bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen Fixation by Irrigated Berseem Clover versus Soil Nitrogen Supply
Authors: Williams W. A. , Graves W. L. , Cassman K. G. 
Published: April 2008

AbstractNitrogen fixation was estimated by the difference method for two cultivars of berseem clover (Trifohum alexandrinum L.), using annual ryegrass (Lolium multiflorum Lam.) as the control in field trials from 1983 to 1988. Five or six cuttings were obtained each year under supplemental irrigation, and dry matter production and uptake of nitrogen into harvested forage were measured.Estimates of nitrogen fixation by berseem clover ranged from 272 to 400 kg N/ha depending on year and cultivar, while plant N derived from soil (based on N uptake by the ryegrass) ranged from 50 to 235 kg N/ha. Graphs of nitrogen fixed versus available soil nitrogen had a reverse linear‐plateau shape with a plateau at lower soil nitrogen levels that broke sharply in a linear decline as available soil N surpassed a minimum threshold. Such a two‐phase response suggests that nitrogen fixation by the clover was limited by soil N supply above this threshold and by other limiting factors at low soil N levels, perhaps genetic traits controlling carbon assimilation or environmental limitations other than nitrogen. Seasonal nitrogen process patterns showed abundant nitrogen fixation by the clover after it had depleted most of the soil nitrogen supply.
Sward Height and a Capacitance Probe for Estimating Herbage Mass
Authors: Bryan W. B. , Thayne W. V. , Prigge E. C. 
Published: April 2008

AbstractEstimation of herbage mass is essential in pasture research and in making practical grazing management decisions. Sward height and a capacitance probe were evaluated as non‐destructive measures of herbage mass at seven dates from April 16 to July 30 on continuously grazed predominantly Kentucky bluegrass (Poa pratensis L.) pasture. Paddocks were 1 ha in size and were stocked at 3, 4 or 5 steers ha−1 (average initial weight 312 kg). Four to six, sampling points were located randomly in each paddock at each date. Sward height was measured with a ruler, the vegetation in a 0.2 nr area visually designated “high” or “low” according to legume percentage, ten readings using a single capacitance probe were made and the herbage clipped. Paired data with clipped dry weight as dependent variable and height and/or the average corrected probe reading as covariates were analyzed statistically. The relationship between clipped dry weight and nondestructive measures of herbage mass was found to be linear. There was a small effect of sampling date in Spring on the relationship between destructive and non‐destructive measures of herbage mass, but each of the measures, including herbage mass predicted from probe and height measurements, resulted in the same inferences being made about differences between treatments. Neither stocking rate nor small differences in percentage legume affected the relationship. Thus, sward height and capacitance probe show promise as nondestructive measures of pasture herbage mass.
Effect of Seed Size on Germination and Seedling Growth in Greengram (Vigna radiata L. Wilczek) and Blackgram (Vigna mungo L. Hepper) Cultivars
Authors: Chandra Babu R. , Muralidharan V. , Seetha Rani M. , Nagarajan M. , Sree Rangasamy S. R. , Pallikonda Perumal R. K. 
Published: April 2008

AbstractThe effect of seed size on germination and seedling growth was assessed using cultivars of greengram and blackgram. Significant positive correlation was noticed between seed size and germination, seedling height, root length, primary leaf size and seedling weight. The possible advantages of choosing cultivars with heavier seeds for attaining better crop stand especially under rainfed situation are discussed.
15N Studies of the Behavior of Fertilizer Nitrogen in Three Different Soils (Lysimeter Trials)
Authors: Dressel J. , Jung J. 
Published: April 2008

