Wheat-soybean Double-crop System Research Articles

Effectiveness of direct application of top dressing with spent coffee grounds for soil improvement and weed control in wheat-soybean double cropping system

ABSTRACT With increasing annual global coffee consumption, the amount of spent coffee grounds (SCGs) increases. Direct application of SCGs in large agricultural fields can potentially improve soil and control weeds in an environmentally safe manner. However, except for composting, the use of SCGs during cropping has not been implemented thus far because of inhibitory effects on crop growth observed in pot-based studies. We evaluated the effect of a top dressing approach to direct SCG application on crop biomass, soil improvement, and weed control, through double cropping field experiments using wheat and soybean. The field experiments were conducted over six successive cropping seasons in an upland field converted from paddy, and crop and weed biomass as well as soil total carbon and nitrogen were investigated. To avoid growth inhibition, the SCGs were surface broadcasted after crop germination to mimic living mulch. The soil total carbon and nitrogen contents increased significantly under an SCG concentration of 5 kg m−2 or more, approximately 20 months after the first application, whereas SCG application did not significantly affect crop yield except for the first cropping of wheat. In addition, the 10 kg m−2 SCG application reduced the weed biomass by 50% or more during cropping, except for the wheat cropping in the second year. We concluded that top dressing with SCGs after crop germination is an efficient method for sustainable agricultural production, although further detailed studies of SCGs’ effect on the crop growth and soil characteristics are required.

Nematode populations as affected by residue and water management in a long-term wheat-soybean double-crop system in eastern Arkansas

Soybeans (Glycine max L.) are one of the major row crops in the United States, particularly in Arkansas. The soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is one of the most damaging pests that can cause major economic losses in soybeans. Little is known concerning the combined effects of tillage [conventional tillage (CT) and no tillage (NT)], water management (irrigation and non-irrigation), residue burning (burn and no burn), and wheat residue level (high and low) on nematodes. The objective of this study was to evaluate the effects of the combination of agronomic practices (tillage, water management, burning, and residue level) on natural nematode population densities and change over the growing season in a long-term wheat (Triticum aestivum L.)-soybean rotation on a silt-loam soil in Arkansas. A suite of 10 nematode genera were measured in the top 10 cm in July, August, and October in 2017 and 2018. Averaged across all other treatment factors, SCN egg concentration was 17.9 times greater at the end of the growing season in October than in July and August. The SCN second-stage juvenile (J2) population densities were 3.4 times greater in the CT-burn than in the CT-no-burn and NT-burn treatment combinations. In contrast to under CT, SCN J2 population densities were 3.8 times greater in the NT-no-burn than under the NT-burn treatment combinations. Lance, lesion, spiral, and stunt nematode population densities were also affected by various field treatment combinations. Traditional (i.e., tillage, residue burning, and irrigation) and alternative (i.e., non-tillage, no burning, and dryland) wheat-soybean management practices can influence nematode population densities even in non-problematic fields, thus potentially affecting long-term strategies to maximize soybean profitability.

Native earthworm population dominance after seven years of tillage, burning, and residue level management in a wheat-soybean, double-crop system

