Soybean Row Research Articles

Evaluation of maize-soybean intercropping systems and fertilizer rates on maize grain yield using competitive indices

Field trials were conducted in savanna ecologies of Nigeria during the 2015 and 2016 seasons using maize (PVA8) and soybean (TGX 1448-2E) intercropping systems with different fertilizer rates to evaluate the yield of maize and assess the best intercropping system for resource management. Single plant stands and two plants/stand and 2 arrangements of rows (one row on a ridge and two rows on a ridge) were used to impose maize plant densities evaluated in strip inter-crop with soybean. The trial was factorial, laid out in a randomized complete block design and replicated three times. Thus, 8 maize-soybean strip cropping systems and application of 3 NPK rates were evaluated at Saki-Oyo, Ilorin, and Nasarawa (southern Guinea savanna), Kaduna in the northern Guinea savanna, Funtua (Katsina) and Gusau (Zamfara) located within Sudan savanna ecologies of Nigeria. Data on yields and yield components were collected. The intercropping systems were assessed using existing intercropping indices such as Land Equivalent Ratio (LER), Relative Crowding Coefficient (K), Aggressivity (A), Competitive Ratio (CR), Actual Yield Loss (AYL), Intercropping Advantage (IA) and Monetary Advantage Index (MAI). The result showed that Nasarawa and Kaduna were most ideal locations for maize production in the Nigeria savannas. The highest grain yield of 4.04 tons/ha maize and 1.36 tons/ha soybean were obtained from seeding 1 plant/stand in 2-rows per ridge x 4 ridges of maize alternated with 2 rows of soybean with the application of NPK at 100:50:50. The LER was 1.11, AYL (1.10) and MAI (208) gave a profit of ₦312,102.00 (US$990.80) ha-1 with a benefit-cost ratio of 2.38 and production efficiency of 29.56%. The study concluded that, seeding 80% maize and 20% soybean per ha will lead to sustainable maize crop production with limited use of fertilizer. It can be adopted by the farmers in Nigeria savannas as a relatively profitable intercropping system.
 Keywords: Maize production, Ideal location, Fertilizer rate, Competitive indices, Savanna ecologies, Nigeria

Nutrient Accumulation and Distribution Assessment in Response to Potassium Application under Maize–Soybean Intercropping System

Intercropping is an intensive agricultural cropping system widely practiced for enhanced yield and nutrient acquisition advantages. A two-year maize–soybean intercropping (MSI) field study was performed in 2018 and 2019 to assess the effects of potassium (K) fertilizer application on biomass accumulation and distribution of essential nutrients in the various plant parts (root, green biomass and seed) of maize–soybean intercropping (MSI). Three different treatments of K fertilizer applications (T0: no potassium application; T1: maize 40, soybeans 30 and T2: maize 80, soybeans 60 kg ha−1) were designed with 2 rows of maize by wide, narrow row planting in row arrangements of 160 cm + 40 cm. Soybeans were grown in 2 wide rows at a width of 40 cm and a row spacing of 60 cm between the rows of maize and soybeans, while the sole maize (SM) and sole soybean (SS) were grown with 70-cm and 50-cm row spacing, respectively. The results of the two-year study confirmed that, as compared to T0, T2 significantly increased nitrogen, phosphate and potassium (NPK) accumulation in all maize parts by 27%, 16% and 20% grain, 23%, 22% and 14% green biomass and 30%, 17% and 15% root, respectively. In soybean treatments, T2 significantly increased NPK accumulation by 23%, 22% and 24% grain, 16%, 15% and 12% green biomass and 18%, 19% and 20% root, respectively. The increased accumulation of nutrients under T2 raised the overall biomass and its distribution to root, green biomass and grain in maize and soybeans by 11% and 18% and 16% and 19%, 20% and 12%, respectively, compared to T0. On average, after two years of experiments, the T2 intercropped maize and the soybeans showed 103% and 64% of the sole yield and attained the maximum LER of 1.66 and 1.68, respectively. Our results reveal that managing optimum K level application (80:60 kg ha−1) can accelerate biomass accumulation and distribution of other essential nutrients in the plant parts of intercropped maize and soybeans. Therefore, it is immensely important to concern potassium application levels in developing a sustainable maize–soybean intercropping systems for achieving higher productivity and land equivalent ratio (LER).

