O'Donovan, John T.Grant, Cynthia A.Blackshaw, Robert E.Harker, K. Neil...
12页
查看更多>>摘要：High costs of fertilizer in western Canada have generated interest in alternative N sources. Legumes produce N through fixation, and may increase soil residual and mineralizable N, thus reducing the need for fertilizer N in subsequent crops. Hybrid canola (Brassica napus L.) has a high N requirement for optimum yield, but knowledge of rotational effects of legumes on canola is limited. The objective was to determine the effects of legume and non-legume preceding crops on yield and quality of canola grown the following year and malting barley (Hordeum vulgare L.) grown after canola. Field pea (Pisum sativum L.), lentil (Lens culinaris Medik.), faba bean (Vicia faba L.), canola, and wheat (Triticum aestivum L.) harvested for grain, and faba bean grown as a green manure were direct-seeded at seven locations in 2009. Canola was seeded in 2010 and barley in 2011, with fertilizer N applied at 0, 30, 60, 90, and 120 kg ha(-1). On average, all legumes, except faba bean for seed, produced higher canola and barley yields than when wheat was the preceding crop. Faba bean green manure produced the highest yields, while canola on canola produced the lowest canola yield. The legumes had little negative effect on canola oil or barley protein concentration. Yields of both crops increased with increasing N rate, but canola oil concentration decreased, and barley protein increased. The results indicate that growing legumes for seed before hybrid canola can improve canola and subsequent barley yield without negatively affecting canola oil or malting barley protein.
查看更多>>摘要：Little is known how to optimize N supply of cereal components in an intercropping system that considers biological nitrogen fixation (BNF) from soybean [Glycine max (L.) Merr.]. A 2-yr field experiment was conducted to study the compatibility of soybean-cereals intercropping as influenced by varying N levels to intercropped cereals as per recommended dose of nitrogen (RDN) for respective cereals. Soybean was grown as the main crop with 100% plant population and cereals were intercropped at 2:1 ratio in additive series (without sacrificing main crop population). While the yield of intercropped maize (Zea mays L.) significantly increased up to 100% RDN, the yield of intercropped sorghum [Sorghum bicolor (L.) Moench.] and pearl millet [Pennisetum typhoides (Burm.f.) Stapf & C.E. Hubb.] increased only up to 75 and 50% RDN, respectively. The soybean yield reduced by 33.6, 37.9 and 58.3% due to intercropping with maize, sorghum and pearl millet, respectively. The soybean equivalent yield, net return, benefit cost ratio and monetary advantage index were maximum in soybean+maize intercropping provided with 100% RDN to maize. Land equivalent ratio, relative crowding coefficient and intercropping advantage were the greatest with soybean+maize intercropping proving that there was an advantage of intercropping with maize. The aggressivity and competitive ratio were higher for pearl millet and sorghum as compared to maize indicating that pearl millet and sorghum were more competitive to soybean than maize. The study indicated the possibility to reduce N fertilizer requirement by 25 and 50% in case of sorghum and pearl millet as intercrop with soybean, respectively.
Chen, PengyinCarter, Thomas E.Devi, Jyostna MuraSinclair, Thomas R....
8页
查看更多>>摘要：Breeding efforts in soybean [Glycine max (L.) Merr.] have addressed the challenge of water-limited yields by incorporating parental stocks which exhibit drought-tolerant traits. Multiple cycles of empirical selection for improved yielding ability in water-deficient field environments have produced new generations of adapted breeding lines. However, the impact of this selection process on specific putative drought-tolerant traits is unknown. The objective of this study was to determine if breeders' selection of 10 elite lines for high seed yield under dry conditions is associated with the presence of physiological expression of three putative drought-tolerant traits: (i) limited transpiration rate under high vapor pressure deficit (VPD), (ii) early decrease in transpiration rate with soil drying, and (iii) drought-tolerant N-2 fixation. Greenhouse experiments were undertaken to characterize each genotypes for their phenotype of each of these three traits. Unlike most soybean cultivars, 9 of the 10 elite lines expressed a limited transpiration rate under elevated VPD. The VPD at which transpiration rate became limited was 1.9 kPa or less. There was no difference among genotypes in the threshold for decline in transpiration rate with soil drying, although all genotypes expressed high thresholds indicating an ability to conserve soil water. All lines expressed drought tolerance in their N-2 fixation rates, which was superior to that commonly observed in soybean. This study demonstrated that mating of parents that expressed a drought trait and multiple rounds of progeny selection based on improved yield under water-limited conditions resulted in the elite lines expressing improved drought traits.
