元谋干热河谷冲沟形态特征及其成因

元谋干热河谷冲沟极为发育,发达的冲沟网络不但蚕食耕地,还产生大量泥沙,并加剧面蚀的发育发展,加速土地退化进程.在干热河谷开展冲沟侵蚀研究对于该区经济的可持续发展及江河泥沙的控制意义深远.采用野外实地调查、文献资料综合分析的方法,对元谋干热河谷冲沟形态特征及其成因进行了研究.结果表明:1)元谋干热河谷冲沟具有“沟壁陡立、沟谷深壑、活跃沟头常呈上凸下凹状”等形态特征;2)岩层结构、气候降雨、土壤属性是导致该区冲沟发育的主要原因.在此基础上指出,未来干热河谷冲沟侵蚀研究重点应集中于冲沟形态监测方法、冲沟发育过程及机制、冲沟产沙效应及人类活动对冲沟发育的影响等方面.     

Measured and modelled retention of inorganic sulfur in soils and subsoils (Harz Mountains,Germany)

Atmospheric deposition has resulted in an accumulation of inorganic sulfur (S) in many forest soils. At Sösemulde (Harz Mountains) samples from 5–240 cm depth were analysed. Most sulfate (SO₄) is accumulated at about 30–60 cm depth: 8.5–9.5 mmol_c kg^–1. Large amounts can also be retained in > 100 cm. To assess changes in SO₄ dynamics in time,adsorption isotherms have been included in several process-oriented models, e.g., in MAGIC. The Lange Bramke (LB) Model is the first model used on the catchment scale containing solubility products for the hydroxosulfate minerals jurbanite and alunite. By reconstructing the long-term acidification history (140 years) both models were successfully calibrated to a 14-year deposition, soil and streamwater data set at Lange Bramke catchment (Harz Mountains). According to MAGIC the present accumulation of SO₄ in 0 –80 cm is 8.7 mmol_c kg^–1, while according to the LB-Model 10.2 mmol_c kg^–1 are stored as jurbanite. Both models predicted 4.5 mmol_c kg^–1 SO₄ in the subsoil layer, retained as alunite in the LB Model. These values correspond to the amounts measured in soil and subsoil samples at Sösemulde, respectively. However, for future scenarios with decreasing S inputs the models show different developments in SO₄ concentrations. Changes in MAGIC are gradual whereas the LB model predicts stepwise decreasing SO₄ values as soon as previously stored hydroxosulfates are fully dissolved. Such concentration jumps have not been observed.     

Spatial Estimation of Soil Erosion Risk by Land‐cover Change in the Andes OF Southern Ecuador

Ecuador has the highest deforestation rate in South America, causing large‐scale soil erosion. Inter‐Andean watersheds are especially affected by a rapid increase of the population leading to the conversion of large areas of montane forest into pasture and cropland. In this study, we estimate soil erosion risk in a small mixed land‐use watershed in the southern Andes of Ecuador. Soil loss was estimated at a spatial resolution of 30 m, using the Revised Universal Soil Loss Equation (RUSLE) where the RUSLE factors were estimated on the basis of limited public available data. Land‐cover maps for 1976, 2008 and 2040 were created assuming increasing deforestation rates over the ensuing decades. Greater erosion rates are estimated for succession areas with agricultural cropland and pasture with maximum values of 936 Mg ha⁻¹ y⁻¹, where slopes and precipitation amounts are the greatest. Under natural forest vegetation, the estimated soil erosion rates are negligible (1·5 to 40 Mg ha⁻¹ y⁻¹) even at steep slopes and higher elevations where rainfall amounts and intensities are generally higher. When the entire watershed has undergone substantial deforestation in 2040, erosion values may reach 2,021 Mg ha⁻¹ y⁻¹. Vegetation cover is the most important factor for potential soil erosion. Secondary factors are related to rainfall (R‐factor) and topography (LS factors). Although the spatial predictions of potential soil erosion have only limited meaning for erosion risk, this method provides an important screening tool for land management and assessment of land‐cover change. Copyright © 2013 John Wiley & Sons, Ltd.     

CRISPR/Cas9基因编辑技术在植物中的应用与政策监管

基因编辑技术是一种在基因组水平上对DNA序列进行精准修饰,从而促使基因组序列定向改造的技术。随着近几年CRISPR/Cas9技术的快速发展,基因组编辑技术在作物育种领域发挥了越来越重要的作用。本文综述了基因编辑技术的发展历程,以及CRISPR/Cas9的工作原理,分析了CRISPR/Cas9的局限性并提出了改进方法。重点阐述了植物CRISPR/Cas9基因编辑体系的建立、在植物性状改良方面的应用,以及最终致力于基因编辑产品商业化的应用案例。同时还分析了美国、欧盟、英国、日本和中国这5个代表性国家/地区的基因编辑监管政策和态度,以期为我国科学监管框架的建立提供参考,促进CRISPR/Cas9在我国乃至全球的产业化应用。     

基于CNKI的山东省农科院科技论文计量分析

采用文献统计分析方法,利用CNKI文献计量分析工具,分析山东省农业科学院发表的论文情况,包括年度、作者、学科分布、项目资助来源、期刊、关键词以及论文被引频次等指标,以期为山东省农科院的科学研究总结经验、提供发展规划依据。     