Earthworm density is often reduced in low organic matter soils that are intensively managed for row-crop production, but earthworms can serve as a sensitive bioindicator of response to residue management. This study relates earthworm density and community composition to residue management after seven years of consistent management practices in a wheat (Triticum aestivum L.)-soybean (Glycine max (L.) Merr.), double-crop system in the Lower Mississippi River Valley delta region of eastern Arkansas. Residue management practices included conventional tillage (CT) and no-tillage (NT), N fertilization to produce HIGH and LOW wheat residue levels, and BURN compared to unburned (NO BURN) wheat residue remaining on the soil surface. Total mean earthworm densities ranged from 271 to 508m−2 in the top 20cm across treatments. Both exotic Aporrectodea trapezoides (Dugès) and native Diplocardia sylvicola Gates adult earthworms were present with little difference in diversity among sampled communities; however, more than 65% of adults were D. sylvicola in all treatments. Native, total, or juvenile earthworm densities in different treatment combinations were correlated to different soil properties, including pH, electrical conductivity, and Mehlich-III-K, Ca Mg, S, Cu, and Mn concentrations. Residue level and burning influenced total, juvenile, and native earthworm densities differently in CT and NT. Tillage presumably influenced earthworm density through effects of residue placement at the surface (NT) or within the soil profile (CT). Earthworm densities were greatest in the BURN-HIGH treatment combination under NT, which contrasted with greatest densities in the NO BURN-HIGH which did not differ from the BURN-LOW treatment under CT. Native earthworms predominated with a common exotic species in a wheat-soybean double-crop system in Arkansas where earthworm densities were dependent on the interaction of tillage with burning and fertilization to influence wheat residue amount. Differences in earthworm abundances may serve as a bioindicator of long-term sustainability of common residue management practices in the highly agriculturally productive delta region in the Lower Mississippi River Valley.

Long-term Management Effects on Soil Properties and Yields in a Wheat-Soybean Double-Crop System in Eastern Arkansas

The sustainability of soil and water resources in regions of highly productive row-crop agriculture depends on long-term implications of agricultural management decisions. Residue management can strongly affect soil organic matter (SOM), soil C, and other near-surface physical and chemical properties in agricultural soils, especially in double-crop systems. The objective of this study was to determine the long-term trends in SOM, soil C and N, bulk density, pH, electrical conductivity, and Mehlich-3–extractable nutrients in the top 10 cm and yield as affected by alternative residue and water management practices in a wheat (Triticum aestivum L.)-soybean (Glycine max (L.) Merr.) double-crop production system. The field site resides on a loessial soil (fine silty, mixed, active, thermic Glossaquic Fraglossudalf) in the Lower Mississippi River Alluvial Valley of eastern Arkansas and has been consistently managed for 13 years between Fall 2001 and Fall 2014. Averaged across all other treatment factors, SOM content did not change (P > 0.05) between 6 and 13 years after conversion to alternative management practices under irrigation, whereas SOM content increased across time (P < 0.05) until approximately 9 years after initial conversion then decreased thereafter under dryland production. Soil C content generally increased, P content generally decreased, and N and Cu contents and soybean yields changed little across time because of irrigation. Across time, SOM and C contents decreased (P < 0.05) under residue burning but increased under nonburning. The results of this study indicate that irrigation management and residue burning were responsible for many of the largest differences in near-surface soil property trends across time. Understanding the long-term effects of alternative, compared with traditional, management practices is critical to developing sustainable agricultural practices in the mid-southern United States.

Long-term Residue Management Effects on Soil Respiration in a Wheat-Soybean Double-Crop System

One of the most significant contributors to the greenhouse effect is carbon dioxide (CO2) gas in the atmosphere. Soil respiration, the combined production of CO2 from soil, as a result of root and microorganism respiration, is the largest flux of CO2 from the terrestrial ecosystem to the atmosphere. Considering land use can greatly impact soil C storage and cycling, agricultural management practices can also greatly affect soil respiration and CO2 emissions. Therefore, the effects of long-term residue management (i.e., residue burning and nonburning, and conventional [CT] and no-tillage [NT]) and residue level (i.e., high and low) on soil respiration during the soybean [Glycine max (L.) Merr.] growing season were examined over 2 consecutive years (i.e., 2011 and 2012) in a wheat (Triticum aestivum L.)–soybean, double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta region of eastern Arkansas after more than 9 years of consistent management. Soil respiration rates from individual plots ranged from 0.53 to 40.7 and from 0.17 to 13.1 μmol CO2·m−2·s−1 throughout the 2011 and 2012 soybean growing seasons, respectively, and differed (P < 0.05) among treatment combinations on two and five of nine and 11 measurement dates in 2011 and 2012, respectively. Regardless of residue level, soil respiration was generally greater (P < 0.05) from CT than NT. Estimated season-long CO2 emissions were 10.2% less (18.5 Mg CO2·ha−1) from residue burning than from nonburning (20.6 Mg CO2·ha−1; P = 0.032). Averaged over years and all other field treatments, estimated season-long CO2 emissions were 15.5% greater from CT (21.0 Mg CO2·ha−1) than from NT (18.1 Mg CO2·ha−1; P = 0.020). Understanding long-term management effects on soil C losses, such as soil respiration, from common and widespread agricultural systems, such as the wheat-soybean, double-crop system, in eastern Arkansas can help improve policies for soil and environmental sustainability throughout the lower Mississippi River Delta region.

