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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Design and evaluation of liquid swine manure injectors for potato nutrient placement

Campbell, Allan J. January 1998 (has links)
A project was developed to determine the feasibility of using liquid hog manure as a nutrient source (Nitrogen) for the potato crop. A survey of liquid hog manure storage facilities on Prince Edward Island (P.E.I.) provided a sampling technique and the range of nutrients found on hog farms. It was concluded from the data that there were large differences between farms and on farm manure sampling was required to determine accurate nutrient applications. An infrastructure was designed, constructed and tested for storage, handling and the application of liquid hog manure at the Harrington Research Farm, Crops and Livestock Research Centre, Charlottetown, P.E.I. Data from the first of two three year experiments determined that the placement of liquid hog manure under the sown potato row and beside the row (0.23 m) provided yields better than manure placed between the sown rows. These yields were not different for the extra Nitrogen fertilizer treatment. The second field experiment examined the placement of liquid hog manure by various injector designs between the rows after the potato crop was planted. Potato tuber yield data over the three years indicated no differences among injector design nor between the injector treatments and the treatment which received the extra Nitrogen fertilizer. Over both experiments there was a decline in the severity of Rhizoctonia ( Rhizoctonia solani) in one year for plots receiving manure compared to those which received only inorganic fertilizer. There were no differences in the incidence or severity of scab (Streptomyces scabies) over the study. In general liquid manure can be used as nutrient source for the potato crop on P.E.I.
12

Evaluating the seasonal changes in calcium concentration and distribution in apple fruit after application of different calcium fertilisation strategies

