Preplant Application Research Articles

Effect of Phosphorus Fertilization on Yield of Chipping Potato Grown on High Legacy Phosphorus Soil

Potato (Solanum tuberosum L.) has low phosphorus (P) use efficiency as compared with other vegetable crops. This study was conducted at two commercial chipping potato farms (A and B) in Northeast Florida to evaluate different P rates for potato production. Plot size was 0.62 and 0.49 hectares for Farms A and B, respectively. The total trial area was 13.32 hectares per growing season for three consecutive years from 2018 to 2020. The randomized complete block design (RCBD) was employed with four replications per P rate. The chipping potato variety, ‘Atlantic’ was cultivated with three P rates: 0, 24.5, and 48.9 kg P ha−1 in 2018, and 12.2, 24.5, and 48.9 kg P ha−1 in 2019 and 2020. The soil of Farm A contained 497 mg kg−1 Mehlich-3 extractable P and 946 mg kg−1 aluminum (Al), and that of Farm B had 220 mg kg−1 Mehlich-3 extractable P and 253 mg kg−1 Al. The results showed that a P rate of 48.9 kg P ha−1 significantly improved tuber yield as compared to 0 in 2018 or 12.2 kg P ha−1 in 2019 and 2020. Application of 48.9 kg P ha−1 fertilizer P significantly increased the soil P level in 2018 and 2020, while the application of 24.5 kg P ha−1 fertilizer P increased the soil P level significantly in 2018 only. Tubers with 48.9 kg P ha−1 showed significantly lower external quality issues than 0 or 12.2 and 24.5 kg P ha−1. However, there were no significant differences in specific gravity, internal tuber quality, and tuber size among the different P rates. The tuber yield data show that potato plants grown on soil with high legacy P still require approximately 50 kg ha−1 P application for sustainable potato production in the area. This high P requirement results from the combination of high concentrations of active metals (Al and iron (Fe)) and a decrease in pH of one unit in the growing season. New P-fertilization programs with post-plant applications rather than with pre-plant application are urgently needed for minimizing P-immobilization by Al and Fe and improving P-use efficiency for potato production in the state.

Effect of Preplant Application of Post Emergent Herbicide Glyphosate on the Events of Germination, Growth and Biochemical Composition of Blackgram Seedlings

Weed causes heavy yield loss when it competes with crops especially for light, water, nutrient and space. In crop production, weed management is a necessary operation to get a higher yield. Manual weeding operation is an easy and environmentally friendly method but it increases the cost of cultivation and makes the crop production practice a non-profitable business venture. Under this situation, the herbicide can be used as the most practical and effective alternative means of weed control. In intensive agriculture heavy use of herbicide affects the growth and biochemical composition of the crop. The objective of this study was to find out the effect of pre-plant soil application of post emergence glyphosate on the germination, growth and biochemical composition of blackgram seedlings. Results showed that glyphosate 1000 ppm did not significantly affect the germination of blackgram seeds. However, the higher concentration of 1000 ppm affects the root (1.08 cm) and shoot length (6.16 cm) compared to control (6.16 and 12.27 cm, respectively) and the lower concentration at the rate of 10 ppm enhance the root (6.26 cm) and shoot length (12.49 cm). Soluble protein content was higher in glyphosate 1000 ppm (70.60 mg g-1) compare to control (59.40 mg g-1). The finding concludes that the pre-plant application of post emergence herbicide glyphosate didn’t affect the germination. However it has reduced the root and shoot length of blackgram when applied at higher concentrations. Contrary to the higher dose the lower dose of glyphosate stimulates the growth and development of blackgram seedlings.

Maize response to coupled irrigation and nitrogen fertilization under center pivot, subsurface drip and surface (furrow) irrigation: Growth, development and productivity

