Concentrated animal feeding operations (CAFOs) have caused water quality concerns in many rural watersheds, sometimes forcing the State of Texas to conduct Total Maximum Daily Load (TMDL) assessments of stream nutrients such as nitrogen (N) and phosphorus (P). One suggested Best Management Practice (BMP) is the export of phosphorus (P) through turfgrass sod produced with composted dairy manure from an impaired rural watershed to an urban watershed. The manure-grown sod releases P slowly and would not require additional P fertilizer for up to 20 years in the receiving watershed. This would eliminate P application to the sod and improve the water quality of urban streams. The Soil and Water Assessment Tool (SWAT) was used to model a typical suburban watershed that would receive the transplanted sod. The objective of the modeling was to determine the water quality changes due to the import of sod transplanted from turf fields and grown with composted dairy manure. The SWAT model was calibrated to simulate historical flow and sediment and nutrient loading to Mary's Creek. The total P stream loading to Mary's Creek was lower when manure-grown sod was imported instead of commercial sod grown with inorganic fertilizers. Yet, flow, sediment yield, and total N yield increased equally for both cases at the watershed outlet. The SWAT simulations indicate that a turfgrass BMP can be used effectively to import manure P into an urban watershed and reduce in-stream P levels when compared to sod grown with inorganic fertilizers.

Thesis (M.S.)--Indiana University, 2007. / Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Philippe G. Vidon, Lenore P. Tedesco, Kathy J. Licht. Includes vitae. Includes bibliographical references (leaves 110-114).

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-10-23T14:05:53Z No. of bitstreams: 1 Dissertação - Erilene Romeiro Alves.pdf: 1043331 bytes, checksum: bd57a06c9068cd1af6cb6450d2ae8819 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-26T19:02:29Z (GMT) No. of bitstreams: 1 Dissertação - Erilene Romeiro Alves.pdf: 1043331 bytes, checksum: bd57a06c9068cd1af6cb6450d2ae8819 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-26T19:04:36Z (GMT) No. of bitstreams: 1 Dissertação - Erilene Romeiro Alves.pdf: 1043331 bytes, checksum: bd57a06c9068cd1af6cb6450d2ae8819 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-26T19:08:25Z (GMT) No. of bitstreams: 1 Dissertação - Erilene Romeiro Alves.pdf: 1043331 bytes, checksum: bd57a06c9068cd1af6cb6450d2ae8819 (MD5) / Made available in DSpace on 2015-10-26T19:08:25Z (GMT). No. of bitstreams: 1 Dissertação - Erilene Romeiro Alves.pdf: 1043331 bytes, checksum: bd57a06c9068cd1af6cb6450d2ae8819 (MD5) Previous issue date: 2015-05-14 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / The guarana culture in the Amazon region has great economic and social importance, but there is a lack of information regarding the sampling of foliage and nutritional evaluation of the plants. In this sense, this research aimed to standardize the time, leaves positions in the branch and leaflet position on the composite sheet for leaf sampling and evaluate the correlation between nutrients in the soil, leaves and fruit and the nutrient accumulation in the fruit. The experiment was conducted in AmBev's facilities on the farm St. Helens in Maues, AM. The experimental design was a randomized block with four replications. The leaves for the samples were taken in early position, middle and end in guarana branch, five positions of the leaflets 1st, 2nd, 3rd, 4th and 5th at four different times: August and November 2013; February and May 2014. The evaluation of guarana productivity, was the fruiting period and quantified the macro and micronutrients from soil, leaves and grains. The epochs did not affect the content in N sampling, Ca, S, Cu, Zn, with the exception of P, K, Mg indicated in February 2014 (vegetative period), B in May 2014 (vegetative period) and Fe and Mn in November 2013 (fructification period). The leaves of mineral levels in the final position in the business, with the exception