bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of tree species on soil productivity.
Authors: Goor C.P. van
Published: June 2020

A general discussion with a bibliography of recent literature. A reappraisal of earlier studies in Europe suggests that the dieback of 2nd-rotation coniferous plantations on poor soils was due to intensive site preparation leading to losses of soil organic matter. Afforestation, which generally increases site fertility, can be preceded by complete soil cultivation without ill effect. A strategy is proposed for silvicultural management according to the stage of ecological development of forest ecosystems. A methodology is also proposed for determining the impact of individual species on soil productivity. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Growth and morphogenesis of shoot initials of Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, in vitro.
Authors: Evers P.W.
Published: June 2020

A method of micropropagation of Douglas fir is described. Differences in morphogenesis and photosynthesis were found in shoot initials that had been isolated from buds in 10 topophysical positions on 2-yr-old trees. These differences were influenced by medium composition and light intensity, and by forcing, topping or growth regulator treatment of the mother trees. Shoots originating from buds in less exposed parts of the tree generally had a higher relative growth rate, max. net photosynthesis and photochemical efficiency and a lower compensation irradiance. Seasonal changes were found in the optima for nitrate and sucrose concn. in the medium and for light intensity. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Relation of protein synthesis and amino acid oxidation: effects of protein deprivation.
Authors: Schreurs V.V.A.M. , Mensink G. , Boekholt H.A. , Koopmanschap R.E.
Published: June 2020

For up to 3 weeks 10 male rats weighing about 300 g were given diets which had 20% protein or were free from protein but supplied similar amounts of energy. The rats were killed at intervals; the last 2 were given L-[U-14C]tyrosine by infusion 4 h before they were killed. The deprived rats showed restricted amino acid oxidation and a decreased rate of protein synthesis. Amino acid oxidation continued by an uneven loss of proteins from the tissues. In muscle the composition and relative synthesis rate of the constituent proteins were not affected. Liver and kidney, compared with other tissues tended to maintain a relatively high rate of protein turnover. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Transfer of cadmium, lead, mercury and arsenic from feed into various organs and tissues of fattening lambs.
Authors: Veen N.G. van der , Vreman K.
Published: June 2020

Supplementary cadmium, lead, mercury and arsenic were given to 48 (32 housed, 16 grazed) fattening lambs 10 weeks old for 3 months. Elements were incorporated in concentrates as soluble compounds or as present in biological sludge. When diet was supplemented with soluble compounds content of Cd, Pb, Hg and As was 2, 10, 0.1 and 2 mg/kg DM, respectively. When biological sludge was added to the diet corresponding values were 1, 14, 0.3 and 2.5 mg/kg DM and 1, 18, 0.2 and 1 mg/kg DM. Only As increased in muscle tissue as a response to increased intake. Cd and Pb contents of liver and kidney increased with increased intake. For lambs given soluble compounds Pb and Cd in liver and kidney were similar at 0.3 and 1 mg/kg, respectively. In brain tissue only Pb was increased. Hg in kidney was about 10 times higher than in liver. When Hg was given as a soluble compound, concentration in kidneys of lambs kept on pasture was 0.4 mg/kg. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The effect of ambient temperature and activity on the daily variation in heat production of growing pigs kept in groups.
Authors: Hel W. van der , Duijghuisen R. , Verstegen M.W.A.
Published: June 2020

In two experiments, pigs with initial weights of 20 kg were kept in climate-controlled respiration chambers. After a 7-day adaptation period at 22-24 degrees C the temperature was reduced in 4 degrees C steps to 8 degrees C and then increased to 24 degrees C. Each temperature treatment lasted 3 days. Feed contained 12 kJ metabolizable energy per g and was given at 93 and 83 g/kg0.75 per day in experiments 1 and 2, respectively. Lower temperature increased 24 h heat production, but not 24 h activity. The mean activity periods moved from before and after feeding to after feeding, especially in the afternoon. During the afternoon, activity decreased at the lower ambient temperature, whereas metabolic rate remained constant. It is concluded that the effect of ambient temperature on metabolic rate depends on the time of day. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Adventitious plantlet regeneration from floral stem explants of Nerine bowdenii W. Watts.
Authors: Pierik R.L.M. , Steegmans H.H.M.
Published: June 2020

Explants (1.5 mm thick) from the floral stems of cv. Favoriet were cultured on a basal medium (containing Murashige and Skoog micro-elements, half-strength macro-elements and 4% sucrose) with 1 mg/litre BA and 0.5 mg/litre NAA, at 18 degrees C in continuous darkness. Bulblet regeneration was strongly influenced by the age (length) of the original floral stem, optimal regeneration occurring with immature stems 2.5 to 10 cm in length. To obtain plantlets the regenerated bulblets were subcultured on a cytokinin-free medium (with macroelements increased to full strength) at 25 degrees in continuous light. Plantlets were easily transplanted into soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Modelling food policies and food production.
Authors: Tims W. , Faber D.C.
Published: June 2020