Water availability and water quality problems negatively impact agricultural productivity due to improper nitrogen (N) and irrigation management, which can also negatively affect environmental services. Coupled irrigation and N management practices must be developed and practiced for alleviating these challenges. Investigating crop growth and development and yield response to coupled irrigation and N management under different irrigation methods can aid in developing optimum agronomic management practices to enhance crop production efficiency. Field experiments were conducted in 2016 and 2017 growing seasons to measure and compare maize (Zea mays L.) grain yield, leaf area index (LAI), plant height (and their relationships), and stem diameter under different N application timing treatments and traditional N application under different irrigation methods [center pivot (CP), subsurface drip irrigation (SDI), and furrow irrigation (FI)]. The irrigation levels were full irrigation treatment (FIT or 100%), 80% of FIT, 60% of FIT, and rainfed conditions (RFT) coupled with fertigation application timing treatments. The N treatments were: (i) traditional (TN) with spring pre-plant application, (ii) non-traditional-1 (NT-1) with three pre-season and in-season N applications, and (iii) non-traditional-2 (NT-2) with four pre- and in-season N applications. Grain yield, LAI, and plant height were significantly (p < 0.05) altered by increasing irrigation levels for the traditional N and non-traditional N treatments for the given irrigation method as well between the irrigation methods for the same treatment. The irrigation method had a substantial influence on LAI, and both CP and SDI had 24% higher averaged LAI than FI across traditional N treatments. The highest grain yields were observed under NT-1 and NT-2 at FIT across the irrigation methods. The highest grain yields of 17.3, 16.8 and 15.2 Mg ha-1 were observed in 100% NT-1-CP, 100%-NT-1-SDI, and 100% T-FI in the 2016 growing season, respectively; and 17.8, 16.7 and 14 Mg ha-1 were observed in 100% NT-1-CP, 100%-NT-2-SDI, and 100% T-FI in the 2017 growing season, respectively. The traditional N treatment showed significantly (p < 0.05) higher yield under CP than FI (8.1% and 25.5% higher under CP in 2016 and 2017, respectively). SDI had 8.1% and 23% higher yield than FI in 2016 and 2017 seasons, respectively. NT-1 and NT-2 treatments had significantly higher (p < 0.05) grain yields than traditional N treatment under CP and SDI; and NT-1 and NT-2 yields were significantly higher (p < 0.05) under CP than SDI. There was no significant difference (p > 0.05) in yield between NT-1 and NT-2. However, the TN-1 yielded 4.3% higher under CP than in SDI method. NT-1 can be an effective N management practice coupled with 80% of FIT irrigation level under CP and SDI. Results and analyses presented here can provide guidance to growers and their advisors to assess maize productivity under different irrigation and N management strategies under different irrigation methods in the soil, climatic and management practices similar to those presented in this research.

Improving the Level and Consistency of Glyphosate-Resistant Canada Fleabane (Erigeron canadensis L.) Control With Bromoxynil-Based Tankmixes Applied Preplant to Soybean

Glyphosate-resistant (GR) Canada fleabane (Erigeron canadensis L.) is a problematic weed in soybean. Bromoxynil-based tankmixes provide control of GR Canada fleabane in monocot crops; however, there is limited research on preplant (PP) applications in soybean. The objective of this study was to determine the best third tankmix partner with glyphosate plus bromoxynil applied PP to improve the level and consistency of GR Canada fleabane control in soybean. Four field trials were conducted over a two-year (2020, 2021) period. Glyphosate plus bromoxynil controlled GR Canada fleabane 52, 58, and 69% at 2, 4, and 8 weeks after application (WAA) respectively. The addition of saflufenacil to glyphosate plus bromoxynil improved GR Canada fleabane control 39% at 2 WAA and the addition of dicamba to glyphosate plus bromoxynil improved GR Canada fleabane control 39 and 29% at 4 and 8 WAA, respectively. The addition of bromoxynil to glyphosate plus 2,4-D ester or dicamba improved GR Canada fleabane control by 36 and 35%, respectively, at 2 WAA. The addition of bromoxynil to glyphosate plus tiafenacil or pyraflufen-ethyl/2,4-D improved GR Canada fleabane control by 19% at 8 WAA. The addition of bromoxynil to glyphosate plus metribuzin improved GR Canada fleabane control 31, 32, and 36% at 2, 4, and 8 WAA, respectively. Antagonism was observed between bromoxynil plus glyphosate plus tiafenacil or halauxifen-methyl 8 WAA, while the interaction between bromoxynil plus glyphosate plus pyraflufen-ethyl/2,4-D was considered synergistic. The addition of metribuzin, tiafenacil, pyraflufen-ethyl/2,4-D, 2,4-D ester, halauxifen-methyl, saflufenacil or dicamba to glyphosate plus bromoxynil improved the consistency of GR Canada fleabane at 2, 4, and 8 WAA. This study concludes that the addition of saflufenacil or dicamba to glyphosate plus bromoxynil can improve the level and consistency of GR Canada fleabane control applied PP to soybean.

