bluuebunny/crossref_metadata_2025 huggingface dataset:
Some investigations on Cox's disease in Cox's Orange Pippin apple trees, grafted on dwarfing rootstock M IX.
Authors: Veen B.W. , Locher J.T.
Published: June 2020

In 2-year sand and water studies with young Cox trees on M.9 and M.2 the effects were assessed of N deficiency, shading, impaired aeration of the growing medium and partial ringing. With trees grown in sand culture Cox disease occurred in the first year only, in the untreated control trees and in those grown under shade. With trees grown in water culture some roots suddenly stopped growing in July and the root tips died; by that time shoot growth had almost stopped and the shoots did not show any symptoms of the disease. Root die-back followed a period of good root growth, the no-N trees being the worst affected; however, some regrowth occurred, and by October recovery was best in the no-N trees. Studies with sand- and water-cultured trees of the distribution of 14C-labelled carbohydrates photosynthesized in the leaves showed that there was no accumulation of carbohydrates at the graft union and that carbohydrates were present in the root tips. Roots of the trees in water culture were longer and less branched than those in sand culture, suggesting a lower auxin content. Greater root length was associated with greater susceptibility to root mortality, indicating that Cox disease is associated with a low auxin level in the root system. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Theory of chromatography and its application to cation exchange in soils.
Authors: Reiniger P. , Bolt G.H.
Published: June 2020

Different types of solutions of the differential equation describing the process of cation exchange chromatography are compared and evaluated for their applicability to soil conditions. In cases where divalent cations replace monovalent ions, the exchange front assumes a stationary profile at an early stage which then yields an analytical solution provided a fairly simple exchange equation like that of Gapon or Vanselow is applicable. Where monovalent ions replace divalent ions, a non-stationary front arises, which is strongly dominated by the exchange equation. A good approximation of the front can be obtained by an analytical solution taking no account of diffusion or dispersion. Knowledge of the total electrolyte in the soil column is often the limiting factor in predicting the location and shape of the exchange front.[112.23.07]. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Studies on the amount and composition of digesta flowing through the duodenum of dairy cows. 1. Rate of flow of digesta measured direct and estimated indirect by the indicator dilution technique.
Authors: Klooster A.T. van 't , Kemp A. , Geurink J.H. , Rogers P.A.M.
Published: June 2020

1. Feed intake and the output of faeces, urine and milk were recorded for 8 to 10 days on 2 Friesian cows, with duodenal re-entrant cannulae, receiving hay and concentrates or fresh-mown herbage at the early or mature growth stage. One cow was also given 50 g calcined magnesite daily. During and in the 5 days preceding the collection periods 100 g polyethylene glycol (PEG) and 5.25 g Cr2O3 were given twice daily into the rumen. The digesta were measured and sampled from the re-entrant cannulae for 120 h in the middle of each balance period. All of the administered PEG and Cr2O3 were recovered from the duodenal digesta and faeces. The PEG content of duodenal digesta reached a peak 3 to 4 h after administration, but no diurnal pattern was observed for Cr2O3. The contents of PEG, Cr2O3, DM, Ca and Mg in spot samples of duodenal digesta taken at 2-h intervals agreed well with proportional samples collected during the same hours. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A non-specific mutagenic gene in cyclamen.
Authors: Wellensiek S.J. , Brenk G. van
Published: June 2020

A vegetative mutation from light pink to scarlet flower colour appeared to be determined by the same gene as the more commonly observed mutation from white to violet. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Rates of photosynthesis in leaves of wheat and barley varieties.
Authors: Dantuma G.
Published: June 2020

In 18 cultivars of spring wheat the range of difference in rate of photosynthesis of leaves was 22% (range 325-414 mg co2/cm2h), and in 12 cultivars of spring barley the difference range was 20% (range 284-366 mg CO2/cm2h). Measurement difficulties were initially found because of a high degree of variability within cultivars, but these were partly resolved by improving the conditions under which the plants were grown. Rates of photosynthesis reached a maximum in leaves that had attained their ultimate area, and then decreased gradually with ageing of the leaves. No evidence was found for regulation of photosynthesis by the demand for assimilates; photosynthetic capacity was determined mainly by leaf age. Low N supply and the resulting low protein content of leaves reduced the rate of photosynthesis. In leaves of a given age, but not in leaves of different ages, rate of photosynthesis was correlated with leaf protein content. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A comparison of some laboratory techniques for the estimation of the digestibility of the organic matter in forage samples.
Authors: Koelen C.J. van der , Es A.J.H. van
Published: June 2020

