bluuebunny/crossref_metadata_2025 huggingface dataset:
Technique for Determining Root Elongation Rates through Soil Layers of Different Physical and Chemical Properties1
Authors: Batchelder A. R. , Bouldin D. R.
Published: July 2010

A technique is described for accurately and automatically measuring the rate of root elongation through soil layers having different physical or chemical properties, or both, without disturbing the root system. By utilizing the electrical conductance properties of a root, the time at which the tip of an elongating root penetrates a paraffin‐petrolatum membrane separating two successive soil layers is determined by the resultant changes in electrical resistance between the two soil layers.

The technique was tested in two laboratory experiments with corn (Zea mays L.). In one study the system was used to determine primary root elongation rates through columns of Honeoye silt loam consisting of five layers packed to a bulk density of 1.25 g/cm3 and one layer at 1.40 g/cm3 with a membrane separating each pair of soil layers. In the other study primary roots were allowed to grow in natural subsoil clods for specific times following penetration of the membrane that separated the clod and a layer of topsoil.

Root penetration through the membrane was easily detected and was recorded with an automatic monitoring system. The technique proved to be an efficient, reliable, and sensitive method for determining root elongation rates through soil layers.
Forage Production and Botanical Composition of Mixed Prairie as Influenced by Nitrogen and Phosphorus Fertilization1
Authors: Lorenz Russell J. , Rogler George A.
Published: July 2010

Shortage of available nutrients is limiting productiveness of native range in portions of the northern Great Plains. The demand for increased forage production to support an increasing number of livestock will require use of intensive management practices, including range fertilization.

Response of mixed prairie vegetation to annual applications of 0, 45, 90, and 180 kg elemental N/ha and 0, 20, and 40 kg elemental P/ha was studied over an 8‐year period near Mandan, N. D. At all P levels and for each harvest height used, increase in dry matter production in response to N was highly significant and nearly linear in nature for the 45‐N and 90‐N levels. Harvest at a height of 25 mm on August 1 produced 8‐year average annual dry matter yields of 810, 1,938, 2,960, and 3.097 kg/ha for the 0‐N, 45‐N, 90‐N, and 180‐N levels, respectively. Harvest at the soil surface produced 6‐year average yields of 2,047, 3,035, 3,898, and 4,205 kg/ha for the respective N levels. Response to P was often not significant during the first 3 years of the study; however, ever the 8‐year period, each increment of P produced a significant yield increase. Without N, response to P was small, but as N level increased, response to P increased. Density of western wheatgrass (Agropyron smithii Rydb.) increased and basal cover of blue grama (Bouteloua gracilis [H.B.H.] Lag.) decreased as N level increased under the harvest system used in this study.
Germination and Yield of Barley When Grown in a Water‐Repellent Sand1
Authors: Bond R. D.
Published: July 2010

Uneven penetration of rainwater into water‐repellent sands decreases germination of annual plants. To assess the importance of this problem, germination and yield of barley (Hordeum vulgate cv Prior) were observed at two field sites on water‐repellent sands in South Australia. Germination continued throughout the wet winter period and 9 viable ungerminated seeds were recovered from 60 cm of row 3 month after sowing. Germination was controlled by the uneven penetration of rainwater into the soil.

At Site I, the number of plants 1 month after sowing averaged 1.6/m in the poor plots and 19.2 plants/m in the good plots. Subsequently 11.0 plants/m grew in the poor rows but produced only 150 kg grain/ha compared with 1,440 kg/ha in the good plots while the average yield for this site was 560 kg/ha. Similar results were obtained at Site II where good plots yielded 1,830 kg grain/ha compared with 16 kg/ha in the poorest rows and an average yield for the site of 1,160 kg/ha.

Delayed and incomplete germination of cereals on water‐repellent soil can cause very low grain yields.
Influence of Levels of Spring Irrigation and Fertility on Yield of Winter Wheat (Triticum aestivum L.) under Semi‐arid Conditions1
Authors: Poostchi I. , Rovhani I. , Razmi K.
Published: July 2010

Under semi‐arid conditions of southern Iran variation in moisture level can drastically change yield patterns of winter wheat (Triticum aestivum L.) within the same season or over several seasons. In order to study this yield fluctuation, an experiment considering the effects of spring irrigation and fertility levels on components of yield, plant characteristics, and yield of grain and straw of ‘Roushan’ variety of winter wheat was conducted.

Thiis 3‐year study showed that yields of grain and straw were positively and significantly correlated with levels of irrigation in each crop season and in combined 3 years. The correlations for yield of grain to levels of fertilizer were negative and significant. Multiple and partial correlation coefficients showed components of yield to be more affected by season and irrigation level than other factors under study.
Effect of N, P, and K Fertilization and Stages of Maturity on Chemical Composition of Fiber in Kleingrass (Panicum coloratum L.)1
Authors: Rouquette F. M. , Holt E. C. , Ellis W. C.
Published: July 2010

