Row Spacing Research Articles

Effect of Different Weed Management Practices on Growth Characters of Chickpea in Mid-hills of Himachal Pradesh, India

Chickpea (Cicer arietinum) is one of the most important pulse legumes in many parts of the world. India is largest producer of chickpea in the world, sharing 65 and 70 % of the total global area and production, respectively. Different weed control practices use of herbicides were followed for better management. Application of herbicide at critical growth stages followed by one or two hand weeding at proper time or manipulation of row spacing for improving the weed suppressing effect of crops gives marginal improvement in crop yield. A field experiment titled “Effects of Different Weed Management Practices on Growth Characters of Chickpea in Mid-hills of Himachal Pradesh” was conducted during rabi season of 2022 at Chamelti Agriculture Farm, MS Swaminathan School of Agriculture, Shoolini University of Biotechnology and Management Sciences, Solan. The soil of the experimental field was sandy loam in texture, slightly alkaline in reaction with EC in a safer range, medium in organic carbon, available nitrogen, potassium, and high in available phosphorus. The experiment was laid out in randomized block design with three replications comprising ten weed management treatments viz. (T1) One hand weeding at 20 DAS, (T2) Two hand weeding at 20 and 40 DAS, (T3) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE), (T4) Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS, (T5) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + One hand weeding at 30 DAS, (T6) Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS + One hand weeding at 40 DAS, (T7) Fenoxaprop-p-ethyl 9.3 EC @ 60 g ha-1 (PoE) at 25 DAS + One hand weeding at 40 DAS, (T8) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS, (T9) Weed free and (T10) Weedy Check. The recommended dose of fertilizer (30:60:30 kg ha-1) was applied through Urea, SSP, and MOP at the time of sowing. PBG-7 variety of chickpea was used for sowing. Weed management practices were done as per treatment. Other crop management practices were followed as per the recommendation of the area. Application of (T8) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS registered higher growth parameters viz. plant height, number of branches plant-1, dry matter accumulation and crop growth rate. Thus, study suggest that chickpea can successfully grown under Mid-hills of Himachal Pradesh on (T8) Pendimethalin 30 EC @ 1.0 kg ha-1 (PE) + Imazethapyr 10 SL @ 1.0 kg ha-1 (PoE) at 25 DAS.

Multi-CC: A New Baseline for Faster and Better Deep Clustering

The aim of our paper is to introduce a new deep clustering model called Multi-head Cross-Attention Contrastive Clustering (Multi-CC), which seeks to enhance the performance of the existing deep clustering model CC. Our approach involves first augmenting the data to form image pairs and then using the same backbone to extract the feature representation of these image pairs. We then undertake contrastive learning, separately in the row space and column space of the feature matrix, to jointly learn the instance and cluster representations. Our approach offers several key improvements over the existing model. Firstly, we use a mixed strategy of strong and weak augmentation to construct image pairs. Secondly, we get rid of the pooling layer of the backbone to prevent loss of information. Finally, we introduce a multi-head cross-attention module to improve the model’s performance. These improvements have allowed us to reduce the model training time by 80%. As a baseline, Multi-CC achieves the best results on CIFAR-10, ImageNet-10, and ImageNet-dogs. It is easily replaceable with CC, making models based on CC achieve better performance.

Horizontal variability and diurnal fluctuation of soil respiration in corn and soybean rows

This study evaluated the horizontal variability and diurnal fluctuation of soil respiration to accurately capture changes in carbon flux during agricultural production in Lishu County, Jilin Province, China. Corn (Zea mays L.) and soybean (Glycine max L.) were planted with 60-cm row spacing in 2020. The soil respiration rate (SRR) was measured at 2-hour intervals on July 1, August 1, and September 25 using a portable, closed chamber at five positions, P0, P15, P30, P45, and P60, denoting specific distances from the crop rows. The SRR between crop rows was affected both by dates and fields with the coefficient of variation ranging between 7.1 and 37.7%. The SRR at P45 was closest to the mean SRR, with a relative deviation of 0.09–4.85% on July 01 and August 01 in corn and soybean fields. On September 25, the optimal position to measure SRR was between P45 and P60. The sampling dates influenced the optimal time for measuring SRR but were mostly concentrated between 9:00 and 11:00 (24-hour clock) for corn and between 11:00 and 13:00 for soybean. The root biomass of crop rows and diurnal soil temperature were the main factors affecting horizontal variability and diurnal fluctuation of SRR, respectively. We recommend an SRR sampling strategy at P45 between 9:00 and 11:00 for corn and between 11:00 and 13:00 for soybean to decrease the effects of horizontal variability and diurnal fluctuation of SRR.