Residue Management Practice Effects on Soil Surface Properties in a Young Wheat-Soybean Double-Crop System

ABSTRACT Approximately 25% of the soybean [Glycine max (L.) Merr.] grown in the mid-South is produced in a wheat (Triticum aestivum L.)-soybean double-crop system. Pre-soybean field preparations often consist of removing wheat residue by burning followed by conventional tillage (CT). However, crop residue burning has serious negative environmental consequences and will likely be outlawed in the future. Therefore, the objective of this study was to evaluate the short-term effects of alternative wheat-residue management practices, tillage [no-tillage (NT) and CT], burning (burn and no burn), and wheat-residue level (low and high), on soil surface properties after two full cropping cycles in a wheat-soybean double-crop production system on two silt-loam Alfisols in east-central Arkansas. Soil bulk density increased over time, but the increase was unaffected by imposed treatments. Changes in soil pH and electrical conductivity (EC) were generally unaffected by tillage or burning, whereas soil EC increased by 7% under the high and decreased by 8% under the low wheat-residue level treatment at one location, but not the other. Mehlich-3-extractable Mg and Zn increased more and Na decreased less under NT than CT at one location or the other. Soil organic matter and total N and C also increased more under NT than CT at one location, but not the other. The results of this study indicate that, in a wheat-soybean double-crop production system in a relatively warm and wet environment, numerous soil properties can be improved more under NT than CT and more when crop residues are left unburned than when they are removed by burning. Extended use of alternative wheat-residue management practices that improve soil tilth will result in more sustainable agriculture and likely increase production.

Residue Management Practice Effects on Soybean Establishment and Growth in a Young Wheat-Soybean Double-Cropping System

ABSTRACT Double-cropping wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.] is popular throughout the mid-southern United States. To ensure an adequate stand, it is imperative that soybean be planted as soon as possible after wheat harvest due to an already shortened growing season following wheat. Typically, wheat residue is burned, and then conventional tillage (CT) is used to prepare a seedbed for soybean planting. However, residue burning has serious negative environmental consequences. The objective of this study was to examine effects of tillage [CT and no-tillage (NT)], residue burning (burn and no burn), and wheat-residue level (high and low) on soybean stand establishment, growth, and production over three cropping cycles at two locations on silt-loam Alfisols in eastern Arkansas. Soybean plant populations between 10 and 30 days after planting were higher (p < 0.02) under NT than CT in most year-location combinations, while most without wheat residue burning were equivalent to those with burning. Soybean plant populations were unaffected by N rate/wheat-residue level in most year-location combinations. Mid-season soybean leaf area index was higher (p < 0.03) under NT than CT for two of four year-location combinations. Soybean yields under NT were equivalent to yields under CT in all year-location combinations. Results indicate that the alternative pre-plant field preparation combination of no residue burning followed by NT can perform as well as the more traditional combination of burning followed by CT in the wheat-soybean double-crop system in the mid-southern United States.

