Twin Rows Research Articles

The Impact of Planting Technology on the Maize Yield

The three–year trials of the impact of the planting technology on the maize yield were carried out at the trial sites Jakšić and Tenja. The KWS Intelligens and KWS Kollegas hybrids were used in the research, planted at a standard row spacing of 70 cm, and in the twin rows with a spacing of 48 × 22 cm. In 2020, the highest average grain yield at the site Jakšić in standard planting, with the KWS Intelligens hybrid, was 12.064 t ha–1, and in the twin row planting an increase in yield of +4.17% was recorded. The KWS Kollegas hybrid had the highest difference in grain yield between a standard and twin row planting in 2021 of +7.52%, in favor of the twin row. At the site Tenja, slightly higher grain yields were recorded in all three years of research. The major difference in yield was recorded in 2020 with the hybrid KWS Kollegas, of +8.22%, or 1.115 t more grain, when planting in the twin rows in comparison with a standard planting. The statistical tests indicate that planting in the twin rows at both trial sites obtained statistically significant results in all three years of research concerning the grain yield ha–1, grain weight per ear, and grain moisture content.

Effect of plant density on total oil quality and fatty acid compositions in peanut (Arachis hypogaea L.) cultivars

Research in the Eastern Mediterranean Transition Region of Türkiye has demonstrated that plant density impact yield of peanut (Arachis hypogaea L.) cultivars differentially. It is suspected that interactions of plant density and cultivar could also impact oil quality and fatty acid composition when grown in this region. This topic has not been addressed in the country; therefore, the objective of this research was to determine if plant density can affect those variables. The study was conducted in 2020 and 2021 in the zone of Osmaniye to determine total oil content of kernels, and contents of oleic acid, palmitic acid, arachidonic acid, linoleic acid, stearic acid, and lignoceric acid, as well as iodine value and oleic/linoleic ratio for the cultivars Halisbey, Rigel, Aysehanım, NC 7, and Masal. Plant response was in most instances different regardless of plant populations made up of a single row planting pattern with rows spaced 70 cm apart (95.000 plants ha-1) compared with a twin row planting pattern with rows spaced 20 cm apart on 90 cm centers with an intra-row distance of 15 cm (148.000 plants ha-1). It is concluded that no differences in oil quality and fatty acid composition were noted when comparing cultivars established at various combinations of planting pattern and plant population, but there were notable differences among the cultivars.

Intraspecific competition in row spacings in soybean

The aim of this study is to assess the impact of various row spacings on the morphology, components of grain yield, and overall grain yield of soybean. The experiments were conducted over two planting seasons (2014/2015 and 2015/2016) using two planting dates (November and December) and two cultivars, FPS Urano RR and BMX Tornado RR. The row spacings tested were: 45 cm (wide row), 45 × 45 cm (cross row), 22.5 × 45 cm (twin row), and 22.5 cm (narrow row). Measurements included leaf area index and sunlight interception at R2 stage, as well as grain yield components and overall grain yield. Narrow rows, in addition to achieving canopy closure, also demonstrated enhanced sunlight interception at the R2 stage. However, the positive effect of increased sunlight interception on grain yield was only significant for the December planting date, with no notable difference observed for the November planting date. These findings imply that while narrow rows may offer advantages, particularly in later planting dates, their implementation should be carefully considered and may not consistently lead to increased grain yield, reinforcing the continued preference for conventional row spacing.

Assessing the effect of cultural practices on Mississippi corn production: 2. Grain composition

