bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Soil Nutrition with Poultry Litter Application in Low‐Input Forage Systems
Authors: McGrath Steve , Maguire Rory O. , Tracy Benjamin F. , Fike John H.
Published: January 2010

Despite high volumes of manure production in the Shenandoah Valley of Virginia, there are still areas of forage production that are nutrient deficient because manures have traditionally been applied to higher‐value row crops. This study was conducted to compare the effects of poultry litter and inorganic fertilizers on soil fertility and forage production. Two sites had the same treatments applied for two consecutive years: (1) split application of litter (half in spring and half in summer); (2) inorganic fertilizer at the same N, P, and K rates as Treatment 1; (3) single spring application of litter; (4) inorganic fertilizer at the same N, P, and K rates as Treatment 3; and (5) unfertilized control. Forage yield, soil pH, Mehlich 1 phosphorus (M1P), P uptake, and water‐soluble phosphorus (WSP) were measured during this experiment. On average, soil pH was 0.2 higher for litter than inorganic fertilizer treatments, but this difference wasn't significant. The M1P and WSP both increased throughout the 2 yr, but no significant differences were found among split and single application or litter and inorganic fertilizers. Fertilization increased yield 3.5 Mg ha−1 on average, and application timing and fertilizer types produced similar yields. The P balance revealed that, when using N‐based applications, neither site removed adequate P from forage yield to prevent environmental concerns. Our data showed that poultry litter was comparable with inorganic fertilizer in terms of increasing soil WSP, M1P, and forage yield, and the timing of application made no difference.
Forecasting Cotton Yield in the Southeastern United States using Coupled Global Circulation Models
Authors: Baigorria Guillermo A. , Chelliah Muthuvel , Mo Kingtse C. , Romero Consuelo C. , Jones James W. , O'Brien James J. , Higgins R. Wayne
Published: January 2010

We developed methods of forecasting cotton (Gossypium hirsutum L. var. hirsutum) yields at a county level 3 mo before harvest for the states of Alabama and Georgia. Cotton yield historical records for 57 counties were obtained from NASS and detrended using a low‐pass spectral filter. A Canonical Correlation Analysis regression‐based model was annually recalibrated to incorporate the year‐by‐year accumulating data: (i) April–June (during vegetative growth) observed rainfall for the forecasting year, and (ii) July–September (during reproductive growth) global‐scaled 2‐m mean temperatures for years before the forecasting year, beginning with 1970. We produced two types of forecasts: short range and medium range. The short‐range near‐term yield forecast (just before initiating harvest in the region) used gridded assimilated observed 2‐m mean temperatures obtained from the NCEP‐NCAR CDAS Reanalysis data. The medium‐range forecast (3 mo before harvest) used 2‐m mean temperature retrospective forecasts from the operational NOAA/NWS/NCEP Climate Forecasts System coupled global circulation model. The short‐range, near‐term forecast performance was measured by leave‐one‐out cross‐validation and retroactive validation, whereas medium‐range forecast performance used the previous two methods plus a proposed coral‐reef validation method. The agreement between short‐range near‐term forecast and actual cotton yield was statistically significant at the 0.05 level in 31 out of 57 counties. For 48% of these 31 counties, the agreements between medium‐range forecasts and actual cotton yields were statistically significant at the 0.05 level. The goodness‐of‐fit index for those 15 counties was 0.51 and the RMSE ranged from 13 to 31% of the annual yield.
Integrated Warm‐ and Cool‐Season Grass and Legume Pastures: I. Seasonal Forage Dynamics
Authors: Hudson Daniel J. , Leep Richard H. , Dietz Timothy S. , Ragavendran Ashok , Kravchenko Alexandra
Published: January 2010

High temperatures and scarce precipitation often cause the productivity and quality of cool‐season pastures in Southwest Michigan to decline for an extended period during the summer. This study was conducted to determine whether integration of switchgrass (Panicum virgatum L.) or big bluestem (Andropogon gerardii Vitm.) into cool‐season grazing systems would mitigate this period of low pasture productivity and quality. Cool‐season grass and legume pastures (CS‐Only) were compared to integrated big bluestem and cool‐season grass and legume pastures (CS‐BBS) and integrated switchgrass and cool‐season grass and legume pastures (CS‐SG). The seasonal dynamics of forage dry matter offered, crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) were used to compare the dynamics of the pasture productivity and quality in each of three treatments. Dry matter offered in the CS‐Only treatment was higher earlier in the grazing season and the peak in dry matter‐offered occurred between 20 and 30 d earlier in the CS‐Only treatment than in the other treatments. The seasonal trend for CP was generally higher and more constant for the CS‐Only treatment than for the CS‐BBS and CS‐SG treatments, which were very similar to each other. The seasonal trend for ADF and NDF was generally lower and more constant for the CS‐Only treatment than for the CS‐BBS and CS‐SG treatments, which were very similar to each other. These findings suggest that, compared to the CS‐Only treatment, the CS‐SG or the CS‐BBS treatments probably will not improve livestock gain or improve the distribution of animal grazing days throughout the summer.
Competitive Interactions between Cultivated and Red Rice as a Function of Recent and Projected Increases in Atmospheric Carbon Dioxide
Authors: Ziska Lewis H. , Tomecek Martha B. , Gealy David R.
Published: January 2010

