• Authors:
    • Evanylo, G. K.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 21
  • Issue: 1-2
  • Year: 1990
  • Summary: Crop response to fertilizer nitrogen (N) is dependent upon tillage management. This study was conducted to determine how tillage rotation influences non‐irrigated crop growth, N uptake and yield. The effects of tillage rotation, N rate and N timing schedule on early season dry matter production and N uptake, ear leaf N concentration at silking, and yield of corn [Zea mays (L.) Pioneer 3378] were investigated at Painter, VA, on an Altavista loam (fine‐loamy, mixed, thermic Aquic Hapludult). In 1986, maximum yields achieved in the 6‐year continuous no till (NT) [5.82 Mg/ha] and first year no till (AT) [5.64 Mg/ha] were significantly greater than that of the 6‐year continuous conventional till (CT) [3.67 Mg/ha], but no yield differences were obtained in the drier 1987 season. A higher rate of N fertilizer was required to obtain maximum yield in the first year no till (168 kg N/ha) than in the NT (112 kg N/ha) during 1986. Early 1986 N uptake and growth response with and without N at planting increased in the order CT < AT = NT and AT < CT < NT, respectively, indicating greatest immobilization of soil N occurred in the newly established no till soil. Lack of differences in critical ear leaf N values developed for NT and CT in each year imply that plant norms developed for one tillage system may accurately assess N status of corn grown under different tillage practices.
  • Authors:
    • Raun, W. R.
    • Sander, D. H.
    • Olson, R. A.
  • Source: Agronomy Journal
  • Volume: 81
  • Issue: 2
  • Year: 1989
  • Authors:
    • Raun, W. R.
    • Sander, D. H.
    • Olson, R.A.
  • Source: Soil Science Society of America Journal
  • Volume: 51
  • Issue: 4
  • Year: 1987
  • Authors:
    • Power, J. F.
    • Doran, J. W.
    • Wilhelm, W. W.
  • Source: Agronomy Journal
  • Volume: 78
  • Year: 1986
  • Summary: Crop residues (stover) have many potential uses by society: food, feed, shelter, fuel, and soil amendment. Use of residues for purposes other than as a soil amendment may have serious negative consequences on crop productivity. This study was conducted to investigate the yield response of continuous corn (Zea mays L.) and continuous soybean [Glycine max (L.) Merr.) to removal or addition of crop residues under no-tillage management. The study was conducted near Lincoln, NE, on a Crete-Butler silty clay loam (fine, montmorillonitic, mesic Pachic Arguistoll-Abruptic Argiaquoll) with 1 to 2% slope. Crop residue was collected and weighed immediately after harvest in autumn. Quantity of residue to be returned to each treatment (0, 50, 100, or 150% of that produced) was calculated and uniformly spread over the plot area (12.2 by 12.2 m) by hand. Corn and soybean were planted into the established residue levels with no tillage the following spring. Data were collected on soil water, soil temperature, and grain and residue yield. A positive linear response was found between grain and stover yield and amount of residue applied to the soil surface. Each Mg ha-1 of residue removed resulted in about a 0.10 Mg ha"1 reduction in grain yield and a 0.30 Mg ha-1 reduction in residue yield. Quantity of applied residue accounted for 81 and 84% of the variation in grain yield of corn and soybean, respectively, and 88 and 92% of the variation in residue yield. Amounts of stored soil water at planting were closely associated with quantity of residue applied the previous year. Differences in total available water (soil storage at planting plus rainfall) accounted for approximately 70% of the yield variation associated with the residue treatments. Soil temperature (50-mm depth) and total available water accounted for nearly the same amount of variation in yield (80 to 90%) as quantity of residue, emphasizing the importance of these factors in evaluating response of crops to residue-management practices. Residue removal reduced grain and residue yields by amounts equal to 10 and 30%, respectively, of the quantity of residue removed. Residue effects on crop yield were induced mainly through changes in soil water and soil temperature.
  • Authors:
    • McCormick, B.
    • Dekker, J.
  • Source: Proceedings, North Central Weed Control Conference
  • Issue: Vol. 41
  • Year: 1986
  • Summary: Results are summarized of a long-term study started in 1985 at Boone County, Iowa, to determine the effect of several annual and perennial cover crops on maize and soyabean yields. Best soyabean yields were obtained with annual cover crops, Kentucky bluegrass ( Poa pratensis) and the bare soil control. Best maize seed yields were obtained with the bare soil control, winter rapeseed and winter barley cover crops.
  • Authors:
    • Miller, M.
    • O'Halloran, I.
    • Arnold, G.
