Showing papers in "Journal of Production Agriculture in 1993"
TL;DR: In this paper, the authors developed an indexing procedure for identifying soils, landforms, and management practices that could have unfavorable impacts on water bodies because of P movement, using the characteristic of the field site, including soil erosion rates, runoff, available P soil test levels, and fertilizer and organic P application rates.
Abstract: Nonpoint sources of P leaving the agricultural landscape can cause eutrophication of surface water and the associated growth of undesirable aquatic plants. USDA is developing an indexing procedure for identifying soils, landforms, and management practices that could have unfavorable impacts on water bodies because of P movement. This indexing procedure uses the characteristic of the field site, including soil erosion rates, runoff, available P soil test levels, and fertilizer and organic P application rates and methods to assess the degree of vulnerability of P movement from the site. A weighting procedure has been developed to include the various contributions each site characteristic may have. A summation of the products of the weighted site characteristic yields a site vulnerability rating [...]
480 citations
TL;DR: The main factors controlling P movement are transport (runoff and erosion potential) and source factors (surface soil P and method, rate, and timing of fertilizer and animal manure applications) as discussed by the authors.
Abstract: Phosphorus movement in runoff often promotes algal growth in lakes. Thus, agricultural soils and management practices that enhance the potential for P movement must be identified. The main factors controlling P movement are transport (runoff and erosion potential) and source factors (surface soil P and method, rate, and timing of fertilizer and animal manure applications). Implementation of management that minimizes runoff and erosion will reduce P transport in runoff, although total algal availability can increase. The continued application of P has increased surface soil test P contents in excess of levels sufficient for optimum crop yields. Although increases in soil P have been related to P enrichment of runoff in plot and watershed studies, information for given management systems still is needed to reliably quantify critical soil P levels above which excessive P enrichment of runoff will occur [...]
279 citations
TL;DR: In this article, the influence of soil fertility variation was considered with soil sampling on a grid pattern and with detailed soil maps made of each field, where fields, located in eastern North Dakota, were mainly a mixture of Haploborols, Calciaquolls, and Argialbolls.
Abstract: Soil fertility and soil productivity are variable within farm fields. Over or under application of a nutrient in parts of every field can result from conventional fertilizer application. This study was conducted to determine whether yield and net returns could be increased by considering field variability when applying fertilizer. The influence of soil fertility variation was considered with soil sampling on a grid pattern and with detailed soil maps made of each field. The fields, located in eastern North Dakota, were mainly a mixture of Haploborols, Calciaquolls, and Argialbolls. Wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) were grown. In 1989, variable rate fertilization based on grid soil sampling did not result in a greater yield of barley (32.1 bu/acre) than the conventional method (30.0 bu/acre) [...]
120 citations
TL;DR: The goal was to develop a means to predict the optimum stage for harvesting corn for silage, and to determine the relationship between kernel milkline position and whole plant yield, quality, and dry matter content.
Abstract: Determining the proper time to harvest corn (Zea mays L.) for whole plant silage is difficult for growers. The objective of this study was to determine the relationship between kernel milkline position and whole plant yield, quality, and dry matter (DM) content. Our goal was to develop a means to predict the optimum stage for harvesting corn for silage. Four early maturity (85 d) hybrids were evaluated bor yield, forage quality, and DM content at five stages of kernel maturity, including: soft dough (SD) (dents first visible); early dent (ED) (dents visible on 95% of kernels); 1/2 milkline (1/2 ML) (milkline positioned halfway between the tip and base of the kernel); 3/4 milkline (3/4 ML) (milkline positioned 3/4 of the way from tip to base); and no milkline (No ML) (milkline no longer present in kernel) over 3 yr (1988-1990) in north central Wisconsin []
116 citations
TL;DR: The roles soil testing programs can play in the development of nutrient management strategies, such as the P index, that are needed to minimize nonpoint source pollution by soil P are discussed.
