bluuebunny/crossref_metadata_2025 huggingface dataset:
Behaviour of veal calves in individual crates and in group pens.
Authors: Wilt J.G. de
Published: June 2020

The differences in behaviour between calves in the two housing systems are discussed with regard to animal welfare. The behaviour of each calf was recorded by direct observation every 10 mins. over a 24 h period in weeks 8, 12, 16 and 20 after arrival for fattening at approx. 1 week. Lying posture, licking, head butting, mounting, intersucking and urine drinking were monitored. Group housing is seen as an important step towards improved calf welfare. This paper is based on part of a doctoral thesis published by IMAG and available in printed form and on microfiche from: NARD, c/o Pudoc, P.O. Box 4, 6700 AA Wageningen, Netherlands. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Current perspectives on integrated control of some soil-borne diseases and pests of potato in the Netherlands.
Authors: Brussaard L.
Published: June 2020

The current status and prospects of biological control methods and the application of certain crop varieties and cultural methods to prevent and control yield depressions and some soil-borne diseases, including Pseudomonas and Rhizoctonia solani, and nematodes (Globodera spp.) of potato in the Netherlands are evaluated. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Morphology, genesis, and distribution of calcareous material in Late Weichselian sediments of the Rhine and Meuse rivers in the eastern part of the Netherlands.
Authors: Jongmans A.G. , Miedema R.
Published: June 2020

In Late Weichselian sediments of the rivers Rhine and Meuse locally and haphazardly calcareous sediments were deposited. Field investigation of a cross section through a calcareous sediment and subsequent micromorphological investigation of biological activity, decalcification and clay illuviation indicate that such local occurrences are slabs of frozen, calcareous sediments, transported and redeposited as floes during periglacial conditions. Sedimentation of the calcareous material is probably of Bolling age and was accompanied by bioturbation. Decalcification, transport and resedimentation as floes occurred during the Old Dryas. Early in the Allerod the material was strongly bioturbated. Clay illuviation should be dated in the Young Dryas and gley and pseudogley formation, finally, in the Holocene. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Environmental effects on flowering characteristics and kernel set of maize (Zea mays L.).
Authors: Struik P.C. , Doorgeest M. , Boonman J.G.
Published: June 2020

In a phytotron experiment, two hybrids of maize (LG 11 and Bastion) were exposed to different levels of temp., heat around noon, photoperiod and water supply at certain stages of development. Treatment influenced the flowering biology, but hardly affected leaf number. High temp. from tassel initiation until grain set increased the rate of development, but shortened the duration of pollen shedding; the interval between pollen shedding and silking was much longer. Thus the exposure of silks to pollen was curtailed. Grain set in the uppermost ear was hampered. The effect of extra heat from tassel emergence until grain set was minor. Long days from tassel initiation to tassel emergence delayed silking more than anthesis, thus increasing the desynchronization. Long photoperiods shortened the duration of the pollination period, but increased the number of female spikelets and the numbers of grains. Drought from tassel emergence until grain set delayed anthesis by 1-2 d and silking by 4 d. Drought did not consistently reduce the duration of pollen shedding, but impeded grain set. Many interactions between environmental factors and/or hybrid proved to be significant. Variation in number of female florets was partly explained by desynchronization of inflorescences. There was a highly significant (rsuperscript 2 = 0.64; n = 32) simple positive correlation between relative grain set and duration of the period of pollination of the silks by the plant's own pollen. The scatter around this relationship was mainly due to the effects of water availability on the functionality of male and female florets. The final number of grains was correlated closely with the desynchronization, although this relationship depended on hybrid and photoperiod. The environmental effects that influence flowering of maize are summarized in a simplified model of the dynamics of anthesis and silking. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Active immunization against somatostatin increases milk yield in goats.
Authors: Garssen G.J. , Welling A.M.A.W. , Spencer G.S.G.
Published: June 2020

Six Dutch white goats were immunized against a conjugate of somatostatin and human serum alpha -globulin during the 10th week of gestation and again 15 weeks later (in 4th wk of lactation). Six control goats were immunized against the globulin only. Milk yield over first 10 weeks of lactation for treated and control goats was 288.9+or-11.2 and 265.1+or-15.3 kg (mean+or-s.e.) resp. Weekly yields were significantly different during the 1st and 3rd wk (P
Effects of drainage on the botanical richness of peat grassland.
Authors: Strien A.J. van , Melman T.C.P.
Published: June 2020

Data on botanical composition from 3 studies involving drainage of peat grasslands in 1940-75 were reanalysed by means of analysis of variance using total number of plant species, number of quality-indicating species and a system in which species were weighted according to rarity and rate of decline. Alopecurus geniculatus, Glyceria fluitans and Phalaris arundinacea were used as moisture indicators, and Dactylis glomerata and Poa pratensis as drought indicators. On extensively exploited grasslands drainage alone had considerable adverse effects on species richness whereas on intensively managed grasslands the N supply had the dominant effect. Results indicated that there was little or no advantage to nature conservation in omitting drainage where grassland was intensively managed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of CO₂ enrichment on growth of faba beans at two levels of water supply.
Authors: Goudriaan J. , Bijlsma R.J.
Published: June 2020

