bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herbage Yield and Chemical Composition of Switchgrass as Affected by N, S, and K Fertilization1
Authors: Friedrich J. W. , Smith Dale , Schrader L. E. 
Published: July 2010

AbstractLittle information is available regarding the nutrient requirements of switchgrass (Panicum virgatum L.). The objective of this greenhouse study was to examine the effect of N, S, and K fertilization on the herbage yield, N/S ratio, and herbage concentrations of N and S in leaf blade, stem (culms and leaf sheaths), and total herbage fractions of switchgrass grown to anthesis. Three rates of N (0, 224, and 448 kg/ha of N as NH4NO3 in split application), three rates of K (0, 448, and 896 kg/ha of K as KHCO3), and two rates of S (0 and 56 kg/ha of S as CaSO4) were applied in all possible combinations (18 treatments) to pots containing soil cores of switchgrass.Dry matter yield of all herbage fractions increased significantly with each increment of N. However, for total herbage, stems, and inflorescences, yield increase with the second increment of N was dependent upon the application of S. K fertilization decreased inflorescence yield significantly at the highest rate, but did not affect dry matter yield of any other herbage fraction.At the highest rate of N, fertilization with S increased N concentration in the leaves, decreased N concentration in the stems, decreased the proportion of the total N localized in the stems, and increased the total herbage uptake of N. When S was applied, switchgrass responded to increased N fertilization by increasing S uptake. In contrast, when S was not applied, fertilization with N caused a dilution of tissue S and also decreased the proportion of the total herbage S localized in the stems. Concentration and content of N and S decreased with the first increment of K fertilization, but there was no change with the second increment of K. Critical N/S ratios for switchgrass appear to be greater than 10:1 for herbage, greater than 12:1 for leaf blades, and greater than 8:1 for stems.
Indirect Effects of a Thatch‐Inducing Herbicide On Soil Physical Properties Under Turf1
Authors: Jansen I. J. , Turgeon A. J. 
Published: July 2010

AbstractA measurable effect on soil physical properties was suspected where applications of calcium arsenate resulted in: 1) thatch formation in Kentucky bluegrass (Poa pratensis L.) turf, 2) restriction of rooting to the thatch layer, and 3) inhibition of earthworms in the underlying soil. The objective of this study was to determine the indirect effects of Ca3(AsO4)2 on the water infiltration capacity, hydraulic conductivity, moisture characteristics, bulk density and organic matter contents of surface soils from treated turfs.The soil studied was an Aquic Argiudoll and evaluation methods included: 1) the falling‐head, flooding method for measuring infiltration in the field, 2) the constant head procedure for measuring hydraulic conductivity in the laboratory, 3) a modified procedure utilizing Tempe cells for determining soil water retention characteristics, 4) the core method for measuring bulk density, and 5) a modified Walkley‐Black method for determining organic matter content. Infiltration rate and hydraulic conductivity were lower for the Ca3(AsO4)2 treated soils than for untreated soils. Treated soils had a higher bulk density, stored less water in the 0 to 1 bar tension range, and were lower in organic matter than the untreated soils. The marked alteration of soil physical properties observed to follow Ca3(AsO4)2 treatment is significant for turf management.
Influence of Variety and Soil Applications of Ca on Development of Ca Deficiency in Tobacco1
Authors: Peedin G. F. , McCants C. B. 
Published: July 2010

