Wheat Rows Research Articles

Intercropping wheat and barley with N-fixing legume species: a method for improving ground cover, N-use efficiency and productivity in low input systems

SummaryTwo cereal cropping systems are described which, through the introduction of a leguminous intercrop, increased productivity, nitrogen output and ground cover of the systems in the absence of added nitrogen fertilizer. Nitrogen-fixing legumes were cultivated between rows of wheat or barley grown at low levels of soil nitrogen, and mostly under rainfed conditions, in Mexico between 1989 and 1992. None of the legumes tested reduced yields of the cereal crop in comparison to controls where cereal yields were in the range of 1–4 t/ha, while the extra total biomass from legumes in some cases more than doubled productivity. Different legume crops were tested to demonstrate the adaptability of the system to the varying needs of farmers. The intercropped legumes achieved dry biomass yields as high as 6·5 t/ha in the case of a sequentially cropped forage crop of hairy vetch, or 1·4 t/ha of dry beans plus 3·5 t/ha of green residue in the case of Vicia faba. Total biomass in the intercropped situation gave land equivalent ratios as high as 1·54. Light measurements inside the crop canopies indicated that the intercropped systems intercepted a higher proportion of the incident solar radiation than the cereal monocrop, presumably accounting for the large differences in total biomass produced. In addition, with leaf nitrogen levels of 3·8%, it is assumed that the intercropped legumes fixed considerably more nitrogen than was removed by the wheat crop. The potential of the system to stabilize erodible soils by increasing ground cover as well as by raising inputs of soil organic matteris discussed.

Net Returns from Italian Ryegrass (Lolium multiflorum) Control in Winter Wheat (Triticum aestivum)

In field experiments at three locations, wheat row spacing, seeding rate, and herbicide treatment affected Italian ryegrass control, wheat yield, dockage in the grain, and net returns. Diclofop at 560 or 840 g ai/ha controlled Italian ryegrass better than chlorsulfuron at 18 or 26 g ai/ha. Net returns were increased at all locations by diclofop POST at either rate and at two locations by chlorsulfuron PRE at either rate. Although increasing the wheat seeding rate reduced dockage at two of three locations, net returns were maximized by herbicide application alone without increased seeding rates or reduced row spacing.

Characterization and Pathogenicity of a New Anastomosis Subgroup AG-2-3 of Rhizoctonia solani Kuehn Isolated from Leaves of Soybean.

During July to August in 1992, a unusual foliar blight disease was observed on soybean plants intercropped between rows of winter wheat in an upland field converted from a paddy field at Tohoku National Agricultural Experiment Station in Morioka, northern part of Japan. The symptoms appeared as primary lesions consisting of small, circular necrotic spots, 1-mm or less than 1-mm in diameter, followed by secondary lesions showing circular to irregularly-shaped and large-sized areas of necrosis around the primary lesions under humid conditions. All the isolates of Rhizoctonia solani Kühn consistently recovered from leaves with the primary and secondary lesions (hereinafter referred to as leaf spot isolates) formed anastomoses in a high frequency (>75%) with the tester isolates of the anastomosis subgroup AG-2-1 but in a low frequency (<16%) with those of the AG-2-2 IIIB and IV and anastomosis group AG-BI. Among the 66 leaf spot isolates, 64 were auxotrophic for thiamine, whereas the isolates of the AG-2-1 were autotrophic for thiamine. The remaining 2 isolates could not grow even in the presence of thiamine. Culture appearance and optimum growth temperature of the leaf spot isolates were similar to those of the AG-2-1 rather than to those of the AG-2-2 IIIB and IV subgroup. Inoculation tests revealed that the leaf spot isolates were highly pathogenic to soybean, adzuki bean and kidney bean and caused severe pre-emergence and post-emergence damping-off, but were not pathogenic to rape and radish. The isolates caused foliar blight on soybean. These results indicated that most of the leaf spot isolates of AG-2 from soybean did not fit to either the AG-2-1 or AG-2-2 subgroup. Hence, we assigned these isolates to a new subgroup 3 in AG-2 (designated as AG-2-3).

Net Returns from Cheat (Bromus secalinus) Control in Winter Wheat (Triticum aestivum)

In field experiments, wheat row spacing, seeding rate, and herbicide treatment affected cheat seed content of harvested wheat, wheat yield, and net returns. No individual practice or combination of practices consistently increased net returns from cheat-infested wheat. Net returns frequently were increased and never decreased by applying metribuzin at 420 g ha−1 or chlorsulfuron + metsulfuron at 21.9 + 4.4 g ha−1 or by increasing the seeding rate compared to baseline inputs. The data indicate that herbicide rates should not be reduced when row spacing is decreased and/or seeding rates increased.

