bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Salt‐Oxygen Levels Influence Plant Growth1
Authors: Aubertin G. M. , Rickman R. W. , Letey J.
Published: July 2010

Two salt‐oxygen‐plant growth experiments, one a solution culture, the other involving soil, were conducted in a greenhouse using tomato plants (Lycopersicon esculentum Rutgers) as the test plant. Plant growth as measured by eight growth indices was shown to be adversely affected by decreasing the oxygen content of the aerating gas from 21% or by increasing the salt level of the growth media from 20 meq/liter. Simultaneous changes in both the oxygen and salt levels generally produced significantly greater changes than could be accounted for by considering the effects brought about by the salt and oxygen levels considered independently.

Tomato plants affected by high salt or low oxygen levels had similar characteristics of stunting and small, somewhat cup‐shaped, wrinkled, dark green leaves. Severity of the symptoms increased as either the salt level increased or the oxygen level decreased. Severe symptoms appeared at combinations of oxygen and salt levels which individually did not cause the symptoms to appear.

Reducing the oxygen level from 21% had a significantly adverse effect on growth at all salt levels, while increasing the salt level from 20 meq/liter caused varying amounts of growth reduction depending on the oxygen level. At any given level of one treatment, increasing the stress of the other treatment generally resulted in a considerable reduction in growth, although where growth was already markedly decreased, applying a more severe treatment produced smaller additional detrimental effects.

In both the solution and soil experiments the salt effect was greatest under conditions of adequate oxygen. Under low or inadequate oxygen levels the salt effect appeared but to a much smaller extent.
Direct Observation of Cotton Root Growth under Field Conditions1
Authors: Pearson Robert W. , Lund Zane F.
Published: July 2010

Under favorable soil chemical and physical conditions, cotton primary roots elongated 3.3 times as fast as stems up to July 13. At that time roots had reached the 170‐cm depth, the maximum depth at which observation could be made. The period of maximum root proliferation coincided with the maximum rate of plant height increase and occurred during the period immediately following initiation of the reproductive cycle. There were no identifiable periods of suspense in root extension until the onset of final cessation of root growth. This occurred following maturation of first boll set.
Changes in Composition of Sudangrass and Forage Sorghum with Maturity1
Authors: Farhoomand M. B. , Wedin W. F.
Published: July 2010

Under three managements, stockpiled (no summer cut), hay (one summer cut), and pasture (three summer cuts), significant differences were noted in percent dry matter, crude protein, and crude fiber in the leaves, stems, and heads of ‘Piper’ sudangrass (Sorghum sudanense (Piper) Stapf) and ‘RP30F’ forage sorghum (Sorghum bicolor (L.) Moench) with advancing maturity. These changes were particularly striking when the forage was saved for fall use. Generally, sudangrass analyzed significantly higher in percent dry matter and crude fiber but lower in percent crude protein than forage sorghum. Percent dry matter in the leaves, stems, and heads of both species differed significantly with management and increased with maturity, except in the heads of sudangrass under the stockpiled management where percent dry matter increased until full maturation and decreased abruptly thereafter, possibly because of seed shattering and loss. In both sudangrass and forage sorghum, the heads were highest in percent dry matter, the leaves intermediate, and the stems lowest. Percent crude protein and crude fiber differed significantly between species, plant parts within each species, and dates of sampling. Percent crude protein generally decreased as the date of sampling was delayed. The leaves of both species were highest in percent crude protein, the heads intermediate, and the stems lowest. Percent crude fiber increased in the leaves and stems of sudangrass, but decreased in the leaves and stems of forage sorghum as plants matured. Percent crude fiber decreased in the heads of both species with advancing maturity.
Boron and Manganese Effects on Cotton Yield, Lint Quality, and Earliness of Harvest1
Authors: Anderson O. E. , Boswell Fred C.
Published: July 2010

Manganese (2.23 and 4.46 kg/ha) and boron (0.45 and 0.89 kg/ha) were applied as a sidedressing to cotton on 13 different soils in Georgia. Both total yield and the percent of that yield obtained at first harvest were increased without detrimental effect on lint strength, length, or fineness, despite the fact that no deficiency symptoms of Mn or B were observed on the check plots. Yield increases were negatively correlated with the water soluble soil Mn and B, and positively correlated with pH. With few exceptions, the Mn and B content of soil and leaf samples from untreated plots were higher than those usually rated as deficient, suggesting that cotton yield and earliness of harvest benefit from relatively high levels of these elements.
Competition Between Ladino Clover Seedlings and Established Orchardgrass in Nutrient Solution Cultures1
Authors: Gross C. F. , Robinson R. R.
Published: July 2010

Ladino clover seedlings were grown alone and in association with established orchardgrass in nutrient solution cultures in the greenhouse. Techniques were devised to control competition for light. Nutrient solutions at each of two concentrations were (1) changed frequently and (2) not changed during the experiment. Where solutions were not changed, pH values were controlled and nutrients replenished.

There was no evidence that actively growing roots of well‐established orchardgrass released substances in the nutrient solution that affected the yield of ladino clover seedlings.
Effects of Nitrogen Fertilizer on an Old Stand of Crested Wheatgrass1
Authors: McGinnies William J.
Published: July 2010

Nitrogen fertilizer, in the form of urea, was applied to a 16‐year‐old stand of crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.] at rates of 0, 22, 45, 67, 90, and 112 kg N/ha/yr. Annual and biennial applications were made over a 6‐year period starting in 1962. Average herbage yield was increased by the addition of N at all rates. The greatest increase in herbage yield per kg N applied was at the 22‐kg/ha rate; the increase in yield per kg N applied declined as the rate of N increased. Total average herbage yield was highest at the 67‐, 90‐, ll2‐kg rates. Annual fertilizer applications produced significantly higher average yields than biennial applications. The unfertilized plots declined in productivity during the period covered by the study, but as little as 22 kg N/ha/yr appeared to prevent the stand deterioration.

