<p>Few contemporary studies have examined nutrient accumulation and partitioning of modern corn (Zea mays L.) hybrids grown under in-season sulfur (S) and potassium (K) nutrient management. A fertilizer x hybrid field experiment was conducted during the 2020 and 2021 growing seasons in West Lafayette, Indiana to (1) determine the efficacy of in-season fertilizer management as a strategy to increase grain yield among different modern hybrids, (2) determine the extent to which nutrient harvest index (NutHI) relates to other plant traits under intensive agronomic management, and (3) determine whether grain yield and within-plant nutrient dynamics respond to in-season S and K management differently depending on hybrid. The three fertilizer treatments (whole plot) were (1) Control, no S or K applied, (2) Sulfur, 22.4 kg S ha-1 broadcast applied as ammonium thiosulfate (ATS) [12-0-0-26S] immediately after planting, and (3) Sulfur_Potassium, S (from treatment 2) plus 108 kg K ha -1 topdress applied via Aspire™ [0-0- 58(K2O)-0.5B] at the V4 growth stage. The experiment consisted of four modern Pioneer® corn hybrids (subplot) that varied in crop relative maturity (CRM) from 105 to 114 days planted at the same density following fall strip tillage in a continuous corn production environment. Aboveground dry matter accumulation (DM) and plant tissue concentrations of N, P, K, S, and B were measured via whole-plant samples at V6, R1, and R6. Soil K levels were above the critical K level prior to K application but soil S was not reliably determined. </p> <p><br></p> <p>Grain yields following Sulfur and Sulfur_Potassium treatments were similar, averaging 14.6 Mg ha-1 , which represented a 20% increase over the 12.2 Mg ha-1 observed in the Control. Grain yield gains following S application were the result of increased S uptake, first detected at V6, which alleviated S-deficiency and improved the N to S ratio (N:S) within the plant. K application did not affect grain yield. The greatest contrast in grain yield among hybrids corresponded to extremes in CRM, from 12.9 Mg ha-1 in 105_day to 14.5 Mg ha-1 in 114_day. Fertilizer x hybrid interactions were rarely observed among measured variables with the notable exception of HI, which was increased in later maturity hybrids (111_day and 114_day) by Sulfur and Sulfur_Potassium relative to Control, but was unaffected by fertilizer treatments in 105_day and 110_day hybrids. Most phenotypic parameters were positively influenced by Sulfur and Sulfur_Potassium relative to Control, including above-ground dry matter accumulation (DM), nutrient accumulation, dry matter harvest index (HI), nutrient harvest index (NutHI), and 13 grain/stover nutrient concentrations at maturity. Compared to Control, total plant DM was increased following Sulfur and Sulfur_Potassium by an average of 14% at V6, 16% at R1, and 20% at R6. Whole-plant biomass totals were similar between Sulfur and Sulfur_Potassium, averaging 693 kg DM ha-1 at V6, 10909 kg DM ha-1 at R1, and 26170 kg DM ha-1 at R6; however, K application increased the proportion of total DM partitioned to stover rather than grain, which reduced HI from 0.58 under Sulfur to 0.56 under Sulfur_Potassium. </p> <p><br></p> <p>Nutrient accumulation (of N, P, K, S, and B) was influenced by in-season S and K application at all growth stages relative to the Control. Sulfur application increased V6 wholeplant S and K concentrations, but lowered P and B concentrations. Applying in-season K boosted V6 N and P concentrations, but temporarily reduced K uptake by 10%. Due to gains from S and K application in both DM and nutrient concentration at maturity, total nutrient accumulation in Sulfur_Potassium increased by up to 25% in N, 28% in P, 59% in K, 77% in S, and 44% in B. Total plant DM at maturity was reduced by 14% in the low-yielding 105_day hybrid relative to other hybrids at maturity, leading to similar reductions in nutrient accumulation despite relatively high nutrient concentrations. There was little hybrid variation in whole-plant P, S, and B uptake but substantial hybrid variation in N (9%) and K (21%) uptake. Partitioning of N, P, and K between stover and grain at maturity was influenced by the increased grain nutrient concentrations following Sulfur_Potassium relative to Sulfur. Grain nutrient concentrations under Sulfur relative to Sulfur_Potassium increased from 1.19% N to 1.24% for N, from 0.32 to 0.36% for P, and from 0.39 to 0.44% for K. When Sulfur_Potassium increased grain P and K concentrations over Sulfur, grain nutrient content (i.e., removal) also increased even when grain DM was similar, boosting removal from 48 kg P ha-1 to 54 kg P ha-1 , and from 58 kg K ha-1 