Determination of root distribution of wheat by auger sampling

Although the auger method has been reported to be simple and superior to other methods of determination of roots, a standard procedure of determining roots with the same is lacking. In a bid to standardize the auger method for studying wheat root distribution; we sampled roots with 5, 7.5 and 10 cm ID augers on the row and midway between rows down to 180 cm. The suitability of a sampling scheme was adjudged from bias between observed and actual root length densities (RLD). The actual density in a layer was obtained by integrating the equation fitted to the average of root density data horizontally between 0 and 11 cm, because for 22 cm apart rows of wheat the representative half of the unit soil strip was 11 cm from the row; and assumed actual RLD was the average of horizontal distribution of RLD in a particular layer. Single site sampling on the row or between rows gave the maximum bias. Average of two sites viz. on the row and midway between rows with 10 cm ID auger and 7.5 cm ID auger or at three sites with 5 cm ID auger (additional site midway between the earlier two) gave the best estimates in that order.

畑作における麦類の自生作物化と作付体系に関する研究 ＩＶ 麦種交互作の作付体系，作業体系，自生化対策としての事例分析

The objectives of this experiment are to clarify the relation between the growth of volunteer wheat plants and the cultivation methods under an alternating cropping system between barley and wheat.In the fields where left in fallow or planted with buckwheat during the summer following the wheat harvest using a head-feeding combine, a great number of volunteer wheat plants had grown in the barley fields. This was observed, also, in the fields where upland rice or peanut were planted in the inter-row spaces between the wheat rows. The fields which were left in fallow or planted with buckwheat during the summer following the wheat harvest using a conventional combine harvester showed few volunteer wheat. Almost no volunteer wheat plants grew in fields which were plow-tilled followed rotary-tilling and where left in fallow after flooding the fields during the summer.As a result of pot test, flooding the wheat grain for 5-7 days was effective in controlling volunteer wheat plants.

Effect of Early Season Powdery Mildew on Development, Survival, and Yield Contribution of Tillers of Winter Wheat

The formation, survival, and development of primary and secondary tillers of winter wheat (Triticum aestivum) are influenced by stresses the plant encounters during its growth. Three and two cultivars of winter wheat were planted near Clayton, North Carolina, in 1989 and 1990, respectively. Levels of powdery mildew (Blumeria graminis f. sp. tritici) were established by triadimenol seed treatment and presence or absence of rows of susceptible wheat inoculated with powdery mildew. Presence of primary and secondary tillers was determined four times during the growing season, and the contribution of each tiller to yield was assessed at harvest (...)

Intercropping Ethiopian Trifolium Species with Wheat

SUMMARYTrials were conducted in 1987 and 1988 to test methods of intercropping annual Ethiopian clovers, Trifolium spp, with wheat. Several different clover varieties, sowing methods, plant spacings, planting dates and rates of phosphorus application were compared. Planting in single or double alternative rows 20 cm apart did not affect wheat grain and straw yield but broadcast sowing of Trifolium in wheat rows 20 cm apart reduced wheat yield. The Trifolium species used significantly affected legume yield. Phosphorus fertilizer increased yield significantly, especially that of the legume component. The trials indicated that the intercropping of Ethiopian clovers in wheat has potential under African highland conditions.Siembra simultanea de trigo/ Trifolium en Etiopía

PRODUCTION POTENTIAL AND ECONOMICS OF WHEAT AND MUSTARD IN SOLE MIXED AND INTERCROPPING SYSTEMS

A field experiment was conduced at Cropping Systems Research Centre, Gujarat Agricultural University, Navsari during 1979-1980 to 1981-1982. Recommended seed rates of two crops were mixed in different ratios of wheat and mustard (50:50, 66.7:33.3, 75:25 and 83.3:16.7 per cent) and wheat rows alternated with different number of mustard rows (1:1, 3:2, 6:2 and 10:2) were compared with sole crops of wheat and mustard. The highest wheat equivalent (20.8 q ha¹) LER (1.59) and gross retums (6243 Rs/ha) were obtained when wheat and mustard seeds were mixed in ratio of 75:25 per cent which was similar to alternate rows (10:2 ratio) Thus a lower population of mustard in wheat either mixed or grown in rows gave the maximum profit.