Optimum strip width increases dry matter, nutrient accumulation, and seed yield of intercrops under the relay intercropping system

AbstractStrip width management is a critical factor for producing higher crop yields in relay intercropping systems. A 2‐year field experiment was carried out during 2012 and 2013 to evaluate the effects of different strip width treatments on dry‐matter production, major‐nutrient (nitrogen, phosphorus, and potassium) uptake, and competition parameters of soybean and maize in relay intercropping system. The strip width (SW) treatments were 0.40, 0.40, and 0.40 m (SW1); 0.40, 0.40, and 0.50 m (SW2); 0.40, 0.40, and 0.60 m (SW3); and 0.40, 0.40, and 0.70 m (SW4) for soybean row spacing, maize row spacing, and spacing between soybean and maize rows, respectively. As compared to sole maize (SM) and sole soybean (SS), relay‐intercropped maize and soybean accumulated lower quantities of nitrogen, phosphorus, and potassium in all treatments. However, maize in SW1 accumulated higher nitrogen, phosphorus, and potassium than SW4 (9%, 9%, and 8% for nitrogen, phosphorus, and potassium, respectively). Soybean in SW3 accumulated 25% higher nitrogen, 33% higher phosphorus, and 24% higher potassium than in SW1. The improved nutrient accumulation in SW3 significantly increased the soybean dry matter by 19%, but slightly decreased the maize dry matter by 6% compared to SW1. Similarly, SW3 increased the competition ratio value of soybean (by 151%), but it reduced the competition ratio value of maize (by 171%) compared to SW1. On average, in SW3, relay‐cropped soybean produced 84% of SS seed yield and maize produced 98% of SM seed yield and achieved the land equivalent ratio of 1.8, demonstrating the highest level in the world. Overall, these results suggested that by selecting the appropriate strip width (SW3; 0.40 m for soybean row spacing, 0.40 m maize row spacing, and 0.60 m spacing between soybean and maize rows), we can increase the nutrient uptake (especially nitrogen, phosphorus, and potassium), dry‐matter accumulation, and seed yields of relay‐intercrop species under relay intercropping systems.

Efficiency of the Adapted Automatic Row Hoe for Weed Control in Organic Soybean

The objective of the present study was to evaluate the row hoe model CHOPSTAR®, the mechanical control of weeds in between the rows of soybean implanted in organic direct sowing system, associated with the camera-guided system. Two experiments were carried, being that in the first experiment an experimental design with sub-subdivided plots with four replicates. The plots corresponded to two soybean varieties (‘Embrapa BRS 284’ and ‘Coodetec CD 216’), the subplots corresponded to the sowing densities of 329.2 and 574.6 thousand plants ha-1; and the sub-subplots corresponded to four managements of weeds: one mechanized hoe (2 days after sowing – DAS), two mechanized hoes (22 and 47 DAS), one control manually hoed and other control without hoeing. In the second experiment a randomized block design in subdivided plots with three replicates was used. The plots corresponded to two soybean varieties (‘BRS 284’ and ‘DF 2353’), the subplots constituted of different times when the hoes were made, being: one (14 DAS); two (7 and 21 DAS; two (14 and 28 DAS); three (7, 14 and 28 DAS); besides one control manually hoed up to 28 DAS. In the first experiment it was observed that the automatized hoe was efficient in controlling the weeds and it was necessary only one mechanized hoe (22 DAS) for the ‘BRS 284’ independent of the sowing density, while for the ‘CD 216’ the number of mechanized hoes depended on the sowing density. In the second experiment, it was necessary only one mechanized hoe (14 DAS) to avoid production losses in the varieties ‘BRS 284’ and ‘DF 2353’. The automatized hoe is an alternative to control weeds in areas of organic soybean in direct sowing system, however, damages to the crop can occur depending on the sowing density, mainly in the late management of the mechanized hoe.

Crop Productivity and Nutrients Recovery in Maize–Soybean Additive Relay Intercropping Systems Under Subtropical Regions in Southwest China