Studies were conducted to determine the influence of N, P, and K fertilization and different stages of growth on the nutritional quality of kleingrass (Panicum coloratum L.) forage. Nitrogen rates ranged from 28 to 560 kg/ha with additions of 24 and 73 kg/ha P, and 0, 46, and 139 kg/ha K. Leaf‐stem separations were made at each harvest date and cellular (neutral detergent extract; NDE) and cell wall constituents (neutral detergent fiber; NDF) were determined on the plant parts. The NDF fraction was then sequentially partitioned into hemicellulose, cellulose, lignin, and ash. Levels of N or P were significantly negatively correlated with percent NDF of leaf laminae. Chemical components of stem fiber were not altered by fertility levels. On a whole‐plant basis percent NDF was reduced about 5 percentage units by additions of N. Percent NDF in leaves and stems increased with chronological and morphological age. The holocellulose content of leaves remained relatively constant throughout the study period; with advancing maaturity, however, the hemicellulose fraction accounted for a greater portion of the NDF than did cellulose. The hemicellulose:cellulose ratio increased to approximately 1.7:1 in leaves, but remained at 1:1 in stems with increasing maturity. The leaves apparently had more influence on decreasing NDF of the whole plant under fertilization, whereas, stems were the dominant factors involved in increasing NDF of the whole plant with advancing maturity.
Photoperiodism in Sorghum1
Authors: Caddel J. L. , Weibel D. E.
Published: July 2010

Three varieties of Sorghum bicolor (L.) Moench (i.e., ‘Early Hegari,’ ‘80‐Day Milo,’ and ‘Ryer Milo’) were subjected to different treatments of short (10‐hour) and long (17‐hour) days in controlled‐environment chambers. The number of days from planting to floral initiation was determined for each variety in each treatment. The research was conducted to determine the age at which sorghums become sensitive to photoperiod and to estimate the minimum number of inductive cycles required for floral stimulation.

Short days applied after the plants were 15 days of age hastened floral initiation, while long days when the plants were between 15 and 20 days of age delayed initiation. Thus, photopei iodic sensitivity is attained at about 15 days of age. As these varieties increased in age beyond 15 days, less time was required for floral initiation following stimulation. Five short days were sufficient to stimulate floral initiation of plants older than 15 days. Three short days inconsistently hastened floral initiation. A greater number of leaves than the first five were required for photoperiodic induction.
Influence of Nitrogen Source and Rate on Growth of Spring Grain and Soil pH1
Authors: Alessi J. , Powers J. F.
Published: July 2010

The effect of five N sources upon spring grain production was studied on Temvik silt loam for 4 years at Mandan, N. Dak., and residual responses were followed for 4 more years. The five sources—ammonium nitrate, ammonium sulfate, calcium nitrate, Uramite, and Nitroform (urea‐formaldehyde)—were applied at rates of 0, 34, and 68 kg N/ha to spring wheat (Triticum aestivum) or barley (Hordeum vulgare L.). Results suggest that neither the rates of fertilization studied nor the interaction of N carrier × N rate were important in the production of total plant dry weight or grain yield. Small grain production was significantly altered by N source in only one of the fertilization years. Cumulative grain yields for 1960‐1963 were significantly increased by fertilization with nitrate and ammonium sources. Grain yields for the 8‐year period were significantly higher for ammonium and nitrate sources than for urea‐formaldehyde sources. Residual effects from urea‐formaldehyde fertilization were less effective for grain production than residual effects from nitrate and ammonium N carriers. Although ammonium sulphate lowered pH during the fertilization period, grain development was not seriously affected by this acidification. Cumulative grain production for the 8 years was 10,000 kg/ha with no N, 12,470 kg/ha with nitrate ammonium carriers, and 11,530 kg/ha with urea‐formaldehyde sources.
Influence of Certain Rotations upon Cotton Production in the San Joaquin Valley1
Authors: Turner John H. , Smith E. G. , Garber R. H. , Williams W. A. , Yamada H.
Published: July 2010

Cotton (Gossypium hirsutum L.) is the major cash commodity from San Joaquin Valley farms. Frequently, growers plant cotton for 3 to 6 years without rotation. Alfalfa for hay production or grain crops are the main crops planted on land removed from cotton.

Very few rotation studies with cotton have been conducted in the western states. The purpose of this experiment was to determine the effect of certain rotations and N applications on growth and yield of cotton.

Increased yields were obtained for cotton following alfalfa (Medicago sativa L.) and cotton following corn (Zea mays L.) over the continuous cotton plots. No advantage for yield was shown between cotton following corn and cotton following alfalfa. Nitrogen fertilization increased yields of continuous cotton, of cotton following corn, and of cotton the 2nd year following alfalfa, but not of cotton the 1st year after alfalfa.

Water infiltration data showed that a significant reduction of water intake occurred on the N subplots compared to those with no N.

Plant heights were significantly different at first‐bloom stage for both the rotation and the N treatments. Final plant height at maturity, however, was seldom influenced by rotation treatment. The N treatment produced taller plants in most years.

Verticillium wilt was more prevalent in the continuous cotton than in the cotton following other crops. Wilt was also more prevalent on the N‐fertilized subplots.

Growing continuous cotton lowered the yields, hindered early season growth, and increased Verticillium wilt. Nitrogen fertilization reduced infiltration rate of water, which is an important consideration to farm managers in this area.
Effect of N Source, K Source, and K Rate on Soil Nutrient Levels and the Growth and Elemental Composition of Penncross Creeping Bentgrass, Agrostis palustris Huds.1
Authors: Waddington D. A. , Moberg E. L. , Duich J. M.
Published: July 2010

Relationships between soil nutrients, applied fertilizer, and turfgrass response are important in planning turfgrass fertilizer programs. A 4‐year study was conducted to determine the effects of five N sources (urea, Agrinite, Milorganite, Uramite, and Nitroform), two K sources (KCl and fritted potash), and three K rates (0, 1.2, and 2.4 kg/100 m2) on soil nutrient levels and the growth and elemental composition of Penncross creeping bentgrass (Agrostis palustris Huds.). Soil test levels, elemental content of clippings, and clipping weights were used to evaluate treatments.