AbstractA lysimeter trial is described in which the fate of 15N was monitored in a sand, loam and clay soil by using it over a period of 6 years. The following results were obtained.1. The uptake of fertilizer nitrogen by plants, determined by using 15N, is lower than by using the conventional method (“difference method”). Nitrate 15N is better utilized by the plants than is ammonium 15N. The total nitrogen uptake only gives hints of these differences.2. The extent to which plants utilize fertilizer 15N is between 38 and 58%; in the case of the method of differences this figure is between 48 and 68%.3. Plants remove more nitrogen from the soil when fertilizer N is applied than when without fertilization. The influence of these two nutrient forms is of subordinate significance.4. After a trial period of six years between 26 and 54 % of the fertilizer 15N remains in the soil. The resulting sequences are clay > loam > sand > and ammonium > nitrate.5. The immobilization of the fertilizer 15N is most pronounced in the first four years but then decreased considerably; in the case of the sandy soil it is then even slightly regressive.6. The biggest part of the 15N is deposited in the uppermost layer of the soil. The amount of 15N in the deeper layers is diminished appreciably. The type of soil has a greater influence than the form of nitrogen.7. If the amount of fertilizer N left in the soil is compared with the N losses from the soil's reservoir (plants' uptake, leaching) there is a negative balance for the soil nitrogen which mainly is determined by the type of soil.
Comparisons of Methods of Estimating the Seed Filling Period in Soybeans*
Authors: Pfeiffer T. W. , Suryati D. 
Published: April 2008

AbstractAn experiment was conducted at Lexington, K.Y., USA (38° N latitude) utilizing 18 soybean (Glycine max [L.] Merr.) genotypes in three stem termination groups (determinate, indeterminate, and segregating) to compare eight methods of estimating seed filling period in terms of 1) ability to differentiate among genotypes, 2) lack of bias towards any stem termination type, 3) ease of measurement, and 4) consistency across environments. Growth stage estimates R1 to R8, R4 to R7, R5 to R7 and the reproductive period duration (estimate of the time period of the linear increase in harvest index) detected significant differences among the seed tilling periods of the genotypes. Significant stem termination group measurement method interactions were present, but because the indeterminate stem termination group had a shorter seed filling period than the other two groups for most methods, we were unable to evaluate bias towards stem termination type. The growth stage methods required 4x to 10x less time for data collection than the effective tilling period and reproductive period duration methods. Only the R4 to R7 and R5 to R7 growth stage estimates had significant rank correlation coefficients among genotypes across years. From this and previously published evidence we recommend using the R5 to R7 estimate of seed filling period following the separation of genotypes into stem termination classes for the selection of soybean genotypes based on seed filling period duration.
Soybean Genotypic Variation for Nitrogen Fixation
Authors: Reddy G. B. , Faza Alexandra 
Published: April 2008

AbstractEighteen soybean (Glycine max [L.] Merr) cultivars from maturity groups V and VI were screened with two Bradyrhizobium japonicum strains (USDA 110 and TAL 378) in the greenhouse to determine N2 fixation (C2H2: reduction) rates. Antibiotic resistant markers were used for observing nodule occupancy. Cultivars L.‐76‐0132, PI 159319, Hoberland, Lee, PI 22173 and Centennial showed high nitrogenase activity of 6.25, 5.54, 17.43, 4.73, 6.94, and 4.81 μM C2H4/Pl/hr, respectively. Cultivars PI417419, PI 230978, Ogden, and FC 31665 showed low nitrogenase activity of 1.51, 0.80, 0.62 and 0.94 μM C2H4/Pl/hr, respectively. The data from this screening experiment suggest that the N2 fixation varied among genotypes and all the nodules were occupied by the inoculated strains only. Rhizobial strain effect was observed among soybean cultivars (MGVI).
Chemical Composition and In Vitro Dry Matter and Organic Matter Digestibility of Triticale Forage
Authors: Fearon A. L. , Felix A. , Sapra V. T. 
Published: April 2008

