bluuebunny/crossref_metadata_2025 huggingface dataset:
Relation of Fertilizer Placement to Nutrient Uptake and Crop Yield: II. Effects of Row Potassium, Potassium Soil‐Level, and Precipitation1
Authors: Barber Stanley A.
Published: July 2010

Synopsis

Both potassium soil‐level and row potassium treatments were about equally effective in supplying potassium for a corn‐soybean‐wheat‐hay rotation. Relative increases in corn and soybean yields due to potassium fertilization were inversely correlated with the amount of rainfall which occurred during the growing season.
Terrace Benching to Save Potential Runoff for Semiarid Land1
Authors: Zingg A. W. , Hauser V. L.
Published: July 2010

Synopsis

Limited tests show that the practice has promise for moisture‐deficient areas. First year's results indicate that the system is capable of retaining a sufficient portion of storm runoff to materially increase crop yield.
Crop Response to Zinc Fertilization as Influenced by Lime and Phosphorus Applications1
Authors: Seatz Lloyd F. , Sterges Athan J. , Kramer James C.
Published: July 2010

Synopsis

Response of flax and sorghum to zinc fertilization increased as the liming rate was increased from 2 to 6 tons of CaCO3 per 2 million pounds of Hartsells soil. Phosphorus fertilization did not affect zinc response. Best growth was obtained when the Ca/Mg ratio of the liming material as 2/1.
Cytoplasmic Effects on Agronomic Characters in a Double‐Cross Maize Hybrid1
Authors: Fleming A. A. , Kozelnicky G. M. , Browne E. B.
Published: July 2010

Synopsis

Significant cytoplasmic effects were obtained in a double‐cross maize hybrid for the agronomic characters: yield, silking, ear and plant heights, erect plants, and budworm damage. All cytoplasms did not interact with the genotype in the same manner. These results apparently justify consideration of the source of cytoplasm in a breeding program. In most cases when differences occurred between the cytoplasmic effects, the performance of the hybrid was in the direction of the inbred performance.
Effect of Soil Moisture Level on Root Distribution of Cool‐Season Forage Species1
Authors: Bennett Orus L. , Doss Basil D.
Published: July 2010

Synopsis

Effective rooting depth decreased as soil moisture level increased. A high percentage of the roots was found in the surface 12 inches of soil for all species regardless of soil moisture level. Soil moisture extraction was used with reasonable accuracy to estimate effective rooting depth.
Effect of Black Polyethylene Mulch on Soil and Microclimate Temperature and Nitrate Level
Authors: Clarkson V. A
Published: July 2010

Synopsis

At various depths under the mulch, maximum daily temperatures were somewhat higher and minimum temperatures somewhat lower. No harmful effects on plants were noted. Under mulch the movement and leaching of nitrates were reduced and utilization by corn was increased.
The Effect of Seeding Rate and Rate of Nitrogen Application on Winter Wheat Varieties with Different Characteristics1
Authors: Pendleton J. W. , Dungan G. H.
Published: July 2010

Synopsis

Varieties showed a different yield response to seeding rates and to rates of nitrogen application. This response did not seem to be correlated with varietal morphological characteristics. Variety selection controlled more agronomic characteristics than either rate of nitrogen application or rate of seeding.
Sediment Delivery Ratio Studies in Mississippi. I. A Preliminary Report1
Authors: Spraberry James A. , Woodburn Russell , McHenry J. Roger
Published: July 2010

Synopsis

Computed gross erosion for a number of north Mississippi watersheds was compared with the measured sediment yields. The computed sediment delivery percentages varied greatly for the different watersheds but these differences were not correlated with any measured physical parameter of the watersheds.
Evaluation of Semidwarf Selections from a Spring Wheat Breeding Program1
Authors: Mcneal F. H. , Berg M. A. , Klages M. G.
Published: July 2010

Synopsis

Semidwarf selections averaged 5 to 9 inches shorter than standard varieties, depending on location of the planting. Yields and test weights were essentially equal, indicating that high yielding, short‐straw spring wheats can be produced. The shortness of the semidwarfs is due chiefly to shorter peduncles but the other internodes also are shorter. Both types responded similarly to nitrogen fertilizer, but the standard varied more in plant height than the semidwarf.
Development and Composition of Spring Wheat as Influenced by Nitrogen and Phosphorus Fertilization1
Authors: Boatwright G. O. , Haas H. J.
Published: July 2010

Synopsis

Dry matter production and N uptake by wheat reached a maximum at heading, soft dough, and maturity on NP, N, and unfertilized plots, respectively. Maximum P uptake occurred by heading irrespective of treatment. Nitrogen and phosphorus in the grain were derived primarily by translocation from leaves, stems, and chaff, and the amount was influenced by fertilization.
Legume Establishments as Related to the Presence or Absence of an Oat Companion Crop1
Authors: Peters Robert A.
Published: July 2010

Synopsis

When measured at the time the oats were removed for silage, legume yields were lowest when seeded with oats. Recovery during a favorable year (1959) was rapid for alfalfa, red clover, and Ladino clover. Yields of birdsfoot trefoil remained depressed. During a dry year (1957) alfalfa regrowth was satisfactory following seeding competition with weeds but not with oats. It was concluded that oats frequently will be much more competitive than the weed growth which will flourish in their absence.
Extraction of Soil Moisture by Merion Bluegrass (Poa pratensis L. ‘Merion’) Turf, as Affected by Irrigation Frequency, Mowing Height, and Other Cultural Operations1
Authors: Madison John H. , Hagan Robert M.
Published: July 2010

