Conventional Row Research Articles

Camera-guided Weed Hoeing in Winter Cereals with Narrow Row Distance

Farmers are facing severe problems with weed competition in cereal crops. Grass-weeds and perennial weed species became more abundant in Europe mainly due to high percentages of cereal crops in cropping systems and reduced tillage practices combined with continuous applications of herbicides with the same mode of action. Several weed populations have evolved resistance to herbicides. Precision weed hoeing may help to overcome these problems. So far, weed hoeing in cereals was restricted to cropping practices with row distances of more than 200 mm. Hoeing in cereals with conventional row distances of 125–170 mm requires the development of automatic steering systems. The objective of this project was to develop a new automatic guidance system for inter-row hoeing using camera-based row detection and automatic side-shift control. Six field studies were conducted in winter wheat to investigate accuracy, weed control efficacy and crop yields of this new hoeing technology.A three-meter prototype and a 6-meter segmented hoe were built and tested at three different speeds in 150 mm seeded winter wheat. The maximum lateral offset from the row center was 22.53 mm for the 3 m wide hoe and 18.42 mm for the 6 m wide hoe. Camera-guided hoeing resulted in 72–96% inter-row and 21–91% intra-row weed control efficacy (WCE). Weed control was 7–15% higher at 8 km h−1 compared to 4 km h−1. WCE could be increased by 14–22% when hoeing was combined with weed harrowing. Grain yields after camera-guided hoeing at 8 km h−1 were 15–76% higher than the untreated control plots and amounted the same level as the weed-free herbicide plots. The study characterizes camera-guided hoeing in cereals as a robust and effective method of weed control.

Differences in grain yield responses to planting density in twin and narrow row cultivation between early and late maize cultivars

AbstractWe investigated how two planting patterns, twin row (TR) and narrow row (NR), affected maize grain yield compared with conventional row (CR) cultivation at five different planting densities, ranging from 7 to 12 plants/m2, over 2 years using early and late cultivars. For all the planting patterns, the relationship between grain yield and planting density could be fit using the quadratic curve Y = a (X − b)2 + c at the <1% level of significance, where a represents grain yield response to planting density, and c represents the maximum yield. Regardless of the cultivar’s maturation period, the magnitude of a was smaller for TR than for NR and CR. Although the late cultivar had a higher c value than the early cultivar, the a value and annual difference were larger. For the early and late cultivars, TR at 10.8 and 9.9 plants/m2, respectively, easily achieved stable high grain yields. The large magnitude of the grain yield response to planting density for the late cultivar was caused by the large decrease in the number of grains per ear and the harvest index at an above optimum planting density. This large decrease and instability in yield‐related traits resulted from a high maximum leaf area index, the frequent mutual shading of leaf blades and the large differences between the years.

Formation of botanical composition of clover cereal and alfalfa cereal crops agrophytocenoses depending on sowing method

Botanical composition of grasses is one of the most important indicators the biological value and quality of the obtained hay and pasture forage, the longevity of hayfi elds and pastures depend on. The issue of changing the botanical composition of agrophytocenoses is especially important in the context of global climate change, which in recent decades is also manifested in the territory of Ukraine, as it is possible to establish the most adapted species of legumes and cereals to adverse weather conditions and to identify eff ective technological methods of managing these processes for maximum conservation economically valuable species in the herbage. The purpose of the research is to establish the infl uence of diff erent ways of sowing of clover and alfalfa cereal crops agrophytocenoses on the formation of their botanical composition. Field studies have established diff erent eff ects of conventional in-line, cross-section and cross-sectional methods of sowing on the formation of botanical composition of grass mixtures of clover meadow (Trifolium pratense) varieties Sparta and Pavlyna with timothy meadow (Phleum pratense) and fenugreek multifl oral (Lolium multifl orum) and of agrophytocenoses of alfalfa of Sinyukha and Seraphima sowing varieties with reed fire (Festuca arundinacea Schreb) and middle wheatgrass (Elytrigia intermedia). For the average of four years of life of clover and alfalfa cereal crops agrophytocenoses, the highest proportion of legume component was observed with split-cross sowing – 51.6 % for Sparta, 53.1 % for Pavlyna, 60.3 % for Seraphima and 61.6 % for the Sinyukha variety. In the fourth year of life (the third year of use) of sowed leguminous-cereals agrophytocenoses, the preservation of the legume component was 14.6–15.5 % in clover-cereals grass mixtures with the Sparta variety and 16.0–16.8 % with the Pavlyna variety. In alfalfa grasslands, these indicators were 54.0–55.1 % with Seraphim and 55.0–56.2 % with Sinyukha. Among the studied varieties of clover meadow and alfalfa sowing proved better in the conditions of the Forest Steppe of western Pavlyna and Sinyukha. Cross-sectional and divided cross-sectional sowing of legumes and cereals mixtures proved to be better compared to conventional row crops in terms of conservation of economically valuable grass species. Key words: agrophytocenosis, botanical composition, clover meadow, alfalfa sowing, sowing methods.

