bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Composition and In Vitro Digestibility of Vertical Layers of Coastal Bermudagrass (Cynodon dactylon L.)1
Authors: Wilkinson S. R. , Adams W. E. , Jackson W. A.
Published: July 2010

Coastal bermudagrass, fertilized at two levels (224‐98‐112 and 1,120‐98‐560 kg N‐P‐K/ha) was clipped at 6‐week intervals and separated into six vertical layers. Each layer was assayed for dry matter (DM), cell wall constituents (CWC), acid‐detergent fiber (ADF), acid‐detergent lignin (ADL), and in vitro digestibility for three harvests during 1965. One harvest was assayed for crude protein (CP) content. In vitro digestibility increased from basal to top layers. Associated with this increase were lower ADL and ADF and small decreases in CWC. Fertility level did not significantly influence ADL or ADF content of vertical layers, however, lower CWC in the top layers at the high fertility level was observed. Increased in vitro digestibility associated with the high fertility level was considered a result of the greater protein content of the forage. Although “quality” as indicated by chemical composition and in vitro digestibility was greater in the upper layers, the high proportion of dry‐matter yield in the lower layers indicates that more total nutrients were present in the basal layers of the sward.
Response of Nodulated and Nonnodulated Soybean Seedlings to Sulfur Nutrition1
Authors: Wooding Frank J. , Paulsen Gary M. , Murphy Larry S.
Published: July 2010

Sulfur deficiency decreased growth and concentrations of nonsoluble N and soluble protein N, increased concentrations of nonprotein N and free amino acids, and had little effect on nitrate N in soybean seedlings. Amide N concentration increased and nitrate reductase activity decreased only in S‐deficient nonnodulated seedlings grown with nitrate N source. Ammonia N concentration increased only in S‐deficient nodulated seedlings grown without an available N source. Nodule hemoglobin concentration was affected little, but nodule quantity and total N2 fixed were decreased markedly by S deficiency. The capacity of soybean seedlings to fix N2 was less than their ability to utilize nitrate N.
Oxygen Diffusion in the Soil‐Plant System IV. Oxygen Concentration Profiles, Respiration Rates, and Radial Oxygen Losses Predicted for Rice Roots1
Authors: Luxmoore R. J. , Stolzy L. H. , Letey J.
Published: July 2010

Oxygen concentration profiles, mean respiration rates, and the percent radial oxygen losses (proportion of the oxygen diffusing into the top of the root that is lost radially from the root) were obtained from an analysis of steady state oxygen diffusion in rice (Oryza sativa L.) root models under simulated paddy field conditions.

An increase in root radius and water layer thickness results in an increase in the oxygen concentration within the root and at the root wall at all positions along the root. These higher oxygen concentrations resulted in higher mean respiration rates, however the percent radial oxygen loss (PRL) was reduced. The mean respiration rate and PRL were both decreased with increase in root length. Under paddy conditions it seems that oxygen concentration is a factor limiting respiration rate since the mean respiration rate is much less than the maximum rate for mature root tissue. A 20‐cm root with 0.05‐cm radius is predicted to radially lose about 5 to 7% of the oxygen diffusing into the top of the root. This has considerable ecological significance for roots growing in an anaerobic medium.
Toxicity of Preplant Anhydrous Ammonia to Germination and Early Growth of Corn: II. Laboratory Studies1
Authors: Colliver G. W. , Welch L. F.
Published: July 2010

Laboratory experiments were conducted to determine concentrations of NH3 in soil which are toxic to germination and early root growth of corn (Zea mays L.). In one experiment seeds were germinated in soil uniformly mixed with a given rate of anhydrous ammonia, and in another experiment roots were grown into successive layers of soil containing increasing amounts of NH3. Germination and early growth was retarded when soil [NH3 + NH4+)‐N concentration reached 944 ppm (pH 3.1) and essentially completely inhibited when it reached 1,628 ppm (pH 9.0). Roots grew through 3‐cm layers of soil containing 1,172 ppm (NH3 + NH4 +)‐N (pH 8.4), but did not grow into layers containing 1485 ppm (NH3 + NH4+)‐N (pH 8.7). Radicles stunted by NH3 were thicker and had more branching than those of control plants. Root tips which encountered toxic amounts of NH3 had a brown, scorched appearance.
Number of Replications for Precise Estimation of Optimum Plant Density and Maximum Corn Yield1
Authors: Carmer S. G.
Published: July 2010

The precision of estimates of A and K in the exponential regression model, Y = NAKN + error, relating corn (Zea mays) yield to plant density, and the precision of estimates of optimum density and maximum yield are influenced by the particular set of densities employed in an experiment. A procedure for determining the number of replications necessary to provide reasonable confidence of obtaining precise estimates is outlined, and two illustrative examples are given.
Digestible Dry Matter, Crude Protein, and Dry Matter Yields of Grazing‐Type Sorghum Cultivars as Affected by Harvest Frequency1
Authors: Wedin W. F.
Published: July 2010

‘Piper’ sudangrass, a sudangrass hybrid ‘Trudan II,’ and six sorghum ✕ sudangrass hybrids were variously managed in 1965 and 1966 to provide yield and compositional data. At heights of 46 cm (management A), five harvests resulted; at 92 cm (B), three harvests; at 137 cm (C), two harvests; and hard dough (D), one harvest. Percentages of crude protein and in vitro digestible dry matter (IVDDM) were highest for frequently harvested forage. Yields of dry matter, crude protein, and IVDDM were 27, 10, and 22% greater, respectively, for A (5 harvests) over B (3 harvests). Comparing B to C (3 to 2 harvests) total crude protein yields decreased 4% but dry matter and IVDDM yields increased 23 and 18%, respectively. From C to B (2 to 1 harvest) yields of dry matter, crude protein, and IVDDM were 86% more, 17% less, and 52% more, respectively. Piper was generally inferior to either Trudan II or one or more of the sorghum ✕ sudangrass hybrids. Trudan II was significantly higher yielding in dry matter, crude protein, and IVDDM over all managements as compared to Piper.

