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Strawberries (Fragaria × ananassa Duch.) are highly perishable fruit. Timely prediction of yield is crucial for labor management and marketing decision-making. This study demonstrates the use of high-resolution ground-based imagery, in addition to previous yield and weather information, for yield prediction throughout the season at different intervals (3–4 days, 1 week, and 3 weeks pre-harvest). Flower and fruit counts, yield, and high-resolution imagery data were collected 31 times for two cultivars (‘Florida Radiance’ and ‘Florida Beauty’) throughout the growing season. Orthorectified mosaics and digital surface models were created to extract canopy size variables (canopy area, average canopy height, canopy height standard deviation, and canopy volume) and visually count flower and fruit number. Data collected at the plot level (6 plots per cultivar, 24 plants per plot) were used to develop prediction models. Using image-based counts and canopy variables, flower and fruit counts were predicted with percentage prediction errors of 26.3% and 25.7%, respectively. Furthermore, by adding image-derived variables to the models, the accuracy of predicting out-of-sample yields at different time intervals was increased by 10–29% compared to those models without image-derived variables. These results suggest that close-range high-resolution images can contribute to yield prediction and could assist the industry with decision making by changing growers’ prediction practices.
Amr Abd-Elrahman; Feng Wu; Shinsuke Agehara; Katie Britt. Improving Strawberry Yield Prediction by Integrating Ground-Based Canopy Images in Modeling Approaches. ISPRS International Journal of Geo-Information 2021, 10, 239 .
AMA StyleAmr Abd-Elrahman, Feng Wu, Shinsuke Agehara, Katie Britt. Improving Strawberry Yield Prediction by Integrating Ground-Based Canopy Images in Modeling Approaches. ISPRS International Journal of Geo-Information. 2021; 10 (4):239.
Chicago/Turabian StyleAmr Abd-Elrahman; Feng Wu; Shinsuke Agehara; Katie Britt. 2021. "Improving Strawberry Yield Prediction by Integrating Ground-Based Canopy Images in Modeling Approaches." ISPRS International Journal of Geo-Information 10, no. 4: 239.
Huanglongbing (HLB) is a devastating citrus disease worldwide. A three-pronged approach to controlling HLB has been suggested, namely, removal of HLB-symptomatic trees, psyllid control, and replacement with HLB-free trees. However, such a strategy did not lead to successful HLB control in many citrus producing regions. We hypothesize this is because of the small-scale or incomprehensive implementation of the program, conversely, a comprehensive implementation of such a strategy at regional level can successfully control HLB. Here we investigated the effects of region-wide comprehensive implementation of this scheme to control HLB in Gannan region, China, with a total planted citrus acreage of over 110,000 ha from 2013–2019. With the region-wide implementation of comprehensive HLB management, overall HLB incidence in Gannan decreased from 19.71% in 2014 to 3.86% in 2019. A partial implementation of such a program (without a comprehensive inoculum removal) at the regional level in Brazil resulted in HLB incidence increasing from 1.89% in 2010 to 19.02% in 2019. A dynamic regression model analyses predicated that in a region-wide comprehensive implementation of such a program, HLB incidence would be controlled to a level of less than 1%. Economic feasibility analyses showed that average net profits were positive for groves that implemented the comprehensive strategy, but negative for groves without such a program over a ten-year period. Overall, the key for the three-pronged program to successfully control HLB control is the large scale (region-wide) and comprehensiveness in implementation. This study provides valuable information to control HLB and other endemic diseases worldwide.
Xiaoyong Yuan; Cixiang Chen; Renato Bassanezi; Feng Wu; Zheng Feng; Damin Shi; Yimin Du; Ling Zhong; Balian Zhong; Zhanjun Lu; Jinyun Li; Xiang Song; Miss Yan Hu; Zhigang Ouyang; Xiujun Liu; Jinzhao Xie; Xi Rao; Xi Wang; Dapeng Wu; Zhengfei Guan; Nian Wang. Region-wide comprehensive implementation of roguing infected trees, tree replacement, and insecticide applications successfully controls citrus HLB. Phytopathology® 2020, 1 .
