Narrow Row Spacing Research Articles

On-farm evaluation of UAV-based aerial imagery for season-long weed monitoring under contrasting management and pedoclimatic conditions in wheat

Timely availability of weed infestation maps is a key prerequisite for the implementation of site-specific weed management practices. Low-altitude aerial imagery obtained from unmanned aerial vehicles (UAVs) has shown significant potential for weed detection in crops. However, most studies focused on wide-spaced row crops such as maize and sunflower and evaluated proposed methods on single or few well-characterized experimental sites at specific points in time representing a limited range of application scenarios. This study evaluated the feasibility of weed detection in on-farm wheat fields characterized by a narrow row spacing, throughout the early and late developmental stages using UAV imagery and ground-based high-resolution imagery. Image data was obtained for nine sites, representing a wide range of management and pedoclimatic conditions. These sites can be seen as a representative sample of scenarios that would be encountered in practice. A high within- and across-site as well as temporal variation was observed for weed infestation levels and weed population species composition, highlighting the need for spatially and temporally resolved weed mapping. Image-based classification of vegetation objects as crop or weed plants was achieved with an accuracy of 0.88 and 0.72 in ground-based high-resolution images and UAV-based aerial images captured from an altitude of 10 m, respectively. The accuracy of pixel-wise, vegetation-index-based weed infestation estimation during the late vegetative stages varied strongly across sites. Our results highlight the critical importance of a high ground resolution for weed detection using object-based image analysis during the critical growth stages of wheat and of robust methods that are applicable across a range of scenarios. This suggested that future research aiming at a rapid implementation of site-specific weed management in wheat should focus on the development of ground-based systems. Yet, aerial monitoring of wheat stands during late developmental stages using currently available equipment offers significant potential for reducing weed pressure with site-specific weed control measures in the context of crop rotations.

Winter Wheat Seeding Decisions for Improved Grain Yield and Yield Components

The continual re-evaluation of agronomic practices is necessary to improve crop performance and sustainability of the production of winter wheat (Triticum aestivum L.), particularly as genetics and climate conditions change. Recommendations made about winter wheat planting dates, spacing, variety, and seed rates under normal climatic conditions may not be suitable in current times with more climate variability. Our experiment investigated the effect of planting date (early, historic-optimum, and late), row spacing (19 and 25 cm), variety (Goodstreak, Robidoux, and Wesley), and seed rate (1.8, 2.1, 2.3, 2.4, 2.6, 2.8, 3.1, and 3.4 M seeds ha−1) on winter wheat grain yield and yield components. The seeding rate was nested within row spacing in nested-factorial design. A nested-factorial treatment design was used with testing at several locations in Nebraska across two years. Variety had a substantial effect on winter wheat grain yield (p < 0.05). Variety also had a substantial interaction effect with planting date and row spacing 50% of the time (p ≤ 0.01). At Hemingford, for example, Wesley planted at 19 cm had 5.9% more yield when compared to Robidoux planted at 19 cm (5.5 Mg ha−1). Similarly, biomass was influenced by variety across sites (p < 0.01), but a substantial interaction effect also occurred between planting date and variety at two of the three sites. Narrow row spacing (19 cm) led to significantly more tillers (6.9 M ha−1) when planted with Goodstreak at two of the sites. While planting date by itself did not affect any of the responses evaluated, this research highlights the importance of comprehensive and holistic approaches to wheat production in the High Plains.

Effect of Variation in Row Spacing on Soil Wind Erosion, Soil Properties, and Cyperus esculentus Yield in Sandy Land

