[Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a greenhouse. [Method] The experiment was carried out in a typical 6-yea...[Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a greenhouse. [Method] The experiment was carried out in a typical 6-year-old greenhouse,in which cucumber crops were cultivated twice each year(in spring and autumn),and catch crops were planted in summer. The total number of nematodes was counted and nematode community indices were calculated after collecting soil samples in different stages. [Result] Total nematode abundance was decreased in the soils of catch crop in contrast with former crops(cucumber crops). The abundance of the nematode community was reduced in the treatment of crop rotation compared to the soils of catch crop. In addition, the number of nematode taxa was significantly reduced by the treatment of crown daisy compared to the treatments of following crops. Crop rotation regulated the functional composition of the nematode community by increasing the omnivores-predators functional group and decreasing the relative abundance of root herbivores. [Conclusion] These results indicate that crop rotation affects the nematode community in abundance, diversity and functional composition of the nematode community and crown daisy can be served as the most appropriate catch crop in the greenhouse.展开更多
It is of great significance to use underwater video and image processing technology to detect and analyze fish behaviors.In this paper,an Oplegnathus image dataset for fish behaviors study by deep learning algorithm i...It is of great significance to use underwater video and image processing technology to detect and analyze fish behaviors.In this paper,an Oplegnathus image dataset for fish behaviors study by deep learning algorithm is constructed,and the data is captured from two cameras(one above water and another below water);and then an improved Neural Network model based on multi-scale features is proposed for fish behaviors learning auto-matically.To overcome the occlusion and blur problems of the images,the lightweight neu-ral network MobileNet-SSD is improved by adding a dilate convolution,and SE blocks are added to the feature maps at different scales to establish a self-attention mechanism;the Focal Loss function is used to calculate the classification loss and to balance the propor-tion of background and target samples.The results of the experiments show that the aver-age behaviors detection accuracy of our method reach 90.94%and 88.36%in both overwater and underwater datasets.展开更多
基金supported by a Key Grant from the Earmarked Fund for Beijing Leaf Vegetables Innovation Team of Modern Agro-industry Technology Research System (blvt-08)the Natural Science Foundation of Beijing (Project 6972014)the National Science Foundation of China (Grant No. 30972034)
文摘[Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a greenhouse. [Method] The experiment was carried out in a typical 6-year-old greenhouse,in which cucumber crops were cultivated twice each year(in spring and autumn),and catch crops were planted in summer. The total number of nematodes was counted and nematode community indices were calculated after collecting soil samples in different stages. [Result] Total nematode abundance was decreased in the soils of catch crop in contrast with former crops(cucumber crops). The abundance of the nematode community was reduced in the treatment of crop rotation compared to the soils of catch crop. In addition, the number of nematode taxa was significantly reduced by the treatment of crown daisy compared to the treatments of following crops. Crop rotation regulated the functional composition of the nematode community by increasing the omnivores-predators functional group and decreasing the relative abundance of root herbivores. [Conclusion] These results indicate that crop rotation affects the nematode community in abundance, diversity and functional composition of the nematode community and crown daisy can be served as the most appropriate catch crop in the greenhouse.
基金The work of this paper is jointly supported by the National Natural Science Foundation of China(U1706220,61472172)the Yantai Key R&D Project(2017ZH057,2018ZDCX003,2019XDHZ084).
文摘It is of great significance to use underwater video and image processing technology to detect and analyze fish behaviors.In this paper,an Oplegnathus image dataset for fish behaviors study by deep learning algorithm is constructed,and the data is captured from two cameras(one above water and another below water);and then an improved Neural Network model based on multi-scale features is proposed for fish behaviors learning auto-matically.To overcome the occlusion and blur problems of the images,the lightweight neu-ral network MobileNet-SSD is improved by adding a dilate convolution,and SE blocks are added to the feature maps at different scales to establish a self-attention mechanism;the Focal Loss function is used to calculate the classification loss and to balance the propor-tion of background and target samples.The results of the experiments show that the aver-age behaviors detection accuracy of our method reach 90.94%and 88.36%in both overwater and underwater datasets.