Abstract: Many soils in the USA have extremely high soil test P levels from long-term fertilization and manuring. Sediment-bound and soluble P in runoff from these soils may contribute to eutrophication of surface waters. A field rating system, the «P index,» has been developed to assess the potential for soil P to contribute to nonpoint source pollution. A critical component in this index is soil test P. The primary objective of this paper is to discuss the roles soil testing programs can play in the development of nutrient management strategies, such as the P index, that are needed to minimize nonpoint source pollution by soil P. A survey of soil testing labs participating in four regional soil testing committees (North Central, Northeast, Mid-Atlantic, Southeast) was conducted in 1991-1992 to determine current approaches to soil P testing, the percentage of soils testing in the high or excessive range, and major concerns with high P soils [...]
116 citations
TL;DR: In this article, the authors conducted a study in four major poultry producing counties in the Sand Mountain region to determine the effects of long-term litter use on soil and plant conditions related to pasture production and borage quality.
Abstract: Alabama's poultry industry is most heavily concentrated in the Sand Mountain region of northern Alabama. Disposal of litter (manure and bedding material) generated from poultry production in the region is typically accomplished by landspreading onto tall fescue (Festuca arundinacea Schreb.) pastures. We conducted a study in four major poultry producing counties in the Sand Mountain region to determine the effects of long-term litter use on soil and plant conditions related to pasture production and borage quality. Soil samples from 0 to 6 in. depth and plant tissue samples were collected from tall fescue pastures receiving annual applications of litter for 15 to 28 yr (littered) or not receiving such applications (nonlittered). These samples were analyzed for soil pH and organic matter, plant nitrate-N, soil and plant total N, and extractable P, K, Ca, Mg, Cu, Fe, Mn, and Zn [...]
97 citations
TL;DR: The objectives of this study were to determine whether corn or soybean yields could be increased in 3-yr rotations with wheat compared with an annual rotation with each other, and to evaluate the influence of tillage on performance of corn, soybean, and winter wheat in rotationsWith each other.
Abstract: There is little research in northern regions on tillage systems in corn (Zea mays L.), soybean [Glycine max (L.) Merr], and wheat (Triticum aestivum L.) rotations. The objectives of this study were to (i) evaluate the influence of tillage on performance of corn, soybean, and winter wheat in rotations with each other, and (ii) determine whether corn or soybean yields could be increased in 3-yr rotations with wheat compared with an annual rotation with each other. Field studies were conducted near Arlington, WI, for 3 yr (1989 to 1991) on a Plano silt loam soil (fine-silty, mixed, mesic Typic Argiudoll) under both moldboard plow (MP) and no-till (NT). Six crop sequences evaluated were: corn/soybean, corn/soybean/wheat, corn/wheat/soybean, and continuous corn, soybean, or wheat [...]
88 citations
TL;DR: The effect of SDS disease severity on leaf nutrient content and on soybean yield and seed germination were determined and the combinations of soil fertility parameters and soybean cyst nematode second stage juvenile (J2) population levels were associated with SDS severity.
Abstract: Sudden death syndrome (SDS) of soybean (Glycine max [L.] Merr.) is a soilborne disease of increasing importance in high-yield environments. This study was conducted to determine which combinations of soil fertility parameters and soybean cyst nematode (Heterodera glycines Ichinoe) (SCN) second stage juvenile (J2) population levels were associated with SDS disease severity. Also, the effect of SDS disease severity on leaf nutrient content and on soybean yield and seed germination were determined. These studies were conducted at the Pine Tree Station, in Colt, on a Crowley milt loam (fine, montmorillonitic, thermic Typic Albaqualfs) over 3 yr with the soybean cultivar Lee 74 [...]
69 citations
TL;DR: In this article, field experiments were conducted at seven locations from 1990 to 1991 in Alabama to determine soybean response to N fertilization at vinous growth stages, which included a factorial arrangement of soybean cultivar ('Stonewall' or 'Sharkey') and N rate/timing treatments in a split plot design.
Abstract: While previous research has been contradictory, potential grain yield responses and seed protein increases have led to continuing interest in N fertilizer application to soybean (Glycine max (L.) Merr.]. Field experiments were conducted at seven locations from 1990 to 1991 in Alabama to determine soybean response to N fertilization at vinous growth stages. Treatments included a factorial arrangement of soybean cultivar ('Stonewall' or 'Sharkey') and N rate/timing treatments in a split plot design. Nitrogen rate/timing treatments were: (i) no N, (ii) 30 Ib N/acre at planting, (iii) 50 Ib N/acre at first bloom (R1), and (iv) 50 Ib N/acre at early pod fill (R5). Plant samples were collected at R1 and R5 for dry matter yield and N determination. Grain yields were determined and grain samples were collected at harvest for protein and oil analyses [...]