In-season split nitrogen application and cover cropping effects on nitrous oxide emissions in rainfed maize

Cover crops and in-season nitrogen (N) management are promoted as key conservation practices for reducing nitrate leaching losses from agricultural fields. However, their combined effects on soil nitrous oxide (N2O) emissions per unit of crop productivity remains uncertain. These practices might contribute to high N2O emissions by providing N and C substrates for microbial denitrification activity, especially when in-season N application coincides with cover crop decomposition. The objective of this study was to evaluate the effects of N application timing and cereal rye (CR, Secale cereale L) cover crops on area- and yield-scaled soil N2O emissions in continuous maize (Zea mays L.) over 3-yr (2018–2020). Treatments were: Pre-Season-N: 224 kg N ha-1 split-applied in fall + pre-plant in 2018, or as single pre-plant applications in 2019 and 2020; In-Season-N: pre-plant + side-dress (growth stage V6-V7); In-Season-N + CR: ; and a zero N plot as the Control. We found that shifting from pre-season to in-season split N application did not significantly affect area- or yield-scaled N2O emissions in any year. Despite high N2O spikes for the In-Season-N + CR following side-dress N application in all years, this did not translate to consistently higher cumulative N2O emissions. Compared with Pre-Season-N and In-Season-N, In-Season-N + CR significantly increased area- and yield-scaled N2O emissions by approximately 50% in 1 of 3 years. These results suggest the combination of high soil N supply, warm and wet soil conditions, and cover crop decomposition contributes to elevated N2O emissions, but the cumulative effects of side-dress N application with a CR cover crop are variable across years. With increasing adoption of these practices to reduce nitrate leaching losses from croplands, future work should simultaneously assess effects on N2O emissions and crop yield to account for potential tradeoffs in N loss pathways.

Split-nitrogen application with cover cropping reduces subsurface nitrate losses while maintaining corn yields.

Artificial subsurface drainage is essential to sustain crop production in many areas but may also impair water quality by exacerbating nitrate (NO3 )-nitrogen (N) delivery downstream. Cover crops and split-N application have been promoted as key conservation practices for reducing NO3 -N losses, but few studies have simultaneously assessed their effect on water quality and crop productivity. A field study was conducted to evaluate the effects of N application timing and cover crops on subsurface drainage NO3 -N losses and grain yield in continuous corn (Zea mays L.). Treatments were preplant-N: 224kg N ha-1 split-applied with 60% fall + 40% preplant in 2018, or as single preplant applications in 2019 and 2020; split-N: 40% preplant + 60% side-dress (V6-V7); split-N + cover crop (CC): Split-N + cereal rye (Secale cereale L.); and a zero N plot as the control. Across the 3-yr study period, split-N + CC significantly reduced flow-weighted NO3 -N concentration and NO3 -N loss by 35 and 37%, respectively, compared with preplant-N. However, flow-weighted NO3 -N concentration (4.3mg L-1 ) and NO3 -N loss (22.4kg ha-1 ) with split-N were not significantly different from either preplant-N (4.8mg L-1 and 26.4kg ha-1 , respectively) or split-N + CC (3.1mg L-1 and 16.7kg ha-1 , respectively). Corn yield was significantly lower in the control treatment but did not differ among N fertilized treatments in any year. These results indicate that combining split-N application with cover crops holds promise for meeting the statewide interim milestone NO3 -N reduction target of 15% by 2025 without negatively impacting crop productivity.

Sensitivity of lettuce cultivar Lucy Brown to pre-planting herbicide application

ABSTRACT Due to the low availability of herbicide active ingredients, the chemical weed management in lettuce crop is a challenge. The aim of this study was to evaluate the sensitivity of lettuce to the pre-planting application of the herbicides flumioxazin and trifluralin alone or in tank-mixture in lettuce, Lucy Brown cultivar. Two experiments were conducted. In experiment A, the soil was tilled before the herbicide application and it was tilled again before seedling transplanting. In experiment B, the soil was tilled just once before the herbicide application. The experimental design was in randomized blocks in a factorial scheme (3x3) +1 (2 factors with 3 levels and an additional control) with 4 replicates. We applied flumioxazin (120 g ha-1), trifluralin (450 g ha-1) and flumioxazin + trifluralin (120 + 450 g ha-1) in three different seasons before transplanting (0, 7 and 14 days). Lettuce productivity after trifluralin application (48.4 t ha-1) was higher than after flumioxazin application (16.8 t ha-1) in experiment A. In experiment B, flumioxazin decreased the number of lettuce leaves (25.6) at 14 DAT; no differences in lettuce productivity were verified, though. The herbicide trifluralin caused lower levels of phytotoxicity and was the most selective between the treatments when applied in the three seasons in both experiments.