AMA StyleXiaoyong Yuan, Cixiang Chen, Renato Bassanezi, Feng Wu, Zheng Feng, Damin Shi, Yimin Du, Ling Zhong, Balian Zhong, Zhanjun Lu, Jinyun Li, Xiang Song, Miss Yan Hu, Zhigang Ouyang, Xiujun Liu, Jinzhao Xie, Xi Rao, Xi Wang, Dapeng Wu, Zhengfei Guan, Nian Wang. Region-wide comprehensive implementation of roguing infected trees, tree replacement, and insecticide applications successfully controls citrus HLB. Phytopathology®. 2020; ():1.
Chicago/Turabian StyleXiaoyong Yuan; Cixiang Chen; Renato Bassanezi; Feng Wu; Zheng Feng; Damin Shi; Yimin Du; Ling Zhong; Balian Zhong; Zhanjun Lu; Jinyun Li; Xiang Song; Miss Yan Hu; Zhigang Ouyang; Xiujun Liu; Jinzhao Xie; Xi Rao; Xi Wang; Dapeng Wu; Zhengfei Guan; Nian Wang. 2020. "Region-wide comprehensive implementation of roguing infected trees, tree replacement, and insecticide applications successfully controls citrus HLB." Phytopathology® , no. : 1.
This study quantifies the effect of weather factors on fumigation efficacy in terms of weed control, tomato yield, and the overall economic performance of fumigants. High soil temperature was found to reduce the efficacy of all fumigants against nutsedge, while rainfall only reduced the efficacy of a limited number of fumigants. The fumigants’ economic performance over a range of weather conditions was further simulated to identify the fumigant that is most effective under diverse weather conditions. The results show that although 1,3-D:Pic:Kpam outperforms methyl bromide over the experiment period, methyl bromide is still the best treatment when accounting for the impact of weather variability. The study illustrates the sensitivity of fumigant efficacy to weather conditions and the importance of achieving consistent and sustainable efficacy. The regression model and the expected utility model, along with the simulation techniques, form a useful tool that can be applied across regions or crops.
Feng Wu; Berdikul Qushim; Zhengfei Guan; Nathan S. Boyd; Gary E. Vallad; Andrew MacRae; Tyler Jacoby. Weather Uncertainty and Efficacy of Fumigation in Tomato Production. Sustainability 2019, 12, 199 .
AMA StyleFeng Wu, Berdikul Qushim, Zhengfei Guan, Nathan S. Boyd, Gary E. Vallad, Andrew MacRae, Tyler Jacoby. Weather Uncertainty and Efficacy of Fumigation in Tomato Production. Sustainability. 2019; 12 (1):199.
Chicago/Turabian StyleFeng Wu; Berdikul Qushim; Zhengfei Guan; Nathan S. Boyd; Gary E. Vallad; Andrew MacRae; Tyler Jacoby. 2019. "Weather Uncertainty and Efficacy of Fumigation in Tomato Production." Sustainability 12, no. 1: 199.
The Florida tomato industry is facing challenges of increased production costs and decreased yields resulting from the methyl bromide (MBr) phase-out under the Montreal Protocol for environmental concerns. MBr and several accepted alternative soil fumigant systems are analyzed in this study from an economic perspective. This article focuses on identifying optimal fumigant systems by analyzing the cost effectiveness and economic risk associated with MBr and several other commercially available soil fumigant systems using data collected from scientific field trials. The results obtained show that a 67:33 formulation of MBr: chloropicrin is the most cost-effective treatment, and no alternative fumigant systems investigated can substitute MBr cost-effectively in Florida tomato production. The analysis indicated that switching from MBr (67:33) to the new industry standard PicChlor 60 approximately resulted in a loss of $3,569 per acre in gross revenue and $1,656 per acre in profit using market prices in the 2013/14 season. Higher market prices would further increase the loss.
