<p>In previous research in continuous corn with no-till management, starter fertilizer consistently increased vegetative plant development rate and plant dry matter prior to sidedressing and decreased grain moisture. However, increased yield did not always occur. The objective of my study was to evaluate the effects of starter fertilizer on plant dry matter and nutrient content throughout the growing season to determine if differences in these parameters determined early in the growing season persisted throughout reproductive growth and explained yield effects. Experiments were conducted in long-term continuous corn no-tillage fields at SEPAC, NEPAC, and TPAC in 2019 and 2020. At TPAC, treatments were control and starter, 46 kg N ha^-1 and 18 kg P ha^-1. At SEPAC and NEPAC, we also evaluated starter fertilizer composition, and the treatments were control, 3.6 kg N ha^-1 and 8 kg S ha^-1; N, 34 kg N ha^-1 and 8 kg S ha^-1; NP, N plus 7.5 kg P ha^-1; and NPK, NP plus 9.5 kg K ha^-1. Starter fertilizer was applied 5 cm below and 5 cm to one side of the seed. Total N rate was equalized by adjusting the N application at sidedressing to compensate for the N applied in starter.</p> <p>Although starter fertilizer treatment effects differed from those of the control, in most cases starter fertilizer effects were the same regardless of composition. Hereafter, ‘starter fertilizer’ will refer to the mean of the three starter fertilizer treatments, N, NP, and NPK for SEPAC and NEPAC or NP in the case of TPAC. Crop growth rate determined by the number of collared leaves was increased by starter fertilizer, compared to the control, at all site-years. Starter fertilizer increased leaf appearance up to one leaf in plots evaluated at the same point in time and final leaf number was also one more leaf per plant. Starter fertilizer increased dry matter as early as V4 compared to the control at SEPAC and TPAC, with differences maximizing around V6-V12. Effects at NEPAC were inconsistent throughout the season. At reproductive stages the magnitude of the differences in dry matter decreased until starter fertilizer and control treatments had similar dry matter at maturity. Before sidedressing, N and P concentrations were greater with starter fertilizer than the control, but after sidedressing concentration of these nutrients were greater with control than starter fertilizer. The differences in N and P concentration between starter treatments and the control increased in later vegetative stages, but decreased during reproductive stages and at maturity. Potassium concentration was generally unaffected by the fertilizer treatments. Plant nutrient content differences between starter fertilizer treatments and the control were similar to differences seen with dry matter, despite the differences in nutrient concentration between starter fertilizer and the control. When compared at the same growth stage, starter fertilizer treatments and the control, had similar DM and nutrient concentration and content. Starter fertilizer, compared to the control, resulted in earlier silking and/or tasseling at all site-years. Starter fertilizer accelerated vegetative crop development, but this did not result in substantial differences in dry matter or nutrient content at similar growth stages, including physiological maturity. Despite this result, increased grain yield with starter fertilizer, compared to the control, occurred at 3 of 6 site-years and ranged from 300 to 1000 kg ha^‑1. Grain moisture was decreased by starter fertilizer at 4 of 6 site-years by at least 5 g kg^-1.</p>

Conservation tillage production systems for flue-cured tobacco (Nicotiana tabacum L.) have been studied for many years. Inadequate chemical weed control and lack of acceptable pesticide and fertilizer application resulted in consistently lower yields and inferior cured leaf quality. The development of new conservation tillage equipment, improved methods of fertilizer application, and new herbicides, have resulted in a renewed interest in conservation tillage labeled for tobacco. This research investigated management practices to address slow early season growth characteristic of strip-tillage tobacco production. Objectives of the first study were to evaluate the methods of starter fertilizer application and determine the optimal rate. A transplant water treatment (11 kg ha⁻¹) and 3 rates (11, 22, and 45 kg ha⁻¹) of injected 9-45-15 (N:P₂O₅:K₂O) water soluble starter fertilizer were evaluated for early season plant growth and time of topping. Starter fertilizer treatments increased tobacco root weight by 22% and leaf area up to 41%. Earlier topping was observed as a result of starter fertilizer with 23 and 6% more plants topped during the initial topping date in 1999 and 2000, respectively. Starter fertilizer did not consistently increase the yield of either strip-tillage or conventional tillage