Effects of form and amounts of nitrogen and magnesium fertilisers on the yield and on the inorganic and organic composition of italian ryegrass grown on magnesium deficient soil

Italian ryegrass (Lolium multiflorum) S22, grown in Mg-deficient soil in pots, was given 40 and 160 mg N/kg of soil as ammonium nitrate or as ammonium sulphate treated with a nitrification inhibitor and 0, 20 and 40 mg Mg/kg of soil as magnesium sulphate. Yields of grass given the larger dressing of N were greater with ammonium nitrate than with ammonium sulphate. The magnesium treatments significantly increased yields only of the third cut given the most N when concentrations of Mg in dry matter were 0.07% or less. Magnesium fertiliser had little effect on the production of reducing sugars and sucrose but markedly increased fructosan and percentages of chlorophyll in grass of the third cut given the larger dressing of N. Non-protein nitrogen was much greater with ammonium sulphate than with ammonium nitrate nutrition. With both forms of N fertiliser, this fraction accumulated in grass grown without added Mg, but it decreased when Mg-deficiency was corrected. The percentage distribution of N in the free amino acid pool varied with the form of N fertiliser and the Mg treatments. With grass given ammonium nitrate, free amino acids predominated over amides; the reverse was true for grass given ammonium sulphate. The main effect of adding Mg was to decrease glutamine and to increase the percentages of some free amino acids, especially alanine and γ-aminobutyric acid. About half of the soluble organic N in grass given ammonium nitrate was unaccounted for as amino acids and amides with all the Mg treatments; this N fraction was much less in grass given ammonium sulphate, but it increased with increasing magnesium fertiliser.     

Sulphur–nitrogen interaction effects on the yield and composition of the protein-N,non-protein-N and soluble carbohydrates in perennial ryegrass

In a controlled-environment pot experiment sulphur fertilisers increased the yields of ryegrass when large dressings of nitrogen were also given. Yield responses to sulphur occurred when the dry matter contained less than 0.20% S. At the third cut, sulphur deficiency decreased concentrations of reducing sugars but had little effect on sucrose and fructosan in the grass dry matter. Only 44% of the nitrogen in the most sulphur-deficient grass was protein-N as compared to over 80% in non-deficient grass. The non-protein-N accumulated predominantly as amides especially asparagine. The amino acid composition of the insoluble protein, including the proportions of cystine and methionine, was unaffected by acute sulphur or nitrogen deficiencies.     

Effect of replacing potassium by sodium on growth and on inorganic and organic composition of Italian ryegrass

Two pot experiments, one with 2³ factorial (1969) the other with 3³ factorial (1970) N × K × Na design, showed that yields of Italian ryegrass (Lolium multiflorum) were increased by both potassium and sodium, when sufficient nitrogen was given but responses to potassium were larger than to sodium. Yields were only increased by potassium fertiliser when the grass contained less than 2.0 % K in the dry matter, irrespective of the Na content. The main effect of potassium and sodium on the soluble carbohydrates was to increase the production of fructosan; again potassium was more effective than sodium. Total N concentrations in the grass decreased with the increased production of dry matter from potassium and sodium fertilisers. Ammonium N, nitrate N and soluble organic N (expressed as the percentage of total N) were also decreased by potassium and sodium. In 1969, both potassium and sodium increased the percentages of most amino acids and decreased the percentages of asparagine and glutamine within the free amino acid pool; potassium was more effective than sodium. In 1970, sodium alone had little effect on the percentage distribution of free amino acids. Under conditions of severe potassium deficiency sodium can substitute to some extent for potassium in its effects on yields, soluble carbohydrates and various N fractions.     