Study on the Shear Resistance Performance of Grouped Stud Connectors.

In order to further investigate the grouped stud effect on the force properties of stud connectors, based on the premise that the correctness of the finite element simulation method, in this paper, a finite element model of grouped stud connectors was developed, and the grouped stud effect and its sensitivity factors were analyzed in order to validate the recommended formula for calculating the shear capacity of grouped stud connectors. Results show that the number of grouped stud rows and stud row spacing have a significant influence on the grouped stud effect, and the unevenness coefficient of grouped stud force is negatively correlated with the number of grouped stud rows as well as the grouped stud row spacing. Grouped stud connectors with commonly used concrete grades greater than C50 and height-to-diameter ratios of greater than 4 in steel-concrete composite structural bridges are insensitive to changes in the concrete strength grades and the length of the studs. The direction of force transmission for grouped stud changes with the change in loading angle and the unevenness coefficient of force for the grouped stud will therefore be reduced. By comparing the results of the 62 existing groups of grouped stud connectors push-out tests, the mean of the tested to calculated value ratio was found to be 1.12, the variance was 0.023, the dispersion was small, and it was shown that the recommended formula has a high degree of accuracy. The results of this paper can be used as a theoretical basis for the study of the shear stress performance of grouped stud connectors.

Evaluating the impacts of wide row upland cotton (Gossypium hirsutum L.) production in Georgia

AbstractSuccess stories of wide row cotton production have generated producer interest across the cotton belt. The objective of this study was to quantify the effect of row spacing on (1) cotton growth and development and (2) lint yield and fiber quality in Georgia. The cotton cultivar Deltapine DP 1646 (Bollgard 2, XtendFlex; Bayer Crop Science) was planted in 2021 and 2022 in Tifton, GA, at row spacings of 91 cm, 122 cm, 152 cm, and 183 cm. Although canopy closure was delayed in wider row spacings compared to the 91‐cm spacing, all other crop growth and development trends did not differ among row spacings. Similarly, row spacing had no effect on the incidence of boll rot/hard lock. The 91‐cm row spacing yielded 1734 kg lint ha−1. The 183‐cm row spacing reduced yield by 15% compared with the grower's standard row spacing of 91 cm. Fiber quality parameters did not differ among row spacing treatments. Seed costs can be reduced in all wide row systems evaluated for cotton, and the 122 and 152‐cm row spacings had similar yields to the 91‐cm row spacing. However, Georgia growers produce peanuts (Arachis hypogea L.) and corn (Zea mays L.), the most common rotational crops for cotton producers, using a 91‐cm row spacing. Consequently, the simplest transition to wide row production would be the 183‐cm spacing, which incurred yield penalties in the current study. Thus, a 91‐cm row spacing is still the most feasible option for Georgia cotton producers.

The Effect of Plant and Row Configuration on the Growth and Yield of Multiple Cropping of Soybeans in Southern Xinjiang, China

