76-cm Rows Research Articles

Effect of subsoiling and subsequent tillage on soil bulk density, soil moisture, and corn yield

Many producers use subsoilers periodically to alleviate suspected compaction caused by traffic from tillage, planting, and harvesting equipment. In the fall of 1988 a study was initiated in the upper Midwest region of the USA near Morris, Minnesota to study the effects of a one-time subsoiling and its interaction with four subsequent primary tillage systems (fall moldboard plowing, fall chisel plowing, spring disking, and no-tilling) on soil compaction, soil moisture, penetrometer resistance, and corn ( Zea mays L.) growth and grain yield. The experiment was established on a Hamerly clay loam (Aeric Calciaquoll)-Aastad clay loam (Pachic Udic Haploboroll) complex. Subsoiling was performed in the fall of 1988 and the study was cropped to continuous corn from 1989 to 1991 on a site that had been farmed many years by normal 6-row, 76-cm row width equipment. Results show that subsoiling had very little effect on plant growth and no effect on grain yield over three cropping seasons following the subsoiling operation. Subsoiling had significant effects on soil bulk density and volumetric soil moisture content in 1989, but by 1990–1991 these effects were not significant. Volumetric soil moisture content generally increased in relation to soil bulk density increases. Tillage impacted surface residue accumulation, but did not affect soil bulk density, volumetric soil moisture, or grain yield. Results from this study indicate that subsoiling soils does not necessarily result in better yields or better soil moisture availability, particularly if compaction problem are not evident.

Crop density and seed production of creeping red fescue (Festuca rubra L. var. rubra). 2. Reproductive components and seed characteristics

The natural growth habit of creeping red fescue (Festuca rubra L. var. rubra) involves a steady proliferation of tillers which eventually become too dense to form seedheads. The effects of the initial density (1.6, 3.1, 6.3, 12.5, 25, 50 and 100 plants m−2) and row spacing (20, 40 and 80 cm) on reproductive components and seed characteristics of red fescue were studied in a northerly environment for three production years (1991–1993) The weight proportion of cleaned to uncleaned seed decreased as density increased, from 82% at 1.6 plants m−2 to 60% at 100 plants m−2. The thousand-seed weight was 1.20–1.54 g (i.e., 830 000–650 000 seeds kg−1) and decreased as density increased. The specific seed weight was 16–25 kg hL−1; it differed among years and decreased as density increased. The germination capacity of the seed was unaffected by density but differed among years, averaging 87, 92 and 69% in the three consecutive production years. The seed yield per plant, the number of seedheads per plant, and the number of seeds per plant decreased exponentially as the density increased. The number of seeds per seedhead decreased as density increased in the first year but was less affected subsequently, except in the third year at 50 and 100 plants m−2 on 20-cm rows, when no seeds were matured. The seed yield was correlated closely with the number of seedheads per square metre, which increased with density in the first year but decreased as density increased in the two subsequent years. A relatively high density of well-spaced plants is required at establishment to optimize seedhead formation in the first crop but is detrimental to seedhead formation and seed yield subsequently. Key words: Red fescue; Festuca rubra var. rubra, population density, plant and row spacing, yield components, seed quality

Influence of Narrow Row/High Population Corn (Zea mays) on Weed Control and Light Transmittance

Field experiments were conducted from 1989 to 1992 to determine whether no-tillage corn grown in 38-cm rows and a 2× population could improve weed control relative to 76-cm rows and 1× population under reduced-herbicide options. A standard treatment including 1.12 kg ai/ha of atrazine plus 2.24 kg ai/ha of metolachlor was compared with a treatment including the same herbicides applied at 25% of the standard rates. Both treatments included 0.56 kg ai/ha of paraquat which controlled annual weeds established at the time of application. Weed control was less in the 25%-herbicide treatment than in the standard treatment in two of four years when corn was grown in 76-cm rows with a l× population. The 25%-herbicide treatment provided weed control and grain yields similar to the standard treatment in each year when corn was grown in 38-cm rows with a 2× population. Weed control was poor and yield was reduced when no herbicides were applied regardless of row spacing or population. The leaf canopy of corn in the 38-cm row/2×-population treatment reduced light transmittance 1 wk earlier than corn in the 76-cm row/1×-population treatment.