Because wild lines of the same species often represent a weedy constraint to cultivated crops in the field, any differential response to atmospheric carbon dioxide concentration, [CO2], may alter weed–crop competition and seed yield. We evaluated the growth and reproduction of cultivated rice (Oryza sativa L.; Clearfield, CL161) and red or weedy rice (Stuttgart, StgS) in monoculture, and at two competitive densities (8 and 16 plants m−2) using [CO2] that corresponded to the 1940s, current levels, and that projected for the middle for the current century (300, 400, and 500 μmol mol−1, respectively). Competition was determined using plant relative yield (PRY) for biomass and seed yield as a function of [CO2]. At maturity, PRY significantly increased for wild rice, but decreased for the cultivated line as a function of competitive density. Increases in [CO2] resulted in significant decreases in the PRY of seed yield at both competitive densities for CL161; while significant increases in seed yield and aboveground biomass were noted for StgS, but only at the higher competitive density. In addition, the relative increase in seed yield for CL161–StgS, determined at the same competitive density, increased as a function of [CO2] suggesting a greater amount of seed rain from the weedy rice. Overall, these are the first data to indicate that for rice, weedy lines may have been favored as a function of rising carbon dioxide, with greater relative impact on the seed yield and biomass of cultivated rice lines.
Supplementation Strategies Effects on Performance of Beef Heifers Grazing Stockpiled Pastures
Authors: Vendramini Joao M. B. , Arthington John D.
Published: January 2010

The increased cost of inputs has led livestock producers in the southeastern United States to use alternative management practices to supplement beef cattle (Bos spp.) on pastures. The objective of this study was to evaluate the performance of beef heifers grazing stockpiled limpograss [Hemarthria altissima (Poir.) Stapf & C.E. Hubb.] pastures supplemented with cottonseed meal (CSM, Gossypium spp.) or grazing part‐time annual ryegrass (Lolium multiflorum Lam.). The experiment was conducted in Ona, FL, from February to April 2007 and 2008. Twelve 0.5‐ha limpograss pastures were stockpiled from October to February. Three heifers were assigned to each pasture. Treatments were three supplementation rates, 0, 1.1, and 2.2 kg head−1 d−1 of CSM, or part‐time grazing (PTG; 3 d wk−1) ryegrass. Limpograss herbage mass (HM) was greater in pastures where the heifers part‐time grazed ryegrass than in other treatments (2.1 vs.1.8 ± 0.1 Mg ha−1). Limpograss herbage accumulation rate (HAR; 24 ± 3 kg ha−1 d−1), crude protein (CP; 120 ± 10 g kg−1), and in vitro digestible organic matter (IVDOM; 500 ± 10 g kg−1) were similar among treatments. There was no difference in average daily gain (ADG) of heifers PTG ryegrass and supplemented with 2.2 kg CSM d−1 head−1 (0.67 vs. 0.64 kg d−1); however, 2.2 kg of CSM d−1 head−1 provided greater liveweight gain ha−1 (LWG; 291 vs. 188 kg ha−1). The PTG of ryegrass may be a viable supplementation option for beef cattle grazing stockpiled warm‐season grasses when concentrate is costly and the annual ryegrass grazing period extended.
Nitrogen Source and Rate Influence on Tall Fescue Quality and Nitrate Leaching in a Southern California Lawn
Authors: Wu Laosheng , Green Robert , Klein Grant , Hartin Janet S. , Burger David W.
Published: January 2010

In California, residential lawn area is second in planted acreage to production agriculture. Due to the demand for visually attractive lawns, relatively large amounts of N are often applied. The objective of this research was to investigate the effect of N source and application rate on tall fescue [Schedonorus phoenix(Scop.) Holub] visual quality and color, clipping yield, N uptake, and nitrate leaching under normal irrigation practices. Three annual N application rates (195, 293, and 390 kg ha−1) and four N sources (AN, ammonium nitrate; MUN, methylene urea; NON, natural‐organic nitrogen; and PCN, polymer‐coated nitrogen) were applied in four equal applications per year. The factorial experiment was replicated four times and conducted on a Hanford fine sandy loam at the University of California, Riverside's Turfgrass Research Facility from October 2002 to October 2004. Turfgrass visual quality and color ratings were evaluated every 2 wk. Clipping yield, clipping tissue total Kjeldahl nitrogen (TKN), and N uptake were measured or calculated in four 4‐wk growth periods per year. Suction lysimeters were used to collect soil water below the rootzone (leachate) to determine nitrate and ammonium concentrations once every two weeks. Soil nitrate and ammonium concentrations were analyzed at 12 and 24 mo. after initial fertilizer treatments. An annual N application rate of 195 kg ha−1produced an acceptable to good quality tall fescue lawn. Higher rates were not necessary, and increased nitrate leaching. Among the N sources, slow‐release N resulted in less nitrate leaching than the fast‐release N source.
Rotational Effects of Cuphea on Corn, Spring Wheat, and Soybean
Authors: Gesch R. W. , Archer D. W. , Forcella F.
Published: January 2010

Diversifying crop rotations can give economic and environmental benefits. Cuphea (Cuphea viscosissima Jacq. × C. lanceolata W.T. Aiton) is a new oilseed crop that grows well in the Corn Belt. However, little is known about its rotational effect on corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and spring wheat (Triticum aestivum L.), which are predominant crops in this region. A 4‐yr study conducted in Minnesota evaluated the previous crop effects of all 2‐yr rotational sequences of cuphea with corn, soybean, and wheat on crop yields and stands, soil water and N content, and production economics. Cuphea seed yield was unaffected by previous crop and yields of the other crops were unaffected by cuphea. Wheat stand was 17% greater and grain crude protein content 8% greater when following cuphea than following corn or soybean. This response was attributed to nitrate N remaining after cuphea harvest. Cuphea slightly negatively influenced soybean stands, but this was not reflected in yield. Cuphea production cost averaged $172 ha−1 less than corn and $118 and $126 ha−1 higher than soybean and wheat, respectively. While cuphea was not profitable at a price less than $1830 Mg−1, it could provide rotational benefits, with net returns for corn and soybean following cuphea comparable to other non‐monoculture sequences and higher than when grown continuously. However, the economic viability of including cuphea in rotation will be limited until the cuphea phase of the rotation can also be produced profitably. Cuphea agronomically fits in rotation with corn, soybean, or wheat, but may be best after soybean and before wheat or corn.
Response of Bt and Near‐Isoline Corn Hybrids to Plant Density
Authors: Coulter Jeffrey A. , Nafziger Emerson D. , Janssen Michael R. , Pedersen Palle
Published: January 2010