The Centre for World Food Studies in Amsterdam is developing economic policy models focussing on food and agriculture, and incorporating detailed agronomic information. The structure of these national models is such that they can be linked in order to analyse international trade. The developing country models emphasize and analyse the problem of hunger and poverty through the role of agronomic and livestock constraints, the changes in the distribution of income between agriculture and non-agriculture as well as within agriculture. Model alternatives can be analysed through changes in various parameters, such as direct and indirect tax rates, tariffs, buffer stocks, import and export quotas. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The evolution of agricultural marketing theory: towards better coordination with general marketing theory.
Authors: Meulenberg M.T.G.
Published: June 2020

The thesis of this paper is that in agricultural marketing theory the basic approach to marketing problems should be the 'marketing management' approach. In order to substantiate this thesis, the developments in agricultural marketing and general marketing theory are concisely reviewed. The elaboration of marketing management in agricultural marketing is discussed in relation to the properties of the marketing environment and to the marketing capacities of an agricultural marketing system. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Remote sensing in the water management practice.
Authors: Menenti M. , Nieuwenhuis G.J.A.
Published: June 2020

In this examination of the use of remote sensing in water management 3 case studies are presented. The first concerned water management in the eastern Netherlands and remote sensing was used to provide evapotranspiration values. The description of the hydrological conditions was markedly improved by combining remote sensing and hydrological model calculations. A case study in Argentina using Greenness Vegetation Index showed how remote sensing can be used to give data on irrigated area and crop type. In the third case study, remote sensing was used to investigate groundwater losses in a desert area in Libya. The use of theoretical and experimental research in remote sensing, remote sensing applications in the Netherlands and remote sensing applications in developing countries are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Proton balance of plants: physiological, agronomical and ecological implications.
Authors: Findenegg G.R. , Beusichem M.L. van , Keltjens W.G.
Published: June 2020

Various aspects of proton balance in plants are reviewed including the balance in plants taking their nitrogen supply from various sources, recirculation of nutrients in plants, the H ion status of plants, lime-induced chlorosis and the effects of soil acidification and ammonia deposition. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Energy values of feeds for livestock and their prediction.
Authors: Es A.J.H. van
Published: June 2020

Several methods for predicting feed energy values for livestock are discussed. These include in vivo digestibility trials, which are being replaced by enzymatic and plant cell partitioning, and a new method using absorption and reflection of near-infra-red light. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Development of animal breeding research.
Authors: Politiek R.D.
Published: June 2020

This article outlines the scope of research on the genetic improvement of farm livestock in the Netherlands, and briefly describes the main current projects in the breeding of beef and dairy cattle. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Cadmium and lead in compounded feeds.
Authors: Vos G. , Teeuwen J.J.M.H. , Vreman K.
Published: June 2020

Cadmium and lead were estimated in 452 compounded feeds for dairy cattle, sows, piglets, growing pigs, layers and broiler chickens. The average Cd content was 0.126 to 0.174 mg/kg. In 88% of samples Cd content was 0.5 mg/kg. The average Pb content was 0.82 to 1.70 mg/kg. The maximum permissible concentration of 5.0 mg/kg was exceeded in only 2 samples. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Inorganic chemical analysis of plant tissue: possibilities and limitations.
Authors: Houba V.J.G. , Novozamsky I. , Lee J.J. van der
Published: June 2020

The variability of analytical results for determination of 23 inorganic components in different plant materials was evaluated, using data obtained over the last 5 years of an extensive (on the average 120 participants) bimonthly collaborative interlaboratory study. In particular, the relation between content level and coefficient of variation (CV) was examined. Usually, a constant CV value was found at high content levels, with a sharp increase in CV at low levels. The precision found for N, P, K, Ca, Cl, Mg, Zn and nitrate was high enough (CV < 20%) to yield reasonably comparable content values. Comparison of analytical results for B, Cu, Fe, Cd, Mn and Na, may be difficult, since about 20% CV was already reached at the levels usually present in plant material. The analytical results for Al, Co, Cr, Mo, Ni, Pb, S, Se and sulphate varied considerably, irrespective of the content level, which means that comparable results are very hard to produce with these components. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Heterogeneity and electrolyte adsorption: intrinsic and electrostatic effects.
Authors: Riemsdijk W.H. van , Koopal L.K. , Wit J.C.M. de
Published: June 2020

Adsorption of electrolytes in natural systems is an important phenomenon. Natural systems contain sorbents with a predominantly constant surface charge, such as clay minerals, as well as a complex mixture of mainly variable charge sorbents like organic matter, both in the dissolved and in the soil solid phase, and metal oxides. The effect of a combination of an intrinsic-affinity distribution (both discrete and continuous) and a variable surface potential on adsorption behaviour of protons is discussed both for random and patchwise heterogeneity. It is shown that the variable charge (potential) or intrinsically homogeneous metal oxides and organic model colloids leads to an apparent heterogeneity of binding sites. This effect is quantified with simulated data and condensation approximation. For heterogeneous charged sorbents, where the apparent affinity represents both chemical heterogeneity and electrostatic interactions, very wide apparent-affinity distributions will be found. The apparent-affinity distribution is in general only a poor representation of the intrinsic-affinity distribution. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The role of soil chemistry and soil physics in protecting soil quality: variability of sorption and transport of cadmium as an example.
Authors: Haan F.A.M. de , Zee S.E.A.T.M. van der , Riemsdijk W.H. van
Published: June 2020