AbstractSome commercial varieties of the flue‐cured class of tobacco (Nicotiana tabacum L.) develop abnormalities of the buds and upper leaves which are typical of Ca deficiency. Utilizing varieties ‘Coker 254’ (susceptible) and ‘North Carolina 2326’ (slightly susceptible), a greenhouse experiment was conducted to study varietal differences in Ca accumulation and distribution, and six field experiments were conducted to determine the effect of source and level of soil Ca applications on degree of symptom development. In the greenhouse, seedlings were transplanted in sand and supplied for 31 days with solutions containing 1, 75, or 150 ppm Ca. In the field experiments, rates of 0, 28, 84, or 168 kg/ha Ca (as CaSO4) were band‐applied at transplanting; at one location and for two successive years, the variety and CaSO4 treatments were superimposed on rates of 0 and 1,121 kg/ha dolomitic limestone broadcast 2 months prior to transplanting. The soils used were classified as Typic and Aquic Paleudults and Typic Hapludults. In both the greenhouse and field, symptom expression of Ca deficiency was more pronounced on ‘C‐254’ than on ‘NC 2326’ plants, but reduction of symptom expression with increasing levels of Ca was obtained only in the greenhouse. Maximum dry weight for ‘C‐254’ was obtained with the 150 ppm Ca treatment, while the 75 ppm Ca treatment was sufficient for maximum growth of ‘NC 2326’. Conclusive evidence of varietal differences in Ca absorption was not obtained, but Ca concentrations in the apical tissues of ‘C‐254’ were substantially lower than those in apical tissues of ‘NC 2326’, indicating that absorbed Ca was distributed less effectively in ‘C‐254’ than that in ‘NC 2326’. Failure of ‘C‐254’ to maintain adequate Ca concentrations in apical tissues may be associated with its comparatively greater accumulation of dry weight and absorbed Ca in leaf than stalk tissue. In field experiments, Ca deficiency symptom development was not related to level of exchangeable soil Ca, and was not influenced by the rates of CaSO, and/or dolomitic limestone used. Rather, symptom development was less pronounced at locations where plants were subjected to prolonged periods of moisture stress during vegetative growth, indicating that Ca deficiency is more likely to develop on immature plants that undergo periods of rapid growth.
A Hand Caliper for Measuring Thickness of Soybean Pods1
Authors: McWilliams J. M. , Hatchett J. H. , Stadelbacher E. A. 
Published: July 2010

AbstractA precise, quantitative measure of pod growth, applicable from early pod elongation to full‐size green beans, was needed to determine the relationship of soybean [Glycine max (L.) Merr] pod maturity to insect seed feeding damage. Since pods increase in thickness as the seeds develop, measurements of pod thickness can be used for this purpose. A “V” type hand caliper that provided direct thickness measurements of pods in increments of 0.5 mm was devised. The change in pod thickness of a determinate soybean variety was determined by measurements taken in the field at different times during pod growth. The rate of increase in thickness was not uniform but averaged 0.5 mm/4 days. Characterization of pod growth by thickness has potential for relating pod development to insect damage and may have additional application for the study of other stress factors on yield.
Sulfur Requirements of Cowpea and Implications for Production in the Tropics1
Authors: Fox R. L. , Kang B. T. , Nangju D. 
Published: July 2010

AbstractLow S concentrations in rainwater and depleted organic matter reserves of soils are associated with S deficiencies in the seasonally dry West African savanna. The purpose of this study was to provide information on the internal and external S requirements of cowpea, a promising grain legume for tropical Africa. Three cultivars of cowpea [Vigna unguiculata (L.) Walp.] were grown in pots in which seven levels of SO4‐S were maintained in the soil solution. About 7 ppm S was required in the soil solution for 95% of maximum grain production for cultivars ‘TVu 76‐2E’ and ‘TVu 201‐ID’. Cultivar ‘Sitao Pole’ required about 2 ppm S in solution.The S contents of uppermost, fully expanded leaves at early flowering associated with 95% of maximum grain yield were 0.32% for Sitao Pole and 0.50% and 0.65% for cultivars, TVu 201‐ID and TVu 76‐2E respectively. The corresponding S content in the petioles was about 0.08%, 0.39%, and 0.42% respectively. Older leaves and leaf petioles accumulated S if it was supplied in excess of requirements.The S percentage of grain was 0.26% when yield was 95% of maximum. Sitao Pole accumulated S to a maximum of 0.36% when SO4‐S was supplied at 45 ppm in solution. About 30% of the plant S was in the grain of plants adequately supplied with S and about 50% was in the grain when the S supply was moderately deficient. The N/S ratio of upper trifoliate leaves associated with 95% of maximum grain yield was about 10 at first bloom.At near maximum yield, cultivar TVu 201‐ID contained about 80 mg S per plant in the grain. Assuming (65,000 plants/ha) the S requirement for grain was about five times mean annual S in the rainwater of northern Nigeria.Sulfur fertilization of field grown cowpea in southern Nigeria was accompanied by a small (12%) but statistically nonsignificant increase in yield. Sulfur fertilization (20 kg S/ha) was required to give 0.26% S in the grain.
Ratoon Cropping of Sorghum. III. Effect of Nitrogen and Cutting Height on Ratoon Performance1
Authors: Escalada Rodolfo G. , Plucknett Donald L. 
Published: July 2010