In greenhouse pot trials, Vicia faba was grown at 350 or 700 cmsuperscript 3 CO2/msuperscript 3 from 17 May to 31 Aug. 1982 and water was withheld in early July. CO2 increased photosynthesis and delayed senescence. The beneficial effect of CO2 on growth was maintained during water stress. The effects of additional CO2 and water were multiplicative. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Cadmium and lead in soils and crops from allotment gardens in the Netherlands.
Authors: Lune P. van
Published: June 2020

Soils and crops from 57 allotment gardens in possibly contaminated areas of the Netherlands were analysed for Cd and Pb. The median Cd and Pb concentrations in the soil samples were higher than those in soils used for arable farming and horticulture. Cd and Pb concentrations in the crops were normal, however. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Heavy metal complexation by surfaces and humic acids: a brief discourse on assessment by acidimetric titration.
Authors: Wang Z.J. , Stumm W.
Published: June 2020

In natural waters the form of occurrence of heavy metal ions needs to be known to understand the factors that control their concentrations, their reactivity and bioavailability. In natural samples, it is difficult to identify the species present and to distinguish between dissolved and particulate concentrations, because of the lack of sufficiently sensitive and specific analytical detectors. It is suggested that the voltammetric measurement of the labile metal ion concentration as a function of pH (from an acidimetric titration of a natural sample) may provide useful information on the pH-dependent distribution of soluble and particulate concentrations and on the stability of (surface and solute) complexes formed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Adsorption of aluminium ions by montmorillonite: influence on aluminium speciation.
Authors: Bruggenwert M.G.M. , Keizer P. , Koorevaar P.
Published: June 2020

A model describes the effect of sorption, charge-determined selectivity and chemical equilibria among aluminium species on the aluminium-clay interaction. The model fits the results of an experiment, involving adsorption of aluminium onto sodium montmorillonite and explains apparently contradictory experimental results about aluminium-clay interaction described in the literature. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Modelling pesticide transport with a three-site sorption sub-model: a field test.
Authors: Boesten J.J.T.I.
Published: June 2020

Field measurements of the behaviour of the nematicide ethoprophos in the winter half-year were used to test a previously developed transport model in three soil types. In the model, the liquid phase is assumed to be homogeneous. The sorption sites are divided into three classes: sorption at class-1 sites is continuously in equilibrium with the liquid phase, whereas sorption equilibration at class-2 and class-3 sites takes place at time scales of days and months, respectively. The model explained the field-measured transport of ethoprophos satisfactorily. The effect of ignoring the long-term sorption equilibration process (i.e. sorption at class-3 sites) on calculated concentration profiles was much smaller than that found in a study reported in the literature for the herbicide cyanazine in a loamy sand soil. It was shown that this difference was related to a difference in the transformation rate coefficient. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Water and salt transport in daily irrigated root zone.
Authors: Dirksen C.
Published: June 2020

With closed, high-frequency irrigation systems, the water supply can be tailored to the instant needs of plants. To be able to do this optimally, it is necessary to understand how plants interact with their environment. To study water uptake under a variety of non-uniform conditions in the root zone, lucerne was grown in laboratory soil columns with automated gamma ray attenuation, tensiometer and salinity sensor equipment to measure soil water contents, pressure potentials and osmotic potentials, respectively. The columns were irrigated with water of different salinity at various frequencies and leaching fractions. This paper presents results obtained in a column irrigated daily with water of conductivity 0.33 S/m (h0 = -13.2 m) at a target leaching fraction of 0.08. This includes the drying and wetting patterns under daily irrigations in deficit and excess of evapotranspiration, respectively. After 230 days the salination of the column had still not reached a steady state. Salinity increased rapidly with depth and root water uptake was shallow for the deep-rooting lucerne. Water and salt transport under daily irrigation cannot be described without taking hysteresis of soil water retention into account. The data presented are suitable for testing various water uptake models, once numerical water and salt transport models of the required complexity are operational. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of wet vs. dry by-product ingredients and addition of branched-chain volatile fatty acids and valerate to dairy diets. 2. Rumen fermentation and milk production.
Authors: Robinson P.H. , Tamminga S. , Vuuren A.M. van
Published: June 2020