To study the optimal plant row configuration of the multiple cropping of soybeans that are suitable for planting in southern Xinjiang, a field experiment using soybean variety SN35 was carried out employing different plant row designs. Three row spacing treatments of 15 cm (H1), 30 cm (H2), and 45 cm (H3) and three density treatments of 52.56 million (M1), 55 million (M2), and 60 million (M3) plants per hectare were set up in this experiment to explore the effects of different plant row spacing configurations on agronomic traits, photosynthetic characteristics, dry matter accumulation, and the soybean yield of the multiple cropping of soybeans. The results showed that the soybeans’ plant height, diameter, main stem node number, leaf shape index, leaf area index (LAI), leaf area duration (LAD), and pod dry matter distribution ratio increased gradually with the growth process. In contrast, the stem dry matter distribution ratio decreased gradually, and the leaf dry matter distribution ratio first increased and then decreased. The plant height of the soybeans treated with H2M3 was the highest, reaching 67.38 cm. The number of primary stem nodes of the soybeans treated with H1M3 was the highest, reaching 12.7 nodes. The stem diameter of the soybeans treated with H1M1 was the highest, reaching 0.64 cm. The leaf shape index of the soybeans treated with H3M1 was the highest, reaching 2.72. Intercellular CO2 concentration closely affects the final yield; the correlation coefficients with the pod number per plant, seed number per plant, and yield reached 0.75, 0.78, and 0.87, respectively. The theoretical maximum hundred-grain weights under the H1M1 and H2M1 treatments were higher, reaching 20.33 g and 17.98 g, respectively. The H3M3 treatment had the most significant one-hundred-grain weight, reaching 21.27 g. The soybean yield of each density treatment was M3 > M1 > M2. With the increase in row spacing, the average pod number per plant, grain number per plant, grain weight per plant, and yield of soybeans decreased gradually, and the hundred-grain weight increased gradually. The yield of the density treatment with 60 million plants per hectare under 15 cm row spacing was the highest, reaching 6155.8 kg·hm−2, followed by the density treatment with 60 million plants per hectare under 30 cm row spacing, reaching 5850.6 kg·hm−2.

Slurry pressure at the cutting zone in multi-wire sawing: An experimental study

Multi-wire sawing has been widely used in the processing of semiconductor material wafers employed in integrated circuits, solar cells, etc. Recently, free abrasive multi-wire sawing has been gradually replaced by solid abrasive multi-wire sawing technology in the domain of solar wafers. However, free abrasive sawing still plays an important role in the processing of electronic-grade monocrystalline silicon wafers, where the requirements on the wafer quality are continuously increasing. Because the free abrasive multi-wire sawing process is very complex, its material removal mechanisms are not fully understood. In this study, experiments were designed to measure the slurry pressure at the cutting zone during a free abrasive multi-wire sawing process to fabricate monocrystalline silicon wafers, and the pressure distribution condition throughout the cutting zone was obtained. Two sets of micropores of 0.17 mm diameter were processed on the experimental workpiece to transmit the cutting zone fluid pressure to the sensor. Each group of micropores consisted of 17 small pores, divided into three rows, with the row spacing consistent with the pitch width of the wire guide. During installation, the center line of each row of micropores was aligned with the center line of the steel wire. The pressure at the cutting zone was measured using the micropores to transfer the slurry pressure to the sensor. Calibration experiments were conducted by considering the capillary effects of the micropores, and the actual pressure at the cutting zone was obtained. Experimental results show that the slurry pressure was 0.16 bar at 40 mm near the slurry inlet. As the distance from the slurry inlet increased, the pressure fluctuated around 0.14 bar. Furthermore, at a distance of 160 mm from the slurry inlet, the sensor was not able to detect the pressure at the cutting zone. The experimental results from the free abrasive multi-wire sawing pressure measurement showed that material removal involves a three-body action comprising the metal wire, abrasive grains, and workpiece. At the cutting zone far from the location of the slurry inlet, forming a stable and continuous film with the slurry is difficult. The experimental results confirm that the force of material removal during the sawing process mainly comes from the wire tension of the steel wire. The film thickness of the slurry in the cutting zone is determined by the diameter of the abrasive between the wire and ingot. The experimental conclusion is of great significance for understanding the complex material removal process in the cutting zone for multi-wire sawing.

Effect of Row Spacing and Nitrogen Sources on Growth, Yield and Economics of Babycorn (Zea mays L.)

Effect of Row Spacing and Nitrogen Sources on Growth, Yield and Economics of Babycorn (Zea mays L.)