Soil has many functions in sustaining life. The prerequisite conditions for proper soil functioning may be expessed in terms of quality. Chemical quality of soil is predominantly determined by behaviour of compounds in soil. Compound behaviour is the result of the interactions of properties of the compounds and of the soil system under consideration. These can satisfactorily be described by applying methodical rules as derived in soil chemistry and soil physics. This is elaborated with examples referring to the static situation prevailing at adsorptive equilibrium, and to the dynamic situation of compound displacement in soil. The variability of soil properties appears to be of major concern. In these examples, attention is limited to the behaviour of cadmium in soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)
New information of second-generation Landsat satellites for agricultural applications in the Netherlands.
Authors: Epema G.F.
Published: June 2020

Statistical analysis and the construction of reflectance spectra of ground cover types around Wageningen were used to compare the enhanced spectral information of Landsat Thematic Mapper (TM) satellites with information provided by 1st-generation Landsat MSS. TM band 5 was a useful addition to the normal information in the range of visible and near-infrared light, because some crops had a larger decrease in reflectance than others in this band. The low spatial resolution of the thermal band was a major limitation for many applications, although the information was additional to the bands at smaller wavelengths. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Time taken for growing pigs to acclimate to change in ambient temperature.
Authors: Verhagen J.M.F. , Geers R. , Verstegen M.W.A.
Published: June 2020

In 4 almost identical trials, 159 Large White X Dutch Landrace gilts and castrated [male][male], weighing about 20 kg, were housed in groups of 10 and maintained at 15 degrees or 25 degrees C for 12 days; all pigs had previously been maintained at 20 degrees . For pigs maintained at 15 degrees and 25 degrees , daily intake of metabolizable energy averaged 1368+or-62.7 and 1462+or-109.4 kJ.kg-0.75 resp., and daily gain 596+or-28.9 and 622+or-76.8 g; differences between groups were significant. Groups did not differ significantly in heat production or feed conversion efficiency. For pigs housed at 15 degrees , feed intake increased from 1060+or-37.0 g per day at days 2-3 to 1375+or-26.5 g per day at days 11-12. Corresponding values for pigs housed at 25 degrees were 1125+or-29.0 and 1328+or-99.0 g per day. For both groups, heat production was significantly higher in the light than in the dark. Heat production in the light stopped increasing after 8 and 5 days resp. for pigs housed at 15 degrees and 25 degrees ; in the dark it stopped increasing after 6 days for pigs housed at 15 degrees . (Abstract retrieved from CAB Abstracts by CABI’s permission)
Temperature requirements for growth and ripening of apples.
Authors: Kronenberg H.G.
Published: June 2020

The effect of temperature on the growth and ripening of fruits of up to ten cultivars grown at 4 different sites (2 in Netherlands, 1 in German Federal Republic and 1 in Denmark) was studied using a simple model. The period between flowering and harvest could be divided into 3 phases of differing temperature response. In most cases the first month after the beginning of the flowering and the period immediately before harvest showed a positive reaction towards high temperatures. During the period in between, which varied from 1-2 months in early cultivars to 5-6 months in late ones, no temperature effects were found in most cultivars. Temperature sums found in the first and third response periods did not show any relationship with earliness or lateness of crops. On the contrary, early and late cultivars had appoximately the same sums. Base monthly temperatures accounted for 0 to 89% of the differences in days between the different phases of growth of a fruit on the tree. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Quantitative land evaluation of the Chuka-South area, Kenya.
Authors: Veldkamp A.
Published: June 2020

Evaluation of land in the Chuka-South area of central Kenya indicated that there was ample scope for yield increase. Calculated water-limited yield potentials for maize, sorghum, tobacco, cotton, soyabeans, cassava, sweet potatoes, potatoes, rice, Pennisetum americanum, Cajanus cajan and Vigna unguiculata were far above actual yields. Nutrient-limited yield potentials were roughly half the water-limited yield, i.e. natural soil fertility of the Chuka-South area was low. The effects on yield levels of alternative water conservation measures were evaluated for the eastern half of the area. The evaluation indicated that a fair yield increase could be expected from prolonged mulching in the area between 700 and 1000 m. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Development rate, flower growth and production of Anthurium.
Authors: Klapwijk D. , Spek H.J.H. van der
Published: June 2020