Cyperus esculentus is highly adaptable to extremely arid conditions and functions of oil extraction and sand fixation. Numerous studies have investigated the influence of row spacing on traditional crop growth and soil physicochemical traits but have not determined how cultivation affects C. esculentus growth and soil properties. Therefore, we conducted a field experiment in a sandy land to explore the responses of the organ yields of C. esculentus, soil wind erosion, and soil properties to row spacing (30, 60, or 90 cm), and bare land was used as the control. The highest plant height, plant density, number of tillers, and organ yields were observed at 30 cm row spacing. However, the lowest degree of soil erosion was also observed at 30 cm row spacing, and the coverage of C. esculentus facilitated soil fixation and conservation. The levels of soil wind erosion in the control plot were 11.7, 3.1, and 4.9 times those at 30, 60, and 90 cm row spacing, respectively. The percentages of clay and silt increased, whereas sand particles decreased with decreasing levels of soil wind erosion. Soil texture improved, and soil nutrients and plant growth were altered. Soil nutrient concentrations, yields, and root nutrient concentrations were positively related to clay percentage and negatively related to sand particles. In addition, the microbial biomass carbon and nitrogen significantly increased in the C. esculentus treatment groups, suggesting that planting C. esculentus promotes the survival and development of microorganisms. Overall, this study indicated that planting C. esculentus can decrease the level of soil wind erosion and improve soil quality. Narrow row spacing (30 cm) has the highest crop yield and soil amelioration and produces optimal ecological and economic benefits.

Effects of Mechanical Transplanting Methods and Planting Geometry on Yield Formation and Canopy Structure of Indica Rice under Rice-Crayfish Rotation

The rice–crayfish continuous production system developed rapidly due to its high economic benefits and eco-friendly nature in China. This study explored the effects of mechanically transplanted methods and planting geometry on the relationship between rice yield and canopy structure, under rice-crayfish rotation using excellent-quality indica rice, and carried out in 2018 and 2019. Three mechanical transplantation methods were set as follows: carpet seedlings mechanically transplanted with 30 cm equal row spacing (CMTE), pot seedlings mechanically transplanted with narrow row spacing with alternating 23 cm/33 cm wide row spacing (PMTWN), and equal row spacing at 28 cm (PMTE). Different plant spacings (CMTE1-CMTE6, PMTWN1-PMTWN6, PMTE3, and PMTE4) were set in accordance with different mechanical transplanting methods. CMTE and PMTWN both included six transplanting densities, while PMTE included 2 transplanting densities. Results showed that rice yield was improved by 2.87–6.59% under PMTWN when compared to CMTE, which was mainly due to the increase in spikelets per panicle and filled-grain percentage. Dry matter accumulation was increased and larger leaf area indexes were observed under PMTWN than CMTE at the rice main growth stage. Yield of CMTE and PMTWN treatments increased at first and then declined with decreased planting density. Under suitable planting density, PMTWN could optimize rice population structure and increase rice yield compared with PMTE. For tested rice variety, pot seedlings were mechanically transplanted alternating alternating 23 cm/33 cm wide row spacing, combined with a plant spacing of 16.8 cm, was proper for its yield improvement under rice-crayfish rotation.

Appropriate bandwidth achieves a high yield by reducing maize intraspecific competition in additive maize–soybean strip intercropping

Maize–soybean strip intercropping can effectively alleviate arable land competition, improve land output, and be conducive to the sustainable development. The key to achieve these advantages is to stabilize the maize yield. Suitable narrow row spacing could maximize the benefit of maize–soybean strip intercropping, and an increasing bandwidth with suitable narrow row spacing is beneficial to the mechanized production of soybean. In practice, to ensure the maize yield in additive maize strip intercropping, maize plant spacing decreases and intraspecific competition intensifies as the bandwidth increases. However, interspecific interactions have been the primary focus of studies because of the better rhizosphere nitrogen fixation ability of soybean and the activation of maize rhizosphere nutrients. Therefore, it is particularly urgent to identify the trade-offs between intraspecific competition and interspecific interactions in maize and the regulatory effects on maize yield. Field experiments were conducted from 2017 to 2020 to analyze the results of interindividual competition in maize and interactions with soybeans under different bandwidths. It was found that maize biomass and yield at the maturity stage decreased by 8.0% and 6.4%; 20.5% and 19.4%; and 28.7% and 44.1% from 2 m to 2.8 m, respectively, but the biomass proportion in ears showed no significant difference. Intraspecific competition of maize was weakened by special promotion in intercropping, but stable yield was achieved only at 2 m. In response to suitable competition, maize roots can flourish only on the basis of ensuring aboveground biomass. The results revealed that the primary negative determinant of maize yield was intraspecific aboveground competition and strengthening intraspecific competition reduced biomass accumulation without altering the allocation ratio to the ear. We concluded that maize yield was guaranteed at 2 m due to the special strip planting design compensated for the enhanced intraspecific competition of maize aboveground parts in the additive maize–soybean strip intercropping system.