A one‐time‐only application of 0, 22, 45, 67, 90, 112, 135, 180, 225, and 449 kg N/ha was applied in 1962. The 22‐ and 45‐kg/ha rates increased herbage yield in the first year, and 67‐ to 225‐kg/ha rates increased yields through 1965. The 449 kg/ha rate increased yield through 1966, but had no significant effect in 1967.

The magnitude of the response to N and the relative efficiency per kilogram applied depended upon moisture availability.
Response of Plants to Polyphosphate on Calcareous Soils1
Authors: Stroehlein J. L. , Sabet S. A. , Clementz D. M.
Published: July 2010

Ammonium polyphosphate (APP) was compared to ammonium orthophosphate (AOP) with successive crops grown on four calcareous soils in the greenhouse. Barley (Hordeum vulgare) the first crop, responded to P on three of the soils, with AOP superior to APP on two soils. With tomatoes (Lycopersicon esculentum), the second crop, APP was significantly better than AOP on all soils. APP was a satisfactory P source and was superior to AOP for the second crop.
UV Aflatoxin Quantitation with Polaroid Recordings1
Authors: Chang Chung‐Min , Lynd J. Q.
Published: July 2010

A method is presented for precise, permanent color recordings of TLC plates used in aflatoxin quantitation. Improvement over black and white film recordings include close duplication of blue and yellow green chroma actually observed with UV fluorescence with less distortion from the differential intensities apparent between the B and G groups with aflatoxin concentration changes.
Growth of Crops in Soils after Herbicidal Treatments for Brush Control in the Tropics1
Authors: Bovey R. W. , Miller F. R. , Diaz‐Colon J.
Published: July 2010

Herbicides 4‐amino‐3,5,6‐trichloropicolinic acid (picloram), a 1:1 mixture of the butyl esters of 2,4‐dichlorophenoxyacetic acid and 2,4,5‐trichlorophenoxyacetic acid (2,4‐D:2,4,5‐T), and a 2:2:1 mixture of the isooctyl esters of 2,4‐D:2,4,5.T:picloram at 6.7, 26.9, and 16.8 kg/ha (6, 24, and 15 1b/A) respectively, were applied as foliar sprays to control guava (Psidium guajava L.). Six crop species were planted in soil collected from each plot, 1, 2, 3, 6½, 9½, and 13½ months after treatment, to detect herbicide residues and to determine crop tolerance. Corn, sorghum, wheat, rice and cotton could be grown without reduction in fresh weight as early as 3 months after application. Soybeans were the most susceptible crop to herbicide residues.
Effect of Time of Molybdenum Application on Soybean Yield and on Nitrogen, Oil, and Molybdenum Contents
Authors: Boswell Fred C. , Anderson O. E.
Published: July 2010

An evaluation of the effects of molybdenum (Mo) on soybeans (Glycine max) when applied at various periods indicated significant yield responses especially on the moderately acid shaly soils. Mo applied as a seed treatment, as a spray at the early stage (20‐cm height), and as a spray at the pre‐bloom stage were not significantly different. However, these treatments resulted in significantly greater yields than spray treatments applied 6 or 9 weeks after the early spray stage. Mo application increased the N and Mo content of the leaves and protein content of the soybeans. A highly significant negative correlation occurred between protein and oil content of the soybeans when various Mo treatments were applied.
pH Effect on Root Growth and Water Uptake by Plants
Authors: Thorup James T.
Published: July 2010

A direct pH effect upon root growth and water uptake by plants was demonstrated. When the OH‐ ion concentration increased sufficiently, the curtailment of water uptake was almost instantaneous.

Extreme wilting of plants growing in nutrient solution occurred in a matter of 15 min after the addition of Na2CO3 when temperatures were sufficiently high to cause rapid transpiration. Roots were damaged in a similar period of time as indicated by an over all discoloring of the root system and a blackening of root tips and small laterals. Plants treated with an equivalent amount of NaCl showed no adverse effects.

Since the addition of Na2CO3 to nutrient solutions produced excessively high pH values, a study of the effect of pH upon plant growth was made. Growth was curtailed at pH 9 and above. Wilt and root damage occurred at these pH values similar to that observed with Na2CO3 treatments. The critical pH for tomato plants (lycopersicon esculentum) was 8.8 if the plants were established in nutrient solution for several days before treatments were added. For young developing roots, the critical pH was even lower, about 8.2. The only effect of different anions upon plant growth under these conditions proved to be a buffering effect upon the solution pH. Adventitious roots failed to grow in solutions buffered at 8.2 or above. New growth occurred readily at pH values below 8.0 with a concomitant revitalized plant growth.
Relationship Between Corn (Zea mays L.) Yield and Leaf Levels of Ten Elements1
Authors: Peck T. R. , Walker W. M. , Boone L. V.
Published: July 2010

Corn (Zea mays L.) yields were obtained at four locations from experimental plots receiving varying rates and combinations of N, P, and K. A quadratic polynomial was used to measure the relationship between leaf levels of N, P, and K, and corn yield. This function had an R2 of 0.45. A second quadratic polynomial using leaf (sixth leaf) levels of 10 nutrients, N, P, K, Ca, Mg, B, Cu, Fe, Mn, and Zn was fitted to yield, and resulted in an equation with an R2 of 0.81. From a potential of 65 linear and second order terms, 37 were fitted using a stepwise regression analysis procedure. The additional variation explained by the second regression model was statistically significant.

