Agronomy Journal最新文献

{"title":"Reference evapotranspiration prediction using machine learning models: An empirical study from minimal climate data","authors":"Shaloo,&nbsp;Bipin Kumar,&nbsp;Himani Bisht,&nbsp;Jitendra Rajput,&nbsp;Anil Kumar Mishra,&nbsp;Kiran Kumara TM,&nbsp;Pothula Srinivasa Brahmanand","doi":"10.1002/agj2.21504","DOIUrl":"10.1002/agj2.21504","url":null,"abstract":"<p>The scarcity of climatic data is the biggest challenge for developing countries, and the development of models for reference evapotranspiration (ET₀) estimation with limited datasets is crucial. Therefore, the current investigation assessed the efficacy of four machine learning (ML) models, namely, linear regression (LR), support vector machine (SVM), random forest (RF), and neural networks (NN), to predict ET₀ based on minimal climate data in comparison with the standard FAO-56 Penman-Monteith (PM) method. The data on daily climate parameters were collected for the period 2000−2021, including maximum and minimum temperatures (<i>T</i>_max and <i>T</i>_min), mean relative humidity (<i>R</i>_H), wind speed (<i>W</i>_S), and sunshine hours (<i>S</i>_SH). The performance of the developed models considering different input combinations was evaluated by using several statistical performance measures. The results showed that the SVM model performed better than the other ML models during training (<i>R</i>² = 0.985; mean absolute error [MAE] = 0.170 mm/day; mean square error [MSE] = 0.052 mm/day; root mean square error [RMSE] = 0.229 mm/day; mean absolute percentage error [MAPE] = 5.72%) and testing stages (<i>R</i>² = 0.985; MAE = 0.168 mm/day; MSE = 0.050 mm/day; RMSE = 0.224 mm/day; MAPE = 5.91%) under full dataset scenario. The best performance of the models to estimate was with <i>T</i>_max, <i>R</i>_H, <i>W</i>_s, <i>S</i>_SH, and <i>T</i>_min. The results of the current study are substantial as it offers an approach to estimate ET₀ in semi-arid data-scarce region.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 3","pages":"956-972"},"PeriodicalIF":2.1,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135091599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dodine as an alternative to chlorothalonil in the control of leaf spot diseases in peanut","authors":"Chiara Rossi,&nbsp;Albert K. Culbreath,&nbsp;Timothy B. Brenneman,&nbsp;Ronald Scott Tubbs,&nbsp;Daniel J. Anco,&nbsp;George Vellidis,&nbsp;Cristiane Pilon","doi":"10.1002/agj2.21508","DOIUrl":"10.1002/agj2.21508","url":null,"abstract":"<p>Peanut (<i>Arachis hypogaea</i> L.) is susceptible to leaf spot diseases caused by the fungi <i>Nothopassalora personata</i> and <i>Passalora arachidicola</i>, which can decrease yield substantially. Chlorothalonil is one of the most widely used fungicides to control these diseases but was recently banned in the European Union due to toxicity to amphibians and fish. Dodine is an alternative fungicide with a similar range of activity. However, information about its impact on the peanut physiology is lacking. The objectives of this study were to assess the effect of dodine on leaf photosynthesis, yield, and pod quality of peanut and evaluate the potential of dodine as a replacement of chlorothalonil in the control of leaf spot diseases. A 3-year field experiment was conducted using Georgia-06G. Treatments consisted of chlorothalonil at 0.86 kg a.i. ha⁻¹ (high rate), chlorothalonil at 0.43 kg a.i. ha⁻¹ (low rate), dodine at 0.68 kg a.i. ha⁻¹ (high rate), and dodine at 0.34 kg a.i. ha⁻¹ (low rate). Photosynthetic efficiency was altered by fungicide in only a few instances, and a clear trend was not observed. The high rate of dodine resulted in the least defoliation caused by leaf spot of all fungicide treatments. Pod maturity, yield, and grading parameters were not affected by fungicide. Overall, dodine did not impact negatively the photosynthetic activity, pod quality, and yield of peanut. Moreover, this chemistry was efficient in controlling leaf spot diseases under heavy disease pressure; therefore, dodine is a potential replacement of chlorothalonil in the control of leaf spot diseases in peanut.