Cereal Plots Research Articles

Occurrence and productivity of songbirds in prairie farmland under conventional versus minimum tillage regimes

Abundance and productivity of common bird species in prairie cropland under either conventional or minimum tillage were examined in southern Alberta, Canada. Cover types included spring cereals, winter wheat and summerfallow. Productivity was assessed using observations of nesting and brood-rearing behavior. Five species were sufficiently abundant to allow for some statistical analyses: horned lark ( Eremophila alpestris), savannah sparrow ( Passerculus sandwichensis), Baird’s sparrows ( Ammodramus bairdii), chestnut-collared longspur ( Calcarius ornatus) and McCown’s longspur ( Calcarius mccownii). Abundance varied between conventional and minimum tillage regimes for most species in at least one cover type. Savannah sparrows in spring cereal and winter wheat and chestnut-collared longspurs in summerfallow tended to prefer minimum tillage. McCown’s longspurs and horned larks occurred more frequently on conventional than minimum till spring cereal plots in at least 1 of the 2 years. For savannah sparrows, minimum till spring cereal and winter wheat were more productive than conventional till habitat. Summerfallow of either tillage regime did not appear to be as productive as minimum till cereal fields for this species. Chestnut-collared longspurs occurred predominantly in minimum till summerfallow and spring cereal habitat and showed almost no productivity in conventionally managed plots. McCown’s longspurs tended to have higher productivity in minimum till plots. Horned larks had high productivity in minimum till winter wheat in 1996. Male Baird’s sparrows occupied territories in minimum till winter and spring cereal fields in 1995, but did not attract mates; they were not detected in 1996. Minimum tillage appeared to confer benefits in productivity to species that nested in farmland.

Towards the archaeobotanical identification of intensive cereal cultivation: present-day ecological investigation in the mountains of Asturias, northwest Spain

The region of Asturias, northwest Spain, is highly unusual in that a cereal crop (spelt wheat) is cultivated on a garden scale using horticultural methods. A floristic survey was made of the weeds in 65 spelt plots in this region. The ecological attributes of the weed species were then measured and compared to an earlier study of the functional characteristics of weeds associated with pulse crops on the Greek island of Evvia. In this earlier study, it was possible to distinguish between plots cultivated intensively on a garden-scale and plots cultivated extensively in fields, on the basis of a suite of functional attributes of the weed species. The cereal plots from Asturias were correctly identified as gardens on the basis of the same suite of attributes. The Asturias plots were also compared to weed associations from autumn- and spring-sown crops in Germany, using a different suite of attributes, and were classified either as autumn-sown or ambiguously. This is consistent with the sowing time in Asturias, which is spread over late autumn to winter. These results demonstrate that the suites of functional attributes identified to distinguish intensive and extensive cultivation, and to recognise sowing time, can be applied in another geographical area and to another crop type. This paves the way for the application of these attributes to the identification of past agricultural practices from archaeological weed assemblages.

Effect of Soybean Plant Populations in a Soybean and Maize Rotation

Plant population of soybean [Glycine max (L.) Merr.] may influence the residual N contribution to a cropping system and yield benefits to following cereals. Field studies were conducted from 1994 to 1996 on a N‐depleted Sharpsburg silty clay loam soil at Mead, NE to: (i) determine soybean yield at different plant populations; (ii) investigate residual N, chlorophyll–N–yield relations, and yield benefits from these different soybean populations to a following maize (Zea mays L.) crop; (iii) and compare N credits from soybean assessed with fallow and cereal plots as references. Eight soybean populations from14 000 to 544 000 plants ha−1 in narrow 50‐cm rows, a fallow plot, and a maize plot were followed by maize in a rotation study. Soybean yield was highest at populations of ≥129 000 plants ha−1. Maize grain yields were highest following fallow and soybean populations <20 000 plants ha−1, intermediate following higher soybean populations, and least in continuous maize. This is most likely due to N uptake as indicated by chlorophyll and N accumulation of maize. Nitrogen credits to maize were 16 to 46 kg N ha−1 when calculated as Nitrogen Fertilizer Replacement Values (NFRVs). This is probably overestimating the potential N contribution from soybean because N credits from soybean populations assessed with fallow instead of maize as references were negative. A net positive N balance due to soybean reached a maximum of 17 kg N ha−1, but soil N was depleted at populations <20 000 plants ha−1. We conclude that yield increases of maize in rotation with soybean may be due to N from reduced N immobilization, N added to the soil from N2 fixation, and possibly from non‐N rotation effects such as water use efficiency.

Cereal/legume rotation effects on cereal growth in Sudano-Sahelian West Africa: soil mineral nitrogen, mycorrhizae and nematodes.