Regression analysis of corn yields with leaf levels of 10 elements as independent variables revealed several significant main effects and interactions. The significant effect of numerous interactions indicates that the critical level of any particular nutrient varies with leaf levels of other nutrients. The significant effect of leaf levels of micronutrients upon corn yields indicates some merit in micronutrient research even though visual deficiency symptoms are not apparent.
Germination Response of Rice Seeds to Constant and Alternating Temperatures
Authors: Chaudhary T. N. , Ghildyal B. P.
Published: July 2010

Germination response of rice seeds to constant temperatures of 4.5, 10, 15.5, 21, 26.5, 32, 37.5, and 43C and alternating temperatures of 41/24, 24/7, and 41C/7C with temperature periods of 8, 12, and 16 hours under high/low and low/high sequence was studied. No germination was observed at 43 or 4.5C. The maximum and the minimum temperatures for germination were found to be 41 and 7C. The temperature region of 26.5 to 37.5C appeared to be favourable for germination of rice seeds. Alternating temperatures as such showed no advantage over the constant temperatures. In case of inhibitive high or low temperatures, the alternation of temperatures promoted germination. Exposure of seeds to low temperature for 8 to 12 hours was more favourable than exposure for 16 hours. The sequence of temperatures did not show any definite effect.
Magnesium‐Phosphorus Interrelationships in Tomatoes
Authors: Hipp Billy W. , Gerard C. J.
Published: July 2010

Tomato (Lycopersicon esculentum) plants were grown in nutrient solution with Mg levels which varied from 0.96 ppm to 96 ppm and with P levels of 5 and 31 ppm. At low levels of Mg better growth was obtained when the P level was low. At high levels of Mg better growth was obtained when the P level was high. A nutrient solution containing 96 ppm of Mg promoted plant growth when the P concentration was 31 ppm but reduced growth when the P concentration was 5 ppm. Phosphorus fertilization of tomatoes grown on clay soils reduced the Mg content of the leaves from 1.2 to 0.65%. Analysis of leaves of commercial tomato fields during the late bloom stage showed a negative relationship between Mg and P (r = —0.896).
Photosynthesis under Field Conditions. XB. Origins of Short‐Time CO2 Fluctuations in a Cornfield1
Authors: Lemon E. R. , Wright J. L. , Drake George M.
Published: July 2010

Studies of the vertical distributions of CO2 fluctuation in a cornfield were made in the 4‐to 0.25‐cycle/min frequency range. Amplitude of fluctuations decreased with height above the ground. Frequency in this range appeared rather constant, however. Sources and sinks for CO2 within the cornfield contribute to the fluctuations; however, eddy structure originating inside and/or outside the cornfield plays an important role too.
Relationship Between Soybean Yields and Leaf Levels of 10 Elements Determined with Different Regression Models1
Authors: Walker W. M. , Peck T. R. , Carmer S. G.
Published: July 2010

Soybean leaf samples and yields were obtained from experimental plots receiving varying levels of P and K. Yields were regressed on a quadratic polynomial with leaf levels of P and K as variables. This regression had an R2 of 0.495. Yields were regressed on a second quadratic polynomial with leaf levels of N, P, K, Ca, Mg, B, Cu, Fe, Mn, and Zn as variables. With the stepwise regression procedure used for fitting the model, 22 linear and second order terms were fitted to the data. This regression had an R2 of 0.813. The additional variation accounted for by the second regression was statistically significant.

Other polynomial regressions were fitted to the data using ratios of elements as independent variables, but none were superior to the quadratic polynomial in terms of R2 values.
Soil Water Supply and Depletion Pattern Differentiate among Zea, mays L. Single‐ and Double‐Cross Hybrids1
Authors: Bruce R. R. , Sanford J. O. , Grogan C. O. , Myhre D. L.
Published: July 2010

The relationship of irrigation response of several double‐ and singe‐cross Zea mays L. hybrids to inbred line composition and effectiveness in supplying the plant water requirements from the soil water supply was investigated. An experiment involving 25 double‐cross hybrids showed that 16 of these hybrids gave a 10% or greater grain yield response to irrigation, whereas the remainder showed very little or no yield increase. Certain hybrids produced about as well without irrigation as the highest yielding irrigation‐responsive hybrids. Subsequent experiments examined the irrigation response of several single‐cross hybrids and their double‐cross products. In a season of severe drouth requiring major irrigation, yield response of the double‐cross products to irrigation was predicted very well by averaging the yield response of the four non‐parental single crosses of the four inbreds involved.

Examination of the soil water depletion pattern of single‐cross hybrids has shown that the yields are related to the capability of the plant to meet its water requirements during the critical fruiting period from existing soil water supply. Cited as examples are the cytoplasmic male‐sterile versions of several single crosses which rather consistently yield better than their fertile counterparts.
Translocation of Labelled Sucrose from Selected Cotton Leaves1
Authors: Sabbe Wayne E. , Cathey George W.
Published: July 2010

Studies were made to determine the movement of metabolic‐14C from sucrose during flowering and fruiting of the cotton (Gossypium hirsutum) plant. The translocation and sinks were studied by using radioactive 14Csucrose applied at various locations on the plant and at various stages of plant development.