Limited arable land area and deteriorating soil health in smallholder farmers’ fields of subtropical regions in China have led to an urgent demand for sustainable production practices with greater land productivity and nutrients use efficiency. A group of field experiments at three locations (Yaan, Lezhi and Renshou) in two consecutive years of 2012–2013 were conducted to study crop production and nutrients recovery of maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) in monocropping and additive relay intercropping systems. The results showed that the total crop yields of the 2:2 maize-to-soybean wide-narrow row spacing planting pattern (RIwn) were significantly higher than that of the 1:1 maize-to-soybean equal row spacing planting pattern (RIe), and the average land equivalent ratios (LER) of the grain yield were 1.79 and 1.49 for the RIwn and RIe, respectively. The nitrogen (N), phosphorus (P) and potassium (K) recovery efficiency calculated by the ratios of crop nutrients removed and fertilizer input indicated that the RIwn had a higher nutrients recovery than the RIe due to proper spacing between maize and soybean rows and higher soybean yield in RIwn. In terms of the amount of fertilizer applied, based on this experiment, P should be reduced in maize plantings and increased in soybean plantings to maintain the balance of soil P. Considering the higher temperatures during the soybean vegetative growth phase, N fertilizer inputs should be controlled to prevent excessive soybean growth. In addition, excess K was taken up in the crop biomass, maybe the straw should be returned to the field to maintain soil K fertility sustainable for the long term.

Production, fermentation profile, and nutritional quality of silage from corn and soybean intercropping

Forage seasonality makes farmers use conservation practices. Mixing corn silage and legumes can enhance silage quality and hence animal productivity. Therefore, this study aimed to evaluate yield and quality of silages from intercropping between genetically modified corn and soybean for glyphosate tolerance (RR - Roundup Ready) as a function of plant spatial arrangement, soybean variety, and sowing fertilization methods. Two intercropping arrangements of RR corn and RR soybeans were tested: alternate single rows of corn and soybeans and double corn rows for each soybean row. Treatments were randomized blocks with four replications, arranged in a 2x2+1 factorial scheme. The first factor was sowing fertilization method (2): only in corn rows or in total area. The second factor was soybean variety (2): medium- and late-cycle genotypes, and an additional treatment of corn monoculture. After harvest, forage material was analyzed for agronomic characteristics and then ensiled for 60 days. Thereafter, bromatological composition, fermentation profile, and losses were analyzed during silage fermentation process. No differences were observed among treatments for total silage production. Overall, silage from intercropping treatments showed higher levels of hemicellulose, total digestible nutrients, crude protein, and ether extract, thus improving silage quality. However, lower contents of dry matter, acid detergent fiber, and cellulose were also observed in silage from intercropped treatments. In short, adding soybeans to silage can improve final roughage, reducing costs of protein and energy supplements.

Integrated pigweed (Amaranthus spp.) management in glufosinate-resistant soybean with a cover crop, narrow row widths, row-crop cultivation, and herbicide program

AbstractSuccessful pigweed management requires an integrated strategy to delay the development of resistance to any single control tactic. Field trials were implemented during 2017 and 2018 in three counties in Kansas on dryland (limited rainfall, nonirrigated), glufosinate-resistant soybean. The objective was to assess pigweed control with combinations of a winter wheat cover crop (CC), three soybean row widths (76, 38, and 19 cm), row-crop cultivation 2.5 weeks after planting (WAP), and an herbicide program to develop integrated pigweed management recommendations. All combinations of the four components were assessed by 16 treatments. All treatments with the herbicide program resulted in excellent (>97%) pigweed control and were analyzed separately from the other components. Treatments containing row-crop cultivation reduced pigweed density and biomass 3 and 8 WAP in all locations compared with the 76-cm row width plus no CC treatment. CC impacts were mixed. In Riley County, Palmer amaranth density and biomass were reduced; in Reno County, no additional Palmer amaranth control was observed; in Franklin County, the CC had greater waterhemp density and biomass compared with the treatments containing no CC. Narrow row widths achieved the most consistent results of all cultural components when data were pooled across locations: Decreasing row widths from 76 to 38 cm resulted in a 23% reduction in pigweed biomass 8 WAP and decreasing row width from 38 to 19 cm achieved a 15% reduction. Row-crop cultivation should be incorporated where possible as a mechanical option to manage pigweed, and narrow row widths should be used to suppress late-season pigweed growth when feasible. Inconsistent pigweed control from CC was achieved and should be given special consideration before implementation. The integral use of these components with an herbicide program as a system should be recommended to achieve the best pigweed control and reduce the risk of developing herbicide resistance.

Narrow-wide row planting pattern improves the light environment and seed yields of intercrop species in relay intercropping system.

