Fertiliser requirements of spring oilseed rape

Because of the increasing importance of oilseed rape in the United Kingdom, 26 field experiments were done on the fertiliser requirements of the spring-sown crop in the years 1973 to 1975. Seed and oil yield were increased by nitrogen in 23 of the 26 experiments, though oil content was reduced somewhat. On average, the crop required 187 kg/ha of N for optimum yield and there was little difference in yield between seedbed and split N applications. Response to P was small on average, varied between years and was not well correlated with soil analysis; a 2 tonne/ha crop removes about 32 kg/ha P₂O₅. Mean response to K was very small and a 2 tonne/ha crop removes about 15 kg/ha K₂O; spring oilseed rape appears to require no applied K, except perhaps on soils of low K status. The crop did not respond at all to application of S.     

Amounts of N,P and K fertilizers needed by maize intended for fodder production in Southern England

Eighteen field trials were carried out from 1973 to 1975 (inclusive) in Southern England to assess the N, P and K requirement of fodder maize on soils with a wide variation in levels of available N, P and K ranging from low to high. It was only slightly (and not consistently) responsive to the added nutrients, though N, P, and K offtake by the crop was large. Practical considerations for formulating a fertilizer policy for this crop are discussed. Under conditions of low fertility, maximum yields of dry matter may be obtained with 60 kg ha^?1 of N and 75 kg ha^?1 of both P₂O₅ and K₂O, but this practice would deplete reserves of P and K in the soil. This should be rectified later in the crop rotation.     

Long‐term impact of nitrogen and potassium fertilizers on yield,soil nutrients and biochemical parameters of tea

A field experiment was conducted with tea cultivar UPASI‐9 over a period of 9 years to evaluate the long‐term effects of nitrogen (N) and potassium (K) fertilizers on yield, biochemical parameters, soil and leaf nutrient status. The yield increase was as high as 66% over the control for N application of 450 kg ha^?1 year^?1. Polyphenol and amino acid contents increased with increase in K application rate. Positive and significant correlation was found between nitrate reductase activity and the amino acid content of the tea shoots. While ammoniacal nitrogen in the soil was not affected by the application of fertilizer, ammonium acetate extractable K increased. The failure to apply fertilizer resulted in depletion of the organic matter status of the soil. Although increased rate of nitrogen application increased the overall yield of made tea (kg ha^?1 year^?1), the specific yield (kg kg^?1 N) declined. The soil tended to become acidic from frequent application of high doses of nitrogenous fertilizer. The leaf NK status was significantly influenced by the various treatments. Copyright © 2004 Society of Chemical Industry     

The response of double-low winter oilseed rape to fertiliser sulphur

The effect of soil-applied ammonium sulphate (10, 20, 30, 50 and 80 kg S ha^?1) and agricultural gypsum (20 and 50 kg S ha^?1) and of foliar-applied elemental sulphur (20 kg S ha^?1) on the seed yield and chemical composition of double-low cultivars of winter oilseed rape was determined at 11 sites in England during 1989-1991. Significant (P ? 0.05) mean seed yield responses to applied sulphur (S) of 10 and 17% were obtained at two sites on sandy soils in northern England which showed symptoms of severe S deficiency. At a third site on a shallow calcareous soil in south-west England, which did not show S deficiency symptoms, seed yield was consistently but not significantly increased by an average of 8%. At one of the sites in 1989, application of ammonium sulphate caused leaf scorch and, at the maximum rate of S applied, seed and oil yield were decreased. No conclusions were reached regarding the amount of S required for maximum yield response. The S treatments decreased seed oil content by an average maximum of 9 mg g^?1. Seed glucosinolate content was increased by a greater amount at the two sites in northern England compared to other sites, where increases averaged only 3 μmol g^?1. Analysis of individual glucosinolates in the harvested seed from one of the sites in northern England showed that only the alkenyl glucosinolates were increased by S application. Yield responses were best predicted by total S concentrations and N : S ratio values in young fully-expanded leaves at flowering. Foliar-applied elemental S was consistently less effective in raising leaf S content than ammonium sulphate. Gypsum was occasionally found to be less effective than ammonium sulphate as an S fertiliser.     