AbstractThe perennial habit of sorghum, Sorghum bicolor (L.) Moench, in a tropical climate permits the production of successive harvest of seed crops from an initial planting. Cultural treatments involving tillage and fertilization to favor such practice are termed ratooning. The objective of this study was to determine the effects of the various N rates and cutting heights on ratoon crops of sorghum at different seasons in relation to tillering behavior, yields, and other agronomic characteristics. Recognizing these effects would facilitate the timely application of the right amount of N fertilizer and proper cutting height to be done on ratoon crops.The performance of ratoon crops of grain sorghum, Sorghum bicolor (L.) Moench, ‘Pride 550 Br’, was studied as affected by four N rates (0, 100, 200, and 250 kg N/ha as urea) and three cutting heights (3, 8, and 13 cm) in the field in Hawaii. Performance characteristics studied were tillering behavior, yield and yield components, plant height, days to heading and maturity, and total plant N content. One half of the N was applied when the seedlings were about 3 weeks old; the other half side‐dressed at early booting stage.Generally, in the plant crop and ratoon crops, more tillers, larger leaf area, larger stalks, larger heads with more and heavier grains, and taller plants, and therefore, increased grain and stover yields were produced with higher N treatments up to 250 kg N/ha. Application of 100 kg N/ha increased the total plant N (percent) and further application of N (200 and 250 kg N/ha) increased the N concentrations in the plant from the first to the third ratoons. In the fourth ratoon and in Kilauea planting, total plant N did not increase despite N applications. Although yields increased as the amount of N increased, a leveling off or decline in yields at high N rates, occurred, indicating that optimum N rates were reached in this study. During winter, highest yields were produced with 200 or 250 kg N/ha and when plants were at the 13‐cm cutting height. In summer, higher yields were produced with the same N rates but lower cutting heights (3 and 8 cm).Based on this study, it is recommended that to obtain high grain and stover yields during winter and summer, 200 to 250 kg N/ha be applied to ratoon crops harvested at 13‐cm and 3‐ and 8‐cm cutting height, respectively.
Response of Dryland Cotton Plant Growth, Soil‐water Uptake, and Lint Yield to Two Extreme Types of Tillage1
Authors: Stibbe E. , Hadas A. 
Published: July 2010

AbstractBetter soil management prior to dryland cotton growing is not or hardly rewarded by a higher cotton lint yield production in a semi‐arid climate. More information about the soil moisture depletion pattern of dryland cotton on different tillage practices is needed. The purpose of this study was to evaluate the influence of differences in soil‐water stress in the root zone with time as a result of tillage practices on growth and yield of a dryland cotton crop. The soil‐water interaction patterns of roots of dryland cotton (Gossypium hirsutum L.) on two extreme types of tillage practices were studied in a field experiment with six replications per tillage treatment. The two tillage practices were plowing to a depth of 40 cm and a no‐tillage disking prior to the cotton growing season. Cotton was grown in a 2‐year rotation of dryland cotton and winter wheat (Triticum aestivum L.)Soil conditions created by the two tillage practices resulted in a denser and deeper root system of plants on plowed soil than on minimum‐tilled soil. Above‐ground vegetative growth of plants on plowed soil was more extensive and prolonged than of those on minimum‐tilled soil. Final lint yields of the crops on the two tillage treatments did not differ in the two seasons of study.Plants on plowed soil showed an increasing extraction rate resulting in a peak moisture stress in the reproductive stage. A relative‐constant rate was found for plants on minimum‐tilled soil in the period from emergence to early plowing and a moisture‐stress‐induced termination of the vegetative growth. It was indirectly inferred that differences in growing behavior and the similarity in lint yield of plants grown on plowed and minimum‐tilled soil were related to differences in magnitude and occurrence of soil moisture stresses developed in the root zone during the vegetative and reproductive stages of the cotton plant.
Prospects of Increasing Tropical Rice Production through Ratooning1
Authors: Bahar F. A. , De Datta S. K. 
Published: July 2010