AbstractGlobal demand for corn (Zea mays L.) is increasing, and it remains one of the most consumed crops by both humans and animals due to its high calorie content. However, corn grain quality research is sparse and often focused only on a few selected influencing factors. Therefore, two side‐by‐side studies (Addition and Deletion) were conducted in 2020 and 2021 in Mississippi to assess the grain composition including protein, starch, oil, and moisture of corn under several management practices. A randomized complete block design was implemented in both experiments involving a complete factorial of three factors including two plant populations (32,000 and 40,000 seed acre−1), two‐row configurations (single and twin), and six combinations of nutrients plus fungicide application (NF). The trials differed based on the manner of NF applications. In the trial termed Addition, all NF treatments were added incrementally, whereas in the Deletion trial they were withheld in a stepwise manner. Conditional inference tree analysis was conducted to examine interaction effects among the three factors over 3 site‐years. Corn protein content ranged between 8.2% and 9.8% across all years and locations. All three factors and certain interactions significantly influenced both protein and starch content. Specifically, single row planting, 40,000 seeds acre−1, and higher rates of N resulted in higher protein content. Contrarily, the starch content was positively influenced by twin row, 32,000 seeds acre−1 and only N application. Single row configuration resulted in higher oil than twin rows. This study determined that different management factors have the potential to positively influence protein, starch, and oil. These management strategies could extend farmers profitability and provide superior products for industrial purposes with additional implications for livestock feed supplements.

Economic Evaluation of Twin Row Maize Planter: A Cost-Benefit Analysis

The adoption of innovative agricultural technologies plays a crucial role improving farm productivity and overall economic outcomes. This research article aims to evaluate the economic viability of twin row maize planters compared to conventional single-row planters. The study assesses the economic benefits, costs and profitability associated with the adoption of twin row planting in maize cultivation. The analysis incorporates factors such as yields improvement, input savings, labor requirements, and machinery costs, providing valuable insights for farmers. Annual utility of mini tractor and the machine was considered as 1000 and 200 hrs respectively. Field efficiency of developed twin-row planter at 1.5 to 2.5 kmh-1 speed of operation was 76.9 to 87% respectively. The payback period calculated on year basis for planter was 1.78 years. Cost of operation by twin row maize planter can save up to 20% as compared to the traditional methods.

Influence of planting pattern on peanut ecosystem daytime net carbon uptake, evapotranspiration, and water-use efficiency using the eddy-covariance method

Peanut is planted in a pattern of either single or twin rows in Georgia, USA. However, limited attention has been paid to the impact of planting pattern on the carbon footprint and how the net carbon uptake is intertwined with the amount of water used to determine the ecosystem water-use efficiency (WUE) in peanut. This paper reports on the relationship between the amount of carbon produced to the amount of water used in peanut, carbon dioxide flux, and crop evapotranspiration of peanut in a single- or in a twin-row planting pattern measured using the eddy-covariance method. To the best of our knowledge, the present study is unique in that it examines for the first time the effect of planting pattern on the net carbon uptake and WUE. The two-year study took place in contrasting weather conditions with the 2016 year experiencing a higher vapor pressure deficit and lower precipitation than in the 2018 year. In this study, field-scale daytime net carbon ecosystem exchange (CO2 fluxes), ET and WUE of single- and twin-row peanut were compared using the eddy-covariance technique. Results showed that in 2018, both the net carbon uptake from the atmosphere and the WUE of twin-row peanut were significantly greater than those in the single-row peanut by 7-10% and ~9% respectively, for pod filling and seed maturity growth stages (aGDD 1000-2000 and aGDD > 2000). In 2016, the net daytime carbon uptake and WUE of peanut were similar for both planting patterns during pod filling (aGDD 1000-2000). Higher precipitation and lower VPD in 2018 likely resulted in greater peanut yield in twin-row as compared to single-row with abundant precipitation. Owing to the fast canopy growth rate in twin-row peanut, results suggest that during the vegetative stage (aGDD<500) in 2016, both daytime net carbon uptake from the atmosphere and WUE were considerably greater in twin-row than single-row by 32% and 27%, respectively. Given that in both years, the ET from both planting patterns was similar, it appears that the determination of WUE in both planting patterns was more impacted by changes in daytime net carbon uptake than evapotranspiration. The results of this study suggest the possibility that the higher WUE at the critical stages of twin-row peanut in 2018 are likely to lead to greater yield than single-row peanut. This should be confirmed with further year-to-year investigations.