65 citations
TL;DR: In this article, a field study was developed to determine the yields that could be attained in minimum till cropping systems that included winter wheat (Triticum aestivum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.] and grain sorghum [Sorghum bicolor (L.' Moench] under dryland farming, and limited and full irrigation.
Abstract: Declining groundwater levels in irrigated areas of the Great Plains may require a shift to limited irrigation or a return to dryland production. A field study was developed to determine the yields that could be attained in minimum till cropping systems that included winter wheat (Triticum aestivum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.] and grain sorghum [Sorghum bicolor (L.) Moench] under dryland farming, and limited and full irrigation. The limited irrigation allocation was 6 in./crop/year. The experiment began in 1981 on a Cozad silt loam (fine-silty, mixed, mesic Fluventic Haplustoll) at North Platte, NE, where average annual precipitation was 19.4 in. Management practices for fertilizer, herbicide, variety selection, and pest management were modified as improved varieties, technology, and products became available [...]
64 citations
TL;DR: This study was conducted to determine if the PSNT could be used for corn (Zea mays L.) production to identify N responsive and nonresponsive sites, predict the economic optimum fertilizer N rate, and improve the current fetilizer N recommendation procedure.
Abstract: Proper N management is important to optimizing profit and minimizing N loss. The efficiency of N use may be improved in humid regions with a reliable soil test to guide fertilizer N recommendations. Recently, a presidedress nitrate soil test (PSNT) has shown promise as a means of quantifying the size of the potential mineralizable organic N pool in soil. This study was conducted to determine if the PSNT could he used for corn (Zea mays L.) production to identify N responsive and nonresponsive sites, predict the economic optimum fertilizer N rate, and improve the current fetilizer N recommendation procedure. The PSNT gave a useful and defined critical level of 21 ppm nitrate-N, delineating N responsive from nonresponsive sites. The success rate for making the correct decision about N responsiveness was 84%, indicating a good relationship between the PSNT and the ability of the soil to supply N [...]
TL;DR: A spreadsheet (Milk90) was developed that combines yield and quality into a single term using the concept of milk produced per acre of forage, which assumes maximum forage use and approximates a balanced ration given the forage quality.
Abstract: Improvements in forage quality have historically been difficult to quantify or determine cost/benefits. A spreadsheet (Milk90) was developed that combines yield and quality into a single term using the concept of milk produced per acre of forage. Forage yield and quality, animal production, and inputs costs can be varied. The spreadsheet assumes maximum forage use and approximates a balanced ration given the forage quality, with corn (Zea mays L.) and soybean (Glycine max L.) meal used as the energy and protein sources, respectively. Milk from forage is determined as the percentage of total ration energy coming from forage times total milk production less animal maintenance requirement. Milk per acre is calculated as milk per ton of forage times forage yield [...]
TL;DR: The purpose of this paper is to review the literature on crop, soil, and management factors which may be used as indirect measures of soil test P to help reduce surface water quality problems associated with excessive P concentrations.
Abstract: There is renewed interest in reducing surface water quality problems associated with excessive P concentrations. A P site index has been proposed that qualitatively ranks sites based on their potential for off-site P movement. Soil test P is one of eight site characteristics used in calculating the current P site index. The purpose of this paper is to review the literature on crop, soil, and management factors which may be used as indirect measures of soil test P. Crop, soil, and management factors can influence soil test P in a variety of ways. It is quite probable that anticipated crop P removal at a particular site would reflect soil P test, and an extensive table was developed outlining P removal for numerous crops. Crops or crop rotations using relatively high P inputs will have higher soil P tests [...]
TL;DR: The rate of N fertilization most profitable when applied across the 29 fields was mainly determined by cost of fertilization and value of grain, and applications of 0 and 25 Ib N/acre were the most profitable.