Soil P and Mg levels were significantly higher with Milorganite as the N source. KCl applications increased K levels and decreased Mg and Ca slightly, whereas fritted potash increased both K and Ca. Tissue analyses indicated highest N with urea as the N source, lowest N with Agrinite, and highest P with Milorganite. Added K increased K in the clippings and decreased N, Ca, Mg, Mn, and Na. Although K additions decreased some elements in the soil and clippings, the magnitude of these changes was not considered critical under the conditions of these experiments. Significant yield differences due to N source decreased over the years. In general, clipping weights were not influenced consistently by K source or K rate; however, significant increases due to K have increased with time.
Electron Probe Analysis of Ca, Mg, and K in the Fruit of the Tomato, Lycopersicon esculentum, with Reference to Blossom‐end Rot
Authors: Murray Sylvia A. , Spurr Arthur R. , Paulson Kenneth N.
Published: July 2010

In order to increase our understanding of the incipient stages of blossom‐end rot in tomatoes (Lycopersicon esculentum), small pieces of pericarp tissue of immature fruits from the fruit apex, middle, and base were analyzed for Ca, K, and Mg. The vertical distribution of these elements and the relationships of the elements to each other were determined in healthy fruits and compared with those in blossom‐end rot fruits. In situ elemental analysis was done by an electron microprobe equipped with Ca, K, and Mg detectors for simultaneous analysis. There was virtually no difference in Ca, K, or Mg content between healthy and blossom‐end rot fruits, but there was a notable shift in the distribution of K between the healthy and blossom‐end rot fruits where K content increased in the fruit apex 10‐fold and decreased in the fruit base 2‐fold in blossom‐end rot fruits. This study has shown that blossom‐end rot is characterized by elemental relationships not apparent in healthy fruits, specifically the independence of K and Mg, and a significant (1% level) inverse relationship between Ca and Mg.
Influence of Mulches on the Growth and Development of Cotton Grown on Verticillium‐infested Soil1
Authors: Barrentine W. L. , Waddle B. A.
Published: July 2010

Soil surface mulches of asphalt, asphalt + white paint, cotton burs, and no‐mulch or check were compared in a field experiment involving cotton (Gossypium hirsutum L.) grown on verticillium wilt‐infested soil to determine if resulting changes in soil temperature could influence wilt incidence. Mean soil temperature, dry weight of seedling cotton plants, and seed cotton yield at first harvest were significantly reduced by the cotton bur mulch. The mulch from cotton burs, even though associated with a lowered soil temperature, however, was also associated with a lowered wilt incidence in the ‘Deltapine Smooth Leaf’ cultivar. The more wilt‐susceptible and earliermaturing cultivar, ‘Rex Smoothleaf,’ gave no mulch response as measured by wilt incidence. Covariance analyses indicated that the yield differences in seed cotton at first harvest were largely a function of differential seedling growth rates as measured by seedling dry weights.
Effects of Method of Harvest on Flue‐cured Tobacco. I. Agronomic Factors1
Authors: Brown G. W. , Terril T. R.
Published: July 2010

The optimum in mechanized harvesting of flue‐cured tobacco (Nicotiana tabacum L.) may involve the removal of all leaves in one operation. Field experiments were conducted during the 1968 and 1969 growing seasons to evaluate 12, 16, and 20 leaf topping heights and normal and once‐over harvesting methods for yield, value, and price of flue‐cured tobacco. A separate analysis was utilized to determine stalk position effects within the three topping heights. A significant year effect and its interactions, probably resulting from excess water received in 1968, were noted. The tobacco from the normal harvest method had a greater yield, value, and price than that harvested by the once‐over method, resulting from overmature bottom and immature top leaves, both of which cause lower dry matter yields and a lower price/45.2 kg. The high‐topped plants produced the greatest yield but the lowest price, reflecting greater amounts of lowervalued tobacco from the bottom and top leaves.

Yield was lowest at the lower stalk positions, increased to a maximum near the middle stalk positions, and then decreased at the upper stalk positions. Price was at a maximum at the lower‐middle stalk position and decreased in both directions. Leaves harvested by the once‐over method were lower in yield and price at the lower and upper stalk positions as compared to leaves harvested by the normal method. Disregarding the extreme lower and upper stalk positions, the once‐over harvest method resulted in leaves that were comparable to those harvested by the normal method.
Effects of Flooding and Gaseous Composition of the Root Environment on Growth of Corn1
Authors: Purvis A. C. , Williamson R. E.
Published: July 2010

The extent of root and shoot injury to corn, Zea mays L., plants exposed to various gaseous treatments (O2, CO2, N2) in the root environment and to flooding were determined from leaf area, stem diameter changes and root and shoot weights. The parameters of growth were measured before treatment, at the end of 1‐, 2‐, and 4‐day treatments, and after a 5‐day recovery period following treatment. The plants were grown in an environmental control chamber with roots of one group in an intermittent solution mist in airtight chambers and a second group in soil.