Wilsdorf, Robert Ernst 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Localized calcium (Ca) deficiencies frequently develop independent from total Ca supply and total fruit Ca concentration. Bulk mineral analyses is therefore not completely suitable for determination of the susceptibility of fruit in developing Ca-linked fruit physiological disorders like bitter pit, as it supplies insufficient information regarding the spatial accumulation of Ca within the fruit. Additional Ca is applied either as soil or foliar applications, where soil applications are applied either after fruit set (pre-harvest) or in the period after harvest. The contribution of these different methods of Ca application to the total Ca concentration in "Braeburn" fruit was quantified over three consecutive growing seasons. Foliar applications have been proven to be successful in suppressing bitter pit development and improving the Ca status of the fruit. The effectiveness of different formulations of foliar Ca products in influencing these parameters was also determined. Furthermore, the distribution pattern of fruit Ca resulting from different application strategies was mapped using particle induced X-ray emission technology. In the "Braeburn" trial, mineral analyses indicated no significant differences between treatments in terms of Ca concentration at 80 days after full bloom (dafb). However, when soil applications occurred with active root growth (visually monitored), treatments differed significantly 80 dafb. Weekly foliar Ca applications from 28 dafb resulted in higher fruit Ca concentrations 80 dafb than a pre-harvest soil Ca application (January, 2010). A possible explanation for the inefficiency of pre-harvest soil Ca is the disintegration of xylem vessels from 40 dafb (before root uptake) for sensitive cultivars such as Braeburn. Bitter pit initiation has been shown to occur in the earlier part of the season. This, together with a reduced Ca supply to the fruit early in the season due to xylem disintegration (for sensitive cultivars), indicates the importance of early season foliar Ca applications. PIXE analyses were used to establish the radial Ca distribution in apples. Ca was concentrated in the skin and core, with very low values in the outer cortex. PIXE results indicated fruit Ca concentrations to be the lowest in the pre-harvest soil application treatment. This was in agreement with mineral analyses results. Ca enriched areas resulting from effective Ca delivery via the vascular bundles, had a profound effect on fruit Ca concentrations in the immediate core and cortex. At harvest, this effect was much more subtle and emphasizes the importance of untimely xylem rupturing on eventual fruit Ca concentration. At 80 dafb, treatments where foliar Ca was applied showed higher Ca concentrations in the outer cortex (where symptoms of bitter pit typically occur). Calflo™ fruit had significantly higher Ca concentrations in "Braeburn" compared to fruits from Foliar GS™ and GG™ treatments. Calflo™ and Calcimax™ had a higher active Ca percentage (12%) compared to Foliar GSTM and GGTM (10%). Adding the Lecithin™ (surfactant) to Calcimax™ is not recommended as it did not improve its uptake. In "Golden Delicious", the commercial spray program of seven, weekly foliar applications (Calcinit™) resulted in fruit with significantly higher Ca concentrations compared to other treatments. / AFRIKAANSE OPSOMMING: Kalsium (Ca) tekorte ontstaan gewoonlik in gelokaliseerde areas in die appelvrug en ontwikkel dikwels ten spyte van voldoende totale vrug Ca. Minerale analises van heel vrugte verskaf dus nie genoeg inligting aangaande die verspreiding van Ca in die vrug wanneer die ontwikkelling van fisiologiese defekte soos bitterpit ter sprake is nie. Addisionele Ca word gewoonlik aangewend as blaar- of grondtoedienings, waar grondtoedienings tipies voor-oes (net na set) of in die na-oes periode, toegedien word. Die bydraes van die verskillende toedieningsmetodes tot die totale Ca konsentrasie van "Braeburn" appels is geëvalueer oor drie agtereenvolgende seisoene. Blaartoedienings van Ca word algemeen gebruik om die voorkoms van bitterpit te beheer en die Ca konsentrasie van die vrug te verhoog. Die effektiwiteit van `n reeks blaartoedienings-produkte om hierdie faktore te verbeter, is ook ondersoek. Die spesifieke verspreiding van die Ca in die vrug is gekarteer na gelang van elke toediening deur middel van PIXE-analises (Particle induced X-ray emission). In die "Braeburn" proef was daar geen beduidende verskille in terme van vrug Ca konsentrasie op 80 dnvb (dae na volblom) nie. Daarteenoor, was daar wel beduidende verskille by 80 dnvb toe grond toedienings saam met aktiewe wortelgroei geskied het (visuele inspeksie). Weeklikse blaartoedienings vanaf 21 dnvb het gelei tot vrugte met betekenisvol hoër Ca konsentrasies as die behandeling waar grondtoedienings slegs voor-oes geskied het (Januarie 2010). `n Moontlike oorsaak vir die oneffektiwiteit van voor-oes grondtoedings is die vroeë disintigrasie van xileem vesels in die vrug (soms voor 40 dnvb en voor die aanvang van wortelopname) in sensitiewe kultivars soos "Braeburn". Hierdie vroeë inhibering van Ca voorsiening, tesame met die vroeë inisiasie van bitterpit, beklemtoon die belangrikheid van blaarbespuitings vroeg in die seisoen. Die PIXE-analises wat aangewend is om die radiale verspreiding van Ca in die vrug te bepaal het getoon dat Ca meestal in die skil en kern van die vrug gekonsentreer was, met baie lae konsentrasies in die buitenste korteks. Die laagste Ca konsentrasies is waargeneem in vrugte van die behandeling waar voor-oes Ca slegs as `n grondtoediening geskied het. Hierdie waarneming is in ooreenstemming met die mineraalanalise resultate. Ca verykte areas, afkomstig van die naby geleë vaatbundels (xileem vesels), het egter die grootste effek op vrug Ca konsentrasie gehad. Hierdie effek was nie so groot by oes nie en beklemtoon dus die belangrikheid van die funksionaliteit van die vaatbundels. Blaartoedienings kon die Ca konsentrasie in die buitenste korteks suksesvol verhoog - waar simptome van bitterpit tipies voorkom. Die Calflo™ behandeling het beduidende hoër Ca konsentrasies gehad as die Foliar GS™ en GG™ behandelings. Die Calflo™ en Calcimax™ behandelings het `n hoër aktiewe Ca persentasie (12%) relatief tot die Foliar GS™ en GG™ (10%) behandelings bevat. Die byvoeging van Lecithin™ by Calcimax™ word nie aanbeveel nie, omdat dit geensins Ca opname vermeerder het nie. In die "Golden Delicious" proef het die kommersiële behandeling (Sewe weeklikse spuite van Calcinit™) gelei tot vrugte met die hoogste Ca konsentrasie van al die behandelings.
13

