Days After Seeding Research Articles

Rapidly count crop seedling emergence based on waveform Method(WM) using drone imagery at the early stage

Effectively monitoring seedling emergence is critical to identify missing cotton seedling at early stages, allowing the prompt replenishment of the seedlings to maintain crop yield. However, traditional manual inspections have the limitations with low efficiency, poor timeliness, and large counting errors. Although UAV imagery has been applied in seedling monitoring, there are still chance in cotton seedling monitoring under complex environment conditions. Therefore, there is a urgent need for an efficient, rapid, and low-cost method for monitoring early seedling emergence in cotton crops. This study utilizes RGB images of early seedling emergence captured from an unmanned aerial vehicle (UAV) at a flight height of 10 m and a resolution of 0.33 cm in Shihezi, Xinjiang, on 7 and 12 days after seeding (DAS). The modified Hough transform method is constructed for line detection, and crop rows are subsequently extracted from the lines and masked images. After masking, the waveform is extracted from the excess green index (ExG) greyscale map and smoothed to determine the peaks. Seedlings are counted and located by numbering and positioning the peaks, meanwhile their coordinates and distance determine the number and location of missing seedlings. Images with varying resolutions (ranging from 0.33 to 2.5 cm) and intensity changes (0.8 to 1.2) verify the accuracy and efficiency of the proposed waveform method(WM). The results shown that at 7 DAS, the root mean square error (RMSE) is less than 2.0 plants/row, the relative root mean squared error (RRMSE) is less than 2 %, and the coefficient of determination (R2) is stable at 0.95–0.96 when the resolution is below 1.0 cm. The RMSE, RRMSE and R2 fluctuate more when the resolution is less than 1.0 cm. At 12 DAS, the counting accuracy is stable under different conditions, and the RMSE and RRMSE are distributed smoothly over the range of 1.76–4.39 plants/row and 1.29–5.47 % with different resolutions. The R2 is in the range of 0.88–0.97, RRMSE is 1.90–3.39 % and the RMSE is 1.65–2.90 plants/row under different intensities. The results of cotton seedling counting using the waveform method are less affected by image resolution and intensity changes. Therefore, the proposed WM provides efficient, accurate, and automatic counting for cotton seedlings in response to complex weather conditions. Furthermore, it would give a novel approach to accurately countequally spaced row-sown crops based on UAV images.

Effect of Polythene Covering on Seedling Quality and It’s Carryover Effect on Field Duration and Grain Yield of Rice

Boro rice cultivation is often limit due to lack of a farmer's friendly technique for raising quality seedling in irrigated ecosystem. Experiment was conducted in Boro 2019-20 at R/S Rangpur to compare different polythene covering treatment on raising quality seedling of BRRI dhan88 and BRRI dhan89 and to measure it’s carryover effect on growth duration and grain yield of rice. The treatments were as T1: Day polythene cover (from10:00 am to Sunset), T2: Night polythene cover (Sunset to Sunrise), T3: Day-night polythene cover but round shape opening (30 cm diameter) at both sides and T4: No polythene cover (control). Seedbed was covered by transparent polythene from seeding to 30 days after seeding (DAS). Seedling strength was higher on 01 December seeding than 15 December in both the tested varieties. Day cover always had the lowest seedling strength in both varieties. Day-night polythene cover treatment (T3) produced significantly tallest seedling than other polythene covering treatments for both the plantings dates. Seedling mortality was higher in 30 January planting than 15 January planting for both the tested varieties due to prevailing low temperature (below 10°C for eight days). In 15 January planting, BRRI dhan88 and BRRI dhan89 produced higher number of tillers with day cover and night cover treatment, respectively. In 30 January planting, BRRI dhan88 produced higher tiller with day-night and control treatment but day cover had the lowest. Tiller production rate was sharply increased from 35 – 45 DAT and then decreased. Up to 45 DAT, it was statistically similar in both the varietiers with all treatments. Although, tiller number was higher in T1, T2 and T4 than T3 but productive tiller (%) was satistically similar among the treatments for both the varieties and planting dates. There was no significant difference in grain yield among the treatments for planting dates and varieties. Day-night polythene cover treatment (T3) reduces growth duration by 2-3 days over other treatments. This treatment (T3) is farmer's friendly for raising quality seedling in cold prone areas of Bangladesh. Bangladesh Rice J.26 (1): 59-68, 2022