Transgenic Bt (Bacillus thuringiensis) corn (Zea mays L.) hybrids with resistance to corn rootworm (CRW; Diabrotica spp.) or European corn borer [ECB; Ostrinia nubilalis (Hübner)] can have greater tolerance to water and nutrient stress, and thus may have higher optimum plant densities. Experiments were conducted following soybean [Glycine max (L.) Merr.] over nine site‐years in Illinois to determine whether the response to plant density for corn grain yield and net return to seed cost differ among near‐isoline hybrids with no insect resistance, Bt resistance to CRW, or Bt resistance to CRW plus ECB. Similar experiments were conducted over three site‐years in Iowa following both soybean and corn for near‐isoline hybrids with Bt resistance to ECB or ECB plus CRW. Larval CRW injury was low in Iowa and stalk lodging was minimal in all experiments. Across site‐years in Illinois and in both crop sequences in Iowa, grain yield and net return to seed cost were not affected by hybrid. Net return to seed cost within $2.50 ha−1 of the maximum occurred with densities of 76,300 to >98,600 plants ha−1 following soybean in Illinois, 87,100 to 93,400 plants ha−1 following soybean in Iowa, and 87,400 to 95,700 plants ha−1 following corn in Iowa. Yields within these optimum plant densities were 15.9, 16.1, and 15.4 Mg ha−1, respectively. When CRW and ECB are managed or are at low levels, optimum plant density is similar between hybrids with or without resistance to these pests.
SOYPOD: A Model of Fruit Set in Soybean
Authors: Egli Dennis B.
Published: January 2010

The soybean [Glycine max (L.) Merr.] plant matches its reproductive potential to environmental conditions by adjusting the number of fruits and seeds that it produces. This adjustment is an important, but not well understood, part of the yield production process. Developing a model of fruit set will contribute greatly to a better understanding of the determination of fruit number and yield. The model (SOYPOD) is based on the well documented principle that fruit number is related to assimilate availability during flowering. Inputs, including daily photosynthesis, flower production, and potential pod and seed growth rates, were taken from field and greenhouse experiments. Fruit survival at an isolated node was determined by comparing the daily assimilate supply with the assimilate requirement of the developing fruits, which are sensitive to supply only until the pod wall reaches its maximum size. Abortion occurs when the fruit does not receive assimilate for ABRTM consecutive days during the sensitive period (SEN). The most mature fruits receive assimilate first when assimilate is limiting. It was possible to find realistic combinations of ABRTM and SEN that mimicked the curvilinear response of fruit number to increasing assimilate supply observed in planta. Increasing the individual seed growth rate decreased fruit number when the assimilate supply was held constant, as it does in planta. SOYPOD accurately mimics the fruit set process at isolated nodes in soybean suggesting that it can be used as the basic building block of a whole plant model.
Critical Grain and Stover Nitrogen Concentrations at Harvest for Summer Maize Production in China
Authors: Chen Xinping , Zhang Fusuo , Cui Zhenling , Li Junliang , Ye Youliang , Yang Zhiping
Published: January 2010

A uniform critical N concentration is desirable to serve as an indicator of N status and to guide agricultural practice and regulation. Our objective was to evaluate whether grain and stover N concentrations in summer maize (Zea mays L.) at harvest can serve as indicators of N status, and to determine a critical grain and stover N concentration (CGNC and CSNC) for maize production in China. At optimal nitrogen rate (ONR), grain N concentration was close to maximum, while stover N concentration was significantly lower, as calculated using a linear plus plateau model. Soil residual nitrate N content after harvest and N losses for maximum stover N concentration increased by 32 and 42 kg N ha−1, as compared to values with ONR. Based on 141 on‐farm N response experimental sites, CGNC and CSNC were 12.6 ± 0.6 g kg−1 (± CL0.05) and 8.1 ± 0.8 g kg−1 g kg−1, respectively. An evaluation across 122 on‐farm sites indicated that 70 and 66% of sites had grain and stover N concentrations less than the CGNC and CSNC at deficient (0 N control) N supply. When N was supplied in excess, 54% of sites had stover N concentrations greater than CSNC while only 14% of sites had grain N concentrations greater than the CGNC. This region wide study concluded that critical N concentrations were useful indicators of N deficiencies in maize production, but were less than reliable as indicators of excess N fertilization, in particular for grain N concentration.
Optimizing Stocking Rate for Maximum Return to a Wheat–Cattle Enterprise Using Model Simulation and Economics
Authors: Zhang X.‐C.
Published: January 2010

