bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Significance of Soil Burning (“Guie”) in Ethiopia with Special Regard to its Effects on the Agrestal Weed Flora
Authors: Pülschln L. , Koch W. 
Published: April 2008

AbstractSoil burning (“guie”) is a traditional farming practice in restricted areas of the Ethiopian highlands. Sods with adherent soil of grazed fallows are burnt which leads to comparatively high yields of the subsequent barley (Hordeum vulgare L.) crop. The weed species coverage and steadiness on burnt and unburnt spots of guie fields have been surveyed within the 1984/85 and 1985/86 growing periods using the Braun‐Blanquet cover‐abundance scale. On burnt spots weeds developed just about 1/3 of the cover on unburnt ones with a comparatively low share of monocotyledonous species. The total number of species collected was 103 (of 33 families) on unburnt spots and 77 on burnt ones. The average number of species/site was 39 and 26 respectively. The Poaceae, Asteraceae, Fabaceae and Caryophyllaceae were the most diverse families recorded with 27, 12, 10 and 6 species respectively. Species of highest steadiness like Ranunculus multifidus Forsk., Polygonum nepalense Meissn., Guizotia scabra (Vis.) Chiov. and Dicbondra repens J. R. & G. Forst. were significantly reduced in cover due to burning.
N‐Dynamik des Bodens, Ertragsbildung und Stickstoffentzug von Winterweizen bei unterschiedlicher Höhe und Verteilung der mineralischen N‐Düngung
Authors: Fischbeck G. , Dennert J. , Müller R. 
Published: April 2008

Abstract NO3 dynamics in the soil, yield formation and N uptake of winter wheat as influenced by dosage and distribution effects of N‐fertilizer application In a 4 year series of field trials carried out with 9 regimes of nitrogen fertilizer application at two trial sites with rather shallow top soil layers but large deviations in soil characteristics, grain yield varied between 50 dt/ ha and 120 dt/ha with nitrogen doses from 0–170 kg N/ha. Soil nitrogen supply for wheat grain formation on unfertilized plots reached 80 kg N/ha/year within the narrow range of 75–95 kg N/ha in different years at both sites which amounts to 1.5 % and 0.5 % of the highly different N‐content of the trial sites.The most successful nitrogen application regimes are characterized by modest fertilizer doses in early spring and the delay of supplemental fertilizer doses until growth stage EC 32. They resulted into modest NO) soil content from EC 29 to EC 32 and/or a noticable decrease of soil NO3 content during growth stage EC 30–32, which seems to be responsible for the development of only modest stand densities and reduced straw yield, while the delayed supplementation with nitrogen fertilizer overcompensated these effects mainly by increased grain numbers/ear and a remarkable improvement of harvest index.The contribution of soil borne nitrogen to kernel yield formation started to decrease with even low dosages of supplemental nitrogen fertilization with the exception of the highest yielding season 1987/88. Top levels of grain yield have been regularly obtained with supplemental nitrogen fertilizer dosages about 40 kg N/ha below grain yield nitrogen extraction if they were added within favorable application regimes.
Effect of Thermal Energy Intensity on Time and Rate of Nitrogen Accumulation by Maize (Zea mays L.)1
Authors: Olness A. , Benoit G. R. , Sickle K. van , Rinke Jana 
Published: April 2008