Seeding and Harvesting Times and Climate Conditions Are Important for Improving Nitrogen and Fiber Contents of Green Manure Sunn Hemp

The efficient use of green manure enhances sustainable nitrogen (N) cycling in agroecosystems. Appropriately utilizing the differences in N and fiber of green manure between cultivars or harvesting times strengthens the N use efficiency for subsequent crops. Therefore, it is necessary to clarify these differences. We clarified differences in nitrogen and fibers from four sunn hemp (Crotalaria juncea L.) commercial cultivars at two harvesting times after spring and summer seeding for three years. Only a few significant differences were found for any components between the four commercial cultivars. Although sunn hemp produced almost no flowers after the May seeding, the earliest flower opened at 50 days after seeding (DAS) and then significantly increased by 60 DAS (p < 0.05), after the July seeding. Sunn hemp DMY at 60 DAS had significantly larger values than those at 50 DAS all three years after the May and July seedings (p < 0.01). Significant differences between 50 DAS and 60 DAS were also observed for more than two years for the sunn hemp total carbon (TC), total nitrogen (TN), C/N ratio (CN), nitrate N (NO3-N), acid detergent fiber (ADF), and neutral detergent fiber (NDF) (p < 0.05). The sunn hemp N and ADF yields were significantly greater at 50 DAS than at 60 DAS in 2019 and 2020 (p < 0.05). These results suggest that the seeding and harvest time are important for decomposition estimations, although the differences between cultivars with equivalent flowering characteristics were not worth considering. Additionally, significant differences between years were found for all measurements except for NDF after the July seeding. This result suggests that the yearly effect of the difference in weather conditions, which causes differences in the yield, nitrogen, and ADF contents, is also an important factor for decomposition.

A bioassay to determine Poa annua responses to indaziflam

Herbicide resistance within Poa annua is widespread in managed turfgrass systems. In 2020, a P. annua collection from a golf course in the southeastern United States was reported to be resistant to indaziflam as well as six other mode-of-action groups. This first report in 2020 suggests that turfgrass managers would benefit from a bioassay to screen other collections with putative indaziflam resistance. A dose-response experiment was conducted with ten concentrations of indaziflam (0, 250, 500, 667, 1000, 1143, 1333, 2000, 4500, and 9000 pM) in Gelrite® culture during 2021 and 2022. An herbicide-susceptible (S1) collection of P. annua, a resistant standard (Site 3A), and a collection with putative resistance to indaziflam (Site 18) were included in this experiment. Petri dishes were filled with 80 mL of Gelrite® (3.75 g L−1) containing technical grade (≥ 98%) indaziflam and rifampicin (1000 µg mL−1). Each plate was sealed with parafilm after placing 15 seeds of a single collection on the Gelrite® surface. At 14 days after seeding (DAS), the length of the radicle (mm) protruding from each seed was recorded with digital calipers. Indaziflam concentrations required to reduce root growth by 70% (EC70) were calculated via non-linear regression. Statistically significant differences were detected among P. annua collections with the EC70 values for the herbicide-susceptible collection measuring 708 pM [95% confidence interval (CI) = 656 to 764 pM] compared to 2130 pM (CI = 1770 to 2644 pM) for Site 3A and 4280 pM (CI = 3464 to 5442) for Site 18. Given that resistant collections exhibited longer root length in the absence of herbicide, confocal microscopy analysis was used to explore differences in root cell count among resistant and susceptible P. annua collections; however, few differences in cell count were detected. Overall, these findings indicate that a discriminatory dose of 708 pM (95% CI = 656 to 764 pM) can be used to differentiate among susceptible and resistant P. annua collections from field sites where poor control is observed following broadcast applications of indaziflam.