Over all managements, Trudan II was significantly higher in crude protein yield than the mean of six sorghum ✕ sudangrass hybrids whereas differences in yields of dry matter and IVDDM were not significant. Sorghum ✕ sudangrass hybrids were definitely superior under D (1 harvest) management. While the sorghum ✕ sudangrass hybrids and Trudan II were both superior to Piper under multiple harvest (A,B,C managements), the sudangrass hybrid (Trudan II) should be given strong consideration because of its known advantage in lower prussic acid potential.
Influence of Dicamba on the Growth and Development of Grain Sorghum1
Authors: Pepper Thomas F. , Weibel Dale E. , Santelmann P. W.
Published: July 2010

Experiments were conducted in the field and greenhouse to determine the responses of grain sorghum to 3,6‐dichloro‐o‐anisic acid (dicamba). Plants were treated on different segments of the plant and at different growth stages. The influence of dicamba on floral development was also studied. Treatment of 2‐ to 3‐week‐old plants delayed maturity and reduced sorghum height. Varietal differences in dicamba susceptibility occurred, with two of seven varieties not producing seed after treatment. Soil treatments caused more injury than foliar applications. Treatments when the plants were 40 days old reduced yield. Treatments after head emergence caused increased lodging and sometimes resulted in head damage at anthesis. When applied to the 12th leaf of flowering plants, radioactive dicamba was found to translocate readily and to accumulate in the floral organs. Treatment of A‐ and B‐line sorghum indicated that dicamba did not affect pollen production or viability. However, the female flower organs were affected.
Effect of Ferrous Sulfate and Sulfuric Acid on Grain Sorghum Yields1
Authors: Mathers Aubra C.
Published: July 2010

Sulfuric acid and ferrous sulfate treatnients of calcareous soil increased yields of hybrid grain sorghum grown in the greenhouse. Effects of 250 ppm or more Fe with 250 ppm or more H2SO4 were still significant on the third crop after soil treatments were made. This study shows that residual effects are possible from heavy applications of FeSO4and H2SO4.

In a field experiment, 560 kg/ha iron as FeSO4 or 560 kg/ha of H2SO4 produced about the same yield response on calcareous Arch Fine sandy loam.
The Statistics‐Computer Interface in Agronomic Research1
Authors: Cady F. B. , Fuller W. A.
Published: July 2010

Research situations which fall into one of two broad classifications: (1) those which can be managed without the computer but less efficiently and (2) those which can not be managed without a computer, are emphasized through utilization of existing programs. The Statistics‐Computer interface is focused on experimental situations through a general linear (least squares) model program. These least squares programs are being developed for a wide class of data processing problems, including the capacity to handle more complete analyses of variance. In addition to data processing, experimenters can use computers efficiently in other phases of agronomic research, e.g., literature searching, planning of experiments, simulation, and data storage and retrieval.
Effect of N, P, and K Tissue Levels and Late Fall Fertilization on the Cold Hardiness of Tifgreen Bermudagrass (Cynodon dactylon X C. transvaalensis1
Authors: Reeves Sim A. , McBee George G. , Bloodworth M. E.
Published: July 2010

Tifgreen bermudagrass grown under different nutrient treatments in a greenhouse and artificially frozen in a growth chamber showed that nutrient level has some effect on winter hardiness. The nutrient treatment levels did not seem to vary the temperature range required for killing the grass over the range of 1 to 3 C. Within this range, the P/K ratio in the tissue appeared to influence cold hardiness. A high P/K ratio increased winterkill whereas low ratios showed little damage. Tissue N levels showed little effect on winterkill but seemed to influence uptake of P and K.

N, P, and K were applied at the rate of 1.47 kg/100m2 per month through December 1967 to Tifgreen bermudagrass under field conditions at College Station, Texas. With a low temperature of ‐8 C there was no winter‐kill of grass from any treatment. Plots receiving late applications of N remained green longer in the fall and were the first to recover in the spring.

Under greenhouse conditions as well as in the field the tissue content of P and K tended to increase as the N level increased. Chemical analysis of grass samples collected from the various treatments showed a direct relationship between tissue content of N‐K and N‐P.
Four‐terminal Peltier Type Thermocouple Psychrometer for Measuring Water Potential in Nonisothermal Systems1
Authors: Millar A. A. , Lang A. R. G. , Gardner W. R.
Published: July 2010

The construction, calibration, and tests of a miniature four‐terminal thermocouple psychrometer are described. Improved thermal stability under nonisothermal conditions is the main feature of this new type of psychrometer. This is achieved using a separate thermocouple to cool and condense water vapor on the sensing thermocouple.