AbstractThe effect of thermal energy intensity (TEI) on the rate of nitrogen (N) accumulation by maize from a Hamerly clay loam soil (Aerie Calciaquoll) was examined with and without supplemental irrigation. Soil‐ and air‐TEI expressed as cumulative growing degree days (GDD) was determined from hourly temperature measurements taken within each plot at soil depths of 0.05‐, 0.15‐, and 0.3‐m and at a height of 1.2‐m above ground surface. A daily mean TEI (GDD per day) was calculated for each growth period. Estimates of time coefficient(s), k, in uni‐ and diphasic tanh[k(time)] functions, plotted against mean TEI for the periods; 1) planting to emergence, 2) emergence to eighth leaf, 3) eighth leaf to time(s) of maximum N accumulation rate, (t0), 4) planting to t0, 5) emergence to t0, 6) first diphasic maximum accumulation rate (t01) to 50 % silking, and 7) silking to second diphasic maximum accumulation rate t02 showed several linear relationships. Uniphasic time coefficients were modelled as functions of air‐TEI. The first diphasic time coefficient, k1 was modelled as a function of pre‐ and post‐emergent soil‐TEI. Attempts to model k2, the second time coefficient of the diphasic model were unsuccessful; however, this time coefficient was linearly related to TEI for the growth period ‘t01, to 50 % silking’ and curvilinearly related to k1.
Variability and Correlations in Grain Sorghum Genotypes (Sorghum bicolor [L.] Moench) Under Drought Conditions at Different Stages of Growth
Authors: Bakheit Bahy R. 
Published: April 2008

AbstractTwenty‐two genotypes of grain sorghum were grown under drought conditions by omitting one irrigation during stages of before flowering period, kernel filling period, and physiological maturity period at Assiut Univ. Farm in 1987 and 1988 seasons. The results obtained revealed that considerable variation existed among genotypes for all the studied traits. The most effective moisture stress treatment in reducing grain yield, panicle weight and plant height was during flowering stage. While 1000‐kernel weight was much affected by moisture stress during grain filling period. The genotype x year interaction (σ2gy) was large compared to genotype x irrigation treatment (σ2gl) indicated that genotypes responded differently when they were grown from year to year. The genotypic variance (σ2g) for all traits were large reflecting the importance of genetic variability. Both phenotypic and genotypic correlations among traits showed that plant height and 1000‐kernel weight were highly correlated with grain yield, while leaf area index was low associated with plant height.
Effect of Seedling Density and Shading Material on Germination and Early Growth of Tobacco (Nicotiana tabacum L.)
Authors: Sangakkara U. R. , Keerthi M. M. 
Published: April 2008

AbstractThe effect of four seedling densities developed soon after the emergence and two shading materials were studied in order to elucidate the response of seedling growth of tobacco. Germination and seedling emergence was better in beds under greycloth than under polythene. In contrast, shoot and root growth of tobacco seedlings was superior under polythene at all densities. This observation is attributed to optimal environmental conditions under polythene. The study also revealed that the highest shoot and root growth was at the lowest density. High plant densities hindered plant growth. Well developed plants were seen at the plant density of 165 plants per 0.1 m2 under polythene.
Effect of Gibberellic Acid on Seedling Growth and Carbohydrate Metabolism During Germination of Rice (Oryza sativa L. var. GR‐3) Under Saline Condition
Authors: Acharya Ujwala T. , Prakash L. , Prathapasenan G. 
Published: April 2008

AbstractInteractive effect of NaCl salinity and gibberellic acid (GA3) on seedling growth and carbohydrate metabolism of rice was studied for five days. NaCl reduced the embryo axis growth and the rate of hydrolysis of starch in the endosperm. Parallel to this reduced rate of reserve carbohydrate mobilization, a decreased activity of α‐amylase, β‐amylase, maltase and invertase was also found in the endosperm of sale stressed seeds. Presoaking treatment of seeds with GA3 (10 mg l−1), however, increased the growth of seedlings and enhanced the hydrolysis of starch as well as the activities of said enzymes. Electrophoretic analysis revealed that NaCl inhibits the synthesis of amylase isozymes which, in turn, reversed considerably by GA3 application.
Changes in Polyamine Titer in Rice Seedlings Following NaCl Salinity Stress
Authors: Katiyar Sadhana , Dubey R. S. 
Published: April 2008