The 194 samples of forage were of 6 groups; grass or other forage dried, fresh or ensiled. Workers from 5 institutes analysed some of the samples by their usual methods, 10 methods altogether. Digestibility estimated with sheep was regressed on the other results and correlation coefficients and residual standard deviations were calculated; those were closer for groups of forages than for all forages together. The least accurate predictor of digestibility in vivo was crude fibre content, which is much used in the Netherlands. The best method for each fodder group was the method of Tilley and Terry (NAR 34, 156) as modified by Koelen, Kemmink and Dijkstra (De bepaling van de voederwaarde van ruwvoeders met behulp van de in vitroverteerbaarheid. Internal Report, Institute for Animal Feeding and Nutrition Research 'Hoorn' (1969), No. 27, available in English). It took least work but required sheep rumen fluid. For all groups together, the cell-wall constituents method of Gaillard and Nijkamp (NAR 38, 8034) was better for 54 samples but the residual standard deviation was higher than within groups; it required more labour, but not rumen fluid. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Observations on the fermentation of carbohydrates along the gastro-intestinal tract of a fistulated cow.
Authors: Gaillard B.D.E. , Klooster A.T. van 't
Published: June 2020

One cow was provided with cannulae in the proximal duodenum and terminal ileum. Three experimental rations were offered: 1, hay 7 kg/day and concentrate 6; 2, hay 3 kg/day, paper pulp 3 and concentrate 3.7; 3, fresh grass 11 kg DM/day. Rations 2 and 2 were given twice daily and 3 was offered more frequently. Experimental periods were 5 days in experiment 1 and 7 days in 2 and 3. Samples were taken from each cannula every 2 h for 5 days. Faeces were collected in each period. Flow rate of the intestinal contents was measured with polyethylene glycol and chromium sesquioxide as markers. Carbohydrates in the feed, digesta and faeces were fractionated according to solubility into ethanol-soluble sugars, alpha -glucose polymers, fructosan, water-soluble polysaccharides other than alpha -glucose polymers and fructosan, neutral-detergent-soluble polysaccharides and neutral-detergent residue. Sugars, sialic and uronic acids were measured in the hydrolysates and the sugars were separated chromatographically.Most of the ethanol-soluble sugars and all the fructosan was digested in the rumen, reticulum, omasum and abomasum, considered collectively as the stomach. Digestion of alpha -glucose polymer occurred mainly in the stomach and only 5 to 10% was digested in the small intestine and caecum with colon. The hay and concentrate ration contained more starch than the others and a higher proportion of this was digested in the small intestine and caecum with colon (20.3 and 6.8% of the digestible starch). The water-soluble fraction was digested mostly in the stomach; on rations 1 and 3 more component carbohydrates disappeared from the small intestine than the caecum with colon. Bacterial polysaccharides were thought to be digested in the small intestine and some bacterial growth was indicated, particularly on ration 2 which contained large amounts of cellulose. Fermentation and addition of bacterial polysaccharides and mucus confused the picture of digestion of the neutral-detergent-soluble fraction, but on all 3 rations it was higher in the small intestine than in the caecum with colon. The neutral-detergent residue was mainly fermented in the stomach and the caecum with colon. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Some effects of vernalization on the reproductive capacity of Lolium perenne L.
Authors: Kleinendorst A.
Published: June 2020

Vernalization requirements of grasses are reviewed, and data are given on experiments with perennial ryegrass showing considerable differences in vernalization behaviour between clones. Incomplete vernalization often increased the number of spikelets/inflorescence. Effects of soluble carbohydrate level are discussed. Experiments in which plants of perennial ryegrass were transferred into and out of a glasshouse during Jan.-Mar. indicated that the vernalization stimulus was not translocated between tillers. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The application of circular polarized light in soil micromorphology.
Authors: Pape T.
Published: June 2020

[120.031]Most polarization microscopes can be adapted to circular polarization without the need for expensive accessories. In soil micromorphological studies it eliminates the extinction phenomena caused by anusotropic compounds in thin sections, which is advantageous for direct observations, quantitative analyses and for microphotographical purposes. The method is especially valuable when a large microscope stage is used, which prevents turning of the table or the crossed polarizers. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A method to impregnate wet soil samples, producing high-quality thin sections.
Authors: Miedema R. , Pape T. , Waal G.J. Van de
Published: June 2020

[120.031]Mineral soils with different moisture content and texture were impregnated successfully by the method described. The water present in the soil sample is replaced by acetone and the acetone-saturated sample is impregnated by FitzPatrick's method (1970) (using acetone as thinner of the polyester resin Synolith 544). Shrinkage is minimal and the thin sections are of high quality. It should be possible to correlate thin section data obtained by this method with physical data obtained from undisturbed material. Micromorphologically, a better understanding of the plasmic fabrics should be possible. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Substrate utilization and respiration in relation to growth and maintenance in higher plants.
Authors: Vries F.W.T. Penning de
Published: June 2020

The significance and regulation of respiration in plants was investigated to determine how much C fixed by photosynthesis was lost during respiration. Relationships between growth, substrate utilization and maintenance were accurately calculated on theoretical grounds; results were in close accordance with experimental results for dark-grown maize embryos. Energy absorption by leaves was often 10-15% higher than expected mainly because at light saturation, surplus energy could be used for nitrate reduction. Comparisons of measured and calculated assimilation:dissimilation ratios in young plants indicated that substrates were used at their biochemically maximum efficiency. Maintenance processes required relatively low amounts of energy in rapidly growing tissues (>0.3 g/g day) but considerable proportions in other tissues, and were difficult to measure. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Aggregate stability of some alluvial soils from Egypt.
Authors: Kijne J.W. , Bishay B.G.
Published: June 2020