Effects of row spacing, seeding rate and nitrogen on yield of barley and wheat under zero-till management

Adopting water-conserving tillage practices on the Canadian prairies will protect the soil against erosion while conserving soil water. The use of tall-standing stubble to conserve water creates a dilemma for producers because maximum yields can only be obtained with narrow rows, and tall stubble may limit the use of narrow row spacings. A 4-yr study on a thin Black clay soil investigated the effects of three row spacings (10, 20 and 30 cm), six seeding rates (34, 67, 100, 134, 168 and 202 kg ha−1 for wheat and 27, 54, 81, 108, 134 and 161 kg ha−1 for barley) and two rates of N (low and high) in hard red wheat (Triticum aestivum L.), durum (Triticum durum L.) and barley (Hordeum vulgare L.) using a continuous cropping, zero-till production system. The yields of cereals were maintained with 30-cm row spacing over a wide range of growing conditions under zero-till management. Durum had a 5.8% yield advantage and barley a 2.4% advantage for the 30-cm row spacing over the 10-cm row spacing. The number of plants established and the number of spikes produced decreased as row spacing increased for all crops. But wider row spacing resulted in more kernels produced per spike, which, in the case of barley and durum, more than compensated for the lower number of spikes. Increasing seeding rates significantly improved grain yield in all crops and years because more spikes were produced. Grain yield was related to the reciprocal of seeding rate. The few row spacing × seeding rate interactions observed in 2 of 12 cases suggest that seeding rates need not be adjusted for changes in row spacing. The results obtained have important implications for equipment design and the ability to more easily handle high-crop-residue situations. Key words: Yield components, seeding rate, row spacing, yield compensation

Cropping system influences on extractable water for mono- and double-cropped soybean

For rain-fed agriculture in the southeastern United States, efficient soil water use when double-cropping is essential. Water use by soybean [ Glycine max (L.) Merr.] following winter wheat ( Triticum aestivum L.) is, however, poorly documented. Winter wheat may deplete soil water, thus limiting subsequent soybean yield. Cropping system variables, such as soybean planting date and row spacing, may also affect water use. Therefore, a 4-year field experiment in northeastern Mississippi was conducted on Leeper ( Vertic Haplaquept) and Catalpa ( Fluvaquentic Hapludoll) silty clays. The objectives were to (1) determine the influence of soybean planting date, cropping system (monocropped versus double-cropped), and row spacing on extractable water (similar to available water) for soybean, and (2) identify a production system to improve the use of extractable water over a growing season. In mid- to late-May (the first soybean planting date), “Centennial” soybean in 38- or 76-cm rows was planted either between rows of standing wheat or in bare (monocropped) plots. After the wheat was harvested and the straw chopped, soybean was planted into bare soil or planted no-till into wheat stubble in mid-June for the second planting and in early July for the third. Soil water content was measured with a neutron probe from soybean emergence to maturity. Differences between each water content profile and a dry profile (constructed using the lowest recorded water content at each depth) were regarded as extractable water. Neither soybean planting date nor cropping system, as a main effect, exerted much influence on extractable water for soybean. As interacting factors later in the season, however, they were important. Plots with soybean in 38- rather than 76-cm rows contained more extractable water throughout the 1982 and 1983 seasons, and yielded over 9% more seed. Canopies closed about 20 days sooner with narrow rows than with wide rows. These full canopies protected and shaded the soil surface, probably reducing crusting and decreasing water losses by evaporation. We concluded that double-cropped soybean in 38-cm rows planted either into standing wheat in late May or into wheat stubble not later than mid-June utilized extractable water efficiently in silty clay soils in northeastern Mississippi.