Influence of Weed Control Techniques on Weeds, Yield, and Economics of Dry Direct-seeded-Drip-irrigated Rice under Philippine Conditions

The use of herbicides in combination with hand weeding has been shown to be effective against a variety of weeds in irrigated and rainfed wet direct-seeded rice in the Philippines. In the case of dry direct-seeded-drip-irrigated rice; however, these aspects are not known. A study was conducted to determine the influence of two weed control techniques on weeds, yield, and economics of dry direct-seeded-drip-irrigated rice under Philippine conditions. Four treatments – [T1] unweeded; [T2] application of pre-emergence herbicide using pretilachlor, followed by two times hand weeding; [T3] application of post-emergence herbicide using bispyribac-sodium, followed by two times hand weeding; and [T4] weed-free using the sequential application of pre- and post- emergence herbicides followed by six times hand weeding – were tested and arranged in RCBD with three repetitions. T1 has the highest weed density and biomass with lower grain yield (901.8 kg ha–1) but no net income. T2 and T3 had lower weed biomass than T1 but could not be compared with T4, where no weed density and biomass were recorded at 15, 30, and 45 DAS (days after seeding) in both dry and wet seasons. Grain yields at T2 (3,794.4 kg ha–1) were not significantly different from T3 (4,341.3 kg ha–1) except when compared with T4 (5,7245 kg ha–1). Net income in T2 was higher by PHP 20,575.1 over T1 and T3 by PHP 9,831.4 over T2. T4 had the highest grain yield among all treatments and achieved an advantage of PHP 45,272.1, 24,697.0, and 14,865.7 over T1, T2, and T3, respectively, in terms of net income. Herbicide application followed by hand weeding reduced weed growth and improved rice yield and net income. The combination of pre- and post-emergence herbicides followed by six times hand weeding was much more effective at suppressing weeds and achieving higher grain yield and net income.

Assessment of oxyfluorfen-tolerant rice systems and implications for rice-weed management in California.

Weeds are a significant barrier to rice production in California, exacerbated by lack of chemical control options and herbicide-resistance in persistent aquaphilic species. Oxyfluorfen-tolerant rice, created at the Rice Experiment Station (RES) in Biggs, California, was developed to provide an agronomic program for managing problematic grass and sedge rice-weeds including Oryza sativa f. spontanea Roshev. (weedy 'red' rice). Hand-pulling is the most common removal method for O. sativa spontanea because there are no herbicides registered for this pest in California. Oxyfluorfen was used in combination with oxyfluorfen-tolerant rice in 2019 and 2021 field studies to evaluate rice injury and weed control efficacy on prevalent rice-weed species. Additional studies were conducted in 2021 on University of California Davis campus to determine pre-emergent oxyfluorfen efficacy on four California O. sativa spontanea accessions. Fields studies indicated minimal crop injury in the first 28 days after seeding (DAS), but no observable injury at 60 DAS in both years. Weed control with oxyfluorfen alone was 87% or greater for all weeds rated with the exception of Schoenoplectus mucronatus (L.) Palla (ricefield bulrush), and Leptochloa fascicularis (Lam.) A. Gray (bearded sprangletop) in both years. All O. sativa spontanea exposed to soil-applied oxyfluorfen successfully emerged through the soil surface, but became completely necrotic 28 days after flooding. Oxyfluorfen-tolerant rice system was demonstrated to be a viable management strategy for California rice growers who struggle with grass- and sedge-weed control as well as provide a novel herbicide option for California O. sativa spontanea management. © 2022 University of California, Davis. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Application of potassium humate to reduce arsenic bioavailability and toxicity in rice plants (Oryza sativa L.) during its course of germination and seedling growth

