AbstractGrain protein is important in human and animal nutrition and in relation to various culinary uses of flour. Various wheat (Triticum aestivum L.) cultivars are reported to vary widely in grain yield and protein concentrations. To study yield‐protein relationships, three soft red winter (Atlas 66, Knox 62, and Blue Boy) and three hard red winter (Norin 16, Tascosa, and Omaha) wheat cultivars were grown in a pot experiment at Muscle Shoals, Alabama. Response to 0, 100, 200, 400, 800, and 1,200 mg of N/pot (3 kg of Mountview silt loam) together with adequate, uniform rates of other nutrients was determined.All cultivars increased similarly in grain and straw yields, crude protein concentrations, and crude protein / pot with amount of applied N. The ranking for grain yields was: Tascosa > Blue Boy = Knox 62 > Omaha > Norin 16 > Atlas. The ranking for crude protein concentrations was in the reverse order. These trends indicate pronounced genetic differences among cultivars. At each rate of applied N, protein concentrations were also inversely related to grain and straw yields. Early uptake of N at forage and boot stages of growth was usually highly correlated with uptake in grain + straw at maturity. Nitrogen and moisture supply, light, temperature, and other growth factors greatly affect yield‐protein relationships among cultivars. Differences among cultivars tended to be greatest under optimum growth conditions.

Six greenhouse pot experiments were conducted in which yield and nutrient uptake responses of corn (Zea mays L.) or tall fescue (Festuca arundinacea Shreb) to N, P, K, lime, or temperature variables were measured. This paper describes yield—NO3‐N and total N concentration trends in these experiments. Crop concentrations of total N and NO3‐N during early growth increased consistently with amount of applied N. These concentrations usually decreased (by dilution and assimilation) with time of growth and yield response to other growth‐limiting nutrients and other factors. Concentrations of K also increased in corn with amount of applied K, and high K was associated with higher concentrations of NO3‐N during early growth in some experiments. This was usually true only for early crop growth periods during which rates of nutrient uptake exceeded growth rate. High K concentrations may have retarded growth and NO3‐N reduction and assimilation.

AbstractPublished results suggest that low rates of applied N may have been responsible for low yields and grain protein of rice (Oryza sativa L.) grown in pot experiments. A series of greenhouse pot experiments was, therefore, conducted at Muscle Shoals, Ala., with rice grown under continuous flooding on Sango sicl (Ochrepic Fragiudult, 5 kg/pot) to study effects of rate and source of applied N (up to 5.0 g/pot) on yield, N recovery, and grain protein. Uniform high rates of other nutrients were applied.Urea or ammonium sulfate mixed with the soil before planting markedly increased yield of both grain and straw, but NO3‐N was largely lost by denitrification. Rates of 0.5 to 1.0 g of non‐NO3‐N were required for early growth and tillering, factors which were well correlated with grain yield at maturity. Urea and ammonium sulfate topdressed in the floodwater after tillering were more effective than NO3‐N and increased yield of grain proportionately more than straw, as compared to application of all N prior to planting. Grain and straw yields increased curvilinearly with higher N rates, but uptake of N was highly rectilinear with all rates of applied N. Grain protein also increased with rate of N (from 7 to 3% with no N to 9 to 12% with 2 to 5 g of N/pot). Thus, adequate rates and timing of applied N increased both yield and protein content of grain in these pot experiments (without lodging being a problem). These responses varied among sources, methods and time of application, and cultivars; but maximum yield was invariably obtained from rates of N much higher than commonly reported for pot experiments.