The sensitivity for this thermocouple psychrometer is about 0.4 μv/bar ‐ at 25C, and is operable at temperature fluctuations of about 0.5C during the course of a measurement.

In situ measurements of water potential in onion leaves under a cloudy day differed by 0.5 to 1 bar from measurements on detached leaves. With greater temperature fluctuations, water potentials obtained by the two methods differed by as much as 2 to 3 bars.
Yield and Quality of Different Vertical Layers of a Tall Fescue Sward1
Authors: Burns Robert E.
Published: July 2010

A tall fescue (Festuca arundinacea Schreb.) sward was mowed to a stubble height of 5 or 10 cm when it had attained various heights to determine the effect of these two factors on yield. To determine the vertical location of the growth in the sward, sucessive layers were harvested from 7.5 cm to the ground level. Yield of forage was affected by forage height when cut rather than by stubble height; the higher the grass was permitted to grow before each clipping the more forage produced per year. Approximately 65% of the dry matter was found below the 5‐cm level. The in vitro DMD of this forage was 30% compared to 60% for the higher layers. Ash content was not high enough from any layer to affect yield or forage quality.
Dryland Evaporative Flux in a Subhumid Climate: II. Plant Influences1
Authors: Ritchie Joe T. , Burnett Earl
Published: July 2010

Seasonal variation in three plant factors and in evaporation rates were determined for dryland cotton and grain sorghum in central Texas. Plant factors measured were fractional ground cover, dry matter production, and leaf area index (LAI). When an adequate supply of soil water was available in the rhizosphere, plant factors influenced evaporation rates during most of the first half of the groiwng season until a “threshold” canopy LAI was obtained. A threshold canopy LAI is defined as the minumum LAI necessary to obtain 90% of potential evaporation (Eo) from row crops when the soil evaporation (Es) is small. The threshold LAI was approximately 2.7 for both crops studied. After the threshold canopy LAI was obtained, evaporation was practically independent of plant factors and equal to Eo, as estimated from daily net radiation, until soil water movement to plant roots began to limit evaporation.

Es strongly influenced the actual evaporation rates obtained when plant canopy LAIs were below 2.7, To evaluate the influence of plant factors on the resulting plant evaporation (Ep) independent of Es, it was necessary to attempt a rational separation of Es, and Ep. Es was assumed to be equal to the net radiation equivalent of evaporation below the plant canopy when the soil surface was wet. After the soil surface dried sufficiently to limit water movement to the surface, Es was estimated from the measured soil water content near the surface. Ep was estimated using the measured evaporation and Es. The ratio Ep/Eo was found to be related to the LAI according to the equation

Ep/Eo = −0.21 + 0.70 LAI1/2, 0.1 ≤ LAI ≤ 2.7

This nonlinear relation indicates that Ep is larger per unit of leaf area for smaller plants than for larger plants with LAIs approaching 2.7. Sensible heat originating over partially dry surface soil between plant rows was a significant source of the total energy contributing to Ep

The physiological stage of growth did not greatly influence the amount of energy used in evaporation as grain sorghum plants approached maturity when an adequate supply of soil water was available.

The results imply a possibility for improving water‐use efficiency of dryland crops by using higher plant populations and closer row spacings to decrease Es if the soil water supply and seasonal rainfall is adequate to produce an economic yield.
Spectral Properties of Soybean Leaves1
Authors: Gupta Ram K. , Woolley Joseph T.
Published: July 2010

Light transmission and reflection by leaves are dependent on leaf pigmentation, morphology, and internal structure, all of which may be different in different ages and varieties of soybean leaves. These differences were measured and characterized in the hope that they would prove to be useful in varietal identification by remote sensing techniques.

The reflectance and transmittance of three varieties of soybean leaves were measured over a wavelength range from 500 to 2500 nm using a ratio recording spectroreflectometer. Spectral characteristics of soybean leaves as affected by leaf age were determined. Reflection and absorption of light incident on the upper surfaces (faces) were compared with that of the lower surfaces (backs) of the same leaves. The spectral characteristics of three varieties of soybeans did not differ very much except in the visible region of the spectrum studied. Relatively young leaves reflected more than did old leaves of the same variety in the visible. This was associated with the chlorophyll development. The upper surface reflected less than did the lower surface of the same leaves in the visible region. Such differences were explained on the basis of internal leaf structure and composition.

Although the spectral properties of the three soybean varieties have been established, it was not possible to make varietal identification on the basis of the spectral qualities.
Late Spring Applications of Nitrogen for Efficient Utilization and Enhanced Production of Grain and Grain Protein of Wheat1
Authors: Hucklesby D. P. , Brown C. M. , Howell S. E. , Hageman R. H.
Published: July 2010

Applications of 56 and 112 kg N ha‐1 (as KNO3) on April 2 and 23 and May 9 and 224 kg N ha‐1 on April 23 to Arthur and Blueboy (soft red winter) and Parker (hard red winter) wheats increased yield of grain, grain protein and grain protein percentage without exception. The average increases for all treatments and varieties for grain yield, grain protein and percentage grain protein were 21, 63 and 36% over the respective control values. Based only on amino acid composition, quality of the grains was unaffected by the nitrogen treatments. Depletion of soil nitrogen estimated by removal of grain alone for all varieties occurred not only in the control plots but in plots receiving 56 and 112 kg N ha‐1. Only the 224 kg N ha‐1 treatment plots gave an estimated net gain in soil nitrogen.