Managing dual‐purpose wheat is complex because of the tradeoff relationship between cattle (Bos taurus) and wheat (Triticum aestivum L.) production. Stocking rate (SR) and planting date are key decision variables of the dual systems. The objective was to develop decision support information that help farmers boost profits by adapting SR and planting date to particular production and market conditions. A wheat grazing model was used to simulate the systems for seven SR (0–3 head ha−1), five planting dates, three climate scenarios, and two initial soil moisture profiles. Net returns were estimated for three representative markets. Net returns under optimized management doubled those under the business‐as‐usual for the comparable planting dates, indicating great potentials to boost net returns with better management. Optimal SR depends on markets and forage availability. For market that overwhelmingly favors grain production, grain‐only wheat should be used; whereas dual‐purpose wheat is preferred under other market conditions. For wet soil at planting, maximum returns are attained in early September planting at high SR of > 2 head ha−1 despite climates; however, the high optimal SR should be adjusted down with delayed planting in wet and average but maintained in dry climate for water conservation. For dry profile at planting, optimal management is dual‐purpose wheat with SR of 3 in wet, grain‐only wheat in average, and fallow in dry climate. Had wheat been established in severely dry years, moderate grazing at 0.5 to 1.5 SR could reduce net losses. Under most circumstances, grazing should not be allowed to pass first hollow stem to maximize returns.
Response of Upland Rice Cultivars to Nitrogen Fertilizer in the Savannas of Nigeria
Authors: Kamara Alpha Y. , Ekeleme Friday , Omoigui Lucky O. , Oikeh Sylvester O. , Chikoye David , Tegbaru Amare
Published: January 2010

In the dry savannas of West Africa, cultivation of upland rice (Oryza spp.) under rain‐fed conditions is expanding due to the introduction of the New Rice for Africa (NERICA; WARDA, Bouake, Cote d'Ivoire) but appropriate N recommendations for these new cultivars are lacking. The present study evaluated the response of four NERICA rice cultivars, their parents (WAB 56‐104 (O. sativa, tropical japonica type), CG 14 [O. glaberrima]) to four rates of N (0, 30, 60, and 90 kg ha−1) at Sabon‐Gari (Sudan savanna, SS) and Tilla (northern Guinea savanna, NGS) in 2007 and 2008. There was no interaction between N rates and rice cultivars for grain yield, suggesting that the rice cultivars responded similarly to N application. Grain yield of NERICA rice cultivars responded significantly to N application in the Nigerian dry savannas following a linear response, even at 90 kg N ha−1, thus optimum rate might be above this N level. NERICA 1, NERICA 3, and NERICA 4 had comparable yields and produced 1.4 to 1.7 times more grains than the other cultivars in Sabon‐Gari; while in Tilla, NERICA 4 and WAB56‐104 produced the highest yield. NERICA 1, NERICA 3, and NERICA 4 may be more suitable for cultivation in Sabon‐Gari (SS) while NERICA 4 and WAB56‐104 can be recommended for Tilla (NGS).
Conservation versus Conventional Tillage on Performance of Three Different Crops
Authors: Yau S. K. , Sidahmed M. , Haidar M.
Published: January 2010

Conservation tillage, besides being more economical, prevents soil erosion and has other beneficial effects on our environment, but few studies have been conducted on differential responses of different crops to conservation tillage. The main objective of this study was to examine the interaction of tillage with crop species. Rainfed field experiments in a strip‐plot design with four replicates were conducted in the semiarid, central Bekaa Valley of Lebanon for 2 yr. There were three tillage treatments: conventional (CT), minimum (MT), and no tillage (NT). Crops studied were barley (Hordeum vulgare L.), chickpea (Cicer arietinum L.), and safflower (Carthamus tinctorius L.). The experiment was initiated in 2005–2006 on a field in which CT was practiced for years. In 2006–2007, the experiment was conducted on the exact site following the same 2005/2006 randomization. In each year, NT had similar weed density and dry weight m−2 as CT, and mean weed infestation over years was lower in CT and NT than in MT. Year × tillage × crop interaction was significant for plant height in April, days to flowering/heading, seed yield, and harvest index. Tillage × crop interaction existed for seed and straw yields, harvest index, and plant height at maturity. Barley yielded poorer in NT than in CT, but similar yields were obtained in NT and CT for chickpea and safflower, suggesting that the tap root system of chickpea and safflower may be more adapted to NT than the fibrous root system of barley. Results of this study could be used to organize demonstration trials to help encouraging farmers to try practicing NT.
Equivalency of Broiler Litter to Ammonium Nitrate as a Cotton Fertilizer in an Upland Soil
Authors: Tewolde H. , Adeli A. , Sistani K. R. , Rowe D. E. , Johnson J. R.
Published: January 2010

Estimates of litter value based on crop yield equivalency to inorganic fertilization may reflect the actual value of litter more accurately than estimates based on its N, P, and K content. The primary objective of this research was to identify a rate of broiler litter that results in cotton lint yield equivalent to inorganic N fertilization and to estimate litter value based on this yield equivalency. The research was conducted in northern Mississippi in 2002 to 2004 in a Loring silt loam upland soil. Cotton was fertilized with six broiler litter rates ranging between 2.2 and 13.4 Mg ha−1 or six NH4NO3–N rates ranging between 34 and 168 kg ha−1 or was not fertilized. Lint yield calculated based on fitted models peaked at 1033 kg ha−1 when cotton was fertilized with 94 kg ha−1 NH4NO3–N, which is similar to the 90 kg N ha−1 local recommendation. Lint yield of cotton fertilized with litter (8.7 Mg ha−1) peaked at 1156 kg ha−1, which is a 123 kg ha−1 lint yield increase over NH4NO3–N. The economic optimum NH4NO3–N rate was 72 kg ha−1, which produced 88 kg ha−1 less lint than the economic optimum litter rate of 5.2 Mg ha−1 Fertilization with 3.7 Mg ha−1 litter produced lint yield equivalent to the locally recommended 90 kg ha−1 NH4NO3–N. The N fertilizer replacement value of litter calculated based on this equivalency exceeded the value calculated using the traditional method by ≈27%. These results overall show that fertilizing cotton in this soil with litter increased lint yield above that possible with conventional inorganic fertilization by 12% and that broiler litter is substantially more valuable than can be estimated from its N, P, and K contents.
Rate and Timing of Potassium Fertilization and Fungicide Influence Rice Yield and Stem Rot
Authors: Maschmann Elliot T. , Slaton Nathan A. , Cartwright Richard D. , Norman Richard J.
Published: January 2010