When treated for 1 or 2 days with 1.0% O2 with and without 20.0% CO2, the remainder being N2, only a slight reduction in growth was observed during treatment or recovery. However, treatment with this low level of O2 for 4 days caused a highly significant reduction in growth during treatment and recovery. Treatments with pure N2, 21% CO2 in N2, and flooding for 2 or more days reduced growth during treatment and recovery considerably more than did 1% O2 in N2. When these treatments lasted for 2 or more days, some of the lower leaves and a portion of the root system died. Flooding the soil caused somewhat less injury than did treatments with pure N2 or 21% CO~ in N2, possibly because some air was entrapped. Corn is severely injured if flooded or if the roots are in a zero O2 atmosphere for more than 1 day.
Effect of Artificial Defoliation on Sunflower Yields and Other Characteristics1
Authors: Johnson B. J.
Published: July 2010

Leaf removal studies were conducted on sunflowers (Helianthus annuus L.) from 1969 through 1971 at Experiment, Georgia, to evaluate the amount of leaf damage sunflower plants can tolerate without yield losses. Leaves from sunflower plants were artificially removed at levels ranging from none to all prior to flowering.

Sunflower seed yields were significantly reduced as a result of partial or complete leaf excision when compared with the undefoliated check. Yields were affected least when leaves 5 through 12 from the top or the top 12 were left on the sunflower plants. Lowest leaves on the plant were more important to seed yield than when only top 4 were left. The oil percent of seed was not affected by defoliation treatments when eight or more leaves remained on plants. Complete and partial leaf removal treatments reduced both seed weight and head diameter compared with the undefoliated check.
Relationships Between Furrow Opener, Corn Plant Spacing, and Yield1
Authors: Erbach D. C. , Wilkins D. E. , Lovely W. G.
Published: July 2010

In spite of proven yield advantages for corn (Zea mays L.) planted in narrow rows or at equidistant spacings, equipment expense and weed control disadvantages have slowed acceptance of these cultural practices. Improving plant spacing uniformity by decreasing the intra‐row spacing variance should be as effective in increasing yields as improving spacing uniformity by decreasing row width. To aid in determining what investment may economically be made to improve intra‐row plant spacing uniformity, the effect of such spacing on individual plant yield and total yield was investigated. Yields and plant‐spacing statistics also were obtained for corn planted with V‐type runner and double‐disk furrow openers. A relationship between individual plant yield and distances to adjacent plants was developed from plants harvested individually. This relationship, combined with a frequency function of distances to plants adjacent to the harvested plant, was used to compare yields of corn from conventional plant spacings with the yield of corn from a theoretical uniform intra‐row spacing.

The type of planter furrow openers investigated had little effect on yield or on intra‐row plant spacing uniformity. Intra‐row plant spacing accounted for only a small amount of the variance in individual plant yield. The study indicates that on a field scale, with corn planted in 76‐cm rows, improving intra‐row plant spacing may not significantly improve total yield. Therefore, it may not be economical to improve upon the intra‐row plant spacing uniformity obtained with conventional planters.
Total Nonstructural Carbohydrate Concentrations in the Herbage of Several Legumes and Grasses at First Flower1
Authors: Smith Dale
Published: July 2010

Herbage of several forage legumes and grasses was harvested at first flower (beginning of anthesis in grasses) and analyzed for percentage of total nonstructural carbohydrates (TNC) during 3 years. No significant difference was found among species for the 3‐year averages. However, red dover (Trifolium pratense L.), among the legumes, and timothy (Phleum pratense L.), among the grasses, were consistently high in TNC percentage during all 3 years.
Elemental Composition of Maize Grown Under No‐Till and Conventional Tillage1
Authors: Estes George O.
Published: July 2010

Grower acceptance of the no‐till technique for corn (Zea mays L.) production is increasing due to reduced labor costs, improved water and soil conservation by the herbicide‐killed cover crop, and frequently higher yields compared to conventional tillage. Information regarding macro‐ and micronutrient uptake by corn produced under the unique no‐till system is limited. This field study compares elemental composition, plant population, and yield of corn (var. ‘Wisconsin 335A’) under no‐till and conventional culture at five lime levels.

The concentration of Ca, Mg, Zn, Mo, B, and Al in corn leaf tissue was significantly reduced and K concentration was significantly increased under no‐till conditions. Significant soil pH increases were noted only under the no‐till system in the surface samples (O to 8 cm) at the two highest lime application rates (4 and 8 tons/ha). Plant population was reduced (16.1%), but silage yields increased (22.5%) with the no‐tillage method. This may reflect increased moisture conservation, since relatively dry growing conditions prevailed. The reduced nutrient utilization (with the exception of K) and plant population under no‐till conditions may justify changes in fertilization practice and an increase in seeding rates. The former is particularly important if no‐till methods were to be used over extended periods of time without plowing.
Yield and Percentages of Crude Protein and Green Herbage in Weeping Lovegrass Utilized for Deferred Grazing in Semiarid Argentina1
Authors: Vera R. R. , Menvielle E. E. , Templeton W. C.
Published: July 2010

