Small Research Plots Research Articles

Applicator for Spreading Liquid Manures on Small Research Plots

AbstractFarm‐size liquid‐manure pressure or vacuum tanks are not well suited for applying manure to research plots. It is difficult to manuever the spreaders and accurately control the flow of manure. This report describes an inexpensive liquid‐manure spreader developed for use on research plots (i.e., 4.6 by 12.2 m). The spreader has been used to apply manure as broadcast or injected treatments at rates of 18 000 to 80 000 L ha−1. This spreader can also be used to hand‐apply manure to very small (1.5 by 1.5 m) plots.

Agronomic Performance and Stability of Soybean Varieties Grown in Three Maturity Zones of Minnesota

Soybeans [Glycine max (L.) Merr.] grown in the northern latitudes generally have lower protein concentrations than in the southern latitudes, reducing the value of northern grown soybeans. The objectives of this research were to: (i) study maturity zones within Minnesota for soybean seed yield, protein concentration, and oil concentration; (ii) compare performance of soybean varieties grown in producers' yield-contest fields with University of Minnesota research plots; and (iii) analyze seed yield, protein concentration, and oil concentration means and stability statistics for 30 soybean varieties. Yield, protein, and oil data were collected from University of Minnesota research trials across 15 environments from 1991 to 1995. Producer data were collected from the Minnesota Soybean Grower's Association Yield Contest from 1991 to 1995. The general trend was a decrease in yield and protein concentration from southern to northern Minnesota, with higher yield and protein concentration among the same varieties grown in central Minnesota compared with northern Minnesota. Yields were highest in producers' yield-contest fields, but no protein and oil concentration differences were noted between yield-contest fields and research plots. Seed yield, protein concentration, and oil concentration means, as well as three stability statistics, differed among 30 varieties grown in 15 environments. The three stability statistics consisted of two nonparametric statistics based on variety ranks and Kang's yield-stability statistic. These results suggest that stability statistics, in addition to variety means, could be used by consultants, variety testing personnel, and breeders to recommend the most appropriate varieties for maximum yield and protein concentration.

A TRACTOR-MOUNTED IRRIGATION SYSTEM SIMULATOR FOR CHEMIGATION RESEARCH

An improved system for the application of chemicals in irrigation water to small research plots was designed,constructed and evaluated. The system was tractor-mounted with a three-point hitch for easy removal from the tractor. Ithad application booms on both sides of the tractor with full jet nozzles spaced 51 cm (20 in.) apart for chemigation andmicrosprinklers spaced 1.8 m (6 ft) apart for a pivot-attached sprayer system (PASS). The operators platform, locatedbehind the tractor and in front of the spray booms, carried the injection system, injection pumps and chemical tanks.Water was supplied to the system from a 38-mm (1.5-in.) diameter drag hose or from a nurse tank towed behind thetractor. The injection pumps were powered by an auxiliary generator attached to the tractor. Research plots treated by thesystem were 5.5 m (18 ft) wide by the desired length. The system had the capacity to apply 2.5 to 6.3 mm (0.1-0.5 in.) ofirrigation water or 1900 to 2800 L/ha (200-300 g/a) of chemical mixture for the PASS. The water application depth wascontrolled by varying the velocity of the tractor and/or the pressure of the irrigation or PASS nozzles. The system wascalibrated for water application depth and coefficient of uniformity (CU) and subsequently evaluated for the applicationof insecticides on whorl-stage corn (Zea mays) during 1995. Chemigation water depth and CU increased linearly withsystem pressure but was not significantly influenced by nozzle height above catch cups.

Influence of previous crop type on yield of spring wheat: Analysis of commercial field data

Although rotational benefits of non-cereal crops have been observed in small plot research trials few quantitative data are available on a field scale. In this study, field data of farmers from the Manitoba Crop Insurance Corporation were analysed to compare yield of wheat (Triticum aestivum L.) following different crops. The yield of wheat following wheat was used as a basis of comparison among crop sequences. The yield data were collected between 1982 and 1993 from fields 64 ha in size, located throughout the province of Manitoba. During this period, the yield of wheat following flax (Linum usitatissimum L.), peas (Pisum sativum L.), and canola (Brassica napus L.), on average was 16%, 11%, and 8% higher, respectively, than wheat following wheat. In one year, the yield of wheat was increased by as much as 41% following a field pea crop. Key words: Crop rotation, barley, canola, flax, field pea, wheat