Synopsis

Height of cut, irrigation frequency, and aeration treatments all produced significant differences in water extraction. Extraction by 3‐ and 4‐year‐old sod occurred almost entirely in the top 20 inches of the soil.
Some Observations on the Movement of Water to Plant Roots1
Authors: Gardner W. R. , Ehlig C. F.
Published: July 2010

Synopsis

An equation describing the uptake of water by plants is described. Greenhouse experiments support the equation and show that the lower limit of water availability is determined by the rate of water transmission through the soil to the plant roots. An appreciable amount of water is shown to move vertically in the root zone.
Growth of Ryegrass as Influenced by Temperature and Solar Radiation1
Authors: Weihing Ralph M.
Published: July 2010

Synopsis

Simple correlation was 0.84 between growth and daily mean temperature within the range of 47° to 67° F. It was 0.74 between growth and daily mean solar radiation within the range of 214 and 491 langleys. Several multiple regressions of growth on various expressions of temperature and solar radiation were studied. The equation Ŷ = −495.72 + 17.0285x1 − 0.1306x2, where X1 = temperature and x2 = temperature2, appeared best suited for predicting growth rates of forage in ryegrass pastures.
Selenium Uptake and Conversion by Certain Crop Plants1
Authors: Hamilton J. W. , Beath O. A.
Published: July 2010

Synopsis

All plants studied possess the ability to absorb selenium from the soil. This selenium is metabolized and stored in the plant tissue in sufficient quantities to render the plant material capable of producing toxic effects when eaten by animals. All plants and, in some instances, their seeds or grains contained both organic and inorganic selenium. Flaxseed, safflower seed, and the root portion of sugar beets contained relatively low levels. Sunflower plants possessed the highest selenium‐absorbing ability.
Effects of Iron Chelates and Nitrogen on Safflower and Flax Seed Production and Oil Content and Quality1
Authors: Yermanos D. M. , Hall B. J. , Burge W.
Published: July 2010

Synopsis

Eight iron chelate formulations applied on field plots of flax and safflower did not increase seed yields. Seed oil content and iodine value of oil were not affected except in one case when an increase in iodine value was associated with a decrease in seed yield. Nitrogen fertilization depressed iodine value of oil and seed oil content but increased seed yields.
Influence of Cultural Treatments on Seed Production of Intermediate Wheatgrass (Agropyron intermedium (Host) Beauv.)1
Authors: Canode C. L.
Published: July 2010

Synopsis

Burning of the straw and stubble after harvest was beneficial in maintaining high seed yields of intermediate wheatgrass. Mechanical removal of every other foot of vegetation in the row produced seed yields equal to burning. The effects of burning and mechanical thinning appeared to be additive. Increasing the rate of nitrogen was not effective in maintaining seed production as the stands became older.
Forage Production of Red Clover and Alfalfa Under Differential Cutting1
Authors: Smith Dale
Published: July 2010

Synopsis

Red clover produced yields equal to alfalfa only when harvested under the conservative 2‐cutting schedule. Alfalfa yields were highest with 3 harvests at early bloom. Autumnal yields were small, and early October cutting reduced subsequent yields and stands.
Soil Components Determining Bensulide Phytotoxicity
Authors: Lynd J. Q. , Rieck C. E. , Santelmann P. W.
Published: July 2010

Organic matter amendment, soil reaction and cation exchange capacity interactions with Eufaula sand and Brewer clay loam were determined for bensulide, S‐(O, O‐diisopropyl phosphorodithioate) of N‐(2‐mercaptoethyl) benezenesulfonamide. Herbicidal effectiveness for crabgrass growth was reduced with ground straw and mimosa soil additions. Acid soil reactions reduced bensulide activity on both soil types. Reduced phytotoxicity occurred with increased soil cation exchange capacities in Eufaula‐Brewer soil mixtures.
Incidence of Smut at Three Corn Plant Populations1
Authors: Rutger J. N. , Risius M. L.
Published: July 2010

Average smut infection of a group of 30 corn hybrids tested in 5 locations increased as plant populations were increased from 20,800 to 29,200 plants per acre. A highly significant (1% level) hybrid × population interaction for incidence of smut indicated that hybrids respond differentially to planting rates.

Although most of the hybrids were believed to be relatively tolerant to smut, highly significant hybrid differences in infection were observed. Smut infection, averaged over locations and populations, ranged from a low of 2.9% for hybrid 16 to a high of 18.3% for hybrid 26.
Nitrate Accumulations in Forage Crops1
Authors: Murphy L. S. , Smith G. E.
Published: July 2010

The effects of N and P fertilization rates and stage of plant maturity on the nitrate‐N content of nine forage species were studied over a 2‐year period. Species included in the investigations were orchardgrass, tall fescue, bromegrass, bluegrass, timothy, sudangrass, wheat, alfalfa, and ladino clover. Nitrate‐N was determined on hot water extracts of dried plant material by the phenoldisulfonic acid method.

Of the species under study, sudangrass accumulated nitrate‐N to the greatest extent. It was closely followed by orchardgrass and fescue. Bromegrass, timothy, and ladino clover accumulated intermediate amounts of nitrate‐N. Alfalfa and wheat accumulated little of this form of nitrogen.

Increased N fertilization had a direct effect on nitrate‐N accumulation. Phosphorus fertilization had little if any effect upon the nitrate‐N contents of the various species.