Changes in yield and seed quality traits in rapeseed genotypes by sulphur fertilization

Sulphur is considered more as a soil amendment to remedy alkaline soils rather than a fertilizer in crop production. However, as one of the macronutrients, just as N–P–K, it is able to have a direct and significant effect on yield and quality in some crops. There might be a sound potential of increasing seed yield and quality of rapeseed, the second important oil crop around the world, with the use of sulphur as a fertilizer in cultural practices. Our objective in this study is to determine the effects of sulphur fertilization on seed yield and several seed and oil quality traits in rapeseed. Five rapeseed genotypes were grown for two consecutive growing seasons in Çanakkale, in a RCB design with three replications. The experimental plots were given 0, 100 or 200 kg ha^?1 sulphur along with a fixed amount of 240 kg ha^?1 N. Results indicated that sulphur fertilization had positive effects on seed yield and some of the seed and oil quality components. On the other hand, excessive sulphur fertilization, or naturally occurring high levels in the soil, may have adverse effects in elevating some undesired compounds, such as glucosinolates.     

Nitrogen top-dressing requirements of winter oilseed rape

Forty-one field experiments were carried out on the spring N top-dressing requirements of winter oilseed rape in the years 1973 to 1977. The experiments were in the main rape-growing areas of England and Scotland, and almost all were on rape crops following one or more cereals. Seed and oil yield were increased by N top-dressing in 38 of the 41 experiments, with a mean requirement by satisfactory crops for about 230 kg ha^?1 of N. Those experiments with no response to N or no response beyond 90 kg ha^?1 of N were mostly low yielding and suffered from lodging, drought or bird damage. N reduced oil content by about 2% on average, but there was a considerably larger depression in 10 experiments, almost always associated with low yield, drought or lodging. N fertiliser increased the N content of the seed by about 0.5%. Timing of N application within the period mid-February to late March had little influence on seed yield or oil content but applying all or half the N in April tended to give a lower yield. There was no advantage from splitting the N application.     

Relationship between N concentration of grain and grain yield in recent winter-wheat experiments in England and Belgium,some with large yields

Eight winter-wheat experiments conducted by Rothamsted on clay soils in 1980 and 1981 formed part of an inter-institute collaborative programme on yield variation. The tests included no N and four amounts of fertiliser N up to 200 kg ha^?1, with and without spray treatments to control pests and diseases. Large grain yields—in excess of 10 t ha^?1—were often obtained, mainly where losses had been limited by sprays. In Belgium, 10 experiments during the same seasons were on a wider range of soils and had spray treatments applied to all plots. Yields exceeding 10 t ha^?1 were obtained at one site. Graphs showing the inter-relationship between grain-N %, grain yield and N uptake are used to compare the recent results with those from a 20-year study of similar data from 124 earlier Rothamsted experiments. The envelope curve delineating the range of yield and grain-N % values from these older experiments enfolded most of the more recent data points, except those deriving from the largest yields which were associated almost entirely with grain-N % values below the minimum recommended for British breadwheat. The largest grain-N uptakes were 180–190 kg ha^?1 and 170–180 kg ha^?1 in the recent Rothamsted and Belgian experiments respectively, compared with 160-170 kg in the older experiments. The linear or near-linear relationship between grain-N % and amounts of fertiliser N, established in the 20-year study, was again observed in the recent Rothamsted and Belgian experiments, with about 38 kg of added N needed to increase grain-N concentrations by 0.1%.     

Effect of drought and irrigation on the fate of nitrogen applied to cut permanent grass swards in lysimeters: Nitrogen balance sheet and the effect of sward destruction and ploughing on nitrogen mineralisation

