• Authors:
    • Rickman, R. W.
    • Liang, Y.
    • Albrecht, S. L.
    • Machado, S.
    • Kang, S.
    • Gollany, H. T.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 1
  • Year: 2011
  • Summary: Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model and (ii) to predict the potential of no-tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to 2- or 3-yr crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned, or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1-19 degrees C), precipitation (402-973 mm), and SOC (5.89-33.58 g SOC kg(-1)) at the LTE sites were significantly related (r(2) = 0.94, n = 186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks.
  • Authors:
    • Jantalia, C. P.
    • Halvorson, A. D.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 5
  • Year: 2011
  • Summary: Converting to no-till (NT) production can affect N requirements for optimizing corn ( Zea mays L.) yields while enhancing soil organic carbon (SOC) and N levels. Nitrogen fertilization impacts on irrigated, NT continuous-corn grain, stalk, cob, and stover yields, stover C and N uptake, and C/N ratios were evaluated for 11 yr on a clay loam soil. Changes in SOC and total soil nitrogen (TSN) were also monitored. Grain, stalk, cob, and stover yields increased with increasing N rate, as did N and C uptake. The C/N ratio of stalk residue declined with increasing N rate, but cob C/N ratio was not affected, with an average stover C/N ratio of 68 at the highest N rate. Nitrogen fertilization increased SOC and TSN levels with average SOC and TSN mass rate gains with N application of 0.388, 0.321, and 0.160 Mg SOC ha -1 yr -1 and 0.063, 0.091, and 0.140 Mg TSN ha -1 yr -1 in the 0- to 7.6-, 0- to 15.2-, and 0- to 30.4-cm soil depths, respectively. The SOC and TSN mass rate changes were lower without N application. Increases in TSN appeared to be more rapid than SOC, resulting in a decline in the soil C/N ratio with time. Under irrigated, NT continuous corn production, N fertilization optimized grain and residue yields, with the enhanced benefit of increased SOC and TSN levels in the semiarid central Great Plains. Removal of cobs or partial stover residue as a cellulosic feedstock for ethanol production appears possible without negative effects on soil quality under irrigated, NT corn production.
  • Authors:
    • Beres, B. L.
    • Carcamo, H. A.
    • Dosdall, L. M.
    • Yang, R. C.
    • Evenden, M. L.
    • Spaner, D. M.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 6
  • Year: 2011
  • Summary: Most semiarid regions of the northern Great Plains are prone to wheat stem sawfly (Hymenoptera: Cephidae, Cephus cinctus Norton) attack. As an alternative to the wheat ( Triticum aestivum L.)-fallow system, our objective was to determine if continuous cropping infested wheat stubble would inhibit wheat stem sawfly (WSS) emergence. Adult sawfly emergence from undisturbed stubble was compared to stubble harrowed with heavy tine or rotary drum harrows before recropping. Adult emergence from a control of "no recropping" was compared to direct seeding infested stubble with (i) air drills configured with knife-type openers spaced 23 or 30 cm apart, (ii) an air drill configured with high disturbance shovel-type sweep openers, and (iii) a low disturbance air drill equipped with disc openers. Pre-seed heavy tine harrowing reduced adult sawfly emergence but usually required a high tension setting. No-till planting into infested spring wheat stubble also lowered WSS emergence compared to leaving the field fallow. A system of heavy tine harrows and an air drill equipped with knife openers spaced 30 cm apart reduced WSS adult emergence in spring by 50 to 70%. Grain yield was optimized in spring wheat with air drills equipped with narrow knife openers; in winter wheat optimal yield was obtained with the low disturbance disc drill configurations. Our results indicate incremental benefits from continuous cropping rather than fallowing fields infested with WSS, which is a sustainable alternative to conventional tillage. A systems approach is recommended that integrates these practices with diversified nonhost crop phases and resistant cultivars.
  • Authors:
    • Lenssen, A. W.
