No-till Continuous Corn Research Articles

Symposium A sustainable agriculture project at Chesapeake Farms: a six-year summary of weed management aspects, yield, and economic return

Abstract A 6-yr project comparing four cash grain–farming systems relevant to the mid-Atlantic region of the United States was conducted from 1993 to 1999. A wide range of parameters was sampled including soil health, nutrient and agrichemical movement, economic viability, and insect and weed communities. The systems and their approaches to weed management were: continuous no-till corn without (System A1) or with (System A2) rye cover crop and preplanned herbicides based on expected weed infestations; System B was a 2-yr corn–soybean rotation with conventionally tilled corn and no-tillage soybean, with preplanned herbicides based on expected weed infestations; System C was a 2-yr rotation with no-till corn, conventionally tilled wheat, and no-till double-cropped soybean, using postemergence (POST) herbicides on the basis of field scouting; and System D was a 3-yr rotation of corn-soybean-winter wheat with rye and hairy vetch cover crops, using cultivation and reduced rates of POST herbicides based on fiel...

Residual effects of potassium placement for conservation-till corn on subsequent no-till soybean

Biannual surface application of potassium (K) fertilizer prior to corn ( Zea mays L.) in a corn–soybean ( Glycine max (L.) Merr.) rotation has been common in conventional-till crop production in North America; however, whether this traditional K management practice is effective for soybean when both corn and soybean are grown with conservation tillage is largely unknown. This study evaluated the residual effects of spring K fertilizer placement in conservation tillage systems applied to previous corn on subsequent no-till soybean. Experiments involving a corn–soybean rotation were conducted from 1997 to 2000 on a silt loam soil (Albic Luvisol) with 12 years of continuous no-till management near Paris, Ontario, Canada. The fields had low initial soil-test K levels (<61 mg l −1) and evident soil K stratification in the top 20 cm. In the “corn” years from 1997 through 1999, spring K fertilizer placement methods of deep band (76 cm centers), surface broadcast, broadcast plus shallow band, and no K were evaluated for no-till, spring zone-till, and spring mulch-till tillage systems (1997 and 1998) but for no-till alone in 1999. From 1998 to 2000, soybean was no-till planted in 19 cm row widths on the respective previous-year corn treatments without further K fertilizer application. Soybean leaf K concentrations responded more frequently and positively to K application in no-till corn than in zone-till and mulch-till corn. Deep band and surface broadcast K placements were similar in their residual effects on soybean leaf K. Positive soybean yield responses to residual K fertilizer were observed in only 1 out of 3 years despite consistent increases in both soil K and soybean leaf K concentrations where K was applied to previous corn. On long-term no-till fields with low soil K levels, interrupting a continuous no-till corn–soybean system with mulch-till corn production provided residual benefits in soil K availability and leaf K nutrition for subsequent no-till soybean. Furthermore, the residual effects of K fertilizer applied to previous corn on subsequent no-till soybean were not affected by K placement method.

Tillage System and Crop Rotation Effects on Dryland Crop Yields and Soil Carbon in the Central Great Plains