Abstract: Alfalfa (Medicago sativa L.) contributes substantial N to grain crops that follow, but there is uncertainty concerning the amounts. The objective of this study was to determine optimal rates of N fertilization for first-year corn (Zea mays L.) grown after alfalfa. Fertilizer N was applied at seven rates, ranging from 0 to 200 Ib/acre, at 29 trials conducted over 4 yr in northeast Iowa. Concentrations of soil nitrate in late spring and concentration of nitrate in cornstalks at the end of the season were used to help determine optimal N rates. Fertilizer significantly increased yields at six of the 29 trials. The rate of N fertilization most profitable when applied across the 29 fields was mainly determined by cost of fertilization and value of grain. At prices prevailing in the Corn Belt, applications of 0 and 25 Ib N/acre were the most profitable [...]
TL;DR: No-till corn following a hairy vetch cover crop yielded more than no-t Till corn following winter fallow and winter wheat cover crops at comparable fertilizer N rates in the Coastal Plain and Piedmont over 3 yr.
Abstract: Hairy vetch (Vicia villosa Roth subsp. villosa), as a winter legume cover crop, fixes atmospheric N 2 for following crops and improves the soil. A 3-yr field study (1985-1988) was conducted in the Maryland Coastal Plain and Piedmont to assess the agronomic and economic characteristics of a hairy vetch cover crop on no-till corn (Zea mays L.) compared with corn systems preceded by winter fallow and winter wheat (Triticum aestivum L.) cover crops. No-till corn following a hairy vetch cover crop yielded more than no-till corn following winter fallow and winter wheat cover crops at comparable fertilizer N rates in the Coastal Plain and Piedmont over 3 yr. The highest yielding combinations were a hairy vetch cover crop with 120 Ib N/acre in the Coastal Plain and a hairy vetch cover crop with 40 Ib N/acre in the Piedmont [...]
TL;DR: In this paper, a study was conducted to determine whether winter wheat seeding rates should be altered depending on planing date and cultivar, and the results showed that grain yield and yield components were influenced by all variables and specific interactions.
Abstract: Winter wheat (Triticum aestivum L.) is commonly seeded over a 60-d period in the Midwest depending on crop rotation options, weather, and other farm operations. This study was conducted to determine whether winter wheat seeding rates should be altered depending on planing date and cultivar. Seeding date and planting rate responses of the cultivars, Merrimac and Cardinal, were evaluated at the University of Wisconsin Arlington Research Station during the 1988 to 1991 growing seasons. Eight planting dates ranged from 24 August to 3 November and seeding rates were 14, 28, 42, and 56 seeds/sq ft. Grain yield and yield components were influenced by all variables and specific interactions. Heads per square feet and kernel weight, two primary yield components, decreased as seeding was delayed after 12 September [...]
TL;DR: Economic and environmental incentives to accurately predict corn (Zea mays L.) N requirements emphasize the need to accurately credit N supplied to first-year corn from a previous alfalfa (Medicago sativa L.) crop.
Abstract: Economic and environmental incentives to accurately predict corn (Zea mays L.) N requirements emphasize the need to accurately credit N supplied to first-year corn from a previous alfalfa (Medicago sativa L.) crop. A 4-yr study (24 site-yr) was conducted to evaluate the use of preplant and pre-sidedress soil and basal stalk nitrate tests and an end-of-season stalk nitrate test to assess N availability to first-year corn following alfalfa. Pre-sidedress soil and basal stalk samples were obtained when corn was 6 to 12 in. tall and analyzed for nitrate. Grain yield was not significantly increased by applied N at any location during the study [...]
TL;DR: Legume winter ground covers may contribute to row crop systems by providing protection from wind and precipitation and by releasing N to the subsequent row crop, but to attain effective size, these legumes must begin growth well before the winter.