Potassium deficient rice (Oryza sativa L.) is susceptible to diseases including stem rot (Sclerotium oryzae Catt.). Knowledge of how to manage K deficiency and the increased disease susceptibility is necessary to reduce rice yield losses. Our objectives were to determine the influence of K rate, application time, and azoxystrobin fungicide on grain yield and stem rot index (SRI) of rice grown on soils with low K availability. Muriate of potash was applied at 0, 56, and 112 kg K ha−1 to rice preflood (PF), panicle differentiation (PD), or the late boot (LB) stage. Azoxystrobin fungicide was applied at 0 and 0.23 kg a.i. ha−1 following the PD K application. Stem rot was assessed at maturity and expressed as SRI on a 1‐to‐5 scale, with 1 indicating no disease symptoms (healthy) and 5 being a dead culm. Potassium fertilization increased grain yield by 8 to 11% above rice receiving no K. Within each K application time, grain yield of rice receiving 0.23 kg ha−1 azoxystrobin was 6 to 12% greater than rice receiving no azoxystrobin. Within each azoxystrobin rate, rice yields were lowest when no K was applied, intermediate for K applied at LB, and greatest for K applied PF or PD. The average SRI was reduced significantly by K fertilization and azoxystrobin application. Potassium fertilizer applied between PD and LB can reduce yield losses from K deficiency. Sufficient K fertilizer should be applied PF to prevent potential yield losses from K deficiency and minimize stem rot incidence and severity.
Determining Aluminum Tolerance and Critical Soil pH for Winter Canola Production for Acidic Soils in Temperate Regions
Authors: Lofton J. , Godsey C. B. , Zhang H.
Published: January 2010

A growing interest in winter canola (Brassica napus L.) across the southern Great Plains has brought about many issues regarding production. One of the issues to be addressed is winter canola's tolerance of Al when grown on acid soils. The objectives of this study were to determine the maximum Al concentration and minimum pH for canola production in a temperate region with a known acid soil problem. To evaluate this, a field experiment was conducted in north‐central Oklahoma comparing eight different commercially available winter canola cultivars over an existing pH gradient (ranging from pH 4.0–6.5). In addition to the field study, a laboratory study was conducted to screen the same eight cultivars in the lab for tolerance to Al. In the field study, winter canola seed yield decreased linearly below a soil pH of 5.8, which corresponded to a KCl‐exchangeable Al concentration of 11 and 15 mg kg−1 for 2007 and 2008, respectively. Laboratory screening results indicated that winter canola root growth was reduced when Al concentrations of 20 mg L−1 were present. Consideration will have to be given to soil pH to optimize winter canola seed yield in the southern Great Plains and other temperate regions.
Methods to Improve Seed Yield of Leymus chinensis based on Nitrogen Application and Precipitation Analysis
Authors: Wang J. F. , Xie J. F. , Zhang Y. T. , Gao S. , Zhang J. T. , Mu C. S.
Published: January 2010

Optimum methods to improve perennial grass seed yield are crucial for agronomic practices. Tzvel [Leymus chinensis (Trin.)] seed yield was examined in field experiments from 2005 to 2007 to determine the effects of N application timing (i.e., double‐ridge stage, spikelet initiation stage, and later seed‐filling stage) and rates (0, 60, 120 kg ha−1) under different precipitation conditions. Meanwhile, the relationship of successive 5‐yr precipitation and temperature data and spike number was analyzed. Application times and rates of N did not affect the heading percentage or spike number per square meter, but they were only influenced by year. A strong correlation existed between spike number and rainfall at the after seed‐maturing stage during the previous growing season. In contrast to controls, the seed setting percentage, seed number per spike, and thousand seeds weight increased significantly when the highest N rates were applied at the double‐ridge stage. These results suggest that the yield components were decided by two critical stages: the after seed‐maturing stage of the previous year and the double‐ridge stage of the current year. Among seed yield components, the spike number is the most important component, the importance of seed number per spike and thousand seeds weight is less than spike number. Therefore, to improve seed yield, we first recommend methods of watering at the after seed‐maturing stage in the previous growing season, and then applied N at double‐ridge stage in the current year.
Peppermint Productivity and Oil Composition as a Function of Nitrogen, Growth Stage, and Harvest Time
Authors: Zheljazkov Valtcho D. , Cantrell Charles L. , Astatkie Tess , Ebelhar M. Wayne
Published: January 2010