[134:116.46:141.621]The hypothesis that the Ca-Mg balance is the factor determining the structural stability of these soils was supported in the case of silty clay samples, where a positive correlation was found between the aggregate index and the Ca contents and Ca/Mg ratio, and a negative correlation with the Mg and Na percentage. With silty clay loam samples however a significant negative correlation was found between aggregate index and the Na content and percentage of 0.05-0.10 mm particles, and a positive correlation with the percentage of clay particles. In this case there was evidence that the presence of exchangeable Na aggravated the effect of Mg on aggregate stability. In both groups of samples the percentage of Na was correlated at P
Rhythmic growth phenomena in brussels sprout plants.
Authors: Kronenberg H.G.
Published: June 2020

Bud cuttings taken at regular intervals from brussels sprouts plants grown under different environmental conditions were rooted in peat moss, transplanted and grown under controlled conditions. Twelve weeks after striking plant heights of each series were measured. A marked periodicity in growth was observed, wih maxima (normal growth) and minima (retarded growth) 8-16 weeks apart. Differences in plant heights varied between 1 and 9 cm. The cause of these phenomena was considered to be endogenous. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Vegetative propagation of freesia through callus cultures.
Authors: Bajaj Y.P.S. , Pierik R.L.M.
Published: June 2020

Isolated segments of corm, stem, leaf, flower bud and anther from flowering freesia plants, cv. Ballerina, were induced to form callus on a modified Murashige and Skoog medium supplemented with NAA and 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA). Callus induction was best with young flower buds kept at 25 deg C in darkness. Callus could be sub-cultured in darkness on a medium containing auxin and cytokinin. Complete plantlets were obtained either by transferring the callus to light on an auxin-free medium containing kinetin or PBA, or from young anthers. Adventitious organ formation in explants and callus was closely related to the auxin/cytokinin ratio in the medium, rooting being promoted by auxins and bud formation by cytokinins. Root and bud formation were greater in light than in darkness. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Development of a synthetic compost for mushroom growing based on wheat straw and chicken manure.
Authors: Gerrits J.P.G.
Published: June 2020

A simple formula for the preparation of synthetic compost to complement existing formulae for the preparation of compost based on horse manure of pig manure is presented, and most of the important factors involved in the preparation are discussed. A synthetic compost with 1000 kg of chopped wheat straw, 1000 kg chicken manure, 60 kg gypsum and over 5000 l water was prepared. The mixture produced 3300 kg of compost. At filling, this compost had a C/N ratio of 18 a pH of 8.6, and contained 2% N and 0.4% NH4. Instead of chicken manure other N-rich organic materials can be used. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Quantitative measurement of fertilizer uptake by crops.
Authors: Broeshart H.
Published: June 2020

Little justification exists for using crop yield as an indirect measure of fertilizer uptake. Most commonly, fertilizer uptake is measured by the difference in nutrient yield of a crop growing in the presence or absence of fertilizer. The method recommended, (using isotopically labelled fertilizer) dispenses with the need for control plots. Application of the isotopic method to comparative studies on the placement, timing and nature of the fertilizer, to the measurement of fertilizer uptakes in the presence or absence of plant-fertilizer interactions, to the measurement of symbiotic N fixation by legume crops and to the fertilizer uptake by tree crops is discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Technology favourable to the environment by utilizing sulphite waste liquors from the pulp industry as organic nitrogen fertilizers. [German]
Authors: Flaig W. , Sochtig H.
Published: June 2020

Reviews a process developed at the Institute fur Biochemie des Bodens, Braunschweig-Volkenrode, W. Germany, for converting calcium-sulphite waste liquor, typically from pulping Picea abies, into a granular fertilizer after oxidative ammoniation. The product, known as N-Lignin, has given good responses in grain yield in container trials with summer rye and has at the same time diminished N losses by leaching, presumably as a result of an inhibition of nitrification. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of soil structure on phosphate nutrition of crop plants.
Authors: Prummel J.
Published: June 2020

On heavy, acid fluvial basin clay soil in small concrete-enclosed plots, growth of spring barley, sugar beet and flax was impaired by soil compaction treatment and by low P content of the soil. An interaction existed between these factors. To give a comparable P response higher P availability was necessary in soil of poor structure. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The influence of the method of preservation of forages on the digestion in dairy cows. 2. Digestion of organic matter, energy and amino acids in forestomachs and intestines.
Authors: Tamminga S.
Published: June 2020