Yield and quality of strawberries when applying fertilizers

Relevance. One of the most important elements of the technology of cultivation of strawberries for increasing productivity and improving the quality of berries is the use of fertilizers that can regulate the growth, development, yield and quality of products.Methods. During 2016-2018, the impact of pre-planting application of complex mineral fertilizers on the yield and quality of strawberries in the Udmurt Republic was studied. The analysis of meteorological conditions during the growing season of the crop according to the research results is carried out.Results. The results of the use of complex fertilizers Azofoska, Perm-yagodnoye and Fusco-yagodnoye on garden strawberries when grown in the conditions of the Udmurt Republic are presented. It was found that the use of these fertilizers in comparison with the control (Azofoska) contributes to an increase in yield and has a positive effect on the quality of berries. The aftereffect of the studied fertilizers on the second and third year of fruiting of wild strawberries is noted. According to the results of research, the highest yield of berries of the garden strawberry was obtained in 2016 in the first year of fruiting when applying Chamfer-berry (1.33 kg/m2 ). The pre-planting application of the FaskoYagodnoye fertilizer provided a reliable increase in yield at all times of berry harvesting, and on average for three years by 0.13 kg/m2 with an NSR of 0.04 kg/m2 . The content of dry matter, water-soluble sugars and vitamin C in the berries corresponded to the characteristics of the Darenka variety and to a greater extent depended on the meteorological conditions of the growing season of strawberries.

Impact of Weed Management Practices on Soil Microflora and Dehydrogenase Enzyme Activity Under Varying Levels of Nitrogen in Winter Season Onion (Allium cepa L.).

The study was conducted to evaluate the suitability of different weed management practices under influence of varying levels of N doses to test their effects on the various soil microflora and dehydrogenase enzyme activity in the winter onion field during 2016-2017 and 2017-2018. There were a total of twenty eight treatments replicated three times under the split-plot design (SPD). The treatments associated with weed management practices were applied to the main plots and the different N doses were given in each subplot. Microbial population and dehydrogenase enzyme activity in soil and crop weed competition index were determined. The two-hand weeding (HW) at 20 and 40days after transplanting (DAT) of onion seedlings as well as preplant application of oxyfluorfen along with one HW at 40 DAT, exhibited a significant increase in dehydrogenase activity and microbial population in the soil when the N was applied at 100kgha-1. The study suggests that suitable weed management practices for the winter onion exerts a transient impact on soil microbial population, maintained good soil health and reduced crop-weed competition (CWC) with relatively less environmental hazards.

Сравнительная оценка комплексных удобрений при внесении под землянику садовую

Abstract. The productivity of wild strawberries is significantly determined not only by the biological characteristics of the variety and soil and climatic conditions, but also by agrotechnical techniques and the use of organomineral fertilizers. The effectiveness of the use of mineral fertilizers on strawberries has been proven by numerous studies [5, p. 48; 6, p. 99; 14, p. 233; 15, p. 513; 16, p.101; 17, p. 513]. The purpose is a comparative assessment of the effect of various types of complex fertilizers for strawberries. The task was to study the effect of complex fertilizers on the yield of strawberry and its structure. In 2015–2018, studies were conducted on the introduction of complex fertilizers for wild strawberries, which are used during the growing season to improve their nutrition during periods of maximum consumption of nutrients. Methods. The studies were conducted according to generally accepted methods [4], [7]. The influence of “Azophoska”, “Perm-yagodnoye” and “Fasko-yagodnoye” fertilizers on the yield and elements of its structure in strawberry was studied in the conducted studies. Results. The best results for all the years of research were obtained when using the pre-planting application of the fertilizer “Fasko-yagodnoye”. In this variant, there was a significant increase in the number of berries by 1.8 pcs., their weight by 0.68 g and yield by 0.13 kg/m2. Scientific novelty. For the first time in the conditions of the Udmurt Republic, the effect of the pre-planting application of complex fertilizers “Perm-yagodnoye” and “Fasko-yagodnoye” was studied on strawberry garden. Practical significance. The obtained research results are of great practical value, since it is proved that the productivity of wild strawberries in the Udmurt Republic increases with the use of complex fertilizers.