AbstractSlow‐release fertilizers should provide for more efficient nutrient use by the crop as well as reduce leaching losses. This study was conducted to measure crop response to N or K in uncoated urea, ammonium nitrate (AN), S‐coated urea (SCU), KCl, and S‐coated KCl (SCK) and to relate leaching losses to NO3‐Nan and cations. In one series, granular N sources to supply 200 or 400 kg of N/surface ha were mixed with the upper 20 cm of a 1:1 mixture of Norfolk s1 (Typic Paleudult) and builders sand contained in 15‐ ✕ 120‐cm columns. A second series was similarly fertilized with K sources to supply 100 or 200 kg of K/surface ha.Soil columns were left fallow or planted to tall fescue (Festuca arundinacea Shreb. ‘Kentucky 31’) which was harvested six times at 4‐week intervals. Following the sixth harvest of fescue, stubble and roots were incorporated into the soil along with a second application of N or K and cultures were planted to sorghum‐sudangrass (Sorghum bicolor ✕ Moench Sorghum vulgare sudanense ‘Green M’), which was harevsted four times at 4‐week intervals. Water was applied as required for crop growth and once during each growth period all columns (including fallow) were heavily watered to collect liters (10 cm) of leachate from each.Total recovery of N by both crops was in the order: SCU‐12 > split‐AN > SCU‐20 > urea > AN > no N. With cropping, 0 to 11% of applied N was found in drainage water. Under fallow, losses of N were much higher (29 to 72%) and were in the order: split‐AN > SCU‐12 = SCU‐20 > AN = urea > no N. These results support the premise that slow‐release fertilizers supply more N for crop response, but may not reduce leaching losses. Leaching of cations was well correlated with loss of NO3‐N (r = 0.83 to 0.90) under fallow, but was less correlated (r = 0.33 to 0.74) under grass.Recovery of K by both crops was near 100%. Applied K decreased loss of NO3‐N, Ca, and Mg under cropping and increased losses under fallow. Leaching of NO3‐N and cations was highly correlated. Applied N and oxidation of S in S‐coated products both contributed to acidification of the soil, which intensified leaching of Ca and Mg.

Pot experiments were conducted to determine effects of applied N on NO3‐N and total N concentrations in Swiss chard (Beta vulgaris var. cicla) and of applied N, P, and K on Bloomsdale spinach (Spinacia oleracea L.) and on curly mustard (Brassica pervirdis L.). Ammonium nitrate produced greater increases in NO3‐N and total N concentrations in chard than did sulfur‐coated urea at the same rates of applied N. Both N and K increased yields and NO3‐N accumulation in spinach and mustard; response to applied P resulted only in decreased NO3‐N. Both total and NO3‐N concentrations decreased with dilution and/or assimilation associated with time of growth and higher yields. An examination of published results with several spinach cultivars indicates that differences in NO3‐N accumulation attributed to leaf type can also be explained by the higher yields of the low NO3‐N accumulators. The same is true for differences in NO3‐N accumulations attributed to light and temperature effects.

AbstractThree greenhouse pot experiments were conducted with corn (Zea mays L.) grown on infertile soils to evaluate four fertilizers as sources of P. The granular sources were concentrated superphosphate (CSP, 90% of P water‐soluble), monoammonium phosphate (MAP, 100% of P water‐soluble), a mixture of 30% of the P as CSP and 70% as dicalcium phosphate (DCP, water‐insoluble), and a 10‐90% mixture of CSP and DCP. Rates of 0, 50, 200, 400, and 800 mg of P/pot from each source were compared in Exp. 1; and 0, 60, 120, and 480 mg rates of P in Exp. 2 and 3. These P sources and rates were compared at various levels of N and K. The order of effectiveness was the same at all levels of applied N and K: MAP ≥ CSP > 30% CSP + 70% DCP > 10% CSP + 90% DCP. This indicates that on these soils, P was the chief limiting nutrient at all levels of N and K. However, yield levels and the precision of determining differences in effectiveness among sources relative to experimental error increased greatly at higher rates of applied N and K.These results show that effectiveness of P sources and also source differences relative to experimental error are greater at adequate than at deficient levels of nontest nutrients or other growth‐limiting factors. Adequate levels of nutrients for greenhouse pot experiments are much higher per pot equivalent than the normal recommended application rates for crops grown under field conditions.