Giant Ragweed (Ambrosia trifida) Canopy Architecture and Interference Studies in Soybean (Glycine max)

Field experiments were established at Columbus and near South Charleston, OH to determine the effects of giant ragweed population density on soybean yield and to characterize the development of giant ragweed grown in 76-cm soybean rows. An economic threshold was calculated for Ohio using a common treatment for giant ragweed control in soybean. A cost of $41/ha was estimated for a farmer to apply 0.56 kg/ha bentazon plus 0.28 kg/ha fomesafen plus COC (1.25% v/v). Assuming a soybean value of $0.22/kg, the cost of control was equivalent to 5.4 and 7.1% of the soybean yield in 1991 and 1992, respectively, which corresponded to the yield loss caused by 0.08 and 0.03 giant ragweed plants/m2. The competitiveness of giant ragweed can be at least partly attributed to its ability to initiate and maintain axillary leaves and branches within the shaded confines of the soybean canopy.

Comparison of Economic Injury Levels for Western Corn Rootworm (Coleoptera: Chrysomelidae) Infesting Silage and Grain Corn

The effect of known densities of western corn rootworms, Diabrotica virgifera virgifera LeConte, on yield and monetary losses was compared for corn harvested as silage and as grain. In 1991 and 1992, plots were infested artificially with western corn rootworm eggs at densities ranging from 0 to 1,500 viable eggs per 30.5 cm of row. Level of rootworm feeding did not affect silage quality, as measured by percentage crude protein, acid detergent fiber, neutral detergent fiber, and nonstructural carbohydrates. Western corn rootworm caused greater yield reductions and dollar losses in corn grown for silage than for grain. Economic injury levels (EILs) were calculated for various combinations of crop use, yield potential, and crop value typical of corn production in the Northeast. Assuming an insecticide cost of $39.50 per ha, EILs for silage ranged from 71-127 viable eggs per 30.5 cm of row, corresponding to root ratings ranging from 2.5-2.9. In contrast, EILs were much higher for corn harvested for grain, ranging from 242-537 viable eggs per 30.5 cm of row, corresponding to root ratings ranging from 3.5-4.6.

Lima Bean (Phaseolus lunatus L.) Response to Irrigation Regime and Plant Population Density

`Maffei-15' lima beans were subjected to three irrigation regimes (natural rainfall only, partial = 50 mm each week of rain or irrigation from first-flower bud to harvest, and full = 50 mm each week of rain or irrigation from planting to harvest), two between-row spacings (38 and 76 cm), and two in-row plant spacings (5 and 10 cm). The wider in-row spacing increased individual plant vegetative growth but had no effect on economic yield. The combination of 38-cm rows and partial irrigation provided the highest crop growth rate, plant dry matter, leaf area index, water-use efficiency, and economic yieid (equivalent to 3.3 t·ha-1).

Radiation-use efficiency in relation to row spacing for late-planted soybean

Greater soybean [ Glycine max (L.) Merr.] yield can be achieved at late planting dates by using row spacings narrower than conventional wide rows (76 to 100 cm). Objectives were to determine the relative yield performances of 100−, 50−, and 25-cm row spacings in late-planted soybean and to relate yield differences to changes in yield components, several growth dynamic parameters, and radiation interception. Field studies were conducted at Baton Rouge, LA (30°N Lat.) from 1989 through 1991 at a late planting date with ‘Centennial’ soybean (Maturity Group VI) planted on 100−, 50−, and 25-cm row spacings. The test was conducted on a silty clay soil. Highest yield occurred with 50-cm row width. Yield in the 25− vs. 50-cm rows was less, even though light interception (LI) patterns were similar. Growth dynamic analysis revealed that radiation-use efficiency (RUE) during the first half of the seed filling period was significantly lower in 25− vs. 50− or 100-cm rows. Reduced RUE in 25-cm row spacing was related to reduced pod number associated with lower crop growth rate (CGR) from pod initiation to 10 days after seed initiation. Results indicate that factors other than optimal LI (95%) affect yield responses to row width.

