• Authors:
    • Nyakatawa, E. Z.
    • Reddy, S. S.
    • Reddy, C. K.
  • Source: International Journal of Agriculture & Biology
  • Volume: 14
  • Issue: 1
  • Year: 2012
  • Summary: Nitrogen uptake pattern by cotton (Gossypium hirsutum L.) at different growth stages in response to long-term application of poultry litter (PL) in a no-till system (NT) was studied on a silt loam soil in 2009. The study was done in plots that were established in 1996 at TVREC, Belle Mina, AL, USA. Treatments included were three tillage [conventional tillage (CT), mulch-tillage (MT), and no-tillage (NT)] two cropping systems tot ton-lye (C-R; cotton in summer & cereal rye cover crop in winter), and cotton-fallow (C-F; cotton in summer & fallow in winter)] and two sources of nitrogen [PL at 100 and 200 kg N ha(-1) and ammonium nitrate (AN) at 100 kg N ha(-1)] Out of all treatment combinations only 11 important treatments were selected and arranged in a randomized complete block design and replicated 4 times. Results in 2009, showed that NT system can supply equal quantity of nitrogen compared to CT at all growth stages. No-tillage recorded similar growth, yield and total nitrogen uptake compared to CT. Application of PL at 100 kg N ha(-1) showed significantly superior plant growth compared to AN at early growth stage, but the differences disappeared as the plant growth progressed. Similar yields and nitrogen uptake were observed with application of either PL or AN at 100 kg N ha(-1). Application of a double rate of PL (200 kg N ha(-1)) resulted in significantly higher nitrogen uptake compared to that of PL or AN at 100 kg N ha(-1), but a significant yield advantage was not observed with this higher rate. Of the total nitrogen extracted by cotton at maturity, 50% uptake was completed by early flowering stage and 97% was completed by boll development stage. At maturity, the majority of nitrogen (52%) was partitioned into seeds, while the rest was distributed into leaves (16%), stems (18%) and reproductive parts (14%). winter rye cover crop did not influence nitrogen uptake. (C) 2012 Friends Science Publishers
  • Authors:
    • Ge, Y.
    • Morgan, C. L. S.
    • Sarkhot, D. V.
    • Grunwald, S.
  • Source: Biomass and Bioenergy
  • Volume: 41
  • Year: 2012
  • Summary: Understanding and quantifying the impact of bioenergy crops on soil carbon (C) storage is an essential component of crop management. Our objectives were to (i) compare total (TC), organic (OC), and inorganic carbon (IC) storage under Cynodon dactylon (L.) Pers and the energy crop Arundo donax L. along the soil profile, and (ii) determine the effect of these crops on available soil C (measured as hot water extractable C, HC) as an indirect indicator of soil C changes. The study site was within the Rio Grande floodplain in Quemado, Texas covered by A. donax and C. dactylon. Soil samples were taken from five soil depths: 0-10, 10-20, 20-30, 30-40, and 40-50 cm at 125 locations in a 34.5 ha field; TC, IC, and HC were measured and OC was derived. In all four C pools, soils under A. donax had higher C content (volumetric C or Cv, kg m -2) than soils under C. dactylon, except for IC at the top two depths. Larger soil C storage under A. donax as compared to C. dactylon was consistent throughout the profile. The effect was most pronounced for volumetric HC content (HCv) with 43% higher amount under A. donax than C. dactylon at 0-10 cm depth. In areas, where A. donax is considered an invasive species, the available biomass can be used for bioenergy production and the higher soil carbon under A. donax can provide additional economic return in a C economy.
  • Authors:
    • Robertson, G.
    • Tausig, J.
    • Hamilton, S.
    • Basso, B.
    • Syswerda, S.