Radar detection of a dew event in wheat

Radar backscatter measurements of wheat were made during two closely spaced nights: one with dew and the other without. Concurrent plant and soil moisture data were also obtained. The ability to detect the dew event was investigated for various radar frequencies, polarizations, incidence angles, and row orientations. The best detection of dew against the background of changing internal plant moisture or soil moisture was found with C band, HH polarization, incidence angles of 20° or less, and view direction parallel to the wheat rows.

Influence of wheat leaf position on leaf rust severity

The relation between flag leaf position and leaf rust severity was investigated in field experiments. Different leaf angles were obtained by attaching ends of flag leaves to strings stretched at different heights along wheat rows. Leaves with angles between lamina and stem of 0° and 45° were significantly less diseased than leaves with horizontal and pendulous positions. In the experiment with seedlings, spore settling and uredia number were significantly lower on erect than on horizontal leaves. The influence of wheat leaf position changes on leaf rust severity was discussed. It has been suggested that breeding of wheat cultivars with erect leaves can improve their resistance to airborne pathogens.

Mechanized relay‐cropping in an irrigated red‐brown earth in south‐eastern Australia

Abstract. Machinery was designed specifically for relay‐cropping on permanent raised beds (150 mm high and 1.5 m wide) in northern Victoria. This machinery enabled maize (Zea mays) to be successfully sown at 2, 4 and 5 weeks before harvest, and 1 day after harvest (Control), of wheat (Triticum aestivum). The sowing equipment consisted of a four‐row cultivator, behind which were four precision seeders. The wheels (250 mm in diameter) were spaced at 1.5 m to track along the base of the furrows. In one pass on each bed, the sowing equipment tilled two strips (each 50 mm wide, 30 mm deep and 50 mm from the outer row of wheat) and sowed maize, with little damage to the wheat crop. We extended the axle of the trailed harvester so that the wheels (250 mm in diameter) were 3 m apart, and moved the drawbar 300 mm to one side so that all wheels ran along the base of the furrows. There were no significant differences between treatments in yield (mean 2.9 t ha‐1) of dryland wheat, in final emergence percentage (mean 89%) or in early growth of irrigated maize. The maize yielded significantly less grain in the treatment sown at 5 weeks (9.6 t ha‐1), but not 2 or 4 weeks (mean 10.6 t ha‐1) before the wheat was harvested, than in the Control (10.8 t ha‐1). The wheat and maize yielded more grain than those grown traditionally as sole crops in northern Victoria.

Effect of ridge planting and N-application methods on wheat grown in somewhat poorly drained soils

Wheat is grown in many areas of the world with environmental conditions similar to those in southeastern Kansas. Rainfall averages 100 cm year −1 and the subsoil has a high clay content, which probably impedes percolation and drainage. Much of the rainfall occurs over winter when the wheat is transpiring at low rates. Thus, saturated soil-moisture conditions may develop and persist for extended periods. This study was designed as two experiments to examine the response of wheat ( Triticum aestivum L.) planted on ridges to facilitate drainage as compared with other tillage systems. In two site-years for Experiment 1, ridge:skipfurrow (wheat planted 25-cm apart, i.e., paired rows straddling small ridges that are on 76-cm centers) resulted in 15–30% higher yields than either non-ridged reduced or no-tillage systems. Intermediate yields were obtained with ridge: no-skip (one row of wheat planted in the furrows as well as two rows on each ridge). In two site-years for Experiment 2, ridge: no-skip resulted in higher yields than either reduced or conventional tillage, with intermediate yields from ridge: skip-furrow. Rainfall patterns may account for the differences in ridge system responses. Gravimetric soil moisture was lower in ridge systems than in “flat” reduced, conventional, or no-tillage systems. Yield tended to be greater with dribble than broadcast applications of urea-ammonium nitrate (UAN) solution as a spring topdress, especially for ‘Arkan’ variety wheat. Grain N content was 3–8% higher with dribble than broadcast UAN applications.

Inactivation of Metribuzin in Winter Wheat by Activated Carbon

Preemergence and postemergence application of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one] at 0.6 and 1.1 kg ai/ha controlled downy brome (Bromus tectorumL. ♯ BROTE) in winter wheat (Triticum aestivumL. ‘McDermid’) but caused considerable injury without the use of activated carbon over the seeded row. Activated carbon applied in 5-cm bands over the seeded row at 84, 167, and 336 kg/ha protected winter wheat at Pendleton on a silt loam soil. On a sandy loam soil, only a 336 kg/ha rate provided protection from metribuzin. Metribuzin toxicity to winter wheat was more difficult to neutralize when applied preemergence. Downy brome control was not reduced by carbon applied over the wheat row. The best treatment in this study was carbon at 336 kg/ha applied preemergence over the row followed by metribuzin at 0.6 or 1.1 kg/ha postemergence. A 10-week delay between preemergence carbon banding and postemergence metribuzin protected winter wheat from chemical injury.