Data on leaf plastochron, flower growth and bud abortion in greenhouse-grown A. andreanum were collected from a commercial nursery throughout the year, and additional data were obtained from growers. The leaf plastochron duration was fairly constant from Mar. until Sep. at an average of 72 days. Around 10 Oct. the duration was more than doubled. It then decreased linearly to 72 days again, resulting in high leaf production around Apr. Leaf plastochron seemed to be related to radiation but daylength was probably not involved, as leaf emergence continued during winter. The longest period between flower emergence and flower harvest was around 21 Dec. and the shortest in June-July. Flower production fluctuated strongly, with a minimum in Mar. and a maximum in the second half of June. This maximum was related to the high leaf production in Feb.-Mar. The low production in Mar. was the result of a high abortion rate (near 100%) of flower buds in Dec. The year-round average abortion rate was about 50%. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of day/night humidity and cation ratios and concentration in the nutrient solution on incidence of Didymella bryoniae in glasshouse cucumbers.
Authors: Steekelenburg N.A.M. van , Welles G.W.H.
Published: June 2020

The incidence of the disease on plants and fruits decreased with a lower 24 h av. RH in the range 80-87%. An increase in the electrical conductivity (EC) level of the nutrient solution from 2.5-5.0 dS/m (25 degrees C) decreased the number of diseased leaf axils at a Ca concn of 1.5 mmol/litre by 41%, but had no effect at a Ca concn of 4.5 mmol/litre. An increase in Ca concn from 1.5-4.5 mmol/litre decreased the number of diseased leaf axils at an EC level of 2.5 dS/m by 26%, but had no effect at an EC level of 5.0 dS/m. Changes in EC and Ca concn had no effect on the number of fruits with internal rot. It is concluded that to optimize disease control, high RH, low EC level and low Ca concn in the nutrient solution should be avoided. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Water contents of glasshouse soils at field capacity and at saturation. 1. Relationships between water contents.
Authors: Ende J. van den.
Published: June 2020

The relationship between water contents at saturation and at field capacity was determined in soils from 75 glasshouses in the Netherlands. Sandy, loamy and peaty soils were equally represented.
Water contents of soils at sampling time were found to correspond closely with those at field capacity. Water contents of saturated pastes obtained from field-moist soil samples were higher than those of saturated pastes obtained from soil samples dried previously. For the relationships between water contents of field-moist soil samples and of saturated pastes obtained from field-moist and dried soil samples, correlation coefficients of 0.986 and 0.985, respectively, were found. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Preventing tipburn in chinese cabbage by high relative humidity during the night.
Authors: Berkel N. van
Published: June 2020

Polyethylene sheeting supported on a framework was used in a greenhouse to maintain a high RH over the crop at night so that a root pressure flow could develop. The plants (growing in 1-litre buckets of peat mixed with 5 kg Dolokal (ground magnesium limestone), 500 g PG mix (14 + 16 + 18 + trace elements), and 150 g FTE (fritted trace elements) per msuperscript 3)were watered with nutrient solutions of EC 1.5, 3.0 or 4.5 dS/m (25 degrees C), and half were sprayed with 0.7% Ca(NO3)2. Almost complete prevention of tipburn incidence was obtained where high RH was used with a low EC solution. Calcium spraying did not further decrease tipburn. The technical possibilities of realizing a high night RH in greenhouses are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Transfer of cadmium, lead, mercury and arsenic from feed into tissues of fattening bulls: chemical and pathological data.
Authors: Vreman K. , Veen N.G. van der , Molen E.J. van der , Ruig W.G. de
Published: June 2020

During the last 5 months of the fattening period 16 bulls were given a maize silage and concentrates (2:1) diet containing cadmium 10, lead 10, mercury 0.1 and arsenic 2 mg/kg diet. These concentrations are the maximum permitted in the regulations of the Commodity Board for Feeding Stuffs (1975). Bulls were slaughtered at 500 kg. Cd, Pb, Hg and As concentrations were 6.9, 1.7, 0.08 and 0.17 mg/kg in fresh kidney and 2.6, 0.86, 0.024, and 0.1 mg/kg in fresh liver. Gross and histopathological lesions were not related to intake of heavy metals as 6 bulls given diets without additional heavy metals had similar lesions. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Comparison of two solid-phase markers for measuring the flow of digesta components in the duodenum of sheep.
Authors: Nevel C. van , Demeyer D.
Published: June 2020

The effect of defaunation and refaunation of the rumen of sheep on duodenal passage and rumen digestion was studied. A combination of chromic oxide and polyethylene glycol (PEG) mixed with concentrates was used to estimate intestinal flow. In addition a combination of PEG and Ru-phenanthroline continuously infused in the rumen was used. Differences in flow of duodenal digesta and digesta components, calculated with both marker systems, were rare and small, indicating that Cr2O3 was an adequate marker of the solid phase of the digesta for application of the double-marker method. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Rapid column experiments to study replacement of exchangeable cations in soil samples.
Authors: El-Guindy S. , Harmsen J.
Published: June 2020

A new and rapid soil column technique is described that can verify model calculations on transport and exchange of cations in soil, using equipment for high-performance liquid chromatography (HPLC). Breakthrough curves of cations are presented and compared with results of a model that simulates transport and exchange processes in a soil column. The small column dimensions and the high flow rate allow leaching of individual columns to be completed within one day. Equiulibrium is established almost instantaneously between the leaching solution and the soil in the column. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of reduced fertilizer nitrogen application rates on yield and nitrogen recovery of sugar beet and potatoes.
Authors: Neeteson J.J.
Published: June 2020

