Narrow Row Spacing Research Articles

Optimizing daylily (Hemerocallis citrina Baroni) cultivation: integrating physiological modeling and planting patterns for enhanced yield and resource efficiency

IntroductionOptimizing the dynamics of daylily (Hemerocallis citrina Baroni) growth under various planting patterns is critical for enhancing production efficiency. This study presents a comprehensive model to simulate daylily growth and optimize planting patterns to maximize bud yield while minimizing land resource utilization.MethodsThe model incorporates source-sink relationship specific to daylilies into physiological process modeling, considering environmental factors such as micro-light and temperature climate, and CO2 concentration. Spatial factors, including planting pattern, row spacing, plant spacing, and plant density were examined for their impact on light interception, photosynthesis, and resource efficiency. Employing partial least square path modeling (PLS-PM), we analyzed the interrelations and causal relationships between planting configurations and physiological traits of daylily canopy leaves and buds. Through in situ simulations of 36 planting scenarios, we identified an optimal configuration (Scenario ID5) with a density of 83,000 plants·ha−1, row spacing of 0.8 m, and equidistant planting with a plant spacing of 0.15 m.Results and discussionOur research findings indicate that increased Wide+Narrow row spacing can enhance yield to a certain extent. Although planting patterns influence daylily yield, their overall impact is relatively minor, and there is no clear pattern regarding the impact of plant spacing on individual plant yield. This modeling approach provides valuable insights into daylily plant growth dynamics and planting patterns optimization, offering practical guidance for both farmers and policymakers to enhance daylily productivity while minimizing land use.

Soybean seed yield, protein, and oil concentration for a modern and old genotype under varying row spacings

Progress in soybean (Glycine max L.) breeding has led to a reduction in optimal seeding rates due to enhanced branching capacity over time. However, less is known about the changes in canopy architecture between old and modern soybean genotypes at varying row spacing and their impact on yield and seed quality through the main stem and branches. Therefore, this study aimed to i) evaluate yield and seed quality responses of an old and modern soybean genotype at different row spacings and ii) examine the yield and seed quality of branches and the main stem. Trials were conducted in Kansas (United States, US) during 2020 and 2021, comparing two genotypes (old, released in 1980, and modern, released in 2013) at four row spacings (0.19, 0.38, 0.76, and 1.52 m) under rainfed conditions. Seed yield and quality (protein and oil concentrations, %) were assessed at the end of each growing season. In 2021, both genotypes had low and similar yields at all row spacings (averaging 2481 kg ha−1) with 2.5 % less protein on branches compared to the main stem. However, 2022 resulted in a high-yielding environment, with the modern yielding 50 % more (3584 kg ha−1) than the old (2315 kg ha−1) genotype in narrow row spacings (<0.38 m). Additionally, the modern genotype showed a three-fold greater contribution to yield from branches (1113 kg ha−1) relative to the old genotype (379 kg ha−1). Despite the high yields observed in narrow rows, the modern genotype maintained protein levels. These results highlight the importance of row spacing as a key management practice for improving yield while maintaining protein levels in high yield conditions.

Narrow row maize cultivation increased grain and forage yield of hybrids in Ohio and Pennsylvania

AbstractAlthough there has been a resurgence in interest among farmers in producing narrow row hybrid maize (Zea mays L.) in the Eastern UnitedStates, agronomic recommendations for modern hybrids are limited. To address this issue, field trials were carried out from 2016 to 2018 in Ohio and Pennsylvania (10 unique site‐year combinations), aiming to answer the following questions: (i) Do modern hybrids differ in their response to narrow (38 cm) and conventional (76 cm) row spacing? (ii) Is there a yield increase for narrow row production? The study was planted in a split‐plot randomized complete block design with four replications. The whole plot factor was row spacing, and the subplot factor was hybrid. Two hybrids (P0506AM and P0604AM) were in an “early”‐season group, and two hybrids (P1197AM and P1443AM) were “full”‐season hybrids. Both P0506AM and P1443AM were identified as AQUAmax hybrids and had superior seed company drought tolerance ratings over their maturity pairing counterpart. Grain and forage yield were 4% and 8% greater, respectively, for the narrow row spacing across hybrids. Hybrid differences in drought tolerance designation did not result in grain or forage yield differences under varied row spacings. There was no hybrid × row spacing interaction. In most site‐years, P1197AM hybrid produced the greatest grain and forage yields, though P1443AM and P0506AM were similar in most cases. Results suggest a minor advantage in yield (≤8%) from narrow rows in Ohio and Pennsylvania, though other considerations that include cost to conversion should be considered prior to adoption.