Different planting patterns affect the light interception of intercrops under intercropping conditions. Here we revealed that narrow-wide-row relay-intercropping improves the light interception across maize leaves in wide rows (60cm) and narrow rows (40cm), accelerated the biomass production of intercrop-species and compensated the slight maize yield loss by considerably increasing the soybean yield. In a two-year experiment, maize was planted with soybean in different planting patterns (1M1S, 50:50cm and 2M2S, 40:60cm) of relay-intercropping, both planting patterns were compared with sole cropping of maize (M) and soybean (S). As compared to M and 1M1S, 2M2S increased the total light interception of maize leaves in wide rows (WR) by 27% and 23%, 20% and 10%, 16% and 9% which in turn significantly enhanced the photosynthetic rate of WR maize leaves by 7% and 5%, 12% and 9%, and 19% and 4%, at tasseling, grain-filling and maturity stage of maize, respectively. Similarly, the light transmittance at soybean canopy increased by 218%, 160% and 172% at V2, V5 and R1 stage in 2M2S compared with 1M1S. The improved light environment at soybean canopy in 2M2S considerably enhanced the mean biomass accumulation, and allocation to stem and leaves of soybean by 168%, and 131% and 207%, respectively, while it decreased the mean biomass accumulation, and distribution to stem, leaves and seed of maize by 4%, and 4%, 6% and 5%, respectively than 1M1S. Compared to 1M1S, 2M2S also increased the CR values of soybean (by 157%) but decreased the CR values of maize (by 61%). Overall, under 2M2S, relay-cropped maize and soybean produced 94% and 69% of the sole cropping yield, and the 2M2S achieved LER of 1.7 with net income of 1387.7 US $ ha-1 in 2016 and 1434.4 US $ ha-1 in 2017. Our findings implied that selection of optimum planting pattern (2M2S) may increase the light interception and influence the light distribution between maize and soybean rows under relay-intercropping conditions which will significantly increase the intercrops productivity. Therefore, more attention should be paid to the light environment when considering the sustainability of maize-soybean relay-intercropping via appropriate planting pattern selection.

Row Arrangements of Maize and Soybean Intercrop on Silage Quality and Grain Yield

The success of maize + soybean intercrop depends on the plant arrangement. An experiment was carried out to evaluate different row arrangements on intercrop forage yield, silage quality and maize grain yield in relation to maize as a sole crop. The experiment was set up with a randomized complete block design with eight row arrangements between maize and Soybean. Maize biomass yield among crop arrangements were similar, although, lower than the maize sole crop. On the other hand, these treatments showed higher soybean biomass yield, which in turn increased silage crude protein and crude protein yield per unit area. Maize thousand grain weight, grain yield per plant and per area was affected by the intercrop arrangements. The use of two corn rows + two soybean rows (2M+2S-30 cm) and four corn rows + four soybean rows (4M+4S-30 cm) showed higher crude protein yield per area associated with similar maize grain yield in relation to the sole maize crop. In conclusion, alternating four maize rows with four soybean rows was the optimum row ratio in maize + soybean intercrop, though this needs to be further confirmed by more trials.

Združivanje useva prosa i soje za proizvodnju biomase

Sustainable agriculture considers production of high quality food and feed with minimal impact on environment. Intercropping is one of the most efficient ways to produce valuable biomass for animal feed rich in nutrients. Intercrop combinations: alternating rows of soybean and proso millet (S-M), alternating strips with 2 rows of soybean and 2 rows of millet (SS-MM-SS) and alternating strips with 2 rows of soybean and 4 rows of millet (SS-MMMM-SS); single crop of soybean and single crop of proso millet were tested. The effect of bio-fertilizer Coveron was also followed. Aboveground biomass was harvested and land equivalent ratio (LER), as well as leaf area index (LAI) was determined. All intercropping combinations increased LAI of soybean when compared to monocrop, to 43% and 84% in SS-MM-SS combination with and without Coveron, respectively. Coveron slightly increased LAI. The highest values of biomass yield were obtained in S-M intercrop for soybean (39% and 42% higher in relation to monocrop, in combination with and without Coveron, respectively) and in monocrop for proso millet. Nevertheless, the highest LER value was obtained for SS-MM-SS combination without Coveron (1.12). In intercrops treated with Coveron slightly lower LER values were obtained for S-M and SS-MMMM-SS combination (0.97 and 0.98, respectively). Irrespective to sowing way, results indicate that 1:1 ratio of soybean and proso millet in intercrop (S-M and SS-MM-SS combinations) is the most promising way to achieve high biomass yield.

