bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic and chemical sources of nitrogen: its effect on nitrogen transformation and rice productivity under submerged conditions
Authors: Chakraborty P. K. , Mandal L. N. , Majumdar Anup 
Published: March 2009

SummaryA field experiment was carried out in three wet seasons of 1982, 1983 and 1984 with various combinations of urea and organic nitrogen sources to investigate the nitrogen transformation and productivity of rice crop in a waterlogged situation. The treatments used were: (i) control (No), (ii) FYM + urea, (iii)Sesbania+ urea, (iv) urea, the levels of nitrogen being 60 and 90 kg/ha and the proportion being 50:50 between organic and chemical sources where such combination was used. The soil samples were analysed for ammonium, hydrolysable and non-hydrolysable forms of nitrogen at 15, 30 and 45 days after transplanting. The release of hydrolysable and non-hydrolysable nitrogen was superior in theurea-Sesbaniacombination while the release of NH4·N was slightly better in FYM-urea combination. Yield of rice and apparent nitrogen use efficiency were highest in sole urea treatment and almost similar in FYM-urea andSesbania+ urea combinations. A statistical nitrogen-transformation model outlined the relationship among the various forms of soil nitrogen under submergence. The model suggested a strong correlation among the different forms of nitrogen during the earlier period of submergence.
Influence of salinity, rice straw and water regime on nitrogen fixation in paddy soils
Authors: Jena P. K. , Rajaramamohan Rao V. 
Published: March 2009

SummaryIn a laboratory incubation study, the effect of natural and artificial soil salinity on the soil N2fixation, nitrogenase (C2H2reduction) and N2-fixing populations was evaluated in rice soils under two water regimes. N2fixation was less pronounced in two saline soils and in a normal non-saline soil amended with salt mixture (salinity level of 4 and 30 dS/m) than in a non-saline soil under flooded and nonflooded conditions. Flooded soils amended with rice straw showed higher N2-fixing activity than the non-flooded soils at all salinity levels used in the study. Leaching the saline soil improved N2fixation. An increase in the soil salinity led to a decrease in the populations of at least three groups of N2-fixing micro-organisms. The population density of anaerobic N2fixers and Azospirillum in a saline soil increased considerably after leaching or after addition of rice straw. Azotobacter populations were little affected by the salinity levels used in this study. Results indicate that soil amelioration for salinity with leaching and organic matter addition would improve the implicated microbial populations and N2fixation in salt-affected rice soils.
Predicting sodification of calcium-saturated soil columns on leaching with sodic waters
Authors: Siyag R. S. , Lamba M. S. , Pal Raj , Poonia S. R. 
Published: March 2009

SummaryDepth accumulation of exchangeable Na+ was measured in Ca-saturated sandy loam soil columns (length 50 cm; diameter 5 cm) after percolating 500, 1000, 1500 and 2000 ml of 013 M Na+, as NaCl, NaHCO3, Na2SO4 and Na2CO3 solutions. The values of exchangeable sodium percentage (ESP) increased gradually with the increase in the volumes of the solution percolated. Two conceptual layer models, based on whether solutions were added to the topmost soil layer in one lot (M-I) or in splits equal to the saturation deficit (M-II), were used to predict the depth distribution of ESP of soil. The chemical processes considered in the models were the formation of ion pairs and the exchange equilibria of Na+ and Ca2+. The predicted values of ESP were considerably higher for model M-II than model M-I. The consideration of ion-pair formation and the accompanying anion had only negligible effect on the predicted ESP. The model M-II over-predicted the experimental ESP throughout the soil columns, whereas the model M-I under-predicted it for the upper layer(s) and over-predicted for the lower layers. On the basis of average ESP of the whole columns, the less realistic model M-I predicted experimental results better than model M-II. This was attributed to the presence of mobile and immobile zones for the flowing solutions.
The effect of level and type of concentrate and type of conserved forage on dry matter intake and milk production of lactating dairy cows
Authors: Phipps R. H. , Weller R. F. , Elliott R. J. , Sutton J. D. 
Published: March 2009