Label from 14C‐sucrose was found to translocate from fruiting branches to roots of cotton plants before young bolls were initiated. However, upon initiation of bolls the roots did not continue as a major sink. At the time of first flower the label showed a tendency to translocate to regions of rapid growth (i.e., young bolls) both above and below the treated branch. There was a tendency for the fruiting branch more nearly in vertical alignment with the treated branch to receive a larger quantity of translocate than branches on the opposite side of the stem.

When the osmotic pressure of the liquid nutrient culture was increased, the 24C‐label showed a tendency toward downward translocation during the flowering stage of the plant development. The radioactivity of the roots increased when the osmotic pressure of the nutrient solution was increased.
Effects of Sample Drying Procedure on Chemical Composition and In Vitro Digestibility of Coastal Bermudagras1
Authors: Wilkinson S. R. , Dawson R. N. , Adams W. E.
Published: July 2010

‘Coastal’ bermudagrass (Cynodon dactylon L.) grown under three levels of N‐K fertilization and three growth intervals was air‐dried at 23C and over‐dried at 57C, 75C, and 100C to determine sample‐drying effects on cell wall constituents (CWC), acid‐detergent fiber (ADF), acid‐detergent lignin (ADL), and in vitro digestibility. Heat‐dried samples were compared with quick‐frozen, freeze‐dried samples from the same plots. Levels of N‐K fertilization were 224‐112, 672‐336, and 1,120‐560 kg N‐K/ ha per year, and growth intervals were of 2‐, 4‐, and 6‐ week durations under irrigated conditions.

Oven‐drying increased CWC, ADF, and ADL contents of forage over those of freeze‐dried forage. Cell wall constituents were increased most at drying temperatures of 75C or above, with CWC content of immature samples being increased relatively more than that of mature samples. Acid‐detergent fiber content and ADL content were significantly increased by longer growth intervals, with one exception—ADL content of 2‐week‐old samples dried at 100C was similar to that of 6‐week‐old forage. In vitro digestibility expressed as percent dry matter disappearance was greatest in freeze‐dried samples and least in air‐dried samples. Growth interval and sample‐drying interacted in that 2‐week‐old, OD‐100C forage had similar digestibility to 4‐week‐old quick‐frozen, freeze‐dried forage. Differences in in vitro digestibility between the QF‐FD, OD‐75C, or OD‐57C were small and nonsignificant.

Forage samples oven‐dried to constant weight at temperatures of 75C or less in 48 hours gave results representative of the agronomic treatment effects comparable to those of the quick‐frozen, freeze‐dried samples. Cells wall constituent fractions appeared most affected by oven‐drying; however, even though changes in response to growth interval and N‐K level were reduced by oven‐drying, interpretation of treatment differences were consistent.
Corn Earworm Injury to Maize as Affected by Plant Density1
Authors: Widstrom Neil W.
Published: July 2010

When plant densities were varied for five sweet corn, Zea mays (L.), hybrids, a within‐row spacing of 30.5 cm sustained significantly less corn earworm (CEW), Heliothis zea (Boddie), injury than spacings of 61.0 and 90.5 cm during 2 of 3 years. Differences among spacing means for CEW injury could not be removed through adjustment by covariance techniques involving tiller number, days to mid‐silk, or husk extension as covariates. The present practice of avoiding non‐competitive plots when recording CEW injury must be continued if valid comparisons among hybrids are to be made.
Use of a Concurrent Mitscherlich Model in Fertilizer Evaluation1
Authors: Engelstad O. P. , Khasawneh F. E.
Published: July 2010

A concurrent Mitscherlich model that can be fitted to a family of response curves via a multiple regression program is shown to be suitable for evaluation of fertilizers. This model provides for a common limiting yield and a common intercept, can be fitted by standard regression programs, and the coefficients obtained are compared readily by statistical tests.
Programmed Instruction in Soil Science: An Evaluation1
Authors: Shafer J. W. , Crabtree R. J. , Foth H. D.
Published: July 2010

The introductory course in soil science has been taught at Michigan State University since the fall of 1966 as a multimedia course. The lecture‐laboratory format was changed to include one lecture, one recitation and about three hours of nonscheduled programmed laboratory per week. The programmed part of the course consists of preparatory reading assignments, a taped‐slide presentation of new material and laboratory investigations, displays that are integrated with the tape presentation, and homework problems and questions. About two‐thirds of the students found this to be one of the most stimulating courses they have had in college. The integration of laboratory work with the lecture was preferred 2 to 1 over the traditional separation of laboratory and lecture. Staff found this approach more conducive to individualized help of students. Administrators find it easier to schedule courses, fewer pieces of scientific equipment are required, and there is more efficient use of space. Its major disadvantage is the extensive time required to develop the program and its initial cost.
Manganese Toxicity of Soybeans as Related to Soil and Fertility Treatments1
Authors: Parker M. B. , Harris H. B. , Morris H. D. , Perkins H. F.
Published: July 2010

An abnormal leaf characteristic of soybeans [Glycine max (L.) Merrill], described as crinkle leaf, was associated with high levels of water‐soluble soil and leaf manganese (Mn). Symptoms appeared on soybeans in a pot experiment using Hiwassee loam soil but were not evident on plants growing in Tifton loamy sand. An application of MnSO4, induced symptoms in soybeans on Tifton soil, and lime alleviated symptoms on Hiwassee soil. Symptoms included severe crinkling, interveinal chlorosis, necrotic spotting of leaves, and malformation of pods which resulted in more single seeded pods. Heavy rates of commercial fertilizer on a State loam soil in a field experiment caused similar leaf symptoms on soybeans. Symptoms in the field were associated with increased soil acidity, increased water‐soluble soil Mn, and high leaf Mn. Chicken manure applied at rates equivalent to commercial fertilizer N‐P‐K content slightly decreased soil acidity and produced normal plants. In the field, symptoms occurred at the pod‐fill stage during a period of high soil moisture. Yields were not affected by the toxic condition.
Water Pollution Potential Estimated from Farm Nutrient Budgets1
Authors: Frink C. R.
Published: July 2010