Four dairy cows with large rumen cannulae were fed totally mixed diets twice daily. Diets contained equal amounts of hay crop silage and maize silage to a total of about 43% of DM intake. About 35% of DM intake was derived from the by-product ingredients maize gluten feed, beet pulp, and brewers' grains, and the balance was mixed ingredients. Diets were formulated to contain either wet (WET) or dry (DRY) by-product ingredients with (PLUS) or without (MINUS) a supplement containing isobutyrate, 2-methyl butyrate, 3-methyl butyrate, and valerate. Measurements were made from wk 12 to 28 of lactation to determine effects of treatments on feed intake, parameters of rumen fermentation, and milk yield and composition. Milk yield and composition were not influenced by treatments. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of wet vs. dry by-product ingredients and addition of branched-chain volatile fatty acids and valerate to dairy diets. 3. Kinetics of rumen ingesta turnover, whole tract digestibility, and some plasma hormone concentrations.
Authors: Robinson P.H. , Tamminga S. , Vuuren A.M. van
Published: June 2020

Four cows with rumen cannulae were fed twice daily on totally mixed diets containing equal amounts of hay crop silage and maize silage plus a mixture of maize gluten feed, beet pulp and brewers' grains. Diets contained wet ensiled (WET) or dry (DRY) byproduct ingredients without (MINUS) or with (PLUS) a supplement (ISOPLUSReg.) containing the branched-chain volatile fatty acids (isoacids) isobutyrate, 2-methyl butyrate, and 3-methyl butyrate, as well as valerate. Measurements were made from weeks 12 to 28 of lactation to determine effects of treatments on whole tract digestibility, kinetics of rumen ingesta turnover, and plasma concentrations of insulin and somatotropin. Whole tract apparent digestibility of organic (OM) and most OM components was higher with WET diets. Estimated true digestion of dietary nitrogen and OM were also higher (P
Agricultural concepts of roots: from morphogenetic to functional equilibrium between root and shoot growth.
Authors: Noordwijk M. van , Willigen P. de
Published: June 2020

Over the past century, emphasis has changed towards water and nutrient uptake by root system ('functional equilibrium') from relations between root and shoot growth, ('morphogenetic equilibrium'). Separate optima for root growth and shoot growth can often be distinguished. Relatively small root systems can suffice for maximum crop production, provided the supply of water and nutrients is plentiful. Deep tillage or water-table lowering, intended to increase rooting depth, can be counterproductive for plant growth. Larger root systems may, however, withstand rapidly changing environmental conditions better, and may increase nutrient use efficiency or reduce nutrient loss. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effects of soil acidity on Douglas fir seedlings. 1. Rooting characteristics of natural regeneration of Douglas fir in strongly acid forest soils.
Authors: Smit H.P. , Breemen N. van , Keltjens W.G.
Published: June 2020

Results of field studies suggested that total root length of Douglas fir (Pseudotsuga menziesii) in mineral soil was affected by high exchangeable Al accompanied by low exchangeable Ca. This was only true, however, if the mineral soil to 5 cm depth was extremely acid (pH
Multispectral aerial photography as a supplemental technique in agricultural research.
Authors: Clevers J.G.P.W.
Published: June 2020

Narrow spectral bands in the visible and near IR were tested for use in remote sensing of agricultural field trials. Recordings of high spectral (25-100 nm bandwith), temporal (fortnightly) and spatial (+or-1msuperscript 2) resolution, were obtained using an airborne multispectral photographic (MSP) system. Calibrated reflectance factors of spring barley and spring wheat crops were obtained using atmospheric correction and radiometric calibration for reference targets in the field. LAI were estimated from spectral reflectance characteristics of cereals during the growing season for various treatments such as N nutrition and sowing date. Quantitative information was obtained in an objective and non-destructive mannner with greater precision by MSP than by conventional field sampling. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effect of methionine compounds on rumen activity of cows.
Authors: Huisman J. , Weerden E.J. van , Leeuwen P. van , Koch F.
Published: June 2020

Rate of degradation of hay was studied, using the nylon-bag technique, in 2 cows given a basal diet without (controls) or with a liquid methionine supplement (LiquimethReg.) or a protected methionine supplement (MepronReg.) providing methionine 25 g daily. After 24 and 48 h incubation methionine supplementation significantly increased degradation of DM, organic matter and cell wall constituents compared with controls. Degradability of crude protein (CP) was significantly increased by methionine supplementation, and degradability was affected by type of supplement with degradability of CP greater with the liquid methionine supplement than with the protected methionine supplement. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The influence of slowly and rapidly degradable concentrate protein on nitrogen balance, rumen fermentation pattern and blood parameters in dairy cattle.
Authors: Veen W.A.G. , Veling J. , Bakker Y.T.
Published: June 2020