Comportamento de milho (Zea Mays L.) e propriedades físicas do solo, no sistema plantio direto, em resposta a aplicação de fertilizante organomineral /

Santana, Cleverton Tiago Carneiro de, 1988- January 2012 (has links)
Orientador: Maria Helena Moraes / Banca: Sérgio Lázzaro de Lima / Banca: Sandro Roberto Brancalião / Resumo: Esta pesquisa foi conduzida com o objetivo de avaliar a resposta agronômica de Zea Mays L. à aplicação de fertilizante organomineral, aplicado via tratamento de sementes e foliar, também utilizando-se de metodologias para avaliação das raízes por meio de coleta e análise de imagens. Para tal, foi realizado um trabalho em área de plantio direto, em Latossolo Vermelho distroférrico, textura argilosa, na Fazenda Experimental Lageado da Faculdade de Ciências Agronômicas - Universidade Estadual Paulista, Município de Botucatu, SP (22º58'S e 48º23'W, 765 m de altitude média). O delineamento experimental utilizado foi o de blocos casualizados, com cinco repetições. Os tratamentos foram constituídos pela aplicação isolada ou em combinação de três biofertilizantes (Haf Plus, Haf Alfa e Haf Potassium) e por quatro épocas de aplicação (Tratamento de Semente, Estádio V3, Estádio V9 e Estádio V11). Cada parcela possuía 5,5 metros de comprimento por 3,6 m de largura. Foram feitas trincheiras para capturar imagens do sistema radicular pelo método do perfil. As imagens foram analisadas pelo software SAFIRA, resultando em área, comprimento e volume de raízes. Na mesma trincheira foram coletadas amostras de 10 cm3, com o auxílio de um cubo volumétrico, para determinar a massa de raízes secas. A aplicação de fertilizante organomineral provoca sinergismo para fósforo e antagonismo para boro e cobre. A melhor interação entre os produtos e épocas de aplicação é a utilização conjunta de Plus (TS) + Alfa (V9) + Potassium (V11), com efeito positivo nos componentes biométricos das plantas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This research was developed to evaluate the agronomic response of Zea mays L to the application of bio-fertilizer applied as seed and foliate treatment, evaluating the roots by collecting and analyzing images. To this end, work was undertaken in an area of no-tillage in Rhodic Eutrudox (or Red Latosol), clayey soils in three growing seasons, Faculty of Agricultural Sciences, State University of São Paulo (Universidade Estadual Paulista), Botucatu, SP (22 º 58'S and 48 º 23'W, 765 m average elevation). The trial design was made up of five (5) random trial blocks. The treatments were applied individually or in a combination of three bio-fertilizers (Haf Plus, Haf Alfa and Haf Potassium) and at four different stages (seed treatment, V3 Stadium, V9 Stadium and Stadium V11). Each plot was 5.5 meters long by 3.6 m wide. Trenches were dug to capture images of the root system via the profile method. The images were analyzed by the software SAFIRA, resulting in area, root length and volume. In the same trenches samples of 10 cm3 were collected with the aid of a volumetric cube to determine the dry root mass. The application of bio-fertilizer causes phosphorus synergism and boron and copper antagonism. A better interaction between the products and application times is the joint use of Plus (ST) + Alfa (V9) + Potassium (V11) with positive effect on biometric components of the corn plants. Treatment Plus (TS), at the time of application, is the biggest contributor to increasing biometric components and mass, length, volume and area of maize roots. Plus + Alpha applied to V11, either with or without Potassium, does not produce good results for average length of the spike, number of rows per ear, dry mass, area and volume of... (Complete abstract click electronic access below) / Mestre
14