SummaryBetween weeks 3 and 16 of lactation 191 British Friesians received a basal ration ad libitum of either grass silage (GS), grass and maize silage (GS/MS) blended in a ratio of 1:2 or grass silage and 4% NaOH-treated barley straw (GS/TS) blended in a 4:1 ratio. The grass silage, which was not well preserved, had an estimated metabolizable energy (ME) content of 9–9 MJ/kg D.M., while corresponding values for the GS/MS and GS/TS mixtures were 106 and 9–5 MJ/kg D.M., respectively. A conventional concentrate (CC) based on barley and soyabean meal was fed at three levels (9, 6 and 3 kg fresh weight/day). Although the 9 kg level was only used in conjunction with GS, the two lower levels were fed with all three forage types. Concentrate composition was also varied at the 6 and 3 kg levels by replacing, in each case, 2 kg CC with a special concentrate (SC) which, in addition to barley, wheat and soyabean meal contained, on an air-dry basis, 25 % fishmeal and 25 % protected fat in the form of Megalac
Studies on the effect of green manuring in nitrogen economy in a rice–wheat rotation using a 15N technique
Authors: Goswami N. N. , Prasad R. , Sarkar M. C. , Singh S. 
Published: March 2009

SummaryA field experiment using 15N was carried out at the Indian Agricultural Research Institute, New Delhi during the crop year 1985–1986 to investigate the possible economy in fertilizer nitrogen applied to rice and succeeding wheat by growing a summer leguminous green manure (Sesbania aculeata) and incorporating it in soil before transplanting rice. Grain and straw yields of rice with 60 kg N/ha after green manuring were slightly greater than with 120 kg N/ha after summer fallow. Thus summer green manuring can lead to an economy of 60 kg N/ha in rice. 15N analysis showed that green manuring contributed 4·7–5·6% N of the total taken up by rice and 1·9–4·8% of that taken up by the succeeding wheat, depending upon the rate of fertilizer N applied to rice.15N analysis showed that at 60 kg N/ha applied to rice, 35·4% was recovered by rice, 41% by the succeeding wheat and 16·7% was left in the 0–45 cm soil layer after summer fallow; after green manuring 32·8% N was recovered by rice, 3·0% by succeeding wheat and 22·6% was left in the soil. Thus 56·2 and 58·4% of applied N could be accounted for after summer fallow and green manuring, respectively. At 120 kg N/ha about 60–61% of applied N could be accounted for. Thus about 40–44% of N applied to rice was lost by the various loss mechanisms operating in rice fields.
The effects of fertilizers on the bulking of Majestic potatoes
Authors: Hanley F. , Jarvis R. H. , Ridgman W. J. 
Published: March 2009

1. Four experiments designed to investigate the effect of fertilizers on the rate of bulking of Majestic potatoes are described and the results discussed.2. Irrespective of fertilizer application yield increased until the haulm died and then decreased slightly.3. Sulphate of ammonia increased the yield by increasing the number of tubers and increasing the yield in all size-grades. Thus its effect was seen throughout the season, no matter what grades yield was based on. It also increased dry-matter percentage.
Carbohydrate levels and regrowth in perennial rye-grass
Authors: Davies Alison 
Published: March 2009

In a series of experiments in which variations in the level of carbohydrates in the plant have been brought about by means of short-term exposures to darkness and raised temperatures, it has been shown that:1. The yield of leaf material after cutting is affected by pretreatments. This effect seems to be at least partly associated with the level of carbohydrates present in the stubble at the time of cutting.2. The rate of growth of the plants is independent of the pretreatments imposed once growth is fully established.
Unsaturated water transmission characteristics of soils in relation to texture, aggregate size and initial moisture content
Authors: Mundra M. C. , Pal Raj , Siyag R. S. , Poonia S. R. 
Published: March 2009

