Netherlands Journal of Agricultural Science最新文献

{"title":"Analytical growth equations and their Genstat 5 equivalents","authors":"M. Heinen","doi":"10.18174/njas.v47i1.479","DOIUrl":"https://doi.org/10.18174/njas.v47i1.479","url":null,"abstract":"Two ways of representing some of the existing growth functions, (the exponential, the monomolecular or Mitscherlich, the logistic or autocatalytic, the Gompertz, and the Richards equations) are compared. In the first, growth is expressed in the parameters mass at time zero W0, mass at time infinity Wf, and a measure for the relative growth rate k. In the second, different parameters are used because of robust parameter optimization (e.g., by the statistical software package Genstat). The relationships between these fitted parameters and the parameters W0, Wf and k are demonstrated. The properties of these models, such as physical meaning of the parameters, properties at the point of inflection (if it exists), and the growth rate at a limit W -> 0, are examined. The second order exponential polynomial was rewritten in such a way that use was made of a proportionality constant, equal to the relative growth rate at the point of inflection. Application of the growth models is demonstrated using data for lettuce grown in a nutrient film system. Finally, it is shown that, except for the exponential polynomial, all growth equations originate from one single equation.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114492371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of the accessibility of concentrate on the behaviour of cows milked in an automatic milking system","authors":"C. D. Lauwere, A. H. Ipema, J. Metz, J. Noordhuizen, W. Schouten","doi":"10.18174/njas.v47i1.475","DOIUrl":"https://doi.org/10.18174/njas.v47i1.475","url":null,"abstract":"The advantages and disadvantages are discussed of forcing cows to visit the automatic milking parlour regularly by making it the only way for them to obtain supplementary feeds, vs. allowing cows to choose the frequency of their visits to the parlour. An alternative routing method was studied, in which the cows could move freely between the feeding and lying areas, but were stimulated to visit the automatic parlour by making it the only way of accessing the concentrate feeder. Two experiments were conducted, each with 2 treatments and 20 Holstein Friesian dairy cows. In the first treatment of experiment 1, the concentrate feeder was accessible only via the automatic parlour, and in the second treatment of experiment 1, concentrates were freely accessible. In both cases a new portion of concentrate became available once every 2 h. In experiment 2, the concentrate feeder was available only via the automatic parlour. A new portion of concentrate became available every 2 h during the first treatment of this experiment and every 4 h during the second treatment. Results showed that allocation of concentrate in a feeder which can only be reached via the automatic parlour is a good stimulus to attract cows to the parlour on a regular basis, because the milking frequency of these groups increased, and the waiting time in front of the concentrate feeder and the number of aggressive interactions in this area decreased. It is concluded that it is better to make concentrate available once every 4 h than once every 2 h, because this increases concentrate intake and rest in the barn.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131421000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial and temporal dynamics of water in the root environment of potted plants on a flooded bench fertigation system","authors":"W. Otten, P. Raats, R. Baas, H. Challa, P. Kabat","doi":"10.18174/NJAS.V47I1.478","DOIUrl":"https://doi.org/10.18174/NJAS.V47I1.478","url":null,"abstract":"The relationship between evapotranspiration of potted Ficus benjamina plants on a flooded bench fertigation system and the distribution of water in the root zone was studied in detail for a range of fertigation schedules. The physical characteristics of the peat-based potting medium were described by models commonly used in soil physics. The functioning of the substrate in practical situations was greatly affected by hysteresis in the water retention characteristic. Daily evapotranspiration of Ficus benjamina plants ranged from 0.4 to 4.1 kg/msuperscript 2 per day, of which 19-41% was lost by evaporation. Water uptake by plant roots resulted in near hydrostatic equilibrium conditions as long as the volumetric water content was above 0.22. Lower average water contents resulted in locally drier conditions in the root environment. The absorption of water during irrigation depended on the soil physical conditions and increased with decreasing volumetric water content before flooding. The majority of the water absorption occurred within the first minutes, making frequent fertigation more effective than increasing the duration. Actual buffer capacity of the potting medium was defined and by combining measured absorption during flooding with data on evapotranspiration, the derivation of minimum requirements of the fertigation schedule is demonstrated.