Fuor years after ¹⁵N labelled fertiliser nitrogen (as Ca(NO₃)₂ and equivalent to 400 kg N ha^?1) was applied to permanent grass swards growing in lysimeter monoliths, approximately one-quarter remained immobilised in soil organic matter. In the intervening years similar but non-labelled applications were made. Although differing rainfall regimes applied during the experiment had significantly affected nitrogen uptake by plants and nitrate loss in drainage, they caused no significant effect on the tracer nitrogen remaining in the soil, the ranges were 85–97 kg N ha^?1 and 79–94 kg N ha^?1 respectively for the 135 cm deep clay and silt loam soil monoliths. Labelled nitrogen unaccounted for in crop, drainage or soil was presumed to have been denitrified. These losses averaged 62 and 49 kg N ha^?1 on the clay and silt loam soils respectively; again the differing rainfall regimes caused no significant differences. The ratio between estimates of labelled nitrogen denitrified and of annual nitroux oxide loss was approximately 9:1 for both soils. The conversion from permanent grass to winter wheat in autumn 1981, involving killing and then burying the sward, resulted in no pronounced increase in net mineralisation of labelled nitrogen. However, the balance between crop uptake and the quantity leached did change. Labelled nitrogen assimilated was less for the wheat (growing without addition of fertiliser nitrogen) than for the grass in its last year, and the quantity leached was considerably greater than under grass swards that were supplied with an average rainfall distribution. Following the first wheat harvest total nitrogen leached averaged 51 and 44 kg N ha^?1 on the clay and silt loam soils respectively. Rates of nitrous oxide emissions during the autumn following sward destruction were greater than in earlier years, but this enhanced loss was of short duration. The crop clearly benefited from the succession of nitrogen applications made to grass, as grain yield and total nitrogen uptake exceeded 7 t ha^?1 and 120 kg N ha^?1 respectively on both soils. These quantities exceed the national averages for winter wheat and are also considerably greater than for crops from lysimeters which received no nitrogen fertiliser throughout the experiment.     

Influence of sulphur application on protein quality, fatty acid composition and nitrogen fixation of white lupin (Lupinus albus L.)

White lupin (Lupinus albus L.) is an important source of plant protein for both humans and livestock, due to high protein content, low alkaloids level, high level of unsaturated fatty acids, price and market availability in many countries. In this paper is reported the effect of S fertilization on white N fixation capability of lupin, grain yield and chemical characteristics in terms of protein fractions, fatty acid and mineral composition. Randomized complete block design with three replicates was used, and three S applications (0, 30 and 60 kg ha^?1, respectively) for white lupin were used. The S fertilization was split into two: 50 % before sowing and 50 % in the early of March as K₂SO₄. At the same time, both the legume and oat crops were fertilized uniformly with solution of 10 kg N ha^{?1 15}N NH₄ ¹⁵NO₃ (10 % ¹⁵N atomic excess). Data indicated that under Mediterranean environment on sub-alkaline soil, white lupin produces low grain and protein; however, S application increased plant yield and N fixation. In conclusion, it seems that S fertilization to white lupin should be recommended to soils with sub-optimal S levels to obtain maximum seed and protein yields. Moreover, S fertilization enhanced the protein quality increasing its degradable fraction, and improved the lupin oil quality through the increase in oleic and linolenic acids and the remarkable decrease in erucic acid.     

The nitrogen content of potato (Solanum tuberosum L.) tubers in relation to nitrogen application—the effect on amino acid composition and yields

The effect of nitrogen application on the nitrogen content and yield of amino acids from potato tubers was studied in one experiment in 1983 and two in 1984. Increasing fertiliser N over the range 0–250 kg ha^?1 raised tuber nitrogen concentrations from 0.68–0.81 to 1.27–1.49% DM. Applying half the fertiliser on the seedbed and half at tuber initiation did not increase tuber nitrogen concentrations compared with a single broadcast application at planting. Increasing tuber nitrogen concentrations had little effect upon the proportion recovered in amides or the different amino acids. Yields of some nutritionally essential amino acids were, therefore, substantially increased up to a maximum of 256 kg ha^?1 in 1982 and 308 and 384 kg ha^?1 in 1984 at the highest fertiliser level. These yields were significantly higher (P<0.01) than those found with the nitrogen application rate optimal for tuber dry matter production (213, 195 and 331 kg N ha^?1, respectively) in the same experiments. Methionine and cystine were the limiting essential amino acids. As the amount of each amino acid contained in a unit weight of fresh tuber increased with nitrogen supply, application of more nitrogen than is needed for maximal tuber dry matter production increased protein yields without decreasing the nutritional quality.     

