◽  
Tereza Cristina Moraes Genro

The objective of this work was to assess the effects of the sward structure of Italian ryegrass (Lolium multiflorum), during the first grazing cycle, on its morphological and bromatological characteristics throughout the growing season, and on the performance of dairy cows. The treatments consisted of two structures obtained as a function of canopy-light interception: high-light interception (HLI) and low-light interception (LLI), with different pre-grazing heights in the first grazing cycle. Pasture was managed under rotational grazing with a herbage allowance not below 30 kg dry matter (DM) per cow per day. Three grazing cycles, with a grazing interval of 30 days, were evaluated. Pre-grazing herbage mass was greater (2,240 vs. 1,656 kg ha-1 DM), but the proportion of leaf blades was smaller (0.35 vs. 0.43) for HLI swards. Neutral detergent fiber (NDF) content and organic matter digestibility (OMD) were similar between treatments in the first grazing cycle, but in the second and third ones NDF was greater, and OMD lower, for the HLI swards. Milk yields were greater for cows grazing LLI swards (19.4 vs. 21.1 kg per day). Initial grazing with 90% of light interception promotes greater nutritional value in the subsequent cycles.


1993 ◽  
Vol 120 (3) ◽  
pp. 361-369 ◽  
Author(s):  
C. A. Watson ◽  
S. M. Fowlerf ◽  
D. Wilman

SUMMARYOn two organic farms, nitrate-N and ammonium-N in the surface layers of the soil of representative fields were recorded for 2 years. Nitrate-N was also determined in different soil layers down to 120 cm at the beginning, middle and end of two winters and at intervals after ploughing three fields, to seek evidence of leaching.Nitrate-N and ammonium-N were both consistently low in the surface layers of fields in ley. Nitrate-N accumulated in arable soils on some occasions when there was little or no crop uptake of N, after ploughing, and after very heavy applications of manure.There was some evidence of nitrate leaching in all five fields which were deep-sampled. In four cases, the loss by leaching appeared to be < 25 kg N/ha per winter. In the other case, in which a 4-year ley was ploughed on 5 October, the loss by leaching appeared to be c. 70 kg N/ha. Ploughing in winter, rather than early autumn, might have reduced the nitrate leached, but the drilling of the next crop might have been delayed.The nitrate concentration of water draining from recently ploughed sandy soil in Shropshire was high, but it would have been diluted by water draining from unploughed fields.


2000 ◽  
Vol 80 (4) ◽  
pp. 849-860 ◽  
Author(s):  
D. M. Dean ◽  
B. J. Zebarth ◽  
C. G. Kowalenko ◽  
J. W. Paul ◽  
K. Chipperfield

This study examined the effects of solid poultry layer manure addition on soil N processes and on dry matter and N accumulation in red raspberry (Rubus idaeus L.). In trials conducted in two years, approximately 50% of the 400 kg total N ha−1 applied as manure was recovered as soil inorganic N 1 mo after manure application when manure was incorporated within 4 h of application. Three trials were conducted in two commercial raspberry fields: one with no history of manure use and one other with a history of heavy annual applications of poultry manure. Treatments included 55 kg N ha−1 as NH4NO3, 100 or 200 kg total N ha−1 as manure, and a control that received no manure or fertilizer N. Soil inorganic N to 60 cm depth was measured throughout the growing season. Berry yield was estimated, and dry matter and N accumulation was determined in floricanes at first berry ripening and in primocanes at the end of the growing season. Few significant effects of N fertilization were measured for any crop yield, growth or N accumulation parameter. This was attributed to the large (>150 kg N ha−1) supply of N to the crop in the unamended soil, primarily from soil N mineralization. Dry matter accumulation in the fruiting clusters was strongly correlated to estimated berry yield, and may provide a simple means for assessing relative yield within experiments. Soil nitrate measured in August after berry harvest may serve as a "report card" to assess N management in the current growing season, to refine fertilizer N management for subsequent growing seasons, and as an index of the risk of nitrate leaching over the following fall and winter in south coastal British Columbia. Key words: Nitrogen mineralization, nitrate leaching, manure N availability, Rubus idaeus


1962 ◽  
Vol 13 (5) ◽  
pp. 853 ◽  
Author(s):  
GW Lanigan ◽  
VR Catchpoole

Laboratory silages made from pure crops of three varieties of ryegrass (Lolium multiflorum, Lolium perenne, and Lolium sp., N.Z. H1 strain) differed according to maturity at harvest. When ensiled at a stage of development characterized by first appearance of heads, all varieties tested sustained an initial lactic fermentation which ensured an adequate degree of stability during prolonged storage. Earlier harvesting tended to give less satisfactory results. Species effects, if present, could not be distinguished from possible effects of seasonal factors in this investigation. Experiments conducted with known mixtures of short rotation ryegrass (N.Z. HI strain) and white clover (Trifolium repens) showed that the proportion of the legume which could be added without appreciable ill-effect increased with later harvesting. Major adverse effects of clover additions appeared as increased losses of dry matter in the effluent and a greater tendency to instability in the silage, the latter being demonstrated by destruction of part of the lactic acid accumulated earlier, with consequent rise in pH level during storage.


1995 ◽  
Vol 46 (7) ◽  
pp. 1401 ◽  
Author(s):  
RR Gault ◽  
MB Peoples ◽  
GL Turner ◽  
DM Lilley ◽  
J Brockwell ◽  
...  

Nodulation, N2 fixation (estimated by 15N natural abundance methods) and dry matter production were studied in a lucerne (Medicago sativa) crop managed for hay production at Ginninderra Experiment Station, A.C .T. Measurements were taken in the year of establishment and during two subsequent growing seasons. There were three treatments: (1) no inoculation and no annual fertilizer applied, (2) initial inoculation and superphosphate applied annually, (3) no inoculation, superphosphate applied annually and ammonium sulfate periodically. Before planting and after each growth season, soil was analysed for extractable mineral nitrogen, total nitrogen and the 15N natural abundance of this nitrogen, to the depth explored by lucerne roots. Before planting, no appropriate root-nodule bacteria (Rhizobium meliloti) were detected in the soil and initially plants were nodulated only in the inoculated treatment. Thereafter nodulation increased on the other treatments. Eight months after sowing there were no differences between treatments in numbers of R. meliloti g-l soil or in nodulation. In the third growing season, almost 30 kg ha-1 (dry wt) of nodules were recovered to a depth of 25 cm. These nodules were primarily located on fine, ephemeral roots and many appeared to be renewed after cutting of the lucerne. In the year of establishment, dry matter yields (0% moisture) totalled 3 to 4 t ha-1 in three hay cuts. In succeeding years, total yields were in the range 10 to 13 t ha-1 in four or five cuts per season. Nitrogen removed in the harvested lucerne reached 340 to 410 kg N ha-lyr-l in the second and third years and between 65 and 96% of this N arose from N2 fixation, depending on the method of calculation used. Poorer dry matter production and N2 fixation in treatment 1 in the third growing season was attributed to an insufficient supply of available phosphorus. Fixed N removed in Lucerne hay from treatment 2 totalled at least 640 kg N ha-1 in the three years of the experiment. Also, there were substantial increases in soil nitrogen due to lucerne growth. Although soil compaction made the quantification difficult, at the end of the experiment it was estimated that there was at least an extra 800 kg N ha-1 in the total soil nitrogen under lucerne compared to strips of Phalaris aquatica grown between the lucerne plots. It was concluded that lucerne contributed at least the same amount of fixed nitrogen to the soil as was being removed in the harvested hay.


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