Dominant insectivorous polyphagous predators in winter wheat: High colonization power, spatial dispersion patterns, and probable importance of the soil surface spiders (Araneae)

The climate changes and increased drought frequency still more frequent in recent periods bring challenges to management with wheat straw remaining in the field after harvest and to its decomposition. The field experiment carried out in 2017–2019 in the Czech Republic aimed to evaluate winter wheat straw decomposition under different organic and mineral nitrogen fertilizing (urea, pig slurry and digestate with and without inhibitors of nitrification (IN)). Treatment Straw 1 with fertilizers was incorporated in soil each year the first day of experiment. The Straw 2 was placed on soil surface at the same day as Straw 1 and incorporated together with fertilizers after 3 weeks. The Straw 1 decomposition in N treatments varied between 25.8–40.1% and in controls between 21.5–33.1% in 2017–2019. The Straw 2 decomposition varied between 26.3–51.3% in N treatments and in controls between 22.4–40.6%. Higher straw decomposition in 2019 was related to more rainy weather. The drought observed mainly in 2018 led to the decrease of straw decomposition and to the highest contents of residual mineral nitrogen in soils. The limited efficiency of N fertilisers on straw decomposition under drought showed a necessity of revision of current strategy of N treatments and reduction of N doses adequately according the actual weather conditions.

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Response of winter wheat to prolonged waterlogging under outdoor conditions

The Journal of Agricultural Science ◽

10.1017/s0021859600036881 ◽

1981 ◽

Vol 97 (3) ◽

pp. 557-568 ◽

Cited By ~ 53

Author(s):

R. K. Belford

Keyword(s):

Winter Wheat ◽

Water Table ◽

Stem Elongation ◽

Soil Surface ◽

Root Production ◽

Or Efficiency ◽

Plant Nitrogen ◽

Stages Of Growth ◽

Nodal Root ◽

Waterlogging Treatment

SUMMARYThe response of winter wheat cv. Maris Huntsman to waterlogging was studied in two experiments in soil columns outdoors. Winter waterlogging treatments increased nodal root production and the proportion of aerenchyma within roots, but caused chlorosis and premature senescence of leaves, and decreased tillering. For all treatments, grain losses were much less than expected from the extent of tiller loss in winter; losses after single waterlogging events ranged from 2% (after 47 days with the water-table at 5 cm) to 16% (after 80 days with the water-table at the soil surface). Yield losses after three waterloggings at the seedling, tillering and stem elongation stages of growth were additive, and totalled 19%. In many treatments, grain loss was associated with lighter individual grain weights, suggesting that the size of the root system or efficiency of water and nutrient uptake by roots at the later stages of growth may have been less after earlier waterlogging. The importance of nitrogen fertilizer in maintaining a satisfactory plant nitrogen status was shown when nitrogen was with held before a 3-week waterlogging treatment during stem elongation; tiller and floret survival was subsequently greatly restricted and grain yields decreased 22% below those of plants waterlogged at the same stage of growth but supplied with nitrogen.

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Farming systems and conservation needs in the Northwest Wheat Region

American Journal of Alternative Agriculture ◽

10.1017/s0889189300006767 ◽

1996 ◽

Vol 11 (2-3) ◽

pp. 52-57 ◽

Cited By ~ 31

Author(s):

R.I. Papendick

Keyword(s):

Winter Wheat ◽

Water Conservation ◽

Soil Surface ◽

Farming Systems ◽

Winter Precipitation ◽

Water Erosion ◽

Residue Management ◽

Annual Precipitation ◽

Conservation Strategies ◽

No Till

AbstractThe Northwest Wheat Region is a contiguous belt of 3.3 million ha in Idaho, Oregon and Washington. Its climate varies from subhumid (<650 mm annual precipitation) to semiarid (<350 mm), with more than 60% of the annual precipitation occurring during the winter. Winter wheat yields range from a high of 8 t/ha in the wetter zones to a low of 1.5 t/ha in the drier zones. Winter wheat is grown in rotation with spring cereals and pulses where annual precipitation exceeds 450 mm; winter wheat-fallow prevails where annual precipitation is less than 330 mm. Tillage practices are designed to maximize infiltration and retention of water through soil surface and crop residue management. Because of the combination of winter precipitation, steep topography, and winter wheat cropping, much of the region is subject to a severe water erosion hazard, accentuated by freeze-thaw cycles that increase surface runoff and weaken the soil structure. Wind erosion is a major problem in the drier zones, where cover is less and soils are higher in sand. Residue management, primarily through reduced tillage and no-till systems, is the first defense against both wind and water erosion, but yields often are higher with conventional intensive ti llage. Factors that limit yields with conservation farming include weed and disease problems and th e lack of suitable tillage and seeding equipment. Conservation strategies must shift from relying on traditional tillage methods to development of complete no-till systems. Spring cropping as a replacement for winter wheat also needs to be investigated. In some cases, tillage for water conservation must be made compatible with tillage for erosion control.