Birds suppress pests in corn but release them in soybean crops within a mixed prairie/agriculture system.

Birds provide ecosystem services (pest control) in many agroecosystems and have neutral or negative ecological effects (disservices) in others. Large-scale, conventional row crop agriculture is extremely widespread globally, yet few studies of bird effects take place in these agroecosystems. We studied indirect effects of insectivorous birds on corn and soybean crops in fields adjacent to a prairie in Illinois (USA). We hypothesized that prairie birds would forage for arthropods in adjacent crop fields and that the magnitude of services or disservices would decrease with distance from the prairie. We used bird-excluding cages over crops to examine the net effect of birds on corn and soybean grain yield. We also conducted DNA metabarcoding to identify arthropod prey in fecal samples from captured birds. Our exclosure experiments revealed that birds provided net services in corn and net disservices in soybeans. Distance from prairie was not a significant predictor of exclosure treatment effect in either crop. Many bird fecal samples contained DNA from both beneficial arthropods and known economically significant pests of corn, but few economically significant pests of soybeans. Song Sparrows (Melospiza melodia), one of our most captured species, most commonly consumed corn rootworms, an economically significant pest of corn crops. We estimated that birds in this system provided a service worth approximately US $275 ha-1 in corn yield gain, and a disservice valued at approximately $348 ha-1 in soybean yield loss. Our study is the first to demonstrate that birds can provide substantial and economically valuable services in field corn, and disservices in soybean crops. The contrasting findings in the 2 crop systems suggest a range of bird impacts within widespread agroecosystems and demonstrate the importance of quantifying net trophic effects.

Bacterial community composition in agricultural soils under long‐term organic and conventional management

AbstractOrganic row cropping systems utilize diverse management regimes, but share required practices, including biological fertility sources, diverse rotations, incorporation of organic matter, and lack of synthetic pesticides. The practices can alter the composition of functionally significant soil microbes relative to conventional practices. We used 16S rRNA sequencing to profile soil bacterial communities at five locations where long‐term organic and conventional row cropping were practiced in close proximity on the same underlying soil type. Location effects, reflecting soil characteristics, were stronger than effects of organic vs. conventional management or corn (Zea mays L.) vs. soybean [Glycine max (L.) Merr.] cropping on the relative abundance of bacterial taxa. A core subset of 1,300 operational taxonomic units (OTUs) were detected in all sampled soils. Firmicutes made up a smaller portion of core OTUs than total OTUs, indicating that taxa in this group were more likely to be found only in specific environments. Conversely, Actinobacteria OTUs were more highly represented in the core than the full OTU set, indicating wide distribution of these taxa across environments. The genus Streptomyces comprised a five‐fold–greater proportion of core OTUs than of total OTUs. We identified 303 OTUs whose abundance differed with management system. Of those, members of the phyla Bacteroidetes and Planctomycetes tended to be more abundant under organic management, whereas members of the Actinobacteria and Verrucomicrobia tended to be more abundant in conventional. This multi‐site study contributes to identification of bacterial community members most affected by organic practice adoption across soil types and practices.