Using Analytical Techniques and Cole Crop Field Responses to Quantify 2,4-D plus Glyphosate Removal from the Surface of Plastic Mulch

Planting cole crops and leafy greens in plastic mulch free of summer and winter annual broadleaf weeds is challenging. Because these crops are often grown as a second or third crop on mulch, weeds emerge in previously punched plant holes, tears in plastic, and row middles. Without the ability to use tillage and with limited herbicide options available for weed control, achieving a weed-free planting window is not often feasible. Additional herbicide options are needed, but their interaction with plastic mulch must be understood. Therefore, research has determined the persistence of preplant applications of 2,4-D tank-mixed with glyphosate applied over plastic mulch. Analytical laboratory analyses of plastic samples from field experiments, in conjunction with bioassays using broccoli (Brassica oleracea var. botrytis L.) and collard (Brassica oleracea var. viridis L.), evaluated herbicide dissipation. Analytical studies determined that 0.5 cm of irrigation after herbicide application and 1 day before planting removed 99% of 2,4-D, and 100% of glyphosate from the plastic mulch. Waiting an additional 14 days after application and irrigation further reduced the amount of 2,4-D on the plastic mulch 88% to 95%. For the field bioassay, preplant applications of 2,4-D tank-mixed with glyphosate resulted in 7% or less visual broccoli or collard injury without influencing crop growth, biomass, early season yield, or total yield as long as the mulch was washed with 0.5 cm of irrigation before planting. These studies also demonstrated there were no differences between the 1× and 2× use rates with respect to all response variables measured. Results suggest that 2,4-D and glyphosate can be effectively removed from the surface of plastic mulch with irrigation or rainfall before planting broccoli and collard.

Locally Available Organic Waste for Counteracting Strawberry Decline in a Mountain Specialized Cropping Area

Crop decline caused by soil borne fungal pathogens affects specialized cropping systems such as fruit trees and strawberry. A study was carried out to investigate the effectiveness of pre-plant application of waste-derived biomasses in strawberry (Fragaria × ananassa) to reduce that phenomenon. A field experiment was carried out in an alpine strawberry specialized valley in South Tyrol (Italy), in a long term cultivated field selected for yield reduction over recent years. In July 2018, one month before strawberry transplanting, a field experiment with four soil treatments was set up: anaerobic digestate (solid fraction) of liquid manure, compost from anaerobic digestate of organic fraction of municipal solid waste (OFMSW), untreated control and Dazomet as chemical control. Plants were grown for two cycles (2019 and 2020). Dazomet always gave a significant (over 50%) increase in marketable yield per plant in both the years, anaerobic digestates did not improve strawberry production; compost from OFMSW gave phytotoxic effects in the first year, but improved strawberry yield like Dazomet in the second. Changes of rhizosphere bacterial populations and difference in root pathogen abundance, especially that of Dactylonectria torresensis, were correlated to the crop response to treatments. Findings suggest that waste-derived biomasses are a promising eco-friendly option for counteracting strawberry yield decline. Their positive impact was mostly linked to functional improvements induced by microbial variations. However, the use of such organic amendment requires careful evaluation of composition, doses and above all application times to reduce phytotoxic effects that in some cases can occur in the first months after application.

Nitrogen fertilization strategies for improved Mediterranean rainfed wheat and barley performance and water and nitrogen use efficiency