Narrowing row spacing and adding inter-block promote the grain filling and flag leaf photosynthetic rate of wheat under enlarged drip tube spacing system.

Enlarging the lateral space of drip tubes saves irrigation equipment costs (drip tubes and bypass), but it will lead to an increased risk of grain yield heterogeneity between wheat rows. Adjusting wheat row spacing is an effective cultivation measure to regulate a row's yield heterogeneity. During a 2-year field experiment, we investigated the variations in yield traits and photosynthetic physiology by utilizing two different water- and fertilizer-demanding spring wheat cultivars (NS22 and NS44) under four kinds of drip irrigation patterns with different drip tube lateral spacing and wheat row spacing [① TR4, drip tube spacing (DTS) was 60cm, wheat row horizontal spacing (WRHS) was 15cm; ② TR6, DTS was 90cm, WRHS was 15cm; ③ TR6L, DTS was 90cm, WRHS was 10cm, inter-block spacing (IBS) was 35cm; and ④ TR6S, DTS was 80cm, WRHS was 10cm, IBS was 25cm]. The results showed that under 15-cm equal row spacing condition, after the number of wheat rows served by a single tube increased from four (TR4, control) to six (TR6), NS22 and NS44 exhibited a marked decline in yield. The decline of NS22 (9.93%) was higher than that of NS44 (9.04%), and both cultivars also showed a greater decrease in grain weight and average grain-filling rate (AGFR) of inferior grains (NS22: 23.19%, 13.97%; NS44: 7.78%, 5.86%) than the superior grains (NS22: 10.60%, 8.33%; NS44: 4.89%, 4.62%). After the TR6 was processed to narrow WRHS (from 15 to 10cm) and add IBS (TR6L: 35cm; TR6S: 25cm), the grain weight per panicle (GWP) and AGFR of superior and inferior grains in the third wheat row (RW3) of NS22 and NS44 under TR6L increased significantly by 26.05%, 8.22%, 14.05%, 10.50%, 5.09%, and 5.01%, respectively, and under TR6S, they significantly increased by 20.78%, 9.91%, 16.19%, 9.28%, 5.01%, and 4.14%, respectively. The increase in GWP and AGFR was related to the increase in flag leaf area, net photosynthetic rate, chlorophyll content, relative water content, actual photochemical efficiency of PSII, and photochemical quenching coefficient. Among TR4, TR6, TR6L, and TR6S, for both NS22 and NS44, the yield of TR6S was significantly higher than that of TR6 and TR6L. Furthermore, TR6S showed the highest economic benefit.

System of wheat intensification (SWI): Effects on lodging resistance, photosynthetic efficiency, soil biomes, and water productivity.