Data from 150 sugarbeet and 98 potato field trials in the Netherlands were used to calculate the effects on yield and N recovery of applying 0-90% of recommended N fertilizer rates. Av. sugarbeet root tuber yields were 63.8, 63.5, 62.9, 61.2 and 53.3 t/ha with 100, 90, 75, 50 and 0% of recommended N rate, resp.; corresponding potato tuber yields were 56.8, 56.5, 55.9, 54.4 and 45.1 t. Av. fertilizer N recovery by potato tubers ranged from 33.2% with the recommended N rate to 44.3% with 50% of the recommended N rate. On the assumption that the probability of serious yield deficits should not exceed 5%, current recommended N rates could not be reduced for sugarbeet but could be reduced by 25% for potatoes giving an av. yield deficit of 1.7% and 40% fertilizer N recovery by tubers. The effects of changes in the ratio of fertilizer cost to the price of produce is discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Model calculations of nitrate leaching during the growth period of potatoes.
Authors: Neeteson J.J. , Greenwood D.J. , Draycott A.
Published: June 2020

To estimate the amount of nitrate lost due to leaching during the growth period of potatoes and the amount of mineral nitrogen present in the soil at harvest time, i.e. residual mineral nitrogen, calculations were performed with a previously derived simulation model for the response of potatoes to nitrogen. In the calculations those factors were varied that were considered to affect the amount of nitrate lost due to leaching: precipitation in spring and summer, soil type, mineralization rate of soil organic matter, and amount of fertilizer nitrogen applied. It was calculated that the total loss of nitrogen, i.e. the amounts leached in spring plus the amounts accumulated as residual soil mineral nitrogen, were similar in a loamy sand and a clay loam. The greater loss by leaching from the sand was offset by the greater accumulation of mineral nitrogen in the loam. Under normal conditions of precipitation and mineralization the total loss increased from about 20 kg N/ha at a fertilizer nitrogen application rate of 200 kg N/ha to about 190 kg N/ha at a rate of 400 kg N/ha. At a high rate of mineralization, an application as low as 100 kg fertilizer N/ha resulted in a total loss of about 60 kg N/ha. It was concluded that little nitrate leaching occurs when the current nitrogen fertilizer recommendations are followed, provided that mineralization in the soil proceeds at an average rate. When high mineralization rates are likely to occur, however, the recommendations should be lowered. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Combined effects of dietary restrictions and physical activity on amino acid utilization in rats.
Authors: Maas I.A.M. , Schreurs V.V.A.M. , Weijs P.J.M. , Frings M. , Acker B.A.C. van , Boekholt H.A. , Koopmanschap R.E.
Published: June 2020

Female Wistar rats given protein- or energy-restricted diets or normal unrestricted diets for 1 or 7 weeks were subjected to intensive treadmill exercise. Injections of L-[U-14C]tyrosine, 21 h after the exercise, were used to trace amino acid oxidation and incorporation in tissue proteins of liver, kidneys, soleus muscle and muscles of the upper and lower foreleg. Protein restriction decreased tyrosine oxidation (expressed as percentage of the injected dose), with little effect on the incorporation in tissue proteins. Energy restriction increased tyrosine oxidation and decreased incorporation significantly. With energy restriction, amino acids are probably used to compensate for the lack of energy, resulting in a secondary protein restriction. Treadmill running, in combination with dietary protein and energy restriction, increased tyrosine incorporation in most of the tissues. The results indicate that, under dietary restriction (especially a low-energy normal-protein diet), a single bout of exercise can stimulate protein synthesis, even until 21 h after performance. On all diets the rise in tyrosine incorporation was highest for muscles of the foreleg. Recovery from muscle degeneration, resulting from exercise, might account for the increased protein synthesis. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Estimating the chemical composition of the soil solution of glasshouse soil. 1. Compositions of soil solution and aqueous extracts.
Authors: Ende J. van den
Published: June 2020

Press extracts, saturation extracts and 1:5 by-weight extracts obtained from 75 glasshouse soils were analysed for EC and K, Na, Ca, Mg, NO3, Cl, SO4, HCO3 and P. The analytical data are discussed, with the exception of the HCO3 and P contents of press extracts, as these were much lower than the HCO3 and P contents of equilibrium solutions of the soils. The water-saturated soil pastes from which the saturation extracts were obtained were prepared from both field-moist and air-dry soil. They stood overnight at 25 degrees C before filtration. This overnight storage was unsatisfactory for NO3, as it induced denitrification in the saturated pastes prepared from air-dry soil. Hence, for the determination of NO3, saturation extracts were prepared from air-dry soil, with pastes standing only two hours before filtration. The suspensions from which the 1:5 by-weight extracts were obtained were prepared from air-dry soil and stood overnight at 25 degrees C before filtration. Again overnight storage proved unsatisfactory because of denitrification. Thus, for the determination of NO3, 1:5 suspensions were prepared, this time with a storage period of only two hours. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Hydrology of a tropical rain forest in Surinam.
Authors: Poels R.L.H.
Published: June 2020

