No description available.

Cover crops are instrumental in nutrient management and soil health. A field experiment was conducted from fall 2020 to summer 2021 to evaluate the efficiency of different cover crop termination techniques and supplemental nitrogen on sweet corn yield, ear quality and nitrogen use efficiency. The four termination types are herbicide and disk tillage (HDT), herbicide no-till (HNT), cultivation disk till (CDT), and roller crimped no-till (RCNT). These termination types were each divided into four different nitrogen treatment: 0%, 33%, 67% and 100% of the recommended doses (145 kg haˉ¹). Sweet corn yield was highest and % unfilled tip was lowest when cover crops terminated by CDT, followed by RCNT, HNT and HDT. The highest ear weight obtained when 100% of the recommended nitrogen rate was applied to the sweet corn. However, the highest nitrogen use efficiency was obtained when 67% of the recommended nitrogen application rate was used.

Master of Science / Department of Biological and Agricultural Engineering / Philip L. Barnes / The world’s population has passed 7 billion and is expected grow to more alarming numbers by the year 2050. The increase in human life on the planet ushers the need to responsibly and sustainably grow more food. In order to meet the demand necessary, it is crucial that soil remains healthy and crop yields continue to increase in efficiency. Irresponsible or ill-informed practices can lead to depleted resources and degradation of fertile soils that may limit a producers’ ability to sustainably grow food. Cover crops are a tool that can be used to address issues the modern producer may face. Cover crops have been shown to increase cash crop productivity, improve soil health by improving soil physical and chemical properties as well as providing protection from soil erosion runoff or nutrient leaching. A study was conducted in 2014 to examine the short term effects associated with cover cropping systems. The effects of ryegrass, red clover and a cover crop cocktail (mixture of ryegrass, red clover and hairy vetch) compared to bare tilled and bare control plots were studied. The five treatments were replicated three times in a completely randomized study and analyzed. Soil physical health indicators such as bulk density and porosity were calculated. Soil and cover crop nutrient use, as well as, soil moisture content data was collected and analyzed using excel and ANOVA statistical procedures. In the short term, the study found that there was only statistically significant differences between cover cropping regimens, tilled and control plots in regards to biomass production and biomass nutrient concentrations (α=0.05). The cocktail mix provided more biomass, N and P than the ryegrass and clover plots alone. Observable differences in cover crop volumetric soil moisture and water used between plots demonstrated that cover crops utilize soil moisture in the short term, which must be considered in areas experiencing water stress. Although more long-term data is needed to truly quantify how cover crops effect various aspects of soil health, this study demonstrated how cover crops have the potential for providing numerous benefits such as increased erosion control, lower reliance on anthropogenically created nutrients and the reduction of weeds. Overall the benefits associated with cover crops are still being researched and while adoption of cover cropping systems has been slow, a push towards agricultural sustainability while increasing food production will increase the amount of producers utilizing cover crops in the coming years.