Arsenic (As), a metalloid is a class I carcinogen and is a major problem in various parts of the world. Food crops are severely affected due to As poisoning and suffer from low germination, yield and disfiguration of morphological and anatomical traits. To attenuate such adverse effects and tone down As uptake by plants, the present study attempts to explore the role of K-humate (KH) in alleviation of As toxicity in rice. KH was administered in the growth media containing 800 ppb As (III) at varying doses to observe the stress alleviating capacity of the amendment. Five treatments were investigated, viz: (a) 800 ppb As (control), (b) 800 ppb As + 25 ppm KH, (c) 800 ppb As + 50 ppm KH, (d) 800 ppb As + 75 ppm KH and (e) 800 ppb As + 100 ppm KH. The results of the amendment administration were noted at 14 days after seeding (DAS). Application of KH significantly improved germination percentage, vigour indices and chlorophyll content by reducing the oxidative stress, antioxidant and antioxidant enzyme activities under As stress. In vivo detection of reactive oxygen species (ROS) using DCF-2DA fluorescent dye and scanning electron microscope (SEM) study of root further depicted that KH application effectively reduced ROS formation and improved root anatomical structure under As stress, respectively. Gradually increasing concentrations of KH was capable of decreasing the bioavailability of As to the rice plants, thus minimizing toxic effect of the metalloid.

Impact of organic methods of nutrient and weed management on weeds nutrient uptake and maize productivity in sandy loam soils of Rajasthan, India

An experiment was conducted during rainy (Kharif) season 2019 and 2020 at Instructional Farm, College of Agriculture, Sumerpur, Rajasthan to study the influence of organic methods of nutrient and weed management on weeds growth and nutrient uptake and maize (Zea mays L.) productivity. The experiment comprised of six weed management and five nutrient management treatments arranged in split-plot design with three replications. The stale seedbed + hoeing with power weeder at 20 days after seeding (DAS) + hoeing once at 40 DAS and stale seedbed + hoeing once at 20 DAS + application of 5 t/ha of straw mulch applied at 30 DAS recorded significantly lowest mean weed biomass at 30 DAS and at 50 DAS, respectively. They were found on par with weed free check at harvest in respect of recording mean minimum weed biomass and nutrient uptake by different categories of weeds, higher maize and nutrient uptake by maize on pooled basis. Amongst nutrient management treatments, mean minimum weed biomass and nutrient uptake, significantly higher maize yield, protein content, nutrient content and uptake by the maize was recorded with 75% recommended dose of nitrogen (RDN) using vermicompost (75% as basal + 25% as top dress at 30 DAS) + seed treatment with beejamurt + spray of 500 l/ha of jeevamurt twice (at sowing and 30 DAS). The similar trend was recorded in terms of yield and economics of maize. Next best was 75% RDN through vermicompost as basal + seed treatment with beejamurt + spray of 500 l/ha jeevamurt twice (at sowing and 30 DAS). The organic nutrient management treatments significantly increased the nutrient content in maize grain and stover, while weed management treatments have no significant effect.

Effect of crop establishment and weed management methods on weed dynamics and productivity of direct-seeded rice in middle Indo-Gangetic Plains

A field experiment was conducted during rainy seasons of 2018 and 2019 at the ICAR-Research Complex for Eastern Region Patna, Bihar to evaluate the effect of crop establishment methods and weed management treatments on weeds and productivity of direct-seeded rice (DSR). The treatments consisted of three upland DSR establishment methods, viz. zerotill direct-seeded rice:(ZT-DSR); conventional-till (CT)-dry DSR (CTDSR) and CTDSR-dust mulching, and three weed pressure maintenance treatments including: low weed pressure: maintained with pre-emergence (PE) application of pendimethalin (1.0 kg/ha) at 2 days after seeding (DAS) followed by (fb) post-emergence (PoE) application of bispyribac–Na (30 g/ha) PoE at 20 DAS fb hand weeding (HW) twice at 30 and 50 DAS; medium weed pressure: maintained with pendimethalin (1.0 kg/ha) PE at 2 DAS fb bispyribac–Na (30 g/ha) PoE at 20 DAS, and high weed pressure: maintained with pendimethalin (1.0 kg/ha) PE alone, in upland DSR under the middle Indo-Gangetic Plains (MIGPs). The major weeds recorded with upland DSR were Cyperus rotundus, Cynodon dactylon, Echinochloa colona, Brachiaria ramosa, Caesulia axillaris and Physalis minima. Significantly the lowest relative weed abundance, weed density and biomass were recorded in CT-DSR-dust mulching compared to ZT-DSR and CTDSR. Among the weed management treatment, maximum weed suppression was recorded in low weed pressure in comparison to medium and high-weed pressure management practices. Significantly higher grain yield (2.14 t/ha) and net returns (₹ 20869/ha) were obtained with CT-DSR-dust mulching. Hence, it may be concluded that for better rice productivity and weed management in upland DSR, CT-DSR-dust mulching with low weed pressure maintenance is the most potential and viable practices under the MIGPs.