Real-Time 3D Liver Tumor Localization via Combined Optical Surface Imaging and an X-Ray Projection from Arbitrary Imaging Angles

A deep learning (DL)-based, deformable registration-driven liver tumor localization technique was developed for onboard deformable motion tracking. The technique (Surf-X360-Bio) uses in-room optical surface imaging and an x-ray projection at an arbitrary scan angle to solve volumetric liver and liver tumor motion in real-time. Surf-X360-Bio solves the volumetric motion of the liver and localizes the liver tumor, through deforming liver and liver tumor meshes segmented on prior 4D-CTs/CBCTs. It uses real-time onboard information from an optical surface image and a simultaneously-acquired x-ray projection (from an arbitrary scan angle). Surf-X360-Bio localizes tumors via two steps: liver boundary motion estimation and intra-liver motion derivation. Surf-X360-Bio first estimates liver boundary motion by a patient-specific surface imaging model (Surf), utilizing the correlation between the external body surface motion and the internal liver boundary motion. As the correlation can be imperfect, the residual motion estimation errors were corrected by a patient-specific, angle-agnostic x-ray imaging model (X360). X360 deformed the liver boundary to match motion-related imaging features encoded in an arbitrarily-angled x-ray projection, using the Surf output for initialization. X360 adopted a geometry-aware learning module to extract and adapt to angle-varying features of arbitrarily-angled x-ray images, by calculating the projection system matrix of each x-ray image on-the-fly during model training and inference. After the liver boundary motion estimation by Surf and X360, intra-liver deformation was solved by a biomechanical model (Bio) to propagate the liver boundary motion inside to localize the tumors. The DL-based Bio model used domain knowledge of tissue biomechanics and finite element analysis (FEA) to solve intra-liver motion, with a much faster speed than conventional FEA methods to meet the real-time constraint. Surf-X360-Bio was evaluated using a dataset of 34 liver patients. Liver tumor localization accuracy was evaluated by the Dice similarity coefficient (DSC), the 95-percentile Hausdorff distance (HD95), and the center-of-mass error (COME). Using 3,306 motion scenarios spanning the 360 degree x-ray scan angles for each testing patient, Surf-X360-Bio localized the liver tumors to 0.81 (mean) ± 0.16 (s.d.) in DSC, 2.5 ± 1.7 mm in HD95, and 2.1 ± 1.8 mm in COME. In comparison, the prior reference image without deformable registration-driven localization yielded 0.42 ± 0.29 in DSC, 8.1 ± 5.2 mm in HD95, and 8.5 ± 5.2 mm in COME. Via Surf-X360-Bio, the overall inference time was below 230 ms for each case. Combining optical surface imaging and x-ray imaging, Surf-X360-Bio achieved fast (<250 ms inference time), accurate (mean error < 2.1 mm), and robust liver tumor localizations at arbitrary x-ray scan angles for real-time, marker-less 3D deformable motion tracking.

Evaluation of insertion quality of a slim perimodiolar electrode array

ObjectivesThe influence of cochlear morphology and electrode array design on scalar position and dislocation rates is of great interest in CI surgery. The aim of this study is to evaluate scalar position and specific points of dislocation in relation to cochlear morphology in patients implanted with a new slim perimodiolar electrode array.Materials and methodsPatients were implanted using the slim modiolar electrode array (= SMA) (= 532/632 electrode array of Cochlear™). Postoperative imaging was performed via cone beam computed tomography (CBCT) and the scans were analyzed regarding cochlear morphology (distances A and B and cochlear height), scalar location of the electrode array, basal insertion depth and apical insertion angle. Furthermore, electrode array design and surgical protocols were evaluated.Results81 ears implanted with the SMA were retrospectively included. We evaluated 3 electrode array tip fold over intraoperatively via X-ray imaging and performed revision during the same surgery. The CBCT scans showed 76 initial scala tympani (ST) insertions without dislocation. Two ears showed a dislocated array, one at 77° and the other at 163°. Three arrays were inserted into scala vestibuli (SV) via cochleostomy. These patients showed no signs of obliteration. Cochlear morphology showed no influence on angular insertion depth and scalar position.ConclusionsThe SMA showed a very low rate of scalar dislocations due to its slim electrode array design (2.7%). We could find a learning curve regarding the handling and the risk of dislocation and tip fold over with this electrode array. The rate of intraoperative tip fold over detection via X-ray imaging was 3.7%. Therefore, we highly recommend X-ray imaging and transimpedance matrix measurements within the surgery protocol. Scala vestibuli insertions happened in patients with cochleostomy only. We could identify two specific points of dislocation depending on electrode array design.