Identification of agro-physiological traits of lentil that reduce risks of drought.

Ideotype breeding is an essential approach for selection of desired combination of plant traits for testing in crop growth model for potential yield gain in specific environments and management practices. Here we parameterized plant traits for untested lentil cultivars for the APSIM-lentil model in phenology, biomass, and seed yield. We then tested these against independent data and applied the model in an extrapolated analysis (i) to assess the impact of drought on productivity across different rainfall environments; (ii) to identify impactful plant traits and (iii) to design new lentil ideotypes with a combination of desirable traits that mitigate the impact of drought, in the context of various agronomic practices across a wide range of production environments. Desirable phenological and physiological traits related to yield were identified with RUE having the greatest effect on yield followed by HI rate. Leaf size significantly affected seed yield (p< 0.05) more than phenological phases. The physiological traits were integrated into four ideotype designs applied to two baseline cultivars (PBA Hallmark XT and PBA Jumbo2) providing eight ideotypes. We identified a combination of genetic traits that promises a yield advantage of around 10% against our current cultivars PBA Hallmark XT and PBA Jumbo2. Under drought conditions, our ideotypes achieved 5 to 25% yield advantages without stubble and 20 to 40% yield advantages with stubble residues. This shows the importance of genetic screening under realistic production conditions (e.g., stubble retention in particular environments). Such screening is aided by the employment of biophysical models that incorporate both genetic and agronomic variables that focus on successful traits in combination, to reduce the impact of drought in the development of new cultivars for various environments. Stubble retention was found to be a major agronomic contributor to high yield in water-limiting environments and this contribution declined with increasing growing season rainfall. In mid- and high-rainfall environments, the key drivers of yield were time of sowing, physiological traits and soil type. Overall, the agronomic practices, namely, early sowing, residue retention and narrow row spacing deceased the impact of drought when combined with improved physiological traits of the ideotypes based on long term climate data.

Effects of Row Spacing and Planting Pattern on Photosynthesis, Chlorophyll Fluorescence, and Related Enzyme Activities of Maize Ear Leaf in Maize–Soybean Intercropping

With the continuous improvement of the mechanization level and the development of new crop varieties, the optimal strip width for intercropping crops is important. In this study, field experiments were conducted to analyze the effects of different row spacings and planting patterns on photosynthesis, chlorophyll fluorescence, and the related enzyme activities of maize ear leaves in a maize–soybean intercropping system using two planting patterns (wide–narrow rows of 80–50 cm and uniform ridges of 65 cm) and two intercropping ratios (four rows of maize and four rows of soybean; six rows of maize and six rows of soybean). The results showed that the pattern of wide–narrow-row spacing significantly improved the photosynthetic capacity of maize compared with the uniform-ridge planting pattern, along with marked elevation in the values of stomatal conductance (Gs), the transpiration rate (Tr), and the photosynthetic rate (Pn). On the other hand, the values of photochemical quenching (qP), actual photochemical efficiency (φPSII), and maximum photochemical efficiency (Fv/Fm) also significantly increased, and the effect of D-M6S6 treatment was the most significant on these parameters. Similarly, the activities of phosphoenolpyruvate carboxylase and ribulose-1,5-bisphosphate carboxylase/oxygenase also increased significantly. Among different treatments, the yield under the D-M6S6 treatment was the highest. Therefore, based on the planting pattern of the wide–narrow-row spacing, the intercropping of six rows of maize and six rows of soybean is the better design in the semi-arid regions of western China.