Cotton Response to Planting Patterns under Effect of Typical and Limited Irrigation Regime

Decrease of width between cotton (Gossypium hirsutum L.) row spacing has been suggested as an agronomic practice that may increase the yield and reduce the cost production. Altering agronomic practices as row spacing system as well as irrigation regime can affect cotton growth parameters, yield components, and physical fiber properties. The object of this study is the assessment of interaction between row spacing cropping systems and irrigation regime and their effects on yield components. Yield, biomass, harvest index, seed index, seed weight, bolls number, individual boll weight, the proportion of lint and seed were studied in three row spacing systems [conventional row (CR), narrow row (NR) and ultra-narrow row (UNR)] under typical and limited irrigation regime, during two growing seasons. The decrease of row spacing had different effect on yield components under the typical and limited irrigation regime e.g. the differences between systems of row spacing on bolls number were more evident under the limited irrigation than the typical one, and the opposite was true for the lint proportion. Decreased row spacing had positive effects on yield, biomass, bolls number per land area and lint proportion in two irrigation systems. However, had negative impact on individual boll weight, seed weight, seed index, harvest index and seed proportion. Interaction of row spacing and irrigation regime was significant for seed index. High differences were more significant between UNR and CR and less between NR and CR. UNR system appeared to be viable alternative to traditional row system for cotton production.
 
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 In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.
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Grain yield responses to planting density in twin and narrow row cultivation of early cultivars in maize

AbstractWe investigated how the responses of grain yield of maize to planting density depended on planting pattern (twin row, TR; narrow row, NR; narrow twin row, NTR; compared with conventional row (CR) cultivation) over 2 years using cultivars with relative maturity of 93 days. Grain yields were higher in order of NTR ≥ TR ≥ NR ≥ CR in all planting densities. Changes in grain yield and total dry matter yield with planting density followed significant negative quadratic regression curves in all planting patterns, increased with dense planting from 9.7 to 10.4 planting density and decreased thereafter. Changes in number of grains per ear and hundred grain weight with planting density followed significant negative linear regression in all planting pattern, and number of grain per ear, hundred grain weight and harvest index decreased with dense planting. The quadratic coefficient of the quadratic regression model, which indicates the changeability of the planting density response of grain yield, was lowest for NTR, followed by TR, NR and CR. The decline in number of grains per ear in response to increasing planting density for different planting patterns was NTR ≤ TR ≤ NR ≤ CR. The planting density response of total dry matter yield closely follows that of the grain yield in all planting pattern. But decrease in harvest index due to increased planting density for different planting patterns was lowest for NTR, followed by TR, NR and CR. Considering the relationship of grain yield to their related traits, the improved stability of grain yield for the specific planting patterns from the fact that the decline in number of grains per ear for different planting patterns is NTR < TR ≤ NR < CR. The specific planting patterns moderate the decline in harvest index and number of grains per ear with increasing planting density by enabling the maintenance of greater inter‐individual distance a given planting density.

Flood Risk Reduction from Agricultural Best Management Practices

AbstractBest management practices (BMPs) play an important role in improving impaired water quality from conventional row crop agriculture. In addition to reducing nutrient and sediment loads, BMPs such as fertilizer management, reduced tillage, and cover crops could alter the hydrology of agricultural systems and reduce surface water runoff. While attention is devoted to the water quality benefits of BMPs, the potential co‐benefits of flood loss reduction are often overlooked. This study quantifies the effects of selected commonly applied BMPs on expected flood loss to agricultural and urban areas in four Iowa watersheds. The analysis combines a watershed hydrologic model, hydraulic model outputs, and a loss estimation model to determine relationships between hydrologic changes from BMP implementations and annual economic flood loss. The results indicate a modest reduction in peak discharge and economic loss, although loss reduction is substantial when urban centers or other high‐value assets are located downstream in the watershed. Among the BMPs, wetlands, and cover crops reduce losses the most. The research demonstrates that watershed‐scale implementation of agricultural BMPs could provide benefits of flood loss reduction in addition to water quality improvements.

Novel approach to semi-automated warehouse for manufacturing: design and simulation

The purpose of this paper is to present a novel design of semi-automated warehousing system for manufacturing applications. The approach bases on a new type of storage of carriers, called drawer racks. This concept adopts a modified shelving system based on single or double sections of row racks rotated by 90 degrees. Each drawer rack can move perpendicularly to the transportation corridor. The motion of the rack is possible thanks to the automatically guided vehicle that translates under the line of racks. In the paper, we show a comparison between the designed new system and conventional storage solutions for manufacturing. This indicates that the drawer racks require less space per pallet place without a significant interference with a building infrastructure. In this work, we discuss various design solutions for key components of the drawer-rack and AGV that can operate a rack of 40 pallet places. The designed system was tested if it meets the assumed performance level. The simulation model was created in discrete event system environment. We compared the warehouse layout and material flow for conventional row racks with the newly proposed system. We found out that the new system operates at the higher efficiency but requires less space.