of N from the home position and the position of the leaflets 4th and 5th reflected better the nutritional status of guaranazeiro. Os levels of nutrients in the leaves and grains correlated well. The concentration of most nutrients extracted by the plant fruits obeyed the following order: N> K> Ca> Mg> P> S> Fe> Zn> Mn> Cu> B. / A cultura do guaranazeiro na região amazônica tem grande importância econômica e social, porém há carência de informações em relação à amostragem foliar e avaliação nutricional das plantas. Nesse sentido, esta pesquisa teve o objetivo de padronizar a época, posição da folha no ramo e posição do folíolo na folha composta para amostragem foliar e avaliar a correlação entre os nutrientes no solo, folhas e frutos e o acúmulo de nutrientes no fruto. O experimento foi conduzido nas instalações da AmBev, na fazenda Santa Helena, em Maués, AM. O delineamento experimental foi em blocos ao acaso, com quatro repetições. As folhas para a amostragens foram retiradas nas posições inicial, média e final no ramo do guaranazeiro, cinco posições dos folíolos 1°, 2°, 3°, 4° e 5° em quatro diferentes épocas: agosto e novembro de 2013; fevereiro e maio de 2014. A avaliação da produtividade do guaranazeiro foi no período de frutificação e quantificados os teores de macro e micronutrientes do solo, folhas e grãos. As épocas não influenciaram os teores na amostragem de N, Ca, S, Cu, Zn, com exceção de P, K, Mg indicado em fevereiro de 2014 (período vegetativo), B em maio de 2014 (período vegetativo) e Fe e Mn em novembro de 2013 (período de frutificação). Os teores dos minerais das folhas na posição final no ramo, com exceção do N na posição inicial e na posição dos folíolos 4° e 5° refletiram melhor o estado nutricional do guaranazeiro. Os teores dos nutrientes nas folhas e grãos tiveram boa correlação. As concentrações de nutrientes mais extraídas da planta pelos frutos obedeceram a seguinte ordem: N>K>Ca>Mg>P>S>Fe>Zn>Mn>Cu>B.

Made available in DSpace on 2016-08-12T19:15:34Z (GMT). No. of bitstreams: 1 JeizaCM_DISSERT.pdf: 490536 bytes, checksum: 937d41b0f6174d8289051e96e70510a5 (MD5) Previous issue date: 2015-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Knowledge of a crop's growth rate and nutrient accumulation rate is very important for establishing a program of split applications of the recommended total nutrient rates. This study aimed to measure the rate of accumulation and export of dry matter and nutrients by a corn hybrid irrigated under the climatic conditions of the Apodi Plateau. An experiment was carried out in the field in the town of Quixeré, Ceará, Brazil, using the cultivar AG 1051. Ten treatments were applied, resulting from combinations between five rates of N (0, 45, 90, 160 and 220 kg ha-1) and four rates of P2O5 (0, 40, 80, and 120 kg ha-1). The experimental design was a randomized complete block with four replications. In this experiment, a benchmark treatment was chosen (90 kg ha-1 of N + 40 kg ha-1 of P2O5) for completion of sampling. The plants were sampled at 26, 33, 39, 47, 53, 61 and 71 days after sowing, and cut at ground level for evaluation of shoots. Ear and straw were separated at harvest. The following characteristics were evaluated: plant height, stem diameter and accumulation of N, P, K, Ca, Mg, S, B and Zn in the shoots. At the time of harvest at 71 days after sowing (DAS), the levels of these nutrients were also evaluated separately in the ear and in the remainder of the shoot of the plants. Stem diameter showed maximum value at 45 days after sowing (DAS); plant height showed a higher value at the end of the growing period, at 71 DAS. Accumulation of fresh and dry matter, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron and zinc showed higher values at 71 DAS. At the time of harvest, the descending order of nutrient accumulation in the shoots was: potassium > nitrogen > calcium > sulfur > phosphorus > magnesium > zinc > boron. In the ear, this order was: potassium > nitrogen > phosphorus > calcium > magnesium > sulfur > zinc > boron / O conhecimento da marcha de crescimento e de acúmulo