Estimates of the yield of nutrients to waterways from wooded and cultivated land vary considerably. Some of this variability can be attributed to the large variability in the N and P content of runoff water, to analytic uncertainties, and to the difficulties of obtaining accurate flow measurements. As an alternative assessment of agricultural eutrophication, nutrient budgets were derived for the highly specialized dairy farms in the Northeast. This analysis showed that under certain conditions these dairy farms could contribute significant amounts of nutrients, particularly nitrate, to ground water. However, this loss of nutrients can be minimized by providing adequate cropland per cow, by selecting crops and animals that are efficient users of N, and by applying both manure and commercial fertilizers during the growing season.
Pangolagrass Performance under Different Levels of Nitrogen Fertilization in Hawaii1
Authors: Whitney A. S. , Green R. E.
Published: July 2010

Pangolagrass was grown on a Humic Latosol at 650 m elevation in an area of 170 cm average annual rainfall with relatively dry summers. Five levels of nitrogen from 0‐640 kg ha−1 yr−1 were applied as (NH4)2SO4 over a year period. Average annual dry matter (DM) yields ranged from 3,780 kg (control) to 18,000 kg/ha, and response to succeeding increments of N ranged from 30 units of DM per unit of N for the first increment (160 kg) down to 10 units for the 480‐640 kg increment. Yields were depressed when average night temperatures were ≤ 15C and during dry periods, but yields were significantly increased by fertilization even during these periods. Percentage crude protein fluctuated with season, being highest during the cooler months. Crude protein levels were influenced only slightly by low rates of fertilization but were raised by the higher N rates to levels sufficient to insure efficient utilization by livestock. The average production of forage under clipping indicated feeding capacities ranging from 1.1 animals (360 kg steers or heifers) per ha for the control to 7.5 animals per ha for the highest N level.

Recovery of applied N increased from 36% for the first increment to 64% for the third increment, with a somewhat lower recovery for the final increment. Soil pH was reduced by 0.10‐0.15 units for each ton of (NH4)2SO4 applied. Liming the soil raised pH from 5.6 to 6.3 but did not influence yields of DM or crude protein. Critical levels for potash sufficiency were established at 0.11 meq/100 g of soil or 1.0% of the dry forage.
Pneumatic Sample Slicer1
Authors: Heinemann William H. , Carter J. N.
Published: July 2010

The design and operation of a pneumatically powered sample slicing machine for potatoes, sugar beets, and similar crops are described.
Effect of Gamma Ray Irradiation on Stability of FeEDDHA Solution at Two pH Levels1
Authors: Romney E. M. , Wallace A. , Wieland P. A. T. , Leo M. W. M. , Wallace G. A.
Published: July 2010

Irradiation of FeEDDHA solutions with gamma rays from a Co60 source resulted in the same type of degredation of the iron chelate that sunlight causes. Effects of both types of radiation were more pronounced at low pH than at high pH. Hydrogen peroxide seemed to have a similar effect.
Effect of the Preceding Crop and Agronomic Practice on Sorghum (Sorghum bicolor L. Moench) and Groundnuts (Arachis hypogaea L.) in the Central Sudan1
Authors: Gerakis P. A. , Tsangarakis C. Z.
Published: July 2010

The influence of sorghum (Sorghum bicolor L. Moench), sesame (Sesamum indicum L.) and groundnuts (Arachis hypogaea L.) unfertilized and fertilized with N and P and of bare and weed fallow on the subsequent season's performance of sorghum and groundnuts was studied in 2‐year trials. The fertilizer rates of 50 kg/ha of N and 22 kg/ha of P applied to the first season's crops affected the yield of the second season's sorghum but not of groundnuts. Two consecutive years of sorghum or groundnuts was deleterious to the second season's yield. Symbiotic fixation in groundnuts was apparently low due to soil acidity and the absence of recent groundnut cultivation. Bare fallow increased moisture by 7.4 mm in the top 1.0 m of soil as compared to weed fallow, but the increase was not reflected in the yield of either crop.
Measuring Thickness of Excised Mature Corn Pericarp1
Authors: Wolf M. J. , Cull Irene M. , Helm J. L. , Zuber M. S.
Published: July 2010

Pericarp thickness of 19 corn (Zea mays L.) samples was determined by two methods: by microscope and by micrometer. Either kernels were frozen and 40 µ sections cut, stained, and measured with an ocular micrometer or kernels were presoaked and pericarp strips were excised for measurement. The excised strips were measured with a plunger micrometer. The coefficient of rank correlation was +0.85**, indicating good agreement between the two methods. The microscopic method produced greater thickness values than the micrometer method. The lower values were probably due to a certain amount of compression by the micrometer plunger. Germinal‐abgerminal ratios differed while right and left sides of the kernels were similar. The excision method is the more economical of the two and does not need specially trained laboratory technicians.
Effect of Moisture Stress at Different Stages of Growth I. Comparison of a Single‐Eared and a Two‐Eared Corn Hybrid1
Authors: Barnes D. L. , Woolley D. G.
Published: July 2010

Single‐eared (Hy × C103) and two‐eared (R71 × B60) corn (Zea mays L) hybrids were grown with their roots confined in 8− ✕ −24‐inch plastic‐lined, soil‐filled trenches. They were subjected to equally severe moisture stress at tassel emergence, silking‐pollination and blister kernel stages. The two‐eared variety was more tolerant to moisture stress at the pollination and blister kernel stages than the single‐eared variety. There was no significant difference in the total grain yield of the varieties to the moisture stress at tassel emergence. Silking was delayed in both varieties during moisture stress at pollination; however, this delay in silking did not reduce the fertilization of the ears and the grain yields of the two‐eared variety as much as the single‐eared variety.