SummaryTo study the effect of soil texture, aggregate size and initial moisture content on soil water diffusivity, D(θ), and unsaturated hydraulic conductivity, K(θ), horizontal absorption experiments were conducted on samples of loamy sand, sandy loam and clay–loam soils as well as on artificially prepared water-stable aggregates of a clay–loam sample (sizes 0.·25–0–25, 0·25–0·5, 0·5–1, 1–2, and 2–4 mm). For comparable moisture contents, D(θ) followed the order loamy sand > sandy loam > clay–loam. The effect of initial moisture content on D(θ) varied with soil texture. K(θ), which was evaluated using D(θ) for air-dry initial moisture content and the slopes of the water retention curves, also varied with soil texture.The D(θ) function for air-dry initial moisture content increased with the decrease in aggregate size, the increase being more pronounced below a size of 1 mm. Values of D(θ) obtained from initially airdry soil and at 10% of saturation moisture content did not differ greatly from one another. The K(θ) function was almost the same for aggregate sizes 1–2 and 2–4 mm. In the size ranges of < 1 mm, K(θ) increased with the decrease in aggregate size. The particle/aggregate size range of 0·1–0·5 mm was the most conducive to unsaturated water flow.
The effects of grassland management on nitrogen losses from grazed swards through ammonia volatilization; the relationship to excretal N returns from cattle
Authors: Jarvis S. C. , Hatch D. J. , Roberts Daphne H. 
Published: March 2009

SummaryAmmonia (NH3)-N fluxes from three swards, grazed by cattle and with different N managements, were measured using the mass balance micrometeorological method after a 7-day grazing period in the spring of 2 years. At the same time the impact of the sward managements on N returns in dung and urine was examined in housed animals and the effects of the changes in excreted returns on NH3-N losses examined. The treatments were ryegrass swards receiving either 420 or 210 kg N/ha per year, and a mixed ryegrass/white clover sward receiving no mineral N. There was little difference in the faecal N returns between treatments but there were differences in the N returned in urine, thus 74, 60 and 56% of the excreted returns from 420 N, 210 N or grass/clover treatments, respectively, were in urine. The fluxes of NH3-N from the grazed swards were greatest whilst the animals were present and there were large differences between treatments, the ratio of total NH3losses from 420 N grass to those from 210 N grass and grass/lover being 7·8:1. The NH3-N losses were equivalent (i) to 12,5 and 7 % of the urinary N returns to 420 N, 210 N grass and grass/clover swards, or alternatively (ii) to 9 and 3% of the fertilizer addition to 420 and 210 N swards and 3% of the estimated rate of N2fixation in the grass/clover sward. Throughout the investigation there was little difference between the effects with the 210 N grass swards and those with grass/clover.
Evaluation of winter hardiness in Romanian introductions of Lolium perenne
Authors: Tcacenco F. A. , Eagles C. F. , Tyler B. F. 
Published: March 2009

SummaryCharacterization of accessions of Lolium perenne collected in Romania, using naturally hardened tillers in an artificial freezing test, is described. Accessions showed contrasting hardening response to variation in the winter environment at Aberystwyth. Cold tolerance of the accessions, measured as lethal temperature for 50% of the tillers (LT50), was positively correlated with the mean temperature of the coldest month at the sites of origin and with persistence in swards after three winters. Superior populations were identified within this collection and are being used as a source of winter hardiness in a breeding programme.The role of temperature and irradiance in the contrasting hardening responses of three accessions was investigated in controlled-environment studies with seedlings.The advantages of environmental simulation techniques for characterization of genetic resources are discussed.
The effects of diets deficient in phosphorus, phosphorus and vitamin D, or calcium, on the skeleton and teeth of the growing sheep III. The composition and structure of the teeth. III. The composition and structure of the teeth
Authors: McRoberts M. R. , Hill R. , Dalgarno A. C. 
Published: March 2009

1. The teeth of sheep that had been fed from 6 months of age for 12 months on diets low in calcium or in phosphorus and vitamin D content were compared with those of similar animals fed a control diet.2. The low calcium diet depressed the development of both dentine and enamel but had a greater effect on enamel than dentine, while the low phosphorus and vitamin D diet depressed dentine development slightly and had practically no effect on enamel.3. The percentages of ash of the dentine and enamel were not significantly affected by the diets fed.
Effects of autumn harvest date on the performance of white clover/grass mixtures in Nova Scotia
Authors: Fraser J. , Sutherland K. , Martin R. C. 
Published: March 2009