2. Two dairy cows with duodenal reentrant and rumen cannulae were given diets containing artificially dried and pelleted grass (GP), grass silage treated with formic acid (GSF), grass silage treated with a mixture of formic acid and formaldehyde (GSFF) or grass silage without additive (GS). DM intake was 14.8 to 16.0 kg/day and about 30% of the N in the diets was from grass pellets or silages. Between 45 and 57% of the apparently digested organic matter and between 26 and 41% of the apparently digested energy disappeared before the intestines. The higher values were found with GSF and GS.Total amino acid N reaching the duodenum was between 104 and 134% of intake, highest with GP and GSFF. The amounts of individual amino acids reaching the small intestine were from 75 to 270% of the amounts ingested. High values (>150%) were found for glycine, lysine, methionine and tyrosine; low values (
Comparative response to nitrogen deficiency of a tropical and temperate grass in the interrelation between photosynthesis, growth, and the accumulation of non-structural carbohydrate.
Authors: Wilson J.R.
Published: June 2020

A tropical grass, Panicum maximum var. trichoglume and a temperate grass, Lolium perenne, were grown in controlled environment rooms at near optimum temperatures of 25 and 18 deg C, respectively. After an initial period of growth on full nitrogen nutrient solution, a proportion of the plants of both species were transferred to 'nil' N nutrient solution. A sequence of destructive harvests was taken as the plants became increasingly N deficient, and calculations were made of relative growth rate (RW), relative leaf area growth rate (RA) and net assimilation rate per unit leaf area (EA). On a similarly treated group of plants, net photosynthetic rate (PN) and dark respiration rate of attached leaves were measured.Organic and nitrate N were estimated on the photosynthesis-tested leaves, and on comparable leaves from the growth analysis plants at each harvest. Percentage total non-structural carbohydrate (%TNC) was estimated for P. maximum only.P. maximum maintained a higher RW and PN than L. perenne at comparable percent leaf N. With increasing N stress, EA of both species declined to a similar relative extent, but RA of P. maximum decreased much less than that of L. perenne. This difference in response to N between the species in the balance of assimilate input and consumption in new growth may in part explain why, under N deficiency, published studies indicate that % TNC reach higher levels in L. perenne and other temperate grasses than in tropical grasses such as P. maximum. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Energy-dispersive X-ray analysis on thin sections and unimpregnated soil material.
Authors: Bisdom E.B.A. , Henstra S. , Jongerius A. , Thiel F.
Published: June 2020

A combination of scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXRA) was used in the study of soil materials. The investigation in situ of components in thin sections was used to estimate chemical elements with atomic numbers 11 upwards, from sodium on. EDXRA could detect chemical elements up to magnifications of X 10 000. The composition of amorphous and micro-crystalline materials cannot be estimated in thin sections by light microscopy but by this technique was clearly displayed. Composition of loose soil material can also be investigated. The material that could be studied by SEM-EDXRA did not need high polishing of the thin section, and the plastic used for impregnation of the soil material was not affected by the investigation.Identification of chemical elements in situ, high resolution of the topographic image and relatively short testing times for the elements make this combination of techniques useful for soil research. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Gibberellin promotion of physiological leaf spot in detached 'Golden Delicious' apple leaves.
Authors: Kender W.J. , Jonkers H.
Published: June 2020

The development of leaf spot, a non-pathogenic disorder specific to the cv. Golden Delicious, was accelerated in detached leaves (whether previously unmarked or showing leaf spot) when these were cultured in solutions of GA3 or GA4+7 at 10, 50 or 100 mg/l for 72 h. About 15% of the foliage on the trees exhibited leaf spot at the time selected leaves were detached for culture. In a second experiment with cultured leaves the interaction of PBA and GA4+7 applied simultaneously was highly synergistic in increasing the severity of the disorder when compared with the effect of either growth substance alone. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Substitution of labour and energy in agriculture and options for growth.
Authors: Wit C.T. de
Published: June 2020

The opportunities for human labour and energy substitution in agricultural growth are investigated, with special attention to the Netherlands. From the technical aspect labour and energy can be viewed as the two basic production factors of agriculture. Methods of calculating labour and energy requirements are first discussed, beginning with the production means employed up to the final product of agriculture. Limited quantities of additional labour and/or energy are required in order to achieve the maximal quantity of production per ha. agricultural land. The function which brings the demand for both these resources into relation at the production level, is presented under two limiting situations: (1) the minimal additional amount of labour required with unlimited energy available, and (2) the minimal amount of energy with unlimited labour available (the typical situation in most developing countries). With the help of these functions, functions of the same yield level are constructed for the variable input of the two factors; these factors show the opportunities for a substitution of labour and energy in the agricultural production process at different yield levels. The form of this "growth path" shows that there exists a majority of production situations in which the yield per unit of additional energy, the yield per unit of additional labour input and the yield per area unit with increasing input of labour and energy per ha. increases, while at the same time the additional energy input per unit of additional labour input decreases. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Carbonate in soil: a theoretical consideration on, and proposal for its fabric analysis. 2. Crystal tubes, intercalary crystals, K fabric.
Authors: Bal L.
Published: June 2020