Adequate fertilization strategies are paramount to fulfill increasing demands for food, feed and fiber while reducing environmental impacts. However, their optimization under Mediterranean no-till systems has received little attention. The objective of this work was to assess winter cereal yield and water and N use efficiencies in a rainfed semiarid Mediterranean climate under (i) a range of pre-plant fertilizers [control without N fertilizer (0 N), and the following at 75 kg N ha−1: mineral N (MIN), swine slurry (SS), poultry manure (PM), and compost (COM)], (ii) fertilizer incorporation: no-tillage without incorporating (NT) or incorporation with a vibrocultivator (INC) and (iii) application of urea-ammonium nitrate solution (UAN) as top-dress as a control without UAN (UAN-) or 50 kg N ha−1 (UAN+). The experiment covered six cropping seasons (2012–2019).Pre-plant applications had similar responses in crop yield, biomass, N uptake, grain N, water-use efficiency for biomass (WUEb), and water-use efficiency for yield (WUEy) but were greater than 0 N. The lack of differences between pre-plant fertilizers would be explained by the high amount of residual N and the mineralized N during the crop cycle. Top-dress UAN increased WUEy and crop yield in all the cropping seasons by an average of 587 kg grain ha−1, which represented 18 % of the total annual production. Averaged across variables and the growing seasons, INC reduced soil water content and WUEb by 10 % (from 24.3 to 21.8 kg ha−1 mm−1). Also, INC reduced grain yield by 9% (from 3799 to 3450 kg ha−1) by reducing the number of spikes m-2 produced, pointing out that INC resulted in water deficit during the early reproductive period of the crop. While INC is often consider a best management practice to reduce NH3 volatilization losses from broadcast fertilizer applications, the results demonstrate that in rainfed Mediterranean agroecosystems water is more limiting than the N that could be potentially lost by volatilization.

Quantifying glyphosate plus 2,4-D or dicamba removal from the surface of totally impermeable film using analytical and bioassay techniques

AbstractThe loss of methyl bromide led vegetable growers to rely more heavily on herbicides to control weeds. Although herbicides can be effective, limited options in vegetable production challenge growers. Identifying new, effective tools to be applied over plastic mulch before planting, for improved weed control with minimal crop injury, would be beneficial. The objective of these experiments was to evaluate the persistence of preplant applications of glyphosate (1,125 or 2,250 g ae ha−1) plus 2,4-D (1,065 or 2,130 g ae ha−1) or dicamba (560 g ae ha−1) over plastic mulch, using analytical techniques and subsequent yellow squash and watermelon response. Glyphosate and 2,4-D were not analytically detected at damaging concentrations on plastic mulch when at least 3.5 cm of rainfall was received after application and before planting. In addition, bioassay results showing less than 10% visual injury for either squash and watermelon, with no growth or yield suppression observed, supported analytical results. In contrast, dicamba concentrations on plastic mulch, regardless of rainfall amount or time between application and planting, remained at damaging levels. Squash yields were reduced by dicamba applied 1 to 30 d before planting, whereas watermelon was more resilient. 2,4-D plus glyphosate applied preplant over plastic mulch can provide an additional herbicide option for vegetable growers. More research is needed to understand the impact of residual activity of 2,4-D when transplants land directly in holes in plastic mulch at the time of application. The relationship of dicamba with plastic mulch is complex, because the herbicide cannot be easily removed by rainfall. Thus, dicamba should not be included in a weed management system in plasticulture vegetable production.

Tolerance of Four Market Classes of Dry Beans to Tribenuron and Carfentrazone Applied Preplant

Limited information is available on the sensitivity of dry beans to tribenuron and carfentrazone applied preplant (PP). Four field trials were conducted at Exeter and Ridgetown, ON, Canada in 2019 and 2020 to determine the tolerance of azuki, kidney, small red and white beans to glyphosate (1800 g·ae·ha-1) + tribenuron (15 g·ai·ha-1), glyphosate (1800 g·ae·ha-1) + carfentrazone (35 g·ai·ha-1) and glyphosate (1800 g·ae·ha-1) + tribenuron (15 g·ai·ha-1) + carfentrazone (35 g·ai·ha-1) applied PP 1 - 2 days prior to seeding dry beans. Glyphosate + tribenuron, glyphosate + carfentrazone, and glyphosate + tribenuron + carfentrazone, applied PP, caused 5%, 5% and 9% bean injury at 1 WAE; 7%, 6% and 10% bean injury at 2 WAE and 6%, 5% and 8% bean injury at 4 WAE, respectively. At 8 WAE, there was 0, 1% and 4% injury in azuki bean; 1%, 2% and 2% injury in kidney bean; 3%, 2% and 3% injury in small red bean; and 6%, 3% and 2% injury in white bean with glyphosate + tribenuron, glyphosate + carfentrazone, and glyphosate + tribenuron + carfentrazone applied PP, respectively. The injury was significantly greater with glyphosate + tribenuron in small red and white beans compared to the azuki and kidney beans. There was no difference between injury levels among market classes of dry been with glyphosate + carfentrazone or glyphosate + tribenuron + carfentrazone applied PP. There was no effect of glyphosate + tribenuron, glyphosate + carfentrazone and glyphosate + tribenuron + carfentrazone on dry bean plant stand, maturity and seed yield. However, dry bean biomass was reduced as much as 15% with glyphosate + tribenuron and 13% with glyphosate + tribenuron + carfentrazone compared to the untreated control. Dry bean height was reduced 4% with glyphosate + tribenuron + carfentrazone but was not affected with other treatments. Based on these results, there is potential for using glyphosate plus tribenuron or carfentrazone for preplant weed management in dry bean production.