Owing to the paucity of information on weeping lovegrass [Eragrostis curvula (Schrad.) Nees] accumulated for late fall and winter use a 2‐year field trial was conducted to ascertain the effects of N fertilization on yield and two quality indicators. Two levels of N, O, and 70 kg/ha, were used, with urea applied in February. A second experimental variable was time of harvest, with cuts spaced at monthly intervals beginning April 1 and ending Aug. 1. Nitrogen fertilization increased herbage crude protein percentage from 6.7 to 8.5 during winter and resulted in the production of 69% more forage. Relative proportions of green and dead herbage were not affected by N fertilization. Dry‐matter yields did not increase after April 1, 1970, but in 1971 maximum yields were not attained until the May harvest. Crude protein percentages were approximately 10 and 13 for the unfertilized and fertilized plots, respectively, at the April 1 harvests, but declined rapidly during April and May. It is concluded that during winter accumulated weeping lovegrass herbage from unfertilized fields is not likely to fill the nutrient requirements of grazing animals under climatic conditions prevailing in the area. Summer N fertilization and, in winter, alternative crops and feed supplementation are suggested as useful means of filling deficits at critical times.
Phytotoxicity of Herbicide Residues In Soils1
Authors: Fink Rodney J.
Published: July 2010

Injury to rotational crops by herbicide carryover has been experienced with some triazine herbicides. The objective of this study was to compare relative dissipation rates and carryover phytotoxicity of three triazine herbicides. Corn (Zea mays L.) was planted on May 2, 1969, May 2, 1970, and May 19, 1970. Two‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine (atrazine), 2‐chloro‐4‐(cyclopropylamino)‐6‐(isopropylamino)‐s‐triazine (cyprazine), 2‐(4‐chloro‐6‐ethylamino‐s‐triazine‐2‐ylamino)‐2‐methylpropionitrile (SD‐15418), and 2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl) acetanilide (alachlor) were applied on day of planting. Atrazine plus nonphytotoxic oil and cyprazine were applied postemergence 20 days after planting. Soil samples were collected 6, 12, 18, and 26 weeks after planting. Soybeans [Glycine max (L.) Merr.], alfalfa (Medicago sativa L.), and oats (Avena sativa L.), were planted in the soil and placed in a growth chamber. Dry matter yields of alfalfa, oats, and soybeans showed that alachlor had the least soil residual followed by SD‐15418, atrazine, and S‐6115. Merr. J, alfalfa (Medicago sativa L..
Nitrogen Fertilization and Clipping Effects on Green Needlegrass (Stipa viridula Trin.): III. Carbohydrate Reserves1
Authors: White Larry M. , Brown Jarvis H. , Cooper Clee S.
Published: July 2010

Nitrogen fertilization and frequent clipping have sometimes reduced cool‐season grass stands by reducing the carbohydrate reserves. We applied N and imposed clipping treatments to determine their effect on the seasonal variation of total nonstructural carbohydrates (TNC) in stem bases of dryland green needlegrass (Stipa viridula Trin.) during 1969. Ammonium nitrate was broadcast at O, 70, and 140 kg of N/ha in November 1968. Green needlegrass was either left undipped in 1969, or was clipped five times to a 5‐cm height at about 21‐day intervals from May through July.

Seasonal variation of TNC in stem bases of clipped and undipped plants was similar, but clipped plants had a lower percentage of TNC at all sampling dates. The TNC in nonfertilized, undipped plants decreased from 18 to 14% from growth initiation after winter dormancy (April 5) until after second leaf formation (April 28). The TNC increased after second leaf formation to 19% on May 20 just before boot stage, decreased slightly at inflorescence emergence (May 29), and then increased to 18% at first anthesis (June 9). Following first anthesis, TNC decreased to 9% on July 22 just prior to completion of seed dissemination, increased to 19% in late September, and decreased to 16% by November. The percentage of TNC in clipped plants was 3 to 5 units lower at all sampling dates, and the terminal value in November was 13%. Clipping in 1969 significantly reduced yields in 1970 and tended to reduce yields in 1971.

Nitrogen increased the percentage of TNC in the stem bases during mid‐July and again in late autumn, apparently as a result of new tiller development and increased photosynthesis. Nitrogen decreased the TNC only from growth initiation until the second leaf formation. Application of N in November 1968 increased yields in 1969, 1970, and 1971.
Some Effects of Field Weathering of Seed Cotton in a Desert Environment1
Authors: Buxton D. R. , Stapleton H. N. , Makki Yahia , Briggs R. E.
Published: July 2010

We conducted one greenhouse and two field experiments to measure some changes that occur to seed cotton (Gossypium hirsutum L.) properties when exposed to weathering in the desert environment of the southwestern U. S. In the field studies cotton was machine picked about every 10 days to investigate the effect of weathering. Each harvest was from cotton not previously harvested. Other plots were harvested repeatedly by hand to determine the contribution of late‐opened bolls to changes in seed cotton properties. In the greenhouse study open bolls were weathered for 10 weeks and sampled weekly. The bolls were moistened with 0.5 ml water per boll either weekly or twice weekly and compared with an unwatered check to investigate the effect of wetting and drying cycles that occur in the field from rain and dew formation.

