Water management and crop production for food security in China: A review

Food security is a high priority issue on the Chinese political agenda. China’s food security is challenged by several anthropogenic, sociopolitical and policy factors, including: population growth; urbanization and industrialization; land use changes and water scarcity; income growth and nutritional transition; and turbulence in global energy and food markets. Sustained growth in agricultural productivity and stable relations with global food suppliers are the twin anchors of food security. Shortfalls in domestic food production can take their toll on international food markets. Turbulence in global energy markets can affect food prices and supply costs, affecting food security and poverty. Policy safeguards are needed to shield food supply against such forces. China must make unremitting policy responses to address the loss of its fertile land for true progress towards the goal of national food security, by investing in infrastructure such as irrigation, drainage, storage, transport, and agricultural research and institutional reforms such as tenure security and land market liberalization. The links between water and other development-related sectors such as population, energy, food, and environment, and the interactions among them require reckoning, as they together will determine future food security and poverty reduction in China. Climate change is creating a new level of uncertainty in water governance, requiring accelerated research to avoid water-related stresses.     

Insulin and IGF-I receptors and tyrosine kinase activity in carp ovaries: changes with reproductive cycle

Insulin and insulin-like growth factor I (IGF-I) receptors from carp ovaries were semipurified with wheat germ agglutinin at different moments of the reproductive cycle and their binding characteristics and tyrosine kinase activity were studied. Specific receptors for insulin and IGF-I were found. IGF-I receptors presented higher binding (23.8 ± 1.5%), number of receptors (965 ± 20fm/mg) and affinity (K_D 0.24 ± 0.03nM) than those shown for insulin receptors (4.1 ± 1%, 530 ± 85fm/mg and 0.85 ± 0.1nM, respectively). Insulin and IGF-I receptors have a tyrosine kinase activity which is not different from that found in muscle of the same species. Seasonal changes were found in binding, with maximum values for insulin and IGF-I reached at the end of pre-spawning period (June). However, while IGF-I binding was observed in all stages, insulin binding decreased in autumn and disappeared in winter, which suggests a different role for the two peptides in ovarian physiology.     

近10年来新疆耕地数量变化分析

新疆作为我国的农业大省以及21世纪重要的资源接替区,研究其耕地变化具有重要的现实意义。分析了1996以来新疆耕地数量的变化及其生态环境效应,借助SPSS软件,应用主成分分析方法分析了耕地变化的驱动力,揭示了新疆耕地变化的驱动机制,提出了新疆耕地可持续利用的措施建议。     

双孢蘑菇贮藏条件对其生理生化变化影响的研究进展

贮藏条件是影响双孢蘑菇贮藏效果的重要因素,介绍了气体成分、温度和湿度等因素对双孢蘑菇生理生化变化的影响。     

土地退化/恢复中土壤可蚀性动态变化

利用EPIC公式计算了不同开垦和退耕年限的土壤可蚀性K值,对黄土高原典型自然恢复区子午岭林区土地退化/恢复过程中土壤可蚀性的动态变化进行了系统的研究。结果表明：土地开垦后,土壤颗粒向粗骨化方向发展,有机碳含量降低,土壤可蚀性逐渐增强;土地退耕过程中,土壤有机碳含量逐渐增加,肥力水平提高,可蚀性逐渐减小;土壤中有机碳含量、全氮含量、水稳性团聚体含量以及团聚度与土壤可蚀性K值相关最为密切;土壤可蚀性的强弱本质上取决于土壤有机碳含量,恢复植被以提高土壤有机质含量,促进土壤团聚体的形成,增强土壤团聚度,是降低土壤可蚀性能的重要途径。     

花生根结线虫对节瓜苗期植株生长及主要生理特性的影响

对感染花生根结线虫的节瓜植株主要生理指标和生长量的变化进行测定。结果表明：花生根结线虫的侵染明显降低节瓜根系的活力,引起节瓜苗期植株的Ｎ,Ｐ,Ｋ和Ｍｇ含量显著下降,但对Ｃａ所吸收则有所增加;植株的叶绿素含量和光合速率均显著降低,但呼吸强度在线虫接种量为３０００和５０００条时则明显提高;植株生长的各项指标也发生不同程度的变化。     

吉林省生猪生产水足迹时空分异及优化布局研究

生猪养殖是畜牧业的重要组成部分,其生产和发展对水资源需求及水环境污染影响较大。水足迹区别于传统的取水指标,既可用于核算畜牧业耗水量,也可用于衡量畜牧业产生的水污染。为了研究吉林省生猪生产和发展对水资源需求及水环境的影响,基于水足迹理论及核算方法,对2000-2016年生猪生产水足迹进行量化,分析其绿水足迹、蓝水足迹、灰水足迹及总水足迹的时间变化和空间分布特征。结果表明：2000-2016年吉林省生猪的总水足迹呈下降趋势,其中绿水足迹呈上升趋势,蓝水足迹和灰水足迹呈下降趋势;吉林省各县(市、区)生猪绿水足迹、蓝水足迹、灰水足迹和总水足迹的空间分布总体为中部地区最高、东部地区最低,地域差异明显。因此,吉林省生猪养殖应优化布局,中部地区生猪养殖应大力发展,东部地区适当增加,而西部地区需加以控制。     

鲜食枣树体根部矿质元素含量的年动态变化

为了研究枣树根系年生长周期内矿质元素含量变化的情况,提高枣园的栽培管理技术,为科学合理的施肥提供一定的科学依据。对‘大白铃枣’、‘大瓜枣’、‘梨枣’、‘苹果枣’、‘晋矮3号’果实生长发育时期根系氮、磷、钾、钙、镁含量的变化规律进行研究。结果表明:植株生长初期,根系开始活动,活力不高,植株主要依靠体内贮藏营养物质来提供生长发育所需矿质元素,各枣品种大多数矿质元素的含量有不同程度地减少;植株生长中期通过根系从土壤中吸收大量矿质元素供新器官发育,根系中矿质元素变化较为复杂;在植株生长后期,大多数矿质元素均出现不同程度地增加并趋于稳定,开始为冬季休眠进行营养物质的贮藏。     

中式香肠自然晾挂成熟过程中微生物数量的变化规律

研究结果表明,在传统中式香肠自然晾挂成熟过程中,好氧菌总数、厌氧菌总数、嗜冷菌总数、酵母和霉菌总数从第1d至第12d逐渐上升,然后下降;乳酸菌总数从第1d至第8d逐渐增加,然后下降。     

马铃薯瓢虫幼虫感染绿僵菌后的组织病理变化

利用组织切片对马铃薯瓢虫幼虫感染绿僵菌后的组织病理变化进行了初步观察。结果表明:在相对湿度95%与25℃的温湿度组合条件下,幼虫体表附着的孢子萌发后穿透体壁,在体腔内逐步形成菌丝体,进入体腔内的菌丝体,对寄主组织没有选择性。通常菌丝最初在侵染部位的血腔中生长,然后侵入邻近的脂肪体、肌肉,最后侵入消化道和丝腺等。