Yield increases of cereals following legumes in rotation have been previously reported for West Africa, but little progress has been made to explain the mechanisms involved. At four sites in Niger and Burkina Faso, field trials with pearl millet (Pennisetum glaucum (L.) R. Br.), cowpea (Vigna unguiculata (L.) Walp), sorghum (Sorghum bicolor (L.) Moench) and groundnut (Arachis hypogaea L.) were conducted from 1996 to 1998 to investigate the role of soil mineral nitrogen (Nmin), native arbuscular mycorrhizae (AM) and nematodes in cereal/legume rotations. Grain and total dry matter yields of cereals at harvest were increased by legume/cereal rotations at all sites. Soil Nmin levels in the topsoil were consistently higher in cereal plots previously sown with legumes (rotation cereals) compared with plots under continuous cereal cultivation. However, these rotation effects on Nmin were much larger with groundnut than with cowpea. Roots of rotation cereals also had higher early AM infection rates compared to continuous cereals. The dominant plant-parasitic nematodes found in all experiment fields were Helicotylenchus sp., Rotylenchus sp. and Pratylenchus sp. In sorghum/groundnut cropping systems, nematode densities were consistently lower in rotation sorghum compared to continuous sorghum. Continuous groundnut had the lowest nematode densities indicating that groundnut was a poor host for the three nematode groups. In millet/cowpea cropping systems with inherently high nematode densities, crop rotations barely affected nematode densities indicating that both crops were good hosts. These results suggest that on the nutrient poor Sudano-Sahelian soils of our study, total dry matter increases of rotation cereals compared with continuous cereals can be explained by higher Nmin and AM infection levels early in the season. The site-specific magnitude of these effects may be related to the efficiency of the legume species to suppress nematode populations and increase plant available N through N2-fixation.

Strategies to decrease nitrate leaching in the Brimstone Farm Experiment, Oxfordshire, UK, 1988-1993: the effects of winter cover crops and unfertilised grass leys

Nitrate losses in drainflow were measured over five years on eight hydrologically isolated field plots, pairs of which had the following cropping regimes: (a) a 3-yr unfertilised, ungrazed grass ley followed by winter and spring cereals, (b) mixed cropping including winter cover crops, spring cereals, winter cereals, winter fallow and spring beans, (c) a similar sequence to (b) but with a winter fallow replacing the cover crop in the first year and a winter cover crop replacing the fallow in the third year, and (d) continuous winter cereals (control plots). Less nitrate was lost in winter drainflow from winter cover crops than from the winter fallows, but over all five years less nitrate was leached from the continuous cereal plots than from those with mixed cropping. Most of the extra nitrate lost from the mixed cropping regimes probably resulted from mineralisation of the cover crop residues, which occurred at times when subsequent crops could not take advantage of the mineral nitrogen released. Crops grown after the grass ley and cover crops did not benefit from their residues, in terms of either grain yield or of total nitrogen uptake. We conclude that on heavy clay soils in UK a cropping regime of continuous winter cereals offers the best compromise between profitable crop production and minimised nitrate loss to surface waters.

Potential of using field spectroscopy during early growth for ranking biomass in cereal breeding trials

The use of field spectroscopy for the non-destructive ranking of cereal breeding plots at the early stages of crop growth was investigated using measurements of spectral reflectance over 222 wavebands between 400 and 2500 nm using the single beam GEOSCAN Portable Field Spectroradiometer (PFS). Measurements were made on 54 barley plots at the 5- and 7-leaf stages of growth with biomass varying between 10 and 96 g/m2. The optimal multiple linear regression relationship between reflectance and biomass included wavebands from the near-infrared (NIR) and mid-infrared (MIR) with a standard deviation of 4.8 g/m2. The ranking of plots according to biomass by this optimal relationship or the Simple Ratio of NIR to visible (VIS) reflectance, which is a common index of greeness, agreed closely with actual ranking. Tested against an independent set of wheat plots at the 4-leaf stage with biomass ranging from 3 to 32 g/m2, the barley-derived relationship, but not the Simple Ratio, performed poorly in ranking plots according to biomass. However, at the 7-leaf growth stage, when the biomass range had increased to 48-117 g/m2, both the Simple Ratio and the barley-derived relationship agreed closely with the actual ranking. To apply these results in practice, the accuracy of the simpler CROPSCAN portable field radiometer (PFR) was found to be greater than the GEOSCAN PFS for comparable NIR and VIS wavebands. It was therefore concluded that it is practically feasible to use field spectroscopy to rank cereal plots for biomass at early growth stages where the difference between plots is of the order of 5-7 gm/m2. Such biomass differences were more apparent at the 7-leaf than 4-leaf stage of growth.