Winter wheat (Triticum aestivum L.)–fallow (WF) using conventional stubble mulch tillage (CT) is the predominant production practice in the central Great Plains and has resulted in high erosion potential and decreased soil organic C (SOC) contents. This study, conducted from 1990 through 1994 on a Weld silt loam (Aridic Argiustoll) near Akron, CO, evaluated the effect of WF tillage system with varying degrees of soil disturbance [no‐till (NT), reduced till (RT), CT, and bare fallow (BF)] and crop rotation [WF, NT wheat–corn (Zea mays L.)–fallow (WCF), and NT continuous corn (CC)] on winter wheat and corn yields, aboveground residue additions to the soil at harvest, surface residue amounts at planting, and SOC. Neither tillage nor crop rotation affected winter wheat yields, which averaged 2930 kg ha−1. Corn grain yields for the CC (NT) and WCF (NT) rotations averaged 1980 and 3520 kg ha−1, respectively. The WCF (NT) rotation returned 8870 kg ha−1 residue to the soil in each 3‐yr cycle, which is 2960 kg ha−1 on an annualized basis. Annualized residue return in WF averaged 2520 kg ha−1, which was 15% less than WCF (NT). Annualized corn residue returned to the soil was 3190 kg ha−1 for the CC (NT) rotation. At wheat planting, surface crop residues varied with year, tillage, and rotation, averaging WCF (NT) (5120 kg ha−1) &gt; WF (NT) (3380 kg ha−1) &gt; WF (RT) (2140 kg ha−1) &gt; WF (CT) (1420 kg ha−1) &gt; WF (BF) (50 kg ha−1). Soil erosion potential was lessened with WCF (NT), CC (NT), and WF (NT) systems because of the large amounts of residue cover. Levels of SOC in descending order in 1994 were CC (NT) ≥ WCF (NT) ≥ WF (NT) = WF (RT) = WF (CT) &gt; WF (BF). Although not statistically significant, the CC (NT) treatment appeared to be accumulating more SOC than any of the rotations that included a fallow period, even more rapidly than WCF (NT), which had a similar amount of annualized C addition. Reduced tillage and intensified cropping increased SOC and reduced soil erosion potential.

Assessing tillage- and cropping-induced changes in relative conductivity

Although changes in relative hydraulic conductivity(Krc) in the surface soil layer can have significantimpact on transport of water and solutes below this layer, experimentaldetermination of Krc is laborious and expensive. In thisstudy, a simple theoretical equation has been used to compute near-surfaceKrc and assess its sensitivity to tillage- andcropping-induced near-surface changes in soil porosity (.epsi;), porecontinuity (PC), and soil water content (θ). The data were collected in1994 from a cropping and tillage system experiment established in 1988 on asilt loam soil. The tillage treatments were conventional and no-till. Thecropping treatments were continuous corn (Zea maize L.)under conventional cultivation (CT corn), corn following forages(alfalfa,Medicago sativa L.; and bromegrass,Bromus inermis L.) under conventional and no-till (NTcorn) practices, and continuous no-till corn. Soil bulk density (r ) and inthe near surface (depth, 0-2 ·5 cm) soil layer were measured in lateJuly 1994 subsequent to changes in tillage and cropping practices in May 1994.Only tillage differences had significant influence on ρ, θ, fractaldimension (D), PC, and Krc of the near-surface soillayer. A switch from no-till forages to CT corn resulted in increases in andD, and decreases in ρ , θ, and Krc. Theintroduction of NT corn into forage-terminated plots did not producesignificant changes in the above properties compared with continuous NT corn(7 years old), which was characterised by smaller values of and PC, and highθ and Krc. Water content, , and PC accounted for96% of the variability in Krc. The results showedthat the near-surface changes in Krc can be predictedwith high accuracy using the data on only ρ and θ which are easy togather.

CULTIVATOR DESIGN FOR INTERROW WEED CONTROL IN NO-TILL CORN

More than 95% of Iowa row crop acres are treated with herbicides. Such extensive use is an environmentalconcern. Banding of herbicides over the crop row, along with mechanical cultivation to control interrow weeds, has beenproposed as a way to reduce herbicide use. Though cultivation is used on 74% of Iowa corn (Zea mays L.) land,herbicides are applied in a band on only 17% of the corn acres. This indicates that cultivation is not relied upon forinterrow weed control. The risk that weather conditions will hinder completion of mechanical cultivation seems todiscourage the use of herbicide banding. Higher speed cultivation could improve the odds of timely completion of neededcultivation. An experiment was conducted on a Clarion loam soil near Boone, Iowa in 1993 through 1996 to determinethe effect of cultivator design and speed, when combined with the banding of chemicals, to control weeds. Three cultivatorstyles, two bands [19 cm (7.5 in.) and 38 cm (15 in.)], and two speeds were tested. A single cultivation managementstrategy was used. Data were taken in a no-till continuous corn rotation on 76-cm (30-in.) row spacings.<br><br>Faster speed did not impede weed control or yield. In two years, the corn yield was greater and weed cover wasreduced in plots cultivated at 11.2 km/h (7.0 mph) than in plots cultivated at 6.4 km/h (4.0 mph). Weed populations weregreater in the 19-cm (7.5-in.) band than in the 38-cm (15-in.) band three of four years. In three of four years, leaf heightsand yields were also significantly less for herbicide applied in a 19-cm (7.5-in.) band than in a 38-cm (15-in.) band. Therewas no difference between yield in a broadcast treatment and treatments which used a wide band of herbicide and acultivator with disc hillers. In two years, the sweep and smith fin (a vee-shaped flat sweep with low rake angle) cultivatortreatments resulted in less weed cover than the point-and-share treatment. In one year, the sweep and smith fin cultivatortreatments had greater yield than the point-and-share treatment. Groundcover among cultivators showed few differences.