AbstractFluidized bed boilers for steam electric power plants have been developed recently to improve efficiency and to utilize coal and a wide range of other fuels. The fluidized bed waste (FBW) generated by these boilers is expected to reach large volumes as new plants are built. It is an anhydrous waste containing substantial amounts of CaSO4 and unreacted CaO. Since no previous agronomic evaluation of FBW has been reported, greenhouse pot experiments were carried out.At moderate rates of application, FBW is satisfactory as a source of sulfur for crops and as a soil liming material. High disposal rates of new waste initially restrict crop growth, apparently because of high alkalinity resulting from the high oxide content of the FBW. On acid Mountview sil, fine (< 0.1 mm) FBW was 47% as effective as fine CaCO3 over a 5‐week period for increasing soil pH. Coarse (< 3.4 mm) FBW was only 8% as effective as fine CaCO3, because of less reactivity apparently resulting from its granular nature and CaSO4 coatings on the granules. On pyritic coal mine spoil, lower liming rates did not affect spoil pH, but at higher rates coarse FBW was 44% as effective as fine CaCO3 for increasing spoil pH over a 10‐month period.

Agronomy JournalVolume 70, Issue 3 p. 519-520 Letter to the Editor Comments on Significant Figures in Relation to Experimental Errors G. L. Terman, G. L. TermanSearch for more papers by this author G. L. Terman, G. L. TermanSearch for more papers by this author First published: 01 May 1978 https://doi.org/10.2134/agronj1978.00021962007000030043xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume70, Issue3May‐June 1978Pages 519-520 RelatedInformation

Total N, P, K, Ca, and Mg concentrations were determined in corn (Zea mays L.) and in southern pine seedlings (Pinus sp) grown in N, P, and K response experiments in greenhouse pots. Analyses of variance were made for dry matter yields, for nutrient concentrations, and for nutrient uptake determined for individual pots and calculated as percent nutrient of composite samples times individual pot dry matter. Compositing replicate plant samples gave satisfactory uptake values and usually gave similar or lower coefficients of variability (CV) than did uptake determined by individual pots. Amounts of each replicate sample composited should be in proportion to the respective dry matter yields to avoid bias in concentration and uptake values. Such compositing, together with accurate analytical methods, can greatly reduce the analytical work load and produce satisfactory research results.

AbstractThis study was undertaken in an attempt to quantify relationships among anions (An) and cations (Cat) leached from soils. Several sets of published data on leaching of ions from acid and nonacid soils were evaluated by linear regression calculations based on the chemical equivalency of Σ Cat and Σ An leached. Calcium, Mg, K, and Na comprised most of Σ Cat, and NO3, SO4, and Cl, most of Σ An. Bicarbonate (HCO3) is also leached from nonacid soils; H is assumed to account for most of the excess of Σ An over Σ Cat in leachates from acid soils. The regression coefficient for each cation on Σ An indicates its contribution to anion leaching and that for each anion on Σ Cat indicates its contribution to cation leaching. Amounts of each ion leached from a given soil depended largely on amount of soluble ion present and amounts of leachate. Calcium and NO3 tended to dominate Σ An and Σ Cat leached if these ions were applied or were abundantly present in a soil. Magnesium, Na, SO4, and Cl were increasingly important as the proportionate supply of each increased. Potassium was not leached in amounts appreciable enough to influence amounts of anions lost, and HCO3, although present in appreciable amounts in nonacid soils, apparently was not related to Σ Cat leached. Amounts of ions leached were much more closely correlated with leachate volumes among soils and time periods than with leachate volumes from various treatments for a given time period.