Rotational Benefits of Forage Crops in Canadian Prairie Cropping Systems

Including perennial forages in cropping systems is recognized as one of the best ways to enhance agricultural sustainability. While rotational benefits of forages have been established in small plot research trials, there is no documentation of whether these benefits are being observed on commercial farms, or whether producers manage forage stands to maximize rotational benefits. A survey of 253 Manitoba and Saskatchewan producers known to include forages in their crop rotations was conducted in 1992. The survey area was divided into six agroclimatic zones and correspondence analysis was used to test whether responses differed across the survey area. Sixty-seven percent of respondents indicated a yield benefit from including forages in the crop rotation, with the greatest yield benefit observed in welter zones of the survey area. Eighty-three percent of the respondents observe weed control benefits for one (11% of respondents), two (50% of respondents), or more (33% of respondents) years after forages. The majority of respondents indicated that their forage acreage would not increase in the future. Average forage stand duration varied significantly (P < 0.10) with agroclimatic zone, ranging from 3 to 5 yr in welter areas (south-central Manitoba) to 6 to 9 yr in the driest areas (south Saskatchewan). The two most common reasons cited for forage stand termination were reduced forage yield and damage by pocket gophers (presumably Thomomys talpoides and Geomys bursarius). Less than 12% of respondents cited rotational considerations as their primary reason for terminating forage stands, indicating that producers are not managing their forage crops to maximize rotational benefits. Producers relied heavily on tillage in both forage crop establishment and forage stand termination phases of the production system. It was suggested that decreasing the amount of tillage and fallow associated with forage-based cropping systems would not only facilitate increased cycling of forages in rotations, but also increase agricultural sustainability.

A Modified Stimpmeter for Small-plot Turfgrass Research

Golf ball roll is measured with a United States Golf Association (USGA) Stimpmeter. Three Stimpmeters were fabricated identically to the USGA Stimpmeter, except for the location of the ball release notch. The modified Stimpmeters had ball release notches located at 57, 38, and 19 cm, rather than at 76 cm from the beveled end. The modified Stimpmeters were tested on a creeping bentgrass green located at Mead, Neb., at three mowing heights (4.8, 4.0, and 3.2 mm). The Stimpmeters were effective in measuring golf ball roll distance and provided reasonable and consistent estimates of friction. Modified Stimpmeters are relatively inexpensive to construct and can be used on small turfgrass research plots.

Evaluating cotton response to free‐air carbon dioxide enrichment with canopy reflectance observations

Most approaches for monitoring plant growth and development have serious drawbacks which limit their use in agricultural research programs. First of all, traditional methods for measuring above-ground green leaf area index (LAI) and biomass are very labor intensive, tedious and time consuming to execute. The size, number and frequency of samples required to characterize the plant canopy and detect statistically significant differences between treatments are usually large and often not practicable because of constraints on labor and space for cold storage and oven drying. Destructive sampling techniques are usually not appropriate in small research plots because the removal of some individuals from the population alters the response of remaining plants. Furthermore, the time required for physically separating leaves from stems and measuring them with a leaf area meter or waiting for tissues to dry in an oven precludes the use of these data in real-time decision making processes. Thus, important information that has immediate utility for assessing the efficacy of different treatments, identifying incipient problems, or guiding future sampling efforts is typically not available until several days or weeks after the samples have been collected. Non-invasive, remote sensing techniques which use plant canopy reflectance to monitor changes in canopy conditionmore » avoid these problems while providing scientists with an efficient tool for research and management of their projects. 19 refs., 9 figs., 10 tabs.« less

In-Situ Comparison of Bioremediation Methods for a Number 6 Residual Fuel Oil Spill in Lee County, Florida

ABSTRACT On July 5, 1988, as a result of overfilling, about 3,200 barrels of No. 6 fuel was spilled onto surface soils surrounding a Florida Power and Light Company storage tank, and spread over about 60,000 square feet of soil. About 2,300 barrels were recovered, leaving 900 barrels in the upper six to eight inches of the soil. The spill was chosen as the site for a trial of in-situ enhanced bioremediation. An initial feasibility study in the laboratory was followed by groundwater monitoring, field remediation, and a small-plot research program. In the feasibility study, lower concentrations of nutrients applied periodically were almost as effective as a single application using a larger concentration. The small-plot study indicated that treatment with added bacteria and nutrients offered the greatest reduction in hydrocarbons. Addition of bacteria alone provided no advantage. In the field remediation program, two- and three-ring compounds were completely degraded, while four-, five-, and six-ring compounds were more resistant. The research demonstrated that in-situ enhanced bioremediation can be a cost-effective method for treating soils contaminated with No. 6 fuel oil.