Effects of nitrogen and potassium fertilisers on contents of carbohydrates and free amino acids in Italian ryegrass: I.—Effects on growth and soluble-carbohydrate contents of leaves,stubble and roots

Italian ryegrass S22, grown in K-deficient sandy loam in pots under glass, was given 40,80 and 160 ppm N as ammonium nitrate and 0, 60, 120 and 240 ppm K as potassium chloride. In the absence of K fertiliser, increasing N fertiliser decreased root weights, but with the largest dressing of K, grass which was given high rates of N produced more roots than grass receiving the smallest amount of N. K fertiliser increased root weights and the content of soluble carbohydrates in roots. Irrespective of K supply, roots contained very little fructosan. Adequate K was needed to give maximum amounts of sugars and fructosan in the tops and stubble. Excessive K in relation to N fertiliser was detrimental to the accumulation of fructosan in the stubble. The importance of the effect of K on soluble carbohydrates is briefly discussed.     

Effects of nitrogen and potassium fertilisers on contents of carbohydrates and free amino acids in Italian ryegrass. II. Changes in the composition of the non-protein nitrogen fraction and the distribution of individual amino acids

Italian ryegrass (Lolium multiflorum) S22, grown in a greenhouse in K-deficient soil in pots, was given 40, 80 and 160 mg of N/kg of soil (as ammonium nitrate) and 0, 60, 120 and 240 mg of K/kg of soil (as potassium chloride). In grass grown without added K, increasing N fertiliser increased the concentrations of total N, non-protein-N, ammonium-N, nitrate-N, free amino acids, amides and amines. With adequate K fertiliser all these N fractions decreased. The percentage distribution of N in the free amino-acid pool varied with the amount of N and K given. Without K fertiliser, increasing N had no consistent effect on most amino acids and amides, although it decreased the percentages of alanine and ethanolamine. Increasing K had relatively little effect on the percentage distribution in grass given the two smaller amounts of N. However, in the grass given the largest amount of N, it increased the percentage of most amino acids, especially alanine and 4-amino-n-butyric acid, and decreased glutamine and asparagine. β-Alanine was found only in K-deficient plants. The effect of K in relation to N metabolism and the nutritive value of herbage is briefly discussed.     

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.     

Water-soluble carbohydrates in extracts from large-scale preparation of leaf protein

Soluble carbohydrate accounted for about half of the 2% dry matter in liquors from heat-coagulated leaf extracts made during large-scale preparation of protein from agricultural crops. The fraction soluble in 80% ethanol contained on average three-quarters of the total carbohydrate and the sugars were fructose, glucose and sucrose, with traces of xylose. The insoluble fraction was mostly fructosan in ryegrass, there was less in lucerne and very little in mustard; other sugars besides fructose released on acid hydrolysis were arabinose, glucose, galactose and xylose.     

Changes in chemical composition during development of grass pea (Lathyrus sativus L.) seeds

The level of chemical components was determined in seeds of grass pea (Lathyrus sativus L.), cv. Krab, harvested at a dry matter content between 25.9 and 49.6 g/100 g of the raw material, and divided into five degrees of maturity. The results presented suggest that, in general, with an increasing maturity of seeds, the level of the following components increased if related to fresh matter: starch, dietary fibre, acids, total and protein nitrogen, total amino acids and sulphur amino acids, ash and its alkalinity, magnesium, calcium, total phosphorus and phytic phosphorus, and thiamine. The following components were reduced: vitamin C, riboflavin, carotenoids, beta-carotene, and chlorophylls. No such regularity could be found with respect to the accumulation of sugars, essential amino acids, and iron. By expressing the results in dry matter, increases were noted in starch, protein nitrogen, and thiamine. The content of sugars, total nitrogen, total amino acids, essential and sulphur amino acids, ash and its alkalinity, magnesium, phosphorus, vitamin C, riboflavin, carotenoids, beta-carotene, and chlorophylls were reduced while that of dietary fibre, iron, calcium, and phytic phosphorus varied.     

Nutritive value of potato crude protein as influenced by manuring and amino acid composition.