Abstract: Legume winter ground covers may contribute to row crop systems by providing protection from wind and precipitation and by releasing N to the subsequent row crop, but to attain effective size, these legumes must begin growth well before the winter. A 3-yr study was conducted to evaluate the performance of four commonly used forage legumes interseeded into corn (Zea mays L.). Alfalfa (Medicago sativa L.), yellow sweetclover (Melilotus officinalis Lam.), red clover (Trifolium pratense L.), and alsike clover (T. hybridum L.) were seeded in a mix consisting of equal seed numbers (pure live seed) from each species. Seeding dates were (i) at corn planting and (ii) at last cultivation. Control treatments were nonseeded. Two levels of weed control also were evaluated [...]
TL;DR: Field and lab studies demonstrated that when the soil nitrate levels were greater than 15 ppm and conditions were favorable for effective nodulation, using preplant N fertilizer in alfalfa establishment did not result in economically important yield increases.
Abstract: Nitrogen fertilization of alfalfa (Medicago sativa L.) at establishment has been a controversial practice. A review of the literature was conducted to determine conditions when preplant N fertilization of alfalfa resulted in increased yields in the seeding year. Field and lab studies demonstrated that when the soil nitrate levels were greater than 15 ppm and conditions were favorable for effective nodulation (soil pH from 6.2 to 7.5 and high populations of appropriate Rhizobium bacteria present), using preplant N fertilizer in alfalfa establishment did not result in economically important yield increases. Under field conditions that inhibit effective nodulation, alfalfa yield in the seeding year increased when a small amount of N fertilizer (10-50 Ib N/acre) was applied []
TL;DR: In the eastern region of the Great Plains, yield and seed quality of wheat could potentially be increased by applying additional N and foliar fungicide by evaluating responsiveness of cultivars of hard and soft winter wheat.
Abstract: In the eastern region of the Great Plains, yield and seed quality of wheat could potentially be increased by applying additional N and foliar fungicide. Field studies were conducted at two locations in southeastern Kansas from 1987 through 1990 on a Parsons silt loam soil (fine, mixed, thermic, Mollic Albaqualf) to evaluate responsiveness of selected cultivars of hard and soft winter wheat to conventional N (75 Ib N/acre, fall-applied) and high N (75 Ib N/acre, fall-applied followed by 50 Ib N/acre topdressed in late winter) fertilizer applications, with and without foliar fungicide (propiconazole - 1[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl] methyl]-1H-1,2,4-triazole). Nitrogen level and foliar fungicide responses varied significantly among cultivars, locations, and years []
TL;DR: In this article, the authors evaluated corn yield and N fertilizer recovery following 0, 4, or 6 in. of excess soil water, at field capacity (0.33 bar), with an additional 50 Ib N/acre being applied to half the plot following the water stress treatments.
Abstract: Optimum N management for soils which can have short-term, early-season periods of excessive soil water requires farmers to balance economic and environmental concerns. The objectives of this study were to evaluate corn (Zea mays L.) yield and N fertilizer recovery following 0, 4, or 6 in. of excess soil water. Field studies were conducted from 1985 to 1988 on Cisne silt loam (fine, montmorillonitic, mesic Mollic Albaqualf), Drummer silty clay loam (fine-silty, mixed, mesic Typic Haplaquoll), and Plainfield sand (mixed, mesic Typic Udipsamment) at three Illinois locations. Water stress was imposed by applying 0, 4, or 6 in. of water to soils at field capacity (0.33 bar). Fertilizer rates ranged from 0 to 200 Ib N/acre with an additional 50 Ib N/acre being applied to half the plot following the water stress treatments [...]
TL;DR: In this paper, the authors make the assumption that agriculture faces an uncertain future and, therefore, must rely upon experience, adoption of proven technologies, development of new technologies, and improved husbandry of land, water, and energy resources.
Abstract: What should U.S. agriculture do to adapt for possible climate change and what can it do to reduce greenhouse gas emissions? An evaluation indicates that, unless there is a decline of about one-fourth in total crop yields, the U.S. land resource base will be adequate and food security can be met. The impacts of climate change on individual crop production regions are hard to predict, however, and may be either negative or positive. The assumption must be made that agriculture faces an uncertain future and, therefore, must rely upon experience, adoption of proven technologies, development of new technologies, and improved husbandry of land, water, and energy resources [...]
TL;DR: When averaged over 5-yr, grain yields were less with urea-ammonium nitrate (UAN) broadcast and dribbled treatments than with anhydrous ammonia (AA) preplant knifed, 28% UAN solution preplant KNIFed, and split applications of UAN knifing or dribbled.