Wheat Performance Using No‐Tillage with Controlled Wheel Traffic on a Clay Soil1

AbstractWheat (Triticum aestivum L.) is frequently grown in rotation with summer annual crops. These crops are usually grown in widely spaced rows that can easily adapt to controlled‐traffic management, but high soil strengths prevent crop establishment into controlled‐traffic lanes, eliminating one or more rows of wheat. Wheat can compensate (within limits) for lost cropping area, but the effect of no‐tillage culture with controlled traffic is not known. We conducted this study to compare two tillage systems, conventional and no‐tillage with controlled traffic, on grain yield and yield components of wheat. It was conducted over a 3‐year period on an Austin silty clay (fine‐silty, carbonatic, thermic Entic Haplustolls). The no‐tillage treatment confined all wheel‐induced compaction to controlled traffic zones at 2‐m intervals. Crop residues were destroyed completely by repeated tillage and wheel traffic occurred randomly under the conventional tillage treatment. Hard red winter wheat (cv. Sturdy) was grown in rotation with row crops that were subjected to the same tillage and wheel traffic practices. Rows were spaced 20 cm apart in each tillage system, but two rows were deleted in the traffic zones of the no‐tillage treatment, resulting in 20% less cropped area. Plants on rows adjacent to the controlled‐traffic zones compensated for the absence of wheat within the traffic zones during years of adequate precipitation (1981 and 1983) by producing more tillers and grain than plants in rows within the no‐tillage treatment and those grown under conventional tillage. Drought in 1982 significantly lowered tillering and grain yields under no‐tillage. The study established that wheat can be grown using no‐tillage with controlled traffic. Wheat should be grown with no‐tillage controlled‐traffic technology where drought is minimized or as a component of a total management system where yield increases from alternative crops and/or lower production costs are primary issues.

Optimum Spacing of Preplant Bands of N and P Fertilizer for Winter Wheat1

AbstractIn previous field studies a 46 cm spacing of preplant bands of N and P fertilizer has caused uneven growth of winter wheat (Triticum aestivumL.), with better growth immediately atop the preplant bands. Narrower spacing of fertilizer bands could improve plant growth uniformity and grain production by winter wheat. The objective of this study was to evaluate N‐P fertilizer band spacing on wheat growth and grain yield. The effect of P band spacing on fertilizer P uptake from a preplant band was studied in the greenhouse with winter wheat. Phosphorus uptake from the fertilizer band was influenced by the lateral distance from the wheat row to the P band at 33 days after planting. By 40 days after planting, however, uptake of fertilizer P was the same from bands placed 0, 10, and 20 cm from the wheat row, while P uptake was significantly less from the band placed 30 cm from the row, apparently due to another row of wheat shielding the fertilizer P from uptake. Field studies consisting of combinations of spacings of preplant bands (25, 38, and 50 cm) and rates of P fertilizer (0,6, 12, and 24 kg/ha), all with 84 kg N/ha, were conducted on winter wheat. All treatments were deep‐placed preplant band applications of liquid ammonium polyphosphate (APP, 10‐15‐0) and anhydrous ammonia (82‐0‐0). Wheat was drilled perpendicular to the direction of the preplant band application. Early season growth of winter wheat increased with increasing P rate and by decreasing the distance between preplant bands. Final grain yield, however, was influenced only by P rate, and not by P band spacing. Plant samples taken from 12.5 cm of drill row centered over the band and 12.5 cm of drill row centered between preplant bands of each treatment indicated differences between those areas in dry matter production, P uptake, spike density, and grain yield due to P rate and band spacing. Thus, more uniform growth resulted from the closer band spacing of 38 and 25 cm which could result in higher grain yields under optimum wheat production conditions.

Chemical Control of Cereal Cyst-Nematode (Heterodera a Venae) On Wheat By a New Low-Volume Applicator

A new applicator, using microtubes, which allows the accurate placement in soil of very small volumes of nematicides or other liquids is described. When used to inject ethylene dibromide (EDB) in rows of wheat during sowing to control cereal cyst-nematode, the initial cost of the applicator and EDB was recovered from the increased yield from 2 ha. The reasons for the efficacy of the treatment and the non-phytotoxicity of EDB are unknown.

