This study evaluated the persistence of atrazine in the soil and movement in surface runoff and shallow phreatic flow. Atrazine persisted in the surface 10 cm of soil for over 4 months. However, it could not be detected at greater depths after approximately 2 months. Persistence (time) in the soil did not vary significantly with application rate. Initial concentrations in the soil did, however, vary significantly. Initial atrazine concentrations in the soil for the 4.48 kg ha−1 application rate were approximately twice those at the 2.24 kg ha−1 rate. Atrazine was not detected in significant amounts in surface runoff after 26 days and was not observed at any time in the subsurface flow from the treated area. Total losses for the 2 rates in 1974 and 1975 ranged from 0.22–2.24%. Concentrations in the soil and surface runoff were directly related to application rates.
本研究评估了阿特拉津在土壤中的持久性以及在地表径流和浅层潜水流中的运动。阿特拉津在10厘米土壤表层持续存在4个月以上。然而,大约2个月后,在更深的深度无法检测到它。土壤滞留时间随施用量变化不显著。然而,土壤中的初始浓度确实变化很大。施用4.48 kg ha - 1时,土壤中阿特拉津的初始浓度约为施用2.24 kg ha - 1时的两倍。26天后,没有在地表径流中检测到大量的阿特拉津,也没有在任何时候从处理区域流出的地下水流中观察到阿特拉津。1974年和1975年两种费率的总损失为0.22-2.24%。土壤和地表径流中的浓度与施肥量直接相关。
{"title":"Atrazine persistence in soil and transport in surface and subsurface runoff from plots in the coastal plain of the southern united states","authors":"W.A. Rohde, L.E. Asmussen, E.W. Hauser, M.L. Hester, H.D. Allison","doi":"10.1016/0304-3746(81)90004-4","DOIUrl":"10.1016/0304-3746(81)90004-4","url":null,"abstract":"<div><p>This study evaluated the persistence of atrazine in the soil and movement in surface runoff and shallow phreatic flow. Atrazine persisted in the surface 10 cm of soil for over 4 months. However, it could not be detected at greater depths after approximately 2 months. Persistence (time) in the soil did not vary significantly with application rate. Initial concentrations in the soil did, however, vary significantly. Initial atrazine concentrations in the soil for the 4.48 kg ha<sup>−1</sup> application rate were approximately twice those at the 2.24 kg ha<sup>−1</sup> rate. Atrazine was not detected in significant amounts in surface runoff after 26 days and was not observed at any time in the subsurface flow from the treated area. Total losses for the 2 rates in 1974 and 1975 ranged from 0.22–2.24%. Concentrations in the soil and surface runoff were directly related to application rates.</p></div>","PeriodicalId":100066,"journal":{"name":"Agro-Ecosystems","volume":"7 3","pages":"Pages 225-238"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-3746(81)90004-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84479853","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}
Pub Date : 1981-08-01DOI: 10.1016/0304-3746(81)90026-3
J. Karlovsky
This paper is concerned with reinterpretation of published data on efficiency of nutrient utilisation in agro-ecosystems. A close examination of nutrient cycles both under pastoral and arable farming in various countries shows conclusively that the utilisation of phosphorus and potassium in the majority of ecosystems is very high, more than 70% of the added and recycled and K being either utilised by plants or remaining in a chemical form available to plants. This conclusion is in conflict with the traditional belief that due to the process of large-scale P fixation the major part of the added P is fixed in the soil in compounds not available to plants.