Abstract: Use of conservation tillage methods, including ridge-tillage increases crop residue cover which can increase loss of urea-based fertilizers. Objectives of this study were to evaluate N sources, rates, methods, and times of application for ridge-tilled, furrow-irrigared corn (Zea mays L.) on a Crete silt loam soil (fine, montmorillionic, mesic Pachic, Argiustoll) near Scandia, KS. When averaged over 5-yr, grain yields were less with urea-ammonium nitrate (UAN) broadcast and dribbled treatments than with anhydrous ammonia (AA) preplant knifed, 28% UAN solution preplant knifed, and split applications of UAN knifed or dribbled. Surface dribbled UAN proved to be no more effective than surface broadcasting [...]
TL;DR: This work wanted to determine if the urease inhibitor amendments ammonium thiosulfate (ATS) and N-(n-butyl)thiophosphoric triamide (NBPT) would increase the N fertilizer use efficiency of UAN and urea surface applied to no-till corn.
Abstract: No-till corn (Zea mays L.) production is common in the Mid-Atlantic region and urea-ammonium nitrate solution (UAN) and urea are by far the most common N fertilizers used in the region. Because of the potential for ammonia volatilization from these sources when they are surface-applied to no-till corn, it is necessary to know how the method and time of application affect the N fertilizer use efficiency (grain yield, N uptake, and ear-leaf N concentration per pound of N applied) obtained with them. We also wanted to determine if the urease inhibitor amendments ammonium thiosulfate (ATS) and N-(n-butyl)thiophosphoric triamide (NBPT) would increase the N fertilizer use efficiency of UAN and urea surface applied to no-till corn [...]
TL;DR: In a long-term tillage experiment comparing no-tillage, stubble mulch tillage, and hare soil (moldboard plow) tillage was measured during two 14-mo fallow periods in an 114in annual precipitation area in north-central Oregon.
Abstract: Information concerning soil water storage with no-tillage fallow in the semiarid winter wheat (Triticum aestivum L) production areas of the Pacific Northwest is limited Soil water storage in a long-term tillage experiment comparing no-tillage, stubble mulch tillage, and hare soil (moldboard plow) tillage was measured during two 14-mo fallow periods in an 114-in annual precipitation area in north-central Oregon The greatest precipitation storage efficiency during both years was achieved with stubble mulch tillage, followed by the bare soil and no-tillage systems Residue cover in the no-tillage treatment retarded evaporation during periods of frequent precipitation and low potential evaporation during the spring, but water loss from no-tillage fallow occurred at the fastest rate during the dry summer due to uninterrupted capillary flow []
TL;DR: The objective of this study was to demonstrate the long-term consequences of withholding fertilizer N and P on wheat yields, and to determine if inclusion of legume-green manures (GM), or hay crops in rotations can maintain wheat yields.
Abstract: The benefits and environmental impacts of using fertilizers rather than legumes to promote more sustainable agricultural production systems are in question. The objective of this study was to demonstrate the long-term consequences of withholding fertilizer N and P on wheat (Triticum aestivum L.) yields, and to determine if inclusion of legume-green manures (GM), or hay crops in rotations can maintain wheat yields. A 34-yr crop rotation experiment being conducted at Indian Head, Saskatchewan, on a Udic Haploboroll with heavy clay texture, was used to assess the influence of fertilizer (N and P), sweetclover (Melilotus officinalis L.) GM, and alfalfa-bromegrass (Medicago sativa L. - Bromus inermis Leyss.) hay on yield trends of hard red spring wheat grown on wheat stubble in rotations of varying cropping intensity [...]
TL;DR: This research was conducted to develop high- protein soybean germplasm adapted to Mid-Atlantic latitudes and compare agronomic performance, economic value, and stability of performance of resulting genotypes with that of normalprotein soybean cultivars.