In a crossover trial, 4 cows were given concentrates containing rapidly and slowly degradable protein in combination with prewilted grass silage. Diets were given in 2 equal daily portions according to DCP and net energy requirements. The trial consisted of 3 main periods of 3 weeks each, with faeces, urine and milk collected and measured during the final week. On 1 day during this week samples of rumen fluid were taken and on 2 days blood samples were taken, directly before the morning feed and 1, 2, 3, 4 and 8 h later. N digestibity and N retention were the same on both rations. A concentrate with slowly-degradable protein resulted in a significantly higher rumen pH and acetate:propionate ratio. Ammonia concn. tended to be lower. Slowly-degradable concentrate protein led to a significantly higher concn. of urea and a lower concn. of insulin in blood. The concn. of several of the essential amino acids, and of the glucogenic amino acids and glycine was significantly lower. There were no significant effects of type of protein on milk yield or milk composition, but there was a tendency for these parameters to increase with ration containing slowly-degradable protein. Results suggest the ration containing slowly-degradable concentrate protein produced a more even rumen fermentation, which promoted a higher acetate:propionate ration in the rumen. On this ration there was a tendency for more gluconeogenesis from amino acids to occur. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The modelling of growth in the pig.
Authors: Moughan P.J. , Verstegen M.W.A.
Published: June 2020

The modelling of growth in the pig is reviewed, with particular reference to the schematic approach developed by the authors and others, in which growth is modelled from the supply of digested amino acids and the intake of protein-free energy. Potential gains in protein and fat content are used to calculate body weight gain, body composition and carcass composition. It is suggested that future models should be more deductive and less empirical than present models, and that it may be possible to describe the control of gains in fat and protein content in terms of cellular activity. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Measurement and simulation of crop photosynthesis of cucumber (Cucumis sativus L.) in greenhouses.
Authors: Nederhoff E.M. , Gijzen J.G. , Vegter J.
Published: June 2020

Short-term photosynthesis measurements were performed in a cucumber crop in 3 experimental greenhouse compartments. The greenhouse was used as a measuring cuvette for the whole canopy. The calculated CO2 balance of the greenhouse was based on measurements of CO2 concentrations inside and outside, combined with on-line measurement of the ventilation rate. The method is fully described and results for 3 characteristic days are presented. Positive correlations were found between photosynthesis rate and both radiation and CO2 concentration. When measured environmental conditions were used as input data for a simulation model, the simulated and measured rates of photosynthesis generally showed a close similarity. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Water contents of glasshouse soils at field capacity and at saturation. 2. Estimating water contents from organic-matter and clay contents or from loss-on-ignition.
Authors: Ende J. van den.
Published: June 2020

Water contents of soils at field capacity and at saturation could be accurately estimated with the use of regression equations in which loss-on-ignition was the independent variable. Multiple regression equations in which organic-matter and clay contents were the independent variables did not have a higher predictive value. The regression coefficients in equations for estimating water contents of saturated pastes obtained from air-dry soil samples amount to about 80% of the corresponding coefficients for saturated pastes obtained from field-moist soil samples. The clay fractions were found to contribute much more to the water contents of saturated soil pastes than to those of soils at field capacity. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of day temperature and salt concentration on the incidence of sponginess in radish tubers (Raphanus sativus L.).
Authors: Heij G. , Kobryn J.
Published: June 2020

Sponginess in radishes, cv. Novired, was studied in greenhouse pot experiments at different EC levels (1, 4 and 8 dS/m, 25 degrees C) of the nutrient solution applied and at 5/7 degrees and 5/12 degrees C temperatures. Increased EC and a low daytime temperature reduced the incidence of sponginess. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Nitrogen fertilization of grass seed crops as related to soil mineral nutrition.
Authors: Meijer W.J.M. , Vreeke S.
Published: June 2020

The relationship between the level of soil mineral N present in early spring and the economically optimum application rate of N fertilizer was investigated in field experiments in 1978-84 at 4 locations in the Netherlands with Lolium perenne, Poa pratensis and Festuca rubra. Spring dressings, as split and single applications, of 30-210 kg N/ha and autumn dressings of 0-90 kg N/ha were used. The optimum spring rates were linearly related to mineral N in the 0-90 cm soil layers in L. perenne. No such relationship existed for the other species. The economically optimum spring N rates were 110 and 84 kg/ha, and yields were highest with autumn N dressings of 60 and 30 kg/ha for P. pratensis and F. rubra, resp. Autumn dressing had no effect on L. perenne if the spring dressing was near or above the optimum. A split spring dressing produced greater vegetative regrowth and reduced yields. Seed yield responses to fertilization were related to number of inflorescences produced rather than weight of seed per inflorescence. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Impact of wild geese on grasslands in the Netherlands.
Authors: Bruinderink G.W.T.A.G.
Published: June 2020

This synopsis, based on a Ph.D. thesis, evaluates the impact of grazing, treading and manuring by wintering geese on yields of Lolium swards studied in Friesland in 1983-85. The implications of yield losses for dairy farming are discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Differences between genotypes of tomato (Lycopersicon esculentum Mill.) in net photosynthesis, light absorption by leaves, chlorophyll content and specific leaf fresh weight under low-energy conditions.
Authors: Nieuwhof M. , Dijk S.J. van de
Published: June 2020