AbstractProduction of a rice (Oryza sativa L.) crop by ratooning is feasible under some conditions. Ratooning of rice eliminates two labor‐saving operations: raising seedlings in the seedbed and transplanting in the main field.Field experiments were conducted for 2 years on Maahas clay (an isothermic clayey mixed Aquic Tropudalf) to evaluate the performance of rice cultivars for ratooning ability and the agronomic practices that affect ratooning. The agronomic practices studied were cutting height of the crop produced from seed (referred to as the “main” crop), N level, plant spacing, water management, and degree of land preparation.All the cultivars that were grown as ratoon crops were infected by the grassy stunt virus disease; the same cultivars grown simultaneously by transplanting and direct seeding were not infected. That indicates the high risks of growing virus‐susceptible cultivars as a ratoon crop.
Autumn‐Accumulated Tall Fescue and Orchardgrass. I. Growth and Quality as Influenced by Nitrogen and Soil Temperature1
Authors: Archer K. A. , Decker A. M. 
Published: July 2010

AbstractIn many situations autumn‐saved pastures offers an excellent alternative to more traditional and expensive livestock programs where hay or silage are the main winter feeds. Environmental conditions during the period of fall forage accumulation are markedly different from those of the spring and summer months and both forage yield and quality were affected. The objective of this research was to study the effects of temperature and nitrogen fertilization on the growth and quality of autumn‐accumulated forage. Two field experiments were conducted during 1970–71 on a Beltsville silt loam soil (Typic Fragiudults) to measure the influence of N rates and soil temperatures on the growth and quality of autumn‐saved ‘Ky‐31’ tall fescue (Festuca arundinacea Schreb.) and ‘Potomac’ orchardgrass (Dactylis glomerata L.). Nitrogen was applied at either 0, 50 (1970 only), or 100 kg N/ha in late September. In 1971 soil temperatures were maintained at ambient and approximately 12, 20, and 27 C during the autumn using specially designed field equipment. Forage samples were collected from randomly‐selected, previously unharvested areas. These were separated into green, dead, and miscellaneous fractions for yield and quality evaluation. Tall fescue was a more suitable species for autumn‐saved pasture primarily due to its superior growth compared with orchardgrass. Differences in quality were not consistently found between the species. In November of each year, dry matter availability reached a maximum of approximately 4,000 and 3,300 kg/ha for tall fescue and orchardgrass, respectively. During December under ambient conditions net loss of dry matter occurred in both species, presumably due to a greater rate of leaf death and decay than leaf growth. Digestibility and protein percentages decreased only slightly during autumn. The minimum IVDMD and crude protein levels measured during approximately 100 days of accumulation in either year were 80 and 13.5% for tall fescue and 73.0 and 15.2% for orchardgrass, respectively. Nitrogen fertilization stimulated growth of the autumn‐saved pastures and also tended to increase crude protein percentages. An application of 100 kg N/ha in late summer produced up to 50% more dry matter by early winter than zero N. IVDMD of the forage was not affected by N fertilization.Growth of the grasses during fall was stimulated by increasing the soil temperature. This effect was greater for tall fescue than orchardgrass. Plant quality was only slightly affected. However, the relative effects of the soil temperature treatments in relation to air temperatures and light parameters were not determined.
Nitrate Distribution and Variability in Irrigated Fields of Northeastern Colorado1
Authors: Ludwick A. E. , Soltanpour P. N. , Reuss J. O. 
Published: July 2010

