bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Dynamic Model for Technical and Economic Analysis of Fertilizer Recommendations1
Authors: Lanzer Edgar A. , Paris Quirino , Williams William A. 
Published: July 2010

AbstractThe rationale of this study was to jointly estimate response functions for N, P, and K for wheat and soybean cropping in southern Brazil and carryover functions for residual fertility. The two sets of functions were then combined in a dynamic model having general applicability for optimizing fertilizer recommendations. The model is composed of (a) a yield‐nutrient response function incorporating Liebig's Law of the Minimum and Mitscherlich's relative yield theory, (b) fertility carryover functions for P and K, and (c) a multiperiod economic programming model which combines crop yield response and carryover functions with crop and fertilizer prices. Important implications are that (a) the Law of the Minimum assume no nutrient substitution, (b) the relative yield theory allows pooling response data from different experiments, and (c) the fertilization problem is treated as a dynamic process that utilizes revised measures of soil fertility as they become available through soil tests. The crop response was specified as a piecewise linear and plateau function while the fertility carryover was postulated as a first order difference equation, incorporating an exponentially declining process of soil fertility. The solution of the overall dynamic model took the form of a multiperiod linear programming problem.The N, P, and K response functions for wheat (Triticum aestivum L.) and soybean (Glycine max L.) yields were generated from 38 fertilizer field experiments conducted at Rio Grande do sul and Santa Catarina states in southern Brazil between 1968 and 1976. The seven experiments that were repeated for 4 years provided the information for estimating the carryover effects of P and K fertilization.The results indicate that the optimal target levels of soil fertility are in accordance with those recommended locally. The maintenance applications recommended, however, are substantially different than the optimal quantities determined by the dynamic model presented here. The model calls for a reduction of the current maintenance application for both N and P of 10 kg/ha and an increase for K of 12 kg/ha. This would result in a U.S. dollars saving of $27/ha 1 year.
Effects of Cattle Feces Rapidly Buried by Dung Beetles on Yield and Quality of Coastal Bermudagrass1
Authors: Fincher G. T. , Monson W. G. , Burton G. W. 
Published: July 2010

AbstractCattle numbers have steadily increased in the southeastern United States partly in response to increased fertilizer use and higher producing forage varieties that permit higher stocking rates. Heavily stocked pastures result in accumulation of feces on pasture surfaces and contamination of forage. This study was initiated to study the effects of rapid burial of cattle feces by dung beetles on Coastal bermudagrass [Cynodon dactylon (L.) Pers]. Fresh cattle feces containing the equivalent of 224 kg N/ha were applied to duplicate plots of Coastal bermudagrass for determinations of pasture yield: 1) when feces are buried by dung beetles, and 2) when feces remain on the pasture surface. The soil was a Tifton loamy sand (Plinthic Palendults; fine‐loamy, siliceous, thermic family) . Dung beetles confined to one‐half of the plots buried 78% (175 kg N/ha) of the applied feces. Total dry matter yields were 7,791 kg/ha where the feces were buried by beetles and 6,364 kg/ha where not buried as compared to yields of 5,369 and 8,305 kg/ha where 112 and 224 kg N/ha were applied as ammonium nitrate. The yield from plots with the buried feces was not significantly different from that from plots receiving 224 kg/ha of N fertilizer. Similar results were obtained when wheat was oversecded on Coastal bermudagrass plots in which the effect of application of ammonium nitrate fertilizer was compared with that of cattle feces buried by dung beetles in the fall. Burial of feces by a greater than normal dung beetle population on pasture with grazing cattle also produced higher yields of Coastal bermudagrass compared to similar pastures with lower dung beetle populations. The results indicated that Increasing the dung beetle population on pastures by introduction of foreign species of beetles would be very beneficial for forage production in high density grazing systems.
Dry Matter Production and Nitrogen Utilization by Six Potato Cultivars1
Authors: Kleinkopf G. E. , Westermann D. T. , Dwelle R. B. 
Published: July 2010