to 65 kg K ha-1 . In contrast, grain S and B concentrations, at 0.08% S and 3.3 ppm B, as well as grain contents, at 12.4 kg S ha-1 and 0.05 kg B ha-1 , were similar under both Sulfur and Sulfur_Potassium. As previously stated, NutHI increased substantially in response to both S treatments relative to the Control. The NHI in the Control was just 0.57 versus 0.65 under S treatments while the P harvest index (PHI) was 0.71 versus 0.84, S harvest index (SHI) was 0.50 versus 0.57, and B harvest index (BHI) was 0.35 versus 0.39. Hybrid differences in NutHI were relatively small and were related to both DM and nutrient concentrations at maturity. </p> <p><br></p> <p>While further research is necessary to accurately assess nutrient accumulation and partitioning trends as nutrient management strategies continue to evolve, this study demonstrated 14 that in-season S applications can effectively increase grain yield under S-limiting conditions. Inseason K application did not increase grain yield over Sulfur alone (presumably due to adequate soil K); however, added K still enhanced both grain nutrient removal and NutHI. Furthermore, the influence of plant nutrient concentrations at maturity in both grain (positive) and stover (negative), on NutHI was strongest under fertilizer treatments and NutHI was less dependent on grain yield, total DM, or HI trends. Under hybrid treatments, the influence of nutrient concentrations on NutHI was dependent on DM parameters. While grain yield, DM, and HI were likely to have been contributing factors in NutHI determination, stover nutrient concentration was the most consistent factor related to NutHI across fertilizer and hybrid treatments. The observed variation in NutHI might imply there is still potential for improvement of this index beyond HI alone. Although fertilizer and hybrid treatment responses in whole-plant nutrient concentration were strong during the vegetative period, they were less indicative of NutHI than those at maturity. The positive impact of Sulfur_Potassium on grain nutrient concentration, in the absence of a grain yield response, highlighted a potential disparity between achievable levels of grain nutrient concentration and yield. While in-season nutrient applications can substantially increase grain yields, our results show that in-season fertilizer can also affect nutrient accumulation and partitioning, which are key factors to be considered when making nutrient management decisions. </p>

Thesis (M.Sc.(Agric.))(Agricultural Economics)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references.

The major purpose of this study is to make additional information available to the farm manager through the use of decision theory . This will enable him to improve the decision-making process relating to corn production. The goal is to use the resources at his disposal more efficiently and profitably. This study is primarily concerned with factors that influence planting date and corn variety selection. Within the framework of decision theory analysis , prior and posterior probabilities are employed to calculate the losses that may occur to corn crops in the Cache Valley area of Utah because of harmful spring frosts under optional corn varieties. The alternative of replanting is also added to the model. A brief discussion is included regard ing the impact of water shortage on planting date and corn variety selection. A discussion of factors influencing harvesting decisions is included. The "seventy growing degree day" method is employed as a criterion for planting date select ion. The planting dates a r e matched with four different season length Utah hybrid corn varieties to formulate the courses of action available to the farm manager. The states of nature are the degrees of damage that would occur due to various frost intensities. The decision theory approach of this study identifies the short season variety as the optimal corn crop for Cache Valley, unless planting can be done during the first week in May. This study indicates that planting a shorter season vadety than most Cache Valley farmers have been using in the past would be profitable . Replanting after a frost is found to be unprofitable in marginal cases , but necessary in the case of a killing frost of sufficient duration. The problem of a short water supply adds a constraint as to what varieties can be planted where the time required to reach the third stage of growth is most critical in obtaining potential yields . Finally , it was found that the risk of increased precipitation interfering with harvesting operations becomes almost a certainty if attempts to lengthen the season pushes the harvest too far in to October .

