Biology Faculty Research, Publications and Presentations
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Corkett, Christopher (March 26, 2012)[more][less]
Abstract: It has not always been realised that Karl Popper's demarcation criterion, the criterion he uses to distinguish an empirical science from its 'metaphysical' complement involves an interpretation of the classical theory of terms. From the beginning Popper's criterion never was an attempt to distinguish some subject matter called 'science' from some subject matter called 'metaphysics'. His criterion of falsifiability always was an attempt to distinguish the logical strength of a universal law from the logical weakness of its complement, a complement that can bear no fruit. For example: if the falsifiability criterion is applied to the management of the fisheries of Atlantic Canada we can distinguish the bold and sound management of Atlantic lobster from the weak and unsound management of Atlantic groundfish. In the early 1990's Newfoundland's fishery for Atlantic cod suffered a major collapse that has become one of the world's most prominent case studies of failure in fisheries management. Under Popper's analytic theory of demarcation a weak management with no problem solving potentiality is to be held responsible for the collape of Newfoundland's Atlantic cod fishery. Description: Christopher is currently applying Karl Popper's non-inductive theory of method to the management of the world's commercial fisheries. URI: http://hdl.handle.net/10222/14525 Files in this item: 1
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Patriquin, D.G.; Burton, D. (Borkhauser Verlag: Basel, Boston, Stuttgart., January 1, 1982)[more][less]
Abstract: For farmers in Nova Scotia who wish to be self-sufficient in animal feed, and in N fertilizer, the faba bean offers a number of advantages over soybean: (i) no special processing is required; (ii) nodulation is generally spontaneous in N.S. soils (no inoculation required); (iii) nitrogen fixation is roughly double that of soybean; (iv) faba bean is better adapted than soybean for growth on low nitrate soils. Nitrogen fixation (ca 140 kg N/ha) is sufficient to allow the N balance in a rotation system to be maintained or augmented when manures are returned to the field. The main problem is to ensure that the N from animal and green manures is available to plants when required. This problem must be approached at the local level. In addition, selection of suitable varieties and appropriate rnanagement strategies are essential in combatting Chocolate Spot, its major disease. URI: http://hdl.handle.net/10222/14442 Files in this item: 1
FabaMontreal1982.pdf (2.586Mb) -
Patriquin, D.G. (COGnition (Eco-Farm & Garden), NaN, 1988)[more][less]
Abstract: A popular account of scientific research on the processes involved in the transition of a mixed laying hen-grain farm In the Annapolis Valley, Nova Scotia from conventional to organic management. URI: http://hdl.handle.net/10222/14441 Files in this item: 1
PatriquinTunwathCOG.pdf (2.400Mb) -
Patriquin, D.G.; Burton, D.; Hill, N. (Plenum Publishing Corporation, NaN, 1981)[more][less]
Abstract: To what extent can a mixed farm be self sufficient in nitrogen by growing nitrogen-fixing legumes and recycling animal manures? An opportunity to examine this question was provided by an upland farm in the Annapolis Valley of Nova Scotia where faba beans (Vicia faba L. minor) were grown on 1/3rd of the cultivated land, grains from cereals and faba bean were fed to laying hens and the manure was applied to cereals. The farmer had ceased to apply commercial fertilizers and herbicides after 1975, thinking that inputs of N (nitrogen) via legume nitrogen fixation should be sufficient, and that weeds could be adequately controlled by mechanical means. His cereal yields fell abruptly, apparently because of insufficient N. Was the apparent N deficiency due to low nitrogen fixation in faba beans and/or to high losses via leaching, export of N from the farm in eggs, ammonia volatilization, denitrification and/or to excessive weeds? To address this question, in 1978-79 we examined patterns of faba bean root+nodule nitrogenase activity, leaf nitrate reductase activity and N accumulation and removals in faba bean on this upland farm and on a nearby dykeland farm. The total N input via N2 fixation was estimated by applying a reported ratio of acetylene reduction to N2 fixation, and by comparison of N accumulation in faba bean with that in non-legume plots. Observations on crop and weed biomass and N content, manure N, soil nitrate and ammonia volatilized after application of manure to microplots were conducted on the upland farm; denitrification in soil cores on the dykeland farm was estimated using the acetylene blockage technique. The composition, seed banks and biomass of weeds on these farms and two other farms and their response to added fertilizer-N were also examined. The observations indicate that atmospheric N2 and soil-N were the major sources of N for faba beans during vegetative and reproductive growth successively. For both farms, N removed in faba bean seeds exceeded N fixation, indicating a negative soil N balance for the faba beans. However, for the upland farm (where the a large portion of the seed-N is recycled via hen manure), a nitrogen budget indicated a large excess of inputs of N via nitrogen fixation over losses of N and suggested that the excess N was accumulating in the soil organic matter (SOM). In essence, SOM (approx. 