The spatial arrangement (fabric) of carbonate in 7 different soils was studied to make a proposal for its fabric analysis. These soils, which have been developed in calcareous loess and marine deposits, are located in Afghanistan, the USSR, Germany and the Netherlands.In the first part of this study (Bal, 1975) the simple plasmic fabrics crystic, calcic and fibrous have been defined. Their distinction is primarly based on theoretical considerations of Brewer's concepts (Brewer, 1964).In this second part the morphology and genesis of carbonate crystal tubes and intercalary carbonate crystals is dealt with.Also K-fabric, the carbonate fabric introduced by Gile et al. (1965) is discussed and redefined. The fabrics crystic, calcic and fibrous are simple fabrics; the K-fabric, on the contrary, is principally a compound fabric. This means that K fabric is composed of one or more of these simple fabrics. (Abstract retrieved from CAB Abstracts by CABI’s permission)
CO2 from gas-fired heating boilers - its distribution and exchange rate.
Authors: Berkel N. van
Published: June 2020

Glasshouse levels of CO2 were recorded on 2 tomato and 2 chrysanthemum holdings in which CO2 enrichment was provided via gas-fired heating boilers. The daily levels could range widely, from 300 to 6000 p.p.m. More consistent levels of distribution were provided by using a main duct with lay-flat perforated plastic tubing than by using a main duct with holes through which the CO2 was fed directly into the greenhouse. The latter system produced a more pronounced CO2 gradient with tomatoes than with chrysanthemums. Levels within and outside the beds did not differ except in the case of chrysanthemums supplied with CO2 from a main duct with lay-flat tubing, where levels at a height of 10 cm were markedly greater than elsewhere. A close relationship was found between the internal air exchange rates (with the ventilators closed) and the wind speed. The exchange rates varied from 0.2 to 1.4 times/h. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Self-stopping tomatoes - cultural and economic aspects.
Authors: Visser A.J. de , Buitelaar K.
Published: June 2020

The labour requirements and costs for growing 2 crops of traditionally trained tomatoes per year are contrasted with those estimated for an experimental sequence of 4 self-stopping crops in which specially bred plants are grown at a high density, with little or no lateral growth and once-over harvesting. In preliminary trials with prototype plants, it was necessary to provide support and to remove side-shoots at least twice, and fruit set was enhanced by using a high-pressure sprayer. The need for further developments in cultural techniques and breeding programmes for self-stopping crops is discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Thiram residues on glasshouse lettuce.
Authors: Theune D. , Bravenboer L.
Published: June 2020

Thiram dust was applied at different concentrations and dates to lettuce crops and residue levels were analysed at harvest or at weekly intervals. The growth of the plant was the major factor influencing residue levels. The later the application the greater was the residue. The use of irrigation, either by spray lines or trickle equipment, appeared to have only a small effect on residue levels. Some of the fungicide could be washed off, but only if irrigation was applied in the early stages of crop development. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Uptake of cadmium and zinc by ryegrass at high solution culture levels.
Authors: Dijkshoorn W. , Lampe J.E.M. , Kowsoleea A.R.
Published: June 2020

New top growth of ryegrass exposed to various solution culture levels of cadmium and zinc absorbed the elements without detectable interaction between the two. When after repeated clippings the contents had risen to 100 mg cadmium/kg DM or 700-1000 mg zinc/kg DM the new growth was injured. Interaction of zinc in cadmium toleration was suggested by the growth response but could not be established with certainty. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Callus multiplication of Anthurium andraeanum Lind. in liquid media.
Authors: Pierik R.L.M.
Published: June 2020

The growth of callus tissue from adult A. andraeanum plants was best in a modification of Murashige and Skoog's medium. On this medium genotype A 42-3 reached a fresh weight multiplication rate of 30.7 when grown for 5 weeks at a rotation speed of 120 rev/min, at 25 deg C and in continuous darkness. The fresh weight multiplication rate of 6 other genotypes of the same species varied considerably when grown on the best medium for A 42-3. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Reflection of radar waves by soils, crops and forest: a review of some recent Dutch work.
Authors: Janse A.R.P.
Published: June 2020

Reviews the principles of measurement of radar reflection and some studies on three landscape types in the Netherlands. Measurements on forest (several stand types) were made from a television tower near Eindhoven in winter 1972/73 and compared with ground-survey data. Radar reflection increased gradually with increasing stem numbers/ha, being influenced largely by the canopy (owing to its high water content) and very little by tree height or stem diameter. At greater distances, the taller trees acted as a screen preventing further measurement. The technique is regarded as promising.
ADDITIONAL ABSTRACT: The use of radar reflection as a classifier for agricultural purposes is discussed and demonstrated. The results of some series of measurements being performed by a Dutch working group in collaboration with the Agricultural University is mentioned, together with the problems of data handling. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Freesia plantlets from flower-buds cultivated in vitro.
Authors: Pierik R.L.M. , Steegmans H.H.M.
Published: June 2020