Optimalisasi Pengaturan Jarak Tanam dan Pemberian Pupuk P Terhadap Produksi Tanaman Jagung Pulut (Zea mays ceratina kulesh)

Pulut corn is a type of corn that has a fluffier taste and has the advantage of being able to keep blood sugar levels stable. The need for corn commodity continues to increase along with the increase in population. The purpose of this study was to determine the effect of spacing and application of P fertilizer on growth and production of corn pulut. This research was conducted in September 2022-November 2022 in Antirogo Village, Sumbersari District, Jember Regency. The research design used was a factorial randomized block design (RBD). The first factor is the spacing consisting of conventional spacing of 70cm x 20 cm and row spacing of 2:1 legowo with a spacing of 40cm x 20 cm x 100 cm. The second factor is the application of P fertilizer with 5 levels, respectively 100kg/ha, 125kg/ha, 150kg/ha, 175kg/ha, and 200kg/ha. There was an interaction between the treatment of jajar legowo spacing and 200 kg/ha P fertilizer on stem diameter. Treatment Jajar legowo spacing has a significantly different effect on the observation of cob diameter and light intercept. Meanwhile, the P fertilizer treatment had a significantly different effect on cob weight. Based on these results, it can be concluded that the use of a spacing of 70 x 20 cm can increase cob diameter and P fertilization at a dose of 100 kg/ha can increase cob weight.

Pigeonpea (Cajanus cajan L.) growth and yield with varying spacing and fertilizer

A field experiment was conducted during kharif season of 2020 at the research farm of Amar Singh College Lakhaoti. Treatment consistedof 3 Row spacing (30, 60 and 90 cm) and 3 levels of DAP application (control, 100 and 200 kg/ha). Results showed that treatment of30 cm row spacing produced at par plant height compared to 60 cm row spacing. Treatment of 100 kg DAP per hectare producedsignificantly plant height as compared to 200 kg DAP per hectare. The same trend was observed for a number of branches, leavesand dry matter accumulation. Treatment of 60 cm row spacing was found to be significantly superior over 30 cm raw spacing for yieldand yield attributes treatment of 30 cm raw spacing recorded significantly higher protein content as compared to 60 cm raw spacing,whereas treatment of 100 kg DAP per hectare was found significantly superior over control and 200 kg DAP per hectare for variousgrowth parameters, yield attributes and yield.

Nitrogen balance and gap of a high yield tropical soybean crop under irrigation.

Nitrogen (N) is the most extracted and exported element by the soybean crop. In high yield tropical environments with irrigation, little is known about N accumulation in different soybean plant organs as well as the N balance. The objective of this study was to characterize soybean growth, N accumulation in plant organs, N balance, and N gap in a high yield tropical environment. This study was performed in a homogeneous field, in a soil with low organic matter, with 20kg ha-1 of N, under furrow fertilization. Evaluations were performed ten times, temporally distributed from emergence to senescence. The soybean cultivar used was 'RK7518 IPRO' and was sown with row spacing of 0.45m and a seeding rate of 300,000 plants ha-1. Plant N partition, N from the biological N fixation (BNF), grain yield, crop harvest index (HI), N harvest index (NHI) with and without root contribution were evaluated. Also, at the grain filling stage the N gap was evaluated from the soil by difference between whole plant accumulated N and the amount of N from BNF. The average grain yield was 6,470 kg ha-1 and leads to a negative partial balance of N of -33.4 and -42.8 kg[N] ha-1 with and without roots, respectively. The N gap from the soil was 231.7 kg[N] ha-1. It is recommended to adopt techniques that increase the efficiency of BNF and the soil N accumulation to balance these production systems in the medium to long term.

Optimising the wave attenuation of bamboo fences using the numerical wave model SWASH