AbstractThree greenhouse pot experiments with corn (Zea mays L.) were conducted to study effects of multiple rates of applied N, P, and K on growth and yield—nutrient concentration trends. Harvests were made each 4 or 6 days from 15 to 56 days after plant emergence. Growth and plant nutrient concentrations and uptake increased with rate of each applied nutrient at adequate levels of other nutrients. Applied N also increased both P concentrations and uptake in young corn plants. Yield response to applied K resulted only in dilution of N and P concentrations at even the earliest harvest. Concentrations of all nutrients were soon diluted to lower levels with increase in dry matter and/or age of plants, so that comparative results varied with time of harvest. Growth rates increased with adequacy of nutrient supply and more favorable growth conditions; they declined greatly soon after depletion of applied N. The limited soil volume in pot experiments, rate of growth, and time of harvest all greatly influence the effects of one nutrient on plant concentrations of other nutrients.

AbstractMost published results with southern determinate soybeans [Glycine max (L.) Merr.] are concerned with only a single fertilizer treatment and/or one or two sampling dates. Consequently, field experiments were conducted to determine effects of applied N and K on dry matter yields, nutrient concentrations, and nutrient uptake at several sampling dates and on final grain yields. Rates of 0, 86, and 172 kg of applied K/ha and 0 and 70 kg of N were compared in a field experiment on Sango sil (Ochrepic Fragiudult) in 1973 and K rates of 0, 75, and 150 kg/ha in 1974.Marked responses to applied K were obtained. Maximum dry matter yields and nutrient uptake occurred during the early pod filling stage of growth. Dry matter yields then declined as a result of greater loss of leaf and petiole drop than of increase in grain filling. Concentrations of K in leaves, topgrowth, and grain increased with amount of applied K, but top trifoliate leaf blade concentrations were lower than some published recommended levels for high yields. Marked reciprocal relationships occurred among concentrations of K and Ca or Mg in top trifoliate leaves and topgrowth.Several combinations of N, P, K, and S foliar‐ and soil‐applied during pod filling were also compared in a 1976 pot experiment on Sango sil. Grain yields and concentrations of each applied nutrient were increased in leaves and grain. Pod numbers were highly correlated with grain yields.

AbstractWidely varying results and conclusions are reported in the literature concerning the effects of environmental growth factors, especially temperature, on yields of dry matter and nutrient absorption by plants. The purpose of this paper is thus to evaluate the effects of temperature in three greenhouse pot experiments and as reported in the literature on yield‐nutrient uptake relationships. Several rates of applied N and P were compared in Exp. 1 for oats (Avena sativa L.) grown for 7 weeks at three combinations of day length and temperature. Several rates of N and P in factorial combination were compared in Exp. 2 for corn (Zea mays L.) grown for 4 weeks at water bath temperatures of 16 and 27 C. Corn was also grown in Exp. 3 for 3 and 6 weeks to compare P rates and temperatures of 16 and 21 C and at ambient temperatures (25 to 35 C). Dry matter yields and uptake of N and P (also of cations in Exp. 3) were determined. Plant nutrient concentrations, especially of P, increase with higher soil temperatures in experiments of short duration and with little yield response to temperature. However, with marked yield response, dilution of plant nutrient concentrations but higher uptake are the dominant trends with increase in temperature up to the optimum for each crop species. The reverse usually occurs at temperatures above the optimum. Release of nutrients from the substrate with higher temperatures varies greatly with soil fertility level and amounts of applied nutrients. Rate of root growth is also very likely a predominant factor in plant uptake of nutrients, especially those having limited mobility in the soil.