Potatoes were grown in pots and fertilised with varying amounts of nitrogen (as nitrate or ammonium sulphate or urea), phosphorus, potassium and cow manure. The largest yield, 451 g DM per pot, was obtained with nitrogen in the form of urea. N-applications and P- and K-deficiency in the soil increased the total-N content, which varied from 1.14–3.07%. Concentrations of nitrate-N (0.001–0.016%) were negligible. Increasing N-concentrations were associated with decreases in the crude protein of most amino acids including lysine (6.26–4.17%), threonine (4.08–2.90%), methionine (1.98–1.46%) and tryptophan (1.74–0.86%). The concentrations of aspartic and glutamic acids (probably mainly present as their amides) increased. Differences in amino acid composition between boiled and unboiled potatoes were negligible. From 70 to 90% of the decrease in concentration of most essential amino acids could be accounted for by changes in N-content of dry matter. Phosphorus and potassium affected the amino acid composition indirectly through their effects on N-content. In rat feeding experiments increasing N-concentrations in potatoes increased the true digestibility of the crude protein from 79 to 91 but decreased the biological value from 82 to 59. The net protein utilisation did also decrease (from 67 to 54). These relationships were linear below 2.2% N in dry matter. Changes were mainly dependent on variations in N-content. Decreases in essential amino acid indices or chemical scores were closely reflected in the results of the feeding experiments. The true amino acid digestibilities were different for individual amino acids and increased with increasing N-concentration in dry matter.     

Effects of grazing and nitrogen fertiliser on the soil microbial biomass under permanent pasture

Carbon and nitrogen in the soil microbial biomass were measured on eight occasions during a grassland production season, under swards of perennial ryegrass receiving 210 or 420 kg N ha^?1 per year or of ryegrass/white clover receiving no fertiliser N. The swards were either cut or grazed at monthly intervals. Soil microbial biomass C increased under all treatments in late April before declining until late July and rising slowly towards the end of the season. Values for microbial C under cutting and grazing were not significantly different but were usually larger under grass/clover than under grass. In contrast, the smallest values for soil microbial biomass N were recorded in late April. Larger N values were again recorded under grass/clover, and although values were nearly always smaller under grazing than under the corresponding cut treatment the differences were not significant. Soil biomass N comprised a large reservoir of mobile N, and at any one time contained 11, 3 and 5 times more N than was present in the mineral N component of the soil, the standing crop or excretal returns, respectively. It did not appear to be responsive, within a season, to the considerable returns of C and N from grazing animals or to N fertiliser management.     

The digestibility of grass silage by sows

Silage made from young grass and which contained an average of 34.6 g nitrogen (N), 19.5 MJ gross energy (GE) and 271 g fibre/kg dry matter (DM), was found to have digestibility coefficients to sows of 0.73 for N, 0.60 for GE, 0.60 for cellulose and 0.51 for fibre. The addition of a cellulase enzyme preparation to the grass prior to ensilage decreased the fibre content by 38 g/kg DM and increased the water soluble carbohydrate (WSC) content by 154 g/kg DM, but did not influence the digestibility of the silage.     

解磷细菌肥对烤烟磷素吸收和磷肥利用率的影响

为探究解磷细菌肥对烤烟磷素吸收和磷肥利用率的影响,以云烟87为供试品种,设置解磷细菌肥（0、75 kg/hm²）与磷肥（0、1250 kg/hm²）的双因素随机区组试验,分析了烤烟根际土壤有效磷、微生物、根系活力、干物质积累量和各器官磷素吸收的变化。结果表明,解磷细菌肥配施磷肥可极显著提高烤烟根际土壤有效磷含量,显著提高烤烟根际土壤可培养细菌数量,提高烤烟根际土壤微生物AWCD,极显著提高土壤微生物对碳水化合物、氨基酸和胺类碳源的利用能力,改变微生物群落碳源代谢特征;显著提高了烤烟根系活力,促进了干物质量积累和磷素吸收,磷肥利用率显著提高了4.89%。     