Effects of row spacing on soil nitrogen availability, wheat morpho-physiological traits and radiation use efficiency

Optimizing row spacing is an important measure to exploit the full yield potential, achieve a continuous increase in wheat yield and green development without increasing input. The objective of this study was to compare the effects of wide–narrow row spacing pattern (12 cm-12 cm-12 cm-24 cm, R1) and conventional uniform row spacing mode (20 cm, CK; 12 cm. R2) on nitrogen (N) availability in soil, canopy structure, photosynthetic characteristics, radiation use efficiency (RUE) and yield. The results showed that R1 increased the relative abundance of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in the rhizosphere compared to CK. Nitrate in soils treated R1 at post-anthesis and nitrogen use efficiency of the plant were 59.92% and 27.01% higher than those treated with CK, respectively. Above-ground growth of wheat showed that R1 increased leaf area index by 27.42%, specific leaf weight by 22.67% and leaf photosynthetic rate by 8.86%, respectively compared to CK. R2 had similar availability of N and plant growth as CK. Moreover, the ability of the plant to allocate more nitrogen to grains was enhanced at post-anthesis with R1 than it with CK and R2, which greatly improved the RUE by 10.13% and 2.27%. As the result, the yield for R1 increased by 27.54% and 21.46%, respectively, compared to CK and R2. Therefore, using wide–narrow row spacing pattern (R1) is a practically and environmentally feasible approach for wheat production without extra input in the straw-returning wheat-corn rotation system.

The Influence of Different Row Spacing and Weed Control Intervals on Weed Infestation and Yield-Related Traits of American (Gossypium hirsutum L.) and Desi (Gossypium arboreum) Cotton

Narrow row spacing has attracted significant attention due to its beneficial impacts on weed management in cotton. This study compared the effects of normal and ultra-narrow row spacing on critical periods of weed control in American (Gossypium hirsutum L.) and ‘Desi’ (Gossypium arboreum) cotton. Two different row spacings (i.e., recommended (75 cm) and ultra-narrow (30 cm)) and three weed control intervals (i.e., weed control at 30, 60 and 90 days after sowing (DAS)) were included in the study. Weedy-check and weed-free treatments were included in the experiment as controls for comparison. ‘Desi’ cotton grown under ultra-narrow spacing recorded the lowest weed density and individual density of Trianthema portulacastarum L., Cyperus rotundus L., Cynodon dactylon L., Echinochloa colona (L.) Link and Digera muricata (L.) Mart. Moreover, ‘Desi’ cotton sown under ultra-narrow spacing with weed-free and weed control at 30 DAS resulted in the highest leaf area index (LAI), leaf area duration (LAD), net assimilation late (NAR), root elongation rate (RER) and root growth rate (RGR) at all sampling dates. Likewise, ‘desi’ cotton sown under recommended row spacing and weed-free conditions produced the highest number of sympodial and monopodial branches, number of flowers and bolls per plant, whereas the highest seed cotton yield of ‘Desi’ cotton was noted under ultra-narrow spacing and weed-free conditions. It is concluded that sowing both cotton types in ultra-narrow row spacing and controlling weeds at 30 DAS will result in lower weed infestation and higher seed cotton yield.

Soybean cultivars subjected to narrow row spacing and plant populations in early sowing in subtropical region in southern Brazil

Spatial arrangement between plants and sowing time used are decisive practices for obtaining adequate agronomic performance in soybean crop. The aim of this work was to evaluate morphological attributes, yield components and grain yield of soybean cultivars installed with different row spacing and seeding densities, in early (10/04/2017) and conventional (11/08/2017) sowing dates in subtropical climate region in southern Brazil. The experimental design was in a 2×2×4 factorial arrangement: soybean cultivars BRS 433 RR (MG 5.8) and BRS 1003 IPRO (MG 6.3) installed with row spacing of 25 and 50 cm and seeding densities of 160,000; 240,000; 320,000; and 400,000 viable seeds ha-1. Morphological attributes and yield components are altered by spatial arrangement between plants and cultivar, with variable responses according to the sowing date. In the early sowing date, soybean has yield raise due to the increase in seeding density with different responses between cultivars. In the conventional sowing date, soybean installed with 25-cm row spacing has an increase in 1000-grains weight. In the conventional sowing date, there is an increase in soybean yield installed with 25-cm row spacing associated with a seeding density of 320,000 to 400,000 viable seeds ha-1.