AbstractSeedlings of four rice cultivars differing in salt tolerance were raised in sand cultures under increasing levels of NaCl salinity and metabolic levels of total polyamines, spermidine, spermine, agmatine and the diamine putrescine were determined in roots and shoots during 5‐20 days growth period. Salinity caused a remarkable increase in total polyamines level in rice seedlings. At similar level of salinity roots as well as shoots of salt sensitive cvs. Ratna and Jaya showed higher level of total polyamines than tolerants. Salinity of 14 dSm−1 NaCl caused more than 2 times polyamine level in shoots of sensitive cultivars compared to tolerants. Accumulation of polyamines was greater in salt stressed shoots than roots. In nonsalinized seedlings there appeared a gradual increase in putrescine level during 5 to 20 days growth period. Salt treatment caused sharp increase in putrescine level in all cultivars, however under similar level of salinization salt stressed seedlings of sensitive cultivars had higher putrescine level than tolerants. In nonsalinized seedlings of sensitive cultivars spermidine level increased gradually during 5 to 20 days growth period whereas a decline in the level was observed in seedlings of tolerant cultivars during this period. Higher level of salinity caused marked increase in spermidine level in sensitive cultivars. Specially during 5 to 10 days of growth salinity caused increase in spermine level in seedlings of sensitive cultivars. In all cultivars salt stressed seedlings had higher agmatine level compared to non‐stressed. Salinity led to greater accumulation of certain unidentified polyamines in seedlings of sensitive cultivars. Increased levels of total polyamines, putrescine, spermidine and unknown polyamines in rice seedlings under salinization suggest their possible role in combating the adverse effects of salinity stress.
Comments on the Calculation of Mean 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 total yield Y: Z = X/Y. For individual measurements xi of X and yi of Y the individual harvest index is calculated by zi= xi/yi. These individual measurements i are based on N different experimental units (single plants, random samples from plots or total plots).Mean harvest indices are commonly calculated either by or by where the means of X, Y and Z are denoted by x̄, ȳ and &#x007a;̄ respectively.Both approaches are, in general, different. But, in this paper it is shown that for most situations which may occur in the field of practical applications in agronomy and plant breeding both procedures will lead to nearly identical results. Only in some special situations the two results differ significantly. These conditions are investigated and explicitly given.Some explicit formulae (approximations) for the calculation of mean harvest indices are derived and discussed.Finally, all the theoretical investigations and results are demonstrated and applied to a numerical example of winter‐rapeseed data.
Variation in Seed Yield and Quality Characters of Four Spring Oil Rapeseed Cultivars as Influenced by Population Arrangements and Densities
Authors: Shrief S. A. , Shabana R. , Ibrahim A. F. , Geisler G. 
Published: April 2008

AbstractVariations of yield and quality characters of four spring oilseed rape cultivars (B. napus L.) arranged in 16 or 32 cm between drills and under three population densities (30, 60 and 90 plants/nr) were investigated in a split‐plot design with three replications in 1986 and 1987 in West Germany.Cultivar Callypso gave the highest seed and oil yields per plot and the highest seed index, harvest index and seed yield/main stem, per branches and per plant. Differences due to arrangements were significant in 1986 only, i.e., the value of a special plant distribution was more pronounced under unsuitable weather condition (as in 1986). With respect to the three population densities, most of the characters showed significantly higher values with 30 plants/nr. Only seed yield and oil yield per plot that showed 7.27% and 5.6% increase, respectively, under the highest population density (90 plants/nr) but the differences were insignificant.The highest oil content was obtained from cultivar Callypso and from the lowest population density. By contrast, higher protein content was obvious under higher population densities and the differences from the lowest density were significant in both years. Differences in fatty acid composition were not significant for the three main effects.
Effects of Root Zone Temperature on Root Activity of Two Potato (Solanum tuberosum L.) Clones with Different Adaptation to High Temperature
Authors: Sattelmacher B. , Marschner H. , Kühne R. 
Published: April 2008