Rainfall and discharge were measured for almost 5 years in a 300 ha forested watershed in Surinam. Groundwater levels were measured for 2 years. The hydrological data were used in a simulation model for plant growth. Estimates were made on effective rooting depth, transpiration reduction in the dry season, and the contribution of interception to total water use. Possible relations between hydrological characteristics of the forest and nutrient cycling are given. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Nutrient input and output in undisturbed and silviculturally treated tropical rain forest in Surinam.
Authors: Poels R.L.H.
Published: June 2020

Nutrient inputs and outputs in a catchment area of undisturbed forest were compared with those in a catchment area of silviculturally treated forest in Surinam. Treatment was according to the Celos Silvicultural System. The sustainability of this system on poor tropical soils was tested. Treatment slightly increased nutrient outflow by creek water, but even in the treated area nutrient outflow was still smaller than nutrient inflow by rain water. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of pattern of water supply on Vicia faba L. 1. Dry matter partitioning and yield variability.
Authors: Grashoff C.
Published: June 2020

V. faba cultivars including cv. Minica, Kristall, Alfred and Optica were grown with (a) full irrigation, or restricted irrigation (b) after the start of flowering, (c) after the end of flowering, (d) before flowering or (e) during flowering. Irrigation from the start of flowering stimulated vegetative growth but reduced initial reproductive growth and final seed yield compared with restricted water during flowering only. In 1982-84 using cv. Minica, treatment (e) gave high av. seed yields (7 t/ha), optimum harvest index (0.61 g/g) and a relatively small range of seed yields (2.2 t/ha), while (d) gave 7.1 t/ha, lower harvest index (0.57) and a small range of seed yields (1.4 t/ha). The other treatments and no irrigation gave much lower seed yields and a larger range of seed yields. Treatment (c) gave the lowest harvest index. Similar results were obtained with cv. Alfred. It was concluded that the amount and distribution of rainfall was a major reason for variability in seed yield of this crop. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Detection, causes and consequences of convection currents in bulk-stored grain.
Authors: Uiso C.B.S. , Gough M.C. , Stigter C.J.
Published: June 2020

A simple theoretical model was derived to predict velocities of intergranular cyclic air convection currents in bulk stored grain for a given temp. difference between outer and inner vertical regions of the bulk. Using a tracer gas, the measured airflow in a laboratory simulation was found to be in good agreement with theoretical predictions for differences in the range 17-25 degrees C. In tropical field trials in a metal silo, weather-induced intergranular air convection was detected and quantified in practical bulk storage. Significant m.c. increases, proven here to be due to convective air transported moisture, were observed in the top of the grain bulk in laboratory and field experiments. In both cases, troublesome head space condensation occurred. A new way of reducing observed grain damage due to moisture is proposed and the scope for future academic work indicated. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Contribution to animal nutrition in the Netherlands by the Research Institute for Livestock Feeding and Nutrition, since 1890.
Authors: Honing Y. van der , Langelaar S.J.
Published: June 2020

A State Committee recommended the founding of State Agricultural Experiment Stations (Rijkslandbouwproofstations) in order to keep pace with world trade, particularly in the dairy export trade. Organization and research in nutrition related areas is briefly outlined. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Organic matter digestibility in horses and its prediction.
Authors: Smolders E.A.A. , Steg A. , Hindle V.A.
Published: June 2020

Organic matter (OM) digestibility of 53 feeds was estimated in horses, sheep and in vitro using rumen fluid. Feeds tested were: roughages (grass hay, fresh grass, wilted grass silage, forage maize and artificially dried roughage), compound feeds and compound feed ingredients including cereals. Technical merits of the chosen procedure for digestibility trials with horses are discussed. Horse digestibility data for forages were consistently lower than sheep data, with a variable fibre level effect. For compound feeds and compound feed ingredients horse digestibility was about comparable to sheep digestibility allowing for considerable differences between feeds. In vitro digestibility gave a reliable estimation of OM digestibility in horses for the different group of feeds. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of fibrous and starchy carbohydrates in concentrates as supplements in a herbage-based diet for high-yielding dairy cows.
Authors: Valk H. , Poelhuis H.W.K. , Wentink H.J.
Published: June 2020

The effects of 2 concentrates composed of different carbohydrate sources (beet pulp vs. maize) on intake, digestibility, yield and composition of milk from high-yielding dairy cows given fresh herbage indoors was investigated. In 1988 two diets and in 1989 three diets were used with 9 cows/diet. In 1989 concentrates were supplied on an equal amount of DM and in 1989 on an equal amount of energy. The animals received the concentrates after milking time. In 1988 the experimental period lasted 8 wk and in 1989 10 wk. In 1988 intake of herbage DM tended to be higher on the maize-enriched diet, resulting in a significantly (P
Structural and non-structural carbohydrates in concentrate supplements of silage-based dairy cow rations. 1. Feed intake and milk production.
Authors: Visser H. de , Togt P.L. van der , Tamminga S.
Published: June 2020