AbstractAccumulation of NO3‐N in plants is important in regard to plant N nutritional status, in the formation of NO2‐N toxic to animals and people consuming the plants, and as a producer of lethal gas in silos. This paper describes relationships between NO3‐N and total N concentrations in plants grown in several greenhouse pot experiments, as affected largely by response to applied N and by continuing growth. Corn (Zea mays L.) was grown in soil with 200 to 800 mg of N/pot and in nutrient solutions with 2 to 16 ppm of N. Both crops were harvested at 4‐day intervals. Spinach (Spinacea oleracea L.) and mustard (Brassica pervirdis L.) were grown in soil with several rates of N, P, and K, and tall fescue (Festuca arundinacea Shreb.) with 1.0 and 2.0 g of N/pot.These experiments conducted on N‐deficient soils resulted in marked yield response and higher concentrations of total N and NO3‐N with increase in rates of applied N. Concentrations decreased with age, dry matter accumulation, and depletion of N. Total N was higher in leaves than in stems, but the reverse was true for NO3‐N. Concentrations of NO3‐N started to increase in various crops above minimum total N values of 1.5 to 4.5%, which were highest for leaves, intermediate for leaves + stems, and lowest for stems or petioles. Below these minimum total N values, NO3‐N remained near zero (< 0.1%). Discontinuous regression models appear most satisfactory to fit the entire range of the relationships between total and NO3‐N. It was concluded that NO3‐N concentrations in plants are negligible if the total N was < 1.5% to 4.5%, depending largely on plant part composition, plant species, and N source.

Agronomy JournalVolume 68, Issue 1 p. 148-150 Letter to the Editor Comments on Use of Multiple Regression in Plant Analysis Interpretation G.L. Terman, G.L. TermanSearch for more papers by this authorL.A. Nelson, L.A. NelsonSearch for more papers by this author G.L. Terman, G.L. TermanSearch for more papers by this authorL.A. Nelson, L.A. NelsonSearch for more papers by this author First published: 01 January 1976 https://doi.org/10.2134/agronj1976.00021962006800010042xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume68, Issue1January-February 1976Pages 148-150 RelatedInformation

Greenhouse pot experiments were conducted to compare responses of corn ( Zea mays L.) and snap beans ( Phaseolus vulgaris L.) to 0 to 1,600 mg of K/pot as KNO 3 , KCl, and K 2 SO 4 on K‐deficient soils (3 kg of soil/pot). Marked responses were obtained to applied K, which were similar among sources, except for a toxic salt effect of 1,600 mg of K as KCl. Marked reciprocal K‐N, K‐P, K‐Ca, and K‐Mg relationships with yield response to rates of applied K were attributed to both dilution and ion antagonism. The latter was most pronounced at higher K rates giving little or no additional yield response and resulting in decreased Ca, Mg, or P uptake. There was a close relationship between total N and total cation concentrations in corn leaves but not in bean leaves. This difference is attributed to absorption of much of the N as NO 3 ‐N by corn and as biologically fixed NH 2 ‐N by snap beans.

AbstractResearchers have concluded in several published papers that differences in nutrient absorption among crop cultivars are genetically controlled. However, growth rate and yield differences among cultivars were not usually evaluated. The present investigation involved three greenhouse experiments conducted to study relationships between yield levels and concentrations of P, Mn, and Zn in several corn hybrids (Zea mays L.) during early growth. Eight hybrids were grown with 0, 1, 2, and 4 ppm of Zn in factorial combination with 17 and 167 ppm of P; five hybrids with 0 and 3.4 ppm of Zn and 0, 233, 466, and 932 ppm of P; and three hybrids with 0, 11, 33, 90, 180, and 360 ppm of P. Other nutrients were applied uniformly. Top growth was harvested after 6 to 11 weeks, dried, and analyzed for total P, Mn, and Zn.Results from these experiments, together with published data, show that concentrations of P, Mn, and Zn among hybrids at each application rate decreased markedly with increasing yields. Higher yields resulting from more rapid growth following a 2‐week delay in planting one hybrid also greatly reduced P concentrations in the plants. Thus, nutrient concentrations and uptake in various corn hybrids, at least during early growth, need to be evaluated in terms of growth rates, total dry matter or final grain yields, and planting and maturity dates. Differences in nutrient absorption among corn hybrids appear to be greatly influenced through genetic effects on growth rates and yield potentials. Plots of yields vs. nutrient concentrations or uptake are useful to determine differences among hybrids at the same yield levels.