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 1","pages":"202-216"},"PeriodicalIF":2.1,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/agj2.21508","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135590233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Information conveyed by management zones and optimal soybean seeding rate","authors":"Yue Zhao,&nbsp;David A. Hennessy,&nbsp;Laura E. Lindsey,&nbsp;Maninder P. Singh,&nbsp;Alexander J. Lindsey","doi":"10.1002/agj2.21509","DOIUrl":"10.1002/agj2.21509","url":null,"abstract":"<p>The application of variable rate seeding (VRS) enables soybean [<i>Glycine max</i> (L.) Merr.] growers to allocate seed more efficiently on heterogeneous farmland and thus potentially increases profit by reducing seed cost and/or increasing yield. Successful implementation of VRS depends on the appropriate division of management zones where producers apply different seeding rates. We construct an economic conceptual model for evaluating the information conveyed by management zones. The model implies that distinct management zones should differ by marginal seed productivity when evaluated at the same seeding rate. Based on this model and a dataset collected from 10 on-farm trials in Ohio and Michigan in 2017 and 2018, we implement a quadratic model regression analysis describing yield response to seeding rate. Results show that management zones in four out of 10 trials do not display statistically significant differences in marginal seed productivity. The small differences across management zones could result from the soybean plant's ability to compensate for yield due to fewer plants by increasing branches per plant and/or from inappropriately identified management zones. The estimated profit gains from applying VRS across the 10 trials vary from $0.20 to $30.60 ha⁻¹. We also find that increasing seeding rate and mean yield decreases yield variability and yield skewness. Overall, the difference in marginal seed productivity is crucial for the appropriate determination of VRS management zones.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 1","pages":"289-301"},"PeriodicalIF":2.1,"publicationDate":"2023-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/agj2.21509","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135724765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parental selection proposal strategy for recurrent selection in tropical wheat breeding","authors":"Victor Silva Signorini,&nbsp;Caique Machado e Silva,&nbsp;Gabriel Wolter Lima,&nbsp;Eduardo Filipe Torres Vieira,&nbsp;Henrique Caletti Mezzomo,&nbsp;Cleiton Renato Casagrande,&nbsp;Maicon Nardino","doi":"10.1002/agj2.21505","DOIUrl":"10.1002/agj2.21505","url":null,"abstract":"<p>Recurrent selection is an effective breeding method for improving complex traits in wheat (<i>Triticum aestivum</i> L.) breeding. In this study, we propose a genitor selection strategy, employing a multi-trait selection approach and genetic diversity analysis. To evaluate our proposed method, we conducted a lattice design trial during the winter seasons of 2020 and 2021 in Viçosa, MG, Brazil, comprising 87 lines and 13 commercial cultivars. It assessed various traits such as plant height, days to heading, wheat leaf rust, tan spot of wheat, a hundred grain mass, hectoliter weight, and grain yield, and the best linear unbiased predictor (BLUP) was obtained for each trait via restricted maximum likelihood. Next, a genotypic distance matrix, derived from principal component analysis using the BLUP values, was computed to perform hierarchical clustering via the unweighted pair group method with arithmetic mean. The selection of superior genotypes was made utilizing the multi-trait genotype-ideotype distance index, resulting in the identification of eight lines and two commercial cultivars as candidates. Furthermore, the genetic diversity analysis revealed distinct clusters among the selected genotypes. To assess the divergence of the chosen genitors, this study proposes a complementarity matrix using factor analysis. Our results indicate that this selection strategy effectively directed the identification of the best and divergent genitors. The complementarity matrix developed in this paper to evaluate the crossings proposal can also be used to evaluate combinations in any panel selected via a multi-trait approach and can be easily applied and interpreted by breeders of various programs.