Effects of Palmer Amaranth (Amaranthus palmeri) Establishment Time and Distance from the Crop Row on Biological and Phenological Characteristics of the Weed: Implications on Soybean Yield

AbstractInformation about weed biology and weed population dynamics is critical for the development of efficient weed management programs. A field experiment was conducted in Fayetteville, AR, during 2014 and 2015 to examine the effects of Palmer amaranth (Amaranthus palmeriS. Watson) establishment time in relation to soybean [Glycine max(L.) Merr.] emergence and the effects ofA. palmeridistance from the soybean row on the weed’s height, biomass, seed production, and flowering time and on soybean yield. The establishment time factor, in weeks after crop emergence (WAE), was composed of six treatment levels (0, 1, 2, 4, 6, and 8 WAE), whereas the distance from the crop consisted of three treatment levels (0, 24, and 48 cm). Differences inA. palmeribiomass and seed production averaged across distance from the crop were found at 0 and 1 WAE in both years. Establishment time had a significant effect onA. palmeriseed production through greater biomass production and height increases at earlier dates.Amaranthus palmerithat was established with the crop (0 WAE) overtopped soybean at about 7 and 10 WAE in 2014 and 2015, respectively. Distance from the crop affectedA. palmeriheight, biomass, and seed production. The greater the distance from the crop, the higherA. palmeriheight, biomass, and seed production at 0 and 1 WAE compared with other dates (i.e., 2, 4, 6, and 8 WAE).Amaranthus palmeriestablishment time had a significant impact on soybean yield, but distance from the crop did not. The earlierA. palmeriinterfered with soybean (0 and 1 WAE), the greater the crop yield reduction; after that period no significant yield reductions were recorded compared with the rest of the weed establishment times. Knowledge ofA. palmeriresponse, especially at early stages of its life cycle, is important for designing efficient weed management strategies and cropping systems that can enhance crop competitiveness. Control ofA. palmeriwithin the first week after crop emergence or reduced distance between crop and weed are important factors for an effective implementation of weed management measures againstA. palmeriand reduced soybean yield losses due to weed interference.

Estimation of nitrogen and carbon content from soybean leaf reflectance spectra using wavelet analysis under shade stress

Changes in leaf carbon and nitrogen traits are effective parameters for evaluating whether plants are growing normally and for guiding field management measures. Therefore, a nondestructive estimation of soybean leaf carbon content (LCC) and leaf nitrogen content (LNC) is important for managing soybean production. This study aims to investigate the properties of soybean LCC, LNC and leaf carbon and nitrogen ratio (LCNR) under different light conditions and to construct the estimation models for soybean LCC, LNC and LCNR on the basis of hyperspectral reflectance. A 3-year field trial was conducted from 2013 to 2015 to investigate the effect of five shade treatments (from 57% to 18% of normal photosynthetic active radiation) by regulating the distance between maize and soybean rows in an intercropping system.Results showed that the LNC is increased, and the LCC is decreased with the increase in shading level. A typical leaf hyperspectral reflectance showed that the changes in near infrared and around the green peak are approximately proportional to the LCC and analogously inverse to the LNC. The corresponding first-order derivative presented the changes in the red-edge positions as a ‘blue shift’ with the increase in shading level. General vegetation indices (VIs), uninformative variable elimination-partial least squares (UVE-PLS) and continuous wavelet transform (CWT) were used to develop the models. The linear models constructed using the CWT, compared with the VIs and UVE-PLS, had the highest determination coefficient and the lowest root mean square error (RMSE). The models were validated using independent data from 2015 with RMSE values of 1.9789, 0.6132 and 2.1587 for the LCC, LNC and LCNR, respectively. Moreover, these models obtained relative errors of 4.5%, 13.2% and 20% for the LCC, LNC and LCNR, respectively. Results indicated that soybean LNC and LCC can be accurately estimated using the CWT for assessing the physiological situation.