Effect of irrigation regimes and planting patterns on maize production in humid climates

AbstractTwin‐row planting in maize (Zea mays L.) has potential for reducing plant‐crowding stress for optimizing grain yield and resource use. A study was conducted in 2020 and 2021 on a Dundee silt loam in the Lower Mississippi Delta (LMD) region of the United States to evaluate maize grain yield and irrigation water use efficiency (IWUE) in single‐row (SR) and twin‐row (TR) planting patterns with same seed rate under four irrigation regimes: rainfed (RF), all‐furrow irrigation (FI), alternate‐furrow irrigation (AFI), and every third‐furrow irrigation (TFI). The TR enhanced grain yield by 9.2% in 2020 and 10.9% in 2021 over the SR system. The average final plant density at the reproductive phase was highest under AFI (73,900 ha−1) and lowest under RF (70,480 ha−1). Across all irrigation regimes, the leaf area index was significantly higher in the TR system. Average grain yields under SR were 10.01, 10.44, 9.48 and 9.10 Mg ha−1, respectively, in FI, AFI, TFI and RF; average grain yields under TR were 11.58, 11.32, 10.13 and 9.91 Mg ha−1. The AFI and FI recorded similar grain yields. The IWUE was highest in TR planting (0.028 kg m−3), followed by SR planting (0.024 kg m−3) under AFI. The IWUE of TFI in TR planting was 0.020 kg m−3 and in SR was 0.011 kg m−3. Economic analysis revealed that the TR‐FI and TR‐AFI had average profits of 446 and 432 US$ ha−1, respectively. The study suggests that maize producers in the LMD can save a significant amount of irrigation water without compromising grain yields by adapting the AFI‐TR system.

Fenofases de floração e caracterização morfoagronômica de cultivares de Palma de Santa Rita

Abstract The characterization of flowering phenophases and morphoagronomic knowledge is important for crop management and harvest programming. This study aimed to evaluate the duration of reproductive phenophases and conduct morpho-agronomic characterization of gladiolus cultivars. Two experiments were conducted, one in a shaded environment and the other in a full sun environment. A split-plot design in randomized blocks was used, which consisted of the planting system with single rows and twin rows in the plots and the cultivars (White Goddess, Traderhorn, Peter Pears, and Gold Field) in the subplots. The reproductive phenophases, plant development and productivity of each cultivar were evaluated. The flowering cycle lasted from 58 to 65 days when the cultivars were grown in the shaded environment, while the duration of this cycle ranged from 78 to 87 days in the full sun environment. The yield of the Gold Field cultivar was significantly higher when grown in twin rows compared to single-row planting. A shaded environment and twin-row planting are the recommended conditions for the cultivation of gladiolus in the state of Mato Grosso since they promote better stem development and early flowering of the cultivars. The Peter Pears and Gold Field cultivars are recommended for cultivation in the region due to their greater production of marketable stems.

EFFECT OF PLANT DENSITY ON YIELD AND QUALITY OF PEANUT (Arachis hypogaea L.) CULTIVARS

Plant density can have a major impact on peanut (Arachis hypogaea L.) yield. Information is limited in the Eastern Mediterranean Transition Region of Turkiye on growth, development, and yield of peanut cultivars based on plant density. To address this limitation, the cultivars Aysehanim, Rigel, Halisbey, Masal, and NC 7 were established in a single row planting pattern consisting of rows spaced 70 cm apart with an inter-row plant distance of 15 cm (95.000 plants ha-1) versus a twin row planting pattern consisting of rows spaced 20 cm apart on 90 cm centers with an intra-row distance of 15 cm (148.000 plants ha-1). The interaction of cultivar × plant density was significant for most variables. Irrespective of cultivar, establishing a plant population of 148.000 plants ha-1 in the twin row planting pattern resulted in greater pod yield than the single row planting pattern with a plant density of 95.000 plants ha-1. Pod yield was similar for Rigel, Masal, and NC 7 in the twin row planting pattern and exceeded that of Aysehanim and Halisbey. Conversely, yield of Rigel and Halisbey was similar in the single row pattern and exceeded yield of Aysehanim and NC 7.