Effect of Different Seed Rates and Row Spacing on Yield Attributes and Yield of Late Sown Wheat (Triticum aestivum L.)

Background: Wheat (Triticum aestivum L.) is the most important cereal crop throughout India and other parts of the world. In late sowing conditions the variety selection, seed rate and row spacing is an important factor for a better crop yield. Higher seed rate and narrow row spacing are used in late sowing as compared to normal sowing conditions. Methods: The present field experiment was conducted at the Students Research Farm, Khalsa College, Amritsar, Punjab, India during rabi season of 2020-21. A field experiment was laid out in split-plot design with replicated three times comprising four levels of seed rate viz. (100, 110, 120 and 130 kg/ha) and three-row spacing viz. (12, 15 and 18 cm) of wheat cultivar DBW 187 (Karan Vandana). Result: The result showed that the number of tiller per meter, spike length, grains per spike, test weight, grain, straw and biological yield were significantly affected by different seed rates and row spacing. The seed rate 120 kg/ha recorded significantly higher grain yield (50.47 q/ha), effective tiller per meter row length (70) and the number of grain per spike (58), whereas 130 kg/ha gave significantly higher straw yield (73.40 q/ha). The crop sown with row spacing 18 cm showed significantly higher grain yield (49.13 q/ha), straw yield (72.70 q/ha), biological yield (121.83 q/ha), effective tiller per meter row length (68), spike length (12.10 cm) and number of grain per spike (56.16).

Effects of Different Row Spacing and Seeding Rate on Seed Yield and Some Yield Components of Birdsfoot Trefoil (Lotus corniculatus L.) in Tokat Region.

Birdsfoot trefoil (Lotus corniculatus L.); is an considerable component of natural range and grassland, besides producing sufficient forage in environmentally restricted fields. In order to for increase birdsfoot trefoil cultivation, it is necessary to the sufficient quantity produce quality seeds. The information regarding the row spacing and seeding rate is important for achieving yield targets and better economic returns of birdsfoot trefoil. Our field study was carried out in order to determine the optimum row spacing and seeding rate for seed production of Sarıyıldız 60 variety that new registrated in the semi-arid climate conditions of the Central Black Sea transition zone, where this plant was not grown before. The field experiment was conducted at the using a randomized complete block split-plot design with three replicates in 2017 to 2019 growing seasons. The study were tested four different (20,40, 60 and 80 cm) row spacings and (5, 10, 15 and 20 kg-ha-1) seeding rates. Results of connectedly analysis showed that row spacing and seeding rate aplication on that the effect of on seed yield and number of pods per plant, 1000 seed weight was significant statistically but didn’t have any significant effect on number of seed per pod and harvest index. The interaction between row spacing and seedin rate did not show any significant statistical be different on seed yield and yield components. In general accepted, the number of pods per plant, the number of seeds per pod, the weight of thousand seeds and the harvest index decreases with the increase in the seed rate in all row spacings. Results showed that seed yield increases with narrower row spacing. The mean data from the three years experimental showed that the highest seed yield was obtained with plants grown in 40-20 cm row spacing’s at a seeding rate of 10-15 kg-ha-1 (24.8 and 25.7 kg per ha in respectively).