AbstractThe rate and duration of tuber growth largely determines the final potato (Solanum tuberosum L.) tuber yields. Cultivars that continue leaf development and nutrient uptake while maintaining maximum tuber growth rates may have higher final tuber yields, yet different N requirements. The objective of this study was to obtain information relating plant growth rates to N availability for selected potato cultivars. Total dry matter accumulation and N assimilation patterns of indeterminant cultivars, ‘Russet Burbank’, ‘Lemhi Russet’, ‘Centennial Russet’, and one advanced selection A66107‐51, were compared with that of two determinant cultivars, ‘Pioneer’ and ‘Norgold Russet’, at three N levels. Cultivars were grown in a field experiment on a Portneuf silt‐loam soil (Xerollic Calciorthids).High available soil N levels at planting delayed the linear potato tuber growth period 7 to 10 days but had minor effects on the time of tuber initiation for the indeterminant varieties. Maximum tuber growth rates (tuber bulking) were 900 to 1,300 kg/ha/day. A66107‐51 was superior in N‐use efficiency to the other cultivars. Between 70 and 100% of the total available N was utilized by this cultivar in producing high yields. This information may be used to select lines and cultvars that will optimize production. A knowledge of plant growth and N uptake rates can improve the fertilizer recommendations for each cultivar.
Nitrogen Fixation Rates of Alfalfa and Red Clover Grown in Mixture with Grasses1
Authors: Craig Lelia de Anda , Wiebold W. J. , McIntosh M. S. 
Published: July 2010

AbstractNitrogen contributions of legumes to grass‐legume mixtures are estimated on the basis of legume monocultures and may need to be adjusted to reflect any effect of the companion grass. An experiment at two field locations was conducted to determine whether the N2‐fixation rates of alfalfa (Medicago sativa L.) and red clover (trifolium pratense L.) were significantly affected by mixed culture with orchardgrass (Dactylis glomerata L.) or timothy (Phleum pratense L.). Legumes and grasses were grown in eight mono‐ or mixed cultures. Specific nodule activity (SNA) was estimated by acetylene reduction at first flower of legumes and 4 weeks after initial harvest. Grasses were analyzed for total N (TN). Legume dry weight per plant was reduced by association with grasses in only one determination at one location. Grass TN 4 weeks after initial harvest was in most instances increased significantly by the legume. Specific nodule activities of red clover grown alone and red clover grown with grasses were similar and did not change between determinations. The SNA of alfalfa grown with grass was significantly higher than that of alfalfa grown alone for the second determination at one location. The SNA of alfalfa in mixed culture increased between determinations; however, SNA of alfalfa monocultures did not change. It is concluded that grass plants are not detrimental to legume plants and may stimulate N2‐fixation. Some transfer of N from legumes to grasses may occur when the two species are grown in mixed cultures.
Use of Saline Water for Supplemental Irrigation of Sugarcane1
Authors: Thomas J. R. , Salinas F. G. , Oerther G. F. 
Published: July 2010

AbstractSupplemental irrigations of sugarcane with saline ground waters may become necessary in the Lower Rio Grande Valley of Texas, since the water requirement of this crop greatly exceeds the irrigation water allotment. Experimental objectives were to determine the feasibility of using saline ground water for supplemental irrigation of sugarcane and to compare the effects of water quality on cane and sugar yields, juice quality, and the mineral composition of leaves and juice. Sugarcane cv. ‘N.Co. 310’ growing on Hidalgo sandy clay loam (Typic Calciustolls) was irrigated with river (EC = 1.4 mmho/cm) and a prepared saline water (EC = 4mmho/cm) under five irrigation treatments. Yields of cane (r = −0.85, significant at the 0.05 level of probability), seasonal mean stalk elongation rate (r = −0.95, significant at the 0.01 level of probability), stalk length at harvest (r = −0.94, significant at the 0.01 level of probability) and electrical conductivity (ECj) of the juice (r = −0.93) were linearly correlated with the weighed mean salinity (ECw) of the irrigation waters in 1974, a relatively dry year. Juice Cl concentrations were linearly correlated (r = 0.94, significant at the 0.01 level of probability) with the CI concentrations of the irrigation waters. Because of the leaching effect of rainfall, the effects of saline water irrigations on soil salinification and plant growth were minimized. Root zone salinity (ECe) levels were less than the threshold salinity level of 5.9 mmho/cm. Consequently, the effects of water quality on yields were small and generally nonsignificant.The average annual rainfall (67.9 to 43.9 cm) across the Lower Rio Grande Valley is probably sufficient to lower salinity if saline well waters were used for supplemental irrigation on medium texture soils. In 1974, 42.3 cm of rain after the final irrigation decreased the ECsw values at the 46 cm depth to less than 1 mmho/cm. This suggests that waters with salinity concentrations above 4 mmho/cm could probably be used to irrigate sugarcane of medium texture soils in the Lower Rio Grande Valley of Texas.
Alfalfa Management Under Saline Conditions with Zero Leaching1
Authors: Francois L. E. 
Published: July 2010