de nutrientes de uma cultura é muito importante para o estabelecimento de um programa de parcelamento das doses totais recomendadas de nutrientes. Este trabalho teve como objetivo realizar a marcha de acúmulo e a exportação de matéria seca e de nutrientes por um híbrido de milho irrigado nas condições edafoclimáticas da Chapada do Apodi. Foi instalado um experimento em campo no município de Quixeré-CE, utilizando a cultivar AG 1051. Foram aplicados dez tratamentos resultantes de combinações entre cinco doses de N (0, 45, 90, 160 e 220 kg ha-1) e quatro doses de P2O5 (0, 40, 80, e 120 kg ha-1), no delineamento experimental de blocos ao acaso com quatro repetições. Neste experimento, foi escolhido um tratamento de referência (90 kg ha-1 de N + 40 kg ha-1 de P2O5) para realização das amostragens. As plantas foram amostradas aos 26, 33, 39, 47, 53, 61 e 71 dias após a semeadura, cortadas no nível do solo para avaliação da parte aérea e, por ocasião da colheita foram separadas em espiga e palhada. As características avaliadas foram: altura da planta, diâmetro de caule e acúmulo de N, P, K, Ca, Mg, S, B e Zn na parte aérea. Por ocasião da colheita aos 71 dias após a semeadura (DAS), também foram avaliados separadamente os conteúdos desses nutrientes na espiga e no restante da parte aérea da planta. O diâmetro do caule apresentou valor máximo aos 45 dias após a semeadura (DAS), a altura de planta apresentou maior valor no final do período de cultivo, aos 71 DAS, os acúmulos de matéria fresca e seca, assim como de nitrogênio, fósforo, potássio, cálcio, magnésio, enxofre, boro e zinco apresentaram maiores valores aos 71 DAS. Por ocasião da colheita, a ordem decrescente de acúmulo de nutrientes na parte aérea foi: potássio > nitrogênio > cálcio > enxofre > fósforo > magnésio > zinco > boro. Nas espigas, essa ordem foi: potássio > nitrogênio > fósforo > cálcio > magnésio > enxofre > zinco > boro

Made available in DSpace on 2016-08-12T19:18:51Z (GMT). No. of bitstreams: 1 JeizaCM_DISSERT.pdf: 490536 bytes, checksum: 937d41b0f6174d8289051e96e70510a5 (MD5) Previous issue date: 2015-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Knowledge of a crop's growth rate and nutrient accumulation rate is very important for establishing a program of split applications of the recommended total nutrient rates. This study aimed to measure the rate of accumulation and export of dry matter and nutrients by a corn hybrid irrigated under the climatic conditions of the Apodi Plateau. An experiment was carried out in the field in the town of Quixeré, Ceará, Brazil, using the cultivar AG 1051. Ten treatments were applied, resulting from combinations between five rates of N (0, 45, 90, 160 and 220 kg ha-1) and four rates of P2O5 (0, 40, 80, and 120 kg ha-1). The experimental design was a randomized complete block with four replications. In this experiment, a benchmark treatment was chosen (90 kg ha-1 of N + 40 kg ha-1 of P2O5) for completion of sampling. The plants were sampled at 26, 33, 39, 47, 53, 61 and 71 days after sowing, and cut at ground level for evaluation of shoots. Ear and straw were separated at harvest. The following characteristics were evaluated: plant height, stem diameter and accumulation of N, P, K, Ca, Mg, S, B and Zn in the shoots. At the time of harvest at 71 days after sowing (DAS), the levels of these nutrients were also evaluated separately in the ear and in the remainder of the shoot of the plants. Stem diameter showed maximum value at 45 days after sowing (DAS); plant height showed a higher value at the end of the growing period, at 71 DAS. Accumulation of fresh and dry matter, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron and zinc showed higher values at 71 DAS. At the time of harvest, the descending order of nutrient accumulation in the shoots was: potassium > nitrogen > calcium > sulfur > phosphorus > magnesium > zinc > boron. In the ear, this order was: potassium > nitrogen > phosphorus > calcium > magnesium > sulfur > zinc > boron / O conhecimento da marcha de crescimento e de acúmulo de nutrientes de uma cultura é muito importante