Master of Science / Department of Agronomy / Johnathon D. Holman / Kraig L. Roozeboom / Replacing fallow periods with cover crops can provide many benefits including soil quality improvements and reduced nitrogen fertilizer requirements. Field experiments were established near Garden City, KS with winter wheat and fallow phases as main plots, thirteen legume or non-legume cover crops, continuous winter wheat, and fallow as subplots, and cover crop termination method as sub-subplots. Treatments containing triticale had greatest water use efficiency (19.9 kg ha[superscript]-1 mm[superscript]-1) and aboveground biomass (3550 kg ha[superscript]-1), but subsequent winter wheat yields were reduced due to a reduction in volumetric water content. Increased soil residue through greater cover crop biomass resulted in increased precipitation storage efficiency during the fallow period, but water requirements to produce biomass depleted soil moisture more than growing a low biomass crop or fallow. In years of above-average precipitation, low biomass cover crops might be grown with little to no negative effect on subsequent wheat yields. A second field experiment was established near Manhattan, KS with fallow, double crop soybean, and four cover crop treatments planted after wheat harvest in a winter wheat-grain sorghum-soybean no-till cropping system, with five nitrogen treatments applied to the sorghum crop to estimate nitrogen contribution of the cover crops. Greatest above ground biomass production and nitrogen accumulation was observed with sorghum-sudan grass. At the 0 kg ha[superscript]-1 N rate, grain sorghum yields were reduced 1200 kg ha[superscript]-1 following sorghum-sudan grass, while all other cover crop treatments provided a 20-30 kg ha[superscript]-1 N equivalent benefit. Sorghum yields might be reduced following large biomass producing cover crops when nitrogen is limiting, but a small nitrogen benefit might be realized following low C:N ratio cover crops. Cover crop productivity and their subsequent effects on grain sorghum performance were evaluated in field studies established near Manhattan and Hutchinson, KS in 2008 and 2009. Sixteen summer or fall cover crop species were planted in no-tillage winter wheat stubble and evaluated for biomass production, nitrogen concentration, and nitrogen accumulation. Summer annual grass species produced the greatest biomass, 3392 kg ha[superscript]-1 and greater, and legume species accumulated the greatest amounts of nitrogen, averaging 43 kg ha[superscript]-1. Grain sorghum yields were 867 kg ha[superscript]-1 greater following summer cover crops compared to fall cover crops. Cover crops had a significant effect on sorghum performance, with yields 1240 kg ha[superscript]-1 greater following legume cover crops.

4 pp. / Summer cover crops can add nitrogen to the soil, build up and maintain soil organic matter, suppress pest populations, mitigate soil erosion, and reduce nutrient leaching when they are used in Arizona vegetable systems. However, careful management is required since cover crops can modify the availability of soil nitrogen and other critical nutrients. The ratio between carbon to nitrogen (C:N) in decomposing cover crop biomass is a critical indicator of the overall process of breakdown and eventual release of nutrients. This article introduces five cover crops that could improve vegetable systems in Arizona. The mixtures of a legume and a non-legume cover crop species can also be planted to obtain desired C:N ratios to optimize the benefits of cover crops.

Orientador: Luís Roberto Almeida Gabriel Filho / Coorientador: Renato Jaqueto Goes / Coorientadora: Camila Pires Cremasco Gabriel / Resumo: O Sistema Plantio Direto (SPD) tem como característica a ocupação permanente do terreno agrícola com culturas vegetais além da manutenção da palhada sob a superfície do solo. Entretanto, para eficácia do SPD, é necessário adotar culturas de coberturas adequadas com a região a ser implementado, levando-se em consideração fatores edafoclimáticos e tipos de solo, para que dessa forma, haja a formação e manutenção da palhada sobre a superfície do solo. O sorgo possui como principais características, à tolerância de período de seca, e alto volume de produção de matéria seca, importantes para adoção dos sistemas de sucessão de culturas. O milheto, além da alta resistência à períodos de estresse hídrico, possui alta concentração de produção de biomassa. A taxa de decomposição da cobertura vegetal é regulada pela relação Carbono e Nitrogênio (C/N) específico de cada cultura. Nesse contexto, o presente trabalho visou analisar com modelos matemáticos os efeitos do nitrogênio sobre as culturas, sorgo e milheto, com finalidade de posterior uso como coberturas vegetais, sob níveis diferentes de nitrogênio em relação às variáveis de produtividade de matéria seca, teor de Nitrogênio (N), Fósforo (P), Potássio (K), Cálcio (Ca), Magnésio (Mg), Enxofre (S) e Molibdênio (Mo) e acúmulo de N, P, K, Ca, Mg, S e Mo com elaboração do