AbstractPrevious studies have shown that alfalfa (Medicago sativa L.) can tolerate high salinity levels in the lower portion of the root zone without significant yield reduction, provided the upper portion of the root zone is maintained relatively free of salinity. The question of how much salt can be stored in the lower root zone before encroachment into the upper root zone occurs with subsequent yield reduction remains unanswered. Consequently, a study was conducted in greenhouse lysimeters to determine salt storage capacity in the lower part of the root‐zone and the long‐term effects of this management on plant growth. The lysimeter soil was Pachappa fine sandy loam (mixed, thermic, Mollic Haploxeralf).Alfalfa was grown with and without leaching using an irrigation water having an electrical conductivity of 1.0 dS/m in soil profiles 0.6, 1.2, and 1.8‐m deep for 9, 14, and 20 months, respectively. During these respective time periods yield from the nonleached lysimeters was reduced less than 25% while more than 14.6, 30.2, and 45.6 Mg/ha of salt was stored in the bottom half of the three soil profiles. The deeper the soil the greater the capacity to store salt with minimal yield reduction. Yield was drastically reduced once salt build‐up began in the upper portion of the root zone. Consequently, irrigating to leach accumulated salt out of the upper root zone may be necessary but this can be accomplished during the winter or off season when water is more readily available. Shallower soil profiles may require more frequent leaching.
Production and Competition of Crested Wheatgrass‐Native Grass Mixtures1
Authors: Schuman G. E. , Rauzi F. , Booth D. T. 
Published: July 2010

AbstractMining in the Northern Great Plains is resulting in the disturbance of large acreages of rangeland which requires revegetation to stabilize the soil resource and return it to productivity. The competition of ‘Nordan’ crested wheatgrass [Agropyron desertorum (Fisch.) Schult.] with four individual native grass species and with a mixture of the four species was evaluated in the field at Cheyenne, Wyoming. This study was initiated to determine if crested wheatgrass, an easily established introduced species, can be seeded with more difficult to establish native grasses and result in a diverse community. Crested wheatgrass was seeded with slender wheatgrass [A. trachycaulum (Link) Malte], thickspike wheatgrass [A. dasystachyum (Hook.) Scribn.], western wheatgrass (A. smithii Rybd.), and green needlegrass (Stipa viridula Trin.) or with a mixture of these four native species in the fall of 1976 on an Archerson fine, sandy, clay loam (Aridic Arguistol). Crested wheatgrass comprised 25% of the seed mixture in all treatments. In 1977, 69.5, 42.5, 22.5, and 22.6% of the total production was slender, thickspike, and western wheatgrass and green needlegrass, respectively. In 1980, production of slender, thickspike, and western wheatgrass and green needlegrass was 2.6, 15.5, 15.5 and 36% of the seeded species production, respectively. This decrease in percentage of production of the native wheatgrass species was the result of a large increase in crested wheatgrass production.When crested wheatgrass was seeded with the mixture of all four native species, the 1977, 1978, 1979, and 1980 production of the native species represented 62.4, 31.2, 21.3, and 4.3% of the seeded species production, respectively. The major decline in percentage of production contributed by the native species in 1978 was largely due to the loss of slender wheatgrass. In 1977, slender wheatgrass represented 76.8% of the production of the native species, however, it declined to 18.2% in 1978. By 1980, all of the native species had declined to the point that the mixture was nearly a pure stand of crested wheatgrass.It appears that green needlegrass when seeded alone with crested wheatgrass is able to successfully compete and make substantial growth. However, inclusion of other native species in the mixture with green needlegrass resulted in a greater competition among the native species, which caused a decline in green needlegrass production. Seeding crested wheatgrass with these native species or with a mixture of these native species is not recommended if you desire a major portion of the production to be native species. Although crested wheatgrass represented 25% of the seed mixture in all treatments, after 4 years it represented at least 64% of the production.
Sodium Hypobromite Oxidation Method for Determination of Total Phosphorus in Plant Materials1
Authors: Dick W. A. , Tabatabai M. A. 
Published: July 2010