para o estabelecimento de um programa de parcelamento das doses totais recomendadas de nutrientes. Este trabalho teve como objetivo realizar a marcha de acúmulo e a exportação de matéria seca e de nutrientes por um híbrido de milho irrigado nas condições edafoclimáticas da Chapada do Apodi. Foi instalado um experimento em campo no município de Quixeré-CE, utilizando a cultivar AG 1051. Foram aplicados dez tratamentos resultantes de combinações entre cinco doses de N (0, 45, 90, 160 e 220 kg ha-1) e quatro doses de P2O5 (0, 40, 80, e 120 kg ha-1), no delineamento experimental de blocos ao acaso com quatro repetições. Neste experimento, foi escolhido um tratamento de referência (90 kg ha-1 de N + 40 kg ha-1 de P2O5) para realização das amostragens. As plantas foram amostradas aos 26, 33, 39, 47, 53, 61 e 71 dias após a semeadura, cortadas no nível do solo para avaliação da parte aérea e, por ocasião da colheita foram separadas em espiga e palhada. As características avaliadas foram: altura da planta, diâmetro de caule e acúmulo de N, P, K, Ca, Mg, S, B e Zn na parte aérea. Por ocasião da colheita aos 71 dias após a semeadura (DAS), também foram avaliados separadamente os conteúdos desses nutrientes na espiga e no restante da parte aérea da planta. O diâmetro do caule apresentou valor máximo aos 45 dias após a semeadura (DAS), a altura de planta apresentou maior valor no final do período de cultivo, aos 71 DAS, os acúmulos de matéria fresca e seca, assim como de nitrogênio, fósforo, potássio, cálcio, magnésio, enxofre, boro e zinco apresentaram maiores valores aos 71 DAS. Por ocasião da colheita, a ordem decrescente de acúmulo de nutrientes na parte aérea foi: potássio > nitrogênio > cálcio > enxofre > fósforo > magnésio > zinco > boro. Nas espigas, essa ordem foi: potássio > nitrogênio > fósforo > cálcio > magnésio > enxofre > zinco > boro

Indiana University-Purdue University Indianapolis (IUPUI) / This study investigated nutrient export during three spring storm events in two different land use watersheds (agricultural and mixed land use) in a glacial till landscape of the Midwestern, USA. The objectives of the study were: (1) to determine how land use affects water, nitrate, soluble reactive phosphorus (SRP) and dissolved organic carbon (DOC) delivery (timing, amount) to streams during spring storms in two central Indiana watersheds with contrasting land use; and (2) to determine nitrate, SRP and DOC flow pathways to streams during spring storms. High frequency stream sampling of nutrients and cations, coupled with hydrograph separations using δ18O, was used to identify water flow pathways and event and pre-event water contributions to the streams. Data indicate land use and storm characteristics play a role in the export of water and nutrients. In the agricultural watershed (Watershed A), the storm hydrograph is dominated by pre-event water, whereas the mixed land use watershed (Watershed M) storm hydrograph is more event water dominated. Watershed A also contains higher nutrient concentrations, especially nitrate. High bulk precipitation and greater maximum intensity export more nitrate, SRP, and DOC to the streams. Results also indicate nitrate, DOC, and SRP concentrations display distinct temporal patterns during spring storm events. DOC concentration increased with stormflow and peaked on the rising limb/with maximum discharge regardless of land use or storm event. In Watershed A, SRP concentration followed a similar pattern to DOC during small storms; therefore they are believed to be exported together with flushing of saturated near-surface soil waters via macropores/overland flow. However, SRP likely has multiple flowpaths, one dominated over another depending on the storm. Nitrate concentrations matched Ca2+, Mg2+, and Na+ trajectories and decreased with stormflow, suggesting a tile drain/subsurface flowpath. Nitrate and SRP peak concentrations are delayed relative to DOC in Watershed M. The wet retention ponds in the headwaters are believed to delay the stormflow response, and therefore, the delivery of nutrients to the stream.

