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AbstractA new rapid method for the determination of actinides in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for samples up to 2 g in emergency response situations. The actinides in soil method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride soil matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA resin. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha sources are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency soil samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinides in soil results were reported within 4–5 h with excellent quality.

Previous studies of no‐till management in the Great Plains have shown that increased cropping intensity increased soil organic carbon (SOC). The objectives of this study were to (i) determine which soil C pools (active, slow, and passive) were impacted by cropping intensity after 12 yr of no‐till across potential evapotranspiration (PET) and slope position gradients; (ii) relate C pool sizes to the levels found in total SOC; and (iii) determine C pool sizes relative to C levels found in a grass treatment (G). Cropping systems were wheat (Triticum aestivum)‐fallow (WF), wheat‐corn (Zea maysL.)‐fallow (WCF), wheat‐corn‐millet (Panicum miliaceum)‐fallow (WCMF), and continuous cropping (CC) at three PET sites in Colorado. Active C (Soil microbial biomass C [SMBC]); and slow pool C (particulate organic matter C; POM‐C) increased as cropping intensity increased, dependent on PET. Passive C (mineral associated organic C [MAOC]) was strongly influenced by a site‐by‐slope position interaction but not by cropping system. Toeslope soils had 35% higher POM‐C compared with summits and sideslopes. All C pools were strongly correlated with total SOC, with the variability decreasing as C pool turnover time increased. Carbon pool sizes in cropping systems relative to levels found in G were independently influenced by cropping system. The highest were found in the CC system, which had 91, 78, and 90% of the amounts of C found in the perennial G system in the active, slow, and passive C pools, respectively.

Summer fallow (fallow) is still widely used on the North American Great Plains to replenish soil moisture between crops. Our objective was to examine how fallowing affects soil organic carbon (SOC) in various agronomic and climate settings by reviewing long‐term studies in the midwestern USA (five sites) and the Canadian prairies (17 sites). In most soils, SOC increased with cropping frequency though not usually in a linear fashion. In the Canadian studies, SOC response to tillage and cropping frequency varied with climate—in semiarid conditions, SOC gains under no‐till were about 250 kg ha−1yr−1greater than for tilled systems regardless of cropping frequency; in subhumid environments, the advantage was about 50 kg ha−1yr−1for rotations with fallow but 250 kg ha−1yr−1with continuous cropping. Specific crops also influenced SOC: Replacing wheat (Triticum aestivumL.) with lentil (Lens culinarisMedikus) had little effect; replacing wheat with lower‐yielding flax (Linum usitatismumL.) reduced SOC gains; and replacing wheat with erosion‐preventing fall rye (Secale cerealeL.) increased SOC gains. In unfertilized systems, cropping frequency did not affect SOC gains, but in fertilized systems, SOC gains often increased with cropping frequency. In a Colorado study (three sites each with three slope positions), SOC gains increased with cropping frequency, but the response tended to be highest at the lowest potential evaporation site (where residue C inputs were greatest) and least in the toeslope positions (despite their high residue C inputs). The Century and the Campbell et al. SOC models satisfactorily simulated the relative responses of SOC although they underestimated gains by about one‐third.

Soil organic C (SOC) has decreased under cultivated wheat (Triticum aestivum)‐fallow (WF) in the central Great Plains. We evaluated the effect of no‐till systems of WF, wheat–corn (Zea Mays)‐fallow (WCF), wheat–corn–millet (Panicum miliaceum)‐fallow, continuous cropping (CC) without monoculture, and perennial grass (G) on SOC and total N (TN) levels after 12 yr at three eastern Colorado locations. Locations have long‐term precipitation averages of 420 mm but increase in potential evapotranspiration (PET) going from north to south. Within each PET location, cropping systems were imposed across a topographic sequence of summit, sideslope, and toeslope. Cropping intensity, slope position, and PET gradient (location) independently impacted SOC and TN to a 5‐cm soil depth. Continuous cropping had 35 and 17% more SOC and TN, respectively, than the WF system. Cropping intensity still impacted SOC and TN when summed to 10 cm with CC > than WF. Soil organic C and TN increased 20% in the CC system compared with WF in the 0‐ to 10‐cm depth. The greatest impact was found in the 0‐ to 2.5‐cm layer, and decreased with depth. Soil organic C and TN levels at the high PET site were 50% less than at the low and medium PET sites, and toeslope soils were 30% greater than summit and sideslopes. Annualized stover biomass explained 80% of the variation in SOC and TN in the 0‐ to 10‐cm soil profile. Cropping systems that eliminate summer fallowing are maximizing the amount of SOC and TN sequestered.