Gaspar, Adam P.Marburger, David A.Mourtzinis, SpyridonConley, Shawn P....
8页
查看更多>>摘要：Soybean [Glycine max (L.) Merr.] seed treatment adoption has increased dramatically over the past decade in addition to the number of pesticide components within commercially available seed treatments. The study objectives were to evaluate the effects of multiple seed treatments and their individual pesticide components (fungicide, insecticide, and/or nematicide) on soybean plant stand and seed yield across diverse environments. Trials were conducted at 10 Wisconsin locations during the 2011 to 2013 growing seasons. Soybean seed treatments containing fungicide + insecticide + nematicide increased plant stands over the untreated control (UTC), fungicide only, and fungicide + insecticide seed treatments by an average of 10, 9, and 5.5%, respectively. During 2013, yield was increased by the fungicide only seed treatment pyraclostrobin + metalaxyl + fluxapyroxad; however, across all environments, no consistent yield increase was shown for fungicide only seed treatments. Fungicide + insecticide seed treatments increased yield over fungicide only seed treatments by 55 and 76 kg ha(-1) during 2011-2012 and 2013, respectively, and were similar to fungicide + insecticide + nematicide seed treatments. However, fungicide + insecticide and fungicide + insecticide + nematicide seed treatments only increased yield over the UTC in 2013. These results suggest that though fungicide + insecticide and fungicide + insecticide + nematicide seed treatments consistently increased plant stand, yield increases were variable and contingent on unpredictable factors. Therefore, producers will need to weigh potential yield gains with biological (resistance management) and economic (return on investment [ROI] and risk mitigation) concerns before implementing seed treatment practices at the whole farm level.
Kaiser, Daniel E.Lamb, John A.Bloom, Paul R.Hernandez, Jose A....
12页
查看更多>>摘要：Iron deficiency chlorosis (IDC) is a serious management issue for soybean [Glycine max (L.) Merr.] grown on calcareous soils. Strip trials were established on calcareous Mollisols to study the effects of Fe-ethylene diamine-N, N'-bis (hydroxy phenyl) acetic acid (EDDHA) in-furrow (IF-Fe) and of an oat (Avena sativa L.) companion crop on two soybean varieties either tolerant or susceptible to IDC. The severity of IDC varied from low to severe within sites. The susceptible variety produced the highest yield in the absence of IDC. In-furrow Fe increased the yield of a variety susceptible to IDC under moderate to severe IDC. The oat companion crop increased yield consistently for the susceptible variety under severe IDC and sometimes reduced yield when oat grew beyond 25 cm in height. The tolerant variety without IDC management produced yields similar to those of the susceptible variety with IF-Fe or an oat companion crop. Oat reduced trifoliate nitrate N and Fe concentration regardless of IDC severity. Trifoliate Fe concentration lowered with IF-Fe, but only when oat was not planted. Grain protein and oil concentration were affected by variety, but were not affected by IDC management. Soil test factors such as soil organic matter (SOM), pH, electrical conductivity (EC), or diethylene triamine phentaacetic acid Fe (Fe-DTPA) were poor predictors of the severity of IDC. Variety selection is the most important strategy for lessening the severity of IDC. In-furrow application of Fe-EDDHA provides a solution for mitigating moderate to severe IDC and provides less risk than an oat companion crop.