The two‐eared variety extracted significantly more water (1–2%) from the soil when under moisture stress.

A method for measuring the relative turgidity (RT) of the leaves of the corn plants was developed, and the RT of each leaf on the corn plant was different. The RT decreases from apex to base, with each succeeding leaf. Moisture‐stressed corn plants had RT values 18 percent lower in the leaves near the ear shoot than in the leaves near the tassel. This difference in RT could account for the lack of silk emergence while the tassels continued to shed pollen.
Annual Bluegrass Control in Overseeded Bermudagrass Putting Green Turf1
Authors: Bingham S. W. , Schmidt R. E. , Curry C. K.
Published: July 2010

DCPA, bensulide, and diphenamid gave preemergence control of annual bluegrass in freshly tilled soil. Overseeding bermudagrass golf greens with cool season grasses reduced through competition the amount of annual bluegrass cover and provided a desirable putting surface. Annual ryegrass was more effective in this respect than red fescue. Bensulide and DCPA gave control of annual bluegrass and the rates required were partially offset by competing cool season grasses. The cool season grasses seeded one month after treatment were not affected by 5.6 kg/ha of bensulide whereas higher rates gave significant reductions in ground cover with cool season grasses. The margin of safety was not as great with diphenamid. Although bermudagrass growth was retarded in spring with the overseeded cool season grasses, the turf quality was maintained better with the transition from the overseeded grasses to bermudagrass than from the infested annual bluegrass to bermudagrass. Plant competition reduced the number of tillers and weight of annual bluegrass plants in the field and greenhouse studies.
Evaluation of Dewatering and Wilting as Moisture Reduction Methods for Hay‐Crop Silage1
Authors: Derbyshire J. C. , Gordon C. H. , Holdren R. D. , Memear J. R.
Published: July 2010

The wilting and dewatering methods of reducing alfalfa (Medicago sativa L.) moisture prior to ensiling were compared with the direct‐cut harvesting procedure. Field dry matter losses from wilting were essentially zero and were high for the dewatering method. Because of large storage losses of direct‐cut silage, total dry matter losses from the field to the cow were similar for the two nonwilted methods but five times greater than for wilting. Silage temperatures were similar for the three harvesting systems, but silage dry matter bulk density was greatest for the wilted method. Both methods of reducing forage moisture reduced the percentage of the more soluble plant fractions. These differences were not as marked after fermentation. Milking cow response was similar on the three silages in spite of small differences in energy consumption. Wilting appeared superior particularly when animal product per unit of crop land is dominant.
Yield of Corn on Frederick Silt Loam as Affected by Slope and Fertility Treatments1
Authors: Lutz J. A. , Hawkins G. W. , Hoepner P. H. , Martens D. C. , Porter H. C.
Published: July 2010

Experiments were conducted on a B slope (2.5‐7.5%) and on a C slope (7.5‐15%) in 1963, 1964, and 1965, to measure the response of corn {Zea mays L.) on Frederick silt loam to five levels of N applied with three rates of K. Both grain and silage yields were measured. Combined data for the 3 years showed a grain and silage response to only 67 kg N/ha on the B slope, but 134 kg N/ha was required to attain maximum yields on the C slope. Silage yields were increased by 70 and 140 kg K/ha on the B and C slopes, respectively. Grain yields did not respond to applied K on the B slope, but there was a response to 70 kg K/ha on the C slope. Both grain and silage yields on both slopes were similar the 1st year but higher on the B slope in the other 2 years.
Influence of Caging and Pesticide Drenches on Yield and Persistence of Red Clover, Trifolium pratense L.1
Authors: Zeiders K.E. , Newton R. C. , Graham J. H.
Published: July 2010

Drenching of field plots with insecticides resulted in a highly significant increase in yield in each of three harvest years. Fungicide drench had little or no effect on yield and was discontinued after the first harvest year. A significant increase in yield due to caging was observed in 1966 and 1967. Effects of both insecticides and caging on stand survival were highly significant in 1967, but nonsignificant in preceding years. Caging decreased the incidence of virus disease and foliar insect damage, and the percentage dry matter of forage in both check and insecticide‐treated plots. External root rot was severe on all surviving plants after 39 months regardless of treatment. Insecticides favored root growth as evidenced by larger crown diameters.
Results of Changing Light and Temperature Regimes in a Corn Field and Temperature Effects on the Apparent Photosynthesis of Individual Leaves1
Authors: Winter S. R. , Pendleton J. W.
Published: July 2010

Irrigated, heavily fertilized corn (Zea mays L.) was grown in varying light and temperature regimes at Urbana, Ill., in 1967. The corn plants were subjected, during certain developmental stages, to a light and temperature “rich” field environment created with large aluminum reflectors. In addition, the effects of temperature on apparent photosynthesis were studied.