Comparison of crop management effects on spring barley cultivars grown on three soil types in southwestern Quebec

There may be potential to increase grain yield and/or quality of barley (Hordeum vulgare L.) under the short crop-growing season conditions of Southwestern Quebec with intensive cereal management (ICM) practices similar to those used successfully in Europe. A field experiment was conducted for 4 yr (1987–1990) at the Macdonald Campus of McGill University to evaluate the applicability of ICM (140 kg N ha−1, 480 g a.i. ethephon ha−1, 70 g triadimefon ha−1 and 10-cm row spacing) vs. conventional cereal management (CCM) (70 kg N ha− and 20-cm row spacing) on spring barley. Four barley cultivars (Cadette, Joly, Laurier and Leger) were grown on three soil types: Bearbrook clay, St. Bernard loam and Chicot loamy sand. Grain yields of most cultivars were either unchanged or decreased 5–30% by ICM whereas Laurier occasionally yielded better under ICM than CCM. A general increase in spikes m−2 that resulted from ICM was largely offset by a reduction in grains per spike. Although ICM increased crude protein concentrations in grain and straw, use of 15N-labelled fertilizer showed a lower N recovery rate. The results indicated that yield response to ICM was inconsistent and was influenced to a large extent by prevailing weather and soil conditions. The ICM package tested is not applicable in this region. Key words: Conventional cereal management (CCM), intensive cereal management (ICM), 15N, nitrogen recovery, protein, soil type, spring barley

Peanut Response to Fluometuron Applied to a Preceeding Cotton Crop1

Abstract An experiment was conducted to determine the potential for fluometuron to carry over to peanut (Arachis hypogaea L.). Fluometuron was applied preemergence to cotton (Gossypium hirsutum L.) at 1.12 and 2.24 kg ai ha-1 as a broadcast spray or as a 30-cm band in 91-cm rows. Each preemergence application was followed by zero, one, or two postemergence-directed applications of fluometuron at 1.12 kg ha-1 plus MSMA at 2.24 kg ae ha-1 in a 30-cm band. Herbicide treatments did not adversely affect cotton yield or fiber quality. Fluometuron injury was not observed on peanut planted the following year. Peanut yield, grade, and value were not affected by previous fluometuron treatments.

The effects of nitrogen, row spacing and seeding rate on the yield of flax under a zero-till production system

The long-term sustainability of agriculture requires that soil degradation be addressed and that crop production systems that incorporate the benefits of surface residues and standing stubble through conservation tillage practices be evaluated critically. The objective was to study the effects of nitrogen, row spacing and seeding rate on the yield of flax (Linum usitatissimum L.) under zero-till production practices. Three row spacings, six seeding rates and two rates of nitrogen were investigated. The plots were directly seeded into barley stubble under a continuous cropping zero-till production system. When yield levels were > 1200 kg ha−1, yields were not significantly affected by row spacing, but when yield levels were < 1200 kg ha−1, the 20-cm row spacing was favored over the 10- or 30-cm spacings. Yields increased linearly with increase in seeding rate at all row spacings. There were no interactions observed between nitrogen, row spacing and seeding rate. The results of this study have important implications in terms of equipment design, cost for zero-till seeding equipment, and the opportunity to easily modify existing equipment for zero-till seeding. Key words: Plant establishment, plant height, zero till, yield

Biological Control of The Western Corn Rootworm Using an Entomoparasitic Nematode, 1992

Abstract Efficacy of Steinernema carpocapsae. All strain, as a biological control agent for WCR was evaluated on a Waukegan silt loam soil at the University of Minnesota Agricultural Experiment Station, Rosemount. Experimental plots, consisting of 30 plants in 30 rows of 10 (76-cm row spacing, planted 19 May), were infested on 9 Jun with 800 WCR eggs/30.5 cm of row. Sixty additional plants were infested to monitor WCR development. Most plants had reached the 2-leaf stage when infested; 20% were at the 1-leaf stage. A factorial design was used, testing nematode application rate and timing of application relative to WCR development. Nematodes (BioVector®) were applied on 4 dates, determined by rootworm development: before hatch (18 Jun), and when the population had reached its early 1st (29 Jun), 2nd (8 Jul), and 3rd instars (15 Jul). Fourteen ml of 0.15% agar S. carpocapsae suspension was applied around the base of treated plants with a 35 ml syringe. Four replicates of 4 nematode rates and an agar control were applied on each date. Soil conditions were highly favorable for nematode movement except for 8 Jul, when the plots were watered to ensure the top 10 cm of soil was uniformly moist. On 31 Aug, 10 roots from each plot were dug, washed, and rated using the Iowa 1-6 root injury scale (with half-point increments of greater sensitivity).