modelo fuzzy. Foi realizada a comparação entre os modelos fuzzy (gaussiano e triangular) e de regressão polinomial por meio de testes estatísticos de ajustes de modelos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Direct Planting System (DPS) has as a characteristic the permanent occupation of the agricultural land with plant crops besides the maintenance of the straw under the soil surface. However, for DPS efficacy, it is necessary to adopt adequate cover crops with the region to be implemented, taking into account edaphoclimatic factors and soil types, so that the formation and maintenance of the straw on the soil surface. Sorghum has as main characteristics, to the tolerance of drought period, and high volume of dry matter production, important for the adoption of crop succession systems. Millet, besides the high resistance to periods of water stress, has high concentration of biomass production. The rate of decomposition of the vegetal cover is regulated by the relation Carbon and Nitrogen (C/N) specific of each culture. In this context, the present work aimed to analyze with mathematical models the effects of nitrogen on crops, sorghum and millet, with the purpose of later use as plant cover, under different levels of nitrogen in relation to the variables of dry matter yield content, Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S) and Molybdenum (Mo) and accumulation of N, P, K, Ca, Mg, S and Mo with elaboration of the fuzzy model. The comparison between the fuzzy (gaussian and triangular) and polynomial regression models was carried out by means of statistical tests of model adjustments and determination of the coefficient of determinati... (Complete abstract click electronic access below) / Mestre

Master of Science / Division of Biology / David A. Haukos / The ring-necked pheasant (Phasianus colchicus) is a popular and economically important upland gamebird in Kansas. Population declines have stakeholders seeking methods to manage populations on agricultural lands. Cover crops planted during the breeding period may provide important resources pheasants require for survival and successful reproduction. I evaluated three cover crop mixes; a custom mix, commercial mix, a wildlife mix, and a chemical fallow control in three counties in western Kansas, during 2017 and 2018 to determine their potential as a management practice for increasing pheasant habitat. I tested the relative effects of spring cover crops on female pheasant survival, nest survival, nest-site selection, and mesocarnivore occupancy. Females pheasants (73) were captured via nightlighting during February – April and fitted with 15-g very-high-frequency radio collars and monitored by telemetry. I placed 58 camera traps on field edges and within cover crop treatments from April to September. Vegetation data were collected at nests and random points to assess nest-site selection and weekly random vegetation points were sampled within treatments. I used known fate and nest survival models in the package RMark interface in R to investigate adult and nest survival (R Core Team 2018). Adult breeding season survival was 0.57 (SE < 0.0001, CI = 0.5739 – 0.5740). Percent spring cover crop positively influenced adult survival (AICc wi = 0.450). Nest survival was 0.36 (SE < 0.001, CI = 0.3614 - 0.3614). Daily nest survival followed a pattern of high survival that gradually declined over the breeding season. Resource selection functions suggest female ring-necked pheasants selected vegetation between 5-7 dm at 50% VOR for nest sites (AICc wi = 0.97). Chi-square analyses suggest females selected Conservation Reserve Program (CRP) patches for nest sites more than expected during both years (2017 χ²₄ = 26.49, P < 0.001; 2018 χ²₄ = 9.80, P = 0.04). CRP supported 57% of nests and 56% of successful nests relative to other cover types. All three of the monitored nests in cover crops were depredated. Ring-necked pheasant occupancy was greatest on edges of treatments (ψ = 0.97, SE = 0.081) and influenced by proportion of the Chick Magnet seed mix (AICc wi = 0.68). Mesocarnivore occupancy was greatest on treatment edges with a constant occupancy of 0.99 (SE = 0.47, AICc wi = 0.66). Spring cover crops provide cover and foraging resources when the majority of agricultural practices are fallow. Spring cover crops do not provide sufficient vertical cover for nesting until after peak nesting occurs, especially during cooler than average winter and spring conditions such as 2018. However, there are tangible benefits of spring cover crops to other biological periods, such as adult female survival, and brood resources if placement of cover crops is targeted near quality nest habitat. My results indicates wheat is an ecological trap for nesting due to increased predation and destruction during harvest. Providing quality nest structure will reduce females nesting in wheat. Incorporation of spring cover crops is a beneficial wildlife management tool that can increase ring-necked pheasant habitat on the landscape.