Intense cultivation with narrow row spacing in wheat, a common practice in the Indo-Gangetic plains of South Asia, renders the crop more susceptible to lodging during physiological maturity. This susceptibility, compounded by the use of traditional crop cultivars, has led to a substantial decline in overall crop productivity. In response to these challenges, a two-year field study on the system of wheat intensification (SWI) was conducted. The study involved three different cultivation methods in horizontal plots and four wheat genotypes in vertical plots, organized in a strip plot design. Our results exhibited that adoption of SWI at 20 cm × 20 cm resulted in significantly higher intercellular CO2 concentration (5.9-6.3%), transpiration rate (13.2-15.8%), stomatal conductance (55-59%), net photosynthetic rate (126-160%), and photosynthetically active radiation (PAR) interception (1.6-25.2%) over the existing conventional method (plant geometry 22.5 cm × continuous plant to plant spacing) of wheat cultivation. The lodging resistance capacity of both the lower and upper 3rd nodes was significantly higher in the SWI compared to other cultivation methods. Among different genotypes, HD 2967 demonstrated the highest recorded value for lodging resistance capacity, followed by HD 2851, HD 3086, and HD 2894. In addition, adoption of the SWI at 20 cm × 20 cm enhanced crop grain yield by 36.9-41.6%, and biological yield by 27.5-29.8%. Significantly higher soil dehydrogenase activity (12.06 μg TPF g-1 soil hr-1), arylsulfatase activity (82.8 μg p-nitro phenol g-1 soil hr-1), alkaline phosphatase activity (3.11 n moles ethylene g-1 soil hr-1), total polysaccharides, soil microbial biomass carbon, and soil chlorophyll content were also noted under SWI over conventional method of the production. Further, increased root volumes, surface root density and higher NPK uptake were recorded under SWI at 20×20 cm in comparison to rest of the treatments. Among the tested wheat genotypes, HD-2967 and HD-3086 had demonstrated notable increases in grain and biological yields, as well as improvements in the photosynthetically active radiation (PAR) and chlorophyll content. Therefore, adoption of SWI at 20 cm ×20 cm (square planting) with cultivars HD 2967 might be the best strategy for enhancing crop productivity and resource-use efficiency under the similar wheat growing conditions of India and similar agro-ecotypes of the globe.

Effect of Water Conservation and Nitrogen Reduction on Root Growth and Yield in Spring Maize in Typical Sand Interlayered Soil

Given the low water and fertiliser use efficiency and the extensive distribution of sand interlayered soil in the Hetao irrigation district (HID), this study aimed to investigate the effects of different irrigation and fertilisation regimes on root parameters and yield in spring maize grown in sand interlayered soil. A two-year field plot experiment was conducted using the spring maize “Ximeng 3358” under three irrigation and nitrogen levels. Root length (RL), surface area (RS), diameter (RD), volume (RV), and length density (RLD), grain yield, and water use efficiency (WUE) were examined. Root growth was inhibited at the sand layer, with approximately 72.46–87.37% of the roots concentrated in the 0–40 cm soil layer. Notably, the proportion of roots in the bottom layer was 24.61–87.37% higher than that in the sub-bottom layer. Moreover, RL, RS, RD, and RV peaked in the medium irrigation and nitrogen fertilisation (I2F2) treatment. Furthermore, correlation analysis showed that the root parameters were significantly positively correlated with yield and WUE, with RS being most correlated to yield and WUE. Roots at a narrow row spacing of 20 cm (NR20) and at a depth of 10–20 cm were strongly correlated with yield and WUE. Conclusively, the I2F2 treatment can be used as the optimal combination of water and nitrogen for sand interlayered soil farmlands.

Sensitivity of littleseed canary grass populations from Punjab, India, to clodinafop‐propargyl and isoproturon

AbstractLittleseed canary grass (Phalaris minor Retz.) is one of the most prevalent and troublesome annual grass weed species in wheat across the Indo‐Gangetic plains (IGP) of India, including Punjab. Littleseed canary grass has evolved resistance to different herbicide sites of action in the IGP region. A targeted field survey was conducted in 2018 and 2019 for seed collection of littleseed canary grass populations (total 94) across different districts of Punjab state prior to wheat harvest. The main objective of this research was to characterize the sensitivity response of collected littleseed canary grass populations to clodinafop‐propargyl (CP) and isoproturon (IPU) herbicides in whole‐plant dose‐response assays. Among all tested populations, 68 were found to be highly sensitive to CP, whereas all 94 populations were sensitive to IPU. Based on a 50% reduction in shoot dry biomass (GR50 values) and estimated sensitivity index (SI), 26 populations exhibited reduced sensitivity (SI of 2.2–4.4) to CP herbicide. The results also revealed that the littleseed canary grass populations with reduced sensitivity (SI ≥ 2.2) to CP had high sensitivity to IPU herbicide. Overall, these results suggested a high prevalence of littleseed canary grass populations with reduced sensitivity to CP herbicide in Punjab state. Diversified weed management strategies, including the use of alternative herbicides (both preemergence and postemergence), cultural (no‐till drill for wheat sowing and narrow row spacing), and mechanical (cutting of littleseed canary grass panicles prior to wheat harvest) practices should be adopted to control littleseed canary grass populations with reduced sensitivity to CP.