Light and temperature (“radiation”) enrichment greatly increased grain yields. Per plant grain yields for a normal planting, a border row planting, and three “radiation rich” border row plantings (radiation rich from 1.5 m tall to pollination, pollination to maturity, and 1.5 m tall to maturity) were 42.4, 173.7, 206.8, 249.5 and 265.8 g/plant, respectively. Plants in a radiation rich regime, which were cooled by a water mist whenever the air temperature exceeded 29.4 C, yielded 22.2 g/plant (243.6 vs. 265.8 g/plant) less than radiation rich uncooled plants. Therefore, part of the yield increase in the radiation rich regime is apparently due to the increase in temperature caused by the additional radiation.

Investigations of the effect of temperature on the apparent photosynthesis of attached ear leaves in bright sunlight near solar noon indicated optimum leaf and air temperatures of 40.5 and 32 C, respectively. The optimum temperature under ordinary field conditions might well be lower due to any one of several environmental limitations such as inadequate light, water stress, or perhaps inadequate carbon dioxide.
Influence of Nitrogen and Potassium Fertilizers and Dates of Seeding on Yield and Quality of Malting Barley1
Authors: Zubriski J. C. , Vasey E. H. , Norum E. B.
Published: July 2010

Thirteen field trials were conducted to test the effects of rates of N and K fertilizers and seeding dates differing by 2 weeks upon yield, percentage plump kernels, and protein content of malting barley. N fertilizer increased average grain yields on early‐seeded plots by 253, 410, and 534 kg/ha for 22.4, 44.8, and 67.2 kg N/ha, respectively. On late‐seeded plots, same rates of N increased average yields by 264, 303, and 389 kg/ha, respectively. Late seeding reduced average grain yields by 295 kg/ha. Rates of 14 and 28 kg K/ha increased average grain yields by 42 and 48 kg/ha, respectively, on early‐seeded plots and by 71 and 81 kg/ha, respectively on late‐seeded plots. N did not affect average percentage of plump kernels but 14 and 28 kg K/ha increased percentage plump barley by 1.3 and 1.7 percentage units on early‐seeded plots and by 1.8 and 2.7 percentage units on late‐seeded plots, respectively. Late seeding reduced the percentage of plump kernels by 9.8 percntage units. The average protein content of grain was 12.8, 13.1, 13.2, and 13.5% on early‐seeded plots and was 13.4, 13.6, 13.9, and 14.2%percent on late‐seeded plots for O, 22.4, 44.8, and 67.2 kg N/ha, respectively. Late seeding increased the average protein content by 0.7 percentage units. K reduced the average protein content by 0.1 percentage unit on both early and late‐seeded plots.
SeLection of an Alfalfa Plant Part for Phosphorus Analysis1
Authors: Chambliss C. G. , Miller D. A. , Jackobs J. A.
Published: July 2010

The objective of this study was to find an alfalfa (Medicago sativa L.) plant part that (1) has low variability in phosphorus concentration, at a given level of available phosphorus, from one sampling to the next throughout the growing season, and (2) also adequately reflects differences between phosphorus treatments. Alfalfa plant samples were collected from field plots which had been topdressed with different levels of phosphorus. The samples were collected on nine different dates at various stages of maturity in 1966 and 1967. After collection the samples were separated into five plant parts consisting of top leaves, mid‐leaves, top stems, mid‐stems, and bottom stems. The mid stems consistently showed greater sensitivity to phosphorus treatments and had less variation across sampling dates than the other plant parts. Therefore the mid‐stem was considered to be the most suitable plant part to use in determining the phosphorus status of alfalfa.
Calcium and Strontium Relationship in Various Commercially Important Plants1
Authors: Creger C. R. , Holt E. C. , Lovelace D. A.
Published: July 2010

The rate of uptake and the degree of translocation of strontium was investigated, as well as the amounts taken up and the effects on the growth of sorghum, cotton, and bean plants when high levels of strontium are incorporated into the culture medium. Strontium was shown to be taken up readily by the plants and also to be very mobile in actively growing plant tissue. Species differed in growth response to Sr with the greatest retarding (toxicity) effect occurring with bean plants. Species showing the largest percent of Ca in plant tissue in a Sr‐free culture showed the largest concentration of Sr in a Ca‐free culture. Generally, the Sr content of plant tops was higher than roots at all Ca/Sr ratios in the culture solution.
Nitrogen Nutrition and Growth Relations of Tall and Intermediate Wheatgrasses1
Authors: Hylton L. O. , Cornelius D. R. , Ulrich A.
Published: July 2010

Alkar tall wheatgrass, Agropyron elongatum (Host.) Beauv., and Greenar intermediate wheatgrass, A. intermedium (Host.) Beauv., grown separately in nutrient solutions to which NO3‐ had been added at 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16, or 32 meq of NO3‐ per liter. Other nutrients were present in ample amounts. The two grasses were grown concurrently in full greenhouse sunlight for 36 days. Total dry matter production (tops + roots) was significantly reduced with less than 4.0 meq of NO3‐ per liter. Average maximum top weight (oven‐dry) was 2.02 g per plant for tall wheatgrass and 2.76 for intermediate wheatgrass. These top weights were obtained with 8, 16, or 32 meq of NO3‐ per liter. In a common and favorable environment, growth of intermediate wheatgrass was more rapid than that of tall wheatgrass.