AbstractFertilizer N recommendations in the Great Plains and Western USA are commonly based on soil NO3− tests, although NO3− content within soil profiles is subject to rapid change. The purpose of this study was to evaluate NO3− distribution within diverse soil profiles and determine NO3− changes occurring overwinter. Twenty‐six irrigated farm fields were systematically sampled in 1974 and 1975 by dividing them into 61 × 61 m grids (0.37 ha) and sampling to a 120‐cm depth by 30‐cm increments. Eleven fields were re‐sampled for fall vs. spring comparisons. Nitrate content tended to be greatest in the surface 30‐cm and decrease with depth; only three fields deviated markedly from the general pattern. Nitrate contents in the 0 to 30‐cm and 0 to 60‐cm depths were both highly correlated at the 0.01 level with that in 0 to 120 cm (r2 = 0.80 and 0.91, respectively), and actual NO3‐N content (0 to 120 cm) was within 30 kg/ha of the regression lines for 25 of 26 fields. All fields significantly increased in NO3,‐N from fall to the following spring, ranging from 8.1 to 68.9 kg/ha. Greatest increases occurred in the surface 30 cm. These increases were significantly related at the 0.05 level to decreases in NH4+ (r2 = 0.37), fall NO3− level (r2 = 0.43), and fall NO3− plus NH4+ level (r2 = 0.42), but not to organic matter or total N. There was a highly significant relation at the 0.01 level between fall ‐ and spring NO3− content of each sampled depth, ranging from r2 = 0.60 to 0.86. The above relationships should be useful in determining appropriate soil sampling depths for N fertilizer recommendations and developing calibrations based on sampling date.
Influence of Within‐row Variability in Plant Spacing on Corn Grain Yield1
Authors: Krall J. M. , Esechie H. A. , Raney R. J. , Clark S. , TenEyck G. , Lundquist M. , Humburg N. E. , Axthelm L. S. , Dayton A. D. , Vanderlip R. L. 
Published: July 2010

AbstractCorn (Zea mays L.) grain yields have been related to wide range of management practices. Row spacing and plant population effects have been well documented; however, little research has been conducted on the variability of within‐row plant spacing and its effect on grain yields.Experiments were conducted in 1972–75 at three irrigated locations in Kansas to determine the effect of within‐row variability of plant spacing on corn grain yields. Low variability was obtained by hand planting within machine planted areas which provided a range of variability. Within‐row variability of plant spacing was determined on 3‐m sections of rows by taking individual measurements between adjacent plants and calculating the standard deviation of spacing. Grain yields consistently decreased as variability of spacing increased at two of the three locations. The third location was more variable and in general showed no relationship between variability of spacing and grain yields. A survey of within‐row variability in plant spacing in fields in three Kansas counties indicated that planting precision could increase yields 200 to 1,200 kg/ha without changing planting rates.
Complementary Effect of Soil Puddling, Submergence, and Organic Matter on Rice Production1
Authors: Singh N. T. , Josan A. S. , Gupta J. P. 
Published: July 2010

AbstractPuddling of soil and submergence are common practices in lowland rice (Oryza sativa L.) cultivation. Researchers, however, disagree on the merits associated with one or the other practice. Both the operations involve additional labor and water and thus deserve critical evaluation of their role in rice production. A field study was conducted on Choa sandy loam (a Typic Ustochrept) to compare the individual and combined effect of preplanting puddling of soil vs. no puddling and post‐planting soil submergence vs. soil drained to field capacity. A,n additional treatment of organic matter at the rate of 5 metric tons/ha was included to increase biological reduction of the soil. All three practices significantly increased paddy yield. An average yield of 102.2 q/ha was obtained with continued soil submergence against that of 78.5 q/ha in plots where the soil water content was maintained between saturation and field capacity. The increase in paddy yield resulting from puddling and addition of organic matter was 15 q/ha and 8 q/ha, respectively. None of the practices seemed to be a substitute for the other. In fact, the combination gave a maximum paddy yield of 105.5 q/ha during 1972 and 121.5 q/ha during 1973. Maximum drop in soil Eh was observed with the addition of wheat straw followed by soil submergence and then puddling. The uptake of iron, zinc, and manganese by 45‐day‐old plants was neither related to soil Eb nor to the paddy yield. This study shows that both submergence and puddling are desirable practices in rice culture.