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Influence of Soil Type and Depth of Planting on Downy Brome Seed

Weed Science ◽

10.1017/s0043174500048347 ◽

1971 ◽

Vol 19 (1) ◽

pp. 82-86 ◽

Cited By ~ 33

Author(s):

G. A. Wicks ◽

O. C. Burnside ◽

C. R. Fenster

Keyword(s):

Triticum Aestivum ◽

Winter Wheat ◽

Soil Type ◽

Bromus Tectorum ◽

Seedling Emergence ◽

Cropping System ◽

Soil Surface ◽

Downy Brome ◽

Moldboard Plow

Downy brome (Bromus tectorumL.) seedling emergence was greatest from soil depths of 1 inch or less, but occasionally seedlings emerged from depths of 4 inches. Downy brome seed covered by soil germinated more rapidly than those seed on the soil surface. More downy brome seedlings emerged, and from greater depths, from coarse-textured soils than fine-textured soils when moisture was not limiting. Soil type did not influence longevity of downy brome seed buried in the soil. Most (98%) 8-month-old downy brome seed buried 8 inches in the soil germinated but did not emerge in 1 year; and none remained viable in the soil after 5 years. The moldboard plow was more effective in reducing downy brome populations than a sweep plow or one-way disk in a continuous winter wheat (Triticum aestivumL.) cropping system.

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Influence of Soil Background on Spectral Reflectance of Winter Wheat Crop Canopy

Remote Sensing ◽

10.3390/rs11161932 ◽

2019 ◽

Vol 11 (16) ◽

pp. 1932 ◽

Cited By ~ 5

Author(s):

Elena Prudnikova ◽

Igor Savin ◽

Gretelerika Vindeker ◽

Praskovia Grubina ◽

Ekaterina Shishkonakova ◽

...

Keyword(s):

Winter Wheat ◽

Soil Type ◽

Spectral Reflectance ◽

Vegetation Index ◽

Vegetation Indices ◽

Soil Surface ◽

Wheat Crop ◽

Crop Canopy ◽

Winter Wheat Crop ◽

Type Factor

The spectral reflectance of crop canopy is a spectral mixture, which includes soil background as one of the components. However, as soil is characterized by substantial spatial variability and temporal dynamics, its contribution to the spectral reflectance of crops will also vary. The aim of the research was to determine the impact of soil background on spectral reflectance of crop canopy in visible and near-infrared parts of the spectrum at different stages of crop development and how the soil type factor and the dynamics of soil surface affect vegetation indices calculated for crop assessment. The study was conducted on three test plots with winter wheat located in the Tula region of Russia and occupied by three contrasting types of soil. During field trips, information was collected on the spectral reflectance of winter wheat crop canopy, winter wheat leaves, weeds and open soil surface for three phenological phases (tillering, shooting stage, milky ripeness). The assessment of the soil contribution to the spectral reflectance of winter wheat crop canopy was based on a linear spectral mixture model constructed from field data. This showed that the soil background effect is most pronounced in the regions of 350–500 nm and 620–690 nm. In the shooting stage, the contribution of the soil prevails in the 620–690 nm range of the spectrum and the phase of milky ripeness in the region of 350–500 nm. The minimum contribution at all stages of winter wheat development was observed at wavelengths longer than 750 nm. The degree of soil influence varies with soil type. Analysis of variance showed that normalized difference vegetation index (NDVI) was least affected by soil type factor, the influence of which was about 30%–50%, depending on the stage of winter wheat development. The influence of soil type on soil-adjusted vegetation index (SAVI) and enhanced vegetation index (EVI2) was approximately equal and varied from 60% (shooting phase) to 80% (tillering phase). According to the discriminant analysis, the ability of vegetation indices calculated for winter wheat crop canopy to distinguish between winter wheat crops growing on different soil types changed from the classification accuracy of 94.1% (EVI2) in the tillering stage to 75% (EVI2 and SAVI) in the shooting stage to 82.6% in the milky ripeness stage (EVI2, SAVI, NDVI). The range of the sensitivity of the vegetation indices to the soil background depended on soil type. The indices showed the greatest sensitivity on gray forest soil when the wheat was in the phase of milky ripeness, and on leached chernozem when the wheat was in the tillering phase. The observed patterns can be used to develop vegetation indices, invariant to second-type soil variations caused by soil type factor, which can be applied for the remote assessment of the state of winter wheat crops.