Water is the principle limiting factor in dryland cropping systems. Surface soil physical properties influence infiltration and cropping systems under no‐till management may affect these properties through residue addition. The objectives of this study were: (i) to determine how cropping intensity and topographic position affect soil bulk density, porosity, sorptivity, and aggregate stability in the surface 2.5 cm of soils at three eastern Colorado sites; and (ii) to relate these properties to crop residue returned to the soil surface. No‐till cropping systems had been in place on three slope positions, at three sites, for 12 yr prior to this study. Wheat (Triticum aestivumL.)‐corn (Zea maysL.)‐fallow (WCF) and continuous cropping (CC) systems were compared with wheat‐fallow (WF) on summit and toeslope positions at two sites (Sterling and Stratton), and at the third site (Walsh) wheat‐sorghum [Sorghum bicolor(L.) Moench]‐fallow (WSF) replaced WCF. Cropping systems (CC and WCF or WSF) that returned more crop residue decreased bulk density and increased total and effective porosities compared with WF. Site and slope positions that produced more crop residue also improved these properties. However, sorptivity developed no significant differences as a result of cropping system. Macroaggregates made up a higher percentage of total aggregates in CC and WCF or WSF compared with WF in proportion to residue added and were also a function of clay content of the soil at different sites and slope positions. These factors enhance the potential for greater infiltration and hence greater water availability for crops.

Soil organic C (SOC) analyses using high temperature induction furnace combustion methods have become increasing popular because of advances in instrumentation. Combustion methods, however, also include C from CaCO3and CaMg(CO3)2found in calcareous soils. Separate analysis of the inorganic C (IC) must be done to correct C data from combustion methods. Our objective was to develop a efficient and precise IC method by modification of the pressure‐calcimeter method. We modified the method by using Wheaton serum bottles (20‐mL and 100‐mL) sealed with butyl rubber stoppers and aluminum tear‐off seals as the reaction vessel and a pressure transducer monitored by a digital voltmeter. Our gravimetric IC determination of six soils showed a strong correlation when regressed against IC from the modified pressure‐calcimeter method (slope of 0.99, r2= 0.998). The method detection limit (MDL) was 0.17 g IC kg−1for the 20‐mL serum bottles and the limit of quantification (LOQ) was 0.30 g IC kg−1The 100‐mL serum bottle had a MDL of 0.42 with a LOQ of 2.4 g IC kg−1When using a 100‐mL Wheaton serum bottle as the reaction vessel with a 0.50‐g sample size, soils containing up to 120 g IC kg−1, which represent a 100 % CaCO3equivalent, can be analyzed within the V output range of the pressure transducer. Soil organic C determined by subtraction of IC from total C from combustion analysis correlated well with SOC determined by the Walkley‐Black.

Effects of chemical treatment of cotton byproduct (CBP) on apparent digestibility, mineral balance, urine volume and pH and in vitrodigestibility were studied in three experiments with growing lambs and a rumen-fistulated steer. Apparent dry matter digestibility (DMD) and apparent organic matter digestibility (OMD) of total diets were increased (P<.01) by 35.4 and 35.7% in Exp. 1, and by 16.2 and 13.6% in Exp. 3. The CBP was treated with 4% (4 kg sodium hydroxide/96 kg CBP dry matter) sodium hydroxide (NaOH) and fed at 70% of the total dietary intake. Treatment of CBP with nitric and sulfuric acid increased (P<.01) both DMD and OMD 35% (Exp. 1). In Exp. 2, NaOH treatment decreased (P<.05) organic matter, cellulose and lignin content of CBP and increased (P<.05) ash content. In vitrodigestibilities of dry matter, organic matter and cell walls were increased (P<.05) by NaOH treatment. Volume of urine excreted by lambs in Exp. 1 and 3 was increased (P<.05) 53%, but urine pH was not affected by NaOH treatment. Acid treatment, however, resulted in a decrease (P<.01) in urine pH (9.4 vs5.3). Feeding NaOH-treated CBP at increasing percentages of the diet increased Na balance and decreased K, CI and Mg balance. NaOH-treated CBP had no effect on Ca or P balance. These results indicate that NaOH treatment of cotton byproduct increases apparent digestibility and that consumption of the treated product may increase the animal's requirement of K, CI and Mg. Furthermore, urine volume is increased but urine pH is not affected by NaOH treatment.