查看更多>>摘要：Phosphorus fertilizer is regulated in many states for use on home lawns. Such regulation should be species-based. The objective of this study was to compare establishment of different cool-season turfgrasses at various levels of Olsen P in a calcareous soil. Shoot density and biomass of 'Midnight' and 'Fighter' Kentucky bluegrass (Poa pratensis L.), 'Emerald' and 'Accent II' perennial ryegrass (Lolium perenne L.), 'Arid III' and 'Alamo' tall fescue (Festuca arundinacea Schreb.), 'T1' and 'Seaside II' creeping bentgrass (Agrostis stolonifera L.), and 'Maxima' and 'Boreal' red fescue (Festuca rubra L.) were evaluated with P applied at 0, 3.75, 11.25, 33.75, 56.25, and 75 kg ha(-1) in 2012 and 2013 on soils with an initial Olsen P of 10.7 and 10.3 mg kg(-1). Based on the number of days required to reach 50% ground cover (D50), Kentucky bluegrass had a critical soil Olsen P of 15 mg kg(-1), which meant P application at 11.25 kg ha(-1) in 2012 and no application in 2013. Creeping bentgrass required a soil Olsen P of 15 to 20 mg kg(-1) for the same purpose. If evaluated by shoot biomass, the critical soil Olsen P values were 16.5 to 22 mg kg(-1) for Kentucky bluegrass, 20 to 22.5 mg kg(-1) for creeping bentgrass, 19 to 22 mg kg(-1) for tall fescue, and 22 to 25 mg kg(-1) for perennial ryegrass. Critical soil P levels for D50 vary within a species and should be considered when making recommendations for P application.
Nalley, Lawton L.Dixon, Bruce L.Brye, KrisRogers, Christopher W....
12页
查看更多>>摘要：Previous research has demonstrated that rice (Oryza sativa L.) production poses two large, global environmental concerns: rice uses 25% of the global freshwater supply and generates considerable greenhouse gas (GHG) emissions. The shorter vegetative stage of hybrids compared with conventional (inbred) cultivars may provide two environmental improvements: reduced water consumption and decreased CH4 emissions. This study evaluated the effect of cultivar type on water-use efficiency and net GHG emissions. Water usage and GHG emissions on a per-hectare and per-kilogram-of-grain basis were estimated for hybrid and conventional rice cultivars with a new methodology using seven consecutive years of cultivar-trial data. Because GHG emissions have not been observed directly in cultivar trial experiments, a method of synthesizing GHG emission levels was designed. This method utilizes results from in-field chamber experiments from flooding to after harvest plus emergence and 50% heading dates. Hybrid rice cultivars were estimated to be 23.22% more efficient than conventional cultivars in reducing GHG emissions and 33.47% more efficient in reducing water required per unit grain yield produced. Unlike other approaches to lowering GHG emissions and water usage, substituting hybrids for conventional cultivars appears to be a viable option with low producer transaction costs as opposed to such alternatives as alternate wet-dry flooding, building on-farm reservoirs, etc.. The methodology used produced results that are consistent with the present knowledge of the physiological and cultural practice differences between conventional and hybrid rice production. The GHG synthesizing methodology could be directly applied to other states' historic cultivar trial data.
Jahanzad, E.Sadeghpour, A.Hosseini, M. B.Barker, A. V....