Differences in net photosynthesis between tomato genotypes, grown under low light intensity and, from day 30, at 3 night temperatures, were largely due to differences in the capacity of the leaves to absorb light. Variation in chlorophyll content and leaf thickness largely explained the differences in light absorption. Genotypes with large thin leaves and a high chlorophyll content were thought to be best adapted to low-energy conditions. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Epidemiological and economic evaluation of foot-and-mouth disease control strategies in the Netherlands.
Authors: Dijkhuizen A.A.
Published: June 2020

A Markov chain model for a microcomputer is described in which the economic aspects of control strategies for foot-and-mouth disease in cattle and pig herds can be examined. Epidemiologically, the most favourable results for the Netherlands were obtained using the current strategy: annual vaccination of cattle combined with slaughtering of affected herds and ring vaccination. However, it is suggested that annual costs could be reduced considerably by ceasing routine prophylactic vaccination, provided that adequate measures are taken when outbreaks occur. It is concluded that the increased risk of export bans, not yet included in this simulation model, is unlikely to outweigh the benefits of reducing annual direct costs. All pathways and control strategy, cost elements and default values included in the model are tabulated as are the probable epidemiology during an outbreak, secondary outbreaks, total direct economic losses per outbreak and per year, and a results sensitivity analysis. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Determination and analysis of the economic optimum culling strategy in swine breeding herds in Western Europe and the USA.
Authors: Scholman G.J. , Dijkhuizen A.A.
Published: June 2020

Optimal sow culling strategies were compared for the Netherlands, Belgium, UK, Denmark, German Federal Republic and the USA. The annual sow replacement rate for the 6 countries averaged 47, 57, 39, 49, 50 and 59% resp. The net present value of the total extra profits (termed retention pay-off; RPO) to be expected from keeping a sow until an optimal parity (estimated using the PorkCHOP economic replacement model) instead of replacing her immediately is tabulated for parities 1, 2, 3, 5, 7 and 9 for each country. In the Netherlands, Belgium, the UK and USA, sows of av. merit had a small positive RPO index after 9 parities, indicating an economic optimal lifespan of 10 parities. In Denmark and the German Federal Republic, the optimal lifespan was 6 and 7 parities resp. The loss in income due to delayed conception (since fewer pigs can be sold) was highest in Denmark and the USA (both Dfl 4.80 per extra day open), and lowest in Belgium and the UK (Dfl 3.35 and Dfl 3.33 resp.). For all countries, the more favourable the ratio of slaughter price of culled sows:cost of replacements, then the shorter was the optimal herd life. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The use of social science methods in agricultural research: the case of late transplanting of rice in the Dominican Republic.
Authors: Doorman E.
Published: June 2020

This article aims to show how social science methods can be combined with agronomic research to yield information directly relevant to the development of agricultural technology for small farmers. First, problems identification and definition are worked out through reconnaissance and case studies. Then, quantitative estimates of the prevalence and impact of those problems can be obtained through the execution of a survey and trials. The combination of qualitative and quantitative methods can result in a substantial change in outlook on a specific problem, as is indicated for the case of rice tranplanting in the Dominican Republic. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effects of light intensity on nitrogen economy of spring barley (Hordeum distichum L.).
Authors: Ellen J. , Oene H. van
Published: June 2020

In a pot experiment in a phytotron, barley cv. Trumpf seedlings were grown at a light intensity of 6.50 MJ/msuperscript 2 for 40 d and then at light intensities of 6.50, 4.33 or 1.86 MJ/msuperscript 2 with a 14-h day. 134 mg N/plant was applied in 3 dressings at 2 d before emergence and 26 and 48 d after emergence. N uptake was only slightly affected by light intensity. DM yield/plant increased with increasing light intensity. 101 mg DM/mg N was obtained at a light intensity of 1.86 MJ/msuperscript 2 and 175 mg DM/mg N at 6.50 MJ. Higher light intensity accelerated leaf senescence and shortened the photosynthetically active period by restricting N concn. N harvest index was reduced at the lowest light intensity. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Application of linear and non-linear P-sorption models for describing phosphate transport.
Authors: Zee S.E.A.T.M. van der , Leus F. , Louer M.J.P.F.
Published: June 2020

Phosphate transport in small columns was described using a two-site linear sorption model and a non-linear adsorption-precipitation model. Both approaches gave reasonable to good agreement with experimental breakthrough curves. This indicates the applicability of the simple linear model for engineering purposes, besides the general use of the more complex non-linear model. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Tritiated hay and chromium-mordanted neutral-detergent fibre as particulate markers for digesta kinetics in the reticulo-rumen.
Authors: Bruchem J. van , Kamphuis F. , Janssen I. , Lammers-Wienhoven S.C.W. , Bangma G.A. , Hoek J. van den
Published: June 2020