The commercial production of peppermint (Mentha × piperita L.) is concentrated in more northern latitudes worldwide (north of the 41st parallel), including the United States. This 2‐yr field study in Mississippi evaluated the effect of N (0, 80, and 160 kg/ha), growth stage (bud formation and flowering), and harvest time or cut (first cut in mid‐July, second cut beginning of October) on peppermint yields, oil content, and composition. Biomass and oil yields were higher from the first cut than from the second. Overall, N increased biomass and oil yields. Contrary to literature reports that peppermint requires long days north of the 41st parallel to reach flowering, peppermint in Mississippi (at 34°43′22″ N lat) did reach flowering. The average oil yields at bud formation and at flowering were 165 and 122 kg/ha, respectively, and were greater than the average peppermint essential oil yields for the United States in 2008. Generally, (–)‐menthol concentration in the oil from the 2007 harvest was lower than in the oil from the 2008 harvest. The average (–)‐menthol concentration in the oil from the fertilized plots harvested at flowering in 2008 was 43 to 46%, but (–)‐menthol in the other treatments was below 37%. Our results suggest the first harvest in Mississippi should be delayed until the end of July to promote conversion of (–)‐menthone to (–)‐menthol. Peppermint could provide two harvests per growing season under the Mississippi climate, with oil yields and composition similar to those from other peppermint production regions.
Productivity, Oil Content, and Composition of Two Spearmint Species in Mississippi
Authors: Zheljazkov Valtcho D. , Cantrell Charles L. , Astatkie Tess , Ebelhar M. Wayne
Published: January 2010

‘Scotch’ (Mentha × gracilis Sole) and ‘Native’ (Mentha spicata L.) spearmints are grown in the northern United States, but have not been evaluated in the Southeast. Two‐year field studies were conducted in Mississippi at two locations (Verona and Stoneville) to evaluate the effects of N application rate and cut (harvest time) on yields, essential oil contents, compositions, and the yield of individual oil constituents [(–)‐carvone, (R)‐(+)‐limonene, and eucalyptol] in Scotch and Native spearmints. Application of N at 80 and 160 kg/ha increased herbage and oil yields in Scotch, suggesting that commercial Scotch plantations should be provided with 160 kg N/ha. Native spearmint provided similar herbage yields when fertilized with 80 or 160 kg N/ha, but the higher N rate increased oil yields. The essential oil yields in this study were higher than the average oil yields for spearmint grown in the United States during 2008. The essential oil composition of Scotch and Native spearmints grown in Mississippi were similar to the oil produced in other states and other regions in the world. At the Verona site, the average (–)‐carvone concentration in the essential oil of Scotch was 68 to 75%, whereas the concentration of (–)‐carvone in Native oil ranged from 59 to 62%. At Stoneville, the average (–)‐carvone concentration in Scotch oil was 74%, whereas (–)‐carvone in Native oil was 68 to 74%. Both Scotch and Native spearmints could be grown as essential oil crops in Mississippi and possibly in other areas of the southeastern United States.
Living Mulch Nutritive Value in a Corn‐Soybean‐Forage Rotation
Authors: Singer Jeremy W. , Moore Kenneth J.
Published: January 2010

Living mulches can function to supply forage in multifunctional cropping systems. Information quantifying nutritive value of forage plants in living mulch cropping systems is limited. The objective of this research was to quantify the nutritive value of forages from different plant functional groups managed as living mulches in 2 of 3 yr and as a forage crop in the third year of this 3‐yr corn (Zea mays L.)‐soybean [Glycine max (L.) Merr.]‐forage rotation. Alfalfa (Medicago sativa L.), Kura clover (Trifolium ambiguum M. Bieb.), and birdsfoot trefoil (Lotus corniculatus L.) were evaluated in sole seedings and binary mixtures, reed canarygrass (Phalaris arundinacea L.) and orchardgrass (Dactylis glomerata L.) were included in three‐way mixtures, and a nondormant alfalfa was seeded each spring for comparison as a control. Average crude protein (CP) and neutral detergent fiber (NDF) during 2005, 2006, and 2007 was 190 and 449 g kg−1 for Kura + alfalfa + reed canarygrass compared with 182 and 458 g kg−1 averaged across birdsfoot trefoil + alfalfa + orchardgrass and Kura + alfalfa + orchardgrass mixtures, 195 and 397 g kg−1 averaged across alfalfa, Kura + alfalfa, and alfalfa + birdsfoot trefoil, and 193 and 404 g kg−1 for the nondormant alfalfa treatment. Weed densities averaged 104, 178, and 116 weeds m−2 in 2005, 2006, and 2007 among living mulch treatments compared with 14, 84, and 67 weeds m−2 in the nondormant alfalfa. Despite high weed densities in the living mulch treatments, no specific treatment effect was detected for nutritive value. All of these living mulch treatments produced high nutritive value forage.
Eastern Gamagrass Management for Pasture in the Mid‐Atlantic Region: I. Animal Performance and Pasture Productivity
Authors: Burns J. C. , Fisher D. S.
Published: January 2010

Eastern gamagrass [Tripsacum dactyloides (L.) L.] (EG) is a native, warm‐season perennial grass with potential as pasture for the eastern United States, but its value has not been well studied. The objective of this 4‐yr experiment was to estimate forage mass (FM) for EG that maximizes steer (Bos taurus) performance and pasture productivity. Five treatments (three continuously and two rotationally stocked) were compared with a continuously stocked ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] control. The three continuously stocked treatments had mean FM (10‐cm stubble) levels of 559 kg ha−1 (Short), 1103 kg ha−1 (Medium), and 1932 kg ha−1 (Tall). Rotational treatments consisted of two subdivisions with steers moved on a 10 to 14 d interval (FM = 1348 kg ha−1) and10 subdivisions with steers moved every 3 to 4 d with a 27 to 36 d regrowth interval (FM = 2061 kg ha−1). The average daily gain (ADG) from the Medium continuously stocked treatment was greatest at 0.90 kg (P = 0.02) and produced similar annual gain per hectare (735 vs. 749 kg ha−1; P = 0.08) as Short. Rotational pastures had greater FM than continuously stocked (1705 vs. 1198 kg ha−1; P = 0.03), but the least ADG (0.67 vs. 0.79 kg; P = < 0.01). Bermudagrass produced less ADG than EG (0.57 vs. 0.79 kg; P < 0.01), but gain per hectare was similar (662 kg ha−1) and stocking rate was greater (10.0 vs. 6.7 head ha−1; P < 0.01). Eastern gamagrass has potential as a special purpose pasture for the region when greater ADG is the goal.
Determination of a Critical Nitrogen Dilution Curve for Spring Wheat
Authors: Ziadi Noura , Bélanger Gilles , Claessens Annie , Lefebvre Louis , Cambouris Athyna N. , Tremblay Nicolas , Nolin Michel C. , Parent Léon‐Étienne
Published: January 2010