Orientador: Itamar Andrioli / Banca: Renato de Mello Prado / Banca: Marcio Morais / Resumo: O milho é o principal cereal produzido no Brasil e entre os vários fatores que causam a baixa produtividade, o manejo incorreto do nitrogênio se destaca. Objetivou-se com este estudo, avaliar a eficiência das plantas de cobertura em consorciação com milho na produção de fitomassa e fornecimento de N e por objetivos específicos de: i ) verificar o efeito das plantas de cobertura nas propriedades físicas e químicas do solo; ii) verificar o efeito das plantas de cobertura na produtividade do milho; iii) verificar as melhores doses de N dentro da consorciação de plantas de cobertura com o milho. Para tanto, foi realizado um experimento no município de Ituverava-SP, no Sitio Córrego das Pedras, em Latossolo Vermelho distróferrico típico, textura argilosa para o ano agrícola de 2007/2008 e 2008/2009. O delineamento experimental foi o de blocos casualizados com parcelas sub-subdivididas e quatro repetições. As plantas de cobertura utilizadas foram: braquiária, calopogônio e estilosante do campo grande e as doses de N: N0=0; N1=60; N2=120; N3=180 kg de N/ha. Não foram observadas diferenças significativas para a densidade, porosidade, microporosidade e macroporosidade entre plantas de cobertura e profundidade. Não houve diferença significativa para diâmetro médio geométrico e diâmetro médio ponderado. Não foram observados diferença significativa entre plantas de cobertura e doses de N. Foram observadas diferenças significativas de produtividade entre as plantas de cobertura, destacando-se o estilosante do campo grande com maior produtividade, seguido da calopogônio e braquiária safra 2007/08 e estilosante do campo grande, braquiára e calopogônio safra 2008/09. Para dose de N, foi observado aumento de produtividade para ambas as safras, destacando-se a dose N3. Observou-se incremento na produção de um ano para outro / Abstract: Corn is the main cereal produced in Brazil and among the several factors that cause low productivity, it is possible to detach the incorrect management of the nitrogen. This study aimed to evaluate the efficiency of cover crops intercropped with corn on the production of the phytomass and the providing of N and for specific aims of: i) checking the effect of cover crops on physical and chemical properties of the soil; ii) checking the effect of cover crops on the corn productivity; iii) verifying the best N rates for the intercropping of cover crops and corn. For such reason, an experiment was conducted in Ituverava - SP, at Córrego das Pedras Farm, at a typical Red Oxisol, clay texture for the agricultural year of 2007/2008 and 2008/2009. The experimental design was made in randomized blocks with split plots and four replications. The cover crops used were: Brachiaria brizantha, Calopogonium mucunoides Desv and Stylosanthes capitata and S. macrocephala under the rates of N: N0=0; N1=60; N2=120; N3=180 kg of N/ha. It was not possible to notice significant differences for density, porosity, microporosity and macroporosity among the cover crops and depth. There was no significant difference for the geometric mean diameter and for the average diameter. Significant differences were not noticed among the cover crops and N rates. It was possible to notice significant differences on the productivity among the cover crops, highlighting the Stylosanthes as a cover crop with a higher corn yield, followed by Calopogonium mucunoides Desv and Brachiaria brizantha, harvest 2007/08 and Stylosanthes capitata and S. macrocephala, Brachiaria brizantha and Calopogonium mucunoides Desv, harvest 2008/09. Concerning the N rate, it was possible to notice an increase for both harvests, highlighting the N3 rate. It was possible to observe an increase on production from one year to the other / Mestre