Effects of Tillage, Row Width, and Cultivar on Foliar Diseases of Double-Crop Soybean

Experiments were conducted over two years, 1985 and 1986, to determine the effect of tillage systems, row widths, and soybean cultivars on foliar diseases in double-crop soybean. The soybean cultivars Pershing, susceptible to bacterial blight, and Avery, resistant to bacterial blight, were each planted in 38-cm and 75-cm row widths in soil under conventional tillage or no-tillage following winter wheat. There was a significant interaction (P=0.0001) between tillage and cultivar for the severity of bacterial blight and a significant interaction (P=0.001) for tillage, cultivar, and year for the severity of brown spot. Tillage did not influence bacterial blight severity on Avery; however, disease severity was higher on Pershing soybean in tilled plots

Granular and Liquid Insecticide Performance Against Black Cutworm, 1992

Abstract This trial investigated the performance of granular insecticides at below-label rates applied at planting, rescue applications of liquid insecticides and a nematode (BioVector). Experimental plots were established in continuous corn field with a Waukegan silt loam soil at the Rosemount Agricultural Experiment Station. Plots measuring rows (76-cm row spacing) x 9 m, were arranged in a RCB design with 4 replications. Corn was planted on 20 May at a seeding rate of 64,500 seeds/ha. Granular treatments were applied at planting ahead of the presswheel using modified Noble applicators. Aluminum barriers, each surrounding 4.6 cm of 2 rows and extending 10 cm below and 15 cm above the soil, were installed 8 Jun when corn was just emerging. Corn stand within the barriers averaged 40 plants. On 9 Jun between 6 and 7 p.m. each plot was infested with 60 BCW larvae (50% 4th, 50% 3rd instars). The next morning, between 7-9 a.m., all liquid rescue treatments were applied within the appropriate barrier arenas. Liquid insecticides were applied in 187 liters of water/ha while the nematodes (BioVector) were applied in 750 liters/ha. Wind speed ranged from 0 to 3 km/h, while soil temperatures hovered near 22°C. Plots were examined 3, 6, and 10 d after infestation, injured plants were marked and plant injury was recorded as leaf feeding. Statistical analyses were performed after determining the final fate of each plant.

Row-spacing and seed-rate effects on winter wheat in Ontario

This study was carried out to determine if winter wheat in southwestern Ontario should be grown in rows narrower than the conventional 18 cm and if the current recommended seed rate of 3.2 million seeds ha−1 (msh) is adequate. We compared the effect of 10- and 20-cm row spacings and 1.6, 3.2, and 6.4 msh seed rates on grain yield, weed growth and yield of underseeded clover. Row spacing at a constant seed rate did not affect yield. With increasing seed rate there was an increase in yield, mainly through more heads per unit area, which more than compensated for a decrease in seeds per head. Narrow rows reduced the number of lamb’s-quarters and the overall weed count. The optimum seed rate for grain yield was 6.4 msh for ratios of seed cost:crop value less than 1.34. Key words: Narrow rows, weeds, yield, economic optimum

Yield and water use of paired-row versus equidistant-row seeded spring wheat in a semiarid environment

A field study was carried out to determine the effects of seed row configuration on days to maturity, water use and grain yield of spring wheat (Triticum aestivum L. ’Leader’) grown in a semiarid environment. From 1986 to 1989, Leader spring wheat was seeded at Swift Current, Saskatchewan in north-south equidistant-rows (25-cm row spacing) and paired-rows (two rows 10 cm apart with 50 cm between the centre of each paired row). Seed and fertilizer were applied at recommended rates for the Brown soil zone. There were no significant differences (P > 0.10) in grain yield, water use or days to maturity between equidistant-row and paired-row seeding. The data suggest that under the environmental conditions of the Brown soil zone paired-row seeding may have no agronomic advantage over equidistant-row seeding.Key words: Paired-row seeding, water use, grain yield, spring wheat