Automated, variable speed PTO for a plot-sized potato harvester

A single-row potato harvester, commonly used in small plot research, was modified to allow the operator to set the harvester chain speed independently of both the ground speed and the tractor engine speed. The modification has greatly increased the utility of the harvester for small research plots.

Field Measurement of White Mold Effects upon Dry Beans with Genetic Resistance or Upright Plant Architecture1

White mold of dry beans (Phaseolus vulgaris L.) is caused by the fungus pathogen Sclerotinia sclerotiorum (Lib.) de Bary, which can reduce crop yields 30 to 80% in irrigated regions. To reduce disease‐caused losses, germplasm improvement programs are incorporating sources of genetic resistance and desirable plant architectural traits into commercially acceptable market types. This field study was conducted to develop a small plot research technique to measure white mold effects under differential disease pressure, and to test parental and breeding lines for their potential in controlling disease. Sixteen entries were selected for their known resistance to the pathogen and their diverse plant growth habits. Experiments were conducted in 1982, 1984, and 1985 in a Nunn clay loam (fine, montmorillonitic, mesic Aridic Argiustolls) infested with sclerotia of the pathogen. Small research plots (6 m2) treated with benomyl |l‐(butylcarbamoyl)‐2‐benzimidazolecarbamate] and untreated control subplots effectively and reliably differentiated between cultivars and lines susceptible to and less affected by the pathogen on the basis of disease intensity and yield potential. Plant growth habit was not an acceptable predictor of the ability to escape white mold infection, because some Type I (bush) lines were as susceptible as Type III (prostrate vine) lines. Some Type II (upright vine) entries such as ‘A 51’ and ‘83 VEF MXA 222’ had significantly (P = 0.05) less white mold than did other entries in untreated plots. Resistant entries such as P.I. 169787 performed well despite having a Type I habit with compact canopy. Lines having resistance and desirable plant architecture have been identified and incorporated into the germplasm improvement program at Colorado State University.

All-terrain Vehicle to Apply Pesticides for Small-plot Research

An all-terrain vehicle (ATV) was modified to apply pesticides for small-plot pesticide research. The system involves custom design of a pesticide container rack and a boom that is attached to a four-wheel ATV (Suzuki LT-125). Initial costs for this spraying system were considerably more than for the conventional bicycle spraying system. Annual expenditures of labor, however, are considerably less for the ATV system. Five years of operation are necessary to show a positive return compared with a customized bicycle spraying system. Only 2 yr are necessary for the ATV system to be economical compared with a commercially available bicycle spraying system. A complete description, including costs, for construction of the ATV system is provided.

Estimating Yields of Red Raspberries in Small Research Plots

Abstract Estimated yields were compared to actual yields of red raspberries (Rubus idaeus L.) from research plots planted in stool beds at Abbotsford, B.C. and Invergowrie, Scotland and in hedge rows at Healesville in Victoria, Australia. Estimated yields, based on fruit set on 2 canes immediately prior to the start of harvest multiplied by the mean weight of 50 fruit taken at least 5 times throughout the harvest season, accurately assessed yield of the plots at all 3 locations. Accuracy of estimates was improved if plots had similar cane numbers and numbers of canes sampled were increased.

Commercial Production of Wheat Grain Irrigated with Municipal Waste Water and Pump Water

AbstractExperiments were conducted in southern Arizona to study the effects of irrigating wheat (Triticum aestivum L.) with a mixture of pump water and waste water and with pump water alone on wheat growth, grain yield, grain quality, soil properties, and irrigation water quality.In small plot research, wheat irrigated with the pump water‐waste water mixture produced taller plants, more heads per unit area, heavier seeds, higher grain yields, and higher straw yields than did wheat grown with only pump water. When large fields were compared, wheat grown with the pump water‐waste water mixture had taller plants, more lodging, lower grain volume‐weights, and higher grain yields than did wheat produced with pump water.The pH and exchangeable sodium of soil irrigated with pump water alone or the pump water‐waste water mixture were similar. Soluble salts and nitrate‐nitrogen were higher in soils irrigated with pump water than they were in soils irrigated with the pump water‐waste water mixture. Extractable phosphorus was higher in soils irrigated with the pump water‐waste water mixture than in soils irrigated with pump water.Total soluble salts and nitrate‐nitrogen were higher in pump water than they were in the pump water‐waste water mixture; however, the pump water‐waste water mixture had higher levels of total nitrogen and phosphorus than did pump water. The higher grain yields obtained when wheat was irrigated with the pump water‐waste water mixture than were produced when wheat was grown with pump water alone probably resulted from lower concentrations of soluble salts in the pump water‐waste water mixture than were present in pump water.