SUMMARYWhite clover (Trifolium repens L.) is well adapted to the cool moist climate of Atlantic Canada, where it improves digestibility and protein content in pastures, but little is known about its role in pasture stockpiled for autumn grazing in this region. The objectives of this study were to determine the effect of autumn harvest dates on dry matter yield and clover content in herbage mixtures. Two experiments conducted in Nova Scotia between 1985 and 1991 on two different soil types showed that the effects of autumn harvest dates were inconsistent from year to year. Herbage growth rates ranged from 11 to 41 kg/ha per day between early September and mid-October. Clover content was generally lower in August–early September than in November harvests and declined in subsequent years irrespective of harvest date or forage species. Kersey White and Sonja white clovers were the highest yielding cultivars. Crude protein declined in late autumn harvests whereas acid detergent fibre tended to increase, and there were differences between years. Forage quality was significantly better in tall fescue (Festuca arundinacea Schreb.) than orchardgrass (Dactylis glomerata L.)/white clover mixtures.
Soil properties and mineralogy in relation to land use on a sedimentary toposequence in south-eastern Nigeria
Authors: Eshett E. T. , Omueti J. A. I. , Juo A. S. R. 
Published: March 2009

SummaryThe mineralogy of the clay fraction (<2 μm) of nine soil samples representing three physiographic positions of a toposequence in Ochon, south-eastern Nigeria, was determined by transmission electron microscopy and X-ray diffraction.Soils in the crest and middle slopes (pedons TE1 and TE2, respectively) of the toposequence, formed over fine-grained sandstone, were coarse-textured, well-drained and acidic and had low effective cation exchange capacity and percentage base saturation. Kaolinite, mica, quartz, goethite and gibbsite were the principal minerals identified in the clay fraction of these soils. Soils in the valley bottom (pedon TE3) formed over arenaceous shale were, on the other hand, fine-textured, poorly drained and weakly acidic with higher cation exchange capacity and percentage base saturation. Their clay fraction mineralogy was similar to that of the well-drained upland soils but additionally included feldspar and smectite/vermiculite mixed layer minerals.Mixed cropping of yam, cassava, maize and other annuals under traditional methods was carried out on the drier, well-drained crest and upper slopes while sole cropping of lowland rice occurred in the poorly drained, more fertile valley-bottom site. The valley-bottom soils show greater potential for improvement in agricultural productivity under good management than the upland soils.
Gene for resistance to bean common mosaic virus in cvs Seafarer and Aurora of Phaseolus vulgaris
Authors: Innes N. L. , Walkey D. G. A. 
Published: March 2009

SUMMARYResistance to bean common mosaic virus in the cultivars Seafarer and Aurora from the U.S.A. is controlled by the dominant gene I originally found in the cv. Corbett Refugee.
The utilization of phosphorus and nitrogen in wheat offal by growing pigs
Authors: Frape D. L. , Wayman B. J. , Tuck Mary G. 
Published: March 2009

SUMMARYTwo experiments with growing pigs grouped in pens and three with growing pigs kept in metabolism crates were undertaken in order to determine young growing pigs'dietary requirement for phosphorus of vegetable origin, the relative potency and true digestibility of that source and the effect of dietary Ca concentration on its utilization. Much of the P was contained in wheat offal, and of this 900 g/kg total P was phytin-P.In the first two experiments the responses to vegetable P were measured by pig live-weight gain, gain: feed ratio, several conventional carcass measurements and the weight, length and density, and the ash, Ca and P contents of the fourth left metacarpal, and also by the alkaline phosphatase activity of blood serum. No significant differences were found between treatments in terms of body-weight gain, gain: feed ratio, or the commercially important carcass characteristics. The requirement of pork pigs for P was measured by bone and serum enzyme characteristics when all the dietary P was of plant origin, apart from 0·3 g P/kg from casein. Under the conditions of this experiment this P requirement appeared to be met when the diet contained 5–6 g P/kg. The potency of vegetable P in Expts 1 and 2 and of wheat offal P in Expt 3 relative to feed grade dicalcium phosphate was 0·77, equivalent to a net retention of 0·4–0·5 as a proportion of that consumed estimated from growth and digestibility measurements. A true digestibility coefficient of 0·53±0·01 for wheat offal P was obtained in Expts 4 and 5. The effect of variation in dietary N and energy, associated with variation in dietary offal concentration, on the reliability of the potency estimates is discussed.Increasing dietary Ca concentration caused a slight decrease in the digestion of wheat offal-P. The soaking of wheat offal in water for an average of 11 h before feeding increased P digestion in one of two experiments.In vitroevidence indicated that soaking initiated the hydrolysis of insoluble P compounds.
The relationship between mean temperature and accumulated temperature totals for maize in the central lowlands of England
Authors: Bunting E. S. 
Published: March 2009

