大通县长宁镇退耕还林(草)后续产业探讨

分析了退耕还林(草)现状,结果表明,退耕还林草的后续产业发展不足,提出发展退耕还林草的后续产业对策。     

规划衔接与建设用地空间管制协调研究

在前人研究的基础上,总结了上一轮土地利用规划实施过程中存在的问题,研究规划衔接的重要性和必要性。从剖析比较各类规划,特别是土地利用总体规划和城乡规划的内容和侧重点差异性的基础上,提出规划衔接的可行性及方法,探讨了规划衔接与建设用地空间管制的主要内容及协调对策,提出了对相关研究和新一轮规划编制的建议。     

农村土地违规建房问题研究

土地作为一种不可再生资源,同时又是人类赖以生存的生产生活资料,应该得到人类的珍惜和保护.但随着我国新农村建设的不断发展,农村土地违规建房问题也凸显出来.通过分析我国农村土地违规建房的根源、现状,梳理出治理违规建房的有效对策,以期为解决农村土地违规建房问题提供一些新思路.     

Estimation of phenotypic variability in symbiotic nitrogen fixation ability of common bean under drought stress using 15N natural abundance in grain

Common bean (Phaseolus vulgaris L.) is the most important food legume, cultivated by small farmers and is usually exposed to unfavorable conditions with minimum use of inputs. Drought and low soil fertility, especially phosphorus and nitrogen (N) deficiencies, are major limitations to bean yield in smallholder systems. Beans can derive part of their required N from the atmosphere through symbiotic nitrogen fixation (SNF). Drought stress severely limits SNF ability of plants. The main objectives of this study were to: (i) test and validate the use of ¹⁵N natural abundance in grain to quantify phenotypic differences in SNF ability for its implementation in breeding programs of common bean with bush growth habit aiming to improve SNF, and (ii) quantify phenotypic differences in SNF under drought to identify superior genotypes that could serve as parents. Field studies were conducted at CIAT-Palmira, Colombia using a set of 36 bean genotypes belonging to the Middle American gene pool for evaluation in two seasons with two levels of water supply (irrigated and drought stress). We used ¹⁵N natural abundance method to compare SNF ability estimated from shoot tissue sampled at mid-pod filling growth stage vs. grain tissue sampled at harvest. Our results showed positive and significant correlation between nitrogen derived from the atmosphere (%Ndfa) estimated using shoot tissue at mid-pod filling and %Ndfa estimated using grain tissue at harvest. Both methods showed phenotypic variability in SNF ability under both drought and irrigated conditions and a significant reduction in SNF ability was observed under drought stress. We suggest that the method of estimating Ndfa using grain tissue (Ndfa-G) could be applied in bean breeding programs to improve SNF ability. Using this method of Ndfa-G, we identified four bean lines (RCB 593, SEA 15, NCB 226 and BFS 29) that combine greater SNF ability with greater grain yield under drought stress and these could serve as potential parents to further improve SNF ability of common bean.     

基于社会燃烧理论的耕地非农化驱动因素分析

中国耕地非农化现象日益明显。基于社会燃烧理论分析了耕地非农化的驱动原理,建立了耕地非农化影响机制模型,并运用SPSS 19.0软件对分类驱动因素进行了主成分及回归分析。结果表明,人均GDP和固定资产投资所占GDP比重等经济发展变量对耕地非农化水平的正向影响最大;粮食单产、总产等农业技术变量对耕地非农化水平具有最大的逆向影响。最后在模型拟合的基础上提出了相应的对策与建议,旨在为合理有效保护耕地提供参考。     

太原经济技术开发区用地效益评价

通过对太原经济技术开发区的实际调查和对2002—2011年10 a间的相关统计及国家商务部历年发布的国家级经济技术开发区发展报告的信息进行分析,从开发区土地利用现状、年度建设用地供给、科工贸收入、工业总产值、GDP、税收收入、国内外资金利用等方面,综合评价了太原经济技术开发区的经济效益和用地效益。结果表明,该区独立运行10 a来成绩显著,整体效益逐步提高,在山西所有开发区中经济效益名列前茅,在全省经济技术开发区中每年的综合评价都名列第1;与国内中西部或中部的同类开发区相比,该区经济总量和单位面积产生的效益排名中后;与国内先进经济技术开发区相比,差距较大;该区内部分企业规模大、影响广泛,经济效益和用地效益均好,起到了带头和示范作用,但仍有部分企业规模小、投入水平低、建设周期长、产生效益低,影响了全区整体效益的发挥。建议开发区管委会引导入区企业加大投入,加快建设步伐,及早产生经济效益;尽快实施扩区计划,保证经济快速、健康发展;落实土地供给和退出政策,使有限的土地发挥更大的效益。     