Efffects of various fertiliser materials on growth, yield and nutritional quality of three tomato varieties

Mahlatji, Maphotle Baatseba January 2019 (has links)
Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2019 / Tomato (Solanum lycopersicum L.) is one of the most popular and widely consumed vegetable crops all over the world. They play a vital role in human diet and good sources of vitamins and minerals. However, low soil fertility is a major challenge to vegetable crops production for growers in Africa. Soils in the arid and semi-arid regions like South Africa have little nutrient and mineral contents, which adversely affect plant growth and quality. Therefore, the objectives of the study were to determine the effects of sole and combined applications of Effective Microorganisms enriched compost, broiler manure and inorganic (NPK) fertiliser applications, on growth and yield of three tomato varieties and to assess the influence of the applied fertiliser on nutritional composition of three tomato varieties. Field experiments were conducted at Horticultural skill centre, University of Limpopo (Mankweng), and at Mphebatho farm, Apel, Limpopo province, South Africa. The experiment was laid out in a 7 x 3 split-plot design. Recommended amount of organic and inorganic fertilisers was used. The treatments were: control (without fertiliser application), NPK (2:3:4(30) at a rate of 200 N ha-1, 260 P ha-1 and 257 K ha-1, applied as N from Urea, P from superphosphate and K from potassium chloride (KCl), mineralised broiler manure (10 000 kg ha-1), ½ NPK + ½ broiler manure rates, EM enriched compost (14 m3 ha-1), ½ EM compost + ½ NPK rates, and ½ EM compost + ½ broiler manure rates. Three tomato varieties (Floradade, Roma and Moneymaker) seedlings were transplanted using standard spacing of 30 x 60 cm. Chlorophyll contents of leaves, biomass production, plant height, fruit number, stem diameter and branch number were determined after six weeks of transplanting and fortnightly thereafter. The interactions between tomato varieties and fertiliser materials with regard to plant height were not significant (P ≤ 0.05) at both sites (Apel and Mankweng). Average plant height (63.75 cm) obtained in Moneymaker grown in EM compost treatment was significantly highest at Apel, for Floradade (42.25 cm) in broiler manure treatment while that of Roma variety (39.63 cm) was found in ½ EM compost + ½ NPK treatment at 8 WAT. Similar trend was also recorded at 10 WAT. For Mankweng the significantly (P ≤ 0.05) highest average plant height at 8 WAT (66.63 cm) was obtained in Moneymaker grown in ½ broiler manure + ½ NPK treatment for Floradade (45.63 cm) obtained in broiler manure treatment, and 44.50 cm recorded for Roma in broiler manure treatment. Similar trend was also followed at 10 WAT. At vi Apel, significantly highest average number of tomato fruits at 8, 10 and 12 WAT were recorded in treatment with ½ EM + ½ NPK while the least values were found in control. Whereas at Mankweng the variation in number of tomato fruits under different fertiliser treatments were not significant. Similar, non-significant interactions (V x F) for tomato shoot nutritional composition were found in tomato grown at both sites (Apel and Mankweng) in relation to fertiliser treatments. At Apel however, comparing the fertiliser treatments, tomato grown in soil treated with ½ broiler manure + ½ NPK had the significantly highest average (3.01 %) K content while the least value (2.65 %) was obtained in the control. Similarly, significantly highest mean (44.33 mg kg-1) Zn was found in crops grown in the same treatment, but the lowest significant value (36.50 mg kg-1) was obtained in ½ EM + ½ NPK treatment. For Mn and Fe contents in tomato significantly highest mean values (150.17 mg kg-1 and 2381 mg kg-1) for Mn and Fe respectively were found in sole broiler manure treatment while the least values 114.83 mg kg-1 and 1357.6 mg kg-1 for Mn and Fe respectively were found in ½ EM + ½ NPK and sole NPK treatments respectively. It may be concluded that in tomato production, combined application of organic and inorganic sources of nutrients can be more beneficial and can be adopted by smallholder farmers with limited resources. / DAFF Zero hunger
15

