Showing papers by "Atsushi Tsunekawa published in 2010"
TL;DR: Investigation of the effects of UV‐B radiation on reactive oxygen species (ROS) accumulation and antioxidant defense system in relation to germination, tube length and viability of maize pollen indicates that increased UV‐ B radiation decreased the pollen germination rate and tube length in vitro and also its fertilization ability in the field.
Abstract: The increase in UV-B radiation reaching the earth's surface has prompted extensive studies on the effects of UV-B on plants. However, most of these studies have not addressed the close characteristics related to future survival of plant populations. The purpose of this study was to investigate the effects of UV-B radiation on reactive oxygen species (ROS) accumulation and antioxidant defense system in relation to germination, tube length and viability of maize pollen. Our results indicate that increased UV-B radiation decreased the pollen germination rate and tube length in vitro and also its fertilization ability in the field. Production of O(2)(*-) and H(2)O(2) increased by UV-B radiation treatment, and their continuous accumulation resulted in lipid peroxidization. The activities of superoxide dismutase, catalase, peroxidase and DPPH-radical scavenging were decreased by increased UV-B radiation. The increased ROS and lipid peroxidization, and decreased activities of the antioxidants may be attributed to the effects of UV-B radiation on pollen germination, tube growth and fertilization ability.
56 citations
TL;DR: In this paper, the effects of land cover and slope aspect on soil organic carbon (SOC) storage on the Loess Plateau of China were investigated. And the results showed that the top 100 cm soil carbon was significantly higher in artificial grassland (2.49 kg m−2) than in cropland (1.69 kg−2).
Abstract: Changes in land cover from cropland to conservation can sequester carbon in soil. On the Loess Plateau of China, vast areas of sloping cropland were converted into forest and grassland to control soil erosion. The northern plateau is a topographically heterogeneous, semi-arid region. A good understanding of the change of soil organic carbon (SOC) storage on the plateau in the process of land-cover change is important for assessing environmental changes and planning future land cover. We selected four land-cover types (cropland, planted grassland, abandoned orchard, and secondary grassland), and two vegetation covers (Stipa bungeana and Caragana korshinskii) on shady and sunny slopes, to analyse the effects of land cover and slope aspect on SOC storage. Soil C in the top 100 cm was significantly (P<0.05) greater in artificial grassland (2.49 kg m−2) and secondary grassland (2.98 kg m−2) than in cropland (1.69 kg m−2). The SOC pool in the surface soil and throughout the 1-m profile followed the ord...
36 citations
TL;DR: Soil temperature and 7-day maximum/minimum combined passive microwave brightness temperature were employed to apply a soil freeze–thaw algorithm in northern China and Mongolia and suggested that changes in earth surface may cause extreme environmental events such as the dust emission in semi-arid and arid regions of East Asia.
29 citations
Journal Article•
TL;DR: Wang et al. as mentioned in this paper conducted a case study in the Zhifanggou watershed on China's Loess Plateau and used a Data-Envelopment-Analysis based on Malmquist TFP index approach to find out the changes of TFP, the sources of total factor productivity (TFP), and the determinant factors at a farm level.
Abstract: In 1999, the Grain for Green program (also known as Sloping Land Conversion program), one of the world's largest land-conservation programs, was launched in China It emphasizes both eco-environment rehabilitation and poverty alleviation, with the ultimate goal of sustainable development Total Factor Productivity (TFP) has important implications for conservation of the environment, enhancement of wellbeing, food self-sufficiency, and the sustainability of the program Using data from the year before and the ending year of the first phase, we did a case study in the Zhifanggou watershed on China's Loess Plateau We used a Data-Envelopment-Analysis based on Malmquist TFP index approach to find out the changes of TFP, the sources of TFP growth, and the determinant factors at a farm level We found that 1) TFP has been greatly improved after the implementation of the program and 2) the sole source of TFP growth is technological growth In contrast, the technical efficiency of farms under the improved technology has decreased; 3) farms with an unfavorable initial state benefited more after the introduction of the program; and 4) land terracing and access to credit contributed significantly to TFP growth and technological growth Land terracing is positively related to technical efficiency change, too Extension services are positively related to technological growth, while age is negatively related to technical efficiency change We therefore suggest a focus on terracing slopes, improving access to credit and extension services
12 citations
Journal Article•
TL;DR: The findings prompt policy suggestions that would facilitate labor mobility, provide more secure land tenure and increase land consolidation, while avoiding further withdrawal of cultivated land unless explicit measures to alleviate the potential impact on production efficiency are followed.
Abstract: A nonparametric frontier approach, data envelopment analysis, was used to calculate technical, pure technical, cost, allocative and scale efficiencies of 112 farms participating in the Grain for Green Program on the Loess Plateau in China. The results indicate substantial cost inefficiencies. The main source of cost inefficiency was allocative inefficiency although considerable technical inefficiency also exists. Technical inefficiency resulted slightly more from scale inefficiency than from pure technical inefficiency. Scale inefficiency was mostly due to the suboptimal scale of farms. Regression analysis of explanatory variables against technical efficiency, allocative efficiency and scale efficiency suggested that LG_Agri (indicator for farm size) was the only variable that was significantly related to all three efficiency indices. Other significant variables include Remittance Ratio (indicator for rural-urban migration), Tenancy Ratio (indicator for land tenancy) and Simpson Index (indicator for land fragmentation). Our findings prompt policy suggestions that would facilitate labor mobility, provide more secure land tenure and increase land consolidation, while avoiding further withdrawal of cultivated land unless explicit measures to alleviate the potential impact on production efficiency are followed.
9 citations
Journal Article•
TL;DR: In this article, several topics that are significant for sustainable agriculture and rural development for food security and environmental rehabilitation in dryland areas were stressed in this paper, including poverty and desertification.
Abstract: Drylands of the world cover 41% of the Earth's land surface and are a direct source of livelihood for 6.5 billion people, especially in developing countries. However, nearly all drylands are at risk of land degradation as a result of human activities. Poverty and desertification in dryland areas are major problems threatening sustainable agriculture and rural development in dryland areas.Several topics that are significant for sustainable agriculture and rural development for food security and environmental rehabilitation in dryland areas were stressed in this paper.
1 citations