Flower-buds of 10 freesia cvs were grown in vitro and were induced to regenerate adventitious buds on a modified Murashige and Skoog's medium containing PBA and IAA. The formation of adventitious buds was strongly enhanced by growing the explants first in darkness and subsequently in light. Subcultured shoots, grown on a medium with IAA, could be rooted easily and viable plants were obtained. (Abstract retrieved from CAB Abstracts by CABI’s permission)
An inceptisol formed in calcareous loess on the 'Dast-i-Esan Top' plain in North Afghanistan. Fabric, mineral and trace element analysis.
Authors: Bal L. , Buursink J.
Published: June 2020

The calcixerollic xerochrept described has a low bulk density (1.1 g/cm3) which is attributed to faunal activity. The average mineral composition was 25% quartz, 20% CaCO3, 15% feldspars, 15% micas, 15% chlorites, 2-3% other minerals and 10% amorphous material and there was a clear relationship between minerals and particle size fractions. Trace element contents were 0.6, 11.0, 23.2, 49.1; 19.4, 75.9, 18.7 and 525 mg/kg for V, Cr, Co, Ni, Cu, Zn, Sr and Ba, respectively. Sr and Ba contents were related to carbonate redistribution. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Flower induction in perpetual kale (Brassica oleracea var. ramosa DC).
Authors: Kronenberg H.G.
Published: June 2020

Complete (100%) floral induction could be induced in 14-week old plants by ten weeks' treatment at 2 deg or 6 deg C or by eight weeks' treatment at 4 deg C. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Climate, nitrogen and grass. 7. Comparison of production and chemical composition of Brachiaria ruziziensis and Setaria sphacelata grown at different temperatures.
Authors: Deinum B. , Dirven J.G.P.
Published: June 2020

7. In order to test the validity of previous results, a trial was performed in greenhouses on the effect of temperature, age and N level on production, morphological and chemical composition of Brachiaria ruziziensis Germain & Evrard and Setaria sphacelata (Schum) Stapf & Hubbard. The 2 grasses were equally productive, but Setaria had a lower optimum temperature. Brachiaria was leafier than Setaria and had higher contents of nitrate and protein; it was also more digestible. It had higher contents of cations, inorganic anions and organic acids, but its oxalate content was lower both in leaves and in stems. Leaves of Brachiaria were much richer in nitrate than those of Setaria at the same protein content. At a greater age, both grasses had higher yields that originated from a greater number of heavier tillers. Plants were less leafy; nitrate and protein contents, and digestibility of organic matter were lower, but percentage of cell-wall constituents was higher. Increase of temperature stimulated plant development in both grasses, causing lower protein content and lower digestibility of organic matter in leaves and stems. Temperature also had a direct negative effect on stem digestibility apart from its effect on stem development. N application increased production, nitrate and protein content in both grasses, but had hardly any effect on plant development and digestibility. Consequently, Setaria reacted to environmental conditions like the other tropical grasses studied in this and previous trials, so confirming the conclusions. (Abstract retrieved from CAB Abstracts by CABI’s permission)
On the methylation of inorganic mercury and the decomposition of organo-mercury compounds - a review.
Authors: Lexmond T.M. , Haan F.A.M. de , Frissel M.J.
Published: June 2020

Mercury is subjected in nature to a number of turnover reactions. The conversion of inorganic to organic forms is governed by microbial methylation which may proceed at aerobic and anaerobic conditions. Decomposition of organic mercurials may follow a chemical or a microbial pathway. The reactions and mechanisms occurring in soils, water, sediments and laboratory cultures are described. 53 references. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Relative dormancy in excised vegetative buds of Rhododendron.
Authors: Pierik R.L.M.
Published: June 2020

Excised vegetative buds of Rhododendron cv. Pink Pearl, present in the axils of the bud scales, required light for sprouting, but no special daylength was necessary to break dormancy. Glucose greatly enhanced sprouting, but was not essential. Glucose could not replace light, but light could partly replace glucose for inciting sprouting. Only fully developed buds were capable of sprouting. Temperature played a decisive role, 21-25 deg C being the optimum range. Macroelements were not essential, but sprouting on a medium without macroelements was reduced. It was impossible to induce adventitious root formation on excised shoots grown on a medium containing IBA. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Herbage yield and quality relationships of three varieties of Setaria sphacelata (Schumach.) Stapf and Hubbard.
Authors: Wijk A.J.P. van
Published: June 2020

Primary growth of S. sphacelata cv. Nandi I, Nandi II and Nandi III was cut at 3-wk intervals during 1973 and 1974. Dm yield, percentage DOM, percentage CP in the DM and some morphological characters were determined at each cut. When compared at a given date, digestibility of the 3 cv. did not differ significantly, but at the same growth stage the early-heading cv. had a higher digestibility than later-heading cv. The early cv. had a significantly higher DM production than the late cv. when the 2 yr were combined. During early stages of growth, stem digestibility was higher than leaf digestibility. DM yield and quality could be improved without affecting seed production by increasing leaf percentage at mature stages together with selection of early-heading plants. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Wavelength and energy-dispersive X-ray microanalysis with EMA and SEM-EDXRA on thin sections of soils.
Authors: Bisdom E.B.A. , Henstra S. , Hornsveld E.M. , Jongerius A. , Letsch A.C.
Published: June 2020