Integrated agronomy for high yield and stable flax production in Canada

AbstractIntegrating agronomic practices can be useful in increasing flax (Linum usitatissimum L.) yield under biotic or abiotic constraints. A study was conducted to determine the combined effect of seeding density, row spacing, fertilizer, and fungicide application on no‐till flax yields at three locations (7 site‐years) in Saskatchewan and Manitoba, Canada. The four treatments were plant density; low (190 plants m–2) vs. moderate (320 plants m–2), row spacing; narrow (20 cm) vs. wide‐row (40 cm), N rate; 65 vs. 130% of soil test recommendation, and foliar fungicide; pyraclostrobin + fluxapyroxad vs. no fungicide. No individual treatment parameter significantly affected yield; however, several combinations of treatments did. The combination of moderate density, narrow row spacing, 130% N, and fungicide application showed a 23% mean yield increase across all environments compared with the lowest‐yielding combination. Still, yield ranking differed across different growing environments. The overall high‐yielding combination was not productive under low‐yielding environments. The same high‐yielding combination, but with wide row spacing and the same combination with low density provided the most stable and moderate yield across all environments tested. Considering seed cost, yield advantage, and yield stability, the best combination was low density, narrow row spacing with 130% N and fungicide application. Among all practices, the combined application of 130% N and fungicide application significantly increased crop yield by 11% under all growing conditions. In the absence of negative interactions, producers can combine these four practices to increase flax yields depending on the cost.

Weed Management in Direct Seeded Rice under Different Row Spacing

A field study to evaluate the weed management in direct seeded rice under different row spacing was carried out at Agronomic Research Area, University of Agriculture, Faisalabad during summer 2018. Two herbicides Butachlor @ 118.61 g a.i. ha-1 (pre-emergence) was applied within 24 hours of sowing of direct seeded rice and combination of two herbicides Butachlor @ 118.61 g a.i. ha-1 (pre-emergence) within 24 hours after sowing sequentially followed by Bispyribac Sodium + Bensulfurin Methyl @ 26.7 g a.i. ha-1 + 17.8 g a.i. ha-1 (post-emergence) was applied 15 days after sowing. Bispyribac Sodium @ 26.7 g a.i. ha-1 was applied 15 days after sowing. A weedy check and weed free treatment were also run for comparison. A fine rice cultivar (Basmati 515) was sown during the last week of June in 22.5 cm and 11.25 cm spaced rows using a seed rate of 29 kg ha-1. To fulfill the requirement of nutrients 135 kg N, 88 kg P and 61 kg ha-1 K were applied. The experiment was replicated thrice in a randomized complete block design under split plot arrangement. The net plot size was 3 m × 2.25 m. Date regarding weed density (15, 30 and 45 DAS), weed biomass before harvesting and yield components of rice were recorded by following standard procedures and statistically analyzed by applying Fisher’s analysis of variance technique. Least significant difference test (LSD) at 5% probability was used to compare treatments means. Results of the study showed that total weed density and weed dry weight were significantly influenced by different row spacing and weed control treatments. Significantly lower weed density and weed biomass were observed under narrow row spacing (11.25 cm) as compared to wider row spacing (22.5 cm). Among weed control treatments application of Butachlor @ 118.61 g a.i. ha-1 (pre-emergence) within 24 hrs after sowing of DSR and Bispyribac Sodium @ 26.7 g a.i. ha-1 (15 DAS) reduced the total weed density and weed dry weight. Similarly, paddy yield was also significantly influenced by different row spacing and weed control treatments as weed free at 11.25 cm row spacing gave maximum paddy yield (4.0 t ha-1).

Effect of Plant Spacing on Agronomic Performance and Fodder Quality of Four Tepary Bean (Phaseolus acutifolius A. Gray) Cultivars