The favorable results obtained for grain and grain protein production, the increasing availability of lodgeresistant wheats, and the concern over nitrate pollution of ground water and streams, all indicate that the practice of split applications of nitrogen made late in the spring to wheat has merit.
Quantitative Effects of Nitrogen Fertilizer on the Development and Downward Movement of Soil Acidity in Relation to Level of Fertilization and Crop Removal in a Continuous Corn Cropping System1
Authors: Pierre W. H. , Webb J. R. , Shrader W. D.
Published: July 2010

The effect of NH4NO3 in a continuous corn cropping system on the depth distribution and amount of soil acidity produced was studied on four medium‐acid, prairie‐derived soils. To avoid the confounding effect of soluble salts, pH determinations were made after preliminary leaching of the soils and also by the 0.01 M CaC12 method. The amounts of acidity were measured by determining the quantities of CaCO3 required to bring the N‐treated plots to the pH of the No‐N plots.

With amounts of N ranging from 1,525 to 2,626 kg N/ha no pH changes were found below the 15‐25‐cm layer. However, after a total of 5,600 kg N/ha had been used within 5 years pH changes were found at a depth of 30 to 45 cm.

The total amount of acidity developed averaged 35% of the theoretical (3.57 kg CaCO3 per kilogram N) in the three experiments that received N ranging from a total of 1,525 to 2,626 kg N/ha over 13 to 15 years. In the experiment where 1,120 kg N/ha were used annually, the acidity developed was 60% of theoretical. This larger amount of acidity developed per unit of N with excessive N applications is explained by the lower percentage of fertilizer N recovered by the crop and the higher percentage remaining in the soil or leached as nitrates.

With all additions of N, the development of much less than the theoretical amount of acidity is explained in part by the low excess base compared with N in the corn grain and cobs harvested. It is also, evidently, due to relatively large losses of N from the soil without an equivalent loss of bases, and it seems likely that such losses are due largely to denitrification.
Response of Corn to Small Amounts of Fertilizer Placed with the Seed: I. Greenhouse Studies1
Authors: Miller M. H. , Bates T. E. , Singh D. , Baweja A. S.
Published: July 2010

The effects of a complete NPK fertilizer banded with the seed of corn (Zea mays L.) were compared with those of larger amounts banded 3.8 cm to the side and below the seed. With the side band there was little uptake of applied P at the fourth week after seeding, and differences in growth favoured fertilizer with the seed up to the seventh week. Distance from the seed and toxicity of the higher fertilizer concentrations in the side band are suggested as reasons for the difference.

Potassium banded with the seed added to the response obtained with N and P in one out of three trials. A small percentage of K is believed desirable in fertilizer applied with the seed, except on high‐K soils.

When fertilizer was sprayed on the seed only, the response was small compared to that with the same concentration sprayed in a band across the seed and soil. Considering the small amount of fertilizer on the seed, the response was large, however, and leads to speculation on the effect of coating seed with fertilize.

When a 6‐10.5‐5 fertilizer was banded with the seed at rates above 56 kg/ha in 91‐cm rows, there was an appreciable delay in emergence. The main advantage from fertilizer with the seed is the early growth response. High rates which delay emergence would therefore cancel the advantages which have been demonstrated.
Response of Corn to Small Amounts of Fertilizer Placed with the Seed: II. Summary of 22 Field Trials1
Authors: Bates T. E.
Published: July 2010

Fertilizer was banded with the seed of corn (Zea mays L.) at rates supplying 3.1, 5.4, and 2.5 g N, P, and per K meter of row, respectively, in 22 field trials. Fertilizer with the seed delayed and reduced emergence in several trials. On the average, it increased the dry weight of 36‐day‐old plants 36%, decreased the time to silking by 1.2 days, decreased the ear moisture at harvest 1.2% and increased grain yield 2.9%. A significant yield decrease due to fertilizer with the seed was observed in two trials. Fertilizer with the seed reduced ear node height and, in two trials, plant height. The effect on lodging was variable.
Feeding Corn or Molasses to Cattle on Orchardgrass Pasture1
Authors: Hart Richard H. , Bond James , Carlson G. E. , Rumsey T. R.
Published: July 2010

Cattle grazing an orchardgrass (Dactylis glomerata L.) pasture were self‐fed corn plus fat, molasses plus urea, or no supplement, at three stocking rates within each supplement treatment. Forage availability, supplement consumption, and the interaction between them accounted for 87% of the variability in ADG. Gain/ha increased linearly with stocking rate, until stocking rate became too high to permit grazing all season. Molasses increased ADG and gain/ha, and corn increased these still more. Supplements increased slaughter and carcass grades, overall meat desirability, and all components of desirability except color. Supplement will increase return to land, labor, and management, unless beef prices are unusually low and supplement prices are unusually high; feeding corn will usually be more profitable than feeding molasses.
Influence of Growth Stage and Stubble Height on Herbage Yields and Persistence of Smooth Bromegrass and Timothy1
Authors: Knievel Daniel P. , Jacques Aino V. A. , Smith Dale
Published: July 2010

Although it is generally accepted that time of cutting and height of cutting are important in yield and persistance of forage grasses, studies of their interaction have produced variable results. Differences in environmental conditions (e.g., temperature and moisture) among field investigations could be responsible for this variability. Smooth bromegrass and timothy were harvested at three growth stages and two cutting heights in the field. Timothy was grown at warm and cool temperatures in the growth chamber and harvested at five growth stages and two cutting heights.