Combined Influence of Chitosan and Calcium Chloride on Fusarium Dry Rot Disease Under Field Conditions

Background: Fusarium dry rot disease caused by Fusarium sambucinum Fuckel (F. sambucinum) can infect the potato tubers in the field and during storage. Yield losses by F. sambucinum reach 60%. Traditional methods to control Fusarium dry rot are fungicides application, which led to developing many isolates resistant to these fungicides. Objective: The aim of this study is to evaluate the effect of calcium chloride (CaCl2) and chitosan, alone or in combination, on plant development, tuber yield, and Fusarium dry rot disease incidence under field conditions. Methods: Soil inoculated with F. sambucinum before planting. We treated the seed tubers with CaCl2 (0.5 or 1%), chitosan 0.5%, or both. The foliage was sprayed twice with CaCl2 (0.5 or 1%), 0.1% chitosan, or both. During the vegetation period, growth parameters, such as germination (%), plant height (cm), and branches number per plant, were measured. At harvest, we calculated the total and the marketable number of tubers and tuber yield. In addition, during storage, we assessed the incidence of Fusarium dry rot disease on tubers. Results: Results revealed that combined pre-planting application with 1% CaCl2 and 0.5% chitosan with 2 hours intervals, then spraying foliar with 1% CaCl2 and 0.1% chitosan twice with ten days intervals starting at 40 days after planting resulted in: a) increasing the germination, enhancing the growth parameters such as plant height and branches number per plant; b) enhancing the marketable tuber yield by 75.2 and 97.6% in Sante and Kolobok varieties, respectively; c) reducing Fusarium dry rot disease incidence by 61.9-72.7%. Conclusion: The work highlighted that the combined pre-planting and foliar application of CaCl2 and chitosan might be recommended for potato producers to reduce the incidence of Fusarium dry rot disease and augment yields.

Enhanced efficiency nitrogen fertilizers were not effective in reducing N2O emissions from a drip-irrigated cotton field in arid region of Northwestern China

Drip irrigation is an effective water-saving strategy for crop production in arid regions. However, limited information is available on how fertilizer nitrogen (N) management affects soil nitrous oxide (N2O) emission under drip irrigation. A two-year (2017–2018) field experiment was conducted in arid northwestern China to test management options of fertilizer N to reduce N2O emission and improve NUE of cotton (Gossypium hirsutum L.) under drip irrigation. Treatment included a factorial design of rate (120, 240 kg N ha−1) and source of N fertilizer (Urea, polymer-coated urea-ESN, stabilized urea with nitrification and urease inhibitors-SuperU), and an unfertilized Control. Urea was split-applied with irrigation water (fertigation) whereas ESN and SuperU were all side-banded at pre-plant. Crop yield and N uptake, soil mineral N concentrations, soil temperature and moisture, and N2O fluxes were determined. Across the two growing seasons, a single pre-plant application with ESN or SuperU significantly increased growing season cumulative N2O emissions (ƩN2O) by 29–47% and applied N-scaled emission factor (EF) by 57–83% compared to urea fertigation, irrespectively of application rate. In contrast, cotton yield, agronomic NUE, apparent N recovery (ANR), and yield-based N2O emission intensity (EI) were not affected by N source. Reducing N rate from 240 to 120 kg N ha−1 significantly decreased ƩN2O by 35% in 2017 and 36% in 2018 while simultaneously reduced cotton yield in both years. The increased N2O emissions with ESN and SuperU were attributed to greater availability of inorganic N resulted from one-time application at pre-plant and higher soil temperature. We concluded that fertigation with urea at the recommended rate is the best option to ensure agronomic productively and agronomic NUE with minimal risk of N2O emissions. In contrast, the benefit of enhanced efficiency N fertilizer is limited and recommendation on using of these products is challenging for arid croplands under drip irrigation.