Efficacy of sequential application of pre- and post-emergence herbicides for weed management in sesame

A field experiment was conducted during rainy (Kharif) seasons of 2019 and 2020 to assess the efficacy of the sequential application of pre- and post-emergence herbicides for managing complex weed flora in line sown sesame (Sesamum indicum L.) at Agriculture Research Sub-Station, Sumerpur, Pali. There were nine weed control treatments replicated thrice in a randomized complete block design. Hand weeding twice recorded the highest values of growth parameters and seed yield (1.25 t/ha) which was at par with pre-emergence application (PE) of pendimethalin 750 g/ha followed by (fb) quizalofop-p-ethyl 40 g/ha at 20 days after seeding (DAS). The uncontrolled weeds in weedy check caused 50% sesame seed yield reduction. The post-emergence application (PoE) of quizalofop-p-ethyl 40 g/ha at 20 DAS and sequential application of pre-emergence application (PE) of pendimethalin 750 g/ha PE followed by (fb) quizalofop-p-ethyl 40 g/ha at 20 DAS recorded the highest weed control efficiency, sesame seed yield, net return and benefit cost ratio and were observed to be superior than the recommended practice of pendimethalin 1000 g/ha PE fb hand weeding at 25 DAS.

Effect of different pre- and post-emergence herbicides for weed management in chickpea

A field experiment was conducted during the winter (Rabi) season 2017-18 at Instructional Agronomy Farm of Rajasthan College of Agriculture, MPUAT, Udaipur. The experiment consisted of twelve weed management treatments which were replicated thrice in Randomize Block Design. Chickpea (cv. Pratap Chana-1) was used as a test crop. The hand weeding twice 30 and 60 days after seeding (DAS) followed by pre-emergence application (PE) of pendimethalin 1000 g/ha or pendimethalin 750 g/ha have significantly reduced total weed density and biomass and attained the highest chickpea seed yield. The net return and B:C ratio was significantly higher with pendimethalin 1000 g/ha PE and pendimethalin 750 g/ha PE due to lesser cost of herbicides usage compared to hand weeding.

Bio-efficacy of nicosulfuron against mixed weed flora in maize and its residual effect on succeeding crops

A field study was conducted during Spring and rainy (Kharif) season of 2017 at N.E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar U.S. Nagar, Uttarakhand, India to evaluate the effective dose of nicosulfuron for weed control in maize while assessing its effect on growth and yield of maize along with its residual effect on succeeding pea and cowpea fodder. Eight treatments were tested which include: post-emergence application (PoE) of nicosulfuron at different doses (30, 36, 42 and 50 g/ha), tembotrione 120 g/ha PoE, pre-emergence application (PE) of atrazine 1000 g/ha, hand weeding twice at 20 and 40 days after seeding (DAS) and weedy check. The weed community during both the seasons in the experimental area consisted of, grassy weeds: Phalaris minor, Eleusine indica, Digitaria sanguinalis, Echinochloa colona and Panicum maximum, broad-leaved weeds (BLW): Trianthema monogyna, Chenopodium album, Phyllanthus niruri, Parthenium hysterophorus and Mallugo stricta and a sedge Cyperus rotundus. Nicosulfuron at 50 g/ha resulted in 50-100% weed control, depending on the weed species. Nicosulfuron at 50 and 42 g/ha were equally effective in increasing grain yield of maize when compared with tembotrione and was found superior over atrazine during both the season. No phytotoxic symptoms on maize and no residual effect on succeeding pea and cowpea fodder crop were observed, at any doses of nicosulfuron. Hence, nicosulfuron at 42 g/ha PoE may be safely used for effective weed management and improved yield of maize.