AbstractA simple, sensitive, precise, and rapid method for determination of total P in plant materials is described. The sample is heated with alkaline sodium hypobromite solution to oxidize the P compounds to phosphate, and the phosphate thus obtained is extracted with 1N H2SO4 and determined colorimetrically by a heteropoly blue color method. Comparison of results obtained by the hypobromite oxidation and HNO3‐HCIO4 digestion procedures showed that the average total P values by the two methods for 20 plant samples and animal manures analyzed were 0.385 and 0.384%, respectively. In addition to being safe, digestion of plant samples with sodium hypobromite solution and colorimetric determination of the extracted P by the method of Murphy and Riley permits 100 analyses to be performed by a single operator in a normal working day.
Takadiastase Enzyme Pretreatment for Determining Cell Wall Constituents in Corn and Sorghum Silages1
Authors: Smith D. H. , Marten G. C. , Britton R. A. 
Published: July 2010

AbstractThe conventional Van Soest (VS) method of determining cell wall constituents (CWC) of forages often results in artificially high CWC yields with high‐grain cereal silages due to starch contamination. Our objective was to determine, the feasibility of use of a takadiastase enzyme pretreatment (TEP) to remove starch before neutral detergent extraction in CWC determination. In preliminary studies with a highgrain corn (Zea mays L.) silage, CWC residues from the VS method and from the TEP method contained 16.2 and 1.7% starch, respectively. Subsequent studies were conducted using 13 corn and 13 sorghum [Sorghum bicolor (L.) Moench] silages to compare the reliability of CWC values obtained from VS, TEP, and a procedure suggested by Fonnesbeck and Harris (FH) that utilizes acid and pepsin pretreatments before neutral detergent extraction. The mean CWC values obtained by using TEP were lower for both types of silages than were those from VS and FH methods. Correlation coefficients between in vivo digestible dry matter (sheep) and CWC values for corn and sorghum silages were, respectively, 0.63 (P < 0.05) and −0.44 (P < 0.12) for the VS method, −0.29 (P < 0.33) and −0.81 (P < 0.01) for the FH procedure, and −0.54 (P < 0.06) and −0.80 (P < 0.01) for the TEP modification. Use of a 24‐hour TEP prior to normal extraction in neutral detergent produced more easily filtered CWC residues for high‐grain silages than did the VS procedure, and the TEP residues were closer to being starch‐free. The CWC values from TEP and FH procedures were significantly (P < 0.01) correlated (r = 0.77 and 0.90 for corn and sorghum slages, respectively) while those from the TEP and VS procedures were not significantly correlated.We conclude that the 24‐hour TEP method is superior to the FH procedure for overcoming the filtering and excess starch problems inherent in the VS procedure for CWC analysis of high‐grain silages. In particular, TEP is simpler than FH and it does not extract cell wall proteins that could be removed by the acid‐pepsin phase of the FH procedure.
Infrared Thermometry for Scheduling Irrigation of Corn1
Authors: Clawson Kirk L. , Blad Blaine L. 
Published: July 2010

