bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of Six Tropical Legumes Each in Combination with Three Tropical Grasses in Florida1
Authors: Kretschmer Albert E. , Brolmann J. B. , Snyder G. H. , Gascho G. J. 
Published: July 2010

AbstractSummer production of permanent grass pasture in southern Florida varies depending on the quantity of fertilizer N applied. Generally, commercial production is excessive even ,with minimum applications of N. Crude protein contents, however, are low because of rapid grass growth and concomitant dilution of the N. Because white clover (Trifolium repens L.) or other temperate legumes do not grow during the summer, an alternative possibility for increasing pasture quality is the inclusion of tropical legumes in permanent grass pastures.A small‐plot clipping experiment was designed to compare various tropical grass‐legume mixtures with grasses grown alone and receiving different rates of N fertilization. Comparisons were based on dry matter and crude protein yields and percentages.Each of the following legumes, Stylosanthes humilis HBK., Indigofera hirsuta Linn., ‘Hairy Indigo;’ Phaseolus atropurpureus DC., ‘Siratro;’ Desmodium intortum (Mill.) Urb., ‘Greenleaf;’ D. heterocarpen (Linn.) DC.; and Glycine wightii Willd., ‘Clarence,’ was grown in combination with Digitaria decumbens Stent., ‘Pangola’ digitgrass; Paspalum notatum Flugge., ‘Pensacola’ bahiagrass; and Setaria anceps Stapf., ‘Nandi.’Yields and N contents are reported for a 2‐year period. Setaria‐legume combinations generally were inferior to those of other grass‐legume mixtures. D. intortum‐grass mixtures produced 12,430 kg/ha of dry matter annually compared with 9,400 for Pangola and 5,740 for bahiagrass growing alone and fertilized with 126 kg/ha per year. Crude protein contents of harvested mixtures were higher than those for grasses alone that received N at the rate of 126 kg/ha.Crude protein yields of D. intortum‐Pangola mixtures were about three and a half times those for Pangola and five times those for bahia alone with the 126 kg/ha N rate. Average dry matter yield of the S. humilis‐grass mixtures was equal to those for average Siratro‐ and D. heterocarpon‐pon‐grass mixtures, but crude protein yield of S. humilis mixtures was less. Dry matter and crude protein yields of I. hirsuta and G. wightii mixtures were consistently less than those of other legume mixtures.
Implicit Estimate of Residual Nitrogen Under Fertilized Range Conditions in the Northern Great Plains1
Authors: Stauber M. S. , Burt Oscar R. 
Published: July 2010

AbstractInformation concerning carryover of fertilizer nitrogen in the plant‐soil system is necessary to determine optimum fertilizer policies for dryland grasses in semiarid regions. A primary contribution of this paper is the presentation and illustration of a dynamic model for estimation of carryover nitrogen. The carryover relationship is estimated implicitly through yield response as opposed to direct measurements on nitrogen. Data from an experiment designed to evaluate the effects of nitrogen and phosphorus fertilizers and seasonal precipitation on the yield and composition of bromegrass (Bromus inermis)‐crested wheatgrass (Agropyron cristatum) hay were analyzed with the model. A polynomial yield response equation in the two variables, plant‐available nitrogen and seasonal precipitation, was estimated simultaneously with a first order difference equation assumed to describe the residual nitrogen relationship.Statistical estimation was by nonlinear regression techniques. The proportion of nitrogen available in year t which was carried over to year t+1 was estimated at approximately 54%, taking precipitation at the mean of a 32‐year series, and the standard error associated with percent carryover was 3.4. A maximum yield of 2072 kg/ha (1849 lb/acre) resulting from 268.99 kg/ha (240 lb/acre) of available nitrogen is predicted under average precipitation conditions. The fact that an economic determination of the optimal level of nitrogen to maintain in the soil must include a consideration of carryover and the relevant interest rate is demonstrated. In equilibrium the optimal level of nitrogen is 89 kg/ha (79 lb/ acre), assuming an interest rate of 10%, a forage value of $.0165/kg ($15/ton), and a nitrogen fertilizer cost of $.22/kg ($.10/lb) with the costs of spreading fertilizer ignored. The maintenance of this level of nitrogen in the soil would increase average net returns over unfertilized grass by $2.27/ha or by about 20%.
Sorghum Growth and Nutrient Uptake in Relation to Soil Fertility, II. N, P, and K Uptake Pattern by Various Plant Parts1
Authors: Roy R. N. , Wright B. C. 
Published: July 2010