Identification of the core motif of the BRCA2 C-terminal RAD51-binding domain by comparing canine and human BRCA2

Mammary tumors are the most common tumors in women and non-spayed female dogs. One of the reasons for mammary tumors is mutations of the tumor suppressor gene, BRCA2. BRCA2 participates in homologous recombination repair by interacting with the RAD51 recombinase. BRCA2 has two RAD51-binding domains, consisting of BRC repeats and the C-terminal RAD51-binding domain, respectively. Although several studies have addressed the function of the C-terminal RAD51-binding domain of human BRCA2, the amino acid sequences required for the RAD51-interaction activity remain unclear. In this study, the C-terminal RAD51-binding domains of canine and human BRCA2 were compared; the canine domain displayed a weaker interaction with RAD51. This difference was attributed to the C-terminal portion of the domain via a comparison between canine and human domains. Furthermore, peptides shorter than those previously reported displayed RAD51-interacting activity, and a core motif of this domain consisting of 25 amino acids was identified. Since a mutation (S3323N) was reported in the core motif of this domain, the effect of this mutation was evaluated. The mutant exhibited similar RAD51-binding activity as that of the wild-type protein, suggesting that the mutation was functionally neutral. These data suggested that the C-terminal portion of the BRCA2 C-terminal RAD51-binding domain influenced its RAD51-interaction activity, and a minimum core motif of 25 amino acids was identified in this domain. These data may help clarify BRCA2 function, as well as the tumorigenic effects of BRCA2 mutation.     

培肥措施对旱地农田土壤CO2排放和碳库管理指数的影响

阐明长期有机物料施肥下土壤CO₂排放特征及其影响机制以及碳库管理指数对黄土高原旱作农业区固碳减排及施肥模式选择的影响尤为重要。基于2012年设置在陇中黄土高原旱作区的长期定位试验,通过不施肥（CK）、氮肥（NF）、有机肥（OM）、秸秆（ST）、有机肥结合无机肥（OMNF）5个处理,测定并计算了2018年不同施肥措施下全年土壤CO₂排放、作物碳排放效率和碳库管理指数的变化,并运用结构方程模型分析了0~30 cm土壤温度、水分、微生物量碳氮、易氧化有机碳、蔗糖酶、脲酶与土壤CO₂排放速率的关系。结果表明：1）与不施肥相比,秸秆、有机结合无机肥和有机肥处理使生育期土壤CO₂排放平均速率提高了42.72%、30.82%和29.79%,秸秆、有机肥处理分别使生育期土壤CO₂排放量显著提高36.35%、32.45%（P<0.05）,有机结合无机肥处理使碳排放效率显著降低41.10%（P<0.05）;2）有机物料处理均能显著提高0~5 cm土层易氧化有机碳、微生物量碳氮、蔗糖酶活性和碳库管理指数,相比不施肥和氮肥处理,有机结合无机肥处理分别使0~30 cm土壤碳库管理指数提高127.41%,99.33%（P<0.05）;3）结构方程模型表明,环境因子对土壤CO₂排放速率的总解释度为53%,对土壤CO₂排放速率总效应较大的影响因素包括土壤温度（2.36）、微生物量碳（1.59）和土壤水分（1.18）,且均间接地影响着土壤CO₂排放速率,土壤温度促进了微生物量碳和蔗糖酶活性的提高,微生物量碳促进了微生物量氮和易氧化有机碳的增加。综合来看,有机结合无机肥处理可以提升土壤碳库管理指数,保持微生物活性,增加作物产量,降低土壤碳排放效率,是陇中黄土高原旱作农业区比较适宜的农田培肥措施。     

宁夏回族自治区养殖粪污资源化利用现状调查与分析

畜禽粪污资源化利用,是农村生态环境保护工作的重点和难点,对于改善农村生态环境质量、提高农业绿色发展水平、促进农产品增产提质具有重要意义。本文为进一步了解宁夏回族自治区（简称“宁夏”）畜禽粪污资源化利用现状,在宁夏银川市、石嘴山市、吴忠市、中卫市、固原市5 市,对四大产业主导区畜禽养殖产业基本情况、全区及各市不同类型和规模的畜禽养殖粪污资源化利用现状及问题、不同养殖类型和规模的资源化主推技术及典型案例等情况进行了实地调研。结果表明：2020年,宁夏畜禽存栏总量2 046.0 万头（只）,其中,奶牛57.4 万头、肉牛120.7 万头、羊596.1 万只、生猪90.0 万头、家禽1 181.8 万只。畜禽粪污产生量3 025.3 万吨,全区粪污资源化利用总量为2 961.6 万吨,综合利用率达到97.9%,规模养殖场设施配套率达99.0%,该地区畜禽粪污综合利用主要途径有肥料化利用、能源化利用、清洁再生回用等。