Effects on Soybean Growth and Yield of Wheat-Soybean Intercropping System

It has been demonstrated that soybean (Glycine max) produces lower yields at relay intercropping with wheat (Triticum aestivum) than if it is sown as a sole crop. However, most studies considered wider or irregular soybean row spacing, compromising its capacity to recover after wheat harvest. This work studied the stress effects in relay soybean intercropping and suggests narrowing row spacing to improve soybean performance. The aims were (i) to compare growth and yield of two planting patterns and (ii) to separate the effect of water stress (WS) from the effects of other stress factors (OSF) induced by wheat on intercropping soybean. WS was evaluated comparing above-ground dry and grain yield of irrigated and non irrigated intercropping soybean, and OSF was evaluated comparing intercropping soybean with another treatment in which wheat straw (aerial biomass) was eliminated at soybean emergence, both irrigated treatments. In wheat, similar yields were obtained in treatments with an intercropping planting pattern with two rows for wheat and one for soybean (2:1) compared to three rows for wheat and one row for soybean (3:1). However, intercropping soybean at narrow row spacing (52 cm; 2:1) improve yielded 23% more than intercropping at 70 cm (3:1). During wheat-soybean coexistence, OSF prevailed on soybean and this effect persisted in later stages. After wheat harvest, OSF reduced the amount of light interception from R1 to R5 and depressed the crop growth rate (CGR) in 34%. However, in this period, WS also affected the radiation use efficiencies (RUE) which explained the greater fraction (66%) of the total stress induced by wheat in soybean CGR. Intercrop soybean yielded 182 g m-2 less compared to the unstressed sole crop control. Considering the wheat effects on soybean growth, 63% (116.5 g m-2) of the total yield lost were due to WS. Therefore, most of the performance of relay intercropping soybean was linked with water disponibility since early stages. However, at optimum water condition wheat competition by light and resources also affected soybean yield (OSF: 37%).

Keanekaragaman serangga pengunjung bunga pada tanaman tumpang sari kedelai dengan tanaman orok-orok (Crotalaria juncea)

Tumbuhan berbunga dapat meningkatkan populasi serangga polinator, yang sekaligus berperan penting dalam meningkatkan hasil tanaman. Tujuan penelitian ini untuk mengetahui pengaruh tumpang sari Crotalaria juncea dengan kedelai terhadap keanekaragaman serangga pengunjung bunga dan polinator alami terhadap hasil kedelai. Penelitian dirancang pada petak tunggal, dengan perlakuan: tanpa C. juncea (kontrol), penanaman C. juncea mengelilingi lahan kedelai, penanaman C. juncea setiap 5 baris kedelai, dan penanaman C. juncea setiap 10 baris kedelai. Pengaruh polinator alami terhadap hasil kedelai diamati melalui penyungkupan tanaman dengan jaring serangga. Hasil penelitian menunjukan, bahwa penanaman C. juncea dapat meningkatkan keanekaragaman serangga pengunjung bunga. Indeks keanekaragaman tertinggi 2,37 tercatat pada petak penanaman C. juncea setiap 10 baris kedelai. Keanekaragaman serangga pengunjung bunga terbanyak, yaitu 18 spesies ditemukan pada perlakuan penanaman C. juncea setiap 5 baris kedelai. Serangga pengunjung bunga yang dominan adalah Coccinella transversalis, Apis mellifera, Xylocopa virginica, Megachile parientina, Megachile relativa, Ropalidia fasciata, dan Vespa sp. Polinator alami (tanpa sungkup) dapat meningkatkan jumlah polong 30,11%, jumlah biji 44,63%, dan berat biji per tanaman 15,44% sehingga berperanan penting pada hasil kedelai.

Crop productivity and chemical compositions of black cumin essential oil in sole crop and intercropped with soybean under contrasting fertilization

Intercropping systems and the application of organic manures play an important role in increasing of quantity and quality of plant products. In order to evaluate the quantity and quality of black cumin products under contrasting fertilization, a factorial experiment was conducted in a randomized complete block design with three replications in 2016. Soybean and black cumin seeds were sown in five planting patterns (sole black cumin, sole soybean and three intercropping ratios of soybean: black cumin (1:2): one row of soybean plus two rows of black cumin, soybean: black cumin (1:1): one row of soybean plus one row of black cumin and soybean: black cumin (2:1): two rows of soybean plus one row of black cumin. All these cropping systems were received organic manure and chemical fertilizer. The results indicated that the highest seed yield (on an average by 86 g m−2) of black cumin was achieved in sole crop of black cumin treated with organic manure. The maximum seed yield of soybean (on an average by 247 g m−2) and land equivalent ratio (1.06) was obtained in two rows of soybean + one row of black cumin under the application of chemical fertilizer. The p-cymene (20.51–62.77%), carvacrol (2.40–25.99%), longifolene (1.11–24.69%) and spathulenol (0.9–14.45%) were major chemical compositions of black cumin. The highest content of p-cymene and carvacrol of black cumin essential oil were recorded in one row of soybean + two rows of black cumin with the application of chemical fertilizer and one row of soybean + one row of black cumin under chemical fertilizer, respectively. The highest longifolene and spathulenol content was observed in one row of soybean + two rows of black cumin treated with organic manure. These major chemical compositions are useful for industrial use (food and pharmaceutical). Therefore, according to different subjects of applying in industries it could be suggested especial treatment with favorite major compounds.

