Foliar Application of Phosphorus on Winter Wheat Grain Yield, and Use of In-season Reflectance for Predicting Yield Potential in Bermudagrass

Soil Scienc

Effect of Nitrogen Fertilization and Liming on Rye-Ryegrass Yield and Soil pH Dynamics

Using ammonium based nitrogen fertilizers in crop production has been shown to acidify soils. Lime used to correct soil pH is an important cost to producers. Recommendations of the optimal level of nitrogen to apply typically ignore the cost of lime created by nitrogen fertilization. This study was aimed to estimate soil pH change in response to nitrogen and lime application, and determine the effect of considering the cost of lime on recommendations about the optimal level of nitrogen. Yield response and pH functions were estimated and used to determine optimal levels of inputs. The effect of the cost of lime on recommendations about the optimal level of nitrogen was found to be marginal. Nitrogen acidification was found to be more severe with nitrogen application amounts above recommended rates than with nitrogen that is used by the plant.Lime, Nitrogen, Soil pH, Rye-ryegrass, Crop Production/Industries, Production Economics,

Determining Optimal Levels of Nitrogen Fertilizer Using Random Parameter Models

The parameters of yield response functions can vary by year. Past studies usually assume yield functions are nstochastic ‘‘limited’’ stochastic. In this study, we estimate rye– ryegrass yield functions in which all parameters are random. The three functional forms considered are the linear response plateau, the quadratic, and the Spillman-Mitscherlich. Nonstochastic yield models are rejected in favor of stochastic parameter models. Quadratic functional forms fit the data poorly. Optimal nitrogen application recommendations are calculated for the linear response plateau and Spillman-Mitscherlich. The stochastic models lead to smaller recommended levels of nitrogen, but the economic benefits of using fully stochastic crop yield functions are small because expected profit functions are relatively flat for the stochastic yield functions. Stochastic crop yield functions provide a way of incorporating production, uncertainty into input decisions.cereal rye–ryegrass, Monte Carlo, nitrogen, random parameters, stochastic plateau, Production Economics, Q10, C12, D24,

Determining Optimal Levels of Nitrogen Fertilizer Using Random Parameter Models

The parameters of yield response functions can vary by year. Past studies usually assume yield functions are nonstochastic or ‘limited’ stochastic. In this study, we estimate rye-ryegrass yield functions where all parameters are random. Optimal nitrogen rates are calculated for two yield response functions: linear response plateau and quadratic. Nonstochastic models are rejected in favor of stochastic parameter models. However, the economic benefits of using fully stochastic models are small since optimal nitrogen rates do not differ greatly between stochastic and nonstochastic models.Linear response plateau, Monte Carlo, nitrogen, random parameters, Agricultural and Food Policy, Crop Production/Industries, Farm Management, Production Economics,

The Values of Warm-Season Native Perennial Grasses Grown for Pasture or Biofuel in the Southern Great Plains, USA

The Renewable Fuel Standard under the Energy Independence and Security Act of 2007 mandated the production of 136 billion liters of cellulosic biofuel by 2022. Switchgrass (Panicum virgatum) has been identified as a primary feedstock because it is a perennial, produces high yields and is adapted to a wide environmental range. Development of the cellulosic biofuel industry has been slow. A reason for this slow development is lack of available feedstock driven by lack of a developed market. Rather than considering switchgrass only as a dedicated biofuel feedstock, we examined its potential both for grazing and biofuel feedstock. In a series of experiments testing yield, grazing preference and animal gain; switchgrass (cv. Alamo) was found to produce greater total yield (17696 kg/ha) than fifteen other warm season perennial grasses, was the most preferred by stocker cattle in a grazing preference study and produced average daily gains in a grazing study (0.84-1.05 kg/hd). These results demonstrate the potential of switchgrass for both grazing and biofuel feedstock. However, the feedstock price would need to increase above $91/t before the economics of dedicated switchgrass feedstock production would surpass that of a combination of switchgrass grazing and feedstock production

Plant and Endophyte Effect on Fiber, N, and P Concentrations in Tall Fescue

Tall fescue (Lolium arundinaceum) infected with an endophyte (Neotyphodium spp.) generally has agronomic advantages over endophyte-free tall fescue. The objective of this study was to determine if endophyte presence (E+) or absence (E−) in three tall fescue genotypes affects concentrations of acid detergent fiber (ADF), neutral detergent fiber (NDF), nitrogen (N), and phosphorus (P) in field and greenhouse studies. E+ plants had higher concentrations of ADF and NDF (nonsignificant in one genotype) in the field study. Endophyte lowered N concentration in the field from 19.2 to 18.5 g kg −1 . Various interactions between genotype, endophyte, and maturity were significant for NDF, N, and P in both field and greenhouse studies. This interaction occurred because the effect of the endophyte increased or decreased fiber, N, and P content of tall fescue depending upon plant genotype. This genotype by endophyte interaction should be kept in mind as novel endophytes are selected and placed into tall fescue cultivar selections, this interaction could alter fiber, N and P accumulation of the plants which depending upon plant genotype could result in a positive or negative response