AbstractUnder controlled environmental conditions, the effect of optimal (20 °C) and supraoptimal (30 °C) root‐zone temperature on root activity (respiration, soluble sugar content, ethylene release, nitrogen uptake and translocation) was studied in water culture with two potato clones differing in the heat tolerance of their root systems. Root respiration was little affected by raising temperature from 20 °C to 30 °C. However, in both clones assimilate allocation to the roots was strongly depressed. In the heat sensitive clone LT‐1 exposed to 30 °C root‐zone temperature, concentrations of soluble sugars in the apical root zone (0–10 mm) increased with time, presumably as a result of the cessation of root growth. The rate of nitrate absorption was not significantly affected by root‐zone temperature. However, the export of nitrogen (xylem exudate) was depressed in the heat tolerant clone whereas in the heat sensitive clone the export of total nitrogen and the proportion of nitrate increased. No effect of root‐zone temperature on ethylene release was observed in our experiments.
Correlation and Path Coefficient Analysis for Some New Released (00) Spring Rapeseed Cultivars Grown under Different Competitive Systems
Authors: Shabana R. , Shrief S. A. , Ibrahim A. F. , Geisler G. 
Published: April 2008

AbstractThe inter‐relationships between fifteen quantitative characters of spring oilseed rape were computed using four “free erucic acid” cultivars viz. Callypso, Semit 2080, Semu DNK 203/84 and Semu 304, grown under two different distances between drill rows (16 and 32 cm) and three population densities (30, 60 and 90 plants/m2). The experiments were carried out in Kiel, West Germany, in 1986 and 1987 seasons.Positive and highly significant values were obtained in the two seasons between seed yield per plant and the characters: dry matter (DM) per plant, per main stem and per branches, number of branches, siliqua per plant or per branches and yield per branches. All the characters that showed strong association with yield/plant behaved in a similar way and similar magnitudes with yield/branches. By contrast, yield/main stem showed different magnitudes in the two years with the previous characters and the association was weak or absent in most cases.Seed index and the quality traits (oil and protein %) did not correlate significantly with the majority of the characters studied. Only the association between DM/main stem and protein content showed highly significant negative values in both seasons.Path coefficient analysis revealed that number of siliqua per plant had the highest direct effect on seed yield/plant in both years. The source character (DM) affected yield/plant indirectly through number of siliqua per plant and the indirect contribution was high m both years.
Die Wirksamkeit von Fungiziden auf Qualität und Ertrag der Sommergerste (Hordeum vulgare L.) im Voralpengebiet Sloweniens
Authors: Tajnšek T. 
Published: April 2008

Abstract Effect of fungicides on fungus diseases and on the quality of the spring barley (Hordeum vulgare L.) in the subalpine area of Slovenia The 1000 kernel weight of brewer's spring barley can be enlarged by using fungicides triadimephone or propiconazole. Propiconazole has better effects on the net blotch. The both fungicides reduce protein contents, however, these alterations hasn't great practical value. By using the above mentioned fungicides, the yield of spring barley was statistically remarkably higher that that of unsprayed control. The 3 years average yield of cv. Kraguj sprayed with propiconazole was statistically remarkable higher than any other cultivar in any other experimented variant.
Yield Reaction of Winter Wheat in Monoculture in Dependence upon Weather and Soil
Authors: Sieling K. , Hanus H. 
Published: April 2008

AbstractOn the basis of a long‐term field experiment with a progessive monoculture of wheat carried out on the research station Hohenschulen (University of Kiel), the yield reaction of wheat in monoculture was analysed with help of a multiple regression approach.The mean yield of several years declines till the third resp. fourth crop, it increases later (‘decline‐effect’ in the larger sense) without reaching the initial level however.The weather considerably influence the absolute yield level as well as the yield trend in dependence upon the number of successive wheat crops. Interactions between yield and soil conditions are only slightly marked if the absolute yield is considered. The yield components, however, react differently according to the soil conditions.Crop management measures such as the choice of varieties and the application of BCM‐fungicides or N‐fertilization were only able to reduce yield losses, but not to prevent them.
Growth Characteristics of Contrasting Varieties of Perennial Ryegrass (Lolium perenne L.)
Authors: Taube F. 
Published: April 2008