Third cut wilted grass was ensiled and fed to 4 rumen cannulated Texel wethers at 883 or 1248 g DM daily in 6 equal portions with 4-h intervals. Passage of the reticulo-ruminal particulate phase to the lower gut was estimated with chromium-mordanted neutral-detergent fibre (CrNDF) and tritium-labelled hay as markers, the latter subject to both passage and reticulo-ruminal degradation. Fractional passage rates (kp) were deduced from faecal marker excretion curves. For CrNDF and tritium, kp averaged 2.44 (s.e.m. 0.19) and 3.38 (s.e.m. 0.20) %/h, respectively; difference was significant. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Dried beet pulp, pressed beet pulp and maize silage as substitutes for concentrates in dairy cow rations. 1. Feeding value, feed intake, milk production and milk composition.
Authors: Visser H. de , Hindle V.A.
Published: June 2020

A feeding trial was carried out with 48 dairy cows in 2nd or later lactation. The experiment started immediately after parturition and lasted for 13 wk. Basal diets consisted of a mixture of artificially dried grass and maize silage as roughage components, and concentrates based on a mixture of byproduct feeds. In addition to the basal diet, dried beet pulp, ensiled pressed beet pulp or maize silage was given. Two groups received either dried beet pulp (DP) or ensiled pressed beet pulp (PP). The 3rd group received extra maize silage (M). All rations were given as totally mixed rations to prevent selection. Digestibility of the ration components was determined by in vitro and in vivo methods. The feeding value of both types of beet pulp and maize silages was in agreement with that reported in literature. Total DM intake differed significantly between DP and the other groups (PP and M). Energy intake was highest for DP and lowest for group M. Milk yield was similar for all groups. However, group PP displayed an apparently different pattern, with higher peak production than group M. Fat content and fat yield were similar for all groups. Milk protein yield did not differ significantly between groups, but group M tended to have the lowest production. Milk protein percentage did not differ between the groups, although group M was usually lowest. The calculated energy balance was in agreement with liveweight changes. (Abstract retrieved from CAB Abstracts by CABI’s permission)
The Institute for Soil Fertility Research 1890-1990.
Authors: Harmsen K.
Published: June 2020

This paper presents a brief overview of the history of the Netherlands Institute for Soil Fertility Research. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Nitrogen cycling in high-input versus reduced-input arable farming.
Authors: Faassen H.G. van , Lebbink G.
Published: June 2020

A comparison was made between a high-input and two reduced-input farming systems using a rotation of winter wheat-sugarbeet-spring barley-potatoes on a calcareous silt loam soil. Nitrogen balance sheets for the growing seasons of 1986-1988 showed N deficits of 0-170 kg/ha, suggesting substantial N losses to the environment. The uncertainty about actual N losses mainly depended on the uncertainty of estimated net N mineralization. Periods with much rainfall in 1987 and 1988, inappropriate use of animal manure and soil compaction may partly account for the heavy N losses in all three farming systems. Potential rates of N-cycling processes were studied over the years to observe effects of changes in management. To increase the efficiency of mineral and organic N inputs, and to decrease N losses, soil inorganic-N concentrations should be kept low, especially during periods when losses are likely to occur. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A simple model of P uptake by crops as a possible basis for P fertilizer recommendations.
Authors: Noordwijk M. van , Willigen P. de , Ehlert P.A.I.
Published: June 2020

In the Netherlands the Pw value, based on an extraction of soil P with water, is used as a basis for P-fertilizer recommendations for arable crops. Using a simple, mechanistic model of P transport in the soil the Pw value required for adequate P uptake by crops can be calculated on the basis of daily uptake requirements, root area index, P-adsorption isotherms and total amount of P taken up during a growing season. Calculated Pw values for adequate uptake are in the same range as the present recommendation scheme based on field experiments. Possible refinements of the model are discussed. For each soil the Pw value can be calculated that corresponds to the P concentrations in the soil solution according to standards set to reduce environmental pollution. The model predicts that, unless the root area index of non-cereal crops is considerably improved, these standards cannot be met in the plough layer without affecting crop production levels. Calculations show that the present method of determining the Pw value yields a reasonable compromise between a measurement of intensity and capacity of P supply in the soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Determination of mass balances and ionic balances in animal manure.
Authors: Japenga J. , Harmsen K.
Published: June 2020

Liquid and solid fractions of three different pig slurry samples and a poultry manure sample were isolated through high speed centrifugation followed by ultrafiltration. The gross ionic composition of the liquid manure fractions could be described by: K+, Na+, Ca2+, Mg2+, Cl-, bicarbonate, weakly acidic cations (ammonium) and weakly alkaline anions (acetate). Ionic balances showed an agreement of more than 98% between anionic ad cationic species. The elemental composition of a pig slurry solid fraction was determined. Mass calculations based on this analysis accounted for 98% of the total weight. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Comparison of the content of clostridial spores in wilted grass silage ensiled in either laboratory, pilot-scale or farm silos.
Authors: Spoelstra S.F.
Published: June 2020