    • Sainju, U. M.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 2
  • Year: 2011
  • Summary: Forages grown in rotation with or without cereals to sustain dryland soil water content and crop production may influence N dynamics. We evaluated the effect of alfalfa ( Medicago sativa L.) and durum ( Triticum turgidum L.)-annual forage cropping sequences on above-(stems+leaves) and belowground (roots) biomass N, dryland soil total N (STN), particulate organic N (PON), microbial biomass N (MBN), potential N mineralization (PNM), NH 4-N, and NO 3-N contents at the 0- to 120-cm depth in northeastern Montana from 2002 to 2005. Cropping sequences were continuous alfalfa (CA), durum-barley ( Hordeum vulgare L.) hay (D-B), durum-foxtail millet ( Setaria italica L.) hay (D-M), durum-Austrian winter pea ( Pisum sativum L.)/barley mixture hay (D-P/B), and durum-fallow (D-F). From 2002 to 2005, total above- and belowground biomass N was 20 to 97 kg N ha -1 greater under CA than other treatments. In 2005, STN, PON, and PNM were 7 to 490 kg N ha -1 greater under CA than D-M, D-B, and D-P/B at 0 to 30 cm but varied by treatment at other depths. In contrast, MBN at 0 to 15 cm and NH 4-N content at 30 to 90 cm were 23 to 37 kg N ha -1 greater under D-B than D-M and D-F. The NO 3-N content at 0 to 120 cm was 65 to 107 kg N ha -1 greater under D-P/B than other treatments. Even though haying removed a greater amount of N, alfalfa increased surface soil N storage and mineralization and reduced the potential for N leaching compared with durum-annual forages, probably due to increased root growth or N 2 fixation. Durum-pea/barley hay, however, increased N mineralization and availability in subsoil layers, probably due to greater root N concentration or downward movement of water-soluble N.
  • Authors:
    • Ryan, J.
    • Yahyaoui, A.
    • Ahmed, S.
    • Pala, M.
  • Source: Arab Journal of Plant Protection
  • Volume: 29
  • Issue: 2
  • Year: 2011
  • Summary: Yield declines commonly observed under cereal monoculture are invariably attributed to disease buildup as well as nutrient and moisture depletions. While many long-term trials in the West Asia and North Africa region, especially in northern Syria rainfed cereal production belt, have assessed various cropping alternatives in comparison with fallow and continuous cereal cropping, few trials have involved measurement of fungal diseases. This paper reports observations made on the incidence of common root rot ( Cochliobolus sativus) from long-term trials at the International Center for Agriculture Research in the Dry Areas involving wheat and barley. With both cereals, crop rotation with legumes was shown to reduce the incidence of root rot. The results clearly indicated the need for a more comprehensive phytopathological assessment of the implications of continuous cereal cropping, especially considering the effects of residue management and nitrogen fertilization.
  • Authors:
    • Adetunji, M.
    • Makinde, E.
    • Akande, M.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 9
  • Year: 2011
  • Summary: Field trials were conducted at the Institute of Agricultural Research and Training Ibadan in 2000 and 2001 cropping seasons to evaluate the efficiency of some phosphorus (P) sources, rates, and frequency of application on grain yields of maize and cowpea grown sequentially. The experiment was laid out in a split-split plot arrangement using randomized complete block design, with three replications. The main plot was frequency of fertilizer application (seasonal and annual). Source of P [single superphosphate (SSP: 18% P 2O 5)]; Ogun rock phosphate (OPR: 20.21% P 2O 5), and crystallizer super (CS: 31.4% P 2O 5) constituted the subplots. The P rates (0, 20, 40, and 60 kg P ha -1) were the sub-subplots. An early maize cropping followed by a late-season cowpea was the sequential cropping, while an early maize followed by a late-season maize was the continuous cropping. The croppings were repeated the second year. Frequency of P application and source of P were significantly different while rates of application were not. Maize and cowpea grain yields from the control treatment were significantly less than yields from P-treated plots. Maize grain yields were slightly greater in plots alternated with cowpea, compared to continuous maize. Relative agronomic efficiency (RAE) values of OPR and CS were 67% and 75%, respectively, in annual application and 140% and 134% in seasonal applications, respectively, in 2000. In 2001, the trend was almost similar to 2000 except that there was a decline in RAE values of cowpea. Each Naira invested in the annual application returned about Naira 3.12 while about Naira 2.13 was returned with the seasonal application (Naira 125.00 is the equivalent of USD$1.00). The OPR and CS can serve as alternatives to water-soluble sources such as SSP.
  • Authors:
    • Asadi, S.
    • Hokmalipour, S.
    • Sharifi, R.
    • Barmaki, M.
    • Kandi, M.
    • Darabad, G.
  • Source: Australian Journal of Basic and Applied Sciences
  • Volume: 5
  • Issue: 11
  • Year: 2011
  • Summary: In order to investigate the yield and yield components of mixed cropping of potato and safflower, as compared to those of the pure cropping, a study was carried out using factorial experiment with completely randomized block design and with three replications. This study was done in experiment field of University of Mohagheg Ardabili in the solar year 2010. The investigated treatments included potato pure cropping in the fixed density of 6 plants pre m 2, safflower pure cropping with the densities of 6, 12 and 18 plants per m 2, and the intercropping of potato (6 plants pre m 2 density) with safflower in the densities of 6,12 and 18 plants per m 2. The variance analysis of potato traits in both the intercropping and pure cropping indicated that, except from the number of stems pre m 2, other studied traits; including the number of tubes per plant, the tube weight per plant and the tube yield statistically differed meaningfully with each other. Moreover the results showed that all the studied traits including the number of receptacles pre plant, the number of seeds per receptacle, seed weight in the receptacle and seed yield, in terms of statistic figures differed with each other noticeably. In order to assess the efficiency of the intercropping, the indexes of LER and RVT were utilized. These indices proved that, almost in all cases, the intercropping is superior to the pure cropping. In this study the highest rates of LER and RVT (1/35 and 1/32 respectively), concerned the intercropping of safflower and potato with densities of 12 plants per m 2 and 6 plants per m 2 respectively.