Xiang Cao; Zhengfei Guan; Gary E. Vallad; Feng Wu. Economics of fumigation in tomato production: the impact of methyl bromide phase-out on the Florida tomato industry. International Food and Agribusiness Management Review 2019, 22, 589 -600.
AMA StyleXiang Cao, Zhengfei Guan, Gary E. Vallad, Feng Wu. Economics of fumigation in tomato production: the impact of methyl bromide phase-out on the Florida tomato industry. International Food and Agribusiness Management Review. 2019; 22 (4):589-600.
Chicago/Turabian StyleXiang Cao; Zhengfei Guan; Gary E. Vallad; Feng Wu. 2019. "Economics of fumigation in tomato production: the impact of methyl bromide phase-out on the Florida tomato industry." International Food and Agribusiness Management Review 22, no. 4: 589-600.
The purpose of this paper is to propose a general framework for modeling heterogeneous risk preferences of agricultural producers and identifying the underlying factors that affect risk preferences. This paper nests the risk preference function in a general production decision framework to test and model producers’ risk preferences. The framework allows for both production and price risk, and accommodates potential inefficient behavior. Panel data and the GMM method are used in the empirical estimation. The results in this study confirmed the hypothesis of heterogeneous risk preferences. Farmers are found to have decreasing absolute risk aversion. Both farmer characteristics and socioeconomic factors have significant impact on producers’ risk preferences. The results suggest that ignoring heterogeneity in risk preferences across individuals and how non-wealth variables could affect farmers’ risk preferences could result in biased economic behavior analysis. It is generally assumed in the literature that risk preferences are homogeneous among farmers at given wealth. This is a strong assumption and there are abundant evidences that suggest otherwise. This paper makes contributions to the literature by proposing an approach to modeling heterogeneous risk preferences and identifying the factors that affect preferences.
Zhengfei Guan; Feng Wu. Modeling heterogeneous risk preferences. Agricultural Finance Review 2017, 77, 324 -336.
AMA StyleZhengfei Guan, Feng Wu. Modeling heterogeneous risk preferences. Agricultural Finance Review. 2017; 77 (2):324-336.
Chicago/Turabian StyleZhengfei Guan; Feng Wu. 2017. "Modeling heterogeneous risk preferences." Agricultural Finance Review 77, no. 2: 324-336.
In this interdisciplinary study we propose a modeling framework for deriving the optimal yield curve for strawberry production in Florida that maximizes the profit of growers given competition from California and Mexico and sensitive price responses to market supply. The model integrates both biological and economic constraints. The biological constraints for Florida production are formulated assuming that potential improvement of yield has genetic and horticultural limits, while economic constraints account for price changes in response to supply. The optimal yield curves derived show clear differences from the historical yield patterns observed in Florida, indicating that yields during the first 6 to 8 weeks of the season should be maximized to realistic limits and that total season yields should be limited to 27,465 and 32,415 kg/ha under two different yield distribution scenarios assuming current acreage and market demand. Obtaining optimal yield distributions under the two scenarios could generate $7685 and $14,293 per ha more profit, whereas the historical yield pattern will result in significant losses under assumed acreage, raising concerns about the sustainability of the industry. The results of this study will be used to guide efforts in breeding and improvement of cultural practices and will assist growers in making informed decisions on cultivars and technologies/practices to adopt to maximize profit. The methodology proposed can be adapted to other regions or countries and used for other perishable crops with extended production seasons.
Feng Wu; Zhengfei Guan; Vance Whitaker. Optimizing yield distribution under biological and economic constraints: Florida strawberries as a model for perishable commodities. Agricultural Systems 2015, 141, 113 -120.
AMA StyleFeng Wu, Zhengfei Guan, Vance Whitaker. Optimizing yield distribution under biological and economic constraints: Florida strawberries as a model for perishable commodities. Agricultural Systems. 2015; 141 ():113-120.
Chicago/Turabian StyleFeng Wu; Zhengfei Guan; Vance Whitaker. 2015. "Optimizing yield distribution under biological and economic constraints: Florida strawberries as a model for perishable commodities." Agricultural Systems 141, no. : 113-120.