Effects of cultivar maturity on growth and yield of double cropped soybean

Maintaining yield potential or reducing yield losses is very important for soybean [Glycine max (L.) Merr.] double cropping to be profitable. Our objectives were to study the effects of cultivar maturity on yield, yield components and to determine adaptation and yielding potential of 18 soybean cultivars (six cultivars in each of the maturity groups II, III and IV) in the eastern Mediterranean region of Turkey in 2000 and 2001. The experimental design was randomized complete block with three replications. Effects of maturity group (MG) on seed yield, yield components, and key phenological stages were significant. Cultivars in MG IV had significantly higher seed yield, plant height, lowest pod height and number of nodes/plant than cultivars in MG II and III. Among cultivars, the highest seed yield was obtained from KS4895 (MG IV) with 3.75 t/ha and the lowest was obtained from Dwight (MG II) with 1.18 t/ha. Except for the number of seeds/pod, all of the measured yield components and key phenological stages were significantly and positively correlated with seed yield. Based on the path analysis of the combined data, it was found that the number of seed/m2, the period from VE to R1 and from R1 to R7 had greatest positive direct effect on seed yield. The results of the current study showed that cultivars in MG IV were best adapted and best suited for a wheat-soybean double cropping system in the eastern Mediterrenean region of Turkey.

Yield Components as Indirect Selection Criteria for Late‐Planted Soybean Cultivars

Cultivar selection for late‐planted soybean [Glycine max (L.) Merr.] in the wheat–soybean doublecropping system is an important production problem. Top‐yielding cultivars for late plantings could be selected more efficiently by identification of yield components that indicate top yield, compared with the traditional combine‐harvested plot yield method. Our objective was to identify yield components that could be used as indirect selection criteria to identify top‐yielding cultivars for late planting dates. A 2‐yr study (1998 and 1999) with 26 cultivars was conducted at a mid‐July planting at Baton Rouge, LA (30° N, 90° W). A similar study involving 27 different cultivars was conducted for 1 yr at Los Oliveros, Santa Fe Province, Argentina (32°48′ S, 62° W), planted in early January 1999. Experimental designs were randomized complete blocks with four replications and one factor (cultivar). Data were obtained on combine‐harvested plot yield, seed m−2, seed size, seed per pod, pods m−2, pods per reproductive node, and reproductive node m−2. Across years, yields at Baton Rouge ranged from 1183 to 2992 kg ha−1, while yields in Argentina ranged from 1688 to 2809 kg ha−1. Yield at Baton Rouge increased with maturity group, whereas in Argentina there was no relationship between yield and maturity group. For both phenotypic and genotypic levels, selection for either seed m−2 or pods m−2 identified top‐yielding cultivars, although seed m−2 was more accurate.

Yield Components as Indirect Selection Criteria for Late-Planted Soybean Cultivars

Cultivar selection for late-planted soybean [Glycine max (L.) Merr.] in the wheat–soybean doublecropping system is an important production problem. Top-yielding cultivars for late plantings could be selected more efficiently by identification of yield components that indicate top yield, compared with the traditional combine-harvested plot yield method. Our objective was to identify yield components that could be used as indirect selection criteria to identify top-yielding cultivars for late planting dates. A 2-yr study (1998 and 1999) with 26 cultivars was conducted at a mid-July planting at Baton Rouge, LA (30° N, 90° W). A similar study involving 27 different cultivars was conducted for 1 yr at Los Oliveros, Santa Fe Province, Argentina (32°48′ S, 62° W), planted in early January 1999. Experimental designs were randomized complete blocks with four replications and one factor (cultivar). Data were obtained on combine-harvested plot yield, seed m−2, seed size, seed per pod, pods m−2, pods per reproductive node, and reproductive node m−2. Across years, yields at Baton Rouge ranged from 1183 to 2992 kg ha−1, while yields in Argentina ranged from 1688 to 2809 kg ha−1. Yield at Baton Rouge increased with maturity group, whereas in Argentina there was no relationship between yield and maturity group. For both phenotypic and genotypic levels, selection for either seed m−2 or pods m−2 identified top-yielding cultivars, although seed m−2 was more accurate.