Mangroves protect tropical coastlines from flooding and erosion, reducing flood risks along coastal communities worldwide. Nevertheless, mangrove forests have experienced considerable losses due to activities like urbanization and aquaculture, exposing coastal areas to wave attack. To restore mangroves at eroding coastlines, structures formed by bamboo poles and a brushwood filling are used to shelter the coast from waves, and create a favourable habitat for mangrove colonization. However, these structures often lose their brushwood filling during storms, resulting in high maintenance costs. This study proposes a new type of design to reduce maintenance expenses, consisting of only vertical bamboo poles without a filling of brushwood. Structure designs are evaluated for a case study in Demak, Indonesia, using the numerical wave model SWASH to predict wave attenuation through the structures. Field measurements and WaveWatch III data are analyzed to obtain the design conditions for the structures in Demak. SWASH is validated against laboratory experiments, and applied to investigate the optimum number of rows and their optimum spacing (in the direction of wave propagation). The model shows that for a structure consisting of two rows of bamboo poles, the transmission rate Et/Ei decreases from 75% to 55% when the row spacing in the wave direction is increased from sx = 0.42 m to sx = 5.8 m. Larger spacings do not result in less transmission, and at least three rows are needed to have a transmission rate lower than 50 % - a common wave reduction target used in restoration efforts with structures. This study thus identifies potential strategies to maximize wave attenuation by bamboo structures, which can be used to reduce wave attack along muddy coasts without the need of a brushwood filling. Hereby, it provides an economically and user friendly alternative with respect to the previous brushwood structure designs, as it requires less material costs and maintenance. In addition, this study presents a new method to schematize these kind of structures in SWASH in an efficient way.

Effects of Seed Rate and Row Spacing on Growth, Yield Components and Yield of Coriander at Highland and Mid-Altitudes of Bale, South-Eastern Ethiopia

Effects of Seed Rate and Row Spacing on Growth, Yield Components and Yield of Coriander at Highland and Mid-Altitudes of Bale, South-Eastern Ethiopia

Construction and application of a new watermelon germplasm with the phenotype of dwarf and branchless.

Watermelon (Citrullus lanatus) is a widely cultivated cucurbitaceae crop appreciated by consumers worldwide. However, the long vine and abundant lateral branches of currently cultivated watermelon varieties hinder light simplification and mechanized cultivation, affecting plant spacing and row spacing requirements. To address this, the development of watermelon with dwarf and branchless traits has become a crucial direction for the industry. In previous studies, the genes controlling dwarf (Cldw-1) and branchless (Clbl) traits were mapped and cloned. Marker-assisted selection markers, dCAPS3 and dCAPS10, were developed for these traits, respectively. In this study, the dwarf germplasm WM102 and the branchless germplasm WCZ were crossed to obtain F1 .Further self-crossing of the F1 individuals resulted in the F2 population. Through multiple generations of self-pollination, a new watermelon germplasm DM with double mutation (dwarf and branchless) was obtained. DM exhibited stable inheritance without segregation. Moreover, DM was used as a donor parent for crossing with commercial watermelon materials, and near-isogenic lines (NILs) with the dwarf and branchless traits were developed. These NILs carry additional desirable agronomic traits and provide valuable genetic resources for future watermelon breeding programs, particularly in improving plant architecture and overall quality. The development and application of DM and NILs hold great potential for advancing the watermelon industry toward industrialization, large-scale cultivation, and enhanced plant architecture.

Optimizing agronomic practices for hard winter wheat production in the Great Plains with respect to seeding rate, row spacing, and variety

AbstractWinter wheat (Triticum aestivum L.) yield in dryland areas is optimized by the improvement of genetics in combination with ideal production practices. Different combinations of seeding rate and row spacing can influence the development of wheat plants, impacting wheat yield and its components. To determine the influence of these practices, yield components, water use efficiency (WUE), biomass, and subsequent grain yield were evaluated in an experiment conducted at the High Plains Agricultural Laboratory, Sidney, NE, from 2019 until 2022, using a split‐plot randomized complete block design with four replications. Treatments consisted of four different row spacings (19, 25, 31, and 51 cm), three seeding rates (1.05, 2.1, and 3.1 million seeds ha−1), and two high performing winter wheat varieties—‘Ruth’ and ‘Robidoux’. Row spacing showed differences in wheat yield (p &lt; 0.0001) across all years, with a significant effect of seeding rate only in 1 year and an interaction effect of the three factors in 2022 alone. Higher wheat yield was achieved with the two narrower row spacings (19 and 25 cm) compared to the wider row spacings of 38 and 51 cm. The treatment combining the 19 cm row spacing and either 2.1 or 3.1 million seed ha−1 seeding rate had the greatest yields in most years. Narrower row spacings had improved WUE in drier years as compared to wider row spacings.