Use of reflectance measurements to estimate early cereal biomass production on sandplain soils

High early biomass production has been suggested as a useful selection criterion for improving cereal yields in mediterranean environments. Current methods for measuring biomass production in cereal plots involves destructive sampling which is not suitable for routine use by plant breeders where large numbers of samples are to be screened. The measurement of spectral reflectance using ground-based remote sensing techniques has the potential to provide a nondestructive estimate of plant biomass production. This field study investigated the relationship between spectral reflectance and early biomass production in barley and wheat and assessed the feasibility of using spectral reflectance techniques in cereal-breeding programs. Spectral reflectance measurements (0.40-2.5 �m wavelengths) were made before stem elongation for barley and wheat grown in separate experiments at Wongan Hills, Western Australia. Cereal biomass was closely associated with spectral reflectance in the visible (0.44-0.66 �m) and mid infrared (1.50-1.80 �m and 2.00-2.40 �m) regions, but not in the near infrared (0.71-1.10 �m). The poor correlation between reflectance in the near infrared region and biomass production was due to the low amounts of biomass present and the high reflectivity of the sandplain soils at these wavelengths. The close associations in the visible and mid infrared regions provides promise for use in estimation of cereal biomass, but further research is required to refine the technique for use in large scale breeding programs.

Atrazine persistence and phytotoxicity on wheat as affected by nitrogen and rotation-induced changes in soil properties

Wheat growing in a rotation experiment on an alkaline black earth was severely damaged by atrazine residues, whereas wheat in an adjacent experiment on a slightly acid red clay, was undamaged. Atrazine at 1.8 kg a.i, ha-1 had been applied to both sites nine months before wheat sowing. Nitrogen fertilizer had also been applied as split-plot treatments to the previous crop in each rotation sequence. There were four rotations, each comprising grain sorghum with either lucerne, an annual grain legume, long fallow, or continuous cereal growing.There were significant rotation effects on soil organic matter, pH, mineral nitrogen and residual atrazine. Organic carbon was highest, and soil pH and atrazine were lowest in the lucerne rotation, while the opposite occurred in the long fallow treatment. Atrazine concentration was positively correlated with pH and negatively correlated with organic carbon. The numbers of dead plants on the black earth were positively correlated with atrazine levels, but mortality was lowered by increasing mineral nitrogen at any particular level of atrazine.Wheat yields varied from zero in two continuous cereal plots to over 3.0 t ha-1 in a long fallow plot, and were highly correlated with mineral nitrogen levels. At any level of nitrogen, however, wheat yields were depressed by increasing levels of atrazine. The very large yield response to nitrogen, whether from soil or fertilizer, resulted from its dual beneficial effect of lowering plant mortality and improving the nitrogen status of the surviving plants.These results show that in a wheat crop following atrazine-treated sorghum, significant atrazine damage may occur on soils of pH > 64, that atrazine persistence and phytotoxicity will increase as the pH increases, but that phytotoxicity will decrease as soil nitrogen fertility increases. Lucerne rotations will lower atrazine persistence by decreasing soil pH and increasing organic matter, and will lower phytotoxicity by raising soil nitrogen.

Leaching losses of nitrogen from a clay soil under grass and cereal crops in Finland

A 16-plot experimental field was established in 1975 on a clay soil in Jokioinen, Finland. The water discharge through tile drains was measured and its ammonium and nitrate N contents determined for each plot separately. The surface runoff was also measured and analysed. The annual runoff and the N leached from the surface of moderately fertilized (100 kg/ha/y N) cereal plots varied during 1976–1982 from 21 to 301 mm and from 2 to 7 kg/ha, respectively. The discharge of water and leaching of N through subdrains varied from 65 to 225 mm and from 1 to 38 kg/ha, respectively. The highest leaching was probably caused by a previous fallow. The annual N uptake by the crop varied between 41 and 122 kg/ha.

The effects of intercropping with cereals and minimal permethrin applications on insect pests of cowpea and their natural enemies in Nigeria

Abstract Major insect pests and their natural enemies were sampled on cowpea in monocrop and cereal intercrop plots in southern and northern Nigeria. Populations of flower thrips, Megalurothrips sjostedti (Trybom), were reduced by 42% and predators, mostly Orius spp. (Anthocoridae), by 23% on cowpea in maize intercrop plots at Ofiki in the south. Infestation by pyralid pod borer, Maruca testulalis Geyer, was unaffected by cropping system. The results suggest that tasselling maize attracts flower‐eating beetles (Meloidae) to intercrop plots, and that pod‐sucking Hemiptera were increased by cereal intercrops at Yankara in the north. Three u.l.v. applications of permethrin at 150 g a.i./ha to monocrop cowpea reduced pest populations by 50 to 85% in the south and increased yield sevenfold. However, the sprayed crop in the north was lost due to a heavy infestation of pod‐sucking bug, Clavigralla tomentosicollis Stal, and outbreaks of Aphis craccivora Koch on sprayed plots in both localities suggested damage to...