江西红壤旱地花生测土施氮参数研究

以粤油256为供试品种,选取高、中、低肥力的红壤旱地共10块,设计0、135kg/hm2两个施氮水平,研究江西红壤旱地花生测土施氮的参数。结果表明,随着土壤肥力水平的上升,花生产量、生产100kg花生荚果的需氮量、土壤供氮量和土壤氮素贡献率随之提高,而氮肥表观利用率随之下降。高、中、低肥力地块的土壤供氮量分别为222.65kg/hm2、181.53kg/hm2、140.67kg/hm2,土壤氮素贡献率分别为84.88%、79.92%、74.45%,氮肥表观利用率分别为29.37%、33.70%、35.51%;在不施氮条件下生产100kg花生荚果的需氮量分别为6.52kg、6.39kg、6.34kg,而在N135条件下分别为6.60kg、6.44kg、6.37kg。相关分析表明,花生产量、土壤供氮量和花生需氮量与土壤肥力指标中的有机质、全氮、碱解氮、速效钾含量有显著或极显著正相关,而与有效磷含量相关不显著;氮肥利用率与5项土壤肥力指标都呈负相关,但不显著。通过逐步回归,建立了花生产量、土壤供氮量、花生需氮量、氮肥利用率与土壤肥力指标的回归方程,为红壤旱地花生测土施氮提供指导。     

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.     

贺兰山东麓酿酒葡萄园土壤肥力特征与空间变异

通过多点采样分析研究了贺兰山东麓主要酿酒葡萄产区土壤肥力特征及其空间变异特征.结果表明:贺兰山东麓酿酒葡萄高产土壤与低产土壤肥力差异明显.依赖化肥的低产田,其土壤速效氮、钾含量高于高产田,且变异系数大,速效磷则相反;高产酿酒葡萄园土壤有机质含量比低产园4 g/kg左右,且变异系数小.除风沙土外,贺兰山东麓高产酿酒葡萄园有机质含量应大于18 g/kg,碱解氮50 mg/kg,速效磷大于25 mg/kg,速效钾大于140 mg/kg,全盐含量0.5 mg/kg以下.通过施用有机肥增加土壤有机质含量是获取酿酒葡萄适度高产的最有效途径,过量施用化肥尽管可以使速效性氮磷钾含量达到丰富的水平,但不能实现稳产和高产.     

The influence of two soil nitrogen levels on the utilisation of 15N-labelled ammonium nitrate by ryegrass

In a field plot experiment with grass under cutting management, two soil organic nitrogen levels (0.92% and 1.14% in the top 75mm of soil) were created by repeated applications of pig slurry over a period of 8 years. The influence of soil organic nitrogen level on the recovery by ryegrass of ammonium nitrate fertiliser was then studied by reseeding the plots and applying ¹⁵N-labelled fertiliser at four rates (40, 80, 120, 160kg N ha^?1). After each of the first four cuts unlabelled ammonium nitrate fertiliser was applied at these same rates. The percentage utilisation of the labelled fertiliser was measured in five harvests over 2 years. At the first cut the percentage utilisation averaged 46.4% and was independent of fertiliser rate and soil organic nitrogen level. The average percentage utilisation values in cuts 2, 3, 4 and 5 were 9.9, 2.4, 0.8 and 0.5 respectively. For the total of all cuts it was only at the 40 kg N ha^?1 fertiliser rate that the percentage utilisation was significantly different (P<0.05) between the 0.92% and 1.14% soil organic nitrogen levels, at 49.0% and 61.4% respectively. The soil nitrogen contribution to ryegrass at the first cut was significantly increased (P<0.05) by the high soil organic nitrogen level at the 40 and 160 kg N ha^?1 fertiliser rates. Over all fertiliser rates the average soil nitrogen contribution to the first cut was 50.4 and 61.1 kg N ha^?1 at the 0.92 and 1.14% soil organic nitrogen levels respectively. From the first cut data, soil organic nitrogen was estimated to have a net mineralisation rate of 2.6% year^?1 and a half-life of 26 years.     