Durch ihre Umwelt- und Nährwertvorteile erweckten Afrikanische indigene Blattgemüse – „African Indigenous Vegetables“ (AIV) in letzter Zeit Aufmerksamkeit als „Supergemüse“ (Cernansky 2015). Da mehrere Spezies aus unterschiedlichen botanischen Familien innerhalb der AIVs vertreten sind, ist ein besseres Verständnis Spezies spezifischer Eigenschaften, wie z.B. Ernährungswert und agronomischem Management nötig, um diese Vorteile voll ausschöpfen zu können. In dieser Arbeit haben wir Afrikanisch indigene Blattgemüsearten aus fünf Familien, inklusive C3 and C4 Spezies und Leguminosen und nicht-Leguminosen (Brassica carinata/Cruciferae - Ethiopian Kale, Amaranthus cruentus/Amaranthaceae - Amaranth, Vigna unguiculata/Leguminosae - Cowpea, Solanum scabrum/Solanaceae - African Nightshade, Cleome gynandra/Capparaceae - Spiderplant) mit einer importierten und in Kenia häufig angebauten Gemüseart (Brassica oleracea acephala/Cruciferae - Exotic Kale) verglichen. Wir betrachteten die Pflanzenarten hinsichtlich ihrer Konzentrationen an wertgebenden und toxischen Elementen in Blättern als Index für den Nährwert, ihrer Reaktionen auf unterschiedliche zur Verfügung gestellten Mengen und Formen an Phosphor (P) als Index für die Adaptation an suboptimale chemische Bodenbedingungen und ihre erntebedingten Nährstoffausfuhren aus dem Boden als Index für den Düngerbedarf. Die Arbeit war in das interdisziplinäre Forschungsprogramm HORTINLEA (Horticultural Innovation and Learning for Improved Nutrition and Livelihood in East Africa) eingebunden. / African Indigenous Vegetables (AIVs) have recently captured considerable attention as “super vegetables” due to their nutritional and environmental benefits (Cernansky 2015). As AIVs include many species belonging to different botanical families, more species-specific knowledge e.g. on nutritional value and agronomic management is needed to fully exploit those benefits. In this thesis we compared leafy AIV species from five families including C3 and C4 species, and a legume and non-legume species (Brassica carinata/Cruciferae - Ethiopian kale, Amaranthus cruentus/Amaranthaceae - amaranth, Vigna unguiculata/Leguminosae cowpea, Solanum scabrum/Solanaceae - African nightshade, Cleome gynandra/Capparaceae - spider plant) with a non-indigenous species, which is commonly grown in Kenya (Brassica oleracea acephala/Cruciferae - “exotic kale”). We compared the leaf concentrations of beneficial nutrients and heavy metals as an index for the nutritional value, the performance under different rates and forms of phosphorus (P) supply as an index for adaptation to suboptimal chemical soil conditions, and the harvest-related nutrient outflow from soil as an index for fertilizer need. The thesis was embedded in the interdisciplinary research program HORTINLEA (Horticultural Innovation and Learning for Improved Nutrition and Livelihood in East Africa).