Accumulation and distribution of nitrate‐N varied slightly within the plants. At high NO3‐ treatments, matured blades of tall wheatgrass had the highest nitrate‐N concentration (14,600 ppm) whereas stems of intermediate wheatgrass had the highest (16,000 ppm) concentration. Immature blades had the lowest nitrate‐N concentration, about 8,200 and 9,200 ppm, respectively, for tall and intermediate wheatgrasses. Recently matured blades of intermediate wheatgrass had higher percentages of total‐N, nonsoluble‐N (protein‐N), and crude protein than did those of tall wheatgrass. Soluble‐N and nitrate‐N concentrations were generally higher in tall wheatgrass than in intermediate wheatgrass.

The critical nitrate‐N concentrations for growth of these two wheatgrasses is about 500 ppm nitrate‐N in recently matured blade tissue, dry basis.
Prediction of the Nitrogen Requirements of Field Crops Part I. Theoretical Models of Nitrogen Release1
Authors: Reuss J. O. , Geist J. M.
Published: July 2010

Theoretical models for the prediction of the total supply of mineral nitrogen available for crop production have been developed. These models are based on the assumption that the supply of available N is determined by fertilizer N, native soil mineral N, and N released from organic matter. Model No. [1] is of the form Y = b0 + blXl + b11X12 + b2X2 + b22X22 + b12X1X2, where: Y = yield or other parameter dependent on N supply, Xl = fertilizer N plus available soil mineral N, X2 = any index of organic N release, and bl, b2, b . . . are coefficients determined by regression techniques. Model No. [2] is of the form Y = B0 + B1(X1 + aX2) + B2(X1 + aX2)2, where: a represents a release coefficient appropriate to a given X2; B0, B1, B2 are regression coefficients; and Y, X1, and X2 are the same as in Model [1]. The release coefficient a can be evaluated by ratios of coefficients from Model [1], ratios of slopes from Model [1], or by a reiterative procedure. More sophisticated models based on Model [2], but assuming nonlinear release of organic N, have also been developed along with methods for evaluating the constants involved.
Prediction of Nitrogen Fertilizer Requirements of Field Crops. II. Application of Theoretical Models to Malting Barley1
Authors: Geist J. M. , Reuss J. O. , Johnson D. D.
Published: July 2010

Five indices of soil organic nitrogen availability and mineral plus fertilizer nitrogen were used in the prediction of grain yield, grain protein content, and grain protein nitrogen of Moravian barley. Three mathematical models were employed, one of which included only soil mineral plus fertilizer N for prediction of crop parameters. The remianing two models, which included both organic and mineral plus fertilizer N showed improved predictability of crop parameters. No organic nitrogen measure showed superiority to others, however, one equation model was advantageous in studying the relative contribution of soil organic N to crop production.
Effect of Seedbed Preparations and Green Manure Crops on Corn (Zea mays) Production1
Authors: Beaty E. R. , Giddens Joel
Published: July 2010

Four cover crop treatments consisting of (A) fallow, (B) rye, (C) crimson clover, and (D) rye and crimson clover were seeded to corn on seedbeds prepared by (a) conventional plowing and disking, (b) disking, (c) remove cover crops‐direct seed, (d) cover crop mulched‐direct seed and (e) plant‐mulch cover crop. Corn yields ranged from 4,638 kg/ha on fallow soil to 4,912 kg/ha following crimson clover. Corn yields varied from 4,510 kg to 5,005 kg/ha with different seedbed preparations. The plowed and disked seedbed produced the highest corn yield followed closely by the disked and mulched‐planted seedbeds. Seedbeds where the green manure crop was removed before planting or mulched after planting produced the lowest average yields.

In Georgia green manure crops and seedbeds appear to contribute little to corn production that cannot be obtained by application of commercial fertilizers, and the use of green manure crops would depend upon secondary use of the cover crop.
Jaw‐Action Soil Crusher1
Authors: Reisenauer H. M. , Willett Norman F.
Published: July 2010

A jaw‐action soil crusher is described that crushes and screens soil with minimum contamination, dust production, and operator effort. The machine is suited to samples of greater than 1 liter volume and yields up to 10 kg of 11‐mm mesh soil, or lesser amounts of finer soil, per minute.
Effect of Placement of Phosphorus and Lime on the Growth of a Ladino Clover‐Orchardgrass Sward1
Authors: Woodhouse W. W.
Published: July 2010

High exchangeable Al in subsoils has been suspected as a cause of limited persistence of ladino clover on some soils of the Southeast. The effect on a ladino‐orchardgrass sward of rather thorough incorporation of P and limestone into one such soil was studied. Mixing was by means of a rototiller, one furrow at a time, and extended as deep as 45 cm, compared with broadcast application, followed by disking to 15 cm. Two levels of each material were used, the soil test suggested level and 3 times the soil test level. Deep incorporation resulted in no detectable benefit with either material, and appeared to reduce residual P. Subsoil Al was sharply reduced by liming, but it appeared that mixing to a depth of 15 cm was adequate for these plants on this soil.
Expected Yields and Returns for Corn Due to Nitrogen and Plant Population1
Authors: Colyer Dale , Kroth Earl M.
Published: July 2010

Expected corn (Zea mays L.) yields, net returns, and variances have been calculated from predicted yield data based on regression analysis of nitrogen and population experiments for 7‐ and 8‐year periods in Missouri. Data from non‐irrigated and irrigated experiments are used for comparative purposes. The pattern of expected yields and returns was similar for the two sets of data although maximum yields and returns for the irrigated plots were greater and were obtained at greater input levels for both nitrogen and population. However, variance patterns, which result from different levels of nitrogen use, were quite disimilar. Variance generally increased with larger N inputs for the non‐irrigated experiment but decreased for the irrigated site. Variances tended to reach a maximum (non‐irrigated) or minimum (irrigated) at about the peak of expected yields.