Agronomic and economic performance of wheat and canola-based double-crop systems

AbstractDouble-cropping provides a method of diversifying the rotation, maximizing production, and increasing the profit potential of a cropping system. We assessed agronomic and economic performance of five alternative crops in comparison to the no-till wheat-soybean double-cropping system prevalent in the southern Corn Belt. Canola has shown potential as a profitable winter crop, but its effects on the subsequent crop in a no-till double-crop system required further study. Amaranth, buckwheat, sunflower, and pearl millet were planted after the harvest of canola or wheat, or after fallow. Alternative double-crop grain yield, production costs, and net returns were compared with those of double-crop soybean.Wheat yielded more than canola. Sunflower grain yields did not differ significantly after winter-crop treatments at any site. Yields of amaranth, buckwheat, soybean, and pearl millet differed after winter crops at some sites. At three study yield levels, net returns were positive and greatest for double-crop wheat-amaranth, canola-amaranth, wheat-sunflower, and canola-sunflower systems. All double-crop systems except canolapearl millet had positive net returns at median study yield levels. Low or negative net returns resulted from the combination of low yield and low price for some double crops. Canola was shown to be an economically feasible alternative to wheat in a doublecropping system for central and southern Missouri. Buckwheat and sunflower were shown to be agronomically and economically competitive alternatives to soybean following either canola or winter wheat, with buckwheat most valuable in late-season planting conditions.

Net Returns from No-Till Doublecrop Winter Wheat and Irrigated Soybean on a Clay Soil

Economic evaluation of agronomic production practices is required to determine their feasibility in cropping systems with two or more crops. Net returns from continuous double-cropped wheat (Triticum aestivum L.) and irrigated soybean [Glycine max (L.) Merr.] were calculated using data from plantings made in 1988, 1989, and 1990 near Stoneville, MS, on a Tunica clay (clayey over loamy, montmorillonitic, nonacid, thermic, Vertic Haplaquept) in tilled and no-till seedbeds in both burned and standing wheat stubble. Yield of soybean was not affected by stubble management or seedbed preparation. Yield of wheat was reduced in plantings made following soybean that was planted in standing wheat stubble in the first 2 yr of the study. Seedbed preparation for wheat planting had an inconsistent effect on wheat yield. Wheat yields declined as the study progressed. Combined net returns were greater from the burned stubble treatment in 2 of the 3 yr, and this was attributed to the higher net returns from wheat in this treatment. Combined net returns from the tilled seedbed treatment were similar to those from the no-till treatment in 1988 and 1989; in 1990, net returns from the tilled seedbed treatment were higher. These results indicate that highest combined net returns from a continuous wheat-soybean doublecrop system will be obtained when soybean is planted in burned wheat stubble. Low and declining wheat yields in this short-term study (confounded with year effects) indicate that continuous wheat-soybean doublecropping using no-till planting of wheat is not a viable management option. This conclusion has to be verified with longer-term research, however.

Yield and Net Returns from Monocrop Winter Wheat Systems and a Winter Wheat-Soybean Doublecrop System