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 1","pages":"36-50"},"PeriodicalIF":2.1,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135818380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physiological components of seed quality in runner-type peanut during seed formation","authors":"Leticia Moreno,&nbsp;Adão F. Santos,&nbsp;Ronald Scott Tubbs,&nbsp;Timothy L. Grey,&nbsp;Walter S. Monfort,&nbsp;Marshall C. Lamb,&nbsp;Cristiane Pilon","doi":"10.1002/agj2.21506","DOIUrl":"10.1002/agj2.21506","url":null,"abstract":"<p>Seed is one of the most expensive costs in peanut (<i>Arachis hypogaea</i> L.) production, and the use of high-quality seed is important to provide the greatest yield potential. Physiological seed quality, represented by a combination of germination, vigor, desiccation tolerance, and longevity, is progressively acquired during seed formation. When all components reach their maximum, seeds achieve the highest physiological quality. The objectives of this study were to identify the acquisition pattern of the physiological components of seed quality, to determine the timing in which the maximum physiological quality is achieved during seed formation, and to define the timing in which seeds acquire and further break primary dormancy in peanut. A 3-year field study was conducted using the cultivar Georgia-06G. Plants were inverted when growing degree days reached 2500 for all fields, and a maturity board profile was used to classify the pods into the maturity classes. Seeds were split into two groups, treated and non-treated, with ethephon to break potential primary dormancy. Water content, germination, vigor, desiccation tolerance, and longevity were tested in the seeds. Seed mass maturity was reached in the “orange” class. Maximum germination and vigor were achieved between “brown 1” and “brown 2”. Primary dormancy was acquired between “orange” and “brown 1” and broken after artificial drying. Maximum desiccation tolerance was observed in “brown 1”, whereas maximum longevity was achieved only in “black 2”. Considering all physiological quality components, peanut seeds achieved the maximum physiological quality between “brown 1” and “brown 2”.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 1","pages":"189-201"},"PeriodicalIF":2.1,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/agj2.21506","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135867951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparison of transient elastography with acoustic radiation force impulse elastography for the assessment of liver health in patients with chronic hepatitis C: Baseline results from the TRACER study.","authors":"Therese Herlihy, Mary Moran, Aoife Heeney, Hajra Okhai, Davide De Franceso, Carmel Cronin, Eoin Feeney, Diarmuid Houlihan, Stephen Stewart, Aoife G Cotter","doi":"10.1177/1742271X221139181","DOIUrl":"10.1177/1742271X221139181","url":null,"abstract":"<p><strong>Background: </strong>Liver stiffness measurements can be used to assess liver fibrosis and can be acquired by transient elastography using FibroScan^® and with Acoustic Radiation Force Impulse imaging. The study aimed to establish liver stiffness measurement scores using FibroScan^® and Acoustic Radiation Force Impulse in a chronic hepatitis C cohort and to explore the correlation and agreement between the scores and the factors influencing agreement.</p><p><strong>Methods: </strong>Patients had liver stiffness measurements acquired with FibroScan® (right lobe of liver) and Acoustic Radiation Force Impulse (right and left lobe of liver). We used Spearman's correlation to explore the relationship between FibroScan® and Acoustic Radiation Force Impulse scores. A Bland-Altman plot was used to evaluate bias between the mean percentage differences of FibroScan® and Acoustic Radiation Force Impulse scores. Univariable and multivariable analyses were used to assess how factors such as body mass index, age and gender influenced the agreement between liver stiffness measurements.</p><p><strong>Results: </strong>Bland-Altman showed the average (95% CI) percentage difference between FibroScan® and Acoustic Radiation Force Impulse scores was 27.5% (17.8, 37.2), <i>p</i>  < 0.001. There was a negative correlation between the average and percentage difference of the FibroScan^® and Acoustic Radiation Force Impulse scores ( <i>r</i> (95% CI) = -0.41 (-0.57, -0.21), <i>p</i> < 0.001), thus showing that percentage difference gets smaller for greater FibroScan^® and Acoustic Radiation Force Impulse scores. Body mass index was the biggest influencing factor on differences between FibroScan^® and Acoustic Radiation Force Impulse (<i>r</i> = 0.12 (0.01, 0.23), <i>p</i> = 0.05). Acoustic Radiation Force Impulse scores at segment 5/8 and the left lobe showed good correlation (<i>r</i> (95% CI) = 0.83 (0.75, 0.89), <i>p</i> < 0.001).