AbstractAn understanding of seasonal nutrient accumulation patterns under varying fertility levels is important for planning an efficient fertilization program. Field experiments were conducted to determine the effects of varying rates of N (0, 60, and 120 kg/ha) and P (0 and 26 kg/ha) on the N, P, and K accumulation pattern by various plant parts of a sorghum [Sorghum bicolor (L.) Moench] hybrid. Plant samples were collected at weekly intervals, partitioned into plant parts, and analyzed for N, P, and K.Nitrogen and P accumulation by whole plants increased almost linearly until maturity, but K accumulation was more rapid early in the season. A significant loss of K from the whole plant (and head) occurred during the last week. Nitrogen, P, and K accumulation rates were higher during the 35th to 42nd day and 70th to 91st day which coincided with the peak vegetative growth period and the grain‐filling stage, respectively. In unfertilized plants relatively higher translocation of N and P from the vegetative parts to the developing grain occurred. Little K was translocated. A much smaller percentage of total K was found in the head and more K accumulated in the stem than N and P.Application of 60 kg N/ha significantly increased N, P, and K yields of whole plant by 60.9, 49.4, and 19.1%, respectively. Further respective increases were 19.0, 18.9, and 12.3%, with 120 kg N/ha. Respective increases were 28.6, 49.0, and 17.1% with 26 kg P/ha over no phosphorus.
Beef Production on Bromegrass (Bromus inermis Leyss.) Pastures Fertilized with Anhydrous Ammonia1
Authors: Lechtenberg V. L. , Rhykerd C. L. , Mott G. O. , Huber D. A. 
Published: July 2010

AbstractSmooth bromegrass (Bromus inermis Leyss.) pastures were fertilized with anhydrous ammonia at 0, 112, 224, and 448 kg N/ha to determine the effectiveness of anhydrous ammonia as an N fertilizer on pastures and to determine the effect of high rates of N fertilization on seasonal trends in percent nitrate nitrogen (NO3‐N) and percent in vitro dry matter disappearance (IVDMD) of pasture herbage. A rotational grazing system was used with four tester animals per paddock. Additional animals were available, when needed, to graze the excess herbage.Anhydrous ammonia was as effective in increasing animal production per hectare as was ammonium nitrate at the same application rate. Nitrate‐N concentrations as high as 0.25% were obtained in early spring with the highest N application rates. No animal disorders were observed. Level of N fertilization had no effect on percent IVDMD. Both percent IVDMD and percent NO3‐N were high in early spring, declined during the initial portion of the grazing season, and then increased during the later part of the season. Nitrogen fertilization affected the seasonal trend in NO3‐N but not in percent IVDMD.
Yield Components and Quality of Siratro‐Kleingrass Association1
Authors: Siewerdt Lotar , Holt Ethan C. 
Published: July 2010

AbstractAn examination of the potential of a tropical legume to contribute improved forage production and quality as well as nitrogen (N) to a grass‐legume association was undertaken. ‘Siratro’ (Phaseolus atropurpureus D.C.) and ‘Kleingrass 75’ (Panicum coloratum L.) were chosen for study based on their reported performance. Siratro, introduced from Australia, was grown in association with Kleingrass 75, cut at different frequencies, and the contribution to dry matter (DM), crude protein (CP) content and in vitro digestible dry matter (IVDDM) was determined. Yield increased with less frequent cutting the first year, but no residual effects of cutting frequency were evident in the second year when all plots were cut uniformly. The mixture exceeded either the grass or the legume alone in yield. Siratro and Kleingrass 75 contributed equally to the association at the 3 and 5‐week cutting frequencies but Siratro made up 58% of the sward at the 7‐week frequency. Siratro was consistently high in CP whereas the grass alone and grass components declined with age. Siratro and Kleingrass were equal in % IVDDM at the youngest age, but the IVDDM of the legume remained constant with age whereas IVDDM declined with age in grass. Thus, the forage mixture was higher in crude protein and digestibility than the grass alone.
Effects of Clipping on Carbohydrate Reserves in Basin Wildrye1
Authors: Perry L. J. , Chapman S. R. 
Published: July 2010