tobacco. The objectives of the second study were to compare the use of raised beds with flat-planting and investigate cover crop residue management techniques. Residue management treatments minimized residue within the strip-tilled area with an early hooded spray application (strip-killed) of a burndown herbicide as opposed to the traditional broadcast burndown application. The use of raised beds for strip-tillage production of tobacco showed no clear benefit when compared to flat-planting. Strip-tillage plots were similar to conventional tillage for cured leaf quality and yield. Early season strip-kill burndown herbicide applications proved beneficial in reducing difficulties incorporating residue into the strip-tilled area thus improving the quality of the prepared seed bed. This research has added to the present knowledge regarding strip-tillage tobacco production, and refined necessary cultural practices. Transplant starter fertilizer is recommended to overcome the typical slow early season growth characteristic of strip-tilled tobacco. However, increased rates (greater than 11 kg ha⁻¹) or under-row injection of the material had no added benefit. The research also demonstrated that the use of raised beds should not be considered a necessary practice with the use of a strip-till implement that incorporates under-row subsoil tillage. This research has demonstrated that tobacco yields and quality comparable to conventional tillage can be realized using strip-tillage production techniques. / Master of Science

AN ABSTRACT OF THE THESIS OF JESSE MILLER, for the Master of Science degree in PLANT, SOIL, and AGRICULTURAL SYSTEMS, presented on May 13, 2016 at Southern Illinois University Carbondale. TITLE: THE EFFECTS OF STARTER FERTILIZER ON SOYBEAN INFESTED WITH FUSARIUM VIRULIFORME OR RHIZOCTONIA SOLANI MAJOR PROFESSOR: Dr. Jason Bond Fusarium virguliforme (Aoki), the fungus that causes sudden death syndrome of soybeans (SDS), is prevalent in most of the soybean (Glycine max L. Merr.) production regions throughout the United States. Sudden death syndrome management has been limited to cultural practices and host resistance. Rhizoctonia solani (Kühn) is a fungus responsible for pre-emergence and post emergence damping off. Control methods include seed treatments and cultural practices. Several companies have advocated the use of in-furrow starter fertilizers in soybean production. Promoting root growth and emergence are a couple of the alleged benefits. It is unknown if the increased fertility in the root zone may actually increase or decrease the severity of root or seedling diseases. An objective of this study is to determine if the starter fertilizers (2-6-16), (7-12-11), (3-10-13) Nachurs Alpine Solutions™ impacts seedling disease caused by Rhizoctonia solani and soybean yield. A second objective is to determine if starter-fertilizer influences the incidence and severity of SDS and soybean yield. One trial was infested with R. solani at the rate of 0.9 g of inoculum/30.5 centimeters of row. A second trial was infested with F. virguliforme at the rate of 2.25 g/30.5 centimeters of row. Inoculum consisted of sterilized white sorghum inoculated with either pathogen. Plots were 3.04 meters wide by 6.1 meters in length with row spacing of 0.76 meters. Trials took place during the growing season of 2014 and 2015. In 2014, a randomized complete block design consisted of 4 treatments that were replicated 6 times and planted into 4 row plots. Treatments consisted of treated (Metalaxl™, Fluxapyroxad™, Pyraclostrobin™, and Imidacloprid™) or non-treated seed (‘Asgrow 4730’) combined with either fertilizer (2-6-16) or non-fertilizer. Across both trials, there were no seed treatment and fertilizer rate interactions. In the R. solani trial, stand counts were similar between the fertilizer and non-fertilizer treatments. Stand counts were higher when the seed treatment was used. There was no significant difference in soybean yield regardless of treatment. In the F. virguliforme trial, stand counts were reduced in the fertilizer treatment when compared to the non-fertilizer treatment. Foliar symptoms of SDS and soybean yield were not affected by treatment. In 2015, there were changes in treatment structure due to additions of fertilizer treatments 7-12-11 and 3-10-13. Seed treatments and randomized complete block design remained for 2015. Stand counts were higher in plots that received fertilizer treatments in the R. solani trial. Stand counts were lower in R. solani plots with treated seed. Yield was not influenced by seed treatment but was increased by 3-10-13 and 7-12-11 fertilizer treatments. For the F. virguliforme trial, reduced stand counts were found in the plots with seed treatments. Seed treatments did not influence yield. Fertilizer did not impact stand or yield. Foliar symptoms of SDS were not influenced by seed treatment or fertilizer.