Tepary bean is gaining interest around the world as a dryland field crop. A two-year field experiment was conducted to determine the effect of plant spacing on the agronomic performance and fodder quality of the crop. A split-plot design was used with three replications, four cultivars (GK010, GK011, GK012, and Motsumi) were assigned to main plots, while subplots were three intrarow plant spacing (10 cm, 20 cm, and 30 cm). Four agronomic variables and eight chemical compositions, including in vitro dry matter digestibility (IVDMD) of husk, stem, and leaf, were measured. Spacing significantly ( P &lt; 0.05 ) influenced plant biomass, pod yield, harvest index, and seed yield, while cultivar affected only pod yield and seed yield. Plant biomass increased with plant spacing where 10 cm produced 936 kg/ha; 20 cm, 750 kg/ha; and 30 cm, 611 kg/ha for 2015–2016 while 10, 20, and 30 cm were observed for 1568 kg/ha, 1135 kg/ha, and 889 kg/ha, respectively, in 2016–2017 season. These trends are attributed to the higher plant population in the narrow row spacing. GK012 consistently outperformed other cultivars for plant biomass, pod yield, and seed yield and has a potential for further selection. Fodder nutritive qualities were not affected by cultivar, while spacing only influenced IVDMD. The three plant parts were significantly ( P &lt; 0.05 ) different for all the nutritive qualities. Leaves had significantly ( P &lt; 0.05 ) lower values of ADF, CF, and NDF compared to those of stem and husk an indication of relatively higher digestibility of the leaf. Acid detergent fiber (40%), neutral detergent fiber (53.65%), crude fiber (35.45%), ash content (12.29%), dry matter (93.09%), and IVDMD (70.66%) were recorded. This study revealed that tepary bean forage has good nutritional content, except for the low phosphorus level. For higher agronomic performance, tepary cultivars should be planted at a spacing of 10 cm without compromising forage quality.

A Two-Year Study on Yield and Yield Components of Maize-White Bean Intercropping Systems under Different Sowing Techniques

Food security is directly coupled with enhanced production under optimized cropping intensity. Intercropping is a diversified and sustainable agricultural technique with optimized cropping intensity. Intercropping is used to obtain a higher yield and more balanced products per unit area. This study was performed at Aidyn Research Institute, Nur Sultan, Kazakhstan, in 2018 and 2019 to identify the effects of different sowing patterns on maize-white bean (Zea mays–Phaseolus vulgaris) sowing systems. The field experiment was arranged in a randomized complete block design with three replications. Göynük-98 was used for white beans, and SY Miami was used for maize, with 20 cm and 40 cm row spaces for maize, and 10 cm and 20 cm row spaces for white bean and sole maize, sole white bean, maize-white bean-maize-white bean, maize-white bean-white bean-maize and white bean-maize-maize-white bean sowing systems. The results showed that wide row spacing was better than narrow row spacing in terms of land equivalent ratio (LER) for both maize and white beans, but grain yield was higher in narrow row spacing. Yield items for both maize and white beans showed higher values in intercropping. Grain yield was higher in sole sowing. The maize-white bean-white bean-maize sowing system for maize and the white bean-maize-maize-white bean sowing system for white beans were determined as the best sowing systems according to the yield components.

Row spacing and growth habit in peanut crops: Effects on seed yield determination across environments

Narrowing row spacing was expected to improve peanut crop performance, but the responses varied depending upon the evaluated environment and the growth habit of the plant. To clarify apparent inconsistencies, two cultivars with contrasting growth habits were sown at 52 cm and 70 cm row spacings in field experiments carried out in four environments. Vegetative and reproductive traits were evaluated. The leaf area index was always higher in the 52 cm than in the 70 cm row spacing, independently of the growth habit. Similarly, the light attenuation coefficient ( k ) was higher under narrow than under wide rows, but the cultivar with procumbent growth habit had a larger k and increased slightly the intercepted radiation respect to the erect type. These responses of the procumbent cultivar were driven by its lateral arrangements towards neighboring rows and its longer cycle duration. Narrow rows contributed to intercept approximately 14% more radiation than wide rows. These responses determined an improved biomass production through increases in the crop growth rate during the pod set period, with subsequent increases of the radiation use efficiency of this phase. Narrow row spacing enhanced seed and pod yields independently of the growth habit, but the relative importance of each seed yield component varied between cultivars. Seed numbers were more relevant for the erect growth habit, concurrently with the marked increase in total flower numbers of this cultivar. Seed weight was more relevant for the procumbent growth habit. On one hand, the erect growth habit caused a larger relative variation in seed and pod yields across environments than the procumbent one, particularly at narrow row spacing. On the other hand, the erect growth habit showed the lowest yield under wide rows. The small differences in biomass production between growth habits but the large difference in harvest index (procumbent > erect) contributed to an enhanced and more stable seed yield of the procumbent type, particularly when grown under narrow rows and linked to the large seed size of the runner cultivar. Results suggest that farmers should consider reducing row spacing as a way to increase peanut yield in the region under analysis.