Integration effect of drip irrigation and mulching on weeds and spring maize productivity

A field experiment was carried out at Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana during spring season of 2020 and 2021. The experimental design was split-plot with three replications. The main plots included the combination of two methods of drip irrigation, viz. surface drip irrigation (SD) and sub-surface drip irrigation (SSD) and three mulch treatments, viz. plastic mulch (PM), straw mulch 6 t/ha (SM) and no mulch (NM) along with furrow irrigation (FI) as a control treatment. The sub-plots consisted of four weed control treatments, viz. pre- emergence application (PE) of atrazine 1000 g/ha, hand weeding twice at 30 and 60 days after seeding (DAS), weed free and weedy check. The dominant weed species were Cyperus rotundus, Oenothera laciniata, Chenopodium album, Coronopus didymus, Rumex dentatus, Digitaria sanguinalis, and Dactyloctenium aegyptium. The maize emergence was 6 days earlier under plastic mulch than the crop under straw mulch. The SD-PM, SD-SM, SSD-PM, SSD-SM and SSD- NM resulted in maximum maize plant height when compared to FI. SD-PM, SD-SM, SSD-PM and SSD-SM treatments recorded significantly lower total weed density and biomass at 30 DAS than the atrazine treated FI treatment. Maximum weed control efficiency of 88.89% was recorded under integration of drip irrigation with plastic mulch. Integration of drip irrigation and mulches resulted in significantly increased maize grain yield as compared to FI. Crop raised under SD- SM treatment resulted in 20.62% higher grain yield than FI. The integration of drip irrigation with mulching resulted in effective weed management and higher maize grain yield than furrow irrigation method.

Effect of herbicide mixtures on weeds and yield of summer groundnut

Field experiment was carried during summer 2020 at Agronomy farm, B. A. College of Agriculture, Anand Agricultural University, Anand, Gujarat on loamy sand soil to study the effect of herbicide mixtures on weeds and yield of summer groundnut (Arachis hypogaea L.). The experiment was conducted in randomized block design with twelve treatments, replicated four times. Weed density decreased significantly with pre-emergence application (PE) of pendimethalin + oxyfluorfen (tank mix) 900 + 120 g/ha and intercultivation (IC) followed by (fb) hand weeding (HW) at 20 and 50 days after seeding (DAS), as compared to other treatments, which resulted in significant increase in growth and yield attributes viz., periodical plant height (cm), plant dry biomass (g/plant), nodule dry weight (mg/plant), number of pods/ plant, pod yield (kg/ha), haulm yield (kg/ha), seed index (g), harvest index (%) and shelling percentage (%). Maximum net returns (Rs. 125485/ha) and B:C (4.94) was achieved with pendimethalin + oxyfluorfen 900 + 120 g/ha PE which was closely followed by IC fb HW at 20 and 50 DAS and early post-emergence application of fluazifop-p-butyl (11.1%) + fomesafen (11.1%) SL (pre-mix) 250 g/ha.

Effect of herbicides on complex weed flora and yield of summer greengram

To study the effect of a few herbicides on weed dynamics and yield of summer greengram (Vigna radiata L.), a field experiment was conducted on loamy sand soil during summer season of 2020. Digitaria sanguinalis, Cynodon dactylon, Eleusine indica and Dactyloctenium aegyptium among monocot and Digera arvensis, Portulaca oleracea, Trianthema monogyna and Phyllanthus niruri, the dicot weeds were dominant in experimental field. The pre-emergence application (PE) of either pendimethalin 750 g/ha or pendimethalin + imazethapyr (pre-mix) 750 g/ha or oxyfluorfen 117.5 g/ha PE or inter-cultivation twice and hand weeding twice at 20 and 40 days after seeding (DAS) significantly reduced the density and biomass of monocot and dicot weeds in summer greengram. These treatments recorded higher greengram growth, yield attributes, viz. plant height plant dry biomass, nodule dry weight, number of pods/plant, seed yield and benefit cost ratio (B:C).