  • Source: Agricultural Ecosystems and Environment
  • Volume: 149
  • Year: 2012
  • Summary: Nitrate (NO 3-) loss from intensively farmed cropland is a long-standing, recalcitrant environmental problem that contributes to surface and groundwater pollution and coastal zone hypoxia. Here nitrate leaching losses are reported from nine replicated cropped and unmanaged ecosystems in southwest Michigan, USA. Ecosystems include four annual corn-soybean-winter wheat rotations under conventional, no-till, reduced-input, and organic/biologically-based management, two perennial cropping systems that include alfalfa and hybrid poplar trees, and three unmanaged successional communities including an early successional community analogous to a cellulosic biofuel system as well as a mature deciduous forest. The organic, alfalfa, and unmanaged systems received no synthetic, manure, or compost nitrogen. Measured nitrate concentrations were combined with modeled soil water drainage to provide estimates of nitrate lost by leaching over 11 years. Among annual crops, average nitrate losses differed significantly ( pno-till (41.33.0)>reduced-input (24.30.7) > organic (19.00.8) management. Among perennial and unmanaged ecosystems, nitrate loss followed the pattern alfalfa (12.81.8 kg N ha -1 yr -1)=deciduous forest (11.04.2) >> early successional (1.10.4)=mid-successional (0.90.4) > poplar (<0.010.007 kg N ha -1 yr -1) systems. Findings suggest that nitrate loss in annual row crops could be significantly mitigated by the adoption of no-till, cover crops, and greater reliance on biologically based inputs, and in biofuel systems by the production of cellulosic rather than grain-based feedstocks.
  • Authors:
    • Ugarte, D. G. de la T.
    • English, B. C.
    • Roberts, R. K.
    • Larson, J. A.
    • Toliver, D. K.
    • West, T. O.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 2
  • Year: 2012
  • Summary: This research evaluated differences in yields and associated downside risk from using no-till and tillage practices. Yields from 442 paired tillage experiments across the United States were evaluated with respect to six crops and environmental factors including geographic location, annual precipitation, soil texture, and time since conversion from tillage to no-till. Results indicated that mean yields for sorghum [ Sorghum bicolor (L.) Moench] and wheat ( Triticum aestivum L.) with no-till were greater than with tillage. In addition, no-till tended to produce similar or greater mean yields than tillage for crops grown on loamy soils in the Southern Seaboard and Mississippi Portal regions. A warmer and more humid climate and warmer soils in these regions relative to the Heartland, Basin and Range, and Fruitful Rim regions appear to favor no-till on loamy soils. With the exception of corn ( Zea mays L.) and cotton ( Gossypium hirsutum L.) in the Southern Seaboard region, no-till performed poorly on sandy soils. Crops grown in the Southern Seaboard were less likely to have lower no-till yields than tillage yields on loamy soils and thus had lower downside yield risk than other farm resource regions. Consistent with mean yield results, soybean [ Glycine max (L.) Merr.] and wheat grown on sandy soils in the Southern Seaboard region using no-till had larger downside yield risks than when produced with no-till on loamy soils. The key findings of this study support the hypothesis that soil and climate factors impact no-till yields relative to tillage yields and may be an important factor influencing risk and expected return and the adoption of the practice by farmers.
  • Authors:
    • Alldredge, J. R.
    • Long, D. S.
    • Young, F. L.
  • Source: Crop Management
  • Issue: March
  • Year: 2012
  • Summary: Growers are becoming interested in producing canola ( Brassica napus or B. rapa) in the dryland, wheat-fallow region of the Pacific Northwest. Currently, agronomic research for spring canola in this region has not been initiated. This study evaluated the effect of no-till planting methods on stand establishment, crop yield, and seed oil quantity of spring canola in Washington and Oregon in 2009 and 2010. The treatments included: double disk opener; broadcast; broadcast plus rolled; Kile opener; Cross-Slot opener; and hoe opener (at Washington only). In this study, canola establishment was generally greatest with the double disk opener and least in the broadcast or broadcast plus rolled treatments at all four site-years. Yield was least in the broadcast treatment and rolling broadcast seed increased yield only 50% of the time. In three out of four site-years, canola planted with the various no-till openers yielded higher than broadcast seed. The adoption of spring canola in the wheat-fallow region of the Pacific Northwest would improve pest management strategies, diversify markets, and increase sustainability.