Weathering did not result in loss of dry weight of lint or seed. Upper‐half‐mean‐fiber‐length was significantly reduced by the 10‐week greenhouse weathering period, but fiber fineness and strength were not affected. Weathering in the field resulted in average reductions of 0.8, 0.8, and 1.0% per week for upper‐half‐mean‐length, strength, and fineness, respectively, during October and November. These results show that harvesting late in the fall will not reduce yield if cotton does not drop to the ground, but a reduction in fiber quality can be expected.
Intensive Cultivation of Vanilla in Uganda1
Authors: Alconero R. , Stone E. G. , Cairns J. R.
Published: July 2010

Two field experiments were designed and implemented to determine the needs of vanilla (Vanilla planifolia Andrews) plants for shade, mulch, fertilizer, irrigation, and pesticides under intensive culture in Uganda. The area under experimentation in Uganda was found to be marginal in rainfall for the culture of vanilla. It is therefore necessary to irrigate during the dry periods of the year to avoid root rot, tip dieback, and loss of vines, as well as to have adequate growth of vines. A light canopy furnished by the support trees should filter about 50% of the sunlight. Mulch is best grown adjacent to the plantings. Neither pesticides nor fertilizers affected the factors measured significantly. Tip dieback can be avoided by maintaining the proper growing conditions of moisture, shade, and mulch.
Zinc Sources and Methods of Application for Rice1
Authors: Giordano P. M. , Mortvedt J. J.
Published: July 2010

Because of the relatively recent diagnosis of Zn deficiency in rice (Oryza sativa L.), the most effective sources of Zn and methods of application for flooded soils have not been established. In a greenhouse experiment, growth of rice on flooded Nolichucky sandy clay loam limed to pH 7.5 was similar with soil applications of ZnO, ZnSO4, and ZnEDTA. Uptake of Zn by immature plants was in the order: ZnO > ZnSO4 > ZnEDTA. Application of ZnSO4 to the flood water, the rice seed, or the soil resulted in comparable increases in dry matter production and Zn uptake.

The adherence of Zn to rice roots dipped in Zn suspensions and the subsequent availability to the plant was studied in the laboratory and the greenhouse. Suspensions containing ZnO were more effective in supplying Zn than those prepared with ZnS. The presence of attapulgite clay in the suspensions increased adherence to roots but decreased Zn availability to the plant. Suspensions containing more than 5% Zn were not practical because of excessive viscosity. Response, however, to Zn adhering to seedling dipped in suspensions containing 1 and 5% Zn as ZnO was similar to that where ZnO was mixed with the soil to supply 4 ppm of Zn.
Uptake and Distribution of Boron in Spanish Peanuts1
Authors: Chrudimsky W. W. , Morrill L. G.
Published: July 2010

The occurrence of boron deficiencies in Spanish peanuts (Arachis Hypogea L.) is Inconsistent in an environment as variable as that found in Oklahoma. A foliar analysis is needed to identify a boron deficiency potential in Spanish peanuts. The use of a foliar analysis requires a knowledge of the uptake and distribution pattern of the nutrient in question to assure proper sampling technique and correct interpretations. This study was conducted to determine the uptake and distribution patterns of boron in Spanish peanuts.

A greenhouse experiment with Eufaula loamy fine sand and three field experiments on Yahola loamy very fine sand, Norfolk loamy fine sand, and Durant loam were conducted to determine the distribution pattern of boron in the leaves and petioles of Spanish peanuts. Soil applications of O, 0.25, 0.50, and 1.00 ppm boron were applied to greenhouse pots containing 4,000 g of soil. Zero and 1.1 kg/ha of boron were applied to two field plots and O, 0.6, and 1.1 kg/ha of boron were applied to the third field plot. Leaflets and petioles were collected from varied parts of the peanut plant over a period of 70 days in the greenhouse and from July 16 through October 4 in the field.

The boron concentrations in the leaflets and petioles were significantly higher (5% level) from plants grown in the boron‐treated soil. The youngest petioles and leaflets reflected the most recent status of soil boron availability and were considered to be the desired foliar material for identifying boron deficiencies in Spanish peanuts by plant analysis.
Procedure for Adjusting the Yield of Plots of Burley Tobacco (Nicotiana tabacum L.) for Differential Stands1
Authors: Gupton C. L. , Archer L. E.
Published: July 2010

During 1968 and 1969 we conducted a study to determine whether the precision of yield estimates could be improved by adjusting plot yields for differences in stand of burley tobacco (Nicotiana tabacum L.). Plants were removed from the plots at four different stages of growth and in five different patterns. Both the stage and pattern of plant removal had significant effects on the plot yield of cured tobacco.

To derive an adjustment procedure for missing plants, we estimated the amount of compensation resulting from each stage and pattern of plant removal as the difference between the actual yield per plot and the expected yield, assuming no compensation. The proportion of the check plant average compensated for in a given pattern was computed as the ratio of the estimated amount of compensation to the average yield per check plant. A direct adjustment of plot yields to a full stand basis is possible after adding the equivalent number of plants resulting from compensation to the stand count.

The efficacy of our procedure was determined by applying it to data from a yield and quality trial that had a poor stand in 1971. Relative efficiencies were 100, 129, 139, and 149 for no adjustment and adjustment by Crew‘s procedure, covariance analysis, and our procedure, respectively.

To determine the nature of compensation by plants adjacent to missing plants, we computed standard partial regression coefficients, which were 0.2437 for plant height, 0.0180 for length of leaf, and 0.5972 for width of leaf. Plant height appears to exert a small influence on compensation, but the major influence is apparently the leaf width component of leaf size.
Opposite Alluminum and Manganese Tolerances of Two Wheat Varieties1
Authors: Foy C. D. , Fleming A. L. , Schwartz J. W.
Published: July 2010

Acid soil and solution culture studies showed that ‘Atlas 66’ wheat (Triticum aestivum L.) from North Carolina was more tolerant to excess Al but less tolerant to excess Mn than ‘Monon’ wheat from Indiana.