Master of Agribusiness / Department of Agricultural Economics / Keith Harris / The organic food industry experienced rapid growth over the past several decades. Typically, the majority of this growth is associated with the produce sector, but as consumers demand organic options for more food products, organic grains, dairy, and animal meat have emerged as viable food alternatives. There is currently a shortage of organic grains, specifically corn, to feed the livestock that provide organic meat and dairy products. This shortage has led to increased imports of organic corn in order to satisfy the domestic demand. Previous research comparing organic corn prices and profitability to conventional corn have shown organic corn production to be at least as profitable as conventional. With the declining value of cash receipts for conventional corn and the potential profitability advantage of organic corn, very few farmers are devoting acreage to organic corn in the U.S. This study seeks to determine potential economic reasons for this discrepancy. This research develops numerous production scenarios for organic corn in order to observe potential break-even yields a farmer could experience. For example, a nine-year low for price per bushel of organic corn was substituted in to actual values for current production to represent a possible break-even yield that could occur. In this study, the elasticity of organic corn is also calculated. The price elasticity of demand for organic corn gives insight as to how sensitive the demand is to a change in price per bushel. The findings in this study are expected to add insight to the reasons why U.S. farm production of organic corn is less than its domestic demand. It is hoped that famers will benefit from the results in this research in order to better understand organic corn production.

Thesis (Ph. D.)--Michigan State University. Dept. of Agricultural Economics, Dept. of Economics, 2006. / Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references (p. 65-68). Also issued in print.

Row patterns affected irrigated corn productivity when grown in the Mid-South region of the United States. Narrow (76 cm) row spacing increased grain yield 8% when compared to traditional wide (96-102 cm) row spacing. Twin rows (20-25 cm spacing) in a wide (96-102 cm) row pattern, produced similar grain yield as a traditional wide single row. At a normal plant density of 79,040 ha-1, traditional wide rows yielded 10.51 Mg ha-1, twin wide rows yielded 10.34 Mg ha-1, and the narrow rows yielded 11.33 Mg ha-1. Growing corn at various plant densities did not affect corn grain yield response to various row patterns. As a comparison the traditional wide rows and twin rows were similar in their yield, and the narrow rows performed better. Corn grain yields for the traditional 96-102 cm wide single rows were 11.20 Mg ha-1, wide 96-102 cm twin rows yielded 11.22 Mg ha-1, and narrow 76 cm rows produced 12.07 Mg ha-1. Row pattern had no effect on corn plant height, photosynthetically active radiation (PAR), leaf area index (LAI), SPAD, stalk diameter, and plant lodging in either study.

Master of Agribusiness / Department of Agricultural Economics / Allen M. Featherstone / Examining the interaction between population and corn yield is important because the challenge of feeding the world is real. Projections show the world population is increasing and expected to reach over 9 billion people by around 2050. Expanding global urbanization drives the need to increase corn yield on current land and needs to occur to meet global population growth. Previous studies on corn yield increases conclude that ear size is limited and increasing corn plants per acre is important to increasing yield potential. This study used Answerplot data to analyze the effect of increasing plant population on corn yield in 2009. There are over 150 Answerplots across the cornbelt. The weather of 2009 proved to be a challenging year in certain regions of the cornbelt. Record rainfall, and below normal temperature had an influence on corn yield. A total of 4,180 observations from Answerplot were used from across the nation to analyze the relationship between corn yield and plant population. Multiple regression models were estimated and found that in 2009, an increase in plant population from 30,000 to 40,000 plants per acre resulted in an 8.5 bushel per acre increase. This result was robust for various econometric models. Economically, the cost per acre for current seed for this increase in population is about $38.87 per acre. At a corn price greater than $4.58 per bushel, increasing plant population would have made economic sense for 2009.