8页
查看更多>>摘要：Shortage of irrigation water in arid and semi-arid regions has forced forage producers to look for drought-tolerant species for silage production. To evaluate silage yield and nutritive value of pearl millet (Pennisetum glaucum L.)-soybean [Glycine max (L.) Merr.] intercrops as influenced by intercropping ratios and N rates, a 2-yr field experiment was conducted using split-plot lay out on a randomized complete block (RCB) design. Main plots consisted of 0, 37, and 74 kg N ha(-1) (N-0, N-37, and N-74, respectively) and intercropping ratios of millet and soybean (50% M:50% S; 60% M:40% S; and 40% M:60% S) along with monocultures were assigned to subplots. Increasing N resulted in 9.9 and 17.6% silage yield increase at N-37 and N-74 levels compared with N-0. Nitrogen also increased organic acids and ammonia nitrogen (NH3-N) content. Silage pH was lower (4.23) where no fertilizer was applied compared with the fertilized plants (4.33). The highest crude protein (CP) content (170 g kg(-1) dry matter [DM]) and dry mass (248 g DM kg(-1) fresh weight) was at the N74. Silage produced by the millet-soybean mixtures was well fermented indicated by low pH and high lactic acid. Also, intercropping ratios had less acid detergent fiber (ADF) and neutral detergent fiber (NDF) than monocultures. Although all of the intercropping ratios had characteristics of well-fermented silage, a mixture of 60% millet and 40% soybean could be superior because of higher silage yield and CP.
Johnson, Jerry J.McMaster, Gregory S.Vigil, Merle F.Sauer, Sally M....
12页
查看更多>>摘要：Grain sorghum [Sorghum bicolor (L.) Moench] is an important dryland crop in southeastern Colorado, but expansion into northeastern Colorado is thought to be limited due to the shorter growing season. The study examined whether sorghum production could be expanded into northeastern Colorado. A 2-yr study in northeastern Colorado at Akron (2010, 2011), Fort Collins (2011), and Stratton (2010) investigated row orientation, seeding rate, and row spacing effects for three hybrids within early to medium-early maturity classes on the time to physiological maturity and grain yield. All treatments reached physiological maturity in the four trial environments. Hybrid selection and seeding rate significantly impacted the thermal time to reach physiological maturity. The medium-early hybrid (5745) matured significantly later than the early maturity hybrids (88P68 and DKS29-28). The seeding rate of 20 seeds m(-2) matured significantly earlier than 11 seeds m(-2), which matured much earlier than 3 seeds m(-2). Row orientation and row spacing did not influence maturity. Yields were generally acceptable across all environments, hybrids, and agronomic treatments, and average yields among environments ranged from 1690 to 4845 kg ha(-1). Probabilities of the hybrids reaching maturity were high at Akron and Stratton (at least 62 and 86%, respectively, for the latest simulated planting date), but low for Fort Collins (highest of 75% for the earliest simulated planting date). Grain sorghum can successfully be grown in northeast Colorado, especially if planting early maturity hybrids using 0.76 m row spacing at a seeding rate close to 11 seeds m(-2).
查看更多>>摘要：Dry season (boro) rice (Oryza sativa L.) is an important crop in coastal areas of India, but little attention has been devoted to optimize crop and resource management for this important ecosystem. Four methods of crop establishment were tested on puddled soil: direct sowing of pre-germinated seeds with drum seeder, transplanting 12- and 18-d-old seedlings and conventional transplanting of 25-d-old seedlings (farmers' practice). Three nutrient treatments were also evaluated: recommended dose of fertilizers (RDF; 120-20-0 kg N-P2O5-K2O ha(-1)), RDF + Azolla (2 t ha(-1)) and RDF + 5 t ha(-1) of farmyard manure (FYM). Azolla is a N-rich freshwater fern that can be produced in ponds and ditches. Drum-seeding increased plant height, tiller number, leaf area index, and net photosynthetic rate. Grain and straw yields (4.85 and 8.13 t ha(-1), respectively) were significantly higher with drum seeding than with transplanting. Grain yield was 34, 37, and 38% higher compared with 12-, 18-, and 25-d-old transplanted seedlings, respectively. Seedling age at transplanting did not affect grain yield, but the benefit/cost ratio (BCR) (1.94) was higher with drum seeding than with transplanting. Grain and straw yields under RDF + FYM were, respectively, 24 and 21% higher than RDF, but were only 11 and 12% higher compared with RDF + Azolla treatment. Integrated management practices combining a salt-tolerant variety (Canning 7) with drum seeding and nutrient management that include chemical and organic fertilizers could enhance the productivity of boro rice in saline coastal soils.
NSTL
Amer Soc Agronomy
Wiley