A Combination Belt, Cone and Vacuum Seeder for Experimental Cereal Plots1

AbstractA drill is described which combines the desirable features of belt, cone, and vacuum seeders. The drill and tractor unit is easily portable in the back of a pickup truck. We are using the drill primarily to seed wheat and barley nurseries, but it could be used equally well for a variety of other crops.

An automatic self-propelled seed drill for cereal plots

An automatic self-propelled seed drill for cereal plots

A combine drill for cereal plots

A combine drill for cereal plots

THE INFLUENCE OF IRRIGATION, FERTILIZING AND MCPA ON THE COMPETITION BETWEEN SPRING CEREALS AND WEEDS

Summary. The average air‐dry yield of weeds on fallow plots was about four times as large (2660 kg/ha) as the yield of weeds which developed among spring cereal crops (740 kg/ha). Application of fertilizers increased the number of weeds and their average weight on both irrigated and non‐irrigated plots. Treatment with MCPA reduced the weed yield to 36% on fallow plots and to 26% on weedy cereal plots. It was more effective on fertilized plots than on unfertilized plots, but irrigation made little difference to its effectiveness. The space left by the destroyed weeds was mainly occupied by Agropyron repens. Oats were better able to compete with weeds than were wheat and barley. On unfertilized and non‐irrigated plots spraying with MCPA (1‐26 kg/ha) at the beginning of shooting significantly reduced the yields of weed‐free barley. The yields of sprayed oats and wheat were also below the yields from the unsprayed although the reductions were not significant at the 5% level. However, on a number of fertilized and irrigated plots, both weedy and hand‐weeded, on which the plants had better growing conditions, MCPA resulted in a significant increase in the grain yield of barley and oats.Influence de l'irrigation, de la fertilisation et du MCPA sur la compétition entre céréales de printemps et mauvaises herbes

THE OCCURRENCE OF FUSARIUM SPECIES IN CANADA: IV. TAXONOMY AND PREVALENCE OF FUSARIUM SPECIES IN THE SOIL OF CEREAL PLOTS

A taxonomic study was made of 12,485 isolates of Fusarium that were obtained from a total of 1674 soil samples taken from two series of permanent cereal plots during the years 1936–1942. Isolates of Fusarium averaged approximately 16% of total fungus isolates. A total of 16 species, varieties, and forms of Fusarium, classified in eight sections of the genus, were isolated. These species, varieties, and forms are F. dimerum Penz., F. merismoides Cda., F. poae(Pk.) Wr., F. sporotrichioides Sherb., F. avenaceum (Fr.) Sacc., F. concolor Rg., F. semitectum Berk. & Rav., F. acuminatum Ell. & Ev., F. equiseti (Cda.) Sacc., F. culmorum (W. G. Sm.) Sacc., F. sambucinum var. coeruleum Wr., F. sambucinum f. 6 Wr., F. oxysporum Schlecht, em. Snyder & Hansen, F. oxysporum var. redolens (Wr.) Gordon, F. solani (Mart.) App. & Wr. em. Snyder & Hansen. The majority of the species isolated were encountered each year. F. oxysporum and F. equiseti, together, accounted for approximately 75% of the total Fusarium isolates. Average concentrations per gram of soil of these two species were approximately 4800 and 2300 'units', respectively. Average concentrations per gram of soil of each of the remaining species isolated were below 600 units. Except for F. dimerum and F. merismoides, the species, varieties, and forms that were obtained from soil have been isolated previously from the basal parts and seed of cereals in the Prairie Provinces.

Studies in Sampling Technique: Cereal Experiments. I. Field Technique.

Preliminary experiments carried out in the summer of 1928 had indicated that sampling methods might be used to obtain a satisfactorily precise estimate of the yield of small cereal plots(1). It was thought desirable to test the method more thoroughly, and to compare the estimates with figures obtained by large-scale methods. Accordingly samples were taken from all the plots of the three Rothamsted cereal experiments of 1928, the plots later being harvested with a binder in the ordinary manner. Samples were also taken from the 16 plots of a small experiment on barley at Wellingore, Lines., but no direct measurement of total yield was made for these plots. There were 210 plots in all, but of these 50 were sampled in four sections, corresponding with minor differences in manurial treatment; so that the total number of plots dealt with amounted to 360. The large-scale method, however, treated each of the 50 as a single plot, and thus provided only 210 yield figures.

The estimation of yield in cereal crops by sampling methods

1. Cereal plots were sampled by three different methods; two systematic, and one involving a random location of sampling units.2. The disadvantages of the systematic methods as compared with random sampling, emerged clearly.3. These disadvantages were further emphasised in an analysis of earlier data on sampling methods. For this purpose the methods and. results of certain recent contributions to statistical theory were used.4. By the use of a random sampling method, the variance due to sampling errors may be made a satisfactorily small fraction of the total variance of cereal plots one-fortieth of an acre in area.