Effect of Different Row Spacing and Sowing Density on Selected Photosynthesis Indices, Yield, and Quality of White Lupine Seeds

The use of appropriate plant spacing in the canopy is an important and cost-free agrotechnical factor for increasing seed yield. Proper row spacing and sowing density are important in maintaining adequate plant light, ensuring good physiological processes, and influencing the nutritional status of plants. As a consequence, this leads to better plant productivity while maintaining economic profitability. A four-year field experiment with white lupine was conducted in 2016–2019 at the Experimental Station for Cultivation Assessment in Przecław in southeastern Poland. The factors of the experiment were different row spacing (15 and 30 cm) and sowing density (60, 75, and 90 pcs m−2). Row spacing and sowing density had no significant effect on the yield obtained, the number of pods per plant, and the weight of 1000 seeds of white lupine. There was also no effect of experimental factors on nodulation and chlorophyll fluorescence parameters (Fv/Fm, Fv/F0, PI, and RC/R). The use of wider row spacing (30 cm) and the lowest sowing density (60 pcs m−2) resulted in the highest chlorophyll content. For the LAI index, the highest value was found at a row spacing of 15 cm. However, lower plant density per unit area had an effect on increasing the number of seeds per pod and seed weight per plant, which was associated with better conditions for plant growth. It was shown that greater competition between lupine plants in the canopy increased the height of the first pod set without affecting their height.

Research on airflow convergence patterns and air distribution characteristics under multi-column attachment ventilation

Multi-column attachment ventilation (M-CAV) is usually delivered to the occupied zone by floor-attached airflows in large spaces. However, after the floor-attached airflow converges, the original air distribution will change, which will have an important impact on the traditional air distribution design. In this paper, airflow convergence patterns and air distribution characteristics in the most common double-column and tri-column layouts are studied by experiments and computational fluid dynamics (CFD) simulations. A 1:3 scaled-down model was established for velocity experiments and flow field visualization, and the results were used to verify and optimize the CFD model. The results indicated a seagull-like convergence flow pattern under the symmetric double-column layout. Under the axisymmetric layout with different column spacings, the floor-attached airflow in the half-open air outlet mode exhibited full convergence with the merging point (point MP) and combined point (point CP), partial convergence with point MP, and non-convergence without point MP and point CP. Under the centrosymmetric layout, an M-shaped velocity distribution was formed, and no airflow converged. For equal-velocity conditions, the dimensionless convergence axial velocity distributions for different air supply velocities was approximately consistent. In the fully-open air outlet mode, the floor-attached airflow could be divided into the collision-dominated region, the combined collision and convergence-dominated region, and the convergence-dominated region based on the forms of airflow interaction. For unequal-velocity conditions, the high-velocity airflow restricted the diffusion of the low-velocity airflow.

Does narrow row spacing suppress weeds and increase yields in corn and soybean? A meta-analysis

AbstractNarrow row spacing (&lt;76 cm) could improve crop competitiveness, suppress weeds and might provide yield advantage. Many studies have been conducted to evaluate the impact of narrow row spacing; however, no quantitative synthesis of these studies exists. The objectives of this meta-analysis were to (1) quantify the overall effect of narrow row spacing (&lt;76 cm) on weed density, biomass, control, weed seed production, and yield in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] compared with 76-cm row spacing, and (2) assess the influence of agronomic management decisions (tillage type, weed management, herbicide application frequency and time) on effect of narrow row spacing on weed suppression and corn and soybean yield. We compiled 1,904 pair-wise observations from 35 studies conducted in 12 states in the United States during 1961 to 2018. Averaged across individual observations, narrow row spacing suppressed weed density by 34%, weed biomass by 55%, and weed seed production by 45%, while it improved weed control by 32% and crop yield by 11% compared with 76-cm row spacing. Narrow row spacing in soybean suppressed weed density by 42%, weed biomass by 71%, and increased crop yield by 12% compared with 76-cm row spacing. Although narrow row spacing had a nonsignificant effect on response variables in corn, the number of studies (n = 1 to 6) and observations (n = 1 to 59) addressing each response variable were limited. Tillage type (conventional and reduced) did not influence the response of weed density, control, and seed production in narrow row spacing; however, weed biomass and weed seed production were more greatly reduced with the sequential application of herbicides compared with a single application. Thus, narrow row spacing in soybean can be integrated with other options for management of herbicide-resistant weeds.