The environmental risks linked to different manure application periods /

Cantin, Jean. January 2006 (has links)
No description available.
16

Design and evaluation of liquid swine manure injectors for potato nutrient placement

Campbell, Allan J. January 1998 (has links)
No description available.
17

Deep-placed phosphate fertiliser improves phosphorus uptake and seed yield of canola (Brassica napus L.) in a Mediterranean-type climate

Rose, Terry January 2008 (has links)
In Mediterranean-type climates, topsoil frequently dries out during spring. Problems associated with reduced nutrient (P, K) availability in dry topsoil may be overcome by placing fertilisers deeper in the soil, where the soil is more likely to remain moist for longer periods as opposed to conventional fertiliser placement. Deep-P placement has resulted in significant yield improvements for lupin crops in Mediterranean environments because lupin crops generally require soil P supply during spring (throughout the flowering stage); in contrast, wheat yields have seldom improved with deep P placement, presumably because plants have accumulated sufficient P prior to spring (grain filling stage) for maximum grain yields. The P and K accumulation patterns of canola had not been investigated, and therefore any potential yield benefits of deep placed fertilisers were unknown. This study aimed to define the P and K demands of canola throughout the growing season, and assess the viability of deep placement of fertiliser in matching soil P and K supply to crop demand. The study further investigated the impact of deep placement of P fertiliser on root growth and distribution throughout the soil profile. Initial glasshouse studies compared the P and K accumulation patterns of several canola cultivars with wheat, and found that the P and K demand of canola continued until later into the season than wheat, but there was little difference in the P and K accumulation patterns of the various canola cultivars. Further experiments in sand culture determined that regardless of the level of K supply, canola plants had accumulated sufficient K for maximum seed yields by early flowering. Under high P supply, canola plants had accumulated enough P for maximum seed yields by early flowering, but when P supply during vegetative growth was just adequate, plants required a continual P supply until mid silique-filling to attain maximum yields. Because plants had accumulated sufficient K for maximum seed yields by early flowering (therefore topsoil drying in spring was unlikely to affect yields), further field experiments examined only deep placement of P fertiliser to improve P uptake and yields.
18

Produção animal em sistema de integração lavoura-pecuária em função de intensidade de pastejo e antecipação de adubação nitrogenada / Animal production in crop-livestock integration system as result of grazing intensity and nitrogen fertilizer anticipation