Abstract: The long-term trend in relative value of soybean [Glycine max (L.) Merr.] protein and oil is toward greater value of protein, thus furthering interests in the potential for increasing seed protein concentration in soybean. If a change in U.S. soybean breeding strategy for improving seed protein levels is required, it should be based on sound economic and biological principles. This research was conducted to: (i) develop high-protein soybean germplasm adapted to Mid-Atlantic latitudes; and (ii) compare agronomic performance, economic value, and stability of performance of resulting genotypes with that of normal-protein soybean cultivars. Fifty-two high-protein soybean lines were developed and evaluated in field tests in 1988 and 1989. Seven of the highest yielding high-protein lines, seven advanced commercial lines, and ‘Essex’ were evaluated in 11 field tests in 1990. All lines in all tests were evaluated for seed protein and oil, seed yield, and other agronomic characters. High-protein lines were: (i) superior for seed protein concentration and approximate processed value (APV) per bushel; (ii) inferior for seed yield and oil concentration and APV per acre; and (iii) less able to use environmental yield potential, with a decreased seed protein and increased seed oil, as compared with commercial cultivars. Extensive regional testing, including environments with very high seed yield potential, will be required to more precisely describe the biological and economic trade-offs for high-protein vs. normal-protein soybeans. Research QuestionThere is continuing interest in increasing seed protein concentration in soybean. This research was conducted to: (i) develop high-protein soybean lines adapted to Mid-Atlantic latitudes; and (ii) compare agronomic performance, economic value, and stability of performance of high-protein genotypes with that of normal-protein soybean cultivars. Literature SummaryFor more than half a century, U.S. soybean breeding has produced improved, higher yielding cultivars. Seed of current cultivars average approximately 41% protein and 21% oil on a dry weight basis. Seed protein and oil are highly negatively correlated in soybean, and seed protein usually is negatively correlated with seed yield. The approximate processed value (APV) per bushel of soybean can be estimated from the soybean's protein and oil concentration and prices for oil and 44% meal. Environmental factors that influence soybean seed yield and protein include soil fertility, N nutrition, temperature, water stress, and soil pH. Stability of performance of a line, the ability to exhibit minimum interaction with the environment, can be determined by regressing the seed yield or other character of each line for each environment on the mean yield of all lines in those environments. Study DescriptionFifty-two high-seed-protein soybean lines were developed from 18 crosses of high protein × high protein germplasm via phenotypic selection at Beltsville, MD, for plant maturity, lodging resistance, seed yield, and seed quality. These 52 lines were compared with the two best adapted high-protein parental lines in two 1988 field tests. In 1989, these 54 high-protein lines and six commercial, normal-protein cultivars were evaluated in six Mid-Atlantic field tests, cooperatively with state agricultural experiment stations. In 1990, private industry coordinated the evaluation of the seven highest yielding high-protein lines, seven advanced commercial lines, and ‘Essex’ in six Mid-Atlantic and five Mid-Mississippi Valley field tests. All field tests were evaluated for seed yield, protein, and oil and other agronomic characteristics via conventional soybean plot technique. Applied QuestionsHow does the agronomic performance of high-protein soybean lines developed for Mid-Atlantic latitudes compare with that of current cultivars? The high-protein lines were comparable for lodging resistance and seed quality but were not as high yielding as Essex or other commercial lines. In 16 field tests, the highest yielding high-protein line averaged 90% of the seed yield of Essex, 48 vs. 53 bu/acre. In 1990, the mean yields of seven high-protein lines ranged from 40 to 49 and averaged 43 bu/acre. Commercial lines ranged from 54 to 59 and averaged 56 bu/acre. What is the potential value of high-protein soybean, assuming the values of $0.20/lb for oil and for protein? The seven highest yielding, high-protein lines evaluated at 11 locations in 1990 averaged 50.3% seed protein and 15.5% seed oil, compared with the mean of 41.2% protein and 20.7% oil for eight commercial lines. The APV per bushel of these high-protein lines ranged from $6.71 to $7.03, compared with $6.42 to $6.53 for commercial lines. The APV per acre (APV/bu × bu/acre) of these high-protein lines ranged from $270 to $326, compared with $348 to $382 for commercial lines. Do high-protein soybean lines respond to high yield environments as well as commercial