Highest seasonal herbage yields and stand persistence of smooth bromegrass (Bromus inermis Leyss.) and timothy (Phleum pratense L.) in the field were obtained when the first crop was cut at early anthesis. Stand persistence was not affected by stubble height when both grasses were cut at early anthesis. Seasonal herbage yields were higher with a 4‐cm than with a 10‐cm stubble height. Bromegrass was more productive and persistent than timothy over the entire experimental period. Very few weeds occurred in the bromegrass during 1967 and 1968, and in the timothy during 1967. In 1968, timothy stands cut at early anthesis contained only 1 to 2% of weeds, but there were 6 to 15% in treatments cut at the tillering or inflorescence emergence stages.

Highest herbage growth rate (HGR) and tillering rate of timothy in the growth chamber occurred with cutting at an early leafy stage or at early anthesis at both cool (18 C day/10 C night) and warm (32 C day/24 C night) temperatures. Lowest HGR occurred with cutting at midstem elongation and inflorescence emergence. Warm temperatures significantly reduced HGR and tillering rates at all growth stages and stubble heights. Cutting at a 4‐cm compared with a 12‐cm stubble height significantly lowered HGR at almost all growth stages at warm temperatures, but only at the tillering stage at cool temperatures. These results indicate that the yield and stand persistance response of cool‐season grasses to growth stage at cutting and height of cutting is partially dependent on temperature before and after cutting.
Effects of Soil Temperature Regimes on Growth Characteristics, Nutrition, and Grain Yield of IR22 Rice1
Authors: Bhattacharyya A. K. , De Datta S. K.
Published: July 2010

The effects of soil and water temepratures of 15, 25 and 35 C on the growth, nutrition, and grain yield of rice (Oryza sativa L.) were studied at three stages of growth in the greenhouse. The dwarf variety IR22 was used as the test plant. Plants grown at greenhouse temperature were used as the control.

Low temperatures at the early vegetative stage retarded the growth of shoots and roots. Compared with the control, higher soil temperatures accelerated the growth and development of the plants. A temperature of 15 C delayed panicle initiation by 17 days and extended the time required for complete heading. Crop maturity was proportionately delayed. Soil temperatures during the early vegetative growth stage had little effect on the concentration of N, P, K and Si in plant tissues. Grain yields were unaffected by the temperature treatments at this stage.

The plants were highly sensitive to cool soil and water temperatures during panicle development. Low soil temperature caused the death of lower leaves and chlorosis of the upper leaves, and both vegetative growth and dry matter production were retarded. Heading was also delayed at the low temperature and it took longer for all the panicles to emerge. Furthermore, fewer spikelets were formed and injury to some of them was observed. Dry matter production was highest at 25 and 35 C during panicle development. Grain yields were significantly decreased by a soil temperature at 15 C during this period.

Plant growth and grain yields were least affected by low soil and water temperatures during the period from heading to crop maturity.
Age Effects of Cotton Leaves on Light Reflectance, Transmittance, and Absorptance and on Water Content and Thickness1
Authors: Gausman H. W. , Allen W. A. , Escobar D. E. , Rodriguez R. R. , Cardenas R.
Published: July 2010

Cotton plants (Gossypium hirsutum L.) were grown in the growth chamber, greenhouse, and field to study effects of leaf maturation on spectral properties, water content, and thickness of single leaves.

In the 500‐ to 750‐nm region and at 1,650 and 2,200 nm, leaf age had a variable effect on reflectance. Over the 750‐ to 1,350‐nm wavelength interval (WLI), leaf reflectance was a maximum at node 8, and gradually decreased from node 8 to node 13.

At the 1000‐nm wavelength, greenhouse‐ and field‐grown leaves had reflectances of approximately 51.0% compared with 46.0% for growth chamber‐grown leaves. For all environments middle‐aged leaves had highest reflectances.

Field‐ and growth chamber‐grown leaves of all nodes except 3 from the apex had higher absorptance at the 550‐nm wavelength than greenhouse‐grown leaves. Middle‐aged leaves from all three environments had maximum absorptance.

Greenhouse‐grown leaves had approximately two to four times higher absorptance at the 1000‐nm wavelength than field‐ and growth chamber‐grown leaves. For greenhouse leaves, absorptance was least at node 8. Leaf age had little influence on absorptance of field‐ and growth chamber‐grown leaves.

Growth chamber‐grown leaves had the highest and fieldgrown leaves the lowest water content. In the growth chamber and field, leaf water content increased with leaf age.

Leaf thickness generally increased with leaf maturation in all three environments, but growth chamber‐grown leaves were thinnest.