Effect of nitrogen application rate on the content and composition of oil,essential oil and minerals in black cumin (Nigella sativa L.) seeds

A field experiment was conducted to study the effect of nitrogen fertility level on the content and composition of oil, essential oil and minerals in black cumin (Nigella sativa L.) seeds. Sixty‐three‐day‐old plants were supplied with varying levels of N, i.e., 0, 30, 60, and 90 kg N ha^?1 soil. The fixed oil content of the seeds ranged from 32.7% to 37.8% and it remained almost unchanged at the two higher external N regimes, i.e., 60 and 90 kg N ha^?1, but at 30 kg N ha^?1 the oil content increased significantly. Of the saturated fatty acids analyzed, palmitic acid increased slightly at all external N levels, but in contrast stearic acid decreased considerably at 60 kg N ha^?1. Of the unsaturated fatty acids of fixed oil, the predominant fatty acid was linoleic acid (18:2) followed by oleic acid (18:1). Linoleic acid and dihomolinoleic acid (20:2) showed no change in their amounts at varying levels of N. In contrast, a marked reduction in α‐linolenic acid (18:3) was found at the two higher N regimes, i.e., 60 and 90 kg N ha^?1. Seed essential oil content did not vary with the change in applied N level. The major component of essential oil of black cumin seed was found to be p‐cymene, which showed an increase at 30 kg N ha^?1, whereas no change in the levels of α‐pinene or β‐pinene was observed at varying levels of N. K, P, Na, Fe, Mn, and Ni were found to be predominant elements in the seeds. Ca, Mg, Cu, and Cr were present in low amounts, but Zn was present in moderate quantity. Increasing N rate did not affect the content of K, P, Ca, Mg, or Cr in the cumin seeds. In contrast, a consistent decrease in seed Mn, Zn, and Ni was observed with increase in external N level. Increasing N level had a marked effect on some of the components of black seed oil. Copyright © 2006 Society of Chemical Industry     

Effect of drought and irrigation on the fate of nitrogen applied to cut permanent grass swards in lysimeters: Leaching losses

Nitrogen losses were measured in water draining from cut permanent grass swards growing in monolith lysimeters containing clay loam (Salop series) or silt loam (Bromyard series) soils. The swards were cut at 6-week intervals during the summer and were fertilised with calcium nitrate at rates of 0 and 400 kg N ha^?1 in each of five successive years (1977–81); in the first year the fertiliser was labelled with ¹⁵N. Four differing rainfall regimes were imposed from spring to autumn in each year. Mean annual losses of nitrogen by leaching from unfertilised swards were 3.8 kg N ha^?1 with mean nitrate-N concentrations in the water of about 1 mg N litre^?1. In fertilised lysimeters where rainfall distribution was that of the long-term average the mean annual total nitrogen losses were 41 kg N ha^?1 in the Salop soil and 15 kg N ha^?1 for the Bromyard soil; mean nitrate-N concentrations were 11.6 mg N litre^?1 and 5.1 mg N litre^?1, respectively. Losses of nitrogen and nitrate concentrations were similar to these quantities when irrigation increased the rainfall total to 120% of average. Where a drought was imposed for 2 weeks before and after each cut, mean nitrate-N concentrations increased to 20.3 mg N litre^?1 on Salop soil and 13.1 mg N litre^?1 on Bromyard soils; total annual nitrogen losses were 74 kg N ha and 33 kg N ha^?1, respectively. The largest losses were recorded when the drought period extended for four weeks before each cut and mean nitrate-N concentrations increases to 28.8 mg N litre^?1 on Salop soil and 34 mg N litre^?1 on Bromyard soil, with total annual nitrogen losses of 104 kg N ha^?1 and 109 kg N ha^?1, respectively. Losses of nitrogen derived from the fertiliser labelled with ¹⁵N were 7.3–8.4% of that applied in the Salop soil (29–33 kg N ha^?1), with little effect by the differing rainfall distributions. On the Bromyard soil, losses were 3.7% (14 kg N ha^?1) of the applied fertiliser in lysimeters not subjected to droughts. When the period of the drought extended before and after each cut, losses were 8.2% (32 kg N ha^?1) and increased to 17.9% (70 kg N ha^?1) when the drought period occurred entirely before each cut. Fertiliser nitrogen contributed 48–69% of the total nitrogen in drainage water from both soils in the first year.     