Made available in DSpace on 2017-07-25T19:30:49Z (GMT). No. of bitstreams: 1 Allison Jose Fornari.pdf: 1614252 bytes, checksum: 1528c75fb76d8cae0fcfb0d22642bbe1 (MD5) Previous issue date: 2014-07-31 / Nitrogen (N) and potassium (K) are nutrients required in larger amounts by corn, requiring adequate levels of N and K phases of higher demand culture. This study aimed to evaluate the effects of fertilization with N and K nutrition, performance and productivity of maize in long-term tillage system. The experiment was carried out on a Yellow Red Oxisol dystrophic with 530 g kg-1 clay under no-till for 30 years. The sequence of crops adopted before the establishment of the experiment was oat/corn/wheat/soybean/wheat/soybean with the annual crop of oat/corn in 33% of the area and wheat/soybean in 67% of the area. A randomized complete block design was used, with three replications in a split-plot arrangement. The treatments consisted of applications of urea at 0, 75, 150, and 225 kg N ha-1 to subplots within plots with KCl previously at 0, 100, 200, and 300 kg K ha-1. The K rates were applied on the surface before seeding, and the N rates were applied in top dressing when corn plants were at the V4 stage (four fully expanded leaves). The Ca/K, Ca + Mg/K, and √ relationships in the topsoil (0-0.20 m) were linearly reduced with increasing rates of K applied pre-sowing. There was no significant effect of increasing K rates on concentrations of N, P, K, Ca, Mg, S, Mn, Zn, Cu and Fe in corn leaves, dry weight of shoots and grains of corn. The increase in N rates increased the contents of N, P, K, Ca, Mg, S, Mn and Zn in the leaves of corn at the silking stage, increased the concentration of N and decreased the content of P, K, Mn, Zn, and Fe in the aboveground part and increased the concentrations of N, P, K, S, Mn, Zn, and Fe in corn grains. The increasing rates of K increased the extraction of K, while the N rates increased the extraction of N, P, K, Ca, Mg, S, Mn, Zn, and Cu by corn shoots. The export of N, P, K, Ca, Mg, S, Mn, Zn, Cu, and Fe was not affected by K rates, but increased with increasing rates of N applied in corn. Potassium fertilization increased plant height and ear height. Increasing N rates increased stem diameter, plant height and ear height, the dry matter production of shoots, the number of kernels per row and per spike, spike and the mass of the mass 1000 grains. Potassium rates did not significantly influence corn grain yield, while increasing rates of N reached double the corn yield. The N use efficiency decreased with increasing N rates in corn and has not improved with potassium fertilization. The relative grain yield of corn was closely related to foliar N, P, Mg and S. The relative grain yield of corn had closer relations with the products N × P, N × K, and N × S than with N/P, N/K, and S/N ratio in leaf tissue of corn. The results suggest that the high demand of N by corn grown after oat under no-till does not increase the demand for K fertilization in corn, in soil with sufficient content of exchangeable K in the 0-0.20 m layer. / O nitrogênio (N) e o potássio (K) são os nutrientes exigidos em maiores quantidades pela cultura do milho, sendo necessárias quantidades adequadas de N e K nas fases de maior demanda da cultura. O presente trabalho teve o objetivo de avaliar os efeitos da adubação com N e K na nutrição, no desempenho e na produtividade da cultura do milho em sistema plantio direto de longa duração. O experimento foi realizado em um Latossolo Vermelho Amarelo distrófico com 530 g kg-1 de argila, conduzido em sistema de plantio direto por 30 anos. A sequência de culturas adotada antes da instalação do experimento foi aveia/milho/trigo/soja/trigo/soja, com cultivo anual de aveia/milho em 33% da área e de trigo/soja em 67% da área. O delineamento experimental empregado foi em blocos ao acaso, em esquema de parcelas subdivididas, com três repetições. Nas parcelas foram aplicados 100, 200 e 300 kg ha-1 de K, além de um tratamento controle sem K. Nas subparcelas foram empregados 75, 150 e 225 kg ha-1 de N, além de um tratamento controle sem N. As doses de K foram aplicadas na forma de KCl, a lanço em pré-semeadura, e as de N foram aplicadas na forma de ureia, em cobertura, quando as plantas de