Row spacing and irrigation management affect soybean yield, water use efficiency and economics

Declining water levels in the Mississippi River Valley Alluvial Aquifer necessitates research on the management practices that can reduce irrigation water use and improve irrigation water use efficiency. A three-year field study from 2019 to 2021 evaluated the effects of row spacing and irrigation management on soybean seed yield and quality, irrigation water use efficiency (IWUE), water productivity (WP), and profitability. Soybean was planted in two row spacings [single- (SR) and twin-row (TR)] and irrigated with three different methods [every row irrigated (ERI), alternate row irrigated (ARI), non-irrigated (NI)]. Soybean yields were increased with application of irrigation either as ERI or ARI as compared to NI in all three years ranging from 20% to 79%. The ERI had 20% increase in yield over ARI in 2021, whereas no significant differences were found between ERI and ARI in 2019 and 2020. Averaged over row spacing, IWUE was 66–91% greater with ARI compared to ERI. Only 2021 showed an increase (34%) in WP with irrigation applied as ARI than NI. Differences in rainfall amount among years and amount of irrigation applied under different treatments affected the soybean yields. Soybean yield showed reduction by 0.37–1.2 kg ha−1 with each unit increase in cumulative stress (kPa-days) for soil moisture potential drier than the −40 kPa on very fine sandy loam soils. Twin-row soybean had higher expected returns in all cases except for the NI and ERI in 2021. The TR soybean produced the greatest average risk-return than other treatments. The ARI with TR had the second highest overall risk-return trade-off. The ARI resulted in an equivalent risk-return production system as ERI for SR soybeans. Alterations in furrow irrigation methods could be more beneficial than row spacing to improve soybean productivity and IWUE.

Photosynthetic Response of Soybean and Cotton to Different Irrigation Regimes and Planting Geometries.

Soybean [Glycine max (L.) Merr.] and cotton (Gossypium hirsutum L.) are the major row crops in the USA, and growers are tending toward the twin-row system and irrigation to increase productivity. In a 2-year study (2018 and 2019), we examined the gas exchange and chlorophyll fluorescence parameters to better understand the regulatory and adaptive mechanisms of the photosynthetic components of cotton and soybean grown under varying levels of irrigations and planting geometries in a split-plot experiment. The main plots were three irrigation regimes: (i) all furrows irrigation (AFI), (ii) alternate or skipped furrow irrigation (SFI), and iii) no irrigation or rainfed (RF), and the subplots were two planting patterns, single-row (SR) and twin-row (TR). The light response curves at vegetative and reproductive phases revealed lower photosynthesis rates in the RF crops than in AFI and SFI. A higher decrease was noticed in RF soybean for light compensation point (LCP) and light saturation point (LSP) than that of RF cotton. The decrease in the maximum assimilation rate (Amax) was higher in soybean than cotton. A decrease of 12 and 17% in Amax was observed in RF soybean while the decrease is limited to 9 and 6% in RF cotton during the 2018 and 2019 seasons, respectively. Both stomatal conductance (gs) and transpiration (E) declined under RF. The moisture deficit stress resulted in enhanced operating quantum efficiency of PSII photochemistry (ΦPSII), which is probably due to increased photorespiration. The non-photochemical quenching (NPQ), a measure of thermal dissipation of absorbed light energy, and quantum efficiency of dissipation by down-regulation (ΦNPQ) increased significantly in both crops up to 50% under RF conditions. The photochemical quenching declined by 28% in soybean and 26% in cotton. It appears soybean preferentially uses non-photochemical energy dissipation while cotton uses elevated electron transport rate (ETR) under RF conditions for light energy utilization. No significant differences among SR and TR systems were observed for LCP, LSP, AQE, Amax, gs, E, ETR, and various chlorophyll fluorescence parameters. This study reveals preferential use of non-photochemical energy dissipation in soybean while cotton uses both photochemical and non-photochemical energy dissipation to protect PSI and PSII centers and ETR, although they fall under C3 species when exposed to moisture limited environments.