Impact of organic and conventional cultivation on seed quality of two soya bean varieties sown at different row spacings

Soya bean (Glycine max (L.) Merr.) is a legume valued for, among other things, the high nutritional value of its seeds, which contain around 40% protein with an excellent amino acid composition and a significant fat content. The study aimed to evaluate the protein, fat, fibre and amino acids content of the seeds of two soya bean varieties sown at different row spacings under organic and conventional growing conditions. The study showed that the conventional method of production has a more favourable effect on the soya bean’s protein content and the most amino acids, primarily essential amino acids. In organic cultivation, soya bean seeds were characterised by a higher content of fat and sulphur amino acids (methionine and cysteine). The research carried out indicates that the seeds of the Aldana variety, compared to the Merlin variety, have greater nutritional importance to humans due to a higher content of protein and almost all amino acids, including essential amino acids. Only a higher content of seed fat and tryptophan was evidenced in the Merlin variety. Row spacing did not significantly differentiate the assessed soya bean seed quality parameters. Only the amount of methionine was significantly higher when soya beans were grown at a narrower row spacing (22.5 cm).

Development of a line following autonomous spraying vehicle with Machine vision-based leaf density estimation for cherry tomato greenhouses

Traditional manual spraying systems and even modern automated ones often neglect the critical factors of plant growth stage and coverage density during spraying for plants, which can result in suboptimal yields. To address this issue, this study aims to describe the development of an efficient and affordable autonomous spraying vehicle (ASV) for application in cherry tomato greenhouses. The ASV integrates a visual autonomous spraying system (VASS) and a vehicle control system (VCS). The VASS uses leaf density signalling with machine vision and a vertical spray boom to target leaves for precision spraying application. Leaf density signalling is an algorithm developed to recognise and estimate leaf density by machine, simplifying the real-time determination of leaf density levels in plants. The performance of the algorithm demonstrates an accuracy of 84 % with an average video processing speed of 33.3 ms. The VASS is integrated into VCS to facilitate remote or autonomous navigation. The visual line-following system (VLFS) supports ASV in autonomously navigating between narrow-spaced rows in cherry tomato greenhouses, thereby automating the entire spraying process. The analysis of the comprehensive performance of the ASV and the comparative analysis with knapsack sprayers in field experiments are discussed and presented. Comparative analysis with manually operated sprayers demonstrates the better performance of the ASV. These experiments highlight the potential of the ASV to replace traditional manual spraying methods while enhancing spraying precision.

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.

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.

Improved photosynthetic performance under unilateral weak light conditions in a wide-narrow-row intercropping system is associated with altered sugar transport.

Intercropping improves resource utilization. Under wide-narrow-row maize (Zea mays) intercropping, maize plants are subjected to weak unilateral illumination and exhibit high photosynthetic performance. However, the mechanism regulating photosynthesis under unilateral weak light remains unknown. We investigated the relationship between photosynthesis and sugar metabolism in maize under unilateral weak light. Our results showed that the net photosynthetic rate (Pn) of unshaded leaves increased as the level of shade on the other side increased. On the contrary, the concentration of sucrose and starch and the number of starch granules in the unshaded leaves decreased with increased shading due to the transfer of abundant C into the grains. However, sink loss with ear removal reduced the Pn of unshaded leaves. Intense unilateral shade (40% to 20% normal light), but not mild unilateral shade (60% normal light), reduced grain yield (37.6% to 54.4%, respectively). We further found that in unshaded leaves, Agpsl, Bmy, and Mexl-like expression significantly influenced sucrose and starch metabolism, while Sweet13a and Sut1 expression was crucial for sugar export. In shaded leaves, expression of Sps1, Agpsl, and Sweet13c was crucial for sugar metabolism and export. This study confirmed that unshaded leaves transported photosynthates to the ear, leading to a decrease in sugar concentration. The improvement of photosynthetic performance was associated with altered sugar transport. We propose a narrow-row spacing of 40 cm, which provides appropriate unilateral shade and limits yield reduction.