Because growth chamber‐grown plants developed shadetype leaves, measurements on these leaves differed markdly from measurements made on leaves of field‐ and greenhouse‐grown plants. Thus growth chamber results should not be extrapolated to field conditions, unless it is known that the environmental conditions in the growth chamber closely simulate field conditions.
Advection and Evapotranspiration of Wide‐Row Sorghum in the Central Great Plains1
Authors: Hanks R. J. , Allen L. H. , Gardner H. R.
Published: July 2010

This study was conducted to evaluate the importance of advection as a source of energy for evapotranspiration from grain sorghum planted in 1‐m rows with both irrigated and dryland conditions. Detailed measurements of temperature, water vapor content, and wind speed were made within and above the canopy at various times and positions within the field during August 1967. Evapotranspiration was also measured by soil moisture sampling. Three types of advection were observed. Withincanopy advection resulted from the large amount of exposed dry soil between rows, which caused soil temperature between the rows to be as much as 20 C higher than plant temeprature. About 64% of the energy used to heat up the soil was used for transpiration in the irrigated plot, whereas only about 21% of the energy was used for transpiration in the dryland plot. Border advection, manifested by horizontal temperature and water vapor gradients, occurred over most of the plot irrigated but was most evident from 0 to 40 m from the upwind edge. This type of advection yielded sufficient energy to account for about 30% of the energy used for evapotranspiration from the irrigated plot. Large scale advection, manifested by temperature inversions, was found to occur during the night and probably yielded very little energy used for evapotranspiartion.
Influence of Fertility Ratios on Winter Hardiness of Bermudagrass1
Authors: Gilbert W. B. , Davis D. L.
Published: July 2010

The influence of different ratios of nitrogen, phosphorus, and potassium on cold tolerance of two golf‐green bermudagrass (Cynodon spp.) cultivars was investigated. Samples from field‐produced turf were depleted of soil nutrients before the fertility ratios were applied, then cold‐hardened in a growth chamber prior to being subjected to a standard freezing test. Significant differences occurred among several ratios in the amount of regrowth obtained in the greenhouse following freezing. Differences among treatments became greater with the decrease in tmperature. Ratios in which the levels of nitrogen and potassium were approximately equal and about 4 to 5 times greater than phosphorus gave the greater quantities of regrowth. Inferior treatments were those with higher amounts of nitrogen in relation to the other two nutrients. Of those tested, it was found that a ratio of 4‐1‐6 was superior in producing cold tolerance. These results indicate that a balanced fertility program with emphasis on adequate potassium in late summer would improve the cold resistance of the two bermudagrasses.
Effect of Gypsum and Drought Stress on Maize (Zea mays L). II. Consumptive Use of Water1
Authors: Downey Lloyd A.
Published: July 2010

The effect of three defined periods of drought stress on the consumptive use of water by field grown maize (Zea mays L.) was measured using a complete water balance approach. Water status within the crop was defined by noon measurements of relative turgidity (RT). The treatments were set out in a randomised block design with a further comparison between the untreated (sodic) soil and the same soil treated with gypsum at 22.4 m tons ha−1.

The components of the water balance — soil stored moisture, rain, and applied irrigation — were measured directly, and deep drainage was calculated from chloride redistribution. The no‐stress treatment (RT at noon maintained > 90%) used 59 cm in evapotranspiration during the growing period. Drought stress (RT at noon < 90%) for a period of 20 days during male meiosis (early stress) reduced this total evapotranspiration to 44 cm, while drought stress during grain filling (late stress) reduced it to 51 cm. The application of gypsum had no significant effect on water use nor on water entry at irrigation.

Application efficiency (total evapotranspiration/total applied water) was 86%, 79%, and 85% on the no‐stress, early‐stress, and late‐stress treatments respectively. The balance (15 to 20%) of applied water was lost as deep drainage, indicating that results on more permeable soils would be inaccurate if this component were ignored.

Maximum water use of 0.9 cm day−1 (or 0.8 of class “A” pan) occurred during anthesis. This period was delayed 10 days by early stress. Water use efficiency was highest for the early stress‐87 kg dry grain/cm water/ha and lowest for the late stress‐26kg.
Light Intensity and Sunfleck‐size Distributions in Plant Canopies1
Authors: Norman J. M. , Miller E. E. , Tanner C. B.
Published: July 2010

A theory predicting the gap‐size distribution of a canopy of horizontal, azimuthally symmetric, randomly located, flat leaves of any shape is compared to measurements in sumac (Rhus typhina L.), sunflower (Helianthus annuus L.), and an artificial canopy. Light intensity distributions of the solar beam component on a horizontal surface below these canopies are predicted by combining the gap‐size distribution theory with penumbral effects of the finite solar disc. These predictions of the beamcomponent distribution are then combined with average diffuse penetration theory and a new scattering theory to produce a final light intensity distribution for comparison with measurements from a miniature light sensor in visible and near‐infrared wavelength bands. The agreement is good and indicates that sizable penumbra effects occur in canopies only 2 m in height.
Factors Affecting the Development of Flue‐Cured Tobacco Grown in Artificial Environments. III. Morphological Behavior of Leaves in Simulated Temperature, Light‐Duration, and Nutrition Progressions During Growth1
Authors: Raper C. D.
Published: July 2010

The growth environment of a plant determines the ultimate expression of many characteristics of development. Among other environmental variables, a plant growing in the field encounters seasonal progressions of temperature, daylength, and nutrient supply. To determine if these natural, seasonal progressions are essential for reproducing “normal” field growth of flue‐cured tobacco (Nicotiana tabacurn L. ‘Coker 319’) in controlled‐enviromnent facilities, simplified simulations of temperature, light‐duration, and nitrogen and potassium nutrition were established in controlled‐enviromnent rooms. Regression‐descriptors plots of regression equations with leaf‐stalk position as the independent variable) of size, shape, and specific weight of mature leaves from plants grown under combinations of these simulated progressions and constant temperature, light‐duration, and nutrition regimes were evaluated relative to characteristic regression‐descriptors derived from field grown plants.