Advancing plant maturity was associated with a decline in the nitrate‐N content of most species.
Performance of Four Pasture Mixtures Defoliated by Mowing or Grazing with Cattle or Sheep1
Authors: Matches Arthur G.
Published: July 2010

Evaluation of pasture mixtures in small‐plot clipping trials may be criticized since plant responses after mowing may not be the same as those after grazing. In this investigation, four pasture mixtures (tall fescue‐ladino clover, orchardgrass‐ladino clover, smooth bromegrass‐alfalfa, and Kentucky bluegrass‐birdsfoot trefoil) were evaluated under mower, sheep, and cattle defoliation. Only yields of orchardgrass‐ladino clover were significantly influenced by method of defoliation; and a significant defoliation method ✕ mixture interaction was due largely to the response of this mixture. Yields of orchardgrass‐ladino clover under mowing were significantly less than yields under animal defoliation. Botanical composition of the bromegrass‐alfalfa and bluegrass‐trefoil mixtures did not appear to be influenced by method of defoliation. Stands of ladino clover were lost early in the investigation. Tall fescue and orchardgrass appeared to be more competitive with weeds under cattle defoliation than when defoliated by mowing or grazing with sheep. Yield rankings of the four pasture mixtures were similar within the three methods of defoliation. It appears that herbage yields obtained in small plot clipping trials are reliable for predicting performance of forages under grazing conditions.
Effect of Gaseous Composition of Root Environment upon Root Development and Growth of Nicotiana tabacum L.1
Authors: Williamson R. E. , Splinter W. E.
Published: July 2010

Tobacco gaseous treatments

The extent of root and shoot injury of tobacco plants exposed to various gaseous treatments (O2, CO2, N2) in the root environment was determined by microscopic examination of roots, stem diameter changes, and shoot measurements. An attempt was also made to determine the relative importance of O2 deficiency and CO2 excess in causing the observed injury. The plants were grown in an environmental control chamber with roots in an intermittent solution mist in airtight chambers.

Oxygen levels of 2.5%, with and without 18.5% CO2, the remainder being N2, caused no apparent reduction in root or shoot growth. One percent O2 plus 99% N2 treatments for 24 or 48 hours reduced the rate of growth during treatment; but the plants resumed a normal rate of growth during recovery. One percent O2 plus 20% CO2 plus 79% N2 treatments for 24 or 48 hours caused death of several root tips, chlorosis of the lower leaves, necrotic areas on some other leaves, and considerable reduction in the rate of growth during treatment. Treatments with pure N2 for 12 hours caused growth to cease for 60 hours. Treatments with pure N2 for 24 hours resulted in death of the root system within 4 days. Treatments with 21% CO2 for 24 hours killed the plants more quickly than did pure N2.
Influence of Precipitation, Soil Water, and Plant Population Interactions on Corn Grain Yields1
Authors: Holt R. F. , Timmons D. R.
Published: July 2010

Corn grain yield response to different levels of soil water, precipitation, and plant population during the rapid growth period of corn was evaluated by multiple regression using 4 years' field data. For 17 locations showing a yield response to stand, multiple regression accounted for 91% of the variation in grain yields during the 4‐year period. Estimated corn yields from the developed equation varied from 0 to 8976 kg/ha for all possible combinations of the independent factors.

The corn growth interval from 30‐cm plant height to silking was divided into two equal time periods. Precipitation received during the second period (late July and early August) exerted a greater influence on corn yields than did that received during the first period (early July). With increased precipitation during the two periods, the optimum part of the stand—yield curve shifted to correspondingly higher stands.
Zinc Nutrition of Alfalfa1
Authors: Lo Shitao Yie , Reisenauer H. M.
Published: July 2010

The influence of Zn supply on the yield and chemical composition of alfalfa grown with symbiotically fixed N or with nitrate N under conditions that provided relatively rapid or slow growth rates is reported. Nitrogen source had no effect on the relationship between relative yield and the concentration of Zn in the leaf tissues confirming the earlier conclusion that symbiotic N fixation is only indirectly influenced by the Zn nutrition of the host plant. Rate of growth influenced the level of Zn in the nutrient media required for maximum yield but did not affect the leaf Zn concentration associated with maximum production. Top yields were obtained with leaf Zn levels greater than 6 ppm. This value is approximately one‐third to one‐half that required for most other crops and explains the infrequent response of alfalfa to Zn fertilization.

Observations and analyses of field grown alfalfa revealed no unusual ability of the crop to absorb or accumulate soil Zn and failed to explain the reported beneficial influences of alfalfa on the Zn nutrition of associated crops.
Method for Predicting Potassium Uptake by Grain Sorghum1
Authors: Hipp Billy W. , Thomas Grant W.
Published: July 2010

A greenhouse experiment using nutrient solution culture with graded levels of K was used to determine the concentration of K required in grain sorghum leaves for optimum growth. It was determined that growth of grain sorghum is reduced if the leaf K concentration is much below 1.5% at the full bloom stage. A field study was made to relate soil K parameters from eight different soils to concentration of K in grain sorghum leaves at the full bloom stage of growth. The best method of predicting K uptake by plants included both solution K and exchangeable K. A correlation coefficient of 0.890 was obtained between percent K in leaves and solution K + log (1 + exchangeable K).
Capillary Conductivity and Soil Water Diffusivity Values from Vertical Soil Columns1
Authors: Flocker W. J. , Yamaguchi M. , Nielsen D. R.
Published: July 2010