Cultivation system influenced the critical period for weed control in cotton field

BackgroundThe critical period of weed control (CPWC) refers to the period of time during the crop growth cycle when weeds must be controlled to prevent yield losses. Ultra-narrow row (UNR) is a method of planting of cotton in rows that are 25 cm or less apart. Amongst cultural techniques for weed control, the use of narrow row spacing is considered to be a most promising approach that can effectively suppress weed growth and provide greater yields in cotton. This cultivation system can shorten the length of the critical weed-crop interference duration and results in greater yield. The current research aimed to determination of critical time of weed control in cotton (Gossypium hirsutum L.) under conventional and ultra-narrow row spacing conditions. Field experiments were arranged as factorial experiment in a randomized complete block design with three replications. Factors were cultivation system (conventional (50 cm row spacing) and ultra narrow row (25 cm row spacing and weed treatment including 30, 45, 60, and 75 days weeding after emergence during the growing season (weed free), and 30, 45, 60, and 75 without weeding (weed infested) in the growing season along with weedy and weed-free from sowing to harvesting. A four-parameter log-logistic model was fit to the two sets of relating relative crop yield to data obtained from increasing durations of weed interference and lengths of weed-free period.ResultsIn both years and cultivation systems, the relative yield of cotton decreased with the increasing duration of weed-interference but increased with the increasing duration of weed-free period. Ultra-narrow row cultivation delayed the beginning of the CPWC in cotton. Under ultra-narrow row condition, the CPWC ranged from 21 to 99 days after germination in 2021 and 23 to 91 days in 2022 based on the 5% acceptable yield loss. Under conventional cultivation CPWC ranged from 17 to 102 days after emergence in 2021 and 18 to 95 days after emergence in 2022.ConclusionsUnder both conventional and Ultra-narrow row conditions, weed interference reduces seed yield. Under ultra-narrow row condition, weed interference until 21.1–23.5 days after cotton emergence and under conventional condition, weed interference until 16.9–18.5 days after cotton emergence had not significant reduction on cotton yield.

Optimal planting pattern of cotton is regulated by irrigation amount under mulch drip irrigation.

It is of great importance to explore agronomic management measures for water conservation and cotton yield in arid areas. A four-year field experiment was conducted to evaluate cotton yield and soil water consumption under four row spacing configurations (high/low density with 66+10 cm wide, narrow row spacing, RS66+10H and RS66+10L; high/low density with 76 cm equal row spacing, RS76H and RS76L) and two irrigation amounts (CI:conventional drip irrigation; LI:limited drip irrigation) during the growing seasons in Shihezi, Xinjiang. A quadratic relationship was observed between the maximum LAI (LAImax) and seed yield. Canopy apparent transpiration rate(CAT), daily water consumption intensity (DWCI) and crop evapotranspiration (ETC) were positively and linearly correlated with LAI. The seed yields, lint yields, and ETC under CI were 6.6-18.3%,7.1-20.8% and 22.9-32.6%higher than those observed under LI, respectively. The RS66+10H under CI had the highest seed and lint yields. RS76L had an optimum LAImax range, which ensured a higher canopy apparent photosynthesis and daily dry matter accumulation and reached the same yield level as RS66+10H; however, soil water consumption in RS76L was reduced ETC by 51-60 mm at a depth of 20-60 cm at a radius of 19-38 cm from the cotton row,and water use efficiency increased by 5.6-8.3%compared to RS66+10H under CI. A 5.0<LAImax<5.5 is optimum for cotton production in northern Xinjiang, and RS76L under CI is recommended for high yield and can further reduce water consumption. Under LI, the seed and lint yield of RS66+10H were 3.7-6.0% and 4.6-6.9% higher than those of RS76L, respectively. In addition, high-density planting can exploit the potential of soil water to increase cotton yields under water shortage conditions.