Değişik Bitki Sıklıklarının Tek ve Çift Sıralı Ekimlerde Hibrit Mısırın (Zea Mays L.), Büyüme ve Verim Özelliklerine Etkisi

This research was conducted to compare single and twin-row planting patterns and to determine optimum plant density for hybrid maize varieties (DKC5364, P0573), grown in Western Blacksee conditions of Türkiye, in the main crop growing season in 2020. The experimental design was a randomized complete block in a split-split plot arrangement with three replications. Hybrid maize varieties were in the main plots, planting patterns (single row (70 cm) and twin row (70-20cm) were in the split plots and plant densities of 8, 9, 10, 11 and 12 plants/m2 were in the split- split plots. In the current study, plant height, first ear height, stem diameter, ears number per plant, ear length, ear diameter, and ear weigth were examined. Effects of varieties, planting patterns and plant densities on plant heights, first ear heights, ears numbers per plants and ear weigths were statistically significant. Higher values were observed at DKC5364 maize variety than P0573 variety for examined characteristics. The most suitable plant densities were determined as 11 plants/m2 for grain production and 12 plants/m2 for silage production in twin row plantig in Western Blacksee conditions of Türkiye

Evaluation of Advanced Kenyan Barley (Hordeum vulgare L.) Genotypes for Resistance to Stem Rust (Puccinia graminis Pers:.Pers. f.sp tritici Eriks. & E. Henn.) Race Ttksk and Its Variants

Stem rust caused by Puccinia graminis Pers:.Pers. f.sp tritici affects all the aerial parts of wheat and barley plants leading to yield losses. The objective of this study was to determine the level of resistance in advanced Kenyan barley lines to stem rust race TTKSK and its variants. The greenhouse and field experiments were laid in complete block design and randomized complete block design respectively with all experiments replicated three times. The experiments were conducted at Kenya Agricultural and Livestock Research Organization- Njoro. In the greenhouse experiment, forty genotypes were sown in perforated plastic pots and when the seedlings attained two-leaf stage, stem rust isolate collected from wheat variety, KS Mwamba was used to inoculate the genotypes. In the field, forty genotypes were sown in a one meter twin rows of each genotype were planted and all agronomic practices implement except management of stem rust disease. Infection types (IT) on the seedlings were observed and data collected following a scale described by Stakman et al. 1962. Disease severity data was collected according to modified Cobbs scale and then subjected to Area Under Disease Progress Curve (AUDPC). All genotypes showed immunity to moderate resistance at seedling level ranging from 0 to 2+. Adult plant reactions to race TTKSK and its variants ranged from an overlap of moderately resistant (MR) to susceptible (S). In all genotypes AUDPC ranged from 225.83 to 887.92 for under this study and the Coefficient of Infection ranged from 13 to 47. High levels of slow rusting were observed in only 12.5% of the genotypes tested while 10% of the genotypes had low levels. 77.5% of the genotypes had moderate levels of slow rusting. The genotypes with high levels of slow rusting can be advanced for release as varieties or be included in barley breeding.

Variation of Epiphytic Flora Affecting Silage Quality in Pure and Mixed Mung Bean and Sweet Sorghum

This study was carried out to determine the microorganism population affecting silage quality of sweet sorghum and mung bean cultivated with different sowing patterns as mixture or sole crop. Twin row (20×55 cm row spacing), narrow row (55 cm row spacing) and conventional row (75 cm row spacing) were used as mixture sowing patterns. The mixtures were formed based on the plant densities and alternative row numbers of sweet sorghum and mung bean. Sowing was made on alternation rows of 1 row mung bean plus 1 row sweet sorghum (R1:1) and 1 row mung bean plus 2 rows sweet sorghum (R1:2). In pure and mixed cultivations, the plant density of sorghum was 14 plants m-2 while the plant densities of mung bean were 14, 21 and 28 plants m-2. The experiment was planned as two-factors (sowing patterns and mixtures) and was arranged in randomized blocks according to the split plot design with 3 replications. Pure and mixed plants were harvested when the sweet sorghum plant reached the dough stage. Lactic acid bacteria, enterobacteria and yeast and mold populations in the plant epiphytic flora were investigated under experimental factors. There were significant effects of the main factors and their interactions on the plant epiphytic microorganisms. According to the results obtained from the current study, mixed cultivation of sweet sorghum and mung bean in conventional row pattern improved the desired lactic acid bacteria population for silage quality, while reducing the undesirable enterobacteria and yeast and mold population for silage quality. It was determined that the (R1:2) MB14+SS14 mixed cultivation system was the most suitable mixture in conventional row pattern in terms of high lactic acid bacteria population.