Fifty-two laboratory silages (1.5 litres), 108 samples of pilot-scale silos (2-4 t) and 167 samples of farm silages were analysed for clostridial spore contents, proximate composition and concn of fermentation products. Numbers of clostridial spores ranged from 100 to 10 million/g. Relationships between spore counts as dependent variable and DM, butyric acid and ammonia-N contents as independent variables were established for the 3 silage types by regression analyses. Similarity existed in the relationships for pilot-scale and farm silages, showing a gradual drop of spore counts with higher DM levels. Laboratory silages showed either a pronounced clostridial fermentation with high levels of butyric acid, ammonium-N and spores or no clostridial fermentation at all. In contrast to the larger-scale silages, no clostridial fermentation was found at DM contents above 250 g/kg. In laboratory and in pilot-scale silages about 60% of the variation in spore count could be explained from either the butyric acid or ammonia content. In farm silages this figure dropped to 20-30% and it was concluded that the chemical parameters cannot be used to predict spore counts in farm silages. The differences between the larger scale silages and laboratory silages are attributed to the heterogeneity of the pilot-scale and farm silages. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Comparison of multivariate calibration methods for prediction of feeding value by near infrared reflectance spectroscopy.
Authors: Goedhart P.W.
Published: June 2020

The spectrum of absorbance of near infrared spectroscopy (NIR) measurements contains indirect, non-specific information about the feeding value of the feed sample and can be used to predict this value. A linear calibration model was estimated from experimental data and a model was used to predict unknown in vitro values with measured spectra in future samples. Multicolinearity in the NIR measurements occurs frequently. Inclusion of all absorbances in a calibration model leads to complications and large prediction errors. To overcome multicollinearity several methods were proposed. The methods are described and applied to data in which in vitro digestibility of organic matter of maize for cattle was predicted by means of absorbances measured at 351 wavelengths. Comparison of methods showed that for these data Partial Least Squares was the best method. Multiplicative scatter correction of the spectra prior to estimation gave better predictions for all methods. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Estimation of dry matter yield of silage by means of multispectral aerial photography.
Authors: Clevers J.G.P.W. , Sibma L.
Published: June 2020

The near-infrared reflectance of maize crops grown in East Flevoland, Netherlands, estimated using aerial photography was used to estimate LAI. By analysing a calibration set, a regression function of DM yield on near-infrared reflectance factor was estimated. This regression function was used to estimate DM yield of maize grown under similar conditions and photographed on the same day. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Temperature effects on anatomy and digestibility of leaf and stem of tropical and temperate forage species.
Authors: Wilson J.R. , Deinum B. , Engels F.M.
Published: June 2020

Growth temp. effects on anatomy and digestibility of leaf and stem of tropical and temperate forage species (Cynodon dactylon, Panicum maximum var. trichoglume, P. laxum, Lolium perenne and Medicago sativa), representing a range of anatomical types, was evaluated. Plants were grown in controlled-environment greenhouses at day/night temp. of 32/26 or 22/16 degrees C. Tissues of defined development stage were sampled for analysis of proportion of cell types, cell wall thickness, staining properties and digestion, using transverse sections on microscope slides immersed in rumen fluid. Leaf and stem harvested from whole plant tops was analysed for OM digestibility (OMD), cell wall digestibility (DCW), lignin, cell wall and insoluble ash. Temp. had little consistent effect on the proportion of different cell types, or the thickness of cell walls, cell wall content or insoluble ash. The digestion of the walls of sclerenchyma, bundle sheath and xylem cells was lower in tissues grown at the higher temp., especially for leaf. High temp. decreased OMD by an average of 6.6 percentage units for leaf and 12.4 percentage units for stem in the grasses, and by 2.6 percentage units for both tissues in M. sativa. The decrease in OMD and DCW with high temp. (excluding stem of M. sativa) was correlated with increase in lignin concn. High temp. appeared to increase the intensity of lignification of the existing lignified cells rather than increase the proportion of cells becoming lignified. Staining intensity was an insensitive indicator of this change in lignification. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effects of gamma-irradiation of seed potatoes on numbers of stems and tubers.
Authors: Haverkort A.J. , Langerak D.I. , Waart M. van de
Published: June 2020

In field trials with potatoes cv. Bintje, Jaerla and Spunta in which the seed tubers had been treated with gamma -rays from a 60Co source with doses varying from 0.5 to 27 Gy, tuber yield, harvest index and number of stems and tubers were determined. A dose of 3 Gy increased the number of tubers by 30% in Spunta in 2 out of 3 trials and by 17% in one trial in Jaerla, but it did not increase the number of tubers in Bintje. Doses of 9 or 10 Gy did not influence the number of tubers nor stems, and decreased harvest index. A dose of 27 Gy yielded off-type plants with reduced yield and number of tubers. gamma -Radiation affected the growth of the sprout apex, allowing lateral buds or divisions of the affected apex to develop into stems. To achieve larger numbers of tuber-bearing stems, tubers should preferably be irradiated at the start of sprout growth, about 5 months before planting. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Effects of changing land use in the Netherlands on net carbon fixation.
Authors: Wolf J. , Janssen L.H.J.M.
Published: June 2020