Nematicidal Efficacy of Milbemectin against Root-Knot Nematodes.

The nematicidal efficacy of milbemectin and its commercial formulate Milbeknock® on (i) egg hatching, (ii) juvenile motility and (iii) infective capacity of root-knot nematodes was evaluated in vitro and in planta assays. Serial dilutions of pure milbemectin were tested against nematode eggs and juveniles and lethal concentrations LC50 and LC90 calculated. Exposure of egg masses to milbemectin at a concentration of 30 μg/mL for 72 h reduced egg hatching by 52%. The increase in exposure time to 240 h did not increase the egg hatching inhibition at the highest concentration 30 μg/mL (53%) but reduced egg hatching at 15 and 7 μg/mL by 35 and 24%, respectively, when compared to untreated controls. The inhibitory effect of milbemectin on juvenile motility ranged from 41 to 87% depending on its concentration, and this effect was persistent after rinsing the juveniles in water. The probabilistic dose–response model indicated that lethal concentrations of milbemectin for juvenile motility were LC50: 7.4 μg/mL and LC90: 29.9 μg/mL. The pre-plant application of Milbeknock® to soils infested with the nematode reduced its infective capacity by 98–99% compared to untreated soils in pot experiments. Milbeknock® reduced nematode soil population densities by 50–60% in natural infestations under field conditions. Milbemectin shows a high level of efficacy against root-knot nematodes as it reduces egg hatching, persistently immobilizes nematode juveniles, and reduces tomato root infection.

Timing and rate of nitrogen fertilization influence maize yield and nitrogen use efficiency.

Timing and rate of nitrogen (N) fertilizer application can influence maize (Zea mays L.) grain yield, N uptake, and nitrogen use efficiency (NUE) parameters, but results have been inconsistent across the upper Midwest. This study compared single (fall and preplant) and split applications of differing N rates for maize under irrigated conditions on loamy sand at Becker, MN and under rainfed conditions on loam and clay loam soils at Lamberton, MN and Waseca, MN, respectively, in 2014 to 2016. Fall and preplant applications of N were applied at recommended and 125% of recommended rates (RN) according to University of Minnesota guidelines. Split-application treatments included a two-way (Sp, applied at 75% and 100% of RN) and a three-way split (TSp applied at 50%, 75%, and 100% of RN), with the total N rate equally split among application times. At Becker, maize grain yield with TSp was 12.6 to 15.7 Mg ha-1 among years and significantly greater than that with fall or preplant treatments. The TSp treatment also improved agronomic efficiency (AE) and recovery efficiency (RE) by an average of 30% over fall or preplant treatments. At Lamberton, maize grain yield, AE and RE did not differ among treatments. However, TSp75 improved AE by 8.3 kg kg-1 while producing comparable yields to fall and preplant treatments. At Waseca, Sp or TSp improved grain yield and AE compared with fall treatments. These results suggest that split applications of N can increase maize grain yield, AE, and RE on irrigated coarse-textured soils and applying N fertilizer near planting or as a split application can improve N management on non-irrigated clay loam soils.

Weed control and soybean injury from preplant vs. preemergence herbicide applications

AbstractPalmer amaranth is one of the most troublesome weeds of soybean in the United States. To effectively control this weed it is necessary to optimize timing of PRE residual herbicides to mitigate Palmer amaranth emergence. Field studies were conducted in 5 site-years to assess the effect of application timing 12 to 16 d prior to planting (preplant) and at planting (PRE) on soybean injury and longevity of Palmer amaranth control using five residual herbicide treatments. A reduction in longevity of Palmer amaranth control was observed when S-metolachlor + metribuzin and flumioxazin + chlorimuron-ethyl were applied preplant vs. PRE in 2 of the 5 site years. Sulfentrazone, sulfentrazone + cloransulam-methyl, and saflufenacil + dimethenamid-P + pyroxasulfone + metribuzin did not reduce longevity of Palmer amaranth control when applied preplant vs. PRE in all 5 site-years. Visible estimates of soybean injury were lower at 21 d after planting when herbicides were applied 12 to 16 d preplant vs. PRE. These findings suggest that preplant applications can be used to reduce the potential for crop injury and may not result in reduced longevity of control when herbicides with a prolonged residual activity are used. Preplant herbicides increase the likelihood of the residuals being activated prior to subsequent weed emergence as opposed to PRE herbicides applied at soybean planting.