In greenhouse pots of Al‐toxic Bladen soil (pH 4.6 to 5.1) the top yields of Atlas 66 were significantly higher (5% level) than those of Monon; liming the soil to pH 5.8, however, equalized top yields of the two varieties. In Mn‐toxic Zanesville soil (pH 4.7 to 5.2) the varietal yield difference was just the reverse. At pH 5.2 the tops of Monon plants had fewer leaf symptoms (rolling and chlorotic spots) and yielded significantly more than those of Atlas 66; at pH 5.9 or 6.9, however, the two varieties were not significantly different in top yield.

In nutrient solutions containing between 4 and 32 ppm Mn at pH 4.6 the tops of Monon showed fewer leaf symptoms of Mn toxicity and yielded significantly more than those of Atlas 66, but with O or 2 ppm Mn added, the top yields of the two varieties were not significantly different. With Mn levels of 2 to 32 ppm, Monon root yields were significantly higher than those of Atlas 66, but with no Mn added the two root yields were not significantly different. At all Mn levels of 2 to 32 ppm in solution both tops and roots of Monon contained higher Mn concentrations than those of Atlas 66, but Monon plants showed less injury. For example, in Monon tops 2,561 ppm Mn was associated with a yield reduction of 12%. In Atlas 66 tops 1,250 ppm Mn (the highest concentration reached in Atlas 66) was accompanied by a yield reduction of 21%. In Monon roots 8,534 ppm Mn was associated with a root yield reduction of 20%, but 7,172 ppm Mn in Atlas 66 roots coincided with a 45% reduction in root yield.

Tolerance to one acid soil factor in a given plant genotype does not necessarily mean tolerance to another.
Effects of Spring Planting Date and Row Spacing on the Agronomic Characteristics and Chemical Composition of Crambe1
Authors: Massey John H. , Jellum M. D.
Published: July 2010

Crambe (Crambe abyssinica Hochst. ex R. E. Fries) has potential as a new oilseed crop. Since crambe is not winter hardy, an experiment was conducted at Experiment, Ga. to study the effects of spring planting dates and row spacing on agronomic characteristics and chemical composition of the seed. P.I. 247310 was spring seeded in 1969 and 1970 at four 1‐week intervals in three row spacings, 36, 53, and 71 cm. Seed yields were similar for all planting dates and averaged 724 kg/ha. Planting dates did not affect oil content or fatty acid composition of oil in 1969, but the earliest planting produced higher oil and erucic acid contents in 1970. Each 18‐cm decrease in row width produced approximately 30% more seed. Row spacing did not affect oil content or fatty acid composition. Planting date and row spacing did not significantly affect test‐weight, pod percentage, or plant height.
An Electric Scythe for Small Plot Harvest of Safflower1
Authors: Abel George H.
Published: July 2010

The blade of a scythe was replaced with an electric hedge trimmer to cut small plots of safflower (Carthamus tinctorius L.). Compared to the other methods, cutting time was decreased 25 to 75% and work was done with less discomfort.
A Major Cereals Project to Improve Maize, Sorghum and Millet Production in Africa1
Authors: Eberhart S. A. , Sprague G. F.
Published: July 2010

The objectives of this project, initiated in 1963, were 1) to increase cereal production in Africa through cooperation with and support of research organizations in Nigeria, Kenya, and Uganda, 2) to stimulate and sponsor cooperative research in all aspects of cereal production throughout the area, and 3) to provide in‐service training at the headquarters stations to individuals sponsored by their governments. This integrated program included plant breeders, entomologists, pathologists, and cereal technologists to develop new high‐yielding, disease and insect resistant varieties with increased food values, agronomists to develop a package of recommended cultural practices to exploit the potential of the new varieties, and research‐extension liaison officers to help extension personnel to reach the local farmers with the new varieties and recommended agronomic practices. Encouragement and assistance were given to cooperating agencies and companies for seed production, the development of marketing systems, and the utilization of the excess production. Kenya has been greatly increasing its maize production, and other African countries are moving forward.
Cotton Leaf Temperatures as Related to Soil Water Depletion and Meteorological Factors1
Authors: Ehrler William L.
Published: July 2010

In two field experiments with cotton (Gossypium), the relation between moderate soil water depletion and leafair temperature difference (ΔT) was investigated for feasibility of measurement and possible use as a guide to irrigation scheduling. Hourly temperatures of the upper leaves and of the air 1 m above the canopy were obtained for three cultivars of short‐staple cotton (G. hirsutum L.) and one of long‐staple (G. barbadense L.). In addition, hourly measurements were made of the vapor pressure 1 m above the crop. These data were taken during six irrigation cycles extending over two summers and encompassing a wide range of saturation deficit (SD).

In contrast to previous experiments in which a severe drought had been developed deliberately to intensity plant response, the experimental plots were irrigated on a schedule to obtain a high lint yield.

The temperature differences were measurable and predictable. When the SD remained steady from day to day, the mean daytime ΔT decreased 1 C on the day of irrigation and an additional degree the next day owing to leaf rehydration and consequent stomatal opening. Conversely, this 2 C decrease upon irrigation reflects the rise in ΔT that had occurred during the previous drying cycle. When the SD decreased appreciably, the stomatal opening caused by irrigation was masked. Because the SD seldom remains steady over long periods, a measurement of ΔT alone is not a sufficient indicator for irrigation. Thus, allowance was made for such changes in SD by calculating a regression of ΔT on the SD from data taken from a recently irrigated crop.