Responses of Cereals to Residual Fertiliser Nitrogen Applied to the Preceding Potato Crop

The effects of N fertiliser and poultry manure, applied to potato crops, on soil mineral N (SMN) after harvest and on the grain N offtake (N_off) and yield of subsequent unfertilised cereal crops, were measured at six sites in England during 1989–1994. At three sites of medium textured soil N_off increased by between 0 and 49 kg ha^-1 and grain yield by between 0 and 2·1 t ha^-1, with increasing potato fertiliser N (PFN). The increases were greatest at applications of fertiliser N in excess of the optimum requirement for potatoes. No responses were found on two sandy and one shallow soil. Poultry manure applied in autumn or spring before the potatoes were planted increased N_off by between 0 and 52 kg ha^-1 and yield by between 0 and 2·1 t ha^-1 at one site on medium textured soil but not on one of the two sandy soils. These results suggest that, at the rates of fertiliser N currently recommended for potatoes, the N requirement of subsequent cereal crops may be reduced by between 20 and 40 kg ha^-1 on retentive soils but not on sandy and shallow soils. These reductions are less than currently recommended. However, the results also suggest that adjusting cereal fertiliser N according only to previous crop is unsatisfactory. The range of fertiliser N applied to potato crops in commercial practice is sufficiently great to significantly affect N_off, yield and hence the fertiliser N requirement of the subsequent cereal crop. © 1997 SCI.     

The effects of irrigation,nitrogen fertilizer and grain size on Hagberg falling number,specific weight and blackpoint of winter wheat

The effects of irrigation and nitrogen (N) fertilizer on Hagberg falling number (HFN), specific weight (SW) and blackpoint (BP) of winter wheat (Triticum aestivum L) were investigated. Mains water (+50 and +100 mm month^?1, containing 44 mg NO₃^? litre^?1 and 28 mg SO₄^2? litre^?1) was applied with trickle irrigation during winter (17 January–17 March), spring (21 March–20 May) or summer (24 May–23 July). In 1999/2000 these treatments were factorially combined with three N levels (0, 200, 400 kg N ha^?1), applied to cv Hereward. In 2000/01 the 400 kg N ha^?1 treatment was replaced with cv Malacca given 200 kg N ha^?1. Irrigation increased grain yield, mostly by increasing grain numbers when applied in winter and spring, and by increasing mean grain weight when applied in summer. Nitrogen increased grain numbers and SW, and reduced BP in both years. Nitrogen increased HFN in 1999/2000 and reduced HFN in 2000/01. Effects of irrigation on HFN, SW and BP were smaller and inconsistent over year and nitrogen level. Irrigation interacted with N on mean grain weight: negatively for winter and spring irrigation, and positively for summer irrigation. Ten variables derived from digital image analysis of harvested grain were included with mean grain weight in a principal components analysis. The first principal component (‘size’) was negatively related to HFN (in two years) and BP (one year), and positively related to SW (two years). Treatment effects on dimensions of harvested grain could not explain all of the effects on HFN, BP and SW but the results were consistent with the hypothesis that water and nutrient availability, even when they were affected early in the season, could influence final grain quality if they influenced grain numbers and size. Copyright © 2004 Society of Chemical Industry     

Some relationships between grain yield and grain protein of wheat experiments in south-east england and comparisons with such relationships elsewhere

By adopting a uniform method of presentation, the interrelationship between grain yield, %N in grain and N uptake (or protein yield) from diverse experiments and surveys can be compared readily. All three variables can be shown together by plotting yield vs %N and adding the third variable in the form of hyperbolic lines representing equal N uptake (or protein yield). This method is used in two diagrams which display 2000 values derived from 124 experiments on winter wheat and 400 values from 41 experiments on spring wheat, conducted by Rothamsted Experimental Station over 20 years. Both scatter diagrams display well-defined boundaries which have been emphasised by linking points along these boundaries to form ‘envelope curves ’For winter wheat the maximum yield was 9.5 t ha^?1, the largest N concentration about 3% and the largest N uptake 170 kg N ha^?1 (about 970 kg protein ha^?1). Spring wheat had a maximum grain yield of 6.3 t ha^?1, the largest N concentration was 3.1% and the largest N uptake 125 kg N ha^?1. Four examples of other work set within the same framework show applications of our method of presentation. Results from a recent more homogeneous series of experiments in southern England (conducted by the Agricultural Development and Advisory Service), showing clear seasonal differences, are seen to lie within the envelope curve defined by the Rothamsted experiments. Further illustrations are taken from an experiment by the Plant Breeding Institute, Cambridge, comparing varieties of different bread-making qualities, from work of the Nebraskan plant breeding team who have produced grain with larger protein content without sacrificing yield, and from survey data for England and West Germany.     