Biological Control of the Western Corn Rootworm Using An Entomoparasitic Nematode, 1991

Abstract Efficacy of Steinernema carpocapsae, All strain as a biological control agent for WCR was evaluated on a Waukegan silt loam soil at the University of Minnesota Agricultural Experiment Station, Rosemount. Experimental plots, consisting of 30 plants in 3 rows (76 cm row spacing) of 10, were laid out in a completely random design on 28 Jun, and infested with WCR eggs at 600 eggs/30.5 cm of row using the method of Branson and Sutter (1980). Most of the corn (planted 10 Jun) had then reached the 3 or 4-leaf stage. On 17 Jul, nematodes (BioVector° were applied. Approximately 11 ml of S. carpocapsae suspended in 0.15% agar were applied around the base of each treated plant with a 35 ml syringe. Control plants received agar only. Six replicates of 4 nematode rates and an agar control were used; although applied per-plant, rates are expressed as nematodes/30.5 cm of row. All plots were watered after treatment until the top 5 cm of soil appeared uniformly moist. Three WCR emergence cages were placed in each plot on 24 Jul, each covering 2 plants. Beetle traps were monitored weekly from 31 Jul through 23 Sep. On 17 Sep, 10 roots from each plot were dug, washed, and rated using the Iowa 1-6 root injury scale (with half-point increments of greater sensitivity).

Effect of Soybean (Glycine max) Row Spacing on Chemical Control of Sicklepod (Cassia obtusifolia)

Sicklepod control with seven chemical treatments was evaluated in 25-cm and 97-cm soybean row widths. Metribuzin applied preplant incorporated followed by metribuzin applied preemergence, and metribuzin applied preplant incorporated followed by either imazaquin or chlorimuron applied postemergence controlled sicklepod over 90% early in the season, and row spacing did not influence control at that evaluation. In late season ratings, all herbicide treatments controlled sicklepod better in 25-cm rows than in 97-cm rows. However, only imazaquin applied sequentially or metribuzin followed by chlorimuron in 25-cm rows controlled sicklepod greater than 80% late in the season. Sicklepod control in 25-cm row soybean with either imazaquin or metribuzin plus chlorimuron applied preplant incorporated was equivalent to or better than sequential preemergence and postemergence treatments of these three herbicides in 97-cm rows. All treatments resulted in lower yields than the weed-free check in the 97-cm rows, whereas all herbicide treatments except the sequential application of metribuzin gave yields equivalent to the weed free check in 25-cm rows.

Interference of Common Cocklebur (Xanthium strumarium) and Cotton (Gossypium hirsutum)

An area of influence method with biweekly destructive harvests 5 through 19 wk after planting (WAP) was used to monitor the reciprocal interference of common cocklebur and cotton in 1987 and 1988. Plant heights, leaf area, and leaf, stem, boll, fiber, and total plant biomass dry weights were measured in 15-cm increments away from common cocklebur or from a randomly selected cotton plant out to 105 cm. Data indicated that cotton less than 60 cm from common cocklebur was shorter, had less leaf area and lower leaf, stem, boll, and biomass dry weights than cotton beyond 60 cm from common cocklebur or cotton grown without common cocklebur interference. Differences in leaf area and biomass between cotton grown with and without common cocklebur interference were greater at and beyond 13 WAP sample dates than before 13 WAP. By 15 WAP, cotton leaf area and biomass were reduced an estimated 11% and 15%, respectively, averaged over the entire 105 cm of row. Cotton yield, harvested 27 WAP, was reduced an estimated 31% on plants grown with one common cocklebur plant per 2.1 m. Cotton yield was reduced on plants out to 99 cm from common cocklebur. Common cocklebur and cotton plants grown alone were taller, had greater leaf area, and greater leaf, stem, and biomass dry weight than those respective plants grown adjacent to cotton. Common cocklebur grown alone produced 67% more biomass than did cotton grown alone. Cotton plants grown adjacent to other cotton plants produced 89% and 96% less boll and fiber weight, respectively, than plants grown alone.