Plant and Endophyte Effect on Fiber, N, and P Concentrations in Tall Fescue

Tall fescue (Lolium arundinaceum) infected with an endophyte (Neotyphodium spp.) generally has agronomic advantages over endophyte-free tall fescue. The objective of this study was to determine if endophyte presence (E+) or absence (E−) in three tall fescue genotypes affects concentrations of acid detergent fiber (ADF), neutral detergent fiber (NDF), nitrogen (N), and phosphorus (P) in field and greenhouse studies. E+ plants had higher concentrations of ADF and NDF (nonsignificant in one genotype) in the field study. Endophyte lowered N concentration in the field from 19.2 to 18.5 g kg−1. Various interactions between genotype, endophyte, and maturity were significant for NDF, N, and P in both field and greenhouse studies. This interaction occurred because the effect of the endophyte increased or decreased fiber, N, and P content of tall fescue depending upon plant genotype. This genotype by endophyte interaction should be kept in mind as novel endophytes are selected and placed into tall fescue cultivar selections, this interaction could alter fiber, N and P accumulation of the plants which depending upon plant genotype could result in a positive or negative response

Forage Yields from 2008-2009 Ryegrass

Introduction Livestock and forage production are the largest contributors to agricultural income in the primary service region of the Noble Foundation. The ryegrass (Lolium multiflorum L) variety testing program is designed to provide up-to-date performance information to cooperators and producers in Oklahoma and Texas about ryegrass varieties that are commercially and commonly available. In addition, the program provides a tool to evaluate and compare experimental breeding lines emerging from the Noble Foundation breeding program as well as other public and private breeding programs. The program is intended to furnish producers with supplemental information, aid decision-making and idea formation. The information coming from the variety testing program should be a valuable tool when used with similar information from other sources. The objective of this report is to summarize forage yields from the 2008-2009 ryegrass variety trial. Materials and Methods The annual ryegrass variety trial was conducted on a Wilson silt loam soil at the Noble Foundation Headquarters Farm, Ardmore, Okla. The experimental design was a randomized complete block with three replications. The experimental unit was a 5- by 10-foot plot of a single variety. The trial consisted of 28 entries that were evaluated during the 2008-2009 crop growing season. Twelve sources contributed entries to the trial (Table 1). The entries were seeded into a clean-tilled seedbed on Sept. 24, 2008. Each entry was drilled in 5- by 10-foot plots, in 7-inch rows, with 25 lbs/ac (pure live seed) at a ½-inch planting depth with a HEGE 500 drill. Fertilization consisted of preplant incorporation of 120 lbs N/ac and 30 lbs P205/ac, 60 lbs K2O/ ac during September 2008, and a topdress application of 80 lbs N/acre on March 1, 2009. Broadleaved by Jagadeesh Mosali, J. Guretzky, M. Saha and S. Norton Agricultural Division 2510 Sam Noble Pkwy. Ardmore, OK 73401 Forage Yields from 2008-2009 Ryegrass Variety Trial weeds were controlled with an application of 2,4-D amine at a rate of one pt/ac during January 2009. Plots were harvested with a HEGE sickle bar forage plot harvester at a 3-inch height on April 21 and May 20, 2009. Data was analyzed with the general linear models procedure in SAS (Statistical Analysis Software, Cary, N.C.), and means were separated by the least significant difference (LSD) method (P ≤ 0.05)

Effect of Nitrogen Fertilizer Rate and Harvest Season on Forage Yield, Quality, and Macronutrient Concentrations in Midland Bermuda grass

Bermuda grass [Cynodon dactylon (L.) Pers.] is a major forage for grazing and hay production in the southern United States. The objectives of this study were to determine effects of nitrogen (N) fertilization rate (0, 112, 224, 336, and 448 kg ha−1), split spring and summer applications of N at the 224 and 448 kg ha−1 rates, and harvest periods (spring and summer) on forage yield, crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN), and concentrations of phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca) in Midland Bermuda grass. Data were collected from 2002 to 2008 as part of an ongoing, long-term soil fertility experiment in southern Oklahoma. Repeated measures analysis of these long-term data showed that forage yield responses to N rate varied with year and harvest time with up to 2.5-fold yield differences among years. Nitrogen fertilization increased CP, TDN, and macronutrient P and Mg and decreased ADF and NDF. Crude protein was increased by ≥50%, and ADF and NDF dropped by up to 25% with the greatest N rate. In general, split N applications did not affect forage yield but produced low-quality forage compared to single N application in spring. Split application of 448 kg N ha−1 gave forage with CP, TDN, ADF, and NDF similar to the Bermuda grass receiving 336 or 448 kg N ha−1 as a single application. Spring forage had better forage quality than summer harvests. While N fertilization increased forage Mg and P concentrations by more than 50% during both spring and summer, it had no effect or slight increased K and Ca concentrations. In the southern Great Plains, despite the weather-dependent variability in forage yield of Bermuda grass, N application increase forage quality