Poultry Litter and Cover Crop Integration into No‐till Cotton on Upland Soil

Core Ideas Applying poultry litter to the top of cover crop residue increased lint yield in drier years.This practice enhanced cotton lint yield, soil C, and soil health.This practice reduced NO3–N and water‐soluble P by 49 and 22% in 5‐cm soil depth, a zone of plant–soil–water interactions. The influence of poultry litter (PL) and cover crops have under no‐till cropping systems in Mississippi upland soils on cotton (Gossypium hirsutum L.) yield and subsequent soil health are largely unknown. A 4‐yr field study was conducted to determine the effect of winter wheat (Triticum aestivum L.) cover crop and PL on cotton lint yield in narrow (0.75 m) and conventional (1.01 m) row spacings. The experimental design was split‐split plot with three replications. The cover crop treatment was assigned to the main plots. Within the cover crop treatment, a narrow row spacing compared to conventional row spacing as subplots. Fertilization treatments included unfertilized control, inorganic N fertilizer (112 kg N ha−1) and PL (6.7 Mg ha−1). Lint yield was significantly greater with PL than inorganic fertilizer each year. Lint yield in a dry season was significantly greater with cover crop treatment. However, following the cessation of PL in 2017, lint yield increased by 12% in the absence of cover crop residue. As compared to unfertilized control, applying PL in the presence of cover crop residue enhanced soil C by 22% and water aggregate stability by 7.4% and reduced soil penetration resistance and bulk density by 9 and 3.5%, respectively. Applying PL for 3 years increased soil levels of both gram‐negative bacteria, 16S rRNA, and ureC, while planting cover crop doubled heterotrophic plate count bacteria. Integration of PL and cover crop residue in a no‐till cotton increased lint yield and improved soil quality indicators.

Skip row planting configuration shifts grain sorghum water use under dry conditions

Grain sorghum (Sorghum bicolor L. [Moench]) is grown as a dryland crop in the semi-arid Central Great Plains. Growing the crop in a skip row configuration has been proposed as a means of delaying water use during the vegetative stage such that more water will be available to be used during the more critical flowering and grain filling stages, thereby improving yield under water stress conditions. The objective of this study was to determine if grain sorghum grown in a skip row configuration used water differently than sorghum grown in conventionally spaced rows. Grain sorghum was grown for three years at Akron, CO in three planting configurations: conventionally spaced rows 0.76 m apart, one row planted and one row skipped (P1S1), and two rows planted and two rows skipped (P2S2). Each planting configuration was planted at two seeding rates. Soil water was measured at several distances from the planted row at planting, flowering, and physiological maturity. Soil water depletion and water use were not affected by seeding rate. Grain sorghum was found to extract water at distances of 114 cm from the planted row. When growing season conditions were dry and starting soil water contents were low, skip row planting shifted the water use such that greater water use was seen during the second half of the growing season than with the conventionally spaced planting. These results support the observation of greater sorghum yields with skip row planting than with conventional row spacing during dry growing seasons.Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for com-munication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Direc-tor, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