  • Authors:
    • Li, Y.
    • Zu, Y.
    • Wu, B.
    • An, T.
    • Zhan, F.
    • Yang, J.
    • Fu, Z.
  • Source: Research of Environmental Sciences
  • Volume: 24
  • Issue: 11
  • Year: 2011
  • Summary: In order to explore the effects of different planting patterns for the effective control of farmland runoff contamination, loss of TN, TP, COD Cr and SS under different planting patterns were analyzed with field plot experiments. The results showed that the surface runoff, loss of TN, TP, COD Cr and SS under a mono-cropping system were higher than under a maize and vegetables intercropping system. The surface runoff, loss of TN, TP, COD Cr and SS could be reduced using a maize and vegetables intercropping system. The maize || cauliflower/potato intercropping pattern was the most effective. Comparing with cauliflower/potato mono-cropping system, its reduction percentages of surface runoff, TN, TP, COD Cr and SS were 79.59%, 86.87%, 84.23%, 91.41% and 82.46%, respectively.
  • Authors:
    • Matysiak, K.
    • Kaczmarek, S.
    • Kardasz, P.
  • Source: Biuletyn Instytutu Hodowli i Aklimatyzacji Roslin
  • Issue: 260/261
  • Year: 2011
  • Summary: Field experiments were carried out in 2005-2007 in the Experimental Station at Winna Gora, belonging to the Institute of Plant Protection - National Research Institute in Poznan. The aim of this study was to compare the efficacy of the herbicide mixtures tritosulfuron+dicamba (Mocarz 75 WG) in spring wheat variety Bryza, spring barley var. Antek and oat var. Cwa, sown separately and in cereal mixtures. Mocarz 75 WG herbicide was applied at a dose of 0.2 kg.ha -1 in the 3-5 leaf stage of cereals, using knapsack sprayer Gloria. Analysis of weed infestation of cereals were made by volume-weight assessment, twice during the growing season (3-4 weeks after herbicide application and 7-8 weeks after application). The efficacy of the herbicide in the cereal mixtures was compared with its effectiveness in the individual species. Analyses indicated that the barley-oat mixtures were the slightest and wheat-oat mixtures were the most infested by weeds. It was confirmed that a mixture of wheat and barley, wheat and oat and barley with oat reduced the influence of weed infestation. The higher efficacy of the mixture tritosulfuron+dicamba in cereal mixtures compared to the individual components was also indicated. Grain yields of cereals in mixtures with wheat as a component were significantly higher than in pure stands of wheat, while the yields of barley and oat mixture yielded higher than the two species sown alone.
  • Authors:
    • Ewusi-Mensah, N.
    • Logah, V.
    • Tetteh, F.
  • Source: Journal of Plant Sciences
  • Volume: 6
  • Issue: 4
  • Year: 2011
  • Summary: A field experiment to evaluate Soil Organic Carbon (SOC) and maize grain yield under different soil amendments and cropping systems was conducted in 2006 and 2007 at the Soil Research Institute, Kwadaso, Kumasi. The experiment was a split plot with three replications. The main plot factor (cropping systems) consisted of continuous maize, maize/soybean intercropping and maize cowpea rotation systems, the sub-plot (amendments) comprised of Poultry Manure (PM) at 4 t ha -1, poultry manure+chemical fertilizer (PM+CF) at 2 t ha -1 (PM)+45-30-30 kg ha -1 (NPK 15-15-15), Chemical Fertilizer (CF) at 90-60-60 kg ha -1 NPK 15-15-15 and a control (no amendment). Soil samples were taken at 21 and 84 days after amendment (DAA). Generally, PM+CF produced the highest range of SOC (1.14-1.37%). The least (0.98-1.28%) was recorded on the control plots. Plots amended with chemical fertilizer alone or in combination with poultry manure out-yielded the control in maize grain yield. Positive correlations between SOC at 84 DAA and maize grain yield were recorded in the major (r=0.70*) and minor (r=0.89**) rainy seasons of 2006 which established crop yield a function of SOC at harvest. Land equivalent ratios of sole maize (maize grown under continuous maize system) and maize intercropped with soybean were