Yield Differences between Research Plots and Managed Forests

Abstract Differences between timber yields on small research plots and on managed forests are due mainly to differences in definition of forested area, in scale and quality control of management treatments, and in uniformity of the stands. In large areas where management has not yet made stands uniform, research results may serve only as general guides to potential growth. The manager who is practicing some degree of intensive forestry can often find research data on which to base accurate estimates of growth and yield. To apply the information, he must exclude unproductive areas from estimates of his acreage, monitor stands for damage, and supervise treatments efficiently. There is, however, no single magic number that adjust for differences in growth between research plots and larger managed forests.

Grass Seed Harvester for Small Plots1

A seed‐head harvester consisting of a gasoline‐powered hedge trimmer and an aluminum tray is described. This harvester greatly facilitates harvesting grass seed of small research plots and reduces labor requirements to one‐fifth that of hand harvesting.

High‐Clearance Sprayer for Small Plot Research1

AbstractA high‐clearance sprayer equipped with compressed air and electronic controls provided a versatile system for small plot research. The large solution tank was replaced with a rack to carry eight (or more) solution tanks each of which could be connected to a separate spray nozzle arrangement. Various combinations of spray rate, solution, and nozzle arrangements were instantly available to the operator

Root Plow Herbicide Application as a New Incorporation Technique

A new method was developed for incorporating herbicides into the root zone of saltcedar (Tamarix pentandraPall.) in arid, low rainfall areas. A spray pipe with five nozzles was mounted along the rear edge of a 2.44-m root plow blade. A supply line connected the spray pipe with a sprayer mounted on the plow frame. In operation, the saltcedar roots were severed at a selected depth by the blade as herbicide was sprayed simultaneously into the cut-root zone. A similar root plow with a 1.22-m blade was designed for use on small research plots.

An Area‐List Method of Measuring Range Plant Populations

In the past, the Forest Service has used several different methods of measuring vegetation quantitatively in studying the relationship between herbaceous plant populations and range management (Forsling, '25). While these methods have provided data necessary for solution of the problems involved, they are limited in their application or else do not yield data sufficiently reliable for all purposes. The most widely used of these methods involves an ocular estimate of the density and composition of the vegetation on natural range units or on small research plots. Whereas this method is useful for determining major plant relationships, its susceptibility to error due to misjudgment by inexperienced or poorly trained observers and the limited amount of specific data obtained, make it objectionable from a research standpoint. Mere knowledge of the amount and character of the vegetation, although invaluable in making up a grazing plan for administrative use, is insufficient for an understanding of the exact nature and the causes of changes in plant population. The quadrat method is another widely used system for recording changes in the plant cover (Hill, '20; McGinnies, '30). This system is accurate and provides unlimited data, including a permanent record of the exact location and the size and shape of the basal cross-section of every perennial plant within a definite area. Nevertheless, it too has its shortcomings. Owing to the small size (usually 1 sq. m.) of each sample, it is necessary to establish four or more quadrats for any given condition in order to obtain a reliable record of the changes occurring under that condition. It is impossible generally to maintain a sufficient number of quadrats for each set of conditions involved because of the time required for charting. Hence quadrats are used chiefly to supplement more extensive methods of describing the vegetation. A third method typified by the list-quadrat system in which the individuals of each species occurring within a plot are carefully counted, has been used to some extent (Hanson and Ball, '28). While the resultant data indicate the composition of the vegetation, it does not show the quantity of vegetation on the ground in terms of density or volume. In other words, the method is highly satisfactory for qualitative analysis, but is limited for quantitative measurement to the comparison of areas on which the plant composition is similar and composed largely of single stalked species. It is not applicable to grasses or other turf-forming plants. Because of these deficiencies, the 573