Organic matter, minerals and iron-manganese nodules were studied in thin sections of soils with an electron microprobe analyzer (EMA) and a combination of a scanning electron microscope (SEM) and an energy-dispersive X-ray analyzer (EDXRA). Both instruments were used to estimate the presence and nature of chemical elements in two selected areas, one containing a combination of organic and mineral material and another inside an iron-manganese nodule. The detection of organic matter proved problematic. Of the light elements, N could not be detected with EMA and O was detected but was not specific to organic matter. EMA could not be used for C because of the C coating of the thin section. SEM-EDXRA only detected heavier elements. EMA produced somewhat better X-ray images of heavier elements, especially from an iron-manganese nodule. However, with organic material, SEM-EDXRA X-ray images were similar to or slightly better than EMA. An advantage of SEM-EDXRA over EMA is that the soil material can be analysed at various magnifications with a much higher limit, and point analysis can be made of loose material. For soil material, SEM-EDXRA was better as a routine instrument which solved most problems. EMA can be used as a complementary instrument. Other microanalytical techniques such as the ion microprobe mass analyzer (IMMA) were necessary to analyse light elements in organic material of soils. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Multi-point temperature measuring equipment for crop environment, with some results on horizontal homogeneity in a maize crop. 1. Field results.
Authors: Stigter C.J. , Birnie J. , Jansen P.
Published: June 2020

The use of temperature measurements above, below and within plant stands in physiological and ecological studies is briefly reviewed and the choice of sensor and protection from radiation effects in measuring temperatures within a maize crop are discussed. The horizontal homogeneity of temperature was investigated. Measurements in 1973 and 1974 showed the greatest horizontal temperature difference at 1.8 m above ground level due to an increase in leaf area density just above the height where the crop became closed and air flow was reduced; at lower levels temperature differences increased as turbulence was reduced, and differences in soil surface conditions influenced temperature measurement. The need for a large number of measuring points in the lower parts of the canopy is emphasized. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Southeast Asia - potential world food basket.
Authors: Liere W.J. van
Published: June 2020

It is suggested that southeast Asia has all the necessary prerequisite potentials in terms of land, water, year-round suitable climate and human resources to become a major world food basket. At the moment production is rather low, as is demonstrated for a number of crops by comparing average farm yields with yields obtained under controlled conditions of the experimental stations in the area. Mass application of modern technology, including water control and improvement of soil fertility, would be capable of closing the gap between present and potential production. The programme of agricultural planning and research sponsored by the Mekong Committee represents a major initial step in this direction, aiming to bring about changes from traditional agricultural practices to progressively greater use of modern technology, tailored to suit local conditions, in order to achieve higher sustained yields.
ADDITIONAL ABSTRACT: It is suggested that S.E. Asia has all the potential requirements of a major food producer in terms of land, water supply, climatic conditions and labour resources. The large difference between present and potential crop yields under experimental conditions could be reduced by improved agronomic techniques. Lack of water control is the major factor limiting rice production in the lowlands where paddy yields are generally 1-2 t/ha compared with an attainable yield of 6 t/ha. In upland areas, soil fertility is the most important factor limiting yields and the wider use of multi-cropping or inter-cropping could greatly increase production. The potential of water conservation schemes such as the Pa Mong Reservoir on the Mekong River between Thailand and Laos is considered. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Evaluation of phosphate in fertilizers by means of the alkaline ammonium citrate extraction according to Petermann.
Authors: Boxma R.
Published: June 2020

The phosphate extraction with alkaline ammonium citrate solution for the control of phosphate in fertilizers was subjected to a critical examination. The contribution of inferior phosphate forms such as tricalcium phosphates and apatites to the available P2O5 percentage can be excluded to a great extent by using a narrow sample solvent ratio. However, the dissolution rate of dicalcium phosphate in alkaline ammonium citrate solution limits the narrowing of the ratio. The dissolution rate of dicalcium phosphate can be increased, if instead of intermittent manual shaking, mechanical shaking is applied. Extraction of 1.0 g sample with 200 ml of alkaline ammonium citrate solution at 65 deg C under mechanical shaking for 1.5 hours is preferred to other methods for quality control of phosphate in fertilizers. The extraction method with neutral ammonium citrate solution is not reliable, because this method makes little or no distinction between high quality and low quality fertilizers. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Multiple cropping of maize and soya beans under a high level of crop management.
Authors: Beets W.C.
Published: June 2020