Water evaporated from vertical columns of Yolo loam, 100 cm long, for 200 days at ambient temperatures of 10, 20, or 30C ± 1C. Distribution of soil water was determined by gamma‐ray attenuation at 5‐cm intervals, concomitantly with determinations of soil water pressure. Values of capillary conductivity based upon measured fluxes and hydraulic gradients are presented, along with values of diffusivity based upon fluxes and water content gradients.
Effect of Drying Methods on Losses of Carbon, Nitrogen and Dry Matter from Alfalfa1
Authors: Mayland H. F.
Published: July 2010

Methods of drying forage samples were examined for their influence on the total C, N, and dry matter (DM) content of ‘Ranger’ alfalfa (Medicago sativa L.). Forage samples were freeze‐dried; air‐dried in perforated paper bags and on trays; dried in perforated paper bags in mechanical convection ovens at 60, 80, and 100 C; and oven‐dried at 100 C for 90 minutes followed by drying at 60 C, or by air‐drying. All treatments were terminated after 48 hours.

Losses in C and N were measured by changes in C:K and N:K ratios. The DM losses were measured by changes in K concentration. Carbon and DM were lost more readily than N by either respiratory or thermochemical processes. These losses resulted in an apparent concentration of N in all forage dried between ambient and 100 C. All treatments, when compared to freeze‐drying, resulted in losses of C and DM. The greatest loss of DM, 5.4% occurred in samples dried at 100 C. Oven‐drying at 100 C for 90 minutes followed by air‐drying caused IDM losses of only 0.2%. Significant differences in actual N content between the various drying methods were not generally observed.
Determinants of Pasture Value of Phalaris arundinacea L. vs. Bromus inermis Leyss.1
Authors: Marten G. C. , Donker J. D.
Published: July 2010

The objectives of this study were to determine the influence of the apparent lack of palatability of reed canarygrass on performance of grazing dairy animals and to compare quality and yielding ability of smooth bromegrass vs. reed canarygrass through measurement of gains per animal and gains per hectare when the two grasses were grazed alone under two grazing pressures.

In a preliminary pasture palatability trial, dairy heifers showed a distinct preference for brome over reed canary. A 4−year pasture production study revealed, however, that average daily gains of heifers restricted to rotational grazing within only brome or reed canary did not differ (0.74 kg for each). Also reed canary produced 20% more heifer gain per hectare than brome due to greater carrying capacity.

The heavier grazing pressure caused a slight but significant reduction in average daily gains per heifer, but it resulted in increases in heifer gain per hectare over the lighter grazing pressure (19% for reed canary and 16% for brome).

The preference of heifers for brome over reed canary was of little or no practical significance when the two grasses were grazed individually without choice. Reed canary was obviously higher yielding and more persistent than brome, and these traits merit recommendation of reed canary for pasture situations in which a pure stand of grass on upland mineral soil is desired.
Comparative Elemental Analyses of Plant Tissue by Spark Emission and Atomic Absorption Spectroscopy
Authors: Jones J. Benton , Isaac Robert A.
Published: July 2010

The analyses of 91 plant tissues for their A1, Ca, Cu, Fe, K, Mg, Mn, and Zn content by direct reading emission and atomic absorption spectroscopy were comparable for most elements. Statistically significant differences were obtained for the elements K and Mg although the numerical differences were small. The variances within each laboratory were sufficiently large for A1, Ca, Cu, Fe, Mn, and Zn to mask significant differences between laboratories. Discrepancies between laboratories were observed in several plant specie samples for the elements AI, Cu, and Fe. Reproducibility by atomic absorption was better than that obtained by emission spectroscopy except for the elements A1 and Cu. Although some differences were found for certain elements and plant tissue samples, the analytical results compared favorably between the methods and laboratories.
Aluminum Tolerance of Soybean Varieties in Relation to Calcium Nutrition1
Authors: Foy C. D. , Fleming A. L. , Armiger W. H.
Published: July 2010

Differential aluminum tolerance of ‘Perry’ and ‘Chief’ soybean varieties, determined previously from growth on acid Bladen soil, was confirmed in nutrient solutions containing Al as the known growth‐limiting factor. Differences in Al tolerance between the two varieties were steadily increased as the Ca level of the nutrient solution was reduced from 50 to 8 to 2 ppm.

Aluminum toxicity in soybeans was associated with decreases in concentrations of Ca in the tops and roots of both varieties, but this effect of Al was much more pronounced in the Al‐sensitive Chief variety than in the more tolerant Perry. Greater Al sensitivity of the Chief variety was associated with greater susceptibility to a petiole collapse symptom. This symptom was related to a lower Ca concentration in the leaves and petioles, and specifically, related to a lower Ca concentration in the small petiole zone actually showing the collapse. Soil and solution studies indicated that the Ca deficiency observed in acid Bladen soil was Al induced. Aluminum appears to interfere to different degrees in the uptake and use of Ca by these two soybean varieties. The petiole collapse appeared to be a secondary effect of Al injury, and the presence of the symptom was not required for yield reduction by Al. The fact that soybean varieties differ in Al tolerance suggests that plant breeders may be able to develop varieties that can root more effectively in acid, Al‐toxic subsoils. Varieties differing in Al tolerance also provide valuable tools for fundamental studies on the physiological nature of Al toxicity in plants. The petiole collapse symptom associated with Al sensitivity may be useful to plant breeders in screening genetic populations of soybeans for Al tolerance.
Differential Tolerance of Cotton Varieties to Excess Manganese
Authors: Foy C. D. , Fleming A. L. , Armiger W. H.
Published: July 2010

Cotton varieties adapted to various regions of the Cotton Belt of the United States showed differential leaf crinkling symptoms and growth in greenhouse pots of acid Manteo soil (pH 4.5) from Orange, Va, Subsequent experiments with soils and nutrient solutions containing variable Mn confirmed the hypothesis that the plant symptoms were due to Mn toxicity; however, other evidence indicated that Al toxicity was more important than Mn toxicity in limiting growth.