Candidate Tools for Integrated Weed Management in Soybean at the Northern Frontier of Production

AbstractThe development of early-maturing soybean [Glycine max(L.) Merr.] varieties has led to an increase in soybean production in canola (Brassica napusL.)-dominant crop rotations in western Canada. Herbicide-resistant (HR) volunteerB. napuscan be difficult to manage in HR soybean using herbicides alone. In 2013 and 2014, four field experiments were conducted in Manitoba, Canada, to evaluate soybean row spacing, seeding density, nitrogen supply, and interrow tillage as candidate nonchemical weed management tools for an integrated program to manage volunteerB. napusin soybean. Among treatments and sites, volunteerB. napusproduced about 830 seeds plant−1and resulted in large seedbank inputs (averaging about 20,300 seeds m−2). VolunteerB. napusseedling recruitment differed among sites, and resulted in two distinct classes of sites based on average seedling densities of 39 and 89 plants m−2. Weed management tools were more effective at the sites with higher volunteerB. napusdensities. At these sites, soybean yield was greater when using an increased soybean-seeding density (44% greater yield using a seeding density of 682,500 vs. 455,000 seeds ha−1) or interrow tillage (36% greater yield with vs. without using interrow tillage). Soybean row spacing (19 vs. 38 vs. 76 cm) did not affect soybean yield, unless the reduction in row spacing was combined with an increased seeding density (65% greater yield with narrow-row soybean seeded at 682,500 vs. wide-row soybean seeded at 455,000 seeds ha−1). At the sites with higher volunteerB. napusdensities, seed production of canola volunteerB. napuswas greater when nitrogen fertilizer was applied to simulate an environment with greater nitrogen supply (77% greater number of volunteerB. napusseeds produced with vs. without broadcast application of 23 kg N ha−1urea). In northern climates, seeding soybean at increased densities using narrow-row spacing in fields with limited soil inorganic nitrogen and using interrow tillage in wide-row production systems are effective strategies that could augment chemical weed management in an integrated program for management of volunteerB. napus, and perhaps also other competitive early-season weeds.

The effect of organic manure and chemical fertilizer on essential oil, chemical compositions and antioxidant activity of dill (Anethum graveolens) in sole and intercropped with soybean (Glycine max)

Intercropping and the application of organic manure are important approaches for increasing of quantity and quality of plant products. In this experiment, chemical compositions and antioxidant activity of dill essential oil in sole crop and dill-soybean intercropping system under organic manure and chemical fertilizers were evaluated. The results showed that optimal yield of dill and the highest land equivalent ratio (LER) and antioxidant activity (2.43 μg ml−1) of dill were achieved in pattern of two rows of soybean + one row of dill treated with organic manure. Carvone (22.06–49.66%), α-phellandrene (10.79–34.49%), p-cymene (21.66–33.69%) and dillapiole (1.35–12.14%) were major chemical components of dill. The dill-soybean intercropping and application of organic manure enhanced the content of α-phellandrene and p-cymene as well. These major chemical compositions are useful for industrial use (food and pharmaceutical). So, according to different subjects of applying in industries it could be suggested especial treatment with favorite major compounds. In general, soybean-dill intercropping and the application of organic manure enhanced the productivity of dill and improved essential oil quality and antioxidant activity.

Spatiotemporal Distribution Pattern of Sclerotinia sclerotiorum Apothecia is Modulated by Canopy Closure and Soil Temperature in an Irrigated Soybean Field.

Identifying the optimal timing for fungicide application is crucial in order to maximize the control of Sclerotinia stem rot (SSR), which is caused by Sclerotinia sclerotiorum. In this study, the impact of canopy closure and soil temperature on apothecia production was investigated to optimize fungicide application timing. Replicated soybean plots with a row spacing of 0.36 and 0.38 or 0.76 m were established in 2015 and 2016 in an irrigated soybean field at Michigan State University's Montcalm Research Center. The number of apothecia and ascospores and the incidence of SSR were monitored two times per week for 10 to 12 weeks. In both row-spacing trials, apothecia were observed earlier in 2016 (before the R1 growth stage) than in 2015 (between R1 and R2). The maximum number of apothecia was 50 times higher with the 0.36-m row spacing than with the 0.76-m row spacing in 2015 but was 2.5 times higher with the 0.76-m row spacing than with the 0.38-m row spacing in 2016, though the overall numbers were much lower in 2016. The apothecia distribution pattern was synchronized with the canopy closure pattern and the soil temperature profile. The peak number of apothecia was observed when canopy closure reached at least 50% and when average soil temperature in the row was between 21.5 and 23.5°C. In 91% of the cases, the presence of apothecia was observed when the percentage of light blocked was 70%, and no apothecia germinated in the absence of light or under full light exposure. During the first 50 days after plant emergence, the rate of canopy closure was higher in 2016 than in 2015, and the first diseased plant was observed earlier in 2016 (R2) than in 2015 (R5). Canopy closure and the distance of the sampling point from the soybean row explained much of the variability in the number of apothecia. These results can partially explain the inconsistent efficacy of fungicide applications based on the soybean growth stage and will be helpful for informing disease models and fine-tuning fungicide application strategies.