Effect of Tillage and Rotation on Agronomic Performance of Corn and Soybean: Twenty-Year Study on Dark Silty Clay Loam Soil

In the U.S. Corn Belt, tillage without plowing was used on more than 50% of corn (Zea mays L.) and soybean (Glycine max (L.) Merr.] acreage in 1994, while no-till planting was used on about 30% of the acreage. Few research studies have evaluated these reduced tillage systems for 20 yr or more. This study includes plow, chisel, ridge, and no-till systems in continuous corn, corn after soybean, soybean after corn, and continuous soybean rotations. The experiment was conducted on Chalmers (fine-silty, mixed, mesic Typic Haplaquolls) silty clay loam soil in north-central Indiana for 20 yr. Objectives were to determine the effect of tillage and rotation on stands, growth, maturity, and yield of corn and soybean and to determine trends that develop with time for these variables. Major stand reductions occurred only in no-till continuous corn, 8% less than plowing. Compared with plowing, chisel and ridge tillage systems reduced growth and yield and increased harvest moisture by less than 3% in continuous corn. No-till reduced 4-wk height of continuous corn by 17%, yield by 14%, and increased harvest moisture by 2.1 percentage points compared with plowing. For corn following soybean, only no-till corn showed a yield reduction, 2.8%, compared with plowing. Twenty-year mean soybean yield reductions averaged 4 to 7% in both rotation and monoculture for chisel, ridge, and no-till systems compared with plowing. Relative yields for no-till continuous corn tended to be less than other tillage-rotation systems over time, while no-till soybean yields tended to improve with time, especially during the last 5 yr of the study. Both corn and soybean yields were better in rotation than in continuous cropping for all tillage systems. Of the tillage systems-rotation combinations in this study, only no-till continuous corn is likely to suffer major yield loss on a long-term basis on dark prairie soils of the Central and Northern Corn Belt.

Effect of Paraplowing on Crop Yields with No-Till Planting

No-till acreage has expanded rapidly in the past 5 yr in the U.S. Corn Belt. Yield potential often improves with no-till planting on well drained and low organic matter (OM) soils, but no-till yields are sometimes at a disadvantage on dark, poorly drained soils. Restricted plant rooting due to increased soil density is sometimes reported with no-till planting. Deep tillage with a Paraplow 1 (Tye Co., PO Box 218, Lockney, TX 79241), leaving most surface residue undisturbed, was evaluated on three soils in Indiana for continuous corn (Zea mays L.). Annual paraplowing and biennial paraplowing were used with no-till and moldboard plow systems. On dark, poorly drained silty clay loam, annual paraplowing improved stand, growth, and yield, compared with traditional no-till planting. On a silt loam soil with 2% OM, response to paraplowing for no-till was variable and on a 1% OM soil, paraplowing did not improve no-till yield. Carryover effect from biennial paraplowing for no-till planting was not consistent, even on silty clay loam. Paraplowing did not improve plowed yields on any of the three soils. Paratilling was also used on four rows of each 12-row plot in the 15th year of a long-term tillage study on silty clay loam soiL Plow, chisel, ridge, and no-till systems were used in continuous corn, corn after soybean [Glycine max (L.) Merr.], soybean after corn, and continuous soybean. In no-till continuous corn, there was a positive response to paratilling, but yield for no-till plus paratilling was significantly lower than plowed yield. With conditions similar to conditions in these studies, deep soil loosening is likely to improve no-till continuous corn yield on dark poorly drained soil, but is not likely to improve yield on well drained or low OM soils where traditional no-till is well adapted.