Cotton varieties showing the greatest tolerance to excess Mn in soils or nutrient solutions were ‘Rex Smooth Leaf’ (Arkansas), ‘Acala 1517D’ (New Mexico), and ‘Gregg’ (Texas). Varieties showing the least tolerance were ‘Acala 4‐42’ (California) and ‘Coker 100A’ (South Carolina). Tolerance of some varieties was attributed to the fact that they or their ancestors were developed on high‐Mn soils. Greater Mn tolerance of the Rex Smooth Leaf variety appears to be due not to reduced Mn uptake but to a greater ability to tolerate a high level of Mn in its tops. Cotton varieties having greatest tolerance to Mn were not necessarily those showing greatest tolerance to Al in a previous study.
Comparison of Sulphate of Ammonia and Slow‐Release Nitrogen Fertilizers for Rice in Trinidad
Authors: Ahmad N. , Whiteman P. T. S.
Published: July 2010

Two slow‐release pelletted N fertilizers manufactured by Esso Engineering and Research Ltd. known as EAP 3032 (17.7% N, 21 days to release 75%) and EAP 3033 (18% N, 63 days to release 75%) were compared with (NH4)2SO4 as sources of nitrogen for the rice variety ‘Bluebelle’ in Trinidad. Nitrogen dressing from all sources was 70 kg/ha applied at transplanting. The slow release materials were buried 5 cm into the soil after transplanting while the (NH4)2SO4 was applied and cultivated into the soil just before transplanting. The effect of these treatments on yield, growth, and N uptake was estimated. EAP 3033 resulted in increased yield of 2,920 kg/ha; EAP 3032, 2,060 kg/ha; and (NH4)2SO4, 1,195 kg/ha. The response was made up by small increases in all yield components but especially panicle weight resulting from more spikelets per panicle and a higher percentage of filled grains. The fertilizers reduced the response to a top dressing of N applied 35 days after transplanting, especially the EAP 3033 treatment. The pattern of N recovery by the crop was closely related to the release of N from the fertilizers. Plants treated with (NH4)2SO4 had absorbed all of their N when they had accumulated only 50% of final dry weight. At the same stage plants treated with slow‐release materials had absorbed only half of their final N content and they continued to absorb N to much later stages in growth.
An Improved Monolith Method for Excavating and Describing Roots
Authors: Nelson W. W. , Allmaras R. R.
Published: July 2010

A root sampling frame was constructed to excavate roots in a soil monolith 152 by 41 by 91 cm in height. The frame and monolith were moved by farm hydraulic equipment. Access to the soil monolith was provided wtih a 10‐cm‐wide trench. The total proliferation attributable to four corn (Zea mays) plants was included in the sample, permitting more precise evaluation of horizontal and vertical root proliferation. Pin insertion into the monolith and later removal after washing, and before photography of submerged roots, permitted a better quality description of root proliferation.

Corn root samples obtained 39 days after planting and application of three straw mulch treatments (about 31 days after emergence) revealed significantly different patterns of root proliferation horizontally and vertically. The relative difference of root growth was greater than that of the shoot, and shoot/root ratios varied from 1.3 to 3.1.
Influence of Submerged Soil Temperature Regimes on Growth, Yield, and Nutrient Composition of Rice Plant1
Authors: Chaudhary T. N. , Ghildyal B. P.
Published: July 2010

Rice plants of a Taiwanese indica variety, ‘Taichnng (Native) 1,’ were grown in a clay loam soil for 6 weeks from seeding under normal conditions of a greenhouse and then transferred to controlled temperature water baths where cyclic soil temperatures were maintained till harvest. Water level was maintained at a depth of 5 to 7 cm above the soil surface. The temperature cycles as characterised by their maxima and minima were 22/10, 27/I5, 32/20, 37/25 and 42C/30C. The experiment was first conducted during winter months and repeated during summer months except that 22C/10C cycle was not included.

Soil temperature greatly influenced vegetative and reproductive growth of the plant. Nearly similar effects of different soil temperature regimes were observed during winter and summer although the difference of about 11 or 12C in aerial temperatures existed. Highest grain yield was obtained at 32C/20C which resulted from larger number of tillers, panicles, and spikelets, lower spikelet sterility and greater hundred grain weight than at lower and higher temperatures. A dose correspondence was observed between root and shoot growth. Greater uptake of nutrients was associated with larger root system. There was a tendency for grain to be higher and straw to be lower in N, P and K concentration at 32C/20C than at lower and higher temperatures. NPK content of the grain was significantly correlated with grain yield.