  • Authors:
    • Everts, K. L.
    • Zhou, X. G.
  • Source: Plant Disease
  • Volume: 96
  • Issue: 3
  • Year: 2012
  • Summary: Multiple applications of fungicides are used to manage anthracnose caused by Colletotrichum orbiculare and gummy stem blight caused by Didymella bryoniae, the two most common and destructive diseases on watermelon ( Citrullus lanatus) in the mid-Atlantic region of the United States. To develop a sustainable, nonchemical management option, a split-plot experiment was conducted over 3 years to evaluate the effects of a no-till hairy vetch ( Vicia villosa) cover crop on disease severity, plant growth, and fruit yield compared with two conventional bedding systems and fungicide application. The main plots were bedding strategies consisting of bare ground, polyethylene covering, or a hairy vetch cover crop that was planted in the fall, killed the following spring, and left on the soil surface as an organic mulch. The subplots were a nonfungicide control or a weekly application of a standard fungicide program. Hairy vetch mulch provided greater than a 65% reduction in the area under the disease progress curves of anthracnose and gummy stem blight and greater than an 88% decrease in diseased fruit compared with bare ground or polyethylene mulch. The reductions were comparable with those achieved by fungicide applications. Watermelon vine lengths in plots with hairy vetch were similar to or greater than those in plots with polyethylene or bare ground that were treated with fungicides. Marketable fruit in plots with hairy vetch was higher compared with bare ground in 2 of 3 years and was similar to that in plots treated with fungicides in all 3 years. Addition of fungicide application to hairy vetch treatment further reduced anthracnose in 1 year and gummy stem blight in 2 years but did not significantly increase fruit yield in all 3 years. This is the first demonstration that a no-till hairy vetch production system can reduce anthracnose and gummy stem blight on watermelon and that the production system has the potential to mitigate damage caused by these diseases.
  • Authors:
    • Bryant, R. B.
    • Schmidt, J. P.
    • Zhu, Q.
  • Source: Journal of Hydrology
  • Volume: 414-415
  • Year: 2012
  • Summary: Non-point nitrogen (N) and phosphorus (P) pollution from agriculture has increasingly received more public attention. In this study. NO3-N, dissolved P (DP) and particulate P (PP) concentrations and loads were investigated for four sub-basins (labeled 1-4 going up the watershed) within a mixed land use watershed (39.5 ha) in the Appalachian Valley and Ridge Physiographic Province. The hot moments of NO3-N concentration and load occurred in base flow and during the non-growing season. Great and temporally variable DP and PP concentrations were observed in storm flow. The hot moments of DP concentration and load were in storm flow from May to December and from September to Nov, respectively, while the hot moments of PP concentration and load were in storm flow from January to June. The NO3-N, DP, and PP loads were compared for all four sub-basins on a loss per length of stream reach basis to determine the hot spots and their corresponding losses. The hot spots and hot moments of NO3-N loads were in Sub-basins 1 and 4 during the non-growing season base flow period and Sub-basin 2 during the post-growing season base flow period (>110 g m(-1) mo(-1)). The hot spots of DP loads were also in Subbasins 1 and 4, but during the growing and post-growing season storm flow period (>1.4 g m(-1) mo(-1)). In contrast, the hot spots and hot moments of PP load were in Sub-basin 3 during the pre-growing and growing season storm flow, as much as 13.4 and 14.1 g m(-1) mo(-1), respectively. Controlling factors of nutrient export were discussed in this study, including season, hydrology (base flow, storm flow, surface and subsurface runoff), and land use. Although different hot moments and hot spots within the watershed were identified for NO3-N, DP, and PP losses, the implementation of a couple of management practices (cover crops and no-till) might be sufficient to effectively reduce nutrient losses from this and similar Valley and Ridge watersheds.