</p><p><strong>Conclusion: </strong>FibroScan^® and Acoustic Radiation Force Impulse had similar predictive values for the assessment of liver stiffness in patients with chronic hepatitis C infection; however, the level of agreement varied across lower and higher scores.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"77 1","pages":"244-253"},"PeriodicalIF":4.4,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10621485/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89831200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inoculant and fertilizer effects on lentil in the US northern Great Plains","authors":"P. R. Miller,&nbsp;S. C. Atencio,&nbsp;C. A. Jones,&nbsp;P. M. Carr,&nbsp;E. Eriksmoen,&nbsp;W. Franck,&nbsp;J. Rickertsen,&nbsp;S. I. Fordyce,&nbsp;M. Ostlie,&nbsp;P. F. Lamb,&nbsp;D. L. Fonseka,&nbsp;M. A. Grusak,&nbsp;C. Chen,&nbsp;M. Bourgault,&nbsp;S. T. Koeshall,&nbsp;K. W. Baber","doi":"10.1002/agj2.21501","DOIUrl":"10.1002/agj2.21501","url":null,"abstract":"<p>Lentil (<i>Lens culinaris</i> Medikus) is an important crop, averaging over 250,000 ha in Montana and North Dakota during 2016–2021. However, relatively little is known about rhizobial inoculant and fertility response in lentil in the US northern Great Plains. The objective was to evaluate the effect of rhizobial inoculant formulations (seed coat and in-furrow) and nutrient additions (potassium [K], sulfur [S], and micronutrients) on lentil yield and seed protein concentration. This study was conducted at seven university research centers in Montana and North Dakota from 2019 to 2021, resulting in 20 location-years of data. In six of 20 experiments, inoculant application increased seed yield by an average of 36% (323 kg ha⁻¹, <i>p</i> ≤ 0.05) but had no consistent effect on seed protein concentration. Lentil or pea crop history among locations did not explain inoculant response. Inoculant formulations (seed coat vs. in-furrow) and K fertilizer had inconsistent and small effects on seed yield and protein concentration. However, S fertilizer (5.6 kg S ha⁻¹) increased seed yield in four of 20 experiments (<i>p</i> ≤ 0.02) by an average of 14.5% (255 kg ha⁻¹) in those experiments and decreased seed yield for one experiment (<i>p</i> = 0.05) by 5.8% (153 kg ha⁻¹). Pre-plant SO₄-S soil test levels did not predict lentil response to S fertilizer. Micronutrient application was assessed in 12 location-years but had no effect on lentil yield or protein concentration. This research suggests a need to better understand what factors control lentil yield and protein response to rhizobial inoculant and S fertilization.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 2","pages":"704-718"},"PeriodicalIF":2.1,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/agj2.21501","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cover crops impact phosphorus cycling and environmental efficiency in a corn–soybean system","authors":"Megan A. Bourns,&nbsp;Nathan O. Nelson,&nbsp;R. Elliott Carver,&nbsp;Kraig L. Roozeboom,&nbsp;Gerard J. Kluitenberg,&nbsp;Peter J. Tomlinson,&nbsp;Qing Kang,&nbsp;Ganga M. Hettiarachchi","doi":"10.1002/agj2.21498","DOIUrl":"10.1002/agj2.21498","url":null,"abstract":"<p>Solutions to simultaneously meet crop phosphorus (P) demand and reduce P loss from agricultural systems are required to improve the sustainability of our production. Our objective was to determine the effect of cover crop addition (with cover crop [CC], and without cover crop [NC]) and P fertilizer management (zero P control [CN], fall broadcast [FB], and spring injected [SI]) on P cycling, agronomic P use efficiency (PUE), and environmental P use efficiency (EPUE), measured as the percent of P lost in runoff water, in a no-till corn (<i>Zea mays</i>)–soybean [<i>Glycine max</i> (L.) Merr.] rotation. The experiment was a 2 × 3 factorial. Both FB and SI increased P cycling through the main crop and cover crop tissue, compared to the CN. Cover crop did not affect main crop P uptake, removal in grain, or return to soil in crop residue, but CC treatment increased total P uptake and return in the system. Cover crop effects on P uptake, removal, and return were the same regardless of P fertilization treatments. Phosphorus fertilizer and CC treatments did not affect PUE. Both FB and SI P fertilizer management decreased EPUE, although SI tended to decrease EPUE less than FB. Cover crop significantly improved EPUE only in 2019, when CC reduced erosion losses. Therefore, cover crops were not consistently beneficial for reducing the environmental effects of P fertilization, and their use cannot replace the importance of sound P fertilizer stewardship, including sub-surface P placement. However, cover crops play an important role in improving EPUE in years with high erosion loss potential.