Made available in DSpace on 2017-07-10T17:44:31Z (GMT). No. of bitstreams: 1 Claudio_Marcos_Metzner.pdf: 1253028 bytes, checksum: c662af6172282a4b707bf70ce4a721b4 (MD5) Previous issue date: 2014-12-18 / Data indicate that Brazil imports on average 75% of the nutrients that make up the base of mineral fertilizers. This implies that there is a moderate correlation in prices of mineral fertilizers with the Dollar. Also, it appears that Brazil is the fourth-largest producer of broilers, demonstrating that there is a large volume of waste generation in this activity, which could be used as corn fertilizer and the farmer can sell the bed of avian. Thereby we seek to answer the research questions: How to determine the price of poultry litter from their nutrients? And how to determine which is the best option in economic terms, of fertilization with avian or mineral bed, to the farmer who plans corn? Thus, the aim of this research was to establish benchmarks for pricing support in the aviary as fertilizer bed. The results show that there is a moderate correlation between the prices of poultry litter, corn and the dollar and the selling price of the poultry litter, from its fertilizer value oscillates between US $ 85 and $ 140 to tonne and that from the productivity of organic fertilization x mineral, it was elaborated arate of reference a benchmark, demonstrating that for the organic fertilizer, poultry litter, is the best option for the farmer who plans corn, in financial terms, considering prices and productivity, the market price in the poultry litter should be over 15% of the price of mineral fertilizer, with formulation 8-20-20 / Dados apontam que o Brasil importa em média 75% dos nutrientes que compõem a base dos fertilizantes minerais. Isso implica que há uma correlação moderada dos preços dos adubos minerais com o Dólar. Também, verifica-se que o Brasil situa-se como quarto maior produtor mundial de frangos de corte, demonstrando que existe grande volume de geração de resíduos nesta atividade, que poderia ser aproveitado como adubação do milho e o avicultor pode comercializar a cama de aviário. Desta forma buscou-se responder as perguntas da pesquisa: Como determinar o preço da cama de aviário a partir de seus nutrientes? E como determinar qual é a melhor opção, em termos econômicos, de adubação, com cama de aviário ou mineral, para o agricultor que planta milho? Assim, objetivou-se com esta pesquisa estabelecer índices de referência para apoio na precificação da cama de aviário como fertilizante. Os resultados encontrados demonstram que existe uma correlação moderada entre os preços da cama de aviário, o milho e o dólar e que o preço de venda da cama de aviário, a partir do seu valor fertilizante, oscila entre U$ 85 e U$ 140 a tonelada e que a partir da produtividade da adubação orgânica x mineral, elaborou-se um índice de referência, demonstrando que para que o adubo orgânico, cama de aviário, seja a melhor opção para o agricultor que planta milho, em termos financeiros, considerando preços e produtividades, o preço de mercado da cama de aviário não deve ser superior a 15% do preço do adubo mineral, com formulação 8-20-20

Field studies were conducted during the summers of 2007 and 2008 at the Agricultural Research and Education Complex, Western Kentucky University, Warren County, KY and commercial production fields in Caldwell County, KY, Warrick County IN, and Vanderburgh County, IN. The goals of these studies were to further validate the Duncan grain yield model, the Russell aboveground biomass model, and to study the effect of inconsistent spacing within rows on Zea mays L. yield. Plant spacing other than uniform decreases grain yield and profitability. The population experiments conducted at the Warren County location were a randomized complete block design with three planting densities, three varieties (c.v. DeKalb DKC6547, DeKalb DKC6346, DeKalb DKC6478) in 2007 and (DeKalb DKC6478, DeKalb DKC6342, and DeKalb DKC6544) in 2008, and three replications. Seeds were planted in rows 76 cm apart and 9.1 m long with four rows per plot in a no-till system on a Crider Silt Loam with pH of 6.8 and 1.5% organic matter. The effect of variable within row spacing was evaluated in commercial production fields by randomly selecting five adjacent rows of 5.3 meters in length at each location. Grain yield for each row was then curve fitted both linearly and exponentially. Minimizing interspecies competition was essential to evaluating the effects of competition within Zea mays L. A burn-down application of 2,4-D and glyphosate was used prior to planting. The most common weeds in the plots were Sorghum halepense L. (johnsongrass), Trifolium repens L. (white clover), and Taraxacum officinale L. (common dandelion) . Glyphosate was reapplied throughout the growing season due to reemergence of S. halepense and Ipomoea hederacea Jacq. (ivyleaf morningglory). The weight of each ear was recorded and one row from each plot was