Seasonal Changes in Flow and Nitrate-N Loss from Subsurface Drains

Subsurface drainage from thirty-six, 0.4-ha plots was monitored for three years (1990 to 1992) from chisel plow, moldboard plow, ridge till, and no-till systems with continuous corn and corn-soybean rotations. Data were analyzed in four seasonal stages to determine variations in drain flows and nitrate-N contents in drain effluent. The hypothesis of this study was that differences among tillage systems would change during the monitoring season as rainfall patterns varied and as plots were fertilized and cultivated. Forty-five to 85% of the annual nitrate-N loss through subsurface drainage occurred in the spring and fall when crops were not actively growing. These losses, however, were not significantly different among tillage systems. Relative changes in drain flows and nitrate-N concentrations before and after summer cultivation were similar among the four tillage systems even though no-till and ridge till systems were undisturbed before this time. Nitrate-N losses or concentrations did not increase during the stage following fertilizer application. No-till plots had significantly higher subsurface drain flow than moldboard plow plots only under continuous corn, possibly an effect of reduced yields from long-term no-till continuous corn. Nitrate-N concentrations in drain effluent from moldboard and chisel plow systems, however, were significantly greater than concentrations from no-till and ridge till systems for all crop rotations. Lower nitrate-N concentrations from no-till and ridge till systems may have resulted from greater bypass flow, denitrification, and immobilization under nonplowed systems.

Effect of Lumbricus terrestris L. burrows on hydrology of continuous no-till corn fields

This paper reviews research performed at the USDA-Agricultural Research Service, North Appalachian Experimental Watershed, Coshocton, Ohio into the importance of earthworm burrows, primarily those made by Lumbricus terrestris L., on the hydrology of no-till corn fields. Long-term runoff records showed that infiltration and therefore, potential ground water recharge, could increase by more than 100 mm yr −1 in watersheds farmed with no-till practices as compared to similar fields that were conventionally tilled. The difference in hydrologic response appeared to be due to differences in soil physical properties, possibly those attributable to earthworm activity. When crop residues were left on the surface under continuous no-till corn management, earthworms thrived and their large, nearly vertical burrows persisted. Field studies showed that dye and chemical tracers applied in simulated rainfall moved in the earthworm burrows. The number and sizes of burrows and other macropores were determined and water and nitrate movement in > mm diameter burrows were measured. Flow in these earthworm burrows during 12 growing season storms accounted for an average of 4% of rainfall, (range 1–10%) or 13 times more than would be predicted based solely on their cross-sectional area. Total movement of nitrate in the burrows during these 12 storms was estimated to be <1 kg ha −1.

Consecutive Annual Applications of Alachlor and Metolachlor to Continuous No-Till Corn (Zea mays)

Consecutive annual applications of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] were made to continuous no-till corn (Zea maysL. ‘Pioneer 3184’ in 1982 and 1983, ‘Pioneer 3744’ in 1984, and ‘Pioneer 3378’ in 1985 to 1987). In a 5-yr study, control of the dominant annual grass species, large crabgrass [Digitaria sanguinalis(L.) Scop. # DIGSA], by alachlor declined to less than 50% by the fifth year. Control of large crabgrass by metolachlor remained greater than 80% throughout the study but metolachlor allowed the establishment of a greater fall panicum (Panicum dichotomiflorumMichx. # PANDI) population in this and an additional 3-yr study than in chloroacetamide-free checks. In the 3-yr study in which giant foxtail (Setaria faberiHerrm. # SETFA) was dominant, annual applications of metolachlor and a microencapsulated formulation of alachlor provided better control in the second year than the emulsifiable concentrate formulation of alachlor, but formulation differences diminished in the third year.