A feeding trial was carried out with 64 multiparous dairy cows, in which the effect of type of carbohydrate in concentrate mixtures (starch vs. cell wall constituents) and differences in rumen degradation (fast vs. slow) on feed intake and milk yield were studied. The experiment started immediately after parturition and lasted for 15 wk. The basal diet, which comprised 75% of the total DM intake, consisted of wilted grass silage, maize silage and concentrates. The remaining part of the diet consisted of barley (B), maize (M), pressed ensiled beet pulp (P) or moist ensiled maize bran (MB). All diets were given as totally mixed rations. Total intake of DM and net energy did not differ between diets, but differences were found in energy partition. There was a tendency for cows given diet B to show increased liveweight gain, while cows given P mobilized more body reserves compared with the other treatments. Milk yield did not differ between diets, but milk fat content was higher for diet P. Milk protein content was higher for diets B and M compared with P and MB. The lower protein content of the milk of treatment P can be explained by a longer period of negative energy balance, while the lower milk protein in cows given diet MB probably resulted from reduced microbial protein synthesis. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Apparent digestible phosphorus in the feeding of pigs in relation to availability, requirement and environment. 1. Digestible phosphorus in feedstuffs from plant and animal origin.
Authors: Jongbloed A.W. , Kemme P.A.
Published: June 2020

The digestibility of phosphorus in 15 feeds from plant sources and 8 from animal sources were studied using the total faeces collection technique in 75 trials with pigs 45 to 110 kg in order to match P availability to requirement and thereby reducing excess excretion and hence environmental pollution. Results show that P digestibility in feeds of plant origin varies substantially. For maize, maize byproducts, rice bran and sunflower seed meal P digestibility was low, varying from 10 to 20%. P digestibility of barley, beans (Phaseolus spp.) and soyabean meal solvent extracted ranged from 37 to 39% and dehulled and non-dehulled soyabean meal gave similar results. The highest P digestibility was obtained for wheat and peas, 47 and 45%, respectively. Differences in P digestibility can be explained by the proportion of phytate P and the presence of phytase. P digestibility in feeds of animal origin was high, ranging from 68 to 91%. Differences in P digestibility may be due to differences in technological treatment or physico-chemical structure of the products. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Amino acid requirements of pigs. 2. Requirement for apparent digestible threonine of young pigs.
Authors: Schutte J.B. , Bosch M.W. , Lenis N.P. , Jong J. de , Diepen J.T.M. van
Published: June 2020

In 6 trials with 460 pigs, initially about 19 kg the threonine requirement for growth between about 20 to 40 kg was investigated. To a negative control diet, containing crude protein 160 g and threonine 5.6 g/kg. L-threonine 0.0, 0.6, 1.2 and 1.8 g/kg, was added and compared with a positive control diet with crude protein 185 g/kg and threonine 6.8 g/kg. The negative control diet was supplemented with lysine, methionine, tryptophan, isoleucine, histidine and valine so that no other amino acids than threonine were limiting. The positive control diet was supplemented with lysine and methionine. The experimental diets were fed ad libitum as pellets. In 2 separate trials, the apparent faecal and ileal digestibility of the amino acids of the 2 control diets was estimated. The requirement for total threonine was 7.1 g/kg for maximum weight gain, and 7.4 g/kg for maximum efficiency of feed utilization in a diet containing net energy 2290 kcal/kg. These results correspond with 6.2 and 6.5 g/kg faecal digestible and 5.7 and 6.0 g/kg ileal digestible threonine, respectively. Pig performance on the negative control diet supplemented with the first limiting amino acids, was similar to that of the positive control diet. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Potential rice yields in future weather conditions in different parts of Asia.
Authors: Jansen D.M.
Published: June 2020

The effects of future climate change on potential yields of rice cv. IR36 grown at present and in 2020 and 2100 in China, India, Indonesia, Thailand and South Korea were estimated using the crop growth simulation model MACROS which combines the effects of temp., radiation, wind speed, air humidity and crop status on physiological processes. Historic weather data of these sites were adapted to possible changes in temp. and CO2 level, to mimic climate change. Simulated yields rose in low and middle temp. change scenarios, but decreased in the high temp. scenario. Water use efficiency decreased in the high temp. scenario irrespective of CO2 scenario, and increased otherwise. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Role of sociologists and cultural anthropologists in the development, adaptation and transfer of new agricultural technologies.
Authors: Dusseldorp D.B.W.M. van , Box L.
Published: June 2020

Despite the amount of discussion on the role of sociology and anthropology in agricultural research over the last two decades, the number of sociologists in agricultural research stations is still remarkably low. On the basis of recent literature and two research projects in the Dominican Republic and the Philippines, the potential roles and placement of sociologists in agricultural research are elaborated. The roles discussed are those of trainer/sensitizer, provider of methods, go-between/translator, monitor/evaluator, assessor of social impact, analyser of the creation and use of indigenous knowledge, accommodator, scout, developer of group technologies, and analyser of the functioning of agricultural research. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Sodium chloride salinity in fruit vegetable crops in soilless culture.
Authors: Sonneveld C. , Burg A.M.M. van der
Published: June 2020