The fertiliser nitrogen requirement of cereals grown on sandy soils

The responses to fertiliser‐N of winter wheat and winter barley grown on sandy soils were measured in 72 experiments in England from 1990 to 1994. Yield without fertiliser‐N (Y₀) was c 1.1 t ha⁻¹ greater following root crops than following cereals. Following potato crops given organic manures, Y₀ was c 1.2 t ha⁻¹ greater than following unmanured potato crops, but Y₀ was no greater following sugarbeet to which organic manures had been applied. Only after the two driest winters was there sufficient variation in soil N supply in spring (SNS_s) for this to show a relationship with Y₀. However, Y₀ increased with increasing N mineralisation during the growing season (AM) in the three years it was measured. There was no consistent effect of sowing date on Y₀. Following potatoes, yield at optimum fertiliser‐N (Y_opt) decreased as sowing date was delayed, but this was not so after cereals, sugarbeet or overall. There was no increase in Y_opt with SNS_S or AM, but Y_opt decreased with increasing moisture stress (S) in June. The mean yield response to N_opt (Δ_Y) was c 0.4 and 0.8 t ha⁻¹ smaller following potatoes and sugarbeet respectively than following cereals, but not consistently so as there were large interactions between site, year and previous crop. Following root crops, Δ_Y was c 0.6 and 1.4 t ha⁻¹ less after sugarbeet and potatoes respectively that had been given organic manures. Without the addition of organic manures, Δ_Y following potatoes was similar to that following cereals. Regression on SNS_S and AM accounted for 28 and 15% respectively of the variance in Δ_Y. The optimum economic fertiliser‐N application (N_opt) was similar, at c 140 kg ha⁻¹, following cereals and potatoes. Following sugarbeet, cereal N_opt was only c 110 kg ha⁻¹. The differences according to previous crop reported here are consistent with mineralisation of crop residues on sandy soils being more rapid than on other soils; the potato residues were rapidly mineralised in autumn and lost by leaching over winter. Residues from later‐harvested sugarbeet were mineralised during the growing season of the subsequent cereal crop. Fertiliser‐N requirements were, at c 110–140 kg ha⁻¹, smaller than has been found on other soil types, and less than current recommendations for wheat. Requirements were significantly reduced in years of drought stress. No differences were found in N_opt between wheat and barley. These data do not justify the current advice to invariably reduce fertiliser‐N to cereals following potatoes by 20–25 kg ha⁻¹ on these sandy soils. On average a reduction of c 20 kg ha⁻¹ could be made following sugarbeet, with a further reduction of c 40 kg ha⁻¹ N if manures had been applied to the previous sugarbeet crop. A reduction of 40 kg ha⁻¹ N could also be made where cereals followed a potato crop to which manures had been applied. Further refinements on the basis of measurements of soil mineral N could not be justified. Seasonal variation in N response due to drought stress makes recommendations difficult on these soils. Adopting the fertiliser‐N recommendations proposed here would produce N surpluses to the soil of c 37, 10 and 27 kg ha⁻¹ respectively following cereals, sugarbeet and potatoes when cereal grain is removed but straw incorporated. On farms where straw is removed, N surplus would be largely eliminated. Our recommendation that no reduction in fertiliser‐N application to cereal crops grown on sandy soils should be made following potatoes will not increase fertiliser‐N use and is not expected to increase nitrate leaching. Some reduction in nitrate leaching may be achieved if recommendations following cereal crops and sugarbeet are made in accordance with the results reported here. © 2000 Society of Chemical Industry     

Effect of temperature,carbon dioxide enrichment,nitrogen form and rate of nitrogen fertiliser on the yield and nitrate content of two varieties of glasshouse lettuce

Head weight of winter glasshouse lettuce was increased slightly by higher temperature (7°C day/4°C night and 10°C day/7°C night) and carbon dioxide enrichment (350 and 1000 μl litre^?1) but, despite faster growth, plant nitrate concentration was unaffected. Addition at the lowest rate (138 kg ha^?1 N) of ammonium nitrate, calcium nitrate and urea increased plant nitrate by a similar amount compared with nil fertilizer nitrogen, but addition of more fertilizer (276 kg ha^?1 N) had no further effect. Urea produced a lower yield than the other two N sources. Coated controlled-release nitrogen produced both low yields and low plant nitrate concentrations because its nitrogen release rate was too slow to keep pace with plant growth. The most effective material in terms of high yield and low plant nitrate was one containing a nitrification inhibitor within the fertiliser granules.     