Characterizing Macropores that Affect Infiltration into Nontilled Soil

A 0.5-ha watershed of Rayne silt loam on 9% slope at Coshocton, Ohio was farmed for 20 yr in continuous no-till corn (Zea mays L.). With average rainfall >1 m/yr, runoff from this mulch-covered surface averaged <2 mm/yr. Previous dye studies show that even at low rainfall rates, water moves rapidly through vertically continuous macropores (mainly earthworm burrows) in this field that hasn't been tilled since 1960. To characterize the distribution of these pores, we photographed cleaned, horizontal 30.5- by 30.5-cm2 surfaces at depths of 2.5, 7.5, 15, and 30 cm. The images were scanned with an image analyzer to count and determine the size of open pores. With eight replications at each depth, total number of pores >0.4 mm in diameter per m2 of surface area ranged from 3369 to 21 151 in the 2.5-cm depth and from 5673 to 28 966 at the 30-cm depth. The overall average was 14 576 pores per m2, 160 of which were >5 mm in diameter. Mean pore diameter ranged from 1 to 2 mm at all depths and the number of pores was inversely proportional to pore diameter. There were more pores at the lower depth than near the surface. Pores >0.4 mm in diameter accounted for approximately 1.4% of the total area.

Seventy five years of arthritis research at the Strangeways Research Laboratory: 1912-87.

<h3>ABSTRACT:</h3> Nitrate contamination of shallow groundwater has been widely documented in association with agriculture in the Coastal Plain region of the Chesapeake Bay watershed. Elevated groundwater nitrate levels limit the use of shallow groundwater for human consumption and also result in elevated nonpoint source nitrogen (N) loads to Chesapeake Bay via elevated stream base-flow nitrate concentrations. This study investigated the effects of cereal grain winter cover crops on nitrate leaching rates, profile nitrate storage, and nitrate concentrations in shallow groundwater in two field-scale watersheds planted continuously in corn (Zea mays L) from 1984 through 1996. Winter-fallow conditions were maintained following the 1984 through 1987 growing seasons and cereal rye (Secale cereale L.) as a cover crop was planted immediately after grain harvest from 1988 through 1996. Cover crop effects on nitrate leaching rates also were evaluated in continuous no-till corn plots from 1990 through 1995. Nitrate leaching losses from the root zone and recharge of ‘shallow aquifers occurred primarily during winter months under conditions of law evapotranspiration’. The potential for nitrate leaching losses was determined primarily by the availability of nitrate in the root zone at the onset of the winter groundwater recharge period. Rye winter cover crops planted after corn harvest consistently reduced nitrate-N concentrations in root zone leachate to less than 1 mg/L during most of the groundwater recharge period, and reduced annual nitrate leaching losses by approximately 80% relative to winter-fallow treatments. Shallow groundwater nitrate-N concentrations under long-term continuous corn production decreased from the 10 to 20 mg/L range to less than 5 mg/L after seven years of cover crop use. Cover crops appeared to increase corn yields under adverse growing season conditions, but limited residual nitrate availability during the growing season relative to winter-fallow settings. Cover crop growth was generally N limited, suggesting that increased N inputs would have little effect on nitrate leaching, but would increase cover crop contributions to soil carbon pools.

Field Corn, Northern Corn Rootworm Larval Control, 1979

Abstract The test field had been in continuous no-till corn for 4 years. Corn was planted no-till in 30 inch, 3 row plots, 95 ft long with 4 replications in a randomized block design. Thirty-five insecticide-rate combinations were compared. The treatments were evaluated by root damage ratings based on the Iowa 1-6 system and on yield. Stand establishment was also observed. Only 3 materials had a stand density of less than 104 per 100 row ft. All treatments except Furadan 4F at 0.25 and 0.5 lb and Furadan 10G at 0.25 lb significantly reduced rootworm danage in comparison with the untreated check. The Furadan 4F and FMC 35001 4E formulations did not perform comparable to these same chemicals formulated for granular treatment. The more than average precipitation during the summer season may have accounted for this reduction in efficacy.