{"title":"Cycling of nutrients and their utilisation by plants in agricultural ecosystems","authors":"J. Karlovsky","doi":"10.1016/0304-3746(81)90026-3","DOIUrl":"10.1016/0304-3746(81)90026-3","url":null,"abstract":"<div><p>This paper is concerned with reinterpretation of published data on efficiency of nutrient utilisation in agro-ecosystems. A close examination of nutrient cycles both under pastoral and arable farming in various countries shows conclusively that the utilisation of phosphorus and potassium in the majority of ecosystems is very high, more than 70% of the added and recycled and K being either utilised by plants or remaining in a chemical form available to plants. This conclusion is in conflict with the traditional belief that due to the process of large-scale P fixation the major part of the added P is fixed in the soil in compounds not available to plants.</p></div>","PeriodicalId":100066,"journal":{"name":"Agro-Ecosystems","volume":"7 2","pages":"Pages 127-144"},"PeriodicalIF":0.0,"publicationDate":"1981-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-3746(81)90026-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78321458","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}
Pub Date : 1981-08-01DOI: 10.1016/0304-3746(81)90024-X
E. Dayan , H. Van Keulen , A. Dovrat
The dynamics in tiller population and dry-matter accumulation of a grass sward, cut at different time intervals, was compared with a descriptive simulation model. The model was validated against experimental data of tiller number, and dry-matter accumulation for irrigated cv. Katambora Rhodes grass (Chloris gayana Kunth), cut at intervals of 1, 2, 3 or 4 weeks. The model predicted that the initial rate of regrowth following long cutting intervals was much slower than the regrowth following short cutting intervals. The simulations also showed that relatively high dry-matter yields alternated with relatively low dry-matter yields when the interval between cuttings was long. These results were in reasonable agreement with the measured values. The fluctuation in the number of tillers and dry-matter yield was attributed mainly to the formation of culmed-vegetative tillers, common to Rhodes grass at an early stage of development, which renders them incapable of regrowth after defoliation.
{"title":"Tiller dynamics and growth of Rhodes grass after defoliation: A model named TILDYN","authors":"E. Dayan , H. Van Keulen , A. Dovrat","doi":"10.1016/0304-3746(81)90024-X","DOIUrl":"10.1016/0304-3746(81)90024-X","url":null,"abstract":"<div><p>The dynamics in tiller population and dry-matter accumulation of a grass sward, cut at different time intervals, was compared with a descriptive simulation model. The model was validated against experimental data of tiller number, and dry-matter accumulation for irrigated cv. Katambora Rhodes grass (<em>Chloris gayana</em> Kunth), cut at intervals of 1, 2, 3 or 4 weeks. The model predicted that the initial rate of regrowth following long cutting intervals was much slower than the regrowth following short cutting intervals. The simulations also showed that relatively high dry-matter yields alternated with relatively low dry-matter yields when the interval between cuttings was long. These results were in reasonable agreement with the measured values. The fluctuation in the number of tillers and dry-matter yield was attributed mainly to the formation of culmed-vegetative tillers, common to Rhodes grass at an early stage of development, which renders them incapable of regrowth after defoliation.</p></div>","PeriodicalId":100066,"journal":{"name":"Agro-Ecosystems","volume":"7 2","pages":"Pages 101-112"},"PeriodicalIF":0.0,"publicationDate":"1981-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-3746(81)90024-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76487886","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}
Pub Date : 1981-08-01DOI: 10.1016/0304-3746(81)90025-1
E. Dayan , H. van Keulen , A. Dovrat
The crop growth simulation model BACROS describing production under optimum conditions of water and nutrient supply, is tested with data collected in field experiments with Rhodes grass (Chloris gayana Kunth). The choice of specific parameters for the plant species is discussed and special attention is paid to stomatal behaviour. It was concluded that in all situations examined (climate room, greenhouse and field), stomatal aperture was determined by the CO2 concentration inside the stomatal cavity and hence by the rate of assimilation. Measured and calculated rates of assimilation, respiration and transpiration of an artificial sward showed good agreement. In the field situation the maximum rate of dry matter accumulation was predicted with reasonable accuracy as was the rate of water use. Initial growth rates and the rate of growth towards the end of the growing period showed deviations. The former inaccuracies were associated with the death of tillers, the latter with the formation of flowering stems.