Rissi, Bruno Felipe 22 June 2015 (has links)
CNPq; CAPES / A integração lavoura-pecuária permite uma diversificação de culturas no sistema e aumento na produtividade por unidade de área, o que confere maior renda ao produtor e eficiência no uso de insumos. A sucessão aveia preta consorciada com azevém vem sendo amplamente utilizada nesse sistema. Contudo a maioria dos produtores não aplica fertilizantes na pastagem pois considera que a ocorrência de efeito residual da adubação realizada não é eficiente para cultura sucessora. O objetivo deste trabalho foi identificar o efeito residual da aplicação de adubação nitrogenada realizada na cultura antecessora da pastagem e o efeito de diferentes alturas de pastejo sobre o desempenho, comportamento ingestivo dos animais e composição química da forragem no período de inverno/ primavera do ano de 2014. O trabalho foi conduzido na Fazenda Pacheco, localizada no município de Abelardo Luz-SC coordenadas, latitude: 26,5672, longitude: -52,3339. O delineamento experimental foi blocos ao acaso, num esquema fatorial 2x2 com três repetições. O primeiro fator foi Tempo de adubação nitrogenada: N-pastagem 200 kg ha-1 e N-Grãos. O segundo fator foi a Altura de Pastejo, caracterizada por Alta Altura de Pastejo (30 cm) e Baixa Altura de Pastejo (15 cm). A aplicação de adubações nitrogenada na lavoura de milho em sistema de integração lavoura-pecuária no sul do Brasil não apresenta efeito residual sobre o desempenho das pastagens ocasionando menor produção animal. A adubação nitrogenada quando aplicada na pastagem exerce efeito no aumento na produção de matéria seca da pastagem proporcionando maior carga animal porém não altera os teores qualitativos da pastagem. A altura de manejo da pastagem interfere diretamente no comportamento ingestivo dos bovinos os quais necessitam de mais tempo de pastejo quando submetidos a baixas alturas de manejo. / The crop-livestock integration allows crops diversification in system and increased productivity per unit area, which gives higher income to producer and the efficient use of inputs. The black oat intercropped with ryegrass succession - has been widely used in this system. However, most producers don´t apply fertilizer on shieling considering that fertilization´s residual carried out effect isn´t efficient successor to culture. The study´s objective is to find the residual effect of the nitrogen fertilization´s application carried out in preceding crop grassland and the effect of different heights grazing on performance, animals' feeding behavior and chemical forage´s composition during winter / spring of the year 2014. The job was conducted at Fazenda Pacheco, located in the city of Abelardo Luz-SC coordinates, latitude: 26.5672, longitude: -52.3339. The experimental design was randomized blocks in a 2x2 factorial plan with three replications. The first factor was nitrogen fertilization Time: N-grazing 200 kg ha-1 and N-grains. The second factor was the grazing height, characterized by high grazing height (30 cm) and Low grazing height (15 cm). Nitrogen fertilization´s application in maize crop in crop-livestock integration system in southern Brazil has no residual effect on the pastures' performance leading to lower animal production. Nitrogen fertilization when applied on grassland has an effect on the increase in dry matter production of the pasture providing greater stocking rate but doesn't change the pasture´s qualitative content. The pasture management tall interfere directly in the cattle´s feeding behavior which require more grazing time when subjected to low sward heights.
19

Produção animal em sistema de integração lavoura-pecuária em função de intensidade de pastejo e antecipação de adubação nitrogenada / Animal production in crop-livestock integration system as result of grazing intensity and nitrogen fertilizer anticipation

