Netherlands Journal of Agricultural Science最新文献_第9页

Effect of fibrous and starchy carbohydrates in concentrates as supplements in a herbage-based diet for high-yielding dairy cows. 高产奶量奶牛草料基础饲粮中添加纤维性和淀粉性碳水化合物的效果。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/NJAS.V38I3B.16572

H. Valk, H. W. K. Poelhuis, H. Wentink

引用次数: 56

Ruminal availability of nitrogen and carbohydrates from fresh and preserved herbage in dairy cows. 奶牛新鲜和腌制牧草氮和碳水化合物的瘤胃利用率。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/NJAS.V38I3B.16574

A. M. Vuuren, S. Tamminga, R. Ketelaar

引用次数: 73

A simple model of P uptake by crops as a possible basis for P fertilizer recommendations. 作物吸收磷素的简单模型可作为磷肥推荐的可能依据。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/NJAS.V38I3A.16591

M. Noordwijk, P. Willigen, P. Ehlert

{"title":"A simple model of P uptake by crops as a possible basis for P fertilizer recommendations.","authors":"M. Noordwijk, P. Willigen, P. Ehlert","doi":"10.18174/NJAS.V38I3A.16591","DOIUrl":"https://doi.org/10.18174/NJAS.V38I3A.16591","url":null,"abstract":"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)","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134418352","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}

引用次数: 67

Amino acid requirements of pigs. 3. Requirement for apparent digestible threonine of pigs in different stages of growth. 猪的氨基酸需要量。3.。不同生长阶段猪对表观可消化苏氨酸的需要量。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/NJAS.V38I3B.16582

N. Lenis, J. V. Diepen

{"title":"Amino acid requirements of pigs. 3. Requirement for apparent digestible threonine of pigs in different stages of growth.","authors":"N. Lenis, J. V. Diepen","doi":"10.18174/NJAS.V38I3B.16582","DOIUrl":"https://doi.org/10.18174/NJAS.V38I3B.16582","url":null,"abstract":"The requirement for threonine of pigs was examined in feeding experiments on individually housed pigs in the live weight range 45 to 105 kg and on group-housed pigs in the live weight range 65 to 95 kg. Lysine supply corresponded with the lysine requirement of growing-finishing pigs. To a negative control diet, containing 134 g kg* 1 crude protein and 4.5 g kg- 1 threonine, three levels of supplements of L-threonine (0.6, 1.2 and 1.8 g kg -1 ) were tested. These results were compared with those of a positive control diet containing 152 g kgcrude protein and 5.7 g kg -1 threonine. To prevent other amino acids than threonine to be limiting, the negative control diet was supplemented with lysine, methionine, trypto phan, isoleucine, histidine and valine. The positive control diet was only supplemented with lysine and methionine. The requirement for total threonine of growing-finishing pigs for maximum growth performance was found to be approximately 5.6 g kg-' in a diet contain ing 9.4 MJ NE f kg -1 . This figure corresponds with approximately 4.7 g kg~' apparent fae cal digestible threonine and 4.3 g kg-' apparent ileal digestible threonine. There was no sig nificant difference in response between the growing and the finishing pigs. The requirement for ileal digestible threonine, relative to ileal digestible lysine requirement, was approximately 64 %. It appeared, that dietary protein levels can be reduced with 2 percentage units without any disadvantageous effect on growth performance, when limiting amino acids are sup plemented sufficiently.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123832985","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}

引用次数: 8

Modelling organic matter dynamics in different soils. 模拟不同土壤中的有机质动态。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/njas.v38i3a.16585

E. Verberne, J. Hassink, P. Willigen, J. Groot, J. V. Veen

引用次数: 249

Chemical composition of animal manure: a modelling approach. 动物粪便的化学成分:一种建模方法。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/njas.v38i3a.16592

J. Bril, W. Salomons

引用次数: 65

Heavy metals and organic micropollutants in floodplains of the river Waal, a distributary of the river Rhine, 1958-1981. 1958-1981年莱茵河支流瓦尔河漫滩的重金属和有机微污染物。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/njas.v38i3a.16595