Soil and water conservation is essential to the sustainability of Great Plains dryland agriculture. We hypothesized that cropping intensification improves the efficient use of precipitation. We evaluated long‐term observations of soil water at three locations in eastern Colorado for a range of pan evaporations (1050–1900 mm), soils, and cropping systems. Soils at various locations were mostly of the Argiustoll subgroup except for one Ustochrept and one Haplargid, both at the higher evaporation location. Normal precipitation at the three locations ranges from 400 to 425 mm yr‐1. Systems included a 2‐yr winter wheat (Triticum aestivumL.)‐fallow (WF) and more intense 3‐yr winter wheat‐corn (Zea maysL.)‐fallow and winter wheat‐sorghum [Sorghum bicolor(L.) Moench]‐fallow and 4‐yr rotations. To quantify the effectiveness of the intensified systems at utilizing precipitation, we introduce the System‐Precipitation‐Storage Index (SPSI) and System‐Precipitation‐Use Index (SPUI). Mean SPSI values were 0.19 and 0.28 for 2‐ and 3‐yr systems, respectively, meaning that the fallow periods in the 3‐yr rotation were collectively 47% more efficient at storing precipitation than fallow in WF. Inclusion of a summer crop, such as corn or sorghum, increased the fraction of precipitation allocated to growing‐season crop production (i.e., SPUI) from 0.43 in WF to 0.56 (i.e., an increase of 30%) in 3‐yr systems. The gains in efficient use of precipitation with intensification resulted from (i) reducing the frequency of the inefficient fallow preceding wheat, and (ii) using water for transpiration that would otherwise be lost during fallow through soil evaporation, runoff, and deep percolation.

Finishing studies were conducted to compare feedlot performance and carcass traits with steers fed rations containing regular and waxy sorghum grain. Net energy values for maintenance (NEm) and gain (NEg) were determined for the rations and the grains from energy retention data determined by the comparative slaughter technique. The waxy grain contains glutenous starch which is almost entirely amylopectin and the regular grain non-glutenous starch composed of about 75% amylopectin and 25% amylose. The grains were dry rolled and fed in isonitrogenous rations containing in percent: grain, 83.9; cottonseed hulls, 10.0; cottonseed meal, 4.3; urea, 0.7; trace mineral salt, 0.5; CaCO3, 0.5; and elemental sulfur, 0.1. Feedlot performance and carcass traits were comparable between the two grains when expressed both on a live weight and carcass weight basis. Feed utilization was more efficient with the waxy grain both on a live weight (P<.10) and a carcass (P<.05) basis. NEmof the rations was 1.35 and 1.41 megcal. per kg., and of the grains 1.43 and 1.50 megcal. per kg. for the regular and waxy sorghum grains, respectively. NEgvalues were 0.86 and 1.10 megcal. per kg. for the rations, and 0.95 and 1.24 megcal. per kg. for the grains listed in the above order. These results suggest that the glutenous starch in the waxy grain provided a more readily available energy source than the non-glutenous starch in the regular sorghum grain.

The practice of finishing beef cattle in feedlots is growing rapidly in many sections of the United States. Difficulties in mechanization and transportation of roughages have caused these to be expensive and has stimulated interest in the use of fattening-type rations containing 90 to 100% concentrates. An important source of roughage in such rations has been cottonseed hulls, which are in short supply. Rice hulls, which are plentiful in supply, have not found ready use in livestock feeding because their use has sometimes caused harmful effects (Browne, 1904; Wahed, 1965; Feiger, Chopping and Tucker, 1947) in cattle fed high-roughage levels. Further work has indicated that ground rice hulls are not injurious to cattle (Rusoff, Frye and Epps, 1956) when the level does not exceed 30% of the diet. Recently, it was discovered that ground rice hulls, when heated in the presence of ammonia and catalysts, would absorb ammonia resulting in a product containing about 1.6% nitrogen.