Tomatoes, cucumbers and sweet peppers (capsicums) were grown in hydroponic systems in which the nutrient solutions were recirculated. The EC of the nutrient solution was maintained at values of 2.5, 3.7 or 5.2 dS m-1 (25 degrees C) in the different treatments. In some of the treatments, the EC values mentioned were achieved by addition of nutrients, and in others by addition of a combination of nutrients and NaCl. Yields of all 3 crops were adversely affected by increased EC values. Most fruit quality characteristics, on the contrary, were favourably affected. However, the incidence of blossom-end rot in tomatoes and capsicums increased at higher EC values. For capsicums, this was especially the case with NaCl addition. Apart from that, only slight specific NaCl effects were noticed. Salinity threshold values for the different crops lay between 2.3 and 3.5 dS m-1 and salinity yield decrease values ranged from 2.3 to 7.6% for each dS m-1. The absorption of Na and Cl differed with crop and with the Na and Cl concentration. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Weather indices of agricultural production in the Netherlands 1948-1989. 1. General methodology and the arable sector.
Authors: Oskam A.J.
Published: June 2020

The methodology of deriving weather indices for different types of agricultural production is outlined. The indices so derived should be useful for economic research. Indices are derived for wheat, barley, oats, rye, culinary potatoes, industrial potatoes, sugarbeet, legume crops, oilseed rape, flax, fodder beet and silage maize in the Netherlands for each year from 1948 to 1989. The most extreme variations in the indices were
Re-thinking erosion on Java.
Authors: Diemont W.H. , Smiet A. , Nurdin N.
Published: June 2020

Although the unproductive uplands ('dead lands') in Java are now reafforested or terraced, the crop productivity is still low in particular on volcanic soils. Sources of erosion are briefly discussed. It was concluded that the low productivity of upland farming systems was caused by low inputs and not by surface erosion and a redirection of soil conservation policy, planning and research is required. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of pattern of water supply on Vicia faba L. 3. Plant water relations, expansive growth and stomatal reactions.
Authors: Grashoff C. , Verkerke D.R.
Published: June 2020

Faba beans cv. Minica, Wierboon, Kristall, Felix, Optica and Alfred grown in the field in the Netherlands were irrigated to near field capacity, or water stressed, between the onset of flowering and the end of the growing season. Leaf water potential ( psi ), osmotic potential ( pi ) and turgor (P) were linearly related to leaf relative water content (RWC) with no significant differences between cultivars. At full turgor, pi hardly differed between water supply treatments, and the slopes of pi vs. RWC were not significantly different between treatments, indicating the absence of osmotic adjustment. Water supply did not affect the slope of P vs. RWC, and it was concluded that the faba bean cultivars lacked mechanisms to keep P high during water stress. Internode growth during flowering was 2-3 times greater in the well watered than in the stressed treatment. In greenhouse studies with cv. Minica, vegetative growth decreased linearly with decreasing P. Maximum stomatal conductance in the field decreased with psi from an estimated maximum level of 1.0 s/cm (at full turgidity and light intensity >800 micro E/msuperscript 2 per s), following a negative exponential curve. It was concluded that vegetative (expansive) growth decreases faster with decreasing P or psi than the stomatal conductance (and most probably faster than the rate of photosynthesis). It is suggested that this result may help to explain the positive effect of mild water stress on reproductive growth in faba beans. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Nutritional characteristics of cattle forage plants in the eutrophic nature reserve Oostvaardersplassen, Netherlands.
Authors: Vulink J.T. , Drost H.J.
Published: June 2020

During 1982-88 the nutritional value of the main cattle forage plants in the terrestrial part of the eutrophic wetland, the Oostvaardersplassen (dominated by Phragmites australis and Cirsium arvense, with small amounts of Urtica dioica, Poa trivialis and Salix spp.) was studied. Cattle diets were dominated by grass in early summer and autumn, P. australis in July and Aug., and browse in winter. DOM content and the chemical composition of the forage classes grasses, reed, forbs and browse varied seasonally. The DOM content of all forage classes decreased from spring to winter. However, the assumed minimum energy content for cattle maintenance (about 450 g DOM/kg DM) was reached at different moments in the different forage classes. Reed reached it in autumn, grasses in winter, forbs (living parts) remained the entire year above this level and browse remained the entire year below this level. Grazing delayed the maturation of P. trivialis, P. australis and U. dioica. The protein, K, Ca, P, Cu content of the 4 forage classes exceeded the cattle maintenance levels for these nutrients the whole year. The Na and Mg content of grasses, reed and browse were marginal in some periods of the year. Due to their high mineral contents, the forbs were an important mineral source in cattle diets. When compared with data from oligotrophic and mesotrophic habitats, the Poa-Phragmites eutrophic habitat offered comparable feed quality in spring, summer and autumn, but was inferior in winter. (Abstract retrieved from CAB Abstracts by CABI’s permission)