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130875914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ammonia emission from dairy cow buildings: a review of measurement techniques, influencing factors and possibilities for reduction","authors":"G. Monteny, J. Erisman","doi":"10.18174/njas.v46i3.481","DOIUrl":"https://doi.org/10.18174/njas.v46i3.481","url":null,"abstract":"This study aimed to make an analytical inventory of ammonia emission data of dairy housing systems and to assess possibilities for reduction, based upon the analysis of processes and factors involved in the production and volatilization of ammonia. Mass balance methods for the determination of air exchange rates for naturally ventilated dairy cow buildings that are based upon natural or introduced tracers may have good potential for application in emission studies. Differences occur in housing systems, floor types and manure collection and manure storage systems. Ammonia emission levels for cubicle (loose) houses are higher (20-45 g/day/cow) than for tie stalls (5-27 g/day/cow), and variation in emissions by housing type is large. Integration of knowledge of ammonia emission related processes and factors will support a more detailed analysis of differences and variation, and will allow optimization of possibilities for emission reduction. Substantial emission reductions of up to 50% for cubicle houses with slatted floors can be achieved through each of the following measures: flushing of floors with water or diluted formaldehyde, optimised feeding strategies, and slurry acidification. Highest reductions are possible through V-shaped, solid floors (52%) as a single measure, or in combination with flushing with water (65%) or diluted formaldehyde (80%). Providing that drawbacks are solved, nationwide introduction of one or more these measures will lead to a maximal reduction of the NH3 emission in the Netherlands to 18 kt per year.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132423113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Root, soil water and nitrogen dynamics in a catch crop - soil system in the Wageningen Rhizolab","authors":"A. V. Dam, P. Leffelaar","doi":"10.18174/njas.v46i3.483","DOIUrl":"https://doi.org/10.18174/njas.v46i3.483","url":null,"abstract":"Catch crops (winter rye [Secale cereale] and fodder radish [Raphanus sativus]) were grown on lysimeters with rhizotron facilities in Wageningen, Netherlands, from September-March (1993-94) and August-March (1994-95) in order to study root growth and water and nitrogen dynamics under different regimes of irrigation and N supply. Catch crops took up 20-30 g N/msuperscript 2, of which 37-48% was present in dead leaves in March. Rooting depth increased by 2.6 cm/day for both species at the start of the growing season. Catch cropping reduced the NO-3-N concentration in the soil considerably, initially in the top layers and then further down the soil profile. The reduction in total leached N was similar to the total crop N uptake. Nitrate-N concentrations in leached water were reduced by 49-85 mg/litre (62-99%), depending upon N availability and irrigation. Due to catch cropping the NO-3-N concentration in the percolate decreased with increasing irrigation (or precipitation), whereas the amount of N leached increased with irrigation. Evapotranspiration from a catch cropped soil was close to the potential evapotranspiration under optimal growth conditions.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121719558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crop production in relation to cultural practices in the Chromolaena odorata fallow system in South-West Côte d'Ivoire.","authors":"J.J.P. Slaats, B. Janssen, M. Wessel","doi":"10.18174/NJAS.V46I3.485","DOIUrl":"https://doi.org/10.18174/NJAS.V46I3.485","url":null,"abstract":"Farmers grow food crops alternated by short fallow periods of the naturally re-establishing Chromolaena odorata in response to the growing demand for land in humid Africa. It is unknown whether current cultural practices in this system are appropriate and how land use can further be intensified. Maize production was measured in experiments on three sites cleared from a two-, three- and four-year-old C. odorata fallow, respectively. On the two-year-old site, bearing the lowest quantity of vegetation biomass, maize response to removing, burning and intensively burning (i.e.: burning after adding vegetation from outside) the slashed vegetation was studied as well. Various weeding frequencies and fertilizers were applied in the experiments to better assess the effects of the length of the fallow period and the clearing methods. The experiments were conducted during three consecutive cropping seasons to provide an