Interrelationship between nitrogen concentration in grain,grain yield and added fertiliser nitrogen in wheat experiments of South-east England

Results from 20 years of wheat experiments were used to compare responses of grain-N% and grain yield to increasing amounts of fertiliser-N. Grain-N% for both winter and spring wheat increased, mostly linearly, throughout the range, whereas many of the grain yield curves reached a maximum and then declined with further additions of N. Provided curve sections exhibiting dilution effects were excluded, the linear or near-linear relationship between grain-N% and fertiliser-N allowed linear regression models to be fitted. This showed that, over a range of 50-175 kg N ha^?1, an average of 32 kg ha^?1 of fertiliser-N was required for an increase of 0.1% N in grain dry matter of winter wheat or 56 kg N ha^?1 for an increase of 1% protein. Results from 3 years of experiments conducted by the Agricultural Development and Advisory Service (ADAS) agreed closely with those obtained from Rothamsted. Using the linear relationship between grain-N% and fertiliser-N, curves were plotted of grain yield against grain-N, adjusted for comparable additions of fertiliser-N (75, 100, 125, 150 kg ha^?1). The curves tended to have sections with rising yield for small applications of N, to exhibit a maximum in a central zone and descending sections for large applications. There was no well-defined ?critical level’? of grain-N%, beyond which this and grain yield were inversely related.     

Effect of residual fertility and direct fertilisation on kernel,protein and oil yield of peanut (Arachis hypogaea L) grown in rice fallows

Kernel (2814–3467 kg ha^?1), protein (555–759 kg ha^?1) and oil (124–1556 kg ha^?1) yields of peanut (Arachis hypogaea L) varied significantly due to the residual effect of organic manures and inorganic fertilisers together. It was also observed that direct application of recommended fertilisers (25 N, 72 P₂O₅ and 37-5 K₂O kg ha^?1) gave the highest kernel (3669 kg ha^?1), protein (786 kg ha^?1) and oil (1606 kg ha^?1) yields. The reduction in kernel, protein and oil yield from the recommended level of fertilisers to half the recommended level of fertilisers was about 16, 15 and 12% while it was about 25, 33 and 27% with no fertiliser. Thus, the results revealed that the nutrients applied partly through organic manures and inorganic fertilisers to Kharif rice exhibits significant residual effects on the succeeding upland crop and hence the fertilisation must be considered not only for individual crops but also for the cropping system as a whole.     

Influence of nitrogen fertilizer application rate on winter wheat (Triticum aestivum L.) flour quality and Chinese noodle quality

BACKGROUND: Understanding wheat flour noodle quality responses to N management will improve the quality of recommendations made to growers for specific end‐uses. Two winter wheat cultivars, with six N rates, planted during the course of a 2‐year experiment were used to determine the effect of N application rate on Chinese white noodle quality. RESULTS: Wheat flour protein content, development time (DT) and stability time (ST) increased with N application rate, maximal at 360 kg N ha^?1 and decreasing thereafter. When the N fertilizer application rate changed from 0 to 270 or 360 kg N ha^?1, redness (a*) and yellowness (b*) of both flour and noodle increased, while brightness (L*) decreased. The hardness and chewiness of cooked noodles improved at lower N application rate and degenerated at higher N rate. CONCLUSION: A low rate of N fertilizer application (from 0 to 270 kg N ha^?1) improved flour quality. Flour protein content and protein quality parameters displayed a significant negative correlation with brightness (L*) values. Generally, high flour protein content and protein quality, as well as good noodle texture, could be achieved by topdressing N fertilizer (in the range 270–360 kg N ha^?1). Copyright © 2009 Society of Chemical Industry