AbstractTriticale (X Triticosecale Wittmack) cultivars Council and Morrison were planted in mid‐September (early planting) and mid‐October (late planting) in 1984 at the Alabama A &: M University‐experiment station for studying organic matter digestibility. The plants were harvested at the tillering, milk and dough stages and samples were subjected to proximate analyses and in vitro digestibility tests. A 1,100 lb Hereford steer fitted with a permanent ruminal fistula was used as the rumen fluid donor. In vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) were determined by Moore's modification of the two‐stage digestion technique of Tilly and Terry (1963). Triticale cultivar Council was comparable to Morrison for phosphorus (P), dry matter (DM), ceil wall content, IVDMD and IVOMD. Crude protein (CP) and ash content were significantly higher for Morrison than for Council, while gross energy (GE) was significantly higher for Council than for Morrison. Both early and late plantings showed similar levels of DM, GE, P and cell wall constituents. However, CP and ash content were higher for early planting than late planting. The tillering stage was consistently higher than the milk or dough stages for CP, ash, P, calcium (Ca), IVDMD and IVOMD. The results indicate that the milk stage was superior to the tillering or dough stages in DM and cell wall content. Results from this study showed no significant differences in digestibilities for two triticale cultivars and planting dates. Based on the higher DM content at the milk stage, it seems that milk stage in triticale would be more acceptable as a forage than the tillering or dough stage.
On the Variability of Harvest Indices
Authors: Hühn M. 
Published: April 2008

AbstractThe harvest index Z is defined, for example for cereals, as the ratio between grain yield X and biological yield Y: Z = X/Y. For many purposes the variance of Z is of major interest. In this paper several approximations for this variance are derived and their accuracy was investigated. These explicit formulae depend on some characteristics (means, variances or coefficients of variation, covariances or correlations) of the component variables grain yield X and biological yield Y. It is shown that for most practical applications the approximation v2z = v2x + v2y ‐ 2rvxvy provides a sufficient accuracy for numerical calculations (vx vy and vz are the coefficients of variation for grain yield X, biological yield Y and harvest index Z and r denotes the correlation coefficient between X and Y). Some conclusions on the relations between vx, vy and vz are derived.Finally, all the theoretical investigations and results are demonstrated and applied to a numerical example of winter‐rapeseed data.
Nitrogen Distribution and Dry Matter Accumulation in Oilseed Rape (Brassica napus L.) as Influenced by N Nutrition
Authors: Ogunlela V. B. , Kullmann A. , Geisler G. 
Published: April 2008

AbstractA greenhouse experiment was conducted to study N distribution and dry matter accumulation in oilseed rape (Brassica napus L. cv. Callypso) in relation to N supply. Three levels of N supply (30, 100 or 170 ppm N) were tested as treatments. Stem and leaf dry weights increased at higher N fertility up to 170 ppm N but root dry weight did not respond to N. Dry matter yield during the vegetative phase was seriously depressed by N deficiency. Most of the plant dry matter was accumulated in the lower segments of the stem and roots. Dry weights of stem and axillary branches increased significantly as N supply increased up to 100 ppm N. Although hull dry weight increased with N supply up to 100 ppm N, seed dry weight did not respond to N. High root N concentration was maintained at 100 or 170 ppm N; but declined as plants advanced in age. N content of leaf and stem also declined with time. Leaf growth was particularly responsive to N fertility and N was mobilised from the older to the younger leaves over time. Nitrogen content of hulls and seeds increased significantly with N supply but N was translocated from the vegetative into the generative organs or from older into younger tissues during pod development. There is need for proper N fertility management in order to achieve successful rape production.
Cassava and Maize Intercropping Systems ‐ The Effects of Varieties and Plant Populations
Authors: Ezumah H. C. , Lawson T. L. 
Published: April 2008

AbstractMaize dominated cassava irrespective of cassava or maize growth habit and the optimum maize population giving the highest production based on relative yield total or land equivalent ratio varied with maize variety in a tropical Alfisol at Ibadan, transition humid/subhumid zone in West Africa. The sparsely vegetative, early maize supported higher intercrop maize population (up to 80,000 ha−1) than the late maturing, highly vegetative TZSRW. Because there is a compensatory relationship in the yields of the two crop components, the choice of an appropriate crop type and maize population in cassava + maize intercrop system will depend on the relative economic importance of each crop component.
Photosynthetic Response of Wheat to Soil Water Deficits in the Tropics
Authors: Brar G. S. , Kar S. , Singh N. T. 
Published: April 2008