indication of changes in yield over time. During the first season after clearing, maize yield decreased from 3.8 on the four-year-old fallow to 2.6 t ha-1 on the two-year-old fallow. This reduction was due to a lower availability of P and N, and to a higher competition from weeds. Burning or intensively burning the vegetation raised yields of the unfertilized crop, up to 1.2 t ha-1. It increased the availability of phosphorus but did not clearly reduce competition from weeds. In the second and third season, yield fell to 1.5 t ha-1 irrespective of the fallow age. Burning slowed down the yield decline over time. Application of P- and N-fertilizers raised crop yields under all conditions and maintained them up to 5 t ha-1 during the three seasons. Weeding twice instead of once reduced the yield decline over time on the young fallow only. Results suggest that in the C. odorata crop production system a fallow period of two years is too short to be fully effective, that burning the C. odorata slash benefits crop production, even when its amount is limited, and that growing maize for more than one season is worthwhile only where fertilizers are applied.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133158421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the dry weight rank method for botanical analysis of grassland by means of simulation","authors":"J. Neuteboom, E. Lantinga, P. Struik","doi":"10.18174/NJAS.V46I3.484","DOIUrl":"https://doi.org/10.18174/NJAS.V46I3.484","url":null,"abstract":"With the Dry Weight Rank (DWR) method of 't Mannetje and Haydock [see Journal of British Grassland Society (1963) 18, 268-275] for botanical analysis in pastures, the dry weight proportions of species are estimated from their first, second and third ranks in dry weight in single quadrats. The yield correction of Haydock and Shaw [see Australian Journal of Experimental Agriculture and Animal Husbandry (1975) 15, 663-670] is used additionally to solve the problem of the respective under- and overestimates of the dry weight proportions of high and low yielding species when these grow in patches. In this paper the DWR method is evaluated by means of computer simulation. Main element of the simulation model is a computer sampling program with which a fictitious vegetation can be sampled with a circular quadrat. The output shows that the DWR method works well using relatively small sampling quadrats with, on average, only a few plants per quadrat, irrespective of the horizontal vegetation structure. In vegetations where species grow patchwise, satisfactory results are also obtained using large quadrats with much more plants (i.e. tens) per quadrat. The reason is that in these cases also minor species can compete successfully for first, second and third ranks. However, it appeared that only a certain degree of patchiness is necessary, and with the usually applied quadrat sizes up to 25 dmsuperscript 2, probably in most vegetations this condition is fulfilled. Care should be taken in applying the DWR method for estimating species composition in recently sown grasslands where species usually occur more or less at random. In those cases, in principle a very small sampling quadrat (smaller than 1 dmsuperscript 2) could be used. However, this has practical limitations since the quadrat size should not be too small for realistic yield estimations, needed for the Haydock & Shaw yield correction. The simulations revealed that one condition (i.e., that the sampling quadrat should be at least as large that it usually contains three or more species) is not necessary because of the almost always perfect functioning of the correction for missing ranks. Generally speaking, a sampling quadrat should be chosen not larger than is strictly necessary from the viewpoint of horizontal vegetation structure and from the viewpoint of realistic yield estimations. Multipliers calculated from simulation data could satisfactorily mimic the original multipliers of DWR given by 't Mannetje & Haydock. It is postulated that the DWR method is well suited for studying vegetation changes in old, floristically diverse grasslands with dominant species often in moderate dry weight proportions and species usually growing in patches.