The direct effects of soil and water temperature on shoot growth were also probable since tiller and panicle primordia develop at the basal portion of the stems which remained submerged under soil‐water.
Effect of Potassium on the Mineral Constituents of Pearl Millet and Sudangrass1
Authors: Schneider B. A. , Clark N. A.
Published: July 2010

The effect of K at O and 672 kg/ha and various combinations of Ca, Mg, and K on the nitrate‐N content of pearl millet [Pennisetum typhoides (Burm.) Staph and Hubbard] and sudangrass [Sorghum sudanense (Piper) Staph] was studied. Nitrogen and P were added uniformly on all plots. Pearl millet growth was unaffected by the K treatment in Experiment I, but this treatment increased sudangrass growth. There was no significant growth response to fertility in Experiment II, however, the Ca + Mg + K treatment tended to have the tallest plants. The fertility treatments did not significantly affect the P content of pearl millet. Pearl millet accumulated much higher amounts of nitrate N than did sudangrass. All plots receiving K singly, or in combination with Ca, and/or Mg were significantly higher in nitrate N. Nitrate N was significantly decreased by addition of Mg and by Ca, but to a lesser degree. Drought conditions seemed to intensify the influence of K on increasing forage nitrate N concentrations. Regulation of Mg and K fertility may help lessen the possibility of nitrate toxicity in pearl millet and sudangrass.
Potassium Azide as a Nitrification Inhibitor1
Authors: Hughes T. D. , Welch L. F.
Published: July 2010

The effect of 0, 2, 4, 8, 16, and 32 ppm KN3 on nitrification in soil was studied at 30 and 10 C. At both temperatures, KN3 was an effective nitrification inhibitor. At 30 C, 75 ppm of added NH4 + disappeared in 2 weeks where no KN3 had been added as compared to 4 weeks at the 32 ppm KN3 rate. At 10 C, 4 weeks were required for the NH4+ to disappear at 0 ppm KN3, whereas more NH4+ was present after 18 weeks than initially where 32 ppm KN3 was applied. Concentrations of (NO2‐ + NO3‐)‐ N were found to be similar at all KN3 rates once the NH4+ had disappeared. This indicates that KN3 had no effect on mineralization‐immobilization relationships. The soil pH for both incubation temperatures was 6.8.

The effect of 4 ppm KN3 in soil incubated at 30 C was studied at soil pH levels of 4.5, 6.0, and 7.5. The NH4‐N and (NO2‐ + NO3‐)‐N concentrations during 4 weeks incubation indicated that KN3 did not inhibit nitrification at soil pH levels of 4.5 and 6.0 but that nitrification was inhibited at pH 7.5. At 30 C, KN3 does not appear to be an effective nitrification inhibitor for soils of pH less than 6.0.
Phosphorus‐Iron and Phosphorus‐Zinc Relationships in Corn (Zea mays L.) Seedlings as Affected by Mineral Nutrition1
Authors: Adriano D. C. , Paulsen G. M. , Murphy L. S.
Published: July 2010

The P‐Zn and P‐Fe relationships in corn (Zea mays L.) seedlings as affected by high P levels and low and high levels of other nutrients, varied individually, were determined. With high P levels, shoot growth was increased only by high Zn, but was decreased by deficiencies of other nutrients. N and K favored P nutrition more than Fe or Zn nutrition. Ca antagonized P, Zn, and Fe, while Mg synergized P and Zn but not Fe. Similarly, Cu and Mn antagonized shoot P and Fe concentrations and had little effect on shoot Zn concentrations. The most marked interaction at high P levels was between Fe and Zn, which mutually antagonized translocation more than absorption.
Soybean Canopy Structure and Some Radiant Energy Relations1
Authors: Luxmoore R. J. , Millington R. J. , Marcellos H.
Published: July 2010

Measurements were made of canopy outline, leaf area index and the radiation environment of a soybean row crop at several stages of growth. The major change with time in canopy geometry occurred in the uppermost hemicylinder of leaves which increased in height and lateral spread. The proportion of energy reflected and reradiated from the top of the canopy increased during the season and this may be related to increases in both leaf area index and lateral spread of the crop.

A nonlinear relationship between the incoming radiation and the energy received at a plane within the crop indicated that changes in leaf inclination during periods of high insolation gave a more open canopy.

Measurements of energy in the 310‐ to 2750‐nm waveband showed that from 65 to 85% of the radiation received at a plane in the crop came from the upper hemisphere and the remainder was reflected to the under surface. Extinction coefficients, calculated for solar radiation, showed large changes with height in the canopy, indicating that the assumptions made in applying the Bouguer‐Lambert law to energy relations in a soybean canopy are not valid. Any model of the radiation relations of row crop canopies must account for energy changes in both the vertical and lateral directions.
Nitrate Accumulation in Vegetables. I. Spinach Grown in Upland Soils1
Authors: Barker A. V. , Peck N. H. , MacDonald G. E.
Published: July 2010

The nitrate concentrations in spinach (Spinacia oleracea L.) blades and petioles were determined for different sources and times of application of N fertilizers to a Honeoye fine sandy loam and a Lima silt loam to determine the effect of N fertilization on the concentration of nitrates in the plant parts used for consumption for food.

Nitrate concentrations were determined potentiometrically, using a nitrate‐selective ion electrode, on plant samples taken at time intervals after N fertilization and at harvest stage for processing.

Nitrogen fertilization substantially increased the NO3 concentrations of spinach grown in upland soils. The following observations were significant: (a) More NO3 accumulated in leaves of plants broadcast with N fertilizers before planting than if an equivalent amount of N fertilizer was supplied by sidedressing one week before harvest. (b) The N carrier was a significant factor in governing NO3 accumulation when it was applied as sidedressing.
Detection of Differences Between Means: A Monte Carlo Study of Five Pairwise Multiple Comparison Procedures1
Authors: Carmer S. G. , Swanson M. R.
Published: July 2010

Computer simulation techniques were used to study the properties of five procedures for pairwise multiple comparisons of treatment means. Procedures studied were: (1) the ordinary least significant difference, LSD, (2) use of a preliminary F test with the least significant difference, FLSD, (3) Tukey's Significant Difference, TSD, (4) Duncan's Multiple Range Test, DMRT, and (5) a relatively new Bayesian modification of the least significant difference, BLSD. Results presented are based on simulation of 60,000 experiments involving 3, 4, 6, or 8 replicates of either 10 or 20 treatments with various patterns of homogeneity among treatment means.