Weed management in chickpea at South Saurashtra of Gujarat, India

A field experiment was conducted during winter (Rabi) season of 2019-20 at Instructional Farm, Department of Agronomy, College of Agriculture, JAU, Junagadh, Gujarat, India, to study the effect of different weed management treatments on weeds, yield attributes and yield of chickpea. The experiment comprised of twelve treatments laid out in randomized block design with three replications. Significantly higher plant height, number of branches / plant, number of pods/plant, seed yield and stover yield, were recorded with pre-emergence application (PE) of pendimethalin 900 g/ha followed by (fb) post-emergence application (PoE) of sodium-acifluorfen + clodinafop-propargyl 80 + 165 g/ha ready-mix (RM) at 40 DAS and hand weeding (HW) twice at 20 and 40 days after seeding (DAS) as they effectively minimized the weed biomass and lowered weed index with higher weed control efficiency. The highest net return and B:C ratio were recorded with pendimethalin 900 g/ha PE fb sodium-acifluorfen + clodinafop-propargyl 80 + 165 g/ha (RM) PoE at 40 DAS followed by alachlor 750 g/ha PE fb sodium-acifluorfen + clodinafop-propargyl 80 +165 g/ha (RM) PoE at 40 DAS and HW twice at 20 and 40 DAS.

Light quality and dormancy overcoming in seed germination of Echium plantagineum L. (Boraginaceae).

Light is considered a factor that influences the seed germination of many weed species, and it can signal whether the environmental conditions are favorable or are not favorable for germination. We aimed to study if there is an influence of light quality and dormancy overcoming in seed germination of Echium plantagineum L. We carried out a 2 x 6 factorial experiment, with and without dormancy overcoming with potassium nitrate followed by immersion in gibberellic acid; six light qualities, obtained through the light filters: blue, green, red, far-red, white light and absence of light. The evaluations performed were germination speed index (GSI), average germination time (AGT), germination at the four and 14 days after seeding (DAS), accumulated germination and relative frequency of germination. We observed significant interaction among the light qualities and seed dormancy overcoming or not for the studied variables. There was no significant effect of light qualities, in the evaluated variables, when performing dormancy overcoming, presenting germination above 90% in all the light qualities. However, without dormancy overcoming, we observed greater GSI, germination at four and 14 DAS for the red light filter with 5, 4, 29 and 45%, respectively. When the seeds were submitted to the absence of light, and without dormancy overcoming, there was only 7% of germination at 14 DAS. The seeds of E. plantagineum presented greater germination under incidence of red light, without dormancy overcoming, being classified as preferably positively photoblastics, provided that the dormancy is not overcome.

Fixed-time corrective dose fertilizer nitrogen management in wheat using atLeaf meter and leaf colour chart

AbstractFertilizer nitrogen (N) management in any region following standard general recommendations discount the fact that crop response to N varies between sites and seasons. To devise field-specific N management in wheat at jointing stage (Feekes 6 growth stage) using atLeaf meter and leaf colour chart (LCC), eight field experiments were conducted in three wheat seasons during 2017–2020 in the West Delta of Egypt. In the first two seasons, four experiments consisted of treatments with a range of fertilizer N application levels from 0 to 320 kg N ha−1. Monitoring atLeaf and LCC measurements at Feekes 6 growth stage in plots with different yield potentials allowed formulation of different criteria to apply field-specific and crop need-based fertilizer N doses. In the four experiments conducted in the third season in 2019/20, different field-specific N management strategies formulated in 2017/18 and 2018/19 wheat seasons were evaluated. In the atLeaf-based fertilizer N management experiment, prescriptive application of 40 kg N ha−1 at 10 days after seeding (DAS) and 60 kg N ha−1 at 30 DAS followed by application of an adjustable dose at Feekes 6 stage computed by multiplying the difference of atLeaf measurements of the test plot and the N-sufficient plot with 42.25 (as derived from the functional model developed in this study), resulted in grain yield similar or higher to that obtained by following the standard treatment. The LCC-based strategy to apply field-specific fertilizer N at Feekes 6 stage consisted of applying 150, 100 or 0 kg N ha−1 based on LCC shade equal to or less than 4, between 4 and 5 or equal to or more than 5, respectively. Both atLeaf- and LCC-based fertilizer N management strategies not only recorded the highest grain yield levels but also resulted in higher use efficiency with 57–60 kg N ha−1 in average less fertilizer use than the standard treatment.