Effects of Tillage and Planting Methods on Narrow and Wide Row Cotton Production

Cotton (Gossypium hirsutum L.) is an economically important crop for the Southern United States. The southern US also has a long growing season suitable for double cropping a second crop after small grains; however, the harvest date for the small grains typically occurs after the optimum planting window for cotton which reduces yield potential. A relay intercropping system was developed at Clemson University that allows interseeding of cotton into standing wheat 2 to 3 weeks before harvest with interseeded cotton yields similar to the conventional mono-cropped cotton. Therefore, the objectives of this study were 1) to determine the optimum tillage and planting methods for narrow row (76-cm) and wide row (97-cm) cotton, and 2) to compare narrow and wide row systems for conventional tillage cotton, cotton interseeded into standing wheat, and cotton planted into a terminated wheat cover crop on coastal plain soil. Two replicated tests were conducted to accomplish these objectives. In Study 1, conventional narrow row cotton combined with a deep tillage operation using Paratill yielded 23% more than conventional wide row cotton which had a deep tillage operation with a subsoiler just before planting. There were no differences between the conventional (97-cm row spacing) mono-crop and interseeded cotton yields. In Study 2, there was no significant difference in yield between narrow-row and wide-row cotton for each cropping system during the two years study. Both wide and narrow-row full season cotton had significantly higher yields than interseeded and cover crop planting systems in year two of the study. The two conservation cropping practices, wheat used as a cover crop and interseeding, showed considerable promise for reducing energy requirements, soil erosion, and wind-borne cotton damage associated with bare soil in conventional tillage. This research demonstrates the benefits of interseeding and narrow row spacing for sustainable cotton production in coastal plain soils of the Southern United States.

Anomaly free search using multi table entity attribute value data model

In this paper, the authors are proposing a principled extension of dynamic tables (DT). It is termed multi table entity attribute value (MTEAV) model which offers a search efficient avenue for storing database. The authors present precise semantics of MTEAV and demonstrate the following: 1) MTEAV possesses consistency and availability; 2) MTEAV outperforms other existing models (entity attribute value model, dynamic tables, optimised entity attribute value and optimised column oriented model) under various query scenarios and varying datasets size; 3) MTEAV retains flavour of EAV in terms of handling sparseness and self-adapting schema changing capability. To heighten adaptability of MTEAV, authors implement a translation layer over existing SQL engine in a non-intrusive way. Translation layer transforms conventional SQL query (as per horizontal row representation) to a new SQL query (as per MTEAV structure) to maintain user friendliness. Translation layer makes user feel as if he/she is interacting with the conventional horizontal row approach. The authors also critically analyse maximum percentage of non-null density appropriate for choosing MTEAV as a storage option.

Planting Geometry Effects on the Growth and Yield of Dryland Cotton

The declining Ogallala Aquifer beneath the Southern High Plains may necessitate dryland crop production and cotton (Gossypium hirsutum L.) is a well-adapted and potentially profitable alternative crop. The limited growing season duration of the Texas Panhandle and southwestern Kansas, however, imposes significant production risk due to incomplete boll maturation. Emphasizing earlier boll production that is usually confined to sites on lower fruiting branches may reduce risk, but offsetting high planting densities are needed to maintain desirable lint yield. Our objectives were to quantify planting: 1) row width and 2) in-row spacing effects on growth, yield, and fiber quality of dryland cotton. Field tests of row widths from 0.25 to 0.76 m and plant densities with in-row spacing ranging from 0.075 to 0.15 m were conducted from 1999 to 2005 on a nearly level Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) managed in a wheat (Triticum aestivum L.), cotton, fallow (W-Ctn-F) rotation. To expand the basis of comparison, cotton growth and yields were simulated using GOSSYM and long-term (1958-2000) weather records from Bushland, TX, as input for all combinations of 0.38 or 0.76 m row widths and plant spacing of 0.075, 0.10 and 0.15 m. Experimental and computer simulated plant height and harvested boll number increased significantly with increased row spacing and, occasionally, in-row plant spacing. Modeled lint yield for 0.38 m rows decreased by approximately 50% compared with the 582 kg·ha-1 yield for conventional row spacing, which was practically duplicated by field observations in 2001 and 2004. Measured fiber quality occasionally improved with conventional row spacing over ultra-narrow rows, but was unaffected by plant spacing. Because narrow rows and frequent plant spacing did not improve lint yield or fiber quality of dryland cotton, we do not recommend this strategy to overcome a thermally limited growing season.