Economic evaluation of agronomic production practices is required to determine the feasibility of inputs used in cropping systems with two or more crops. The objectives of this study were to determine the effect of preplant tillage and seedbed type on subsequent monocrop wheat (Triticum aestivum L.) seed yield and net returns, and compare the results with those from a wheat-soybean [Glycine max (L.) Merr.] doublecrop system (TRT 6). Net returns were calculated using data from plantings made for 4 yr on a Tunica clay (clayey over loamy, montmorillonitic, nonacid, thermic Vertic Haplaquept) near Stoneville, MS. Within the monocropped wheat treatments, preplant management inputs were : TRT 1-wheat planted flat following summer fallow ; TRT 2-wheat planted flat following a summer legume crop [Hemp sesbania, Sesbania exaltata (Raf.) Rydb. ex A.W. Hill] ; TRT 3-wheat planted flat following summer fallow and subsoiling ; TRT 4-wheat planted on 80-in.-wide beds following summer fallow ; TRT 5-wheat planted on 80-in.-wide beds following summer fallow and subsoiling ; and TRT 6-wheat-soybean doublecrop, where soybean was planted no-till in burned wheat straw and wheat was planted in harrowed (disk and/or spring-tooth) soybean stubble. Wheat yields from TRT 3 were among the highest each year, but net returns resulting from this treatment were among the highest in only 2 of the 4 yr. Combined net returns from TRT 6 were among the highest in all years, but they were positive in only 2 of the 4 yr and soybean yields averaged only 14.8 to 25.2 bu/acre. Net returns (losses in all 4 yr) resulting from TRT 2 were among the lowest each year because of the expense associated with establishing and incorporating the legume residue. These results indicate that monocropping of wheat, regardless of preplant management, is not a feasible replacement for winter wheat-soybean doublecropping in a nonirrigated environ on clay soil, even though wheat yields were higher in the monocrop treatments in most years Expenses associated with summer fallow maintenance for monocropped winter wheat were not offset by sufficiently higher yields.

Burning, tillage and herbicide effects on the soil microflora in a wheat-soybean double-crop system

As sustainable crop management systems are developed, an assessement of the effects of these practices on the soil microflora is essential to ensure maximum productivity. A 3-year field study was established to determine the effects of crop residue burning, no-till management and four preemergence herbicides on soil microorganisms. Numbers of actinomycetes, algae, bacteria, fungi and nitrifiers were evaluated during the soybean [ Glycine max (L.) Merrill] growing season in a wheat ( Triticum aestivum L.)-soybean double-cropping system. Residue burning and tillage had no effect on numbers of bacteria and nitrifiers. Non-disturbed (non-burned or no-till) plots had greater numbers of actinomycetes, algae and fungi 7 days after herbicide application each year, but the increases generally did not persist through the season. Herbicide application had no effect on microbial numbers. This is particularly important with recent increased emphasis on protection of soil and water resources from pesticide contamination. As new management systems are developed, their effects on biological properties must be carefully assessed, since the soil microflora play such a vital role.

Effect of Disk Harrowing on Subsequent Emergence of Hessian fly (Diptera: Cecidomyiidae) Adults from Wheat Stubble

Conical cloth traps were used to compare emergence of Hessian fly, Mayetiola destructor (Say), adults from three land preparation regimes: 1) wheat stubble disked; 2) stubble not disked, but burned; 3) stubble neither disked nor burned (control). Burning had no effect on emergence in the one experiment in which it was tested. Mean emergence in disked plots was approx. 60% less than in control plots. However, this difference was significant in only one of four experiments. Implications for Hessian fly management within a wheat-soybean double-cropping system are discussed.

Impact of Volunteer Wheat on Wheat Insects in a Wheat-Soybean Double-crop System

The impact of the presence of noncompetitive levels of volunteer wheat, Triticum aestivum L. em Thell, in a summer crop on insect infestations in a subsequent crop of winter wheat was examined in a wheat-soybean, Glycine max (L.) Merrill, double-crop system in Georgia. The only insect collected from volunteer plants in large numbers was the Hessian fly, Mayetiola destructor (Say), although small numbers of thrips and aphids also were collected. Hessian fly immatures were not detected in volunteer plants before mid-August and were not prevalent until September. Hessian fly infestations were greater in volunteer plants that were present throughout the summer than in plants which were present only after mid-August. The presence of volunteer wheat in the soybean crop had little effect on Hessian fly infestations in the following crop of winter wheat. Tillage probably disrupted Hessian fly activity and prevented the carryover of insects from volunteer plants to the subsequent wheat crop. Delaying planting of winter wheat by about one month greatly reduced fall infestations on the Hessian fly regardless of the occurrence of volunteer wheat in the previous summer crop.