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-10-11T20:09:52Z No. of bitstreams: 1 2016 - Liliane de Souza Ferreira.pdf: 1966686 bytes, checksum: eebcf58399ae9c79283075f9e54588e5 (MD5) / Made available in DSpace on 2017-10-11T20:09:52Z (GMT). No. of bitstreams: 1 2016 - Liliane de Souza Ferreira.pdf: 1966686 bytes, checksum: eebcf58399ae9c79283075f9e54588e5 (MD5) Previous issue date: 2016-08-09 / The management of weeds is complex and comprises a major component of the production cost of most cultures. Growing cover crops is one of the forms of management to reduce weeds competing. Agrobiodiversity, including the biota and the surrounding properties, constituting a cultural and natural capital able to provide ecosystem services. In this context, we developed a study to investigate the potential of wild species Crotalaria incana (rattlesnake rattle or Xique-Xique) and Diodia saponariifolia (Poaia the swamp), which occur in a nearby landscape the Atlantic Forest fragments in the River Basin region Guapi-Macacu-RJ, as part of sustainable agro-ecosystems, constituting strategy to reduce the use of herbicides and enhancing local biodiversity. This potential was assessed in C. incana through phenological studies of plant height, crown diameter, number of branches, presence of inflorescence and number of pods along the cycle and at different times, October, January, February and March. Also evaluated in its interaction with the climate and planting dates. It was found that the planting October C. incana had the longest growing season, low seed production. In the planting in February, the performance of C. incana was good in both parameters; while planting in March, C. incana demonstrated lower performance for mass production and seeds. Preliminary assessments of total biomass and macronutrients, indicate the potential of C. incana as a cover crop that needs to be better investigated. As for D. saponariifolia, a creeping species characterized as macrophyte, evaluations were made of soil coverage percentage after its introduction, compared to the most frequently dominant families in the system, Poaceae and Cyperaceae. Subsequently evaluated the seed bank behavior in this same area after being introduced (experimental area), compared to natural area, which was already established spontaneously. We observed a cooling populations of Poaceae and Cyperaceae after the introduction D. saponariifolia. The spontaneous seed bank revealed a reduction in the expression of these families, important competitors in the system. Possible allelopathic effect of D. saponariifolia in suppressing spontaneous, was evaluated by bioassay with the soil of the natural area where D. saponariifolia prevails spontaneously. In this ground sesame seeds were germinated Sesame indicu L. () in 15-cell trays 3 treatments (T1, T2, T3). T1, activated carbon was added to neutralize allelopathic effects harmful to the development of seedlings. T2, do not add anything. In T3 (control) used a soil adjacent area without the presence of individuals D. saponariifolia. There was no significant difference in the development of seedlings in 3 treatments, indicating no evidence of allelopathic effects of D. saponariifolia on Sesame germination. We can infer that the suppression of processes D. saponariifolia are only for "muffling". / O manejo de plantas espont?neas ? complexo e comp?e um dos principais componentes do custo de produ??o da maioria das culturas. O cultivo de plantas de cobertura ? uma das formas de manejo para redu??o das plantas espont?neas competidoras. Neste contexto desenvolveu-se um estudo com objetivo de investigar o potencial das esp?cies espont?neas Crotalaria incana (Xique-Xique) e Diodia Saponariifolia (Poaia do brejo), que ocorrem em uma paisagem pr?xima a fragmentos de Mata Atl?ntica, na regi?o da Bacia do Rio Guapi-Macacu-RJ, como parte integrante de agroecossistemas sustent?veis, constituindo estrat?gia para redu??o do uso de herbicidas e incremento da biodiversidade local. Este potencial foi avaliado em C. incana, atrav?s de estudos fenol?gicos de altura da planta, di?metro de copa, n?mero de ramos, presen?a de infloresc?ncia e n?mero de vagens ao longo do ciclo e em diferentes ?pocas Outubro, Janeiro, Fevereiro e Mar?o). Avaliou-se tamb?m sua intera??o com o clima e ?pocas de plantio. Constatou-se que no plantio de Outubro, C. incana teve o ciclo vegetativo mais longo, com pouca produ??o de sementes. J? no plantio em Fevereiro, o desempenho de C. incana foi bom em ambos par?metros; enquanto no plantio de Mar?o, C. incana demonstrou menor desempenho tanto para produ??o de massa como de