AbstractA field experiment was conducted to study growth characteristics of contrasting varieties of Lolium perenne (early heading: Gremie; late heading Vigor) in different growth/regrowth periods during 1984 and 1985. A growth function was fitted to data of weekly measurements of dry matter production (DM) and leaf area index (L) to derive the following parameters according to quantitative analysis of plant growth: crop growth rate (C), relative growth rate (R), leaf area ratio (LAR) and leaf weight ratio (LWR). Furthermore phenological development of the swards was recorded.The chief differences in the growth potential of the varieties were found in primary growth on the one hand and in both investigated first regrowth periods on the other hand. In second and third regrowth periods no distinct differences were found either in DM nor in L regarding variety effects. In primary growth the early heading variety gained an advantage in DM, which was enhanced with prolonging growth period until the middle of June combined with a rapid reproductive development of the sward. Growth potential in the first regrowth period was determinated by the time of cutting in primary growth according to the development stage of the swards at cutting time. It was evident that highest values of DM and C were corresponding with a high amount of undamaged reproductive tillers in the sward. DM of vegetative summer regrowths were comparable, while in late summer/autumn under worsening environmental conditions a reduction in DM was observed. In opposite to that L developed rather similar in the investigated regrowth periods. According to this force of expression of L is discussed in relation to DM and phenological development of the swards.
Operational Research in the Ley‐Ruminant System
Authors: Torssell B. W. R. , Fagerberg B. 
Published: April 2008

AbstractThe concept of operational research in practical agriculture is introduced. Three aims of this approach are discussed and illustrated with actual examples in ley‐dairy farming‐to help understand and manage dynamic systems, such as growth‐to explain interactions and make predictions for current management measures, such as harvest time.‐to find alternative input combinations by sensitivity analyses.Prediction of ley growth and change in nutritional value illustrates the first point. It is shown that prediction of growth requires real time weather data but not necessarily weather forecasts. Alternatively, these can be substituted for data on normal weather conditions and some more extrem conditions of known probability.The second point is illustrated by analysing the main interactions that result in the margin above feed costs in the ley‐ruminant system. It is claimed that if the model satisfies an observed farm situation, as in this case, the explanation of the interactions is valid.The third point ‐ sensitivity analyses ‐ is illustrated by the higher margin over feed costs that is predicted in forage‐based feeding plans with 12‐15 kg DM forage, as compared to conventional feeding plans with 8 kg DM forage.The Discussion centres on (1) deterministic and stochastic models, (2) scale and experimental replication, and (3) statistical problems in parameter estimates and model validation:(1) When very dynamic systems are encountered, deterministic models may be difficult to validate. It is then far better to develop less precise stochastic models than to abolish the idea of model development. Such models would still predict risks and uncertainties.(2) With large systems such as production chains, experimental replicates often become too costly. A validated systems model then provides the possibility to explain unreplicated observations and state their generality.(3) Parameter estimates in mechanistic models require in many cases statistical developments because of problems encountered with non‐linear models where parameters may not be normally distributed.Requirements on model validation may differ when the models are used for long‐term or short‐term planning. In the second case, the model may be repeatedly calibrated to a current situation, and validation then includes the entire calibration procedure.
Ratoon Growth and Development in Rice (Oryza sativa L.) Under Various Temperature Regimes
Authors: Chauhan J. S. , Lopez F. S. S. , Vergara B. S. 
Published: April 2008

AbstractPlants exhibited differential response for ratoon growth and development under different temperature regimes before and after main crop harvest. Low temperature (23°/20 °C) before cutting induced ratooning whereas similar temperature after cutting delayed and reduced ratoon tillering. Ratoon grain yield and its attributes were significantly affected under various temperature regimes. Ratoon grain yield under low temperature regime before cutting did not differ from that of the control. Ratoon growth duration was maximum under low temperature regime after cutting. High temperature (37°/27 °C) after main crop cutting resulted in high spikelet sterility in the ratoon crop.
Effect of Water Status on Leaf Angle and Leaf Movement in Wheat
Authors: Peinetti R. , Ledent J. F. 
Published: April 2008

AbstractWater stress was imposed by watering withholding or application of PEG during the period following ligule emergence of Hag leaves or fifth leaves. Treatment reduced markedly the downward rotation of these youngest fully expanded leaves, and the angle finally reached. Leaf angle changes appear to be sensitive indicators of water shortage in wheat.