  • Source: Canadian Journal of Soil Science
  • Volume: 66
  • Issue: 2
  • Year: 1986
  • Summary: In 1981, phosphorus absorption by young corn plants was greater from no-till than from plowed plots with similar NaHCO 3-extractable P (Ext P) concentrations. A series of growth room studies was conducted to explain this difference. Corn plants grown on cores from the no-till plots had a higher P concentration than plants grown on soil from the plowed plots, in spite of a lower root growth and a lower Ext P content. Disturbance of the no-till soil eliminated the effect. A parameter, accessible P (Acc-P), was calculated from root length and Ext P assuming P was absorbed from a cylinder of soil around each root. Shoot P content at a given Acc-P content was always higher with the undisturbed no-till soil than with either the disturbed no-till or the plowed soil. Irradiation (gamma-ray) of the no-till soil reduced P absorption by a similar degree to disturbance, indicating that a biological factor was involved. Disturbance of soil had no influence on P content of canola ( Brassica napus L.), a nonmycorrhizal crop. Soil disturbance reduced the intensity of mycorrhizal infection in corn roots. It is hypothesized that disturbance of the no-till soil reduced P absorption by reducing the effectiveness of the mycorrhizal symbiosis.
  • Authors:
    • Larson, W. E.
    • Moldenhauer, W. C.
    • Morachan, Y. B.
  • Source: Agronomy Journal
  • Volume: 64
  • Issue: 2
  • Year: 1972
  • Summary: When well-fertilized corn (Zea mays L.) monocultures with large amounts of residues returned to the soil became common, the question was asked as to whether soil tilth and corn yields could be maintained at satisfactory levels in Corn Belt soils. To answer this question corn growth and soil physical properties were determined in a field experiment in which different types (alfalfa (Medicago sativa L.), cornstalks, sawdust, oatstraw (Avena sativa L.) and bromegrass (Bromus inermis Leyss)) and amounts (from O to 16 tons/ha/yr) of plant residues were added to Marshall silty clay loam (Typic Hapludoll) for 13 consecutive years. The soil was cropped to corn and large amounts of N were added. For approximately the first 9 years grain yields were lower from the check and sawdust treatments than from all others. During the last 4 years grain yields declined sharply with rate of addition of cornstalk residues and slightly from additions of alfalfa. It is suggested that the yield decline in the cornstalk treatments was due to a lowering of pH and an Al-induced Ca deficiency in the plant. An alternative explanation is that the cation balance was upset as evidenced by K/Ca and K/Ca + Mg ratios in the plant. The C content of the soil was progressively increased, as was the wet aggregate stability and water retention with rate of addition of organic material. Energy of aggregate rupture, energy to initial runoff, erosion, and infiltration were not significantly influenced. It was not visually evident that significant changes occurred in soil tilth because of treatment differences. Marshall soils are well aggregated, have favorable physical and chemical properties, and although erosive, physical problems are not usually observable in the field. Corn grain yields averaged near 7,000 kg/ha (112 bu/acre) in the later years of the experiment, again suggesting that the physical properties of the soil on all treatments were favorable.
  • Authors:
    • Zhu, X.
    • Zhuang, Q.
    • Qin, Z.
  • Source: GLOBAL CHANGE BIOLOGY BIOENERGY
  • Volume: 7
  • Issue: 1
  • Summary: This study estimated the potential emissions of greenhouse gases (GHG) from bioenergy ecosystems with a biogeochemical model AgTEM, assuming maize (Zea mays L.), switchgrass (Panicum virgatum L.), and Miscanthus (Miscanthus נgiganteus) will be grown on the current maize-producing areas in the conterminous United States. We found that the maize ecosystem acts as a mild net carbon source while cellulosic ecosystems (i.e., switchgrass and Miscanthus) act as mild sinks. Nitrogen fertilizer use is an important factor affecting biomass production and N2O emissions, especially in the maize ecosystem. To maintain high biomass productivity, the maize ecosystem emits much more GHG, including CO2 and N2O, than switchgrass and Miscanthus ecosystems, when high-rate nitrogen fertilizers are applied. For maize, the global warming potential (GWP) amounts to 1-2 Mg CO2eq ha-1 yr-1, with a dominant contribution of over 90% from N2O emissions. Cellulosic crops contribute to the GWP of less than 0.3 Mg CO2eq ha-1 yr-1. Among all three bioenergy crops, Miscanthus is the most biofuel productive and the least GHG intensive at a given cropland. Regional model simulations suggested that substituting Miscanthus for maize to produce biofuel could potentially save land and reduce GHG emissions.