<p>Starter fertilizer applied with or near the seed at planting often enhances early season maize growth (<i>Zea mays</i> L.) but does not always result in higher grain yield. Other responses to starter fertilizer, such as reduced thermal time to reach silking, which suggests accelerated plant development, have been documented. The objective of this study was to examine the relationship between dry matter production and accelerated plant development with respect to 5x5 cm starter (ST) and in-furrow popup (PU) fertilizer. A field experiment was conducted in 2016 with three at-planting treatments consisting of one single rate and formulation of ST (53 N and 21 P kg ha^-1) or PU (4 N and 6 P kg ha^-1), and an untreated control. In 2018, the study included four additional site-years with treatments consisting of an intermediate (ST) or high (STH) starter fertilizer rate, and an untreated control. For ST treatments, depending on location, nitrogen (N) and phosphorus (P) fertilizer rates ranged between 26-28 and 6-10 kg ha^-1, respectively, and for STH treatments N and P fertilizer rates ranged between 47-56 and 12-20 kg ha^-1, respectively. In 2016, as new leaf collars appeared, dry matter increased exponentially, but at an equal number of leaf collars ST and PU had similar dry matter as the control. In 2018, dry matter for ST, STH, and control was also similar when normalized for leaf collar number at each site. Overall, these results suggest that enhanced dry matter at a given point in time from ST, STH, or PU was a function of accelerated leaf development as opposed to physically more robust plants of the same leaf collar number. Grain yield was unaffected by ST, STH, or PU treatments at any site-year.</p> <p>Methods used to study roots in crop fields have included extracting soil cores, excavating entire root systems, using radioactive and non-radioactive chemical tracers, or using mini-rhizotrons. However, due to the intensive nature, level of difficulty, and cost associated with these methods, their use in crop fields has been minimal. We developed an alternative method to quantify maize rooting density over time. The method involved perforated cylinders installed vertically into the soil at different distances from the row, which made roots growing into the cylinder voids visible from the soil surface and possible to count [root number density (RND)] at different depths using a video recording device (1m-long borescope). The objective of this study was to determine if the cylinder method could quantify rooting density throughout the growing season (V3, ~V7, and R2-R3) similar to the more intensive soil core method, compared in two starter fertilizer trials [continuous maize (M/M) and maize/soybean (M/S) rotation]. Cylinders were constructed with perforated (49% voids) polypropylene resin to an inside diameter of 2.58 cm and a length of 30 cm. Cylinders were painted with red and green alternating markings (5 cm) on the outside and inside walls to visually aid in identifying depth from the soil surface. After plants emerged, cylinders were inserted vertically into the soil after drilling a 3.5 cm diameter borehole. Ten perforated cylinders were installed in a parallel line 13 or 25 cm away from, and on both sides of, the planted row. Soil cores were also collected at the same relative locations for conducting root extractions and subsequent calculation of length density (RLD). At V3, methods frequently resulted in the same significant (<i>p≤</i>0.10) or insignificant (<i>p></i>0.10) main and interaction effects in both fields, whereas at ~V7 and R2-R3, there were several instances where the cylinder method failed to detect the same effects as the soil core method. At times both the cylinder method and the soil core method detected significant main or interaction effects, but the direction of the effect was opposite.</p> <p>In-furrow biological (BIO) and plant growth regulator (PGR) products, otherwise known as biostimulants, are becoming increasingly available in the commercial maize market. The objective of this study was to compare the effects of several commercially available in-furrow biostimulant products on maize growth and development, nutrient uptake, and grain yield to starter fertilizer in large-plot field trials. The study was conducted across five locations in 2016, and three locations each in 2017 and 2018 at Purdue University research farms. At each location, treatments consisted of four different BIO or PGR products plus starter fertilizer, starter fertilizer only, and an untreated control. Compared to the control, starter-only increased grain yield at 7 of 8 site-years in 2016 and 2018 ranging from 125 to 753 kg ha^-1, depending on location, but no increase was found at any of the 3 locations in 2017. Grain yield was increased (3 of 11 site-years) or decreased (2 of 11 site-years) by some of the BIO or PGR products, but in 6 of 11 site-years none of the products affected yield compared to starter-only.</p>