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 1","pages":"109-120"},"PeriodicalIF":2.1,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/agj2.21498","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136376356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Critical levels and nitrogen fertilizer equivalencies for grain protein in winter wheat","authors":"Dan S. Long,&nbsp;Catherine L. Reardon,&nbsp;Curtis B. Adams","doi":"10.1002/agj2.21499","DOIUrl":"10.1002/agj2.21499","url":null,"abstract":"<p>Precision nitrogen (N) application methods have been developed for dryland wheat that utilize site-specific measurements of grain protein concentration (GPC) to determine N fertilizer recommendations for the next season. The objectives of this study were to determine the critical protein level and N equivalent to a unit change in GPC from relationships between GPC, and grain yield or plant-available N in soft white winter wheat (SWW, <i>Triticum aestivum</i> L.), and assess the consistency of these relationships across SWW cultivars grown under a wide range of precipitation. A 3-year study was undertaken near two sites: Lexington (225 mm of mean annual precipitation) and Adams (450 mm) in Oregon. Differences in precipitation and N fertilization rates between sites were used to induce variability in grain yield and GPC of four cultivars. A critical protein concentration of 117.5 g kg⁻¹ was defined by Cate–Nelson analysis of scatter plots of relative yield versus GPC. Critical protein among cultivars ranged between 105 and 118 g kg⁻¹ suggesting that 117.5 g kg⁻¹ might be used as a general indicator of N sufficiency. Slopes of the regression of available N on GPC were consistent across cultivars and revealed that 4.2–8.4 kg N ha⁻¹ is equivalent to a unit change protein (1 g kg⁻¹) in lower precipitation areas of the region where SWW is under water stress during grain filling. This information is useful in calculating the N to apply from the GPC in the previous season to meet crop requirements in the next season.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 1","pages":"339-348"},"PeriodicalIF":2.1,"publicationDate":"2023-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/agj2.21499","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135462626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing clethodim spot spraying applications for control of problematic weedy rice and other grasses in California rice fields","authors":"Rasim Unan,&nbsp;Liberty Galvin,&nbsp;Aaron Becerra-Alvarez,&nbsp;Kassim Al-Khatib","doi":"10.1002/agj2.21500","DOIUrl":"10.1002/agj2.21500","url":null,"abstract":"<p>Spot spraying applications offer the opportunity to target specific weeds in a field, while simultaneously reducing herbicide usage and increasing the long-term efficacy of chemical control options. The study is focused on controlling California weedy rice accessions (<i>Oryza</i> spp.) and problematic grass weeds with a spot spray application of clethodim in a flooded rice system. The efficacy of incorporating nonionic surfactant to clethodim applications was also assessed. Dose-response experiments were carried out in a greenhouse on five weedy rice accessions, common grass rice weeds, and cultivated rice varieties L207, M105, M206, M209, M211, and S102 to determine the dose needed to affect these populations. Clethodim was applied in a field setting to assess spot spraying efficacy, the possibility of herbicide dispersion in the water, and crop injury. Clethodim successfully controlled weedy rice and grasses in the greenhouse. The effective rates to control 90% of the five test populations (ED₉₀) were between 51 and 74 g ai ha⁻¹ clethodim for weedy rice accessions. Adding nonionic surfactant to clethodim increased its efficacy by 1.6- to 1.9-fold. Cultivated rice varieties did not exhibit any tolerance to clethodim, however, spot spraying applications at 150 g ai ha⁻¹ clethodim did not cause any dispersion in the field. Clethodim spot spray application was effective both at the three- to four-leaf growth stage and tillering growth stage for weedy rice.</p>","PeriodicalId":7522,"journal":{"name":"Agronomy Journal","volume":"116 1","pages":"302-312"},"PeriodicalIF":2.1,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135512542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}