Digestibility studies were conducted with sheep to determine the effects of various levels of office type waste paper fed as a roughage upon the nutritive value of 45% roughage rations. The paper was ground and incorporated into the rations at levels of 0, 15, 30 and 45%, replacing equal parts of Hegari forage sorghum (cane) hay by weight. The last ration contained paper as the only source of roughage. Urea was added to the rations as a nitrogen source when paper replaced each higher level of cane hay. All rations were fed at levels which were entirely consumed up to 1,000 gm. per animal daily during the 7-day adjustment period, then consumption held constant for the 7-day preliminary and collection periods.Average daily dry matter consumption of the rations containing 15 and 30% paper was equal to the control, and the ration containing 45% paper was consumed at a level of about 95% of the control. Digestibility of the energy components increased with each level of paper up to 30%, then remained almost constant when the paper level was increased to 45%. Crude protein digestibility was improved with 15% paper in the ration, then decreased until the ration containing 45% paper was equal to the control. True protein digestibility increased with the 15% paper ration, then held almost constant at the 30 and 45% levels of paper. Nitrogen retention was higher than the control with both the 15 and 30% paper levels, then decreased when the paper level was increased to 45%.The results of this study indicate that paper can successfully be used as a roughage source in ruminant rations. Digestibility of the energy components in paper was higher than those in cane hay, and protein digestibility was either improved or not appreciably affected when the various levels of paper were included as a roughage source in the ration.

Digestibility studies were conducted with sheep to investigate the effects of supplemental protein and energy upon the utilization of nutrients in 18-week regrowth kikuyu grass. The levels of supplemental protein were 0, 50 and 100 gm. of SBM per head per day, and the levels of energy supplementation were 0, 50 and 100 gm. of corn per head per day. The utilization of nutrients in both the total ration and in the grass portion of kikuyu grass grown under high rainfall, sub-tropical conditions were studied. Digestibility of organic matter, crude protein, nitrogen-free extract and gross energy increased in the total ration with each SBM level. Digestibility of organic matter, ether extract, nitrogen-free extract and gross energy in the total ration were improved by higher corn levels. Digestibility of crude protein and crude fiber in the grass portion decreased with higher corn levels. An increase in nitrogen retention was found with each higher level of both SBM and corn.

Digestibility studies were conducted with steers and wethers to determine the effects of three different processing methods upon the nutritive value of Maxigene 1877, a new feed-type wheat. The wheat was dry rolled, steam flaked and micronized flaked and fed in rations containing 78.2% grain, 20.0% cottonseed hulls, 0.8% molasses, 0.5% trace mineralized salt and 0.5% calcium carbonate. All rations were fed at levels of 6.81 and 1.05 kg per head daily for the steers and wethers, respectively. Percentage fine particles was highest in the steam flaked wheat followed by the micronized flaked and lowest in the dry rolled treatment. Digestibility of the energy components was comparable between the dry rolled and micronized flaked rations and both were significantly higher than the steam flaked ration. Protein digestibility of the rations was not significantly different among treatments, however the steam flaked ration was somewhat lower than the others. Nitrogen retention by sheep was increased (P<.01) by both heat processing methods. There were no significant processing method X species interactions. Digestibility of the energy components was comparable by steers and wethers with the dry rolled and micronized flaked treatments but higher with steers on the steam flaked ration. Protein digestibility was higher (P<.01) with cattle when comparicons were made with treatments combined. The largest differences in digestibility between species occurred within the steam flaked treatment for all nutrients. Digestibility of the grain portions calculated by differences followed similar trends as that with the rations in both treatment and species comparisons. These results indicate that dry rolled wheat was as digestible as steam flaked or micronized flaked wheat for steers and wethers.

Triticale was developed by crossing two genera of existing cereal grains, wheat and rye, and the name derived from the generic classifications of these grains (Triticum, wheat and Secale, rye). The earlier amphiploid triticales were Durum wheat × rye crosses and date back to the late 1800's. Plant breeders have since strived to develop tetraploid and hexaploid triticales that combine the more optimal characteristics of both wheat and rye. Extensive research has been conducted at the University of Manitoba over the past several years in development of higher yielding, more vigorous triticales (Briggle, 1969).Recently, several new hexaploid triticales have been developed and selected at the Jenkins Foundation for Research, Salinas, California. These new selections are progenies of crosses between bread-type wheats and triticales which represent considerable improvement in plant fertility, vigor and yields over earlier triticales, and yields of these improved triticales were also superior to either wheat or rye grown under similar conditions (B. C. Jenkins, personal communication).