A seasonal progression of temperature and progressive reductions of nitrogen and potassimn supply are critically involved in determining the physical attributes of leaves characteristic of “normal”, field‐grown tobacco. Combined with a continuous daily light‐duration of 9 hours, the simulated progressions of temperature and nutrition most nearly facsimilated a “normal” leaf‐size ordering and resulted in the least disruption of “normal” variations of leaf shape and specific leaf weight due to stalk position.
Cumulative Effects of Cutting Management on Forage Yields and Tiller Densities of Tall Fescue and Orchardgrass1
Authors: Hart Richard H. , Carlson G. E. , McCloud D. E.
Published: July 2010

When tall fescue (Festuca arundinacea Schreb.) and orchardgrass (Dactylis glomerata L.) were cut each week after the first harvest, forage yields before flowering increased when first harvest was delayed and decreased as stubble height increased. Neither stubble height nor time of first harvest affected yields after flowering in the 1st harvest year. In the 2nd and 3rd years, yields after flowering decreased as stubble height increased. In the 3rd year they also decreased when the first harvest was delayed, so much that total forage yields were similar for all dates of first harvest, even though preflowering yields differed. The decrease in post‐flowering yield was associated with a decrease in stand density. Although increased stubble height decreased total forage yields, it increased yields of forage plus stubble, indicating higher total dry‐matter production. However, production was still higher when the grasses were cut closely every month instead of every week. This treatment gave the maximum forage production, because less of the total production was left as stubble.
Rooting of Poa annua L., Poa pratensis L., and Agrostis palustris Huds. at Three Soil Bulk Densities1
Authors: Wilkinson James F. , Duff D. Thomas
Published: July 2010

Poa annua L. is usually considered an inherently shallow‐rooted grass. A growth‐chamber study was designed to compare the rooting of P. annua, P. pratensis L., and A. palustris Huds. at bulk densities of 1.1, 1.25, and 1.4. Treatments included P. annua and P. pratensis cut at 3.8 cm, and P. annua and A. palustris cut at 1.3 cm. Root samples were taken at four depths, 8 and 12 weeks after germination. Root weight was determined by weight loss after ashing the samples.

Root weight decreased with depth, but increased with bulk density. Although root weight increased after 12 weeks, there was no significant difference between dates. When grown at the same bulk density, the root growth of all grasses was statistically the same at any given depth.
Effect of Transplanting and Plastic Cover on Growth of Sugar Beets1
Authors: Dillon M. A. , McCaslin B. D. , Schmehl W. R.
Published: July 2010

Two field experiments were conducted to determine the effect of transplanting and plastic cover on the seasonal growth and yield of sugar beets (Beta vulgaris L.). Both transplanting and plastic cover increased leaf areas in June and early July and increased final root yields. Earlier planting also increased early leaf areas and final root yields. The results showed that treatments increasing leaf area in June and early July increased final root yields, but differences in leaf area that occurred in August or later were not associated with differences in yields. Transplanting or plastic cover increased recoverable sucrose production as much as 44 to 48% over the conventionally planted sugar beets in 1968 and 26 to 27% in 1969. The advantages of these practices were greater for April than for May plantings.
Effects of Increasing Amounts of Organic Residues on Continuous Corn: I. Yields and Soil Physical Properties1
Authors: Morachan Y. B. , Moldenhauer W. C. , Larson W. E.
Published: July 2010

When well‐fertilized corn (Zea mays L.) monocultures with large amounts of residues returned to the soil became common, the question was asked as to whether soil tilth and corn yields could be maintained at satisfactory levels in Corn Belt soils. To answer this question corn growth and soil physical properties were determined in a field experiment in which different types (alfalfa (Medicago sativa L.), cornstalks, sawdust, oatstraw (Avena sativa L.) and bromegrass (Bromus inermis Leyss)) and amounts (from 0 to 16 tons/ha/yr) of plant residues were added to Marshall silty clay loam (Typic Hapludoll) for 13 consecutive years. The soil was cropped to corn and large amounts of N were added. For approximately the first 9 years grain yields were lower from the check and sawdust treatments than from all others. During the last 4 years grain yields declined sharply with rate of addition of cornstalk residues and slightly from additions of alfalfa. It is suggested that the yield decline in the cornstalk treatments was due to a lowering of pH and an Al‐induced Ca deficiency in the plant. An alternative explanation is that the cation balance was upset as evidenced by K/Ca and K/Ca + Mg ratios in the plant.

The C content of the soil was progressively increased, as was the wet aggregate stability and water retention with rate of addition of organic material. Energy of aggregate rupture, energy to initial runoff, erosion, and infiltration were not significantly influenced. It was not visually evident that significant changes occurred in soil tilth because of treatment differences.

