Evaluation of Sulfentrazone Alone or in Combination with Other PRE and POST Herbicides for Weed Control in Tomato (Solanum lycopersicum) and Strawberry (Fragaria ×ananassa)

Sulfentrazone was recently registered for use in tomato and strawberry in Florida. Field experiments were conducted at the Gulf Coast Research and Education Center in Wimauma, FL, to evaluate PRE sulfentrazone applications when applied on flat soil 30 days before bed formation (PRE-f), on the bed top immediately before laying plastic mulch (PRE-t), applied PRE-t as a tank mix with other PRE herbicides, or PRE-t followed by POST halosulfuron or rimusulfuron (POST). Sulfentrazone did not damage the tomato and strawberry crop and had no effect on strawberry and tomato fruit yield. It was as effective as the industry standards but none of the evaluated herbicide treatments provided adequate weed control. POST halosulfuron in tomato resulted in significantly greater nutsedge control at 11 (14%) and 13 (27%) weeks after initial treatment (WAIT) compared with other treatments in Fall 2019 and Spring 2020, respectively. However, in tomato, tank-mixing sulfentrazone with S-metolachlor or metribuzin did not enhance nutsedge control. Weed control did not improve with increased rates or with the use of PRE-f followed by (fb) PRE-t applications in tomato. PRE-t sulfentrazone fb POST halosulfuron was an efficient nutsedge management option in tomato. Sulfentrazone alone did not effectively control weeds in tomato or strawberry. Increased rates of sulfentrazone with the use of PRE-f fb PRE-t sulfentrazone applications did reduce (34%) total weed density in strawberry.

Effect of Mulching on Growth and Yield of Peanut (Arachis hypogaea L.) on the Coastal Sandy Land in Nghe An Province, Vietnam

Background: Peanut (Arachis hypogaea L.) is one of the oil and cash crops in Vietnam. However, owing to the lack of appropriate management practices, the production and the area under cultivation of peanut have remained low. Mulches are the key factors contributing to promoting crop development and early harvest and increasing yields. Methods: The experiment consisted of three mulch treatments, viz., plastic mulch, straw mulch and no-mulch control. All the treatments were replicated thrice in a complete randomized block design. Result: In the conditions of mulch, the plant growth parameters (germination rate, growing time, plant height, number of branches per plant), leaf area index, the number of nodules per plant, dry matter accumulation, yield components and yield of peanut was much higher than that of no-mulch control. Among the mulches, plastic mulch was found superior to straw mulch in the pod yields and water-use efficiency and moisture conservation, thereby can be considered as a reliable practice for increasing the productivity of peanut on the coastal sandy land in Nghe An province, Vietnam.

Comparing Overhead versus Drip Irrigation for Production of Three Cultivars of Romaine Lettuce on Biodegradable Plastic Mulch

Growers seeking alternatives to traditional polyethylene plastic mulch may use biodegradable plastic mulches (BDMs). However, plasticulture systems typically also use plastic drip tape underneath the mulch, which must be removed from the field and disposed of at the end of the season, making tilling the BDM into the soil more difficult and expensive. A potential solution to this dilemma may be to use other irrigation methods, such as overhead sprinklers, that could be more easily removed from the field and reused from year to year. At Knoxville, TN, in 2019 and 2020, we grew three cultivars of romaine lettuce (Lactuca sativa) on BDM with two irrigation systems (overhead sprinklers above the mulch and drip irrigation tape under the mulch) to compare water use, disease, and yield in these two irrigation systems. Water use was higher in overhead vs. drip irrigation in both years; however, the difference in water use was much smaller in 2019 due to higher rainfall amounts during the time period the lettuce was growing in the field (March to May). Disease incidence and severity were very low both years for both irrigation systems. There were no differences in marketable yield (number of heads) between irrigation treatment in 2019. In 2020, marketable yield by number was greater in the drip vs. overhead irrigation treatment. Unmarketable yield in 2019 was due to heads that were too small; in 2020, unmarketability was predominantly due to tipburn in overhead irrigated ‘Jericho’. Overall, marketable lettuce yield did not differ between irrigation treatments in 2019 and was similar for ‘Parris Island Cos’ in 2020. Although quantitative weed counts were not made, observations of weed pressure between rows showed that weed pressure was higher in overhead irrigated compared with drip irrigated subplots. This highlights the need to have a between-row weed management program in place. The results of this study suggest that with attention to cultivar and weed management, overhead irrigation could be a viable alternative to drip irrigation for lettuce production on BDM, especially for early spring lettuce when rainfall is historically more plentiful.