Intercropping maize with soyabeans in 6 different spatial arrangements reduced the grain/seed yields/unit area of both crops. Maize alone with optimal plant populations produced the maximum yield of grain and energy, whereas associations of maize and soyabeans produced maximum total fat, protein and methionine yields. Associations used the land more intensively and land equivalent ratios of all intercropping systems were higher than of monocultures of maize and soyabeans. Different ways of evaluating mixed cropping trials are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
An application of a multiple regression method in tropical grass breeding.
Authors: Wijk A.J.P. van
Published: June 2020

A computer programme is described for selecting a subset of independent variables for prediction of a dependent variable. The programme is illustrated by data taken over three years on tillering, date of head emergence, plant erectness, tiller dry weight, plant fresh weight and head number in Setaria sphacelata 'Nandi 1'. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Problem hydromorphic soils in north-east Thailand. 2. Physical and chemical aspects, mineralogy and genesis.
Authors: Brinkman R.
Published: June 2020

The Roi Et soil, which occurs on the extensive seasonally wet low terrace, is a silt loam with low clay contents in the surface horizon; the clay content increases with depth. The soil is seasonally water-saturated and seasonally dry, has considerable porosity, but has a dense ploughpan at a depth of about 0.2 m and a dense substratum below 1.4 m. The soil is strongly acid with a low base saturation and a very low cation exchange capacity. The silt and sand are 98% quartz. Disordered kaolinite is the main clay mineral. About a fifth of the clay fraction is soil chlorite - a strongly Al-interlayered vermiculite in the upper horizons but partially Al-interlayered in the substratum. The interlayers contain a small amount of ferrous iron. The quartz contents in the clay fractions range from one tenth in most of the profile to about three tenths in the surface horizon, with a corresponding decrease in kaolinite. The kaolinite in the upper horizons shows signs of dissolution. These data are in accordance with hypothetical clay eluviation-illuviation and long-continued Fe redistribution and ferrolysis, the ferrolysis involving clay alteration and dissolution under conditions of alternating reduction and oxidation of Fe. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The influence of temperature and light intensity on grain growth in relation to the carbohydrate and nitrogen economy of the wheat plant.
Authors: Spiertz J.H.J.
Published: June 2020

The response of wheat grain growth to temp. and light intensity was studied under controlled conditions within the ranges 10-25 deg C and 64-188 W/m2, resp. Warmth hastened plant senescence and enhanced the initial growth rate of the grains. Additional light promoted the rate of grain growth more at high than at low temp.; under the latter conditions there was a considerable accumulation of carbohydrates in the stem (up to 40%) from anthesis onwards. The rate of grain growth ranged from 0.70 to 1.64 mg/day grain. The duration of grain growth was prolonged by decrease from 25 to 10 deg ; the increase in growth duration from about 30 to 80 days corresponded with a relatively stable temp. sum. Temp. and light also affected the redistribution of assimilates and the chemical composition of the grain. The rate of protein synthesis was promoted more by warmth than the rate of starch synthesis. This resulted in an increased N content of the grain. The final content of total non-structural carbohydrates (starch and sugars) was slightly decreased by warmth. Additional light raised the carbohydrate content of all parts of the plant and so decreased the N content of these parts. However, light intensity had less effect on N distribution and yield than temp. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Maximization of arable crop yields in the Netherlands.
Authors: Sibma L.
Published: June 2020

The yields in kg/ha were calculated for potatoes, sugar beet and winter wheat for conditions under which water and mineral supply were not limiting growth rates. The date at which a closed crop canopy can be obtained in spring was an important criterion for the yield. Growth analyses of silage maize and sugar beet confirm that relatively high yields can be further improved by accelerating leaf development in spring. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Inheritance of temperature-dependent string formation in common bean (Phaseolus vulgaris L.).
Authors: Drijfhout E.
Published: June 2020

String formation was analysed in F1, F2 and F3 generations of crosses between cultivars without string, with incomplete string and with complete string, and in B1 and B2 generations of the hybrid between a stringless and a stringy cultivar back crossed to the stringless parent. F1 plants were maintained at constant temperatures of 17 and 23 deg C, and the remaining plants were maintained at 23 deg C, to promote string formation. Segregation ratios suggested that two genes were involved in string development, stringlessness and complete string formation being controlled by the dominant and recessive alleles respectively of St, and incomplete string development, at high temperature and in genotypes with the dominant St allele, being controlled by the dominant allele of the second gene (Ts). (Abstract retrieved from CAB Abstracts by CABI’s permission)
Improvement of flowering in Calceolaria by cold treatment and selection.
Authors: Kho Y.O. , Baer J.
Published: June 2020

Cold treatment for 4 weeks at 10 deg C resulted in shortening of the uneven flowering period as a consequence of a delay of the early-flowering and an advance of the late-flowering plants. For the selection material used, the effect was notably a delay of the early-flowering plants. The percentage of flowering plants was favourably influenced by cold treatment. The number of simultaneously flowering plants was also increased by selection, although to a lesser extent. (Abstract retrieved from CAB Abstracts by CABI’s permission)