Relationship between canopy coverage at the initiation of stem elongation and lodging in wheat

While lodging in wheat appears to correlate with the ratio of canopy coverage at the initiation of stem elongation (CC30), a mechanistic understanding of the relationship between lodging index and CC30 is lacking. The objective of this study was to examine more closely the relationship between lodging and CC30 and to identify the most effective sowing densities and/or planting patterns in reducing lodging. The CC30 was adjusted by varying the sowing density and planting pattern, i.e., wide vs narrow-spaced rows and altering the seed spacing within the row and by spread sowing. We found that CC30 was positively correlated with the lodging degree at maturity and was negatively correlated with internode dry weight per unit length. The CC30 for a sowing density of 3 g m−2 (which is about half the conventional sowing density in Japan) was low at a range of 28–75 %. In these treatments, CC30 was lowest under spread sowing where the spacing between plants was greatest. The yield of the 3 g m−2 spread-seed treatments was more than 500 g m−2. This yield is comparable to that of the other treatments even though the sowing density was much lower. The aboveground N accumulation at maturity of the 3 g m−2 spread-seed treatments was similar to that of the other treatments. As found in the spread-seed treatments, our results suggest that lowering CC30 by reducing the sowing density and/or by changing the planting pattern, increased the spacing between seedlings and thus helped to prevent lodging while still retaining high yields.

Effect of Row Spacing and Plant Density on Silage Maize Growth, Dry Matter Distribution and Yield

Maize growth in narrow rows provides a more uniform spatial arrangement, but it does not always lead to increasing yield. A four-year study was conducted to investigate the effect of row spacing on silage maize growth and yield during the growing season and at harvest time. A field experiment with conventional (0.70 m) and narrow rows (0.35 m) at a plant density of 92,000 plants ha−1 was evaluated in the years 2011–2014, and the interaction of row spacing × plant density (92,000 and 110,000 plants ha−1) was tested in 2013–2014. The narrow rows clearly demonstrated potential to support plant height and weight development, together with a higher stalk proportion, at around two months after seeding. However, these contrasts were lost in the later stages and at harvest time. Some potential for non-significantly higher dry matter yield (4.6–10.8%) was shown in the narrow rows in three years of the experiment, in association with lower losses in plant numbers, when compared to conventional row spacing. The potential of yield improvement in the narrow rows showed relationships with weather conditions during the second half of the growing season. In summary, under the growing conditions of the study region, narrow row spacing significantly promoted early plant development, but these effects did not persist until harvest, thus resulting in only limited success in yield improvement.

Summer pulses as sources of green manure and soil cover in the U.S. Southern Great Plains

Winter wheat (Triticum aestivum L.) – summer fallow rotations in the Southern Great Plains (SGP) have numerous sustainability issues, such as low precipitation use efficiencies and increased soil erosion. Replacing summer fallow with a legume grown as a green manure would help reduce soil erosion, improve precipitation use efficiency, and add nitrogen (N) credits for the subsequent wheat crop. A two-year field experiment evaluated the capabilities of three summer pulses: soybean [Glycine max (L.) Merr.], moth bean [Vigna aconitifolia (Jacq.) Marechal], and tepary bean [Phaseolus acutifolius (A.) Gray] to serve as green manures and soil cover. We examined their performance across two row spacings (38 and 76 ​cm) and two moisture regimes (rainfed and irrigated). Narrow row spacing (38 ​cm) provided greater canopy cover, aboveground biomass, and N accumulation than the broad row spacing (76 ​cm) during the early growing season. Among species, tepary bean demonstrated consistent and higher canopy cover early in the season. Soybean produced the highest aboveground biomass (5,327–8,855 ​kg ​ha−1) and N accumulation (115–269 ​kg ​ha−1) among the three pulses. Multilinear regression (MLR) models suggested that canopy height and canopy cover could estimate both aboveground biomass (R2 ​= ​0.62) and N accumulation (R2 ​= ​0.55) for tested pulses. Based on results, soybean was the most promising choice among tested pulses, considering its higher aboveground biomass and N accumulation. Modelling studies to simulate growth of these crops with long-term weather scenarios are encouraged to identify the most reliable cover crop for different areas of the SGP.

Interaction of genotype-ecological type-plant spacing configuration in sorghum [Sorghum bicolor (L.) Moench] in China.