Relay Intercropping Soybeans into Winter Wheat and Spring Oats1

AbstractRelay intercropping of soybeans [Glycine max (L.) Merr.] into small grains might allow the two‐crops‐in‐1 year concept to be moved further northward in the U.S. Corn Belt. The small grain crops in such a system might also provide protection against soil erosion on sloping soils currently in conventional soybean production. The objective of this study was to compare monoculture oat (Avena saliva L.), wheat (Triticum aestivum L.), and soybean yields with soybeans relay intercropped into spring oats or winter wheat. Variables considered included small grain and soybean row widths, soybean planting date, and soybean cultivar. Field experiments were conducted on Typic Haploquoll and Typic Argiudoll soils in central Illinois.Interseeding soybeans into small grains did not affect small grain yields. In three of four environments tested, small grain yields in rows 41, 61, and 81‐cm wide averaged yields of 91, 72, and 58%, respectively, of small grains in 21‐cm row widths. In a fourth experiment, where winter wheat rows wider than 21‐cm were created by spring removal of intervening rows, yield reductions were greater than for those planted in wider rows. Monoculture soybeans produced significantly higher yields and taller plants than intercropped soybeans. Reduced growth of intercropped soybeans, especially in narrow rows, was associated with below normal precipitation during both years of experimentation. Soybeans intercropped between 41 and 61‐cm small grain rows yielded between 7 and 93% of monoculture soybeans grown in similar row widths. Soybeans aerially seeded into small grain stands failed to establish a stand, but soybeans conventionally placed in the soil produced acceptable stands. A short determinate soybean cultivar did not appear to withstand early season stress associated with intercropping as well as a tall indeterminate cultivar. In years with normal early season precipitation, successful relay intercropping of soybeans into small grains should be possible.

Protein and Lysine Contents of Endosperm and Bran of the Parents and Progenies of Crosses of Common Wheat1

Grain samples from parent and progeny rows of the common wheat (Triticum aestivum L.) crosses, ‘Nap Hal’/ ‘Atlas 66’ and Nap Hal/‘Super X’, were fractionated into their starchy endosperm and bran components to determine the within‐kernel site of their variation in protein and lysine concentration. Nap Hal and Atlas 66 are highprotein wheats. Nap Hal also has elevated grain lysine content. Super X has average protein and lysine content. Transgressive segregation existed both for high and low endosperm protein concentration among the F5 progeny rows of Nap Hal/Atlas 66. Low‐protein progeny rows had endosperm protein percentages that were 3 to 5 percentage points lower than the parental mean (19.5%). High‐protein progeny lines were 2 to 4 percentage points higher than the parental mean. Nap Hal and some of the progeny rows were 5 percentage points higher in bran protein content than Atlas 66. Endosperm and bran protein percentages of Nap Hal/Super X F4 progeny were within the parental range. Some progeny rows had endosperm and bran protein concentrations equal to those of Nap Hal. Variation among the progeny rows for endosperm and bran lysine (% of protein) concentrations was within the range of variability of the replicated parental rows. Variation for grain protein content among the progeny rows of both crosses was due to variation for both endosperm and bran protein content. Variation for grain lysine (% of sample) among the Nap Hal/Atlas 66 progeny rows was due primarily to variation in endosperm and bran protein content with endosperm and bran lysine (% of protein) being of lesser importance.

Yield Adjustment for Missing Units in Spring Wheat1

Plot rows of spring wheat (Triticum aestivum L.) having missing areas were studied to determine if an appropriate correction factor could be determined to adjust plot yields. Areas ranging from 0 to 240 cm (0 to 8 missing units or 50% of the area) were removed in one or two plot rows harvested subsequently for yield. Different genotypes, with diverse agronomic characteristics, were included in different years.Generally, no significant decrease in yield of the genotypes was detected until more than 60 cm (12.5%) of plot area was removed. Regression analyses were performed each year and indicated that the average slope (b) based on percent reduction in yield per missing unit (30 cm) was about 4.55%. The b values ranged from 3.7 to 5.0% reduction in yield per missing unit across genotypes and years. Satisfactory adjustments of yield, based on the average percent reduction (4.55%), were obtained if yield adjustment was ignored until more than 2 missing units (60 cm) occurred.