Rice seed (IR64) priming with potassium humate for improvement of seed germination, seedling growth and antioxidant defense system under arsenic stress

The intolerable levels of arsenic (As) in groundwater and its application in rice cultivation are continuously affecting the rice production in Ganga-Meghna-Brahmaputra (GMB) plain. The reduced germination and plant growth rates under excessive As stress ultimately lead to lower yield. To mitigate this concerning issue, the present study was carried out to evaluate the potential of K-humate priming on seed germination and plant growth under As stress. Seeds were primed with 100 mg/l K-humate for 12 h prior to germination. The germination percentages in unprimed seeds were 65 ± 5.0% and 58.3 ± 7.6% under stress level of 50 μM AsV and 50 μM AsIII, respectively. However, germination percentage in K-humate primed seeds were 75 ± 5.0% and 68.3 ± 2.9% under AsV and AsIII stress, respectively. The vigour index I (VG I) and vigour index II (VG II) recorded on 12 DAS (days after seeding) were also increased by 1.47 and 1.51 fold, respectively with K-humate supplementation under As stress. Detrimental effects of AsIII on seed germination, seedling growth and other physiological parameters were more suppressive than AsV. Application of K-humate not only improved seed germination, seedling growth and nutrient uptake but also decreased the oxidative stress markers and antioxidant activities by minimizing As uptake and translocation in the seedlings.

Weeds and phosphorus management effect on groundnut productivity, oil content and nutrient uptake

The present study was conducted at MPUAT, Udaipur, India, during two consecutive Kharif (rainy season) of 2016 and 2017 to assess the effect of weed management treatments and phosphorus levels on weeds; groundnut growth, yield, quality and probability of groundnut cultivation. A split-plot design was used with six weed management treatments i.e., weedy check, weed free up to 60 days after seeding (DAS), pendimethalin 750 g/ha pre-emergence application (PE), oxyfluorfen 125 g/ha PE, imazethapyr 100 g/ha post-mergence application at 15 DAS (PoE) and quizalofop-ethyl 50 g/ha PoE at 15 DAS as main plots, and five phosphorus levels, viz. 0, 20, 40,60 and 80 kg P/ha as sub-plots with three replications. The lowest density of Cyperus rotundus and Echinochloa colona was recorded with imazethapyr and quizalofop-ethyl, respectively. The lowest density of other narrow-leaved weeds at 30, 60 DAS and harvest was registered with pendimethalin, quizalofop-ethyl and imazethapyr, respectively. Weed free up to 60 DAS was the most effective in managing weeds and increasing groundnut yield. Amongst herbicide treatments, imazethapyr 100 g/ha PoE recorded significantly minimum weed index, weed persistence index, crop resistance index, and the highest values of growth and yield parameters, and N, P and K uptake. Application of 60 kg P/ha has registered significantly the highest plant height, dry matter accumulation, 100 kernels weight and pod yield (1.76 t/ha), biological yield (4.86 t/ha) and also the harvest index (35.83%). Significantly higher protein and oil content were noticed when the crop was fertilized with 40 kg P/ha. The total N, P and K uptake by crop were significantly higher by 87.83, 92.10 and 60.97% over control, respectively with 80 kg P/ha.