Effect of nitrogen topdressing on planting density response of grain yield in maize with different planting pattern cultivation

AbstractWe investigated the maize grain yield in response to nitrogen topdressing at different planting densities and planting patterns (twin row, TR; narrow row, NR; and conventional row, CR) over 3 years using early‐maturing cultivars. The P8025 grain yield was higher with a nitrogen topdressing of 6 g/m2 (N6) than without a nitrogen topdressing (N0) at all planting densities in 2017, 2018, and 2019. The difference between the nitrogen topdressing treatments was largest at a planting density close to 10 plants per square meter, which resulted in the highest grain yield in the N0 plot. The rank order for the grain yields among planting patterns was TR ≥ NR > CR in the three analyzed years. Changes in grain yield associated with planting densities followed significant negative quadratic regression curves for all planting patterns. In both the N0 and N6 plots, the grain yield response to planting density was more stable for TR cultivation than for CR and NR cultivation. The rank order for the nitrogen use efficiency (NUE) among planting patterns was TR ≥ NR ≥ CR. The differences in the NUE among planting patterns were higher at higher planting densities. The high NUE observed for TR and NR cultivation was due to the high topdressed nitrogen absorption rate (Nab) at a planting density less than 8.9 plants per square meter as well as the efficiency of the grain yield increase resulting from absorbed nitrogen (Ngy) at a planting density greater than 10.3 plants per square meter. The higher NUE for TR cultivation than for NR cultivation at 12.1 plants per square meter was because of a difference in Ngy and was unrelated to Nab. These results suggest that the improvement of planting pattern (TR, NR) can enhance the effect of topdressed nitrogen on grain yield in maize due to the increase of Nab or Ngy according to the planting density.

Study of stereochemical crystallization of racemic mixtures of [5] and [7]thiaheterohelicene molecules on Ag(111) surface by scanning tunneling microscopy and Raman scattering spectroscopy

The crystallization of a racemic mixture of [5] and [7]thiaheterohelicene molecules into two-dimensional highly ordered molecular domains on a Ag(111) surface was investigated by scanning tunneling microscopy (STM) at 80 K. We observed that the crystallization of both thiaheterohelicene molecules on a Ag(111) surface was strongly affected by stereospecific interactions resulting from different numbers of aromatic rings incorporated into the helical skeletons of molecules. [5]Thiaheterohelicene molecules crystallized predominant into a few racemate polymorphic molecular domains, allowing us to obtain high-resolution STM images with the unambiguous identification of the absolute handedness of enantiomeric species. In contrast, the stereochemical chiral interactions among [7]thiaheterohelicene molecules led to the formation of one type of racemate molecular domain consisting of self-assembled zigzagged twin rows. X-ray photoelectron spectroscopy investigation strongly suggests weak interaction between thiaheterohelicene molecules and Ag(111) surface and lack of formation the S-Ag chemical bond. Surface-enhanced Raman spectroscopy combined with theoretical calculation based on a density functional theory was applied to the chemical verification of molecules adsorbed on a plasmonic silver surface for future tip-enhanced Raman spectroscopy.

Profitability of twin‐row planting and skip‐row irrigation in a humid climate

AbstractWe assessed the potential profitability of twin‐row (TR) planting geometry as a water productivity‐enhancing practice and of skip‐row irrigation (SRI) as a water‐conserving practice in furrow‐irrigated cotton (Gossypium hirsutum L.) and soybean (Glycine max L.). Data from agronomic experiments carried on Dundee silt loam soils indicate that, on average, TR planting increases profitability by US$344 ha−1 for all‐row irrigated (ARI), $401 ha−1 for SRI, and $334 ha−1 for rainfed (RF) cotton. For soybean, the gains were $178 ha−1 for ARI irrigated, $178 ha−1 for SRI, and $121 ha−1 for RF. Converting from ARI to SRI irrigation can conserve 88 mm of irrigation water on average for cotton and 91 mm of irrigation water on average for soybean, while improving cotton profits by $55–113 ha−1. Soybean growers can expect a reduction in profits from SRI of ∼$11 ha−1. Incentive payment for soybean growers of ∼$0.132 mm−1 of saved water would compensate farmers for the expected losses of adopting SRI in the Delta of Mississippi.