Rissi, Bruno Felipe 22 June 2015 (has links)
CNPq; CAPES / A integração lavoura-pecuária permite uma diversificação de culturas no sistema e aumento na produtividade por unidade de área, o que confere maior renda ao produtor e eficiência no uso de insumos. A sucessão aveia preta consorciada com azevém vem sendo amplamente utilizada nesse sistema. Contudo a maioria dos produtores não aplica fertilizantes na pastagem pois considera que a ocorrência de efeito residual da adubação realizada não é eficiente para cultura sucessora. O objetivo deste trabalho foi identificar o efeito residual da aplicação de adubação nitrogenada realizada na cultura antecessora da pastagem e o efeito de diferentes alturas de pastejo sobre o desempenho, comportamento ingestivo dos animais e composição química da forragem no período de inverno/ primavera do ano de 2014. O trabalho foi conduzido na Fazenda Pacheco, localizada no município de Abelardo Luz-SC coordenadas, latitude: 26,5672, longitude: -52,3339. O delineamento experimental foi blocos ao acaso, num esquema fatorial 2x2 com três repetições. O primeiro fator foi Tempo de adubação nitrogenada: N-pastagem 200 kg ha-1 e N-Grãos. O segundo fator foi a Altura de Pastejo, caracterizada por Alta Altura de Pastejo (30 cm) e Baixa Altura de Pastejo (15 cm). A aplicação de adubações nitrogenada na lavoura de milho em sistema de integração lavoura-pecuária no sul do Brasil não apresenta efeito residual sobre o desempenho das pastagens ocasionando menor produção animal. A adubação nitrogenada quando aplicada na pastagem exerce efeito no aumento na produção de matéria seca da pastagem proporcionando maior carga animal porém não altera os teores qualitativos da pastagem. A altura de manejo da pastagem interfere diretamente no comportamento ingestivo dos bovinos os quais necessitam de mais tempo de pastejo quando submetidos a baixas alturas de manejo. / The crop-livestock integration allows crops diversification in system and increased productivity per unit area, which gives higher income to producer and the efficient use of inputs. The black oat intercropped with ryegrass succession - has been widely used in this system. However, most producers don´t apply fertilizer on shieling considering that fertilization´s residual carried out effect isn´t efficient successor to culture. The study´s objective is to find the residual effect of the nitrogen fertilization´s application carried out in preceding crop grassland and the effect of different heights grazing on performance, animals' feeding behavior and chemical forage´s composition during winter / spring of the year 2014. The job was conducted at Fazenda Pacheco, located in the city of Abelardo Luz-SC coordinates, latitude: 26.5672, longitude: -52.3339. The experimental design was randomized blocks in a 2x2 factorial plan with three replications. The first factor was nitrogen fertilization Time: N-grazing 200 kg ha-1 and N-grains. The second factor was the grazing height, characterized by high grazing height (30 cm) and Low grazing height (15 cm). Nitrogen fertilization´s application in maize crop in crop-livestock integration system in southern Brazil has no residual effect on the pastures' performance leading to lower animal production. Nitrogen fertilization when applied on grassland has an effect on the increase in dry matter production of the pasture providing greater stocking rate but doesn't change the pasture´s qualitative content. The pasture management tall interfere directly in the cattle´s feeding behavior which require more grazing time when subjected to low sward heights.
20

Development of an expert system for irrigation and fertilization management in the Pacific Northwest

Cao, Weidong 23 October 1992 (has links)
Recent advances in computer technology have made possible the development of expert systems. Expert systems are computer programs that perform at the level of a human expert. Expert systems can help integrate and apply diverse sources of information and expertise to problems of integrated crop management. A prototype Crop Management eXpert (CMX) system has been developed. The primary goal of CMX is to provide recommendations on optimal irrigation and fertilization scheduling for wheat production in the Pacific Northwest. This system can be used by farmers and/or extension agents. OUS II Shell has been used as a implementation tool. To build this rule - based expert system, a development strategy, commonly used in the construction of expert systems, consisting of 1 ) identification; 2) conceptualization; 3) formalization; 4) implementation; and 5) testing was applied. CMX is composed of modules for irrigation and fertilization management. For irrigation management, CMX is mainly involved in the irrigation scheduling which is the major part of irrigation management. Irrigation strategies have been applied in irrigation decision making. For each strategy, timing criteria which generally consist of management allowed depletion, soil water potential, leaf water potential, and water stress indices have been used. The system provides farmers with irrigation scenarios which determine when and how much water to apply. CMX represents an integration of conventional computing and expert systems technology designed to provide expert recommendations enabling farmers to obtain the best return on their water and fertilizer investment. For fertilization management, a variety of variables have been taken into considered. Crop growth stages, soil moisture, nutrient analysis, protein requirement, and application methods are important factors for the fertilizer decision making. Several constraints have been used in optimal fertilizer advice. CMX can focus only on relevant information, thus reducing the problem space to a manageable size and significantly, improving the efficiency of the system. The facility of the expert system to explain the decision-making process enables users to better understand the underlying assumptions, facts, and reasoning used to generate recommendations. The CMX prototype demonstrates the feasibility of employing expert systems technology in agricultural applications. CMX has been validated and evaluated. The survey results showed that this prototype was successful in capturing domain experts' knowledge as rules and providing advice on the irrigation and fertilization management for wheat. / Graduation date: 1993

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