AbstractIrrigation scheduling is an increasingly important practice in the management of valuable water resources in agricultural regions. The study reported here was conducted to evaluate the feasibility of scheduling irrigation in corn (Zea mays L.) using canopy temperature data obtained with a hand‐held infrared thermometer (IRT).Specific objectives of the study were: 1) to determine whether irrigations can be scheduled from crop canopy temperature data and 2) to evaluate the effectiveness of various canopy temperature irrigation scheduling methods through their effects on some plant responses and the soil water balance.The study was conducted at the Sandhills Agricultural Laboratory located near Tryon, Neb. The soil at the site is classified as a Typic Ustipsamment (Valentine fine sand). The range in temperature of six readings made with an IRT—defined as the canopy temperature variability (CTV)—in a fully irrigated reference plot (WW) was less than 0.7 C. As the temperature difference between a water‐stressed plot and the WW plot increased so did CTV values until a critical stress level was reached beyond which CTV values stabilized. The onset of water stress can, therefore, be signaled when CTV values exceed 0.7 C.Observations of CTV were the basis for one type of irrigation scheduling procedure. Irrigation was initiated when the range of six measurments in a plot exceeded 0.7 C. A second procedure consisted of comparing the difference between the average canopy temperature of the well‐watered plot (WW) with that of the plot to be scheduled. Irrigations were initiated when plot temperatures became either 1.0 (1SMW; SWM = Stressed Minus Well‐watered) or 3.0 C (3SMW) warmer than the well‐watered plot.A total of 283 mm of irrigation water was applied to the WW plot whereas the CTV plot received 127 mm. By the end of the growing season almost all available water had been extracted from the soil in the temperature scheduled plots but the soil profile remained near field capacity in the WW plot. This suggests that during the growing season soil water was most effectively used in the temperature scheduled plots.Grain yields (Y) were reduced in the order of increasing water stress as follows: YWW > YCTV > Y1SMW > Y3SMW > YDL YDL is the yield from a dryland (DL) plot which received no supplemental irrigation. Yields of grain in the CTV treatment were slightly lower than in the WW plot, but not significantly so. This suggests that plants in the CTV plot received adequate water. Grain yields in the other temperature‐scheduled plots were significantly reduced below those of the WW plot. However, only about 50 to 60 mm of irrigation water were applied to these plots.
Yield and Yield Components of Four Spring Wheat Cultivars Grown Under Three Tillage Systems1
Authors: Ciha A. J. 
Published: July 2010

AbstractSoil erosion is a serious problem in the wheat (Triticum aestivum L.) producing areas of the Palouse Region of the Pacific Northwest. A field study was conducted under three environmental conditions [a Palouse silt loam (Pachic Ultic Haploxerolls, fine‐silty, mixed, mesic) during 1980 and an Athena silt loam (Pachic Haploxerolls, fine‐silty, mixed, mesic) during 1979 and 1980] to determine the effects of three tillage systems on grain yield and yield components of four soft white spring wheat cultivars, WS‐1, Urquie, Fielder, and Walladay. The tests were conducted using conventional (fall plow and spring disk), conservation (fall chisel and spring disk), and no‐tillage (standing stubble) tillage systems.Average grain yields with no‐tillage and conservation tillage were significantly greater than yields using conventional tillage. No‐tillage increased test weights while reducing tillage operations significantly reduced the number of spikelets per head, but increased the 100‐seed weight. Tillage practice had no significant influence on heads/m2, seeds per spikelet or seeds per head. Environment significantly influenced all yield components but not grain yield itself.There were significant differences in yield and yield components among the cultivars examined. Cultivar ✕ tillage interaction for yield (p ≤ 0.06) and test weight (p ≤ 0.03) were significant when examined across all environments. These findings show that no‐tillage spring wheat yields were equal to or greater than that obtained with conventional tillage. Significant cultivar ✕ tillage interactions for yield and test weight emphasize the need to evaluate individual spring wheat cultivars for specific tillage conditions.