  • Authors:
    • Handoo, Z. A.
    • Cram, M. M.
    • Fraedrich, S. W.
    • Zarnoch, S. J.
  • Source: Nematology
  • Volume: 14
  • Issue: 4
  • Year: 2012
  • Summary: Tylenchorhynchus ewingi, a stunt nematode, causes severe injury to slash pine seedlings and has been recently associated with stunting and chlorosis of loblolly pine seedlings at some forest tree nurseries in southern USA. Experiments confirmed that loblolly pine is a host for T. ewingi, and that the nematode is capable of causing severe damage to root systems. Initial population densities as low as 60 nematodes (100 cm 3 soil) -1 were sufficient to damage the root systems of loblolly pine seedlings. Populations of T. ewingi increased on pine from two- to 16-fold, depending on the initial population density. Evaluations of various cover crops used in southern forest tree nurseries indicated that legumes, rye and several varieties of sorghum were excellent hosts for T. ewingi. Other small grains such as ryegrass, oats and wheat were poorer hosts. A cultivar of pearl millet was a non-host for T. ewingi, and a cultivar of brown top millet appeared to be either a very poor host or a non-host. Nurseries that have seedling production losses caused by T. ewingi should consider rotating with non-host cover crops such as pearl millet or leaving fields fallow as part of their pest management programme.
  • Authors:
    • [Anonymous]
  • Source: Applied Engineering in Agriculture
  • Volume: 28
  • Issue: 3
  • Year: 2012
  • Summary: This special section includes four papers providing information on the: current status of microsprinkler irrigation in the USA; cotton response to crop row offset and orientation to subsurface drip irrigation laterals; integrated decision support, sensor networks, and adaptive control for wireless site-specific sprinkler irrigation; and a review of mechanical move sprinkler irrigation control and automation technologies.
  • Authors:
    • Collins, H.
    • Moore, A.
    • Alva, A.
  • Source: Journal of Crop Improvement
  • Volume: 26
  • Issue: 2
  • Year: 2012
  • Summary: Potato ( Solanum tuberosum L.) tuber yield and quality are impacted by irrigation and nitrogen (N) management. This study was conducted in the Pacific Northwest (PNW) region of United States to evaluate the effects of deficit irrigation (DI) and rates of pre-plant and in-season N applications on Ranger Russet and Umatilla Russet cultivars. In 2004, with Ranger Russet only, DI with 20% lower total irrigation for the entire growing period resulted in 28% tuber yield reduction compared to that of plants irrigated to replenishment full evapotranspiration (ET), i.e., full irrigation (FI). A subsequent study in 2006 and 2007 with DI (14% to 17% deficit) resulted in tuber yield reduction of 7% to 10% in both cultivars compared to full ET irrigation. Yield reduction in DI was generally attributed to reduction in large weight tubers, >0.227 kg/tuber, in both cultivars across three years. Petiole NO 3-N concentrations were greater in plants grown under DI as compared to those of plants in full ET irrigation across all years and cultivars, particularly during tuber maturation stage. This is an important consideration as increased N availability during the late growing season adversely affects tuber quality. Petiole NO 3-N concentrations increased with increased in-season N rates. In 2007, 112 kg.ha -1 in-season N resulted in petiole NO 3-N concentrations below desirable concentrations across most of the growing season in both cultivars. This, in turn, contributed to a significant reduction in tuber yield as compared to the 224 kg.ha -1 in-season N rate. Continuous DI with 14% to 20% reduction in water as compared to irrigation to replenish full ET, begun three to four weeks after seedling emergence, had significant negative effects on tuber yields of both cultivars in high-production irrigated growing conditions. Application of N up to 112 kg ha -1 as pre-plant soil applied plus 224 kg ha -1 of in-season fertigation in five applications at two-week intervals beginning four weeks after seedling emergence appears to be adequate to support high yields of high-quality tubers.