Plant‐based diagnostic tools of N deficiency can be based on the concept of critical N dilution curves describing whole‐plant critical N concentration (Nc; g kg−1 of dry matter [DM]) as a function of shoot biomass (W; Mg DM ha−1). This has been tested for several crops, including winter wheat (Triticum aestivum L.) but has not been tested for spring wheat. Our objectives were to determine a critical N dilution curve specific to spring wheat, to compare this curve with existing critical N dilution curves for winter wheat, and to assess the plausibility of using it to estimate the level of N nutrition. The study was conducted at six site‐years (2004–2006) in Québec, Canada, with four to eight N fertilization rates (0–200 kg N ha−1). Shoot biomass and N concentration were determined on five to eight sampling dates during the growing season, and grain yield was measured at harvest. A critical N dilution curve (Nc = 38.5 W−0.57) was determined for spring wheat and was different from those reported for winter wheat. The N nutrition index (NNI = Nobserved/Nc) calculated from this spring wheat critical N dilution curve was significantly related (R2 = 0.70; P < 0.001) to relative grain yield. This critical N dilution curve and the resulting NNI adequately identified situations of limiting and nonlimiting N nutrition and could be used to establish the N nutrition status.
Dryland Performance of Sweet Sorghum and Grain Crops for Biofuel in Nebraska
Authors: Wortmann C. S. , Liska A. J. , Ferguson R. B. , Lyon D. J. , Klein R. N. , Dweikat I.
Published: January 2010

Sweet sorghum [SS; Sorghum bicolor (L.) Moench] is a potential biofuel crop for the Great Plains. Sweet sorghum was compared with corn [Zea mays (L.)] and grain sorghum for potential ethanol yield, energy use efficiency, and greenhouse gas (GHG) emissions at seven dryland site‐years in Nebraska. Seasonal rainfall ranged from approximately 340 to 660 mm. Soils were deep with medium texture at all site‐years. The effects of seeding rate, N rate, and cultivar on SS performance were evaluated. Sweet sorghum sugar yield was not affected by seeding rate and N application at six of seven site‐years, but yield was increased by 19% at one site‐year. Calculated ethanol yield and net energy yield were 33 and 21% more, respectively, with the grain crops compared with SS, but mean net energy yield of an earlier‐maturing SS cultivar was comparable with the grain crops. The mean ratio of energy produced in ethanol per total energy invested was 23% less for grain crops compared with SS. Mean life cycle GHG emissions were 53% and 66 to 69% less compared with gasoline for SS and grain crops, respectively. Very efficient use of the ethanol coproducts was assumed for the grain crops while SS bagasse was assumed to be returned to the field. At least one SS cultivar is competitive with grain crops for some biofuel criteria, but SS is not competitive with grain crops for total or net liquid transportation fuel produced per hectare.
Drought Stress Responses and Recovery of Texas × Kentucky Hybrids and Kentucky Bluegrass Genotypes in Temperate Climate Conditions
Authors: Merewitz Emily , Meyer William , Bonos Stacy , Huang Bingru
Published: January 2010

Turf quality (TQ) decline due to drought is a major concern in cool‐season turfgrass management. The study was conducted to examine whether selected Texas (TBG) × Kentucky bluegrass (KBG) hybrids (HBGs) (Poa arachnifera Torr. × P. pratensis L.) exhibit improved drought stress tolerance and recuperative ability in comparison to commonly‐used KBG (P. pratensis) genotypes. Plant material included two HBG selections (HBG568 and HBG668), two commercially‐available HBGs (‘Thermal Blue’ and ‘Bandera’), and two KBG genotypes (‘Midnight’ and ‘Baron’). The experiment was conducted in field plots covered with a rainout shelter in 2006 and 2007 in North Brunswick, NJ. Treatments consisted of (i) well‐watered controls; (ii) drought stress (withholding irrigation) from June to August; and (iii) recovery (rewatering after a period of drought stress) in September and October. The HBGs Thermal Blue and Bandera generally did not show significant difference in turf growth from the two KBG genotypes in both years. HBG568 maintained significantly higher TQ, relative water content (RWC), cell membrane stability, and canopy density estimated as the reflectance ratio of infrared to red (IR/R, leaf area index) and normalized difference vegetation index (NDVI), compared with the two KBG genotypes and other HBGs following a prolonged period of drought stress (after 20 d of treatment) on most sampling dates in both years. HBG568 exhibited more rapid recovery of TQ, IR/R (IR935/R661), NDVI, and sod tensile strength than the other genotypes in both years, while HBG668 also had better recovery in 2007. The results demonstrate genetic variation in drought stress tolerance and recovery among HBGs and KBGs and the potential for the development of HBGs with improved tolerance to drought stress and performance during recovery.
Eastern Gamagrass Management for Pasture in the Mid‐Atlantic Region: II. Diet and Canopy Characteristics, and Stand Persistence
Authors: Burns J. C. , Fisher D. S.
Published: January 2010