The Succession of Bacterial Community Attached on Biodegradable Plastic Mulches During the Degradation in Soil

Despite the increasing application of biodegradable plastic mulches (BDMs) in agriculture, the colonization and succession of the attached microbial community on BDMs during their degradation processes remain poorly characterized. Here, we buried four types of commonly used BDMs, including pure polylactic acid (PLA), pure polybutylene adipate terephthalate (PBAT), and two mixtures of PLA and PBAT (85:15 and 15:85 w/w), and one classic polyethylene (PE) mulch in soil for 5 months. Both plastic components and incubation time significantly shaped the β-diversities of microbiota on the plastic mulches (p < 0.001). Meanwhile, the microbial compositions and community structures on BDMs were significantly different from PE mulch, and when excluding PE mulch, the microbiota varied more with time than by the composition of the four BDMs. The orders Burkholderiales and Pseudonocardiales were dominant on most BDMs across different time points. The genus Ramlibacter was revealed as a common biomarker for both PLA and PBAT by random-forest model, and all biomarkers for the BDMs belonged to the dominant order Burkholderiales. In addition, degradation-related and pathogen-related functional taxa were enriched in all mulches among all 40 functional groups, while surprisingly, potential pathogens were detected at higher levels on BDMs than PE. For community assembly on all mulches, the drift and dispersal processes played more important roles than selection, and in particular, the contribution of stochastic drift increased during the degradation process of BDMs while selection decreased, while the opposite trend was observed with PE mulch. Overall, our results demonstrated some degradation species and pathogens were specifically enriched on BDMs, though stochastic processes also had important impacts on the community assembly. It suggested that, similar to conventional plastic mulch, the increased usage of BDMs could lead to potential hazards to crops and human health.

Study of the Effect of Mulching Materials on Weed Control in Saffron Cultivation in Eastern Morocco

Saffron (Crocus sativus L.) is cultivated in many countries for its culinary and medicinal values. The production of saffron is limited by several factors, including weed infestation, which causes damage to the crop in terms of quantity and quality. However, little information is available on the different weed management strategies for saffron cultivation, as most of the strategies implemented are developed for large-scale and conventional agriculture. As a result, they are not applicable or affordable for organic or smallholder farmers, as is the case for saffron cultivation. The objective of this study is to compare the effectiveness of plastic mulching versus mulching in controlling weeds in saffron cultivation in the eastern region of Morocco. During the trial, which was conducted in 2018, the parameters measured correspond, on the one hand, to morphometric measurements and determination of saffron stigma yield and, on the other hand, to the determination of density, dry biomass, and weed control capacity. Compared to the control, mulching reduced the population and dry biomass of the most formidable weeds such as Cynodon dactylon, Aster squamatus, Cyperus rotundus, and Convolvulus arvensis. The average stigmata yield from plastic mulch treatment was 9% higher than of the control, and the number of leaves, leaf area, number, weight, and percentage of daughter corms with large diameter were higher for plants grown under mulch. Overall, the results of this study showed that the use of PE (polyethylene) mulch effectively reduced weed populations and improved saffron yield and vegetative growth.

Can hemp hurd or paper mulch and biochar application improve weed management in matted-row strawberry production systems?