Sustavi sjetve kao čimbenik prinosa zrna u proizvodnji suncokreta

The paper presents the results of a triennial study of the sowing system influence on the yied, grain weight per head, plant set per ha and of the grain moisture of a medium-early sunflower hybrid . Standard sowing was performed with the PSK OLT sowing machine at a row spacing amounting to 70 cm, while a twin row sowing was performed with the MaterMacc Twin Row-2 sowing machine at a row spacing of 22*48 cm. Both sowing machines were adjusted according to the ISO standard 7256/1 and 7256/2, with a high QFI index (PSK OLT: 96.32 %; MaterMacc Twin Row-2: 93.93 %). The research was conducted at the Gorjani Experimental Field on psudogley bearing the textured markings of a silty loam, with a weak acid reaction and a small amount of humus. An analysis of variance determined a statistical significance of the sowing system on the grain yield and the grain mass per sunflower head. Sowing in twin rows achieved the higher yields for all three research years : 19.59% in 2017, 19.11% in 2018, and 18.45% in 2019. Plant density was not statistically significantly affected by the sowing systems and vegetation year, but the grain moisture was statistically significantly different between the analyzed research years .

Influence of planting date, row spacing, and reduced herbicide inputs on peanut canopy and sicklepod growth

AbstractSicklepod [Senna obtusifolia (L.)] is one of the most problematic weed species for peanut production in the southeastern USA. A two‐year study was conducted to evaluate the influence of peanut planting date and row spacing on sicklepod growth. Planting date was the main plot factor with early (early May), mid‐ (mid‐May), or late (early June) timings. Row spacing was the subplot factor with single row and twin rows at 13, 18, or 23 cm. For minimal herbicide use, pendimethalin was applied at peanut planting and 2,4‐DB was applied at 6 wk after planting. Peanut on twin rows at 18 and 23 cm achieved canopy closure 2 wk earlier than the single or the 13‐cm twin‐row. In 2019, sicklepod height was similar across all planting dates, while in 2020 height decreased in the order of late > mid > early planting. Sicklepod biomass in early planting was greater compared with mid and late planting in 2019, whereas biomass was greater in late planting compared with early and mid‐planting in 2020. Peanut yield was 50% greater in early and mid‐planting compared with late planting in 2019, while yield was 18% lower in the single row compared with the twin rows in 2020. The differences between the two years were attributed to greater humidity and heavy rainfall during 2020 (137 cm) compared with the 2019 (77 cm) season. We conclude that peanut planted on 18‐ or 23‐cm twin rows during the mid‐planting date has the potential to maintain yield and suppress sicklepod.

Decoding ionic conductivity and reordering in cation-disordered pyrochlores.

The ordered structure A2B2O6O' in pyrochlores engenders twin rows of inequivalent anion sublattices each centred on alternating cations. While it is known that cation antisite disorder augments the ionic conductivity by several orders of magnitude, the local cation environment around the anions and the dynamic anion reordering during the cation disordering are not well-elucidated. Using atomistic simulations on Gd2Zr2O7, we first show that the anions engage in concerted hops to the neighbouring tetrahedral sites mostly along with the 〈1 0 0〉 direction while completely avoiding the octahedral sites. While the initially vacant 8a sites start accommodating oxygen ions with increasing cation disorder, they show noticeable reluctance even at significant levels of disorder. We have also tracked both the distribution of available oxygen sites following random cation disorder, which is dependent only on cation disordering, and the probability of occupation of these sites. Interestingly, the available oxygen sites show a non-monotonic dependence on the number of B ions in the nearest neighbouring shell while the occupation probability of all the available oxygen sites increases monotonically. A tetrahedral oxygen site thus has a better probability of being occupied when it has a greater number of second neighbour B ions. This article is part of the Theo Murphy meeting issue 'Understanding fast-ion conduction in solid electrolytes'.