milho estavam no estádio V4 (quatro folhas completamente expandidas). As relações Ca/K, Ca+Mg/K e √ no solo (0–0,20 m) foram linearmente reduzidas com o aumento das doses de K aplicadas em pré-semeadura. Não houve efeito significativo do aumento das doses de K sobre as concentrações de N, P, K, Ca, Mg, S, Mn, Zn, Cu e Fe nas folhas de milho, na massa seca da parte aérea e nos grãos do milho. O incremento de doses de N aumentou os teores de N, P, K, Ca, Mg, S, Mn e Zn nas folhas de milho na fase de florescimento, aumentou a concentração de N e diminuiu os teores de P, K, Mn, Zn e Fe na matéria seca da parte aérea, e aumentou as concentrações de N, P, K, S, Mn, Zn e Fe nos grãos de milho. O incremento das doses de K aumentou a extração de K, enquanto as doses de N aumentaram a extração de N, P, K, Ca, Mg, S, Mn, Zn e Cu pela parte aérea do milho. A exportação de N, P, K, Ca, Mg, S, Mn, Zn, Cu e Fe não foi alterada pelas doses de K, porém aumentou com o incremento de doses de N aplicadas na cultura do milho. As doses de K aumentaram a altura das plantas e de inserção da espiga. O aumento das doses de N aumentou o diâmetro de colmo, a altura das plantas e de inserção da espiga, a produção de matéria seca da parte aérea, o número de grãos por fileira e por espiga, a massa da espiga e a massa de 1000 grãos. As doses de K não influenciaram significativamente a produtividade de grãos de milho, enquanto que o aumento das doses de N chegou a dobrar a produtividade de grãos do milho. A eficiência de utilização de N diminuiu com o incremento das doses de N aplicadas em cobertura e não melhorou com adubação potássica na cultura do milho. A produtividade relativa de grãos de milho esteve estreitamente relacionada com os teores foliares de N, P, Mg e S. A produtividade relativa de grãos de milho apresentou relações mais estreitas com os produtos N × P, N × K e N × S do que com as relações N/P, N/K e N/S no tecido foliar do milho. Os resultados sugerem que a alta demanda de N pelo milho cultivado após aveia preta no sistema plantio direto não aumenta a demanda de K na adubação do milho, em solo com teor suficiente de K trocável na camada de 0–0,20 m.

Potatoes (Solanum tuberosum) were grown in a fine sandy loam soil in southern Manitoba in a three-year field study comparing four water management treatments: No Drainage with No Irrigation (NDNI), No Drainage with Overhead Irrigation (NDIR), Free Drainage with Overhead Irrigation (FDIR), and Controlled Drainage with Subirrigation (CDSI). The objectives of the study were (i) to evaluate the effect of the four treatments on yield and quality of potatoes, (ii) to evaluate the effect of water management on the environment, (iii) to estimate the shallow groundwater contribution to potato water requirement, and (iv) to simulate the shallow groundwater hydrology using the DRAINMOD and HYDRUS 1-D model. Subsurface drains were installed at 0.9 m depth and at spacings of 15 m (FDIR) and 8 m (CDSI). Subirrigation was done by pumping water back into the tiles through the drainage control structures. Overhead irrigation was carried out using a travelling gun. Water table depth, soil water content, drainage outflow, nutrient concentration in drainage water, irrigation rate, weather variables, potato yield and quality parameters, and biomass were measured. Compared to the NDNI treatment, the potato yield increase in the other treatments ranged between 15-32% in 2011 and 2-14% in 2012. In 2011, potato yield from FDIR was higher than CDSI (p = 0.011) and NDNI (p = 0.001), and yield from NDIR was higher than NDNI (p = 0.034). In 2012, potato yield was higher in FDIR in comparison to NDNI (p = 0.021). In 2012, the NDIR gave higher dark ends (p = 0.008) compared to other treatments. Under dry conditions, up to 92% of the potato crop water demand could be met by shallow groundwater contribution. Compared to free drainage, controlled drainage was able to lower the nitrate export by 98% (p = 0.033) in 2010 and by 67% (p = 0.076) in 2011, and the phosphate export decreased by 94% (p = 0.0117) in 2010. A major part of the drainage flow and nutrient export took place between April and June in southern Manitoba. DRAINMOD was able to accurately predict the shallow groundwater hydrology for this particular research site.