Eastern gamagrass [Tripsacum dactyloides (L.) L.] (EG), a native warm‐season perennial grass, lacks evaluation for use in grazing systems. Our objective was to test EG in a 4‐yr experiment to estimate forage mass (FM) that maximizes steer (Bos taurus) performance and pasture productivity. Pasture canopy characteristics, diet selection by grazing steers, and stand persistence from EG continuously grazed at Short, Medium, and Tall heights and two rotationally stocked treatments were compared with continuously stocked ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] (BG). The EG had proportionally more green leaf (78.2 vs. 24.5%), less stem (4.4 vs. 45.2%), less heads (0.4 vs. 5.6%), and similar dead tissue (17.0 vs. 24.8%). Plant fractions were similar in proportion among EG treatments. Digestible leaf mass was greater in EG than in BG (P < 0.01; 713 vs. 292 kg ha−1) and dominated the EG canopies with a linear (P < 0.01) increase in leaf mass with increasing FM (194–922 kg ha−1). Diets were similar in IVTOD (738 g kg−1), CP (151 g kg−1), and NDF (654 g kg−1) when continuously stocked but greater (P < 0.01) in IVTOD (791 g kg−1), and least in NDF (624 g kg−1) from the rotation. Stand declined linearly (P = 0.09) with decreasing FM (Tall = 34.5 and Short = 11.7% basal cover) but was similar between the two rotational systems (35.5%). Continuously stocking EG at about 38 cm gave greatest steer daily gain but rotations may prevent declines in stands with some sacrifice in gains.
Hormesis, Adaptive Epigenetic Reorganization, and Implications for Human Health and Longevity
Authors: Vaiserman Alexander M.
Published: January 2010

Hormesis is a common phenomenon in a number of biomedical areas. However, the basic nature of this phenomenon remains largely unknown. Therefore, significant uncertainty is inevitable in attempts to apply hormesis as a pro-health and anti-aging tool. Evidence supporting that hormetic-like effects may be the result of a generalized whole-organism adaptive epigenetic response is reviewed. Specific hormesis-inducing interventions during development would allow to achieve an optimal balance between activation and repression of various genes and thus to prevent age-related degenerative diseases and slow aging. The reasons that oscillating temperature mild stress could potentially be used for human application are discussed.
Impacts of Climate Change on Biodiversity Resources & Forest Ecosystems
Authors: Thakur Ram B , Phulara Nirmala K
Published: January 2010

Climate Change is a key challenge of biodiversity conservation. Impacts of climate change are significant on physiology, phenology and distribution of species, seasonal biological phenomenon of floral and faunal species, animal life cycle, migratory birds and wild animals, mountain ecosystems, wild animals' habitat as well as coral reefs habitat. Moreover, impacts of climate change are also on preservation of wild animals and plants in protected areas, shifting of bio-climatic zones, endangered & vulnerable flora and fauna and biodiversity hotspots. The change in hydrological cycle due to global warming affect on river run-off, accelerate water-related hazards and affect also on agriculture, vegetation, forests, biodiversity and health. Key Words: Carbon sequestration, Seasonal biological phenomenon, Shifting bio-climatic zones, Biodiversity hotspots   DOI: 10.3126/init.v3i0.2499 The Initiation Vol.3 2009 p.86-96
Technical parameters affecting grain refinement by high pressure torsion
Authors: Hohenwarter Anton , Bachmaier Andrea , Gludovatz Bernd , Scheriau Stephan , Pippan Reinhard
Published: January 2010

High pressure torsion is a well known and widespread processing technique for severe plastic deformation. The aim of high pressure torsion and other comparable techniques is to obtain ultrafine-grained or even nanocrystalline materials with enhanced mechanical and physical properties compared with their coarse-grained counterparts. Generally this refinement process is strongly influenced by processing parameters such as temperature or accumulated strain, but can also simply be affected by the entire experimental setup. Therefore, the benefits and limitations of the process with regard to grain refinement, homogeneity and specimen size, underlined with experimental results using different tools, will be discussed.
Grain refinement and growth induced by severe plastic deformation
Authors: Wang Yanbo , Liao Xiaozhou , Zhu Yuntian
Published: January 2010

Severe plastic deformation techniques have been widely used to produce bulk ultrafine-grained and nanocrystalline materials. Severe plastic deformation of materials is a complex process that includes both grain refinement via the activities of dislocations and twinning, and grain growth. In this paper, we present a short review on the mechanisms of grain refinement and grain growth induced by severe plastic deformation.
Ductility of ultrafine-grained copper processed by equal-channel angular pressing
Authors: Zhao Yonghao , Li Ying , Topping Troy D. , Liao Xiaozhou , Zhu Yuntian , Valiev Ruslan Z. , Lavernia Enrique J.
Published: January 2010

In a previous study (R.Z. Valiev et al.: J. Mater. Res. 17 (2002) 5), unusual combinations of yield strength and ductility in ultrafine grained copper processed by equal-channel angular pressing of 360 MPa 23 % (by Bc route two passes) and 380 MPa 55 % (by Bc route 16 passes) were reported. However, results from recent work suggest that the tensile strain, when measured using a non-standard method and miniature dog-bone tensile specimens, is likely to contain significant errors. In this study, by implementing a standard strain measurement and tensile specimens with geometries that meet the ASTM requirements, we report yield strength and ductility combinations of 370 MPa 9 % (Bc 2 passes) and 370 MPa 16 % (Bc 16 passes) in the ultrafine grained copper. The higher ductility of the ultrafine grained copper processed by route Bc 16 passes was rationalized on the basis of several factors including the presence of equiaxed grains, lower dislocation density and higher fraction of high-angle grain boundaries (which result in larger strain rate sensitivity and strain hardening).