sementes. Avalia??es preliminares de macronutrientes totais e biomassa indicam bom potencial de C. incana a ser melhor investigado. Quanto ? D. Saponariifolia, uma esp?cie rasteira caracterizada como macr?fita, foram feitas avalia??es de porcentagem de cobertura do solo ap?s sua introdu??o, comparando com as fam?lias mais frequentemente dominantes no sistema, Poaceae e Cyperaceae. Posteriormente avaliou-se o comportamento do banco de sementes nesta mesma ?rea ap?s ser introduzida (?rea experimental), comparando com ?rea natural onde j? estava estabelecida espont?neamente. Observou-se um arrefecimento das popula??es de Poaceae e Cyperaceae ap?s a introdu??o D. saponariifolia. O banco de sementes de espont?neas revelou uma redu??o na express?o destas fam?lias e de Asteraceae, importantes competidoras no sistema. Poss?vel efeito alelop?tico de D. saponariifolia na supress?o de espont?neas, foi avaliado atrav?s de biosensaio com o solo da ?rea natural, onde D. saponariifolia predomina espontaneamente. Neste solo foram germinadas sementes de Sesamo indicu L. (Gergelim) em bandejas de 15 c?lulas, com 3 tratamentos (T1,T2,T3). Em T1, adicionou-se carv?o ativado, que neutralizaria efeitos alelop?ticos prejudiciais ao desenvolvimento das pl?ntulas. Em T2, n?o se adicionou nada. Em T3 (controle) utilizou-se um solo da ?rea adjacente, sem presen?a de indiv?duos de D. saponariifolia. N?o houve diferen?a significativa no desenvolvimento das pl?ntulas nos 3 tratamentos, indicando n?o haver evid?ncias de efeitos alelop?ticos de D. saponariifolia na germina??o de Gergelim. Podemos inferir que os processos de supress?o de D. saponariifolia sejam apenas por ?abafamento?.

Cover crops have the potential to reduce environmental impacts of corn production. The objective of this study was to quantify differences in nitrogen (N) and phosphorus (P) loading between corn plots with or without a winter rye cover crop (Secale cerale). Four field plots (30 x 46 m) in Chazy, NY with edge-of-field monitoring were used for the study. Two plots were randomly assigned a rye cover crop treatment and planted with a grain drill at a rate of 112 kg ha-1 after corn silage harvest in 2015 and 2016. Continuous water flows were monitored from surface runoff and tile drain hydrologic pathways dur-ing runoff events. Soluble reactive P (SRP), total P (TP), nitrate-N, total N (TN), and to-tal suspended solids (TSS) concentrations were measured and multiplied by runoff vol-umes to estimate nutrient export. Surface runoff from rye plots had lower nutrient loss compared to control plots. Cumulative nitrate-N exports were similar between treatments (15.7 vs. 14.8 kg nitrate-N ha-1 for rye and control, respectively). Cumulative TN exports were numerically higher for control plots compared to rye plots, (18.8 vs. 21.4 kg TN ha-1). Cumulative TP and SRP exports (surface + tile) for rye were 2.2 and 3-fold greater than control plots, (0.51 vs. 1.19 kg TP ha-1 and 0.33 vs. 0.96 kg SRP ha-1). Total P and SRP loads in surface runoff were 3.0-fold greater for control plots compared to rye plots (0.36 vs. 1.12 kg TP ha-1 and 0.32 vs. 0.94 kg SRP ha-1). TSS load in surface runoff was numerically higher for control plots compared to rye (5.7 vs. 20.6 kg ha-1). Cumulative surface runoff was 1.8-fold greater in control plots compared to rye plots (112.6 mm vs. 207.7 mm), while cumulative tile runoff was numerically higher in rye plots compared to control (83.2 mm vs. 66.1mm). Snowmelt events contributed the majority of phosphorus losses (96% of SRP and 92% of TP), emphasizing the need to implement management techniques that reduce P transport risk during the non-growing season. Winter rye re-duced snowmelt TP export by 3-fold compared to the control plots (0.33 kg TP ha-1 and 1.03 kg TP ha-1). The winter rye cover crop planted after corn silage harvest effectively reduced erosion and P transport in surface water runoff compared to corn silage left fal-low after harvest. In addition to significantly reducing P exports, farms have the option of harvesting rye as a forage crop and double cropping with corn. In this way, more total forage is possible for the farm in addition to offering environmental conservation and wa-ter quality benefits.