Nitrogen fractions and soluble carbohydrates in Italian ryegrass II.—Effects of light intensity,form and level of nitrogen

S.22 Italian ryegrass grown in a glasshouse during June on clay loam soil at three light intensities (100, 68 and 44% of daylight), was given 6 amounts of N (0–500 ppm) as NH₄⁺-N or NO₃^?-N. Grass grew best in 100% daylight, and with NH₄⁺-N yields were most at 500 ppm and with NO₃^?-N at 200 ppm. Total-N, total soluble-N and nitrate-N, were much more, and protein-N, amide-N (psrticularly asparagine-N) and α-amino-N much less in grass given NO₃^?-N than in grass given NH₄⁺-N. These differences increased with increasing amounts of applied N. Shading, or increasing the amount of N increased total-N, total soluble-N, soluble organic-N and nitrate-N, and decreased protein-N and soluble carbohydrates. Light intensity had most effect on the amount of solyble carbohydrates in grass given 100 ppm of N and the effect decreased with increasing amounts of N. ‘N-Serve’ indirectly influenced the chemical composition of grass by maintaining N in the soil in the NH₄⁺-N form.     

火土灰对烟草苗期根系生长及根际养分的影响

为明确火土灰对烟草根系生长的影响,采用盆栽试验研究了火土灰不同施用量（CK：不施火土灰,T1：2%火土灰,T2：4%火土灰,T3：8%火土灰）对烟草苗期根际土壤pH、土壤养分、根系形态及烟苗氮磷钾养分吸收的影响。结果表明：（1）与CK相比,不同火土灰处理均能显著提高根际土壤速效钾和有效磷含量,而降低根际pH 0.37~0.59个单位;（2）与CK相比,T1、T2与T3处理烟株地上部干物质量分别增加21.94%、38.76%和80.24%,根系干物质量分别增加67.50%、92.50%和87.50%;施用火土灰处理能显著增加植株根系总根长、根系表面积和根系体积;（3）与CK相比,不同火土灰处理能显著增加烟株地上部氮磷钾积累37.88%~88.05%、48.95%~55.77%和34.16%~109.33%;显著增加根系氮磷钾元素积累量71.17%~97.75%、45.34%~66.91%和87.27%~128.99%。综上,施用8%火土灰在改善土壤养分、增加烟株苗期生物量以及提升烟株养分积累方面均具有显著效果。     

酸性黄棕壤中钼磷配施对甘蓝型油菜苗期碳氮代谢的影响

利用酸性黄棕壤进行盆栽试验,研究了钼磷配施对甘蓝型油菜苗期碳氮代谢的影响。结果表明,施钼和施磷均显著增加叶片叶绿素含量、光合速率、可溶性总糖含量以及地上部干物质重和可溶性蛋白质含量,显著降低油菜苗期叶片硝态氮含量;且钼肥和磷肥配施对促进油菜苗期碳氮代谢存在协同效应。钼肥和磷肥提高油菜光合速率的机制有所不同,钼肥主要提高叶肉细胞光合活性,而磷肥则增加气孔导度。     

Dissolved free and combined amino acids in surface runoff and drainage waters from drained and undrained grassland under different fertilizer management

Organic matter is a valuable resource on which the sustainability and productivity of soils relies heavily. Thus, it is important to understand the mechanisms for the loss of organic compounds from soil. It is also essential to determine how these losses can be minimized, especially those resulting from anthropogenic activity. Grazed grassland lysimeters (1 hectare) were used to examine the contribution and distribution patterns of dissolved free and combined amino acids to dissolved organic nitrogen and carbon in surface runoff and drainage waters from a grassland soil over three winter drainage periods. The waters were collected from soils beneath drained and undrained permanent ryegrass swards, receiving 0 and 280 kg ha(-1) year(-1) mineral nitrogen (N) input. Total dissolved free amino acid (DFAA) and dissolved combined amino acid (DCAA) concentrations ranged between 1.9 nM and 6.1 microM and between 1.3 and 87 microM, respectively. Although addition of mineral N fertilizer increased both DFAA and DCAA concentrations in waters, there was no detectable effect of soil hydrology or fertilizer addition on distribution patterns.