{"title":"Experimental evaluation of a crop growth simulation model. A case study with rhodes grass","authors":"E. Dayan , H. van Keulen , A. Dovrat","doi":"10.1016/0304-3746(81)90025-1","DOIUrl":"10.1016/0304-3746(81)90025-1","url":null,"abstract":"<div><p>The crop growth simulation model BACROS describing production under optimum conditions of water and nutrient supply, is tested with data collected in field experiments with Rhodes grass (<em>Chloris gayana</em> Kunth). The choice of specific parameters for the plant species is discussed and special attention is paid to stomatal behaviour. It was concluded that in all situations examined (climate room, greenhouse and field), stomatal aperture was determined by the CO<sub>2</sub> concentration inside the stomatal cavity and hence by the rate of assimilation. Measured and calculated rates of assimilation, respiration and transpiration of an artificial sward showed good agreement. In the field situation the maximum rate of dry matter accumulation was predicted with reasonable accuracy as was the rate of water use. Initial growth rates and the rate of growth towards the end of the growing period showed deviations. The former inaccuracies were associated with the death of tillers, the latter with the formation of flowering stems.</p></div>","PeriodicalId":100066,"journal":{"name":"Agro-Ecosystems","volume":"7 2","pages":"Pages 113-126"},"PeriodicalIF":0.0,"publicationDate":"1981-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-3746(81)90025-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76357118","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}
Pub Date : 1981-08-01DOI: 10.1016/0304-3746(81)90027-5
Richard N. Mack
Bromus tectorum L., the most ubiquitous alien in steppe vegetation in the intermountain West of North America, entered British Columbia, Washington, and Utah ca. 1889–1894. By ca. 1928 the grass had reached its present distribution occupying much of the perennial grasslands in Washington, Idaho, Oregon, Nevada, Utah and British Columbia as native grasses dwindled with overgrazing and cultivation. In the process this cleistogamous winter annual may have competitively displaced both native colonizers (including cleistogamous us annual grasses) as well as the dominants of climax stands. The spread of B. tectorum demonstrates the degree of success an alien may achieve when preadaption, habitat alteration simultaneous with entry, unwitting conformation of agricultural practices to the plant's ecology and apparent susceptibility of the native flora to invasion, are all in phase.
{"title":"Invasion of Bromus tectorum L. into Western North America: An ecological chronicle","authors":"Richard N. Mack","doi":"10.1016/0304-3746(81)90027-5","DOIUrl":"10.1016/0304-3746(81)90027-5","url":null,"abstract":"<div><p><em>Bromus tectorum</em> L., the most ubiquitous alien in steppe vegetation in the intermountain West of North America, entered British Columbia, Washington, and Utah ca. 1889–1894. By ca. 1928 the grass had reached its present distribution occupying much of the perennial grasslands in Washington, Idaho, Oregon, Nevada, Utah and British Columbia as native grasses dwindled with overgrazing and cultivation. In the process this cleistogamous winter annual may have competitively displaced both native colonizers (including cleistogamous us annual grasses) as well as the dominants of climax stands. The spread of <em>B. tectorum</em> demonstrates the degree of success an alien may achieve when preadaption, habitat alteration simultaneous with entry, unwitting conformation of agricultural practices to the plant's ecology and apparent susceptibility of the native flora to invasion, are all in phase.</p></div>","PeriodicalId":100066,"journal":{"name":"Agro-Ecosystems","volume":"7 2","pages":"Pages 145-165"},"PeriodicalIF":0.0,"publicationDate":"1981-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-3746(81)90027-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73316880","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}
Pub Date : 1981-06-01DOI: 10.1016/0304-3746(81)90019-6
E.G. Mahn
{"title":"Verhandlungen Gesellschaft für ökologie, band VII","authors":"E.G. Mahn","doi":"10.1016/0304-3746(81)90019-6","DOIUrl":"10.1016/0304-3746(81)90019-6","url":null,"abstract":"","PeriodicalId":100066,"journal":{"name":"Agro-Ecosystems","volume":"7 1","pages":"Pages 88-89"},"PeriodicalIF":0.0,"publicationDate":"1981-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-3746(81)90019-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78267433","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}