Conventional and transgenic herbicide‐resistant soybean cultivars yielded similarly across five site‐years in Nebraska

AbstractSoybean [Glycine max (L.) Moench.] yield is determined by interactions amongst soybean cultivars’ genetic potential, agronomic practices, and environmental conditions. Despite the high adoption of herbicide‐resistant soybean cultivars across Nebraska and the United States, the comparative yield potential of non‐herbicide‐resistant (“conventional”) cultivars in not well understood. A field experiment was conducted at five locations across Nebraska in 2017 and 2018 to determine the effect of row spacing (15 and 30 in), cultivar maturity group (2.2–2.4 and 3.2), and herbicide resistance traits (conventional, glyphosate‐resistant, and glyphosate‐ and dicamba‐resistant) on soybean yield. Narrow row spacing increased the soybean yield in three of five research locations. The soybean yield in Auburn in 2017, Albion in 2018, and Cedar Bluffs in 2018 increased by 11.9, 10.2, and 11.4% in narrow compared with wide rows, respectively. Cultivar maturity group and herbicide resistance traits did not affect soybean yield under weed‐free experimental conditions. These results suggest that growers could benefit from earlier maturity groups, as they provide an opportunity for earlier harvest, allowing growers to better spread their field activities in the fall. The grain yield potential was similar between conventional and transgenic herbicide‐resistant cultivars. Therefore, conventional soybean cultivars can be a viable option when adequate weed management can be achieved through conventional weed management strategies.

Effect of Row Spacing and Plant Density on the Yield of Faba bean L. Under Very Differentiated Humidity Conditions

The research covered Polish low-tannin Faba bean &amp;lsquo;Albus&amp;rsquo;, and its yielding depending on the row spacing and plant density under very different humidity conditions across the research years. The mean multi-year faba bean seed yield was 4.01 t ha-1 and it was most correlated with the total rainfall in August and in June-August. Due to a considerable variation in the total rainfall and air temperature, the faba bean seed yield ranged from 0.69-2.14 t ha-1 in dry years (2018-2019) with high air temperature, from 6.64 to 6.59 ha-1 in humid years (2016-2017) with a considerably higher total rainfall and lower air temperature in June-August. There was no significant effect of the row spacing and plant density on the faba bean yielding, except for a significantly lower seed yield in 2019 following the application of the lowest plant density. Out of all the yield structure components, only the number of pods per plant for 60-75 plants per m2 was significantly lower than for 45 plants. The other yield structure components did not differ significantly due to the factors studied either, except for the LAI, the value of which for a narrow row spacing was significantly higher. There was found a significant correlation between all the plant traits and with the faba bean yield.

Measurement and modeling of diffuse irradiance masking on tilted planes for solar engineering applications

Photovoltaic and solar thermal projects require accurate solar irradiance data and models for the design, assessment, and forecasting of power output. For panels and solar collectors installed in arrays, the view toward the sky and ground is restricted by the surrounding rows. This paper analyzes the impact of view obstructions on the diffuse irradiance distribution in fixed-tilt arrays, addressing the insufficient research coverage to date. Irradiance was measured using high-precision pyranometers placed at ten positions throughout an experimental solar collector array for 3.5 and 6 m row spacings and 30°, 37.5°, and 45° tilt angles (relative row spacings between 0.68 and 1.51). A novel anisotropic transposition model was developed to calculate the diffuse tilted irradiance along the collector height, accounting for diffuse irradiance masking due to view obstructions. The model was also solved inversely, obtaining local global horizontal irradiance from global tilted irradiance. The validation showed that the model accurately captures the distinct shape of the diffuse irradiance distribution. Results indicate a strong effect of view obstructions for narrow row spacings and steep tilt angles. For the most extreme configuration (3.5 m row spacing, 45° tilt angle, 1.67 relative row spacing), the diffuse irradiance was reduced to 64% at the bottom and 89% on average, relative to the top of the collector. As a consequence, measurements at the top can result in biased performance assessments.