AbstractThe changes in photosynthetic rate and translocation of photosynthates in winter wheat (Triticum Aestivum L.) grown in lysimeters were studied, in response to periodic soil water deficit during late tillering and flowering stages. Soil water deficits were imposed to previously nonstressed plants during late tillering and flowering states. Timing of irrigation was scheduled according to the ratio between irrigation water applied and cumulative pan evaporation (IW/CPE) of 0.75 (low deficit), and 0.5 (moderate deficit), as well as by suspending irrigations after crown root initiation stage (severe deficit). To determine the rate of photosynthesis, a short radioactive pulse of 14CO2 with 300 ppm concentration was given to second leaf from the top at tillering, and to the flag leaf at flowering stages for 20 second exposure time. The translocation of photosynthates was estimated by scanning 14C activity in different plant parts. In late tillering the midday Photosynthetic rate (PR) was significantly 3 mg CO2 dm−2 h−1 lower under low water deficit (WD1) than under zero water deficit (WD0). Under higher stress conditions, soil water acted as a limiting factor to keep the rate from rising above 13.2 during stress at late tillering (WD2), 14.5 flowering (WD4), and 10.0 mg CO2 dm−2 h−1 for stress at both the growth stages (WD5), respectively. The difference in daily accumulated photosynthesis (8 h), between stressed and nonstressed were 15, 40, 42, and 77 mg CO2 dm−2 h−1 respectively at WD1 WD2, WD4, and WD5. The retention of 14C in flag leaf decreased considerably after 24 hours of exposure time when the labelled assimilates were translocated in bulk to the ear head. Under stressed condition a general trend was observed for upward translocation of assimilates towards the ear, even from the stem and root. The percent 14C activity observed in ear after 24 hours was greatest in severely stressed plants. The photosynthetic rate is reasonable predicted by midday LDR and surface moisture.
Ein Beitrag zur Stickstoffwirkung nach unterschiedlichen Verfahren stabilisierter Klärschlämme*
Authors: Schkrer H. W. , Steffens Do. 
Published: April 2008

Abstract A distribution to the availability of the nitrogen in sewage sludges stabilized with different processes In two pot experiments the availability of the nitrogen in sewage sludges stabilized with different processes was investigated. Further it was examined whether the Quantofix‐N‐Volumeter (method for rapid determination of ammonia in slurries) is able to determine the plant available nitrogen in sewage sludge.The following results were obtained:In the experiment where same amounts of total N were applied as sewage sludge a highly significant correlation existed between the amount of NH4‐N applied and the N uptake of the plants.When equal amounts of NH4‐N were applied the N uptake was lowest with the sewage sludges with a high relative part of NH4‐N of the total N (thermophile‐aerob; mesophile‐anaerob). However the reason for this result was not only the lower application rate of total N with these sewage sludges but also the lower efficiency of the organically bound nitrogen.A very highly significant correlation existed between the application rate of organically bound nitrogen and the N uptake.The values of nitrogen in sewage sludges measured by the rapid method gave information about the plant available nitrogen in the year of application.A close quantitative agreement existed between the available nitrogen determined with the rapid method and the values calculated with the formula of Furrer and Bolliger (1978).
Radio Tracer Studies on P Use Efficiency in a Rice Based Cropping System
Authors: Sreekantan Lekha , Palaniappan SP. 
Published: April 2008

AbstractTracer studies using 32P labelled superphosphate and rock phosphate were conducted in microplots in a field experiment on rice‐rice‐greengram cropping system. The trial revealed that in all the rice crops studied, P uptake and P use efficiency were higher in superphosphate treated plots than in rock phosphate applied ones. P uptake was improved with organic manuring through application of green manure or crop residues like long rice stubbles. While superphosphate performed well either with or without organic manuring, rock phosphate performed fairly well only with organic manuring. Fairly good P use efficiency could be obtained in the system when green manuring and rock phosphate application in the first crop was followed by superphosphate and long stubble incorporation in the second crop. Apparent recovery values also showed nearly the same results. But tracer studies were found to be definitely superior in the evaluation of fertilizers.
Zum Einfluß von Saatzeiten, Saatstärken und Sorten auf agronomische Merkmale von Winterweizen in einem System mit geringer Betriebsmittelzufuhr von außen
Authors: Stöppler H. , Kölsch E. , Vogtmann H. 
Published: April 2008