Group planting of cherry (Prunus avium L.) fosters growth and tree quality is superior to conventional row planting in Germany

Wild cherry trees produce high-quality timber and provide multiple ecosystem services. However, planting and tending cherry stands in conventional rows are too costly. Therefore, low density group planting was trialled as an alternative to row planting. The mortality, growth, and quality of planted cherry trees were compared between the group and row planting. The influence of neighbourhood competition and light availability on growth and quality was studied. The group and row planting of cherry trees were established at a wind-thrown site in southwestern Germany in the year 2000. In group planting, five cherry seedlings and seven lime seedlings (Tilia cordata Mill.) were planted with a 1 × 1 m spacing. In total, 60 groups were planted per hectare with a 13 × 13 m spacing. In contrast, 3300 seedlings (2475 cherries and 825 limes) were planted per hectare in row planting with a 3 × 1 m spacing. Ten groups and plots (10 × 10 m) were randomly established in group and row planting stand, respectively. The survival rate, stability (height to diameter ratio), diameter, and height growth were significantly higher in group planting. In the group plantings, 40.5% of cherry trees had straight stems and 13.5% had a monopodial crown compared with 15% with straight stems and 2% with a monopodial crown in row planting. The proportion of dominant cherry trees in canopy was 49% in groups compared with 22% in rows. The length of branch free bole was significantly higher in cherries planted in groups than those grown in rows. Intra- and interspecific competition reduced the growth and stability of cherry trees in row planting, but not in group planting. Light availability did not cause any significant effects on growth and quality between group and row planting. This first study on cherry group planting indicates that the survival rate, growth, and tree quality were higher in groups than in rows at this early development stage. The competition by naturally born seedlings was an important reason for the difference in performance between group and row planting. This study will encourage forest practitioners to establish more cherry group planting trials on multiple sites to test the effectiveness of this alternative technique as a tool of regeneration and restoration silviculture.

<b>Effect of foliar fungicide and plant spacing on the expression of lipoxygenase enzyme and grain rot in maize hybrids

This study was carried out with the objective of evaluating the effect of fungicide application on grain rot in commercial maize hybrids and the relation between grain rot and the expression of lipoxygenase enzyme in grain in conventional row spacing of 0.70 m and reduced row spacing of 0.45 m. Treatments were made in a 3 x 8 factorial scheme, using three forms of management with fungicide (Trifloxystrobin + Prothioconazole) and eight maize hybrids divided into two groups (tolerant and susceptible) with three repetitions, totaling 72 plots in each environment (conventional and reduced spacing) in the 2013/2014 crop. The following characteristics were evaluated: grain rot percentage and lipoxygenase enzyme expression (LOX) in the grain. The hybrid and the fungicide utilized influenced the grain rot percentage. Grain rot percentage was reduced by the use of the fungicide, and the highest reduction was in susceptible hybrids with two applications, V8 and V8+VT. There was higher expression of LOX enzyme in maize hybrids that belong to the group tolerant of fungi that cause grain rot .The use of the fungicide in two applications, V8 (eight leaves) and VT (tasseling), increased the intensity of the LOX enzyme, which was more evident for the reduced spacing.

Growing sweet sorghum (Sorghum bicolor [L.] moench) in clumps potentially reduces lodging in the arid-southwestern United States

Sweet sorghum (Sorghum bicolor [L.] Moench) is an attractive crop for the biofuel industry in the arid-southwestern United States due to its high yields of fermentable juice as well as fibrous biomass, with lower water requirements and high water use efficiency. Previous work has shown that when planted closer together the resulting stalks are thinner, weigh less, yield less juice, and are more susceptible to lodging, thus affecting yields. The studies examined the effects of planting sweet sorghum in clumps (three to five plants in a hill, spaced 0.5m apart) compared to conventional rows (planted equidistant with a grain drill).Four varieties (Cowley, Hodo, M81E, and Mer74-2) were sown on 6 June 2014 and 26 May 2015 in a split-plot design, with arrangement (clump or conventional) as main plot and variety as sub-plot, with five replications in 2014 and four in 2015. Conventional rows were planted with a tractor-driven grain drill at 18 seeds m−1. Clumps were hand-planted as a cluster of three to five seed in a single hole every 0.5m. Harvest commenced 30days after half of the plants in a variety were flowering. A 3.05m section was harvested, and weighed. A subsample of plants was weighed with or without leaves and panicles, stem diameters measured, the stalks pressed, and juice collected and weighed. Sugars in the juice samples were analyzed by HPLC with a refractive index detector.Individual stems in the clumps were significantly greater in diameter and weight, although field weight showed no significant difference between treatments. Plants in conventional rows were smaller but there were more of them per area than the clump treatments. There were no differences in number of leaves, but the overall leaf weight was significantly greater in the clump treatments, due to increased leaf width and area, but not length. Lodging was significantly lower in the clump treatments in 2015, indicating that the thicker stalks are less susceptible to lodging.Planting sweet sorghum in clumps resulted in thicker, sturdier stalks with more juice, and did not decrease yields over conventionally planted plots. Planting in clumps has potential under irrigation in the arid southwestern United States to increase yields.