Effect of shading and light recovery on the growth, leaf structure, and photosynthetic performance of soybean in a maize-soybean relay-strip intercropping system.

Intercropping is an important agronomic practice adopted to increase crop production and resource efficiency in areas with intensive agricultural production. Two sequential field trials were conducted in 2015–2016 to investigate the effect of shading on the morphological features, leaf structure, and photosynthetic characteristics of soybean in a maize-soybean relay-strip intercropping system. Three treatments were designed on the basis of different row configurations A1 (“50 cm + 50 cm” one row of maize and one row of soybean with a 50 cm spacing between the rows), A2 (“160 cm + 40 cm” two rows of maize by wide-narrow row planting, where two rows of soybean were planted in the wide rows with a width of 40 cm, and with 60 cm row spacing was used between the maize and soybean rows), and CK (sole cropping of soybean, with 70 cm rows spacing). Results showed that the photosynthetically active radiation transmittances of soybean canopy at V5 stage under A2 treatment (31.1%) were considerably higher than those under A1 (8.7%) treatment, and the red-to-far-red ratio was reduced significantly under A1 (0.7) and A2 (1.0) treatments compared with those under CK (1.2). By contrast with CK, stem diameter, total aboveground biomass, chlorophyll content and net photosynthetic rate decreased significantly except plant height under A1 and A2. The thickness of palisade tissue and spongy tissue of soybean leaf under A1 and A2 were significantly reduced at V5 stage compared with CK. The leaf thicknesses under A1 and A2 were lower than those in CK by 39.5% and 18.2%, respectively. At the R1 stage of soybean (after maize harvest), the soybean plant height, stem biomass, leaf biomass and petiole biomass under A1 and A2 treatments were still significantly lower than those under CK, but no significant differences were observed in Chl a/b, Pn, epidermis thickness and spongy tissue thickness of soybean leaves in A2 compared with CK. In addition, the soybean yields (g plant-1) under A1 and A2 were 54.69% and 16.83% lower than those in CK, respectively. These findings suggested that soybean plants can regulate its morphological characteristics and leaf anatomical structures under different light environments.

Effect of Formulations and Spray Nozzles on 2,4-D Spray Drift under Field Conditions

Six trials were conducted during 2014/15 and 2015/16 growing seasons in Brazil to determine the effect of 2,4-D formulations and spray nozzles on 2,4-D spray drift under conventional field conditions. An experimental 2,4-D choline formulation with Colex-D® Technology (GF-3073) and a 2,4-D dimethylamine (DMA) formulation were applied with either XR and AIXR flat-fan spray nozzles. Each plot was 30 m wide by 24 m long (720 m2) with 60 glyphosate-resistant soybean rows spaced 50 cm apart and also 35 potted tomato plants distributed on a grid across the plot 5-m apart. Applications were performed one meter away from the plot edge perpendicular to the soybean rows when wind direction was parallel to the rows with less than 30 degrees of angle deviation. Spray drift treatments were applied in 100 L ha−1 with tractor sprayers at 276 kPa equipped with a 7-m wide boom at 50 cm above the canopy of the soybean plant, operating at 6.8 km h−1. The distance from the plot edge to the farthest plant with 2,4-D symptoms was assessed for every four soybean rows at 10 and 20 days after treatment (DAT) and potted tomatoes at 10 DAT. GF-3073 reduced the distance of the farthest injured plant with 2,4-D symptoms compared to the 2,4-D DMA formulation regardless of the spray nozzle, assessment date and sensitive species. GF-3073 applied through the AIXR nozzle reduced the relative drift affected area to the standard by 68% at 10 DAT and 67% at 20 DAT for soybean and 60% at 10 DAT for potted tomatoes.