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Control of Armyworm on Heading Wheat with Bacillus Thuringiensis Products and Baculoviruses, 1994

Arthropod Management Tests ◽

10.1093/amt/21.1.318a ◽

1996 ◽

Vol 21 (1) ◽

pp. 318-319

Author(s):

S. Y. Young ◽

D. C. Steinkraus

Keyword(s):

Bacillus Thuringiensis ◽

Winter Wheat ◽

Adult Emergence ◽

Soil Surface ◽

Pseudaletia Unipuncta ◽

Pinto Bean ◽

Two Samples ◽

Anagrapha Falcifera

Abstract All applications were made on 26 Apr to ‘Wakefield’ winter wheat drilled on 6 inch row spacings on heading wheat in Lonoke Co., AR. A bicycle-type CO2 sprayer with a 12 ft boom equipped with TX-4 hollowcone nozzles on a 20-inch spacing, calibrated to deliver 10.5 gal/acre at 40 psi, was used for all treatments. Plots were 12 X 50 ft separated by 6 ft borders, arranged in a RCB design with 4 replications. A spreader sticker (CS-7) was added at a concentration of 1 ml/gal. The application was made late in the afternoon in a moderate breeze. No rainfall occurred during the test. Six Bacillus thuringiensis products and 3 viruses [Anagrapha falcifera NPV (AfNPV), Pseudaletia unipuncta NPV (AWNPV) and P. unipuncta GV (AWGV) were tested. Larval precounts made from the perimeter of the plots prior to the application showed a mean of 14.9 larvae per ft2. Post application larval counts were made at 4 and 7 DAT. Two samples per plot, each 3 ft in length and 12 inches in width, were taken by searching the soil surface, debris, and base of plants for larvae. Just prior to the search, the plants were jostled so that larvae on plants would fall to the ground. Yields were not taken. Larvae were collected from control and virus plots at 4 and 7 DAT. Larvae (25 per replicate) were individually placed in 1 oz plastic cups half-filled with pinto bean diet and held until death or adult emergence. Data from counts and collections were analyzed by ANOVA.

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OVERWINTERING OF CERTAIN CEREAL PATHOGENS IN ALBERTA

Canadian Journal of Research ◽

10.1139/cjr37c-041 ◽

1937 ◽

Vol 15c (12) ◽

pp. 547-559 ◽

Cited By ~ 6

Author(s):

W. R. Foster ◽

A. W. Henry

Keyword(s):

Winter Wheat ◽

Fusarium Culmorum ◽

Soil Surface ◽

Freezing And Thawing ◽

Tilletia Caries ◽

Helminthosporium Sativum ◽

Favorable Conditions ◽

Germ Tubes ◽

Continuous Freezing ◽

Hardened Condition

Helminthosporium sativum, Fusarium culmorum, Ophiobolus graminis, Leptosphaeria herpotrichoides, Wojnowicia graminis, Erysiphe graminis, Tilletia caries, and Tilletia foetens readily overwinter under natural conditions at Edmonton, Alberta, Canada. The first five of these overwinter at Edmonton in both spore and vegetative stages and are highly resistant to cold. Even in a non-hardened condition several of them survived severe frost. Young germ tubes of H. sativum for instance continued growth after being frozen solid overnight. Fresh agar cultures of H. sativum, F. culmorum and O. graminis grew vigorously after exposure to sub-zero temperatures. Agar cultures of H. sativum and F. culmorum were viable after a 17-day exposure to temperatures ranging from about 0° F. to —50° F.Conidia of H. sativum proved less resistant to freezing and thawing than to continuous freezing. They survived longer than conidia of F. culmorum and F. graminearum. Mycelia of all foot-rot fungi grown on sterilized barley seeds were viable in one case after three months of continuous freezing, and in another after 40 alternate freezings and thawings. H. sativum and F. culmorum growing in soil survived 61 alternate freezings and thawings.H. sativum, F. culmorum and L. herpotrichoides, retained their viability more readily on the soil surface than when buried at depths of from 2 to 12 in. Well aerated soil seemed to favor the survival of H. sativum, although other factors besides aeration probably are involved. Strains of H. sativum from high latitudes were not better adapted to low temperatures than strains from lower latitudes.The bunt fungi, T. caries and T. foetens, are shown to be capable of overwintering at Edmonton in the form of mycelia in winter wheat. Infection of winter wheat from soil-borne spores may occur in western Canada, but in these experiments soil-borne spores did not survive to infect wheat in the spring.Erysiphe graminis overwinters in the perithecial stage at Edmonton. In the studies made, ascospores were differentiated in the spring, when favorable conditions prevailed and before the first infections of winter wheat were observed.