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134634845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leaf CO2 assimilation and leaf dynamics in catch crops during autumn and winter at two levels of nitrogen supply","authors":"A. V. Dam, E. Lantinga","doi":"10.18174/njas.v46i3.482","DOIUrl":"https://doi.org/10.18174/njas.v46i3.482","url":null,"abstract":"This study relates the leaf CO2 assimilation and leaf dynamics of nitrogen catch crops to environmental conditions. Winter rye (Secale cereale) and fodder radish (Raphanus sativus) were grown as catch crops in an outdoor pot experiment at two rates of nitrogen supply (N2 higher than N1) in Wageningen, Netherlands, from August 1993 until April 1994. Biomass increased with increasing N supply. There was no net growth after mid-November. The number of tillers in rye and of appeared leaves in radish were higher in N2 than in N1. Leaf appearance rate increased with temperature in fodder radish and rye. Tillering in rye ceased in mid-October. Leaf lifespan was related to the temperature sum between leaf emergence and leaf death. Leaf lifespan was 478 +or- 68 degrees C day in fodder radish. In rye, the leaf lifespan gradually decreased from 592 +or- 66 to 389 +or- 25 degrees C day and from 545 (1 observation) to 401 +or- 64 degrees C day in N1 and N2, respectively. In young leaves, Amax (light-saturated CO2 assimilation rate) was approximately 1.2 mg CO2 m-2 leaf s-1 in September and 0.5 mg CO2 m-2 leaf s-1 later on, independent of species and N supply, N supply affected the organic N concentrations only in the older leaves. Amax was not dependent on temperature at measurement (range: 12-19 degrees C in September, 5-15 degrees C from November until March), but, in contrast, strongly related to temperature and irradiance during the preceding growth period. Leaf nitrate concentrations increased with N supply. Water-soluble carbohydrate concentrations were higher in N1 than in N2 and higher in rye than in fodder radish. They fluctuated during the season. It is concluded that overall growth rates were limited by process rates other than that of leaf CO2 assimilation per unit leaf area in both N1 and N2.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116460657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heavy-metal balances of agro-ecosystems in the Netherlands","authors":"S. Moolenaar, T. Lexmond","doi":"10.18174/njas.v46i2.489","DOIUrl":"https://doi.org/10.18174/njas.v46i2.489","url":null,"abstract":"Heavy-metal flows (Cd, Cu, Pb, and Zn) of arable, dairy and mixed farming systems in the Netherlands were studied, and farm-gate and field-scale balances calculated. On the field-scale, static and dynamic balances were distinguished. By determining the characteristic metal flows, it became possible to differentiate between farming systems and to select the most viable options for sustainable heavy-metal management. Crop rotation, and choice of fertilizers, clearly influenced the heavy-metal balance of arable farming systems. In dairy farming systems, the role of feed management was very important, but the effects on the heavy-metal balance were not always straightforward. Mixed farming systems compared favourably with specialized (arable or dairy) farming systems with regard to heavy-metal accumulation. Due to the internal cycling of feedstuff and manure, lower inputs were required and therefore the import of heavy-metal containing raw materials and products was minimized. Uncertainties related to the calculation of heavy-metal balances are discussed.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126709440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrogen recovery and dry matter production of silage maize (Zea mays L.) as affected by subsurface band application of mineral nitrogen fertilizer","authors":"W. Dijk, G. Brouwer","doi":"10.18174/NJAS.V46I2.487","DOIUrl":"https://doi.org/10.18174/NJAS.V46I2.487","url":null,"abstract":"In 1991-94 the effects of subsurface band application of mineral N fertilizer on the N recovery and dry matter (DM) yield of silage maize were studied in nine field experiments on sandy and clay soils in the Netherlands. In the early crop stages and especially in the clay soil experiments, banded N had a significant negative effect on the N uptake and DM yield compared to broadcast N, possibly due to salt damage. At final harvest, however, banding significantly increased the N uptake and DM yield in most of the experiments. The apparent N recovery increased by circa 20-25% (absolute). The positive effects indicated that band application improved the efficiency of the N fertilizer. It could be calculated that banding allowed a reduction in the N rate of 20-30% without significant effects on the N uptake and DM yield of the silage maize. Benefits of banding were positively (P<0.001) related to the accumulated precipitation in the whole growing season. When N was broadcast, soil mineral N measurements showed that, initially, N was preferably taken up from soil compartments near the maize row resulting in lateral gradients, that sometimes even persisted until final harvest. Band application resulted in strong lateral gradients in the early crop stages, decreasing during the growing season due to N uptake by the maize crop. Root counting in two experiments showed that banding also seemed to affect root proliferation. Effects were, however, not consistent. Relatively more roots were found near the banded N in 1991 while in 1992 roots tended to avoid soil compartments with high N concentrations.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127874878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}