Although the use of ΔT to schedule irrigations seems feasible, the method is restricted primarily to regions with sunny climates. Even here it requires accurate, wellreplicated leaf temperature measurements as well as measurements of air temperature and vapor pressure.
Protein Content of Winter Wheat Grain as Related to Soil and Climatic Factors in the Semiarid Central Great Plains1
Authors: Smika D. E. , Greb B. W.
Published: July 2010

Protein content of wheat (Triticum aestivum L.) grain has decreased in recent years in the Central Great Plains. Conflicting reports concerning the causes for this decrease prompted this investigation. Protein content data from North Platte, Neb.; Akron, Colo.; and several southwestern Nebraska locations were shown to be negatively correlated by linear regression with total precipitation >1.25 cm for a 15‐day period 40 to 55 days before maturity (r = −0.70**) or with available soil water at seeding to a depth of 1.2 or 1.8 m (r = −0.79**). Grain protein levels were shown to be positively correlated by linear regression with total soil NO3‐N to depths of 1.2‐ or 1.8‐m (r = 0.82**) and by curvilinear regression with maximum air temperature for a 5‐day period 15 to 20 days before maturity (R = 0.74**). With all four factors combined, R2 = 0.96. With available soil water at seeding plus NO3‐N in the soil profile at seeding and protein content of wheat grain, R2 = 0.86. Maximum yield was obtained with 28 cm of soil water available at seeding, and at least 106 kg/ha of NO3‐N at seeding was needed to obtain grain with 12% protein.
Operational Value of Weather Information in Relation to Soil Management Characteristics1
Authors: Ewalt R. E. , Wiersma D. , Miller W. L.
Published: July 2010

Improved understanding is needed of factors that may govern the degree of usefulness of weather information to farm operators. This study was undertaken to evaluate the usefulness of precipitation forecasts and field conditions forecasts to farm operators in planning and conducting field operations. Possible relationships between farm operator valuations of forecasts, soil management characteristics, and the accuracy of precipitation forecasts were studied.

Two‐thirds of the 145 interviewed farm operators used both precipitation and field conditions forecasts in planning and conducting major field operations. These operators valued both types of forecasts at higher levels of usefulness than did the remaining one‐third, who used only precipitation forecasts. The usefulness of precipitation forecasts and field conditions forecasts increased with increasing water‐holding capacity and susceptibility of soils to physical problems such as cloddiness, tillage pans, and surface sealing.

Farm operators who used both types of forecasts valued them at approximately the same levels of usefulness in relation to major field operations conducted during the crop season. Highest values were associated with field operations that are conducted during the spring months. Precipitation forecasts were more useful than field conditions forecasts in making general management decisions. No relationship was found between the error rates of precipitation forecasts and farm operator evaluation of their usefulness.
Effect of Seed Maturation and Plant Population on Soybean Seed Quality1
Authors: Burris J. S.
Published: July 2010

Soybean (Glycine max (L.) Merr.) seed producers have shown a renewed interest in the premature defoliation of seed fields to facilitate earlier dry‐down and efficient harvest. This interest prompted this study on the effects of seed maturation (days after flowering) on seed quality. Four cultivars of soybeans were grown at 4 and 8 plants/ 30 cm rows in rows 75 cm apart. Individual flower nodes were identified at flowering. Pods were removed 30, 40, 50, and 60 days after flowering and allowed to air dry in the laboratory. The hand shelled seed was used to determine wt/100 seed, germination percentage, shoot and root dry matter, and cotyledonary weight remaining at the end of the seven‐day growth period. Seed size increased linearly with increased time after flowering. The low population produced significantly smaller seed than the high population. Germination percentages increased with increasing time after flowering, although the varieties Amsoy and Corsoy exhibited a reduction in germination between 30 and 40 days, primarily accounted for by an increase in the hard seed percentage. Shoot and root growth increased with increased time after flowering. Shoot growth was greatest and root growth was least in the high population.
Chemical Desiccation Experiments with Hard Red Spring Wheat, Triticum aestivum L.1
Authors: McNeal F. H. , Hodgson J. M. , McGuire C. F. , Berg M. A.
Published: July 2010

Chemical treatments were applied to ripening spring wheat (Triticum aestivum L.) cultivars over a two year period to determine if plant maturity and harvesting could be hastened. Bromoxynil, dalapon, NH4NO3, diquat, ametryne, and amitrole plus ametryne were applied as one or more spray treatment rates at weekly intervals, starting four weeks after heading. Agronomic and quality data from the chemical treatments were then compared to similar data from swathing and check treatments.

None of the chemical treatments reduced head moisture percentages significantly faster than that which occurred in the check. Also, diquat, ametryne, and swathing treatments at four weeks after heading significantly reduced test weight and grain yield.

Compared to the check plot, chemical treatments did not adversely affect milling and baking traits. Swathing, particularly that at four weeks after heading, reduced wheat protein, loat volume, and grain and texture by significant amounts. Increases occurred in grain protein percentages from ametryne treatments, but these increases were related to lower grain yields from these treatments.

It was concluded that these chemical treatments were ineffective as dessicants for spring wheat.