Grain sorghum has been a significant contributor to global food security since the prehistoric period and may contribute even more to the security of both food and energy in the future. Globally, precise management techniques are crucial for increasing grain sorghum productivity. In China, with diverse ecological types, variety introduction occasionally occurs across ecological zones. However, few information is available on the effect of ecological type on genotype performance and how plant spacing configuration influences grain yield in various ecological zones. Hence, a series of two-year field experiments were conducted in 2020 and 2021 in four ecological zones of China, from the northeast to the southwest. The experiments included six widely adapted sorghum varieties under six plant spacing configurations (two row spacing modes: equidistant row spacing (60cm) mode and wide (80cm)-narrow (40cm) row spacing mode; three in-row plant spacings: 10cm, 15cm, and 20cm). Our results indicated that ecological type, variety, and plant spacing configuration had a significant effect on sorghum yield. Ecological type contributed the highest proportion to the yield variance (49.8%), followed by variety (8.3%), while plant spacing configuration contributed 1.8%. Sorghum growth duration was highly influenced by the ecological type, accounting for 87.2% of its total variance, whereas plant height was mainly affected by genotype, which contributed 81.6% of the total variance. All test varieties, developed in the south or north, can reach maturity within 94-108d, just before fall sowing in central China. Generally, sorghum growth duration becomes longer when a variety is introduced from south to north. A late-maturing variety, developed in the spring sowing and late-maturing regions, possibly could not reach maturity in the early-maturing region. The row spacing modes had no significant affect on sorghum yield, but the equal-row spacing mode consistently caused higher yields with only one exception; this might imply that equal-row spacing mode was more advantageous for boosting sorghum yield potential. In contrast, decreasing in-row plant spacing showed significant positive linear associations with sorghum grain yield in most cases. In addition, these results demonstrated that sorghum is a widely adapted crop and enables success in variety introduction across ecological zones.

Optimization of Operation Parameters of the Garlic Plant Divider and Lifter Mechanisms

The technology of the divider and lifter mechanisms of a garlic harvester using the depth limit, straw divide, and straw lift modes was studied in Lanling County, Shandong Province, China, according to the characteristics of high hardness, good uprightness and narrow row spacing of garlic planting. A test prototype of the divider and lifter mechanisms of the garlic harvester was designed and manufactured. Single-factor experiments and orthogonal regression experiments were carried out using the experimental factors of working speed, the angle of the divider, the height of the tip of the divider’s tooth from the ground, the ratio of the lifter’s speed to working speed and the length of the lifter’s tooth. The index was the success rate of feed. The results showed that the working speed, the angle of the divider and the length of the lifter’s tooth had a significant influence on the success rate of feed (p &lt; 0.05), but the experimental factors of the height of the tip of the divider’s tooth from the ground and the ratio of the lifter’s speed to working speed did not have a significant influence on the success rate of feed (p &gt; 0.05). The effects of the angle of the divider, the working speed, and the length of the divider’s tooth on the success rate of feed decreased in significance. When the working speed was 0.72 km·h−1, the length of the lifter’s tooth was 343.5 mm and the angle of the divider was 20°, the success rate of feed was the highest (98.18%). The research results are conducive to promoting high-quality and efficient combined harvesting of garlic in Lanling County, Shandong Province, China.

Increasing the productivity of rajma through proper sowing date and plant geometry

Rajma (Phaseolus vulgaris L.) cultivation is gaining popularity in Terai to Hills of Nepal. The poor plant establishment and yield due to the results of unsuitable sowing time and row spacing are the main reasons for lower productivity of it. Therefore, the date of sowing and row spacing trials were conducted in two consecutive years, 2017 and 2018 at the Grain Legumes Research Program, Khajura, Banke. A widespread and registered variety of rajma PDR 14 was used in the experiment. The experiment was laid out in a split-plot design with four sowing dates (a) 11th October, (b) 26th October, (c) 10th November and (d) 25th November as the main-factor, and three rows spacing (a) 30 cm, (b) 40 cm and (c) 50 cm as the sub-factor, consisted of three replications. The effect of the date of sowing on all the yield and yield attributing characters was found significant at a one percent significance level. Similarly, row spacing has resulted in a significant difference in grain yield. Rajma sown on 26th October (Kartik 9) produced 12, 38 and 64% higher grain yield than sown on 11th October, 10th November and 25th November, respectively. Moreover, rajma seeds sown on 26th October with 30 cm × 10 cm plant geometry produced the highest grain yield (2185 kg/ha). The narrow row spacing seemed well than the wider row in rajma production. There is a great potential to increase the production and productivity of rajma through an appropriate time of sowing and row spacing.