AbstractBasin wildrye (Elymus cinerus Scribn. and Merr.) plants are difficult to maintain under spring grazing conditions. The objective of this study was to determine whether an association between carbohydrate reserve depletion and regrowth following clipping occurs in basin wildrye.After establishment, individual, spaced basin wildrye plants were clipped to 10 or 30 cm at three developmental stages in 1971. Total nonstructural carbohydrates (TNC) were measured on these plants 1, 2, 3, and 10 weeks following the initial clipping, and on additional plants, TNC was measured on regrowth of 3 weeks after each initial clipping. Seasonal TNC trends of undipped plants were also determined.Seasonal TNC levels of undipped plants declined rapidly during June. After this time, TNC levels increased through the summer, except for a decline in mid‐August associated with the following year's tiller development. Carbohydrate reserves (TNC) of plants clipped once or twice to 10 cm were significantly lower than for plants clipped to 30 cm at all three developmental stages at all dates. The greatest decline was associated with plants clipped twice to 10 cm. Within 3 weeks TNC was restored with plants clipped to 30 cm, but only slight restoration occurred with plants clipped to 10 cm. Ten weeks after the initial clipping, TNC levels of plants clipped to 10 cm were significantly lower than those of plants clipped to 30 cm.These results indicate that a severe depletion of carbohydrate reserves occurs following clipping. This may be associated with lack of resistance to spring grazing of basin wildrye.
Response of Soybeans Following Six Annual Applications of Various Levels of Boron, Copper, and Zinc1
Authors: Martens D. C. , Carter M. T. , Jones G. D. 
Published: July 2010

AbstractRelatively high levels of micronutrients are applied to some soils as fertilizers, fungicides, or waste products. Experimental data are needed to determine whether these micronutrient applications cause yield decreases or accumulations of micronutrients in edible plant portions. In this research, field investigations were conducted on Davidson clay loam and Marlboro fine sandy loam to determine tolerable levels of B, Cu, and Zn applications for soybeans [Glycine max (L.) Merr.]. Various levels of the micronutrients were applied to the two soils annually for 5 years preceding this investigation and for a sixth year prior to growing the soybeans under study. Neither soybean plant growth nor seed yield was decreased where as high as 3.3 kg B, 8.4 kg Cu, and 11.1 kg Zn/ha were applied to the soils annually for 6 years. This relatively high tolerance of soybeans to B, Cu, and Zn applications was attributed partly to a decreased untake of the micronutrients at the near‐neutral levels of pH in the soils. Evidence was presented indicating that the six annual applications of B, Cu, and Zn did not increase the concentrations of the micronutrients in soybean seed to levels that would preclude their use as animal feed.
Effects of Burning on Soil Temperature and Yield of Coastal Bermudagrass1
Authors: Monson Warren G. , Burton Glenn W. , Williams E. Jay , Butler James L. 
Published: July 2010

AbstractEarly spring burning of ‘Coastal’ bermudagrass (Cynodon dactylon (L.) Pers.) sod is a recommended practice for control of the 2‐lined spittlebug (Prosapia bicincta (Say) plant diseases, and winter weeds. This study was designed to determine effects of time of burning on dry matter yield, soil temperature, and forage quality. Coastal bermudagrass sod was burned at 2‐week intervals between mid‐February and late March for 6 years. When sod was burned about March 1, the average dry‐matter yield of Coastal bermudagrass was increased by 1,000 kg/ha over that of the unburned check plots. Digestibility and crude protein content of the grass were not affected by burning. Burning, regardless of date, resulted in increased soil temperature at 2.5, 5.0, and 10.0‐cm depths. Dry‐matter yields were related to soil temperatures, but the relationship appears to be subject to the modifying influences of rainfall, air temperature, and fertility. It is concluded that judicious burning of Coastal bermudagrass sod is a sound management practice with an added bonus of increased yield in most years. A portable shield for efficient burning of small plots is described.
Response of Several Rice Cultivars to Zn1
Authors: Giordano P. M. , Mortvedt J. J. 
Published: July 2010