Abstract The influence of sowing date, seed rate, and variety on agricultural characteristics of winter wheat in a low external input system Growth conditions of winter wheat in agricultural low external input systems, e.g. ecological agriculture, are very different compared to conventional agriculture (mineral nutrition, impact of diseases, competition of weeds). In 1986, 1987, and 1988 the influence of sowing date and seed rate on crop development and grain production was studied with two varieties of winter wheat in field experiments in Northern Hessia.Drilling after the first decade of October decreases grain yield of both varieties significantly. The decrease was due to poor emergence, low plant densities, and low grain weights. Tillering could not compensate low plant densities, presumably because of low mineralization of nutrients in cold soils during respective growth stages.Variation of seed rate (350, 500, and 650 viable seeds/m2) had little influence on grain yield. Low plant densities and low numbers of ears per nr after sowing in the end of October could not be improved satisfactorily by increased seed rates.The ability of varieties of winter wheat to compensate unfavourable growth conditions due to “late” sowing varies considerably. Cultivars which are able to develop a high plant density seem to be more suitable for delayed sowing dates, as compared to varieties which own a high grain weight.Further investigations concerning wheat production are needed to optimize agricultural low external input systems. Especially sandy soils with quick response to increased ambient temperature, and sites with favourable growth conditions in late autumn and early spring should be considered.
Soybean‐Rhizobium Combination for Tolerance to Low P‐High Aluminum
Authors: Taylor R. W. , Sistani K. R. , Patel S. 
Published: April 2008

AbstractTwo greenhouse experiments were conducted to evaluate the performance of selected soybean‐Bradyrhizobium combinations in a soil having low P‐high aluminum stresses under controlled conditions. Growth parameters such as plant height, nodule numbers, dry weight, nitrogenase activity and seed yield were used as an index. Three selected acid (low P‐high Al) tolerant (Essex, Tracy and Bedford) and three sensitive (Peking, Hill and McNair 600) soybean (Glycine max) varieties were sown in each pot. Three of the most tolerant strains of Bradyrhizobium (USDA 6, 110, 122), a mixture of these strains, and a commercial inoculant (Nitragin) were used to inoculate the Hartselle sandy loam soil. The results indicated that soil acidity significantly affected the soybean Bradyrhizobium symbiosis. The combination of variety Tracy plus Nitragin (mixed‐strain) produced the highest and variety Peking plus mix‐strain Nitragin the lowest plant height at all pH levels. Plants inoculated with Nitragin had higher shoot dry weight and seed yields. Variety Essex in combination with Nitragin produced the highest seed yields at all pH levels. Plants inoculated with Nitragin developed significantly more nodules than the other strains except for variety Peking. There was no significant difference in total nodule numbers between tolerant and sensitive soybean varieties at all soil pH levels except for Nitragin. Shoot total N did not increase by increasing the pH level or by using different variety‐strain combinations.
Fatty Acid Composition of Oil from Erucic Acid‐Free Summer Rape Seed (Brassica napus L.) in Relation to Nitrogen Nutrition and Raceme Position
Authors: Ogunlela V. B. , Kullmann A. , Geisler G. 
Published: April 2008

AbstractA greenhouse study was conducted to determine the effect of nitrogen supply (30, 100 or 170 ppm N) and raceme position on the fatty acid composition of oil extracted from erucic acid‐free summer rape seed (Brassica napus cv. Callypso). The seven fatty acids analyzed for include palmitic, palmitolcic, stearic, oleic, linoleic, linolemc, and eicosenoic acids; of which oleic (59.54–64.84 %) and palmitoleic (0.36–0.4 %) acids were the highest and lowest levels respectively. Generally, N nutrition influenced fatty acid pattern only to a little extent. Palmitic, palmitoleic and stearic acid levels were increased by 170 ppm N, depending on raceme position, but oleic and linolenic acids were unaffected. Similarly, 170 ppm N produced the highest fatty acid levels in seeds on the lower portions of racemes, with the exception of oleic acid. This was also true in the case of the upper portions of racemes, except that 30 ppm N produced the highest levels of oleic and linoleic acids in rape seeds. Under the optimum N supply level (i.e. 100 ppm N), position of raceme on the rape plant did not greatly influence the levels of different fatty acids in lipids.