During 2015 and 2016, studies were conducted at Absaraka and Dickinson, North Dakota to evaluate the impacts of hemp (applied at 1156 m3 ha−1) and commercial paper mulch, as well as soil-applied biochar (applied at 11.25 m3 ha−1), on weed suppression and strawberry growth during the establishment year, and on weed suppression and strawberry yield during the production year, in a matted row production (MRP) system. During 2015, biochar influenced dry weed biomass only within the hemp mulch, with slightly more weed biomass associated with biochar application compared to zero biochar (3.1 vs 0.4 g m−2), suggesting that biochar may have increased weed germination and/or emergence from beneath hemp mulch. Biochar application also slightly increased soil pH, from 6.9 in non-amended soil to 7.0 in amended soil. Strawberry runner number during 2015 was greater in association with hemp or paper mulch compared to zero mulch (4.5 and 4.9 vs 2.4 runners plant −1, respectively). This result mirrored a similar differential in per berry mass across sites (7.6 and 7.4 vs 6.2 g berry −1 for hemp mulch, paper mulch and zero mulch, respectively). These results may be related to hemp and paper mulch reducing maximum soil temperatures during summer 2015. During the establishment year, both hemp and paper mulch suppressed weeds well compared to zero mulch, although at Absaraka hemp mulch provided slightly better weed suppression than paper mulch. During the production year, both mulches continued to suppress weeds compared to zero mulch at Dickinson. However, at Absaraka, only hemp mulch provided weed suppression compared to zero mulch, possibly because of faster paper degradation caused by greater numbers of large precipitation events and greater relative humidity at Absaraka compared to Dickinson. Weeds were removed from plots during 2015 to allow separation of weed suppression from other possible mulch impacts; therefore, yield data do not reveal striking differences among mulch treatments. Because previous research has demonstrated the impact of weed management during the establishment of strawberries in a matted row system, we concluded that hemp mulch may provide more durable weed suppression compared to paper mulch, which would increase strawberry yield protection in an MRP system. Material cost may be an issue for implementing hemp mulch, as hemp hurd cost was 25 times paper mulch at the application rates used in this study. However, hemp mulch could still be a beneficial option, especially for organic strawberry growers desiring a renewable and environmentally sound replacement for plastic mulch who are able to find affordable local sources of this material.

The Food Safety Risks of Harvesting Dropped and Drooping Produce: A Review

The Food Safety Modernization Act’s Produce Safety Rule sets forth minimum standards for fruit and vegetable production in the U.S. One provision states that growers must not harvest dropped produce, as damage or ground contact may contaminate produce. An unpublished survey of 2020 food safety inspections conducted by the Northeast Center to Advance Food Safety identified handling of dropped covered produce as a common misunderstanding and non-compliance issue among Northeast growers. In considering this provision’s on-farm practicality, this review was conducted to evaluate the risks associated with dropped and drooping produce to guide growers in making informed risk management decisions, and to answer the following questions: 1) What are the risk factors that influence transferability of pathogens from touching the ground to produce?; and 2) What are the risks associated with harvesting dropped or drooping produce covered under the Rule? A search of online databases found twelve relevant publications, which highlight moisture, contact time, and crop features as affecting contamination rates from a ground surface to a crop surface. Soil and mulch pose a differential risk, with bare soil generally presenting a lower risk than plastic mulch. The effects of other mulch types is unclear. Mulches may promote pathogen persistence in soil, though they may also protect produce from contaminated soils. These studies are limited in their scope and applicability and most do not directly address dropped produce. Future research is needed to clarify the varying effects of dropped and drooping produce, the impact of ground surface type on pathogen survivability and transfer, soil and crop features that facilitate contamination, and post-harvest risks of harvesting dropped or drooping produce. A comprehensive understanding will guide growers in implementing preventive measures and better managing risk in a way practicable to their farm's unique conditions.

Estimating Yield and Water Productivity of Tomato Using a Novel Hybrid Approach

Water productivity (WP) of crops is affected by water–fertilizer management in interaction with climatic factors. This study aimed to evaluate the efficiency of a hybrid method of season optimization algorithm (SO) and support vector regression (SVR) in estimating the yield and WP of tomato crops based on climatic factors, irrigation–fertilizer under the drip irrigation, and plastic mulch. To approve the proposed method, 160 field data including water consumption during the growing season, fertilizers, climatic variables, and crop variety were applied. Two types of treatments, namely drip irrigation (DI) and drip irrigation with plastic mulch (PMDI), were considered. Seven different input combinations were used to estimate yield and WP. R2, RMSE, NSE, SI, and σ criteria were utilized to assess the proposed hybrid method. A good agreement was presented between the observed (field monitoring data) and estimated (calculated with SO–SVR method) values (R2 = 0.982). The irrigation–-fertilizer parameters (PMDI, F) and crop variety (V) are the most effective in estimating the yield and WP of tomato crops. Statistical analysis of the obtained results showed that the SO–SVR hybrid method has high efficiency in estimating WP and yield. In general, intelligent hybrid methods can enable the optimal and economical use of water and fertilizer resources.