Potential of global croplands and bioenergy crops for climate change mitigation through deployment for enhanced weathering

Conventional row crop agriculture for both food and fuel is a source of carbon dioxide (CO2) and nitrous oxide (N2O) to the atmosphere, and intensifying production on agricultural land increases the potential for soil C loss and soil acidification due to fertilizer use. Enhanced weathering (EW) in agricultural soils-applying crushed silicate rock as a soil amendment-is a method for combating global climate change while increasing nutrient availability to plants. EW uses land that is already producing food and fuel to sequester carbon (C), and reduces N2O loss through pH buffering. As biofuel use increases, EW in bioenergy crops offers the opportunity to sequester CO2 while reducing fossil fuel combustion. Uncertainties remain in the long-term effects and global implications of large-scale efforts to directly manipulate Earth's atmospheric CO2 composition, but EW in agricultural lands is an opportunity to employ these soils to sequester atmospheric C while benefitting crop production and the global climate.

Activity, diversity and function of arbuscular mycorrhizae vary with changes in agricultural management intensity

Many beneficial soil microbes are sensitive to chemical and mechanical disturbances associated with conventional row crop agriculture, including arbuscular mycorrhizal (AM) fungi. AM fungi provide agricultural benefits through multiple mechanisms including increasing crop pathogen resistance, helping with crop nutrient acquisition, and increasing soil carbon storage. Conversion to less intensive row crop agricultural management systems such as biologically-based organic and no-till may reduce the negative effects of conventional management to AM fungi. In this study, AM fungus activity (via glomalin production), spore diversity, community structure, and community stability were surveyed over 20 years in no-till, biologically-based organic, and conventionally managed plots at the W.K. Kellogg Biological Station Long Term Ecological Research Site in Michigan, USA. A complementary greenhouse experiment tested for direct effects of AM fungal inocula from these different agricultural management treatments on growth of corn and wheat plants. Soil glomalin increased in no-till and organic management systems, most likely due to decreases in disturbance associated with tillage and chemical inputs. No-till management slightly increased AM fungus diversity and community stability. AM fungus community structure significantly differed between conventional and no-till treatments, with an indicator species analysis showing that Acaulospora spp. were characteristic of conventional management, while Glomus spp. and Gigaspora spp. were associated with no-till management. AM fungal inocula from organically-managed treatments increased wheat, but not corn, growth. Overall, conversion from long-term conventional row crop agricultural management to no-till or biologically-based organic systems increased soil glomalin, but did not uniformly improve AM fungus diversity or crop plant benefits. In the future, novel agricultural systems combining organic management with conservation tillage may further improve AM fungal benefits to soils and crops.

A model for evaluating production and environmental performance of kenaf in rotation with conventional row crops

The potential inclusion of kenaf (Hibiscus cannabinus L.) into the conventional corn (Zea mays L.) and soybean (Glycine max L.) rotation of the U.S. Midwest requires investigation. A new kenaf model within the Agricultural Production Systems Simulator (APSIM) was developed and subsequently used to address questions needed for decision making: 1) what is the optimum planting date of kenaf under water-nitrogen limited and non-limited conditions in central Iowa; 2) does soil nitrate accumulation vary among kenaf, corn, and soybean crops?; 3) is soil organic matter (SOC) influenced in the long term?; and 4) how do kenaf water use efficiency (WUE) and nitrogen use efficiency (NUE) compare to corn and soybean? The model indicated that simulated optimum planting date for maximizing kenaf production ranged from April 15 to June 1. Model analysis of different rotation systems showed that there was a slight tradeoff between kenaf stem biomass and soybean yield. Long term soil organic carbon simulations (30 years) indicated a slight decrease over time while inclusion of kenaf in the corn-soybean (C-S) rotation did not affect this trend. In conclusion, this study brings to the scientific literature a new kenaf model that provided information that was missing for decision support.