Marshall soils are well aggregated, have favorable physical and chemical properties, and although erosive, physical problems are not usually observable in the field. Corn grain yields averaged near 7,000 kg/ha (112 bu/acre) in the later years of the experiment, again suggesting that the physical properties of the soil on all treatments were favorable.
Changes in the Concentration of Nitrogenous Fractions in Alfalfa Herbage with Advance in Maturity1
Authors: Lee Chin‐tian , Smith Dale
Published: July 2010

Little information is available in which changes in the concentrations of total, protein, nonprotein, ammonium, nitrate:, free α‐amino, asparagine, and glutamine N in alfalfa (Medicago sativa L.) herbage have been measured at successive growth stages in the same investigation. In the current study, concentrations (% dry weight) of these N fractions were analyzed for the leaflets, stems, and total herbage of ‘Vernal’ alfalfa sampled when the spring growth in 1966 was 25‐, 41‐, and 53‐cm tall, and at first, 25%, and 75% flower.

All N fractions decreased in percentage in the leaflets, stems, and total herbage with advance in maturity. Percentages of total N, protein N, and non‐protein N were higher in the leaflets than stems at all stages of growth, while percentages of ammonium N and glutamine N were similar in leaflets and stems. In contrast, percentages of nitrate N, free a‐amino N, and asparagine N were higher in the stems than leaflets. Percentage decreases in the concentration of N f.ractions in the total herbage from the youngest (25‐cm tall) to the oldest (75% flower) stage ranged from a low of 50% for protein N to a high of 75% for nitrate N.
Dispersion and Deposition of Corn Pollen from Experimental Sources1
Authors: Raynor Gilbert S. , Ogden Eugene C. , Hayes Janet V.
Published: July 2010

The atmospheric dispersion and subsequent deposition of corn (Zea mays L.) pollen emitted from plants in two 18‐m diameter plots were studied in 39 tests at Brookhaven National Laboratory to compare the spread of this large pollen to that of smaller pollens studied previously. Concentrations were measured by wind‐impaction samplers mounted at four heights (0.5 to 4.6 m) and at five distances from the source on 20‐degree radii. Deposition was measured by greased microscope slides on the ground.

Data were analyzed in terms of current meteorological dispersion theory. Normalized centerline concentrations, crosswind integrated concentrations, plume widths and heights, and mass flux are presented as functions of distance and compared to similar data from ragweed (Ambrosia) and timothy (Phleum pratense) sources of comparable size. Normalized centerline and crosswind integrated deposition and velocity of deposition are also presented as functions of distance and are compared to ragweed and timothy pollen data. The study shows that corn pollen is not transported as far by the wind as smaller pollens, does not disperse as widely in either the horizontal or the vertical direction and settles to earth more quickly, much of it within the source itself.

The dispersion of corn pollen is influenced by its large size and rapid settling rate. At 60 m from the source in the downwind direction, concentrations average about 1% of those at 1 m. Width of the pollen plume at 60 m is less than that of smaller pollens under similar conditions. The rate of settling opposes the rate of upward dispersion so that the height of the pollen plume does not increase continuously with downwind distance. At 60 m from the source concentrations integrated in the crosswind direction average from 3 to 6% of those at 1 m. The total amount of pollen remaining airborne at 60 m is 5% of that at 1 m.

Total deposition within the source plot is greater than that outside. Deposition per unit area at 60 m downwind is only 0.2% of that near the source. Crosswind integrated deposition at 60 m varies from 0.5 to 0.8% of that at 1 m. The velocity of deposition at 32 m from the source averages about 33 cm/sec.
Improved Reciprocal Grafting Technique for Soybeans (Glycine max L.)1
Authors: Bezdicek D. F. , Magee B. H. , Schillinger J. A.
Published: July 2010

A technique for reciprocal root‐scion grafting of soybeans is described using plastic straws and small rubber bands in place of pressure tape commonly employed. The technique described is simpler and faster than the pressure‐tape method of grafting; success of greater than 90% was obtained in our experiments.
Laboratory and in vitro Evaluation of Inbred and F2 Populations of Brown Midrib Mutants of Zea mays L.1
Authors: Lechtenberg V. L. , Muller L. D. , Bauman L. F. , Rhykerd C. L. , Barnes R. F.
Published: July 2010

The purpose of this research was to determine the effect of brown midrib mutants on the lignin percentage and in vitro dry matter disappearance (IVDMD) of corn (Zea mays L.) stover. F2 populations of corn carrying the brown midrib mutants bm1, bm2, and bm3, were grown under field conditions and harvested at 35 and 55 days post‐silking. Plants harvested at 35 days post‐silking were separated into several parts. Samples were analyzed for structural composition and in vitro dry matter disappearance using detergent solution and rumen fermentation techniques, respectively. Stover, harvested 55 days postsilking, contained 8.15, 8.07, 4.96, and 8.81% acid detergent lignin for genotypes bm1, bm2, bm3, and F2 normal, respectively. The IVDMD percentages were 49.3, 47.6, 56.3, and 46.2, respectively. At 35 days post‐silking, the lignin content was lower and the IVDMD higher in bm3 than in the other genotypes for all plant parts except the kernel. The structural composition and IVDMD of normal corn was similar to that of a commercial hybrid included in the study.

Mutant inbred lines (Tr background) of bm1, bm3, bm2, bm3, and bm4 were also evaluated. Mutants bm3 and bm1bm3 were lowest in lignin and highest in IVDMD. In both the inbred and F2 populations, structural components other than acid detergent lignin did not differ appreciable among the genotypes.

Since lignin limits the digestion and utilization of fibrous feeds by ruminant animals, the possible use of brown midrib mutants for improving the nutritional quality of corn stover and silage appears promising. Mutant bm3 appears to have the most potential for this purpose.