Net global warming potential index rather than soil carbon stock change could provide better understanding of the carbon balance in soil systems.

This study was conducted to determine the soil organic carbon (SOC) stock change factor for green manure crops that was developed by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 method and compare this with the net global warming potential (GWP) index that is used to evaluate the contribution of green manuring to global warming. Four treatments were barley (Hordeum vulgare L.; B), hairy vetch (Vicia villosa R.; HV), a barley/hairy vetch mixture (BHV) and a conventional treatment (C). The aboveground biomass of green manure crops was incorporated into the soil on 25 May 2018, 26 April 2019, 29 April 2020, 30 April 2021 and 2 May 2022. Maize (Zea mays L.) was transplanted as the subsequent crop after the incorporation of green manures. SOC stock decreased with green manures, even though carbon input with green manures, including B, HV and BHV, was greater than that with C. The mean value of the SOC stock change factor for green manure crops, including B, HV and BHV was 0.627 and was significantly lower than that of the C. However, the net GWP also decreased with the incorporation of green manure crops, and the mean value of the relative net GWP index across B, HV and BHV was 0.853. These conflicting results were caused by different estimation methods between annual SOC change (△SOC) and net GWP. The estimation of SOC stock change using △SOC suggested by the IPCC method may overestimate the contribution of green manure crops to global warming. The net GWP method with comprehensive input and output of carbon in the soil system could provide a better understanding of the carbon balance in soil systems. In the current study, the comparison of △SOC and net GWP was conducted for at one site of upland soil for 5 years. Therefore, further research on estimating the effect of green manure crops on net GWP in various types of soil for longer years should be conducted.

Heterogeneity Assessment of Kenaf Breeding Field through Spatial Dependence Analysis on Crop Growth Status Map Derived by Unmanned Aerial Vehicle.

The investigation of quantitative phenotypic traits resulting from the interaction between targeted genotypic traits and environmental factors is essential for breeding selection. Therefore, plot-wise controlled environmental factors must be invariable for accurate identification of phenotypes. However, the assumption of homogeneous variables within the open-field is not always accepted, and requires a spatial dependence analysis to determine whether site-specific environmental factors exist. In this study, spatial dependence within the kenaf breeding field was assessed in a geo-tagged height map derived from an unmanned aerial vehicle (UAV). Local indicators of spatial autocorrelation (LISA) were applied to the height map using Geoda software, and the LISA map was generated in order to recognize the existence of kenaf height status clusters. The spatial dependence of the breeding field used in this study appeared in a specific region. The cluster pattern was similar to the terrain elevation pattern of this field and highly correlated with drainage capacity. The cluster pattern could be utilized to design random blocks based on regions that have similar spatial dependence. We confirmed the potential of spatial dependence analysis on a crop growth status map, derived by UAV, for breeding strategy design with a tight budget.

Effects of Nitrogen Deficiency and Resupply on the Absorption of Mineral Nutrients by Tangor Cultivar 'Shiranuhi' (Citrus unshiu × C. sinensis) Grown in a Hydroponic System.

Tangor (Citrus unshiu × C. sinensis) cultivars obtained through interspecific hybridization have gained popularity in various countries, including South Korea. However, tangor has a relatively short history of cultivation and thus has been less well researched in terms of physiology and opping technology compared to mandarin. In addition, although tangor grows more vigorously than mandarin and thus has high nutrient demands and longer harvest time, it is more prone to various physiological disorders. Furthermore, the demand for nutrients could vary depending on the cultivars even within the same species. Thus, the current study examined the effects of nitrogen deficiency and resupply on the uptake of mineral nutrients using a specific cultivar 'Shiranuhi' as a case study. In this study, the tangor cultivar 'Shiranuhi' was cultivated in a hydroponics system, which allows the control of nutrient contents, and changes in mineral nutrient contents under nitrogen deficiency and nitrogen resupply were examined. Based on this, the results show the straightforward relationship between nitrogen and other mineral nutrients under a hydroponic system applying the cultivation of tangor. This implies that the hydroponics system can be applied to tangor cultivation and efficiently and widely expanded in Northeast Asia, and the income of growers will increase through the production of high-quality fruits.

Discrete Infomax Codes for Supervised Representation Learning.

For high-dimensional data such as images, learning an encoder that can output a compact yet informative representation is a key task on its own, in addition to facilitating subsequent processing of data. We present a model that produces discrete infomax codes (DIMCO); we train a probabilistic encoder that yields k-way d-dimensional codes associated with input data. Our model maximizes the mutual information between codes and ground-truth class labels, with a regularization which encourages entries of a codeword to be statistically independent. In this context, we show that the infomax principle also justifies existing loss functions, such as cross-entropy as its special cases. Our analysis also shows that using shorter codes reduces overfitting in the context of few-shot classification, and our various experiments show this implicit task-level regularization effect of DIMCO. Furthermore, we show that the codes learned by DIMCO are efficient in terms of both memory and retrieval time compared to prior methods.

Colored LED Lights: Use One Color Alone or with Others for Growth in Hedyotis corymbosa In Vitro?

In recent years, light-emitting diode (LED) technology has been applied to improve crop production and induce targeted biochemical or physiological responses in plants. This study investigated the effect of different ratios of blue 450 nm and red 660 nm LEDs on the overall plant growth, photosynthetic characteristics, and total triterpenoid production in the leaves of Hedyotis corymbosa in vitro plants. The results showed that a high proportion of blue LED lights had a positive effect on enhancing photosynthesis and the overall biomass. In addition, blue LED lights were shown to be more effective in controlling the production of the total triterpenoid content compared with the red LED lights. Moreover, it was also found that plants grown under a high proportion of red LEDs exhibited reduced photosynthetic properties and even induced damage to the photosynthetic apparatus, which indicated that the blue or red LED lights played contrary roles in Hedyotis corymbosa.

Deposition of Fukushima nuclear power plant accident-derived radiocesium in the soils of Jeju Island, Korea, and evidence for long- and short-lived radionuclides in rainwater.

In this study, we investigated the concentrations of Fukushima nuclear power plant accident (FNPPA)-derived radiocesium (134Cs, 137Cs) deposited in the topsoil of Jeju Island, Korea. We also evaluated the soil inventories of radionuclides and compared the concentrations deposited by rainwater and fallout. We present the first evidence of FNPPA-derived radionuclides directly entering the environment of Jeju Island. In the case of FNPPA-derived 134Cs in soil, only a trace amount was identified in the surface layer (1 cm depth), whereas 137Cs derived from past atmospheric deposition of nuclear testing were detected along with those derived from the nuclear power plant accident. The total measured radiocesium (134Cs + 137Cs) indicates that although the value obtained from soils was slightly lower, both values were within the same order of magnitude. Of the FNPPA-derived radiocesium deposited in the soil, the impact from April 2011 was the largest at most sampling sites indicating that the radioactive plume directly covered Jeju Island. Furthermore, a variety of long- and short-lived gamma-emitting radionuclides were detected in the rainwater samples collected on April 7, 2011. Among them, short-lived radionuclides such as 140La, 110mAg, 95Nb, 125Sb, 113Sn, 129Te, 129mTe, 132Te, 132I, and 136Cs, were observed. The findings of this study provide evidence for the direct effects of FNPPA-derived radionuclides in Jeju Island. This is the first location in Korea and the first in the entire East Asian region, excluding Japan that is confirmed to have been directly affected FNPP accident.