Doctor of Philosophy / Department of Agronomy / Dorivar Ruiz Diaz / Winter annual weeds (WAW) could affect nitrogen supply for corn production. The objectives of first study were to determine the diversity and abundance of WAW and to evaluate the effect of delaying herbicide applications on nitrogen supply and no-till corn response. Research was conducted in 2010 and 2011 at 14 sites in eastern Kansas. A factorial arrangement of three herbicide application dates (Nov.-Mar., April, and May) and five N rates were used. The three most abundant WAW across sites were henbit, purslane speedwell, and horseweed. Delaying herbicide application until April significantly reduced early corn N uptake by 52 mg N plant-1, chlorophyll meter readings at silking by 3.4%, and grain yield by 0.48 Mg ha-1 across sites. An additional 16 to 17 kg N ha-1 was needed to maintain yield if herbicide application was delayed until April. Starter and foliar micronutrient fertilization can potentially increase corn and soybean yield. The objectives of the second study were to evaluate crop response from combinations of starter and foliar fertilizers that contain N-P-K mixtures with and without a blend of micronutrients at four sites for each crop under irrigated conditions. No early corn growth or yield increase was attributed to application of micronutrients (Fe, Mn, Zn, Cu, and B) beyond what was achieved with N-P-K starter fertilization. There was an increase in soybean height (8 cm) and yield (293 kg ha-1) with starter fertilizer containing N-P-K plus micronutrients over the control. No increase in corn or soybean yield was obtained with foliar fertilization. The objective of the third study was to compare soil mobility and changes in soybean nutrient concentration in the leaf and seed from Mn and Zn sources (EDTA and oxysulfate) at two sites. Zinc sources were more mobile in the soil. Both Zn sources increased seed Zn concentration. Manganese oxysulfate increased seed Mn concentration. However, soybean trifoliolate leaf and seed Mn concentration decreased with soil-applied Na2EDTA and MnEDTA. This response was attributed to formation of FeEDTA and increased Fe supply that reduced root Mn absorption. Manganese EDTA is not recommended for soil application.

No description available.

Maize is the dominant crop in northwestern Germany and is mostly cultivated on sandy soils. Additionally, due to intensive livestock husbandry and biogas production, large amounts of liquid manures are produced. The current farm practice leads to high N and P surpluses at field level accompanied by environmental pollution, like nitrate leaching, eutrophication of non-agricultural ecosystems, and N2O emissions. The accruing liquid manures are often used for maize fertilization. Thereby, slurries are mainly broadcast applied using trailing hose applicators followed by incorporation into the topsoil. In addition, a mineral N P starter fertilizer (MSF) is band-applied below the seed-corn at planting to overcome the limited nutrient availability during the early growth stages. Using a slurry injection technique below the maize row before planting might serve a substitute for MSF. Addition of a nitrification inhibitor (NI) into the slurry before injection seems to be an option to further decrease N losses. The objectives of this thesis were to compare the current and novel fertilizing strategies with a special focus on soil mineral nitrogen (SMN) dynamics and plant P, zinc (Zn) and manganese (Mn) status. For both issues the effect of adding a NI into the slurry was investigated. To characterize the SMN dynamics after slurry injection an appropriate soil sampling strategy had to be developed. Therefore, three consecutive field trials were conducted. The first testing of the new soil sampling approach was implemented in an existing experiment where the slurry was injected at a depth of 12 cm (upper rim) below the soil surface. The soil profile (75 cm wide) centered below the maize row was sampled using a grid-like approach to a depth of 90 cm. Around the injection zone, soil monoliths (SM) were sampled using a purpose-built soil shovel. Below the SMs and in the interrow space (15 and 30 cm distance to the row) a standardized auger procedure was used. The second experiment aimed to improve the sampling strategy with focus on sample homogenization quality and necessary sample sizes per pooled sample. In the third experiment this improved sampling strategy was validated. Results