lines? In 1989, mean seed yields of the 54 high-protein lines and of commercial lines increased ≈ 1.0 and 1.5 bu/acre, respectively, with each 1.0 bu/acre increase in mean seed yield of environments. In 1990, the high-protein lines and commercial lines increased 0.93 and 1.06 bu/acre, respectively, with each 1.0 bu/acre increase in mean seed yield of environments. In 1990, the mean seed yields of environments ranged from 33 to 64 bu/acre. The estimated changes in seed yield, protein, and oil per 31 bu/acre increase in seed yield over environments are summarized in Table 1. Compared with commercial lines, the high-protein lines had less seed yield response, greater drop in protein, and an increase rather than a decrease in oil in higher yielding environments. We conclude that high-protein soybean lines probably differ from normal-protein lines in response to increasing seed yield potential of field environments. RecommendationsMore accurate estimates must be obtained to provide conclusive evidence on stability of high-protein vs. normal-protein soybean. Comparisons of higher yielding, high-protein (> 50%) vs. commercial, normal-protein lines should be made in a great number of environments ranging in yield from U.S. average to highest attainable yields. Changes in soybean breeding strategies to improve seed protein levels should be based on: (i) the econometrics of maximizing net returns to soybean producers; and (ii) known and rational interrelationships among seed yielding ability of genotypes and their protein, oil, and residual fractions of the seed. Table 1Estimated changes in seed yield, protein, and oil of commercial and high-protein soybean lines per 31 bu/acre increase in mean seed yield of environments. Changes inMean of:YieldProteinOilbu/acre------ % ------8 commercial lines+33−0.7−0.67 high-protein lines+29−1.8+0.5
TL;DR: Whether increased grain yields of semidwarf cultivars result from increased biological yield, improved partitioning (harvest index [HI], improved N responsiveness (for example, improved fertility), or some combination of these factors is investigated.
Abstract: The widespread adoption of high yielding, semidwarf, N-responsive rice (Oryza sativa L.) cultivars by California rice growers in the late 1970s raised questions about improved fertilizer use efficiency and reduced straw production of semidwarf rice cultivars under direct, water-seeded cultural systems. The objective of this study was to determine whether increased grain yields of semidwarf cultivars result from increased biological yield, improved partitioning (harvest index [HI]), improved N responsiveness (for example, improved fertility), or some combination of these factors. Twelve field experiments that included 12 cultivars were conducted from 1976 through 1985 at five locations, with preplant applied N rates ranging from 0 to 210 Ib/acre. No differences in biological yield were observed between tall and semidwarf cultivars across all N rates [...]
TL;DR: The objective of this study was to determine effects of tillage history on diseases, growth, and yield of spring barley in semi-arid eastern Oregon.
Abstract: Spring barley (Hordeum vulgare L.) grown annually in a high-residue management system has been favorably viewed as a means of reducing soil erosion without compromising income from traditional winter wheat (Triticum aestivum L.)/fallow rotations in the northwestern USA. Rhizoctonia root rot (R. solani Kuhn), however, is more severe on barley than on wheat, especially in nontilled soil. Constraints of this disease to spring barley production without tillage are not known. The objective of this study was to determine effects of tillage history on diseases, growth, and yield of spring barley in semi-arid eastern Oregon. Spring barley was produced at two locations under a moldboard plow-based system, a no-till system, or various sequences of tillage alternated with no-till [...]
TL;DR: In this paper, two process simulation models (EPIC and GLEAMS) were combined with a farm level linear programming model to assess the economic and environmental implications of selected eastern Corn Belt farming systems.
Abstract: Output from two process simulation models (EPIC and GLEAMS) was combined with a farm level linear programming model to assess the economic and environmental implications of selected eastern Corn Belt farming systems. The farm level economic results suggest that an alfalfa (Medicago sativa L.)based cropping system is generally less profitable than a corn-soybean (Zea mays L.-Glycine max L. [Merr.]) rotation produced under farm program prices or recent average market price conditions. Net returns are projected to decline by approximately 38% if alfalfa is included in an eastern Corn Belt cropping system. The adoption of a corn-alfalfa cropping system could reduce annual soil erosion and the quantity of nitrates in surface water runoff relative to a conventional corn-soybean rotation [...]