Sheep digestibility and nitrogen retention trials were used for determining optimum autoclaving time of cold-hexane extracted cottonseed meal for maximum nitrogen retention. Portions of the meal were autoclaved under LOS kg./cm.2pressure for 30, 45, 60,75 or 90 min. It was found that between 45 and 75 min. of autoclaving time was required to produce a meal in which maximum nitrogen retention occurred.In trial 2 portions of dehulled cotton seed were subjected to live steam at atmospheric pressure (94° C.) for 0, 10, 20, 40, 60, 80 or 100 min., and then the oil was extracted with cold hexane. Nitrogen solubility decreased only slightly, but in a linear fashion, as heating time was increased. Using sheep it was found that the unheated meal had the highest protein digestibility and urinary nitrogen excretion, and the effect of heating on these criteria was expressed by a quadratic equation.

NEWSPAPER was evaluated and compared with sudan hay as a roughage in high concentrate finishing rations with heifers and in a digestibility trial with sheep fed 45% roughage rations. The newspaper was ground (1.27 cm screen) and fed in isonitrogenous, 10% roughage finishing rations at levels of 0, 3.3, 6.7 and 10.0% replacing equal portions of ground sudan hay by weight. Rations for the digestibility trial contained 45% roughage with the newspaper replacing sudan hay at levels of 0, 7.5, 15.0 and 30.0% by weight. Daily gains and voluntary feed intake were comparable for heifers fed the control and 3.3% newspaper rations and decreased (P<.05) with each of the two higher newspaper levels. Efficiency of feed conversion was reduced with each higher level of newspaper. These feedlot performance data were expressed by significant (P<.05) linear responses. Standard carcass traits and particularly those associated with finishing also decreased as newspaper levels increased. Digestibility of the major energy components decreased with each higher newspaper level and these reductions in digestibility were expressed by significant linear responses (P<.01). Protein digestibility was slightly lower at the 7.5 and 15.0% newspaper levels, and significantly (P<.01) reduced at the 30% level. Nitrogen retention tended to be lower with the rations containing newspaper. Dry matter, organic matter and gross energy digestibility of the newspaper determined by extrapolation to 100% were 29.5, 28.4 and 24.5%, respectively.

Soil samples can be contaminated with N by storage in bags described by the manufacturer to contain a wax laminated glassine liner (WLG). This study was conducted to compare samples stored in a WLG sample bag and a polyethylene bag (POLY). Sandy and clay loam soils were brought to three different moisture contents representing wet, moist, and dry, approximately 0.20,0.06, and 0.01 kg H20 kg−1soil, respectively, and stored in the WLG and POLY sample bags for 12, 48, and 120 h. Sample bags and soils were extracted for NH4−N and NO3−N with 2 MKCI. Extraction of shredded WLG and POLY bags gave 189.4 and 1.7 mg NH4−N kg−1bag, and 12.5 and 0.3 mg N03−N kg−1bag, respectively. Ammonium‐N concentration increased in both soils (from 4–42 mg N kg−1soil) when stored either moist or wet in the WLG bag. The moist clay loam and the wet sandy loam increased 9 and 15 mg NO3–N kg−1soil, respectively, when stored in the WLG bag for 120 h. The WLG bag should not be used for soil samples. All bags should be checked for N contamination prior to use.

Volunteer, wild stands of kochia (Kochia scoparia(L.) Schrad.) were harvested at three maturity stages to determine dry matter yield and composition and to evaluate kochia as a potential forage for livestock. The plants were in the prebloom stage of growth at the first cutting, mid‐bloom at the second, and full bloom at the third cutting. Dry matter yields and crude fiber levels increased and crude protein, percentage leaves, and. leaf: stem ratios decreased as stage of maturity advanced. Dry matter yields were 3,548, 8,708 and 11,327 ks/ha at the first, second and third stages, respectively. Crude protein ranged from 25.0 to 13.2%, and crude fiber from 17.9 to 37.0% of dry matter. Concentration of both macro and micro minerals either declined somewhat or remained almost constant as maturity progressed. These results suggest that kochia has high nutritive value as a forage for livestock, particularly in the earlier stages of growth.