The changed crop rotation on arable land, the decreasing grassland area and the increase in forest area in the Netherlands resulted in a decrease in C pool size. For the calculation of this C pool a method requiring only three input data (average amount of crop or tree residue rate, soil organic matter decomposition and the humification coefficient) has been applied. However the method can only be applied to situations in equilibrium where all three input data are equal. For a changing land use a new state of equilibrium and rate of change in C pool size can be calculated. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Some remarks about the soils of the alluvial plain of Iraq, South of Baghdad.
Authors: Buringh P. , Edelman C.H.
Published: June 2020

Soil characteristics of the area surveyed are discussed on the basis of a general soil-association map (I: 250, 000) and a detailed map (I: 50, 000) prepared by means of systematic air-photo analysis. The technique is suitable for mapping large areas with a limited amount of field work. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A field experiment concerning capillary rise of moisture in a heavy clay soil.
Authors: Wind G.P.
Published: June 2020

The rate of capillary rise of moisture in a heavy clay soil was calculated by means of a water balance. This moisture movement supplied about 150 mm in 1953. Under favourable circumstances, a delivery of 3-4 mm per day is possible. The calculated values appeared to be in conformity with the law of unsaturated moisture flow. A graph gives the relationship between height above the water table, pF and capillary rise. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A mineralogical investigation of some Gold Coast soils.
Authors: Hamilton R.
Published: June 2020

The mineralogical compositions of five types of melanites (alkaline, black heavy clays derived from a basic hornblende gneiss) and of alluvial fluviomarine soils (alluvites) from the dry savannah plains east of Accra and of two different groups of brightly coloured soils (rubrites) from the forested hills in Ashanti are tabulated. The ages and transportation of the soils are deduced from their mineralogical composition. (Abstract retrieved from CAB Abstracts by CABI’s permission)
A regional investigation into the relation between soil structure, yield of sugar beets and nitrogen supply.
Authors: Kuipkks H.
Published: June 2020

The influence of soil structure, determined visually, was the same with low and high N dressings. Poor structure was associated with great response to N; yields without N were remarkably low and higher optimum amounts of N were found with poor structures than with favourable ones. Differences in soil structure accounted for only a small part of the variation in N response (4.2-23.5 tons/ha) in old arable fields receiving no manure and pH and sowing date played a part. The structure of the marine-clay soils studied can best be characterized by the amount of large pores. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Observations on the formation and growth of tubers on the potato plant.
Authors: Krijthe N.
Published: June 2020

An account is given of an investigation, to be continued for several years, on the relationship between chitting, number of sprouts on the seed potato and the grading of the harvested potatoes. The influence of the following treatments on tuber growth (one treatment per year) was studied: (1) methods of chitting; (2) size of seed potatoes and (3) storage condition. After the first fortnight's growth, whole, sample plants were lifted weekly to study the position of stolons on the stems, and the location of the largest and smallest tubers on the plant, the size of tuber being judged by its length. At each lifting, the relative positions of the largest, the smallest and of the medium-sized tubers were the same on each plant. These positions were approximately the same in different varieties of potatoes, and the general scheme is shown diagramatically. The treatments (1), (2) and (3) showed no significant effects on formation and growth of tubers provided the sprouts of the seed potatoes were the same length. The phenomenon of secondary-tuber formation is discussed.-D.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Influence of a single non-destructive harvest on potato plantlets grown for minituber production.
Authors: Lommen W.J.M. , Struik P.C.
Published: June 2020

In vitro-propagated potato cv. Ostara and Bintje plantlets were transplanted in a greenhouse at 350 plants/msuperscript 2 under tuber-inducing conditions. Plants growing undisturbed were compared with plants from which tubers >=0.3 g were removed in a single non-destructive harvest 3-8 weeks after transplanting. In undisturbed plants tuber initiation slowed down 4 weeks after transplanting, and an average of 2 tubers/plant (average weight 5 g) were harvested in 11 weeks. After a non-destructive harvest new stolons and tubers were initiated, but overall and tuber growth rates were reduced, probably as a result of the combined effects of tuber removal, root damage and deep replanting. Highest tuber numbers and lowest growth rate reductions occurred when growth was at its maximum. The highest number of tubers/plant (3.44) was achieved with non-destructive harvesting 6 weeks after transplanting, but FW/tuber decreased with delay in harvesting from 1.97 to 0.77 g. Using this non-destructive harvesting procedure >1400 and 2400 minitubers >=0.3 g (average weight 1-2 g) could be produced per msuperscript 2 within 8 and 9 weeks of transplanting by Ostara and Bintje, respectively, and would be suitable for use in large-scale seed tuber production programmes. (Abstract retrieved from CAB Abstracts by CABI’s permission)