from the first testing of the sampling procedure showed that the strategy is suitable, although some problems occurred. Especially the high spread in values among the replications caused high coefficients of variation (CV; mostly 40 – 60%). The improvement trial revealed that for the SM, which contains the slurry band, an intensive homogenization is required. In addition, suitable sample sizes (twelve auger samples and six soil monolith samples per pooled sample) have to be collected to obtain reliable SMN values. Following this enhanced sampling strategy in the final validation trial, the spread in values was considerably reduced and resulted in CV values of mostly < 20%. The method can be adapted to other fertilizer placement strategies and further row crops. To compare both fertilizing strategies with respect to the spatial and temporal SMN dynamics as well as to the plant nutrient status two field trials were conducted using pig slurry on sandy soils in 2014 and 2015. Four treatments were tested: unfertilized control, broadcast application + MSF, injection, and injection + NI. Soil samples were taken using the new sampling strategy at several dates during the growing season. Plant samples were simultaneously collected to evaluate the plant P, Zn, and Mn status at different growth stages. In 2014, all fertilized N was displaced from the top soil layer of the broadcast treatment until the 6-leaf stage due to heavy rainfall, while N displacement was significantly smaller after slurry injection. The lateral movement of injected slurry N was negligible. In 2015, almost no displacement of fertilized N out of the top soil layer occurred independently of treatments, due to distinctly lower rainfall. The release of slurry N was delayed following broadcast application and large SMN concentrations were detected in the injection zones until the 10-leaf stage. The addition of a NI resulted in significantly increased NH4-N shares in the injection zone throughout the early growth stages (+ 46% in 2014 and + 12% in 2015 at 6-leaf stage). Thus, in 2014 SMN displacement was delayed, and in 2015 increased SMN concentrations were found around the slurry band, most probably due to lower N losses via denitrification. Furthermore, NI addition significantly increased the nutrient uptake by maize during early growth in both years. With P deficiency due to cold weather conditions in 2015, broadcast application showed higher P uptake until the 6-leaf stage (36 – 58%), while it was lower at the 8- (32%) and 10- (19%) leaf stages compared to slurry injection (+ NI). Zn availability was enhanced during early growth after slurry injection (+ NI) and Zn as well as Mn uptake were higher at harvest. Furthermore, dry matter yields were higher (2014) or equal (2015) compared to broadcast application. The P balances were decreased by 10 – 14 kg P ha-1, while Zn and Mn balances were excessive independent of treatments. The field trials showed that after slurry injection, especially when combined with a NI, the applied nitrogen is located in a soil zone with better spatial availability for plant roots compared to broadcast application. Furthermore, the MSF can be substituted without affecting early growth of maize. In conclusion, slurry injection leads to equal (or even higher) yields and enables farmers in northwestern Germany to reduce the P and N surpluses. This would support several goals concerning sustainable land use: Lower pollution of ground and surface waters, reduced emission of NH3, more efficient use of the limited rock P reserves, and less need of transporting organic manures out of regions with intensive animal husbandry and/or biogas production. However, slurry injection enhances the risk of N2O emissions, which contributes to climate change. Thus, for a final evaluation of the environmental impact a life cycle assessment would be worthwhile.

A review of available corn relative maturity groups in Mississippi shows a limited range of maturity groups in use. Research focusing on expanding the range of maturity groups was conducted in MS in 2015 and 2016. Along with expanded maturity groups, treatments of fertilizer (10-34-0), foliar zinc, and a plant hormone blend were studied to shorten the growing season. Four site years in MS were studied to determine optimal plant maturity group and treatment for length of season. The results showed decreased yield of 0.09-0.15 Mg ha-1 (1.5-2.3 bu ac-1) for each day of decreasing relative maturity in three of four site years. The addition of starter fertilizer increased vegetative growth stage, plant height V5 and V7, SPAD values at V5, and significantly decreases days to tassel and silking reproductive growth stages but did not affect yield.