AbstractDifferential response to Zn of several plant genotypes other than rice (Oryza sativa L.) has been shown by others. This study was conducted to compare the response to Zn of several foreign and domestic rice cultivars grown under varying fertility and water management conditions in greenhouse pot culture.Reduction in dry matter yields due to Zn deficiency in the several rice cultivars was in the order: ‘Bluebelle’ > ‘Bluebonnet‐50’ > ‘Dawn’ > ‘Nato’ > ‘Calrose.’ The very early maturing variety Bluebelle was less tolerant to low levels of available Zn than the later maturing cultivars, especially Calrose. Differences existed among cultivars with respect to Zn and P uptake, but could not be related to degree of Zn responsiveness. Adaptation to upland soil conditions differed among cultivars although both growth and Zn uptake were always higher under flooded conditions. The cultivar ‘Sinaloa’ from the Dominican Republic responded well to upland conditions whereas Calrose grew poorly. ‘Juma,’ ‘Bluebelle,’ ‘Starbonnet,’ and ‘Chontalpa’ were intermediate.
Effect of Inoculum Rate on Competitive Nodulation of Glycine max L. Merrill. I. Greenhouse Studies1
Authors: Weaver R. W. , Frederick L. R. 
Published: July 2010

AbstractTo study the competition between inoculated rhizobia and soil rhizobia in forming soybean (Glycine max L. Merr.) nodules, the effect of soil rhizobial population, inoculum strain, and inoculum rate on nodulation of soybeans was determined. Soybeans were grown under greenhouse conditions on 22 soils that contained populations of Rhizobium japonicum ranging from less than 2 to greater than I million/g of soil. Liquid inoculum containing up to 1 billion rhizobia was added to each 2.5 cm of planted row. After 6 weeks of growth, the soybean plants were harvested and the number of nodules, nodule fresh weight, and serotype of rhizobia forming the nodules were determined. Nodule numbers were not increased by inoculation when the soils contained more than 1,000 rhizobia/g of soil. With higher rates of inoculation, the proportion of nodules formed by the inoculum strain was greater. Multiple regression equations indicated that number of cells inoculated and number of soil rhizobia present accounted for 75% of the variation across soils in the percentage of nodules competitively formed by inoculum strains. Soybeans grown on soils containing 1,000 or more rhizobia/g are not likely to be extensively nodulated by inoculum rhizobia applied at normal rates (less than 10,000/seed).
Influence of Soil and Climatic Factors on Fertilizer Response of Wheat Grown on Stubble Land in Southwestern Saskatchewan1
Authors: Read D. W. L. , Warder F. G. 
Published: July 2010

AbstractIn southwestern Saskatchewan moisture and nutrients are frequently limited for wheat (Triticum aestivum L.) grown on stubble land which had produced a crop the previous year. Variations in the severity of limitations between years resulted in wide variations in yield, quality, and response obtained from fertilizer application. Field fertilizer tests were conducted for 4 years to determine the effect of measurable soil and climatic factors on the response of wheat on stubble land to applied N and P fertilizer.A stepwise multiple regression computer program was used to measure the effect of independent variables on dependent variables when different rates of N and P fertilizers were used. The independent variables were soil moisture and nutrient content at seeding, rainfall during the growing season, and rainfall deficits for half‐month periods during the growing season. The dependent variables were yield, protein and P content of the grain, and net returns.Each of the independent variables assumed a different degree of importance when compared with different dependent variables. However, certain generalizations are possible.The NH4‐N form of soil N was responsible for more of the variations than the NO3‐N form. Rainfall during the growing season had a greater influence than stored soil moisture on the yield and protein content of grain grown on unfertilized plots, but the amount of stored soil moisture had greater influence on the effect of fertilizer on the variation in yield and protein content than did summer rainfall. Climatic factors during the growing season were important in causing yearly variations in the unfertilized plots, but the factors that could be measured before seeding had a greater influence on the response to fertilizer.A knowledge of these variables and of the effect that they have on variations in the response to fertilizer is necessary when planning a fertilizer program.
Triazine Susceptibility of Fall Panicum and Small Crabgrass1
Authors: Harvey R. G. , Doersch R. E. 
Published: July 2010