Observed rates of correct decisions when real differences occur among treatments, and observed rates of three types of possible errors indicated that the FLSD, DMRT, and BLSD are more appropriate for use in research than the LSD or TSD. Based on the statistical properties observed in this study a choice among the FLSD, DMRT, and BLSD is difficult; however, the FLSD may be preferred due to its familiarity to researchers and its simplicity of application.
Dryland Evaporative Flux in a Subhumid Climate: IV. Relation to Plant Water Status1
Authors: Ritchie J. T. , Jordan W. R.
Published: July 2010

This investigation was conducted to determine the relations between plant water status and plant evaporation rates for use in defining critical limits of soil water availability to field crops. Seasonal trends in relative water content (RWC) of grain sorghum [Sorghum bicolor (L.) Moench] were measured concurrently with evaporation rates during a prolonged drying cycle in 1969. When the available soil water supply was depleted beyond a critical threshold, called the lower limit for potential evaporation (LLE0), daily evaporation rates began to decline substantially below the level of energy available for evaporation. Before the LLE0 threshold was reached, midday leaf RWC values were approximately 0.90. Afterwards, these values declined in proportion to measured decreases in daily evaporation. Early morning RWC values did not decrease significantly until 8 days after evaporation began to decline. Leaf stomatal response to soil water deficit was evident when daylight leaf diffusion resistances changed from 2 sec/cm before the LLE0 threshold to about 25 sec/cm 10 days after the threshold was reached.

These results indicate that plant water status can be used in conjunction with measured changes in soil water content to define the amount of soil water extractable by plant roots for a particular crop, soil, and climate between the maximum water‐holding capacity of the soil and the LLE0 threshold. These critical soil water parameters can be applied to predicting evaporation in two stages: (i) a freely evaporating stage when evaporation is limited by the amount of energy available for evaporation; and (ii) a falling rate stage when evaporation declines below the potential rate. An equation is proposed for predicting evaporation in the falling stage as an exponentially decreasing function of time after the LLE0 threshold is reached.
Controlling Soil Crusting with Phosphoric Acid to Enhance Seedling Emergence1
Authors: Robbins C. W. , Carter D. L. , Leggett G. E.
Published: July 2010

Obtaining adequate and uniform stands of small seeded crops is often a serious problem on soils susceptible to crusting. A study was conducted to determine if spraying dilute phosphoric acid in narrow bands along the seeded rows would increase sugar beet (Beta vulgaris L.) seedling emergence by preventing or minimizing soil crusting and provide the needed nutritional P for crop production. Dilute phosphoric acid was sprayed along rows seeded to sugar beets on a Portneuf silt loam. Several acid concentrations and P rates were applied. Stand counts were made before and after thinning, and P concentrations were measured in sugar beet petioles sampled at three dates during the growing season. Laboratory studies were conducted to determine the effects of the phosphoric acid on soil properties.

Applying 69 kg P/ha as dilute phosphoric acid in liquid volumes of 650 to 1,300 liters/ha reduced crusting by increasing aggregate stability in the soil surface, increased sugar beet seedling emergence, and provided the P needed by the sugar beet crop. The acid dissolved CaCO3 and MgCO3 in the soil surface freeing Ca++ and Mg++. The cations likely reacted with PO4Ξ from the acid to form slightly soluble Ca and Mg phosphates that acted as cementing agents in soil aggregates. Using dilute phosphoric acid to reduce crusting may be equally effective for assuring satisfactory stands of other crops on calcareous soils.
Reflected Radiation from a Soybean Crop1
Authors: Blad Blaine L. , Baker Donald G.
Published: July 2010

The albedo, defined as the percentage of incoming solar radiation that is reflected, was measured continuously over a soybean crop [Glycine max. (L.) Merr.] during the 1968, 1969, and 1970 growing seasons at St. Paul, Minn. The study was undertaken to establish average albedo values for soybeans and to evaluate the effects of increasing crop cover on the albedo. The average daily albedo ranged from 24% to 27% with complete soybean cover. The albedo of the moist soil was approximately 10.5% with no cover and increased at the rate of about 1.3% for each 10% increase in crop cover. Because this relationship held true over the entire growing season, it should be possible to accurately estimate soybean cover from albedo measurements once the growth characteristics of a variety have been established.

It was also possible during the study to examine the effects of soil moisture and lodging on the soybean albedo. It was found that with full cover the albedo decreased at low soil moisture because the soybean leaves wilted and became more vertically oriented, thereby permitting increased penetration of incoming solar radiation. Before canopy closure, particularly early in the season, low soil surface moisture caused a marked increase in albedo. Severe lodging during mid‐August 1970 caused a marked decrease in albedo.

Failure to properly shield the inverted Eppley pyranometer was shown to cause an increase in the daily average albedo of as much as 7.5% because of internal reflection from the pyranometer dome.