J. Japenga, K. H. Zschuppe, A. D. Groot, W. Salomons

{"title":"Heavy metals and organic micropollutants in floodplains of the river Waal, a distributary of the river Rhine, 1958-1981.","authors":"J. Japenga, K. H. Zschuppe, A. D. Groot, W. Salomons","doi":"10.18174/njas.v38i3a.16595","DOIUrl":"https://doi.org/10.18174/njas.v38i3a.16595","url":null,"abstract":"During periods of high water discharge, dyke-protected floodplains of the river Rhine in the Netherlands become inundated and suspended matter from the river settles out. In the last 30 years, floodplain top layers have been sampled several times just after deposition; samples were dried and stored in a specimen bank. The samples were used to assess the development of sediment contamination with heavy metals and organic micropollutants during the past decades. Heavy metals studied include Zn, Cu, Cr, Pb, Cd, Ni, Hg and As. Different groups of chemically persistent organic micropollutants were studied: polycyclic aromatic hydrocarbons, polychlorobiphenyls, hexachlorobenzene, DDT and DDT-metabolites. The levels of most contaminants decreased substantially between 1958 and 1981. The variation among the different floodplain locations is due to differences in hydrodynamic characteristics of the location. A comparison was made between the concentrations found and the levels considered acceptable if the floodplain area is used for cattle grazing; a comparison was also made with estimated natural background levels and with reference values defined by the Dutch government. (Abstract retrieved from CAB Abstracts by CABI’s permission)","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116091429","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}

引用次数: 27

Comparison of multivariate calibration methods for prediction of feeding value by near infrared reflectance spectroscopy. 近红外反射光谱预测进料值的多变量标定方法比较。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/NJAS.V38I3B.16570

P. Goedhart

引用次数: 17

Structural and non-structural carbohydrates in concentrate supplements of silage based dairy cow rations. 青贮型奶牛口粮精料补充中的结构性和非结构性碳水化合物。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/NJAS.V38I3B.16573

H. D. Visser, P. V. D. Togt, S. Tamminga

引用次数: 60

Comparison of the content of clostridial spores in wilted grass silage ensiled in either laboratory, pilot-scale or farm silos. 枯草青贮在实验室、中试和农场筒仓中梭状芽孢杆菌孢子含量的比较。

Netherlands Journal of Agricultural Science Pub Date : 1990-09-01 DOI: 10.18174/NJAS.V38I3B.16568

S. Spoelstra

{"title":"Comparison of the content of clostridial spores in wilted grass silage ensiled in either laboratory, pilot-scale or farm silos.","authors":"S. Spoelstra","doi":"10.18174/NJAS.V38I3B.16568","DOIUrl":"https://doi.org/10.18174/NJAS.V38I3B.16568","url":null,"abstract":"Fifty-two laboratory silages (1.5 1), 108 samples of pilot-scale silos (2-4 tonnes), and 167 sam ples of farm silages were analysed for their contents of clostridial spores, proximate composi tion and concentrations of fermentation products. Numbers of clostridial spores in the silages ranged from 100 to more than 10 million per gram. Relationships between spore counts as dependant variable and dry matter, butyric acid and ammonia-N contents as independant variables were established for the three types of silages by regression analyses. Similarity ex isted in the relationships found for pilot-scale and farm silages, showing a gradual drop of spore counts with higher dry matter levels. Laboratory silages differed in showing either a pronounced clostridial fermentation with high levels of butyric acid, ammonium-N and spores or showing no clostridial fermentation at all. In contrast to the larger-scale silages, no clostridial fermentation was found at dry matter contents above 250 g kg - 1 . 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 can not be used to predict spore counts in farm silages. The differences between the larger scale silages and laboratory silages are at tributed to the heterogeneity of the pilot-scale and farm silages. in silages. Butyric acid and ammonium contents, being products of clostridial activi ty,","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121580728","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}

引用次数: 27