randomly selected to shell. The moisture content was measured from a subsample twice each row using an electrical conductivity moisture meter. The mean of the two moisture readings was used as the moisture content from the plot. Cob weights from shelled ears were recorded to determine the grain/cob mass ratio. This ratio was used to project the grain weight for the remaining harvested rows. Duncan’s grain yield model and Russell’s biomass model were curve fitted to the data for areas of 0.00040 hectares at the p < 0.05 significance level or greater in all population density plots. Individual plant grain masses were curve fitted to Duncan’s model with p < 0.05 significance in 3 out of 15 plots. Grain mass was negatively correlated (R < 0) with standard deviation of within row spacing in 14 of 15 plots. A linear fit to this trend was significant in only 2 of 15 plots. The Duncan yield curve and the Russell aboveground biomass model fit all 6 genotype by environment interactions for 2007 and 2008 to the α = 0.05 level of confidence when evaluated over a 5.3 meter length on 76.2 cm wide rows. Individual plants fit linearly at α = 0.05 in 9 out of 15 plots. Individual plants fit the Duncan yield curve at α = 0.05 in 4 out of 15 plots. Standard deviation of within row spacing fit grain yield loss significantly at &#; = 0.05 in two of 15 plots. The individual plant spacing and local population density collectively fit nine plots significantly at α = 0.05 or better.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-21T13:47:37Z No. of bitstreams: 1 Helio Gomes Arcanjo Junior.pdf: 943075 bytes, checksum: a2b879ed967c57e40067c04cd29fde6a (MD5) / Made available in DSpace on 2017-02-21T13:47:37Z (GMT). No. of bitstreams: 1 Helio Gomes Arcanjo Junior.pdf: 943075 bytes, checksum: a2b879ed967c57e40067c04cd29fde6a (MD5) Previous issue date: 2014-02-24 / Corn [Zea mays (L.) Poaceae] is one of the most widely produced crops in the world, with high nutritional value and diverse applications, serving as a food source for both humans and animals. The production of mini-corn increases the yield and accelerates the return of the producer’s investment. The cultivation of mini-corn generates waste from other parts of the plants, such as the stem and leaves, which are often discarded and serve as green fertilizer for the next crop. However, these parts of the mini-corn plant may serve as food for ruminants. It is therefore necessary to evaluate the remains of mini-corn plants after the harvesting of the corn. The aim of the present study was to evaluate the bromatological characteristics and in vitro digestibility of corn plants after the harvest of five varieties of mini-corn. A randomized, block design was used with a 5 X 2 factor scheme in subdivided plots with five varieties (AG 1051, Alagoano, Branquinha, São Luíz and Viçosence) with and without the harvesting of cobs in a subplot with three blocks. The Alagoano and Viçosence varieties had the highest crude protein content in the subplot without cobs. The AG1051, Branquinha and Viçosence varieties had the highest total digestible nutrients in the subplot without cobs (P > 0.05) and demonstrated the greatest fodder potential among the varieties tested. The Alagoano variety had the highest neutral detergent fiber and in vitro digestibility of neutral detergent fiber in the subplot without cobs (P > 0.05). / O milho [Zea mays (L.) Poaceae] é uma das culturas mais produzidas no mundo, possuindo alto valor nutritivo e diversas aplicações, servindo tanto na alimentação humana quanto para a alimentação animal. A produção do minimilho aumenta a rentabilidade e a velocidade do retorno do investimento ao produtor. Entretanto o cultivo do minimilho gera resíduos, tais como a planta de milho composta por palha (caule e folha) onde muitas vezes esta é desprezada servindo de adubo verde para a próxima cultura. No entanto a palha do minimilho pode servir de alimento para os ruminantes, portanto, faz-se necessário à avaliação das plantas remanescentes a colheita do minimilho. Objetivou-se neste trabalho avaliar as características químicas bromatológica e a digestibilidade in vitro de plantas integras de milho e de plantas remanescentes a colheita de minimilho de cinco variedades de milho. O delineamento foi em blocos casualizados em esquema fatorial 5x2 em parcelas sub divididas sendo, cinco cultivares na parcela (AG 1051, Alagoano, Branquinha, São Luíz e Viçosence) e com e sem colheita do minimilho na sub parcela com três blocos Dentre as variedades selecionadas as que obtiveram maiores valores para PB na sub parcela sem espiga foram as cultivares Alagoano e Viçosence. Para a variável NDT na sub parcela sem espiga as variedades que obtiveram valores superiores (P<0,05) foram o AG1051, a Branquinha e o Viçosence obtendo estes, maior potencial forrageiro diante as outras cultivares. Nas variáveis de FDN e DIVFDN na sub parcela sem espiga a variedade que obteve maiores valores (P>0,05) foi o Alagoano.