An average albedo of 25.9% was obtained for two dear days. It was noted on these days that morning albedoes were higher than evening albedoes at the same solar altitudes. This was attributed to temporarily wilted, drooping leaves, and to increased leaf flutter from stronger afternoon winds. The average daily albedo for two cloudy days was 24%.
Mineral Content of South Dakota Bread Wheats: Extent and Nature1
Authors: Fine L. O.
Published: July 2010

An investigation of ash levels in South Dakota bread wheats was conducted to determine range of ash content normally encountered over the state and within a few years‘ time, and nature of cation constituents in ash which vary, and possible causes of ash variation. “High ash” wheats have experienced price discrimination at terminal markets for various reasons.

Ash content was determined by electric furnace ignition and major base constituents by atomic absorption and flame emission techniques.

Ash surveys using seed certification samples, extension fertilizer demonstration trials, and county variety trials showed maximal variations of 16% and 37% ascribable to variety and location effects, respectively. Wheat produced in variety ✕ fertilizer ✕ plant density experiments at 3 locations in 1969 and one in 1970, showed major ash differences to be due to variety, with lesser effects to N fertilizer and no consistent effects of plant density. The order of cationic abundance found was K > Mg > Na > Ca, with Na and Ca very minor, aggregating <0.10%. Additions of 67 and 134 kg N/ha significantly depressed total ash at two locations in 1969, but increased ash at one location in 1970. N additions significantly increased Mg content of ashes in both years of the experiment.

In a group of 51 wheat samples from a reclamation experiment on a salt‐affected soil association, no relationship could be observed between wheat content of Mg and K and exchangeable or total extractable soil content of the same.
Radial Diffusion of Free Energy In Stem Phloem: An Experimental Study1
Authors: Molz Fred J. , Klepper Betty , Browning V. Douglas
Published: July 2010

The rehydration of a water‐stressed cotton (Gossypium hirsutum L.) stem was studied experimentally. The main objective of the experiments was to ascertain if a proposed diffusion theory can describe the dynamics of the rehydration process. Stem shrinkage was induced by allowing the soil‐root system of potted cotton plants to dry by evapotranspiration. Tension in the xylem was then released suddenly by severing the stem under distilled, degassed water, with the subsequent increase in stem diameter monitored with an LVDT. From the basic data of stem diameter vs time, fractional uptake curves for free energy were computed and compared with predictions derived from theory. The comparisons indicate that the theory is applicable at least to first order. The overall study illustrates the intimate involvement of the xylem and phloem as far as radial water exchange is concerned.
Forage Potential of Soybean Straw1
Authors: Gupta B. S. , Johnson D. E. , Hinds F. C. , Minor H. C.
Published: July 2010

The nutritive value of soybean [Glycine max (L.) Merrill] straw was studied because of the vast acreage grown in the U.S. and the marked expansion scheduled for this crop in developing countries. Nutritive value was estimated on greenhouse and field‐grown plants and plant parts at various stages of maturity by using standard techniques of forage chemical analysis, in vitro dry matter disappearance (IVDMD), and measuring intake and digestibility by ewes.

Cell wall constituents (CWC) and lignin percentage of stems increased progressively from 643 and 10.5% at flowering to 79.4, and 21.5%, respectively, at maturity. Pods increased only up to 52.2% CWC and 8.6% lignin at maturity. The average figures for CWC, acid detergent fiber (ADF), lignin, and crude protein of the mature samples obtained behind a combine were 77.0, 60.0, 16.5 and 4.9%.

Forage yields on hand.harvested, mature, field‐grown soybeans were 2262, 4419 and 4076 k.g/ha for ‘Wayne,’ ‘Dare,’. and ‘Hill’ cultivars. The average IVDMD was 25.8% for stems and 59.6% for pods from the mature field‐grown soybean straw.

The average consumption of dry matter of a mature straw diet containing minerals and 8.5% soybean meal by 6‐ to 7‐year‐old ewes, was 19.8 g/day/kg live weight when ground and 16.7 when fed unground. Digestibility coefficients of unground and ground straw diets, as determined by the lignin ratio technique, averaged 35.9, 49.7, 27.3, 30.6, 50.6, 17.8 and 44.4, 51.2, 28.0, 42.9, 58.8, 21.7% for dry matter, crude protein, CWC, ADF, cellulose, and hemicellulose.
Tillage and Fertilization of Corn Grown on Lespedeza Sod1
Authors: Adams W. E. , Morris H. D. , Giddens Joel , Dawson R. N. , Langdale G. W.
Published: July 2010

Little research information is available on optimum soil management for row crops grown in the southeastern U.S. on land planted for many years to soil‐conserving legumes. A 5‐year field investigation was conducted to determine the effect of tillage and fertility on the yield of corn (Zea mays L.) grown on Cecil soil previously planted to sericea lespedega (Lespedeza cuneata cum de cours. G. Don) for 10 years.

Without fertilization, conventional planting produced an average of 608 kg/ha more corn than lister planting without soil preparation. At a high level of fertilization (134‐58‐112 kg/ha of N‐P‐K), tillage did not affect yields.

Lister‐planted corn exhibited a stunted and chlorotic condition until 40‐ to 50‐days‐old. Neither lime nor micronutrients alleviated the problem of affected yield. Conventionally planted corn was not chlorotic or stunted.

Sericea lespedeza residue was readily mineralized during a 203‐day incubation period in the laboratory. Mineralization of N was highest in soil mixed with leaves and lowest in soil mixed with stem residues.

Corn yields were increased as much as 1,719, 947, and 734 kg/ha by N., P, and K, respectively, the first year following sod. A similar response was obtained for N for the average 5‐year yield, but no significant increase was obtained from P or K. The results indicate that optimum fertilization of corn grown following sericea does not differ significantly from that for continuous corn.