新中国50年土地（利用）规划的回顾与展望

1954年,土地规划作为一门科学引入我国,1956年在东北农学院开设了我国第一个土地规划专业,此后在一些大学曾开过土地规划课程。改革开放前,土地规划属于工程技术类,规划的重点是农用土地的勘测和土地规划设计与实施。改革开放后,“土地规划”改称为“土地利用规划”属于经济管理类,土地利用规划发展内容拓展,土地利用方法向规划的模型化和信息化方向发展。土地利用规划在实践中也表现出诸多问题,基础理论尚不完善,规划的目标、体系、方法等缺少科学性,规划编制和实施过程缺乏规范化和法制化,规划人员素质不高,技术落后等。在未来的发展进程中,可持续发展的土地利用规划将成为普遍共识,土地利用规划将逐步完善体系建设,建立土地利用规划的实施保障体系,搞好土地利用规划编制的基础工作,提高科学性和标准化水平。     

定陶县近40年气候变化特征与成因探析

本文选用定陶气象站1971～2010年地面观测资料,对气温、降水、日照等气候要素变化特征及成因进行分析、探究。结果表明:(1)80年代为低温期,90年代为升温期,2001～2010年为高温期;年平均气温以0.232℃/10a的倾向率波动上升;气温日较差有变小的趋势;年平均最低与冬季气温的上升对气候变暖贡献显著;冷空气活动对气温上升起到减缓或助长的作用。(2)1981～1990年为少雨年代,2001～2010年为多雨年代;年降水量的倾向率为13.454 mm/10a,未来有振荡性增多的趋势;旱涝灾情有阶段性,1993～2005年明显加重;厄尔尼诺(El Nino)事件与当地异常降水相关性较好。(3)年日照时数随年代减少,倾向率为-135.21 h/10a;夏秋两季日照时数的气候倾向决定着年日照时数的总体趋势;降水量与云量对日照时数减少起到一定的促进或制约的作用,不决定其总体趋势。     

中国水稻植保机械现状与发展趋势

植保作业是水稻生产过程中必不可少的环节,提高水稻植保机械化水平,对降低稻田农药的用量,增强突发性爆发性病虫害防控能力,缓解农村劳动力短缺,实现农业可持续发展具有重要意义。从目前常见的人力施药器械入手,对水稻生产中的小型动力植保机械尧大中型动力植保机械和航空植保机械的应用现状及存在问题进行了详细阐述。在分析中国水稻植保机械发展现状的基础上,探讨了现代农业生产中对研究开发用于稻田农药高效精确喷施新方法和新工具的迫切需求,指出未来水稻植保机械主要朝着精准施药和高效施药两个方向发展。最后,从拓宽单次喷施作业的覆盖范围、加强稻田农药喷施作业方法创新和大力推进航空植保技术的应用等方面给出了促进我国水稻植保机械化进一步发展的建议。     

中国高粱产业和种业发展现状与未来展望

高粱是全球第五大粮食作物,也是中国重要的杂粮作物。国家启动产业技术体系10年来,鉴定和创制出277份矮秆、抗病、高支链淀粉、低单宁的育种材料;利用突变体、自然群体全基因组关联分析克隆了高粱重要性状的控制基因;育成了71个矮秆耐密、适宜机械化作业的酿造专用高粱新品种,创新集成适合不同区域高粱轻简栽培技术,全国高粱种植面积增长26.8%,总产增长93.5%,单产提高52.7%,实现了高粱生产方式全面机械化的重大变革。在高端白酒转型升级的拉动下,以茅台、五粮液、汾酒等知名酒企为核心,形成了以"品牌+品种+产地+农户"高粱特色产业发展模式并取得了显著的增收效果。产业发展助推品种权保护与转让,面向产业与企业需求的联合育种与产业化开发带动高粱种业起步发展。在乡村振兴战略和健康中国战略新的时代背景下,高粱的抗旱、耐涝、耐盐碱、粮饲兼用、高光效等特性给中国高粱产业和种业发展带来了新的机遇;同时中国高粱种业和产业也面临着多用途开发不足、品种权保护力度不够、原始性创新能力有待加强、产业政策支撑不足等诸多挑战。未来中国高粱新品种选育和种业由酿造为主向多用途转变,针对企业酿造工艺需求对不同适宜地理环境开展定向...     

Numerical modeling of environmental behavior and fate of tributyltin in a semi-closed bay

The environmental behavior and fate of tributyltin (TBT) in the northern Ariake Sea, resulting from the use of TBT-containing antifouling paints on hulls of ships, pleasure crafts and docking facilities, was assessed by numerical simulations. First, a mathematical model was devised on the basis of a non-steady state equilibrium, one box multi-compartment model consisting of the surface micro-layer, the water column, the mud-layer, and the bottom sediment compartments. The movement of TBT among the four compartments was modeled by resuspension of bottom mud, deposition of suspended sediment, film penetration and water advection in each compartment. Furthermore, a one-dimensional diffusion equation was introduced into the bottom sediment compartment to calculate profile distribution of TBT. The reactivity of TBT considered within the compartments included biological degradation, adsorption to particulate matter and diffusion. Next, the optimal amount of past TBT loads, reflecting the recent observations of TBT concentration in the waters and sediments of the northern Ariake Sea, was searched by a simple genetic algorithm. The relative sensitivity of various model parameters were also determined to identify the more important parameters for estimating the environmental behavior and fate of TBT. Finally, the future status of TBT contamination of the northern Ariake Sea was predicted assuming the discontinued use of TBT-containing antifouling paints. Despite its simple model structure relative to hydraulics, it was concluded that this multi-compartment model adequately estimated the environmental behavior and fate of TBT.