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Fertilizer Placement Affects Jointed Goatgrass (Aegilops cylindrica) Competition In Winter Wheat (Triticum aestivum)

Weed Technology ◽

10.1017/s0890037x00041889 ◽

1999 ◽

Vol 13 (2) ◽

pp. 374-377 ◽

Cited By ~ 24

Author(s):

Abdel O. Mesbah ◽

Stephen D. Miller

Keyword(s):

Winter Wheat ◽

Seed Weight ◽

Wheat Yield ◽

Soil Surface ◽

Fertilizer Placement ◽

Aegilops Cylindrica ◽

Plant Seeds ◽

Placement Method ◽

Jointed Goatgrass ◽

Injection Methods

A 3-yr study was conducted in eastern Wyoming from 1995 to 1997 to evaluate the effect of fertilizer placement on jointed goatgrass competitiveness with winter wheat. Fertilizer placement methods consisted of applying 45 kg/ha of nitrogen (50% as urea and 50% as ammonium nitrate) in a deep band 5 cm below and 2.5 cm to the side of the wheat row, broadcasting on the soil surface, or injecting fertilizer by spoke wheel 10 cm deep and 5 cm to the side of the wheat row. Neither fertilizer placement nor jointed goatgrass presence affected winter wheat stand. Wheat yield reductions from jointed goatgrass competition were 7 and 10% higher with the broadcast than deep-band or spoke-wheel injection methods, respectively. Wheat spikes/plant, seeds/spike, 200-seed weight, and plant height were not influenced by fertilizer placement; however, the presence of 35 jointed goatgrass plants/m2reduced spikes/plant 21%, seeds/spike 12%, and 200-seed weight 6%. Jointed goatgrass populations were not influenced by fertilizer placement method; however, the number of spikes/plant was reduced 8 and 10%, joints/spike 3%, and biomass 15 and 21% by deep band or spoke wheel fertilizer placement.

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Quantifying the Effects of Wheat Residue on Severity of Stagonospora nodorum Blotch and Yield in Winter Wheat

Phytopathology ◽

10.1094/phyto-03-15-0080-r ◽

2015 ◽

Vol 105 (11) ◽

pp. 1417-1426 ◽

Cited By ~ 9

Author(s):

L. K. Mehra ◽

C. Cowger ◽

R. Weisz ◽

P. S. Ojiambo

Keyword(s):

North Carolina ◽

Winter Wheat ◽

Disease Severity ◽

Block Design ◽

Soil Surface ◽

Kernel Weight ◽

Stagonospora Nodorum ◽

Wheat Crop ◽

Stagonospora Nodorum Blotch ◽

Initial Inoculum

Stagonospora nodorum blotch (SNB), caused by the fungus Parastagonospora nodorum, is a major disease of wheat (Triticum aestivum). Residue from a previously infected wheat crop can be an important source of initial inoculum, but the effects of infected residue on disease severity and yield have not previously been quantified. Experiments were conducted in Raleigh and Salisbury, North Carolina, in 2012, 2013, and 2014 using the moderately susceptible winter wheat cultivar DG Shirley. In 2014, the highly susceptible cultivar DG 9012 was added to the experiment and the study was conducted at an additional site in Tyner, North Carolina. Four (2012) or six (2013 and 2014) wheat residue treatments were applied in the field in a randomized complete block design with five replicates. Treatments in 2012 were 0, 30, 60, and 90% residue coverage of the soil surface, while 10 and 20% residue treatments were added in 2013 and 2014. Across site-years, disease severity ranged from 0 to 50% and increased nonlinearly (P < 0.05) as residue level increased, with a rapid rise to an upper limit and showing little change in severity above 20 to 30% soil surface coverage. Residue coverage had a significant (P < 0.05) effect on disease severity in all site-years. The effect of residue coverage on yield was only significant (P < 0.05) for DG Shirley at Raleigh and Salisbury in 2012 and for DG 9012 at Salisbury in 2014. Similarly, residue coverage significantly (P < 0.05) affected thousand-kernel weight only of DG 9012 in 2014 at Raleigh and Salisbury. Our results showed that when wheat residue was sparse, small additions to residue density produced greater increases in SNB than when residue was abundant. SNB only led to effects on yield and test weight in the most disease-conducive environments, suggesting that the economic threshold for the disease may be higher than previously assumed and warrants review.

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