5% N by weight) was increasing at the expense of increased crop production. It could be expected that as SOM accumulates over time, the amount of N available to crops via soil N mineralization will increase. Rough calculations indicated that once a steady state is reached, the N mineralized from SOM would be sufficient to support yields equivalent to or better than those attained when commercial fertilizers were used. but also that it would take of the order of 100 years for yields to approach desired levels. Thus a strategy for increasing yields of "wait and let the organic matter accumulate" is not practical. It was concluded that a faster increase in yields could be achieved by "restructuring" the farm system so that more of the N circulates through the crops and less through weeds and soil organic matter. To this end, a regular crop rotation was implemented in 1980: faba beans - oats - clover - winter wheat. The clover is seeded with oats in year 2, and is turned under in year 3 prior to planting winter wheat. Manure is applied to the oats and wheat. Maintenance of nearly continuous plant cover is a key consideration. Thus it is desired to control annual weeds during the crop season, but not to eliminate them so that they provide a self-seeding cover when crops are not present. URI: http://hdl.handle.net/10222/14440 Files in this item: 1
PatriquinStrategies1981.pdf (7.660Mb) -
Patriquin, D.; Hubbard, S.; Scott, J. (REAP-Cumberland, Shinimicas, Nova Scotia, June 1, 1993)[more][less]
Abstract: Existing livestock systems in Cumberland Co. rely mainly on grass, clover and spring cereals for home grown forage and grain. There are well known limitations to these systems on the fragipan or basil till soils which predominate in the county and which often suffer from early season wetness and mid-summer drought. Together with the high costs of fertilizers or of purchased feed in comparison to farm gate prices, these limitations contribute to the poor economic status of many of the farms in the county. This two year project evaluated a number of low input/sustainable practices for their applicability to livestock farms in Cumberland County. The practices were ones that had been researched initially elsewhere, but either have not been widely adopted by farmers or had not been tested locally. They were identified by REAP-Cumberland farmers in consultation with researchers as ones that could help overcome specific limitations to feed production, reduce input costs and protect the environment. Five sets of experiments or trials were set up in 1990 on one or more of four livestock farms (sheep and beef/sheep/dairy/hogs and beef). The first four experiments were examined in relation to a model rotation, which was developed through discussion between the researchers and farmers: Year 1 GRAIN LEGUME/HAY; Year 2 HAY; Year 3 HAY; Year 4 HAY/WINTER CEREAL, Year 5: WINTER CEREAL/CATCH CROP. The five sets of experiments examined (1) use of grain legumes (fababeans and lupins) for silage and as nurse crops, (2) improvement of hay quality by fertilization and by use of improved mixes, (3) strip trials of winter cereals (triticale, rye, wheat and mixtures of the same), (4) use of catch crops after winter cereals, (5) ryegrass/legume, and winter cereal/legume mixtures as lower cost alternatives to ryegrass for summer pasture. Lupins and fababeans yielded well, made acceptable silage, and allowed good establishment of undersown triple mix. The data from the hay mix experiments indicate that hay productivity can be improved at sites not receiving high N loadings by use of improved mixes containing alternatives to Alsike clover; that more complex mixes on average will perform most predictably, and that a medium or higher level of soil calcium is necessary to realize the full potential of the improved mixes. In strip trials of winter cereals on two farms, the rye-wheat mixture gave the best yields. In the catch crop experiments, the best cover achieved by late fall was 80%, which was by oil radish; it accumulated 20-30 kg N above that in weeds in control plots. It is suggested that better cover and conservation of N might be achieved by sowing cover crops into cereals in spring. In trials of alternatives to ryegrass for summer pasture, winter cereals did not yield well compared to ryegrass; nitrate in ryegrass reached levels of 1-3% at the two more heavily fertilized sites, which is in the potentially toxic range. In addition, a variety of informal research was conducted during the course of the project. Trials of different rye varieties and of spelt, fertilized with only manure, were conducted at two farms over two years. Schmidt rye, which had been selected on an organic farm in Ontario, produced high grain yield and an exceptionally high straw yield; the straw component is of particular value on these livestock farms; Spelt (potential cash crop for the organic market) also yielded well, and with the Schmidt rye, was multiplied on larger acreages. A system for managing residues and controlling weeds in organic vegetable production was tested. It involves incorporation of residues in the fall in raised beds, and growing winterkilled cover crops. It provided excellent control of weeds in the following year with no cultivation. URI: http://hdl.handle.net/10222/14432 Files in this item: 1
CumberlandLivestockFarms.pdf (52.75Mb)