SUMMARYIn northern areas of maize production in Europe and America, increasing use is being made of the association between accumulated temperature and stage of crop development. Temperature is accumulated either in terms of day-degrees above a given base temperature, taken to be 10 °CC in the U.K., or in terms of developmental units (‘Ontario Units’). Formulae for obtaining the daily contribution from recorded maximum and minimum air temperatures are available for compiling accumulated temperature totals for each of these methods, but the processing of long series of data is tedious, even with the assistance of computer programs. Results are presented from several locations in the central lowlands of England to suggest that very close approximations to the true monthly or seasonal totals can be obtained from the regression relations with corresponding mean monthly or seasonal temperatures.For the sites considered the regression equations were sufficiently close to make joint, ‘regional’, regression equations appropriate. It is believed that the results will be applicable to other areas of England, and that the methods suggested might provide a suitable basis for supplementing the information available on accumulated temperatures elsewhere in northern Europe.
Effect of N, P and K fertilizers on the availability of native and applied manganese to wheat
Authors: Mishra B. , Tripathi B. R. 
Published: March 2009

SUMMARYThe influence of three rates of each of N, P and K fertilizers on the availability of native and applied Mn to wheat was studied in a field experiment on an alluvial soil of the Indo-Gangetic plain. Increasing dressings of N as ammonium sulphate resulted in consistently higher yields and Mn uptake by the crop. Concentration of Mn in the grain increased with increasing N dressings when native Mn and Mn fertilizer supplied this nutrient but it was unaffected inplants sprayed with Mn. Adding P as superphosphate tended to lower the concentration of Mn in the grain when relying on native or applied Mn but it significantly enhanced the crop yield and total Mn uptake. Applying K as muriate of potash slightly depressed Mn uptake by plants. Potassium had a more pronounced effect in the absence of P fertilizer. The concentration of Mn in thestraw was not significantly affected by N, P and K fertilization.
The response of pastures in Northern Ireland to N, P and K fertilizers and to animal slurries: I. Effects on dry-matter yield
Authors: Adams S. N. 
Published: March 2009

SUMMARYSixteen factorial experiments made from 1969 to 1971 on Northern Ireland pastures measured effects on yield of 0, 180 or 360 kg of N, 0, 30 or 60 kg of P and 0, 150 or 300 kg of K/ha/year both with and without 138,000 1 of slurry/ha.Without slurry, pasture yield was almost always substantially increased by nitrogen, slightly by potassium and hardly at all by phosphorus. There was a slight positive interaction between nitrogen and potassium, but no other interactions. Response to nitrogen was not linear and therefore was lower than has been obtained in many British trials.Slurry sharply reduced response to nitrogen and virtually eliminated response to phosphorus and potassium. The NH4-nitrogen content of slurry gave an adequate measure of its effect on pasture yield. The nitrogen, phosphorus and potassium contents of the most concentrated slurries were 15, 29 and 36 times respectively those of the most dilute batches. Hence considerable imprecision is brought into a fertilizer programme when slurry is applied.As manuring on individual fields can never be precise, the fertilizer phosphorus and potassium needed for grassland is best assessed by considering the farm as a whole. A nutrient balance can show if the farming system is gaining or losing phosphorus and potassium. The amounts of fertilizer phosphorus and potassium needed are those which cover any deficits on the farm as a whole.