AbstractFall panicum (Panicum dichotomiflorum Michx.) and small crabgrass [Digitaria ischaemum (Schreb.) Muhl.] are becoming increasingly important problems for corn (Zea mays L.) production because of their apparent tolerance to atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine]. It is important to consider other herbicides for the control of these problem weeds and essential to maintain the control of weeds sensitive to atrazine. Consequently, it seems necessary to determine the value of other triazine herbicides for the control of these problem grasses. Experiments were initiated to assess the relative effectiveness of atrazine, cyanazine {2‐[(4‐chloro‐6‐[ethylamino]‐s‐triazine‐2‐methylpropionitrile}, cyprazine [2‐chloro ‐4‐ (cydopropylamino)‐6‐(isopropylamino)‐s‐triazine] and simazine [2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine] for control of fall panicum and small crabgrass in corn when applied alone and in combination. Before greenhouse trials could begin, procedures for breaking dormancy of weed seeds were needed. Germination studies demonstrated that fall panicum seed required prechilling and small crabgrass seed required H2SO4 scarification in order to germinate under laboratory conditions. Greenhouse studies indicated that the order of effectiveness of the herbicides on fall pauicum was cyanazine = simazine> cyprazine>atrazine, and on small crabgrass was cyanazine>simazine>cyprazine>atrazine. Fall panicum was more susceptible to atrazine, cyprazine, and simazine than was small crabgrass, but small crabgrass was more susceptible to cyanazine. Depth of herbicide placement in the soil greatly affected the weed control obtained under greenhouse conditions, suggesting that leaching of the herbicides under field conditions may reduce their effectiveness. Field studies conducted in 1971 and 1972 at two locations tended to verify the greenhouse observations.
Growth of Kikuyugrass (Pennisetum clandestinum) Under Clipping. I. Effects of Nitrogen Fertilization, Cutting Interval, and Season on Yields and Forage Characteristics1
Authors: Whitney A. S. 
Published: July 2010

AbstractKikuyugrass (Pennisetum clandestinum Hochst. ex Chiov.) is an important pasture forage, soil cover, and weed in many parts of the subtropics. Responses to N have been reported, but the relationships among management, climate, and forage production have not been well defined. We therefore studied the regrowth of kikuyugrass under 3 N levels (22, 56, and 168 kg/ha per year), and 3 cutting intervals (2, 5, and 10 weeks) for 3 years at 2 locations (Kula and Makawao, Maui). The Kula site was at 945‐m elevation on an Eutrandept, and the Makawao site was at 660‐m elevation on a Tropohumult. Average yields ranged from 4.8 to 29.4 metric tons/ha per year at Kula and from 10.2 to 32.5 metric tons/ha per year at Makawao. Average percent N in the forage was little affected by N rate except for an increase at the highest N rate at Makawao.Cutting at 2‐week intervals reduced yields per unit time to 20 to 50% of the 10‐week yields at Kula and to less than 15% of the 10‐week yields at Makawao. Over a 3‐year period, yields of 5‐week regrowth (per unit time) were 32% of the 10‐week yields at Kula but 65% of 10‐week yields at Makawao. Crude protein levels in the forage under frequent cutting averaged 1.5 to 2.0 times that in 10‐week regrowth. Two‐week regrowth was also higher in acid‐detergent solubles and lower in fiber and cellulose than 10‐week regrowth. Ten‐week regrowth from the high N treatment was higher in fiber and lignin than similar forage from the low or moderate N levels, indicating the need for careful management of N‐fertilized kikuyugrass.Dry matter yields of 5‐week regrowth fluctuated more with season than 10‐week regrowth yields, ranging from 1.4 to over 100 kg/ha per day. Five‐week regrowth yields were reduced by 11 kg/ha per day for each degree of decrease in average minimum soil temperature below 18 C (r2 = .93). Above 18 C, yields increased about 16 kg/ha per day for each 100 ly/day increase in average solar radiation (r2 = .64). Percent crude protein in the forage was inversely related to air or soil temperature and day length (multiple R2 =.57).Residual effects of N fertilization were greater on the Tropohumult than on the Eutrandept. After 3 years of clipping, cations were severely depleted from the upper horizons of both soils.