桑园专用杀虫剂的田间药效筛选及家蚕残毒试验

[目的]筛选出对桑园害虫防治效果好,桑叶残毒对家蚕影响小的杀虫剂。[方法]采用室内毒力测定、田间药效试验、农药残留速测以及残毒测定相结合的方法进行试验。[结果]室内毒力测定结果表明,桑树1号对桃粉绿芽的LC50为（316.1±57.3）mg/kg,桑树1号在药后14d,防效达62.58%;药后7d的农药残留速测显示可安全饲育家蚕,达到用叶标准。[结论]推荐桑树1号作为桑园专用杀虫剂使用。     

覆土厚度对冬种马铃薯还田稻草腐解进程的影响

[目的]为了探讨广东冬种马铃薯主产区覆盖还田稻草的腐解进程。[方法]采用尼龙网袋法,研究水稻稻草在不同覆土深度（0、5.0、7.5和10.0 cm）对还田稻草腐解的影响。[结果]覆土深度为7.5 cm时腐解速度最快,覆土深度0 cm最慢。还田60 d后,覆土深度7.5 cm的稻草残留率为50%,而覆土深度0 cm的稻草残留率为80%。稻草还田后有机碳在前10 d分解较快,稻草的全碳含量随着还田时间延长而逐渐下降,导致C/N比降低。冬马铃薯收获时覆土深度0 cm有机碳残留率为76%,覆土深度7.5、10.0和5.0 cm的有机碳残留率依次为69.3%、70.8%和72.5%。还田的前10 d稻草氮素含量呈现上升趋势,20 d后才出现下降趋势。一季马铃薯田稻草还田后稻草有机碳只释放了1/3左右。[结论]稻草还田前期可以固定部分氮素,还田后期会释放一定的氮素供马铃薯生长需要。种植一季马铃薯作物后,还田的稻草并没有被完全腐解。     

吡蚜酮在水稻中的残留动态研究

[目的]了解吡蚜酮在水稻植株中的残留动态以及在收获期水稻中的最终残留量。[方法]通过田间试验和高效液相色谱分析技术,研究了25%吡蚜酮可湿性粉剂在水稻植株中的消解动态以及在收获期水稻中的最终残留量。[结果]吡蚜酮在水稻植株中的降解半衰期为0.51～0.53 d,符合一级化学反应动力学方程。在水稻生长期喷施1次,按推荐剂量300 g/hm2和2倍剂量600 g/hm2施用25%吡蚜酮可湿性粉剂,在收获期植株、糙米和稻壳中均未检出。[结论]吡蚜酮属于易降解农药（T1/2〈30 d）。在水稻田使用25%吡蚜酮可湿性粉剂时,按推荐剂量300 g/hm2施药1次,建议水稻上最大残留限量值暂定为0.02 mg/kg。     

既有居住建筑节能改造优化的思路

对既有居住建筑进行节能改造具有重大的社会意义与环保价值。既有居住建筑的现状有着较大的差异,在节能改造时应根据建筑物的剩余使用年限、结构类型提出不同的节能目标,利用节能设计软件进行辅助设计,通过多方案节能效果与经济性的比较提出最优的节能改造方案。优化节能改造方案使得既有居住建筑节能改造具有较好的经济性,研究成果为建筑节能改造拓展了新思路。     

基于数据包络分析方法（DEA）的农业信息化贡献实证分析

结合数据包络分析方法中C2R模型,建立了测算农业信息化对农业生产贡献率的数学模型。并以浙江省为例,测算了农业信息化对浙江省农业生产的贡献率,采取定性分析与定量分析相结合的方法,对测算结果进行全面、系统的分析。     

Within and between-field spatial variation in soil phosphorus in permanent grassland

Soil phosphorus (P) concentrations above certain critical thresholds are a problem in many areas leading to its transport into surface and ground waters. Site-specific nutrient applications and the development of nutrient management plans for farms would help to optimize nutrient applications, meet crop requirements and take into consideration current soil nutrient status. In Northern Ireland, high concentrations of soil P are common, whereas low concentrations of soil potassium (K) and sulphur (S) have been reported in many silage fields. This study used grid and transect soil sampling to measure within- and between-field spatial variation in soil Olsen-P status across a 50-ha permanent grassland site used for silage production. Soil phosphorus indices ranged from Index 1 to Index 4 within single fields. The spatial patterns of soil P across fields suggested that there was scope for site-specific P fertilizer applications, with variable quantities of P being applied to different fields and within individual fields. Site-specific nutrient management has the potential to reduce excess P applications in some areas and avoid deficiencies in others, thereby minimizing environmental problems and optimizing yield.     

铅和镉暴露后蛋鸡组织中铅和镉的残留规律

[目的]探讨铅和镉联合暴露后蛋鸡各组织器官中铅和镉的残留规律。[方法]将120只40周龄海兰褐壳蛋鸡随机分为4组,对照组饮用纯净水,Cd暴露组在饮水中添加50 mg/L Cd,Pb暴露组在饮水中添加100 mg/L Pb,Pb+Cd暴露组在饮水中添加100 mg/L Pb和50 mg/L Cd,探讨蛋鸡各组织器官中铅和镉的残留规律。[结果]与Cd暴露组相比,Pb+Cd暴露组除肾脏外各组织中的镉含量均有升高,但差异不显著(P0.05);Cd暴露组肾脏中镉含量显著高于Pb+Cd暴露组。与Pb暴露组相比,Pb+Cd暴露组胸肌和肾脏中铅含量显著降低(P0.05),而腿肌、心脏、脾脏中铅含量显著升高(P0.05),肝脏和肌胃中铅含量则基本相当。与对照组相比,Pb暴露组各组织中的镉含量显著升高(P0.05),而Cd暴露组蛋鸡各组织中铅含量差异不显著。[结论]铅和镉在家禽体内沉积存在复杂的交互作用。该研究可为促进禽产品质量安全提供理论基础。     

旱地土壤中残留肥料氮的动向及作物有效性

氮素是作物生长最重要的必需元素之一。合理施用氮肥能促进作物生长并提高产量,但是,过多施用氮肥则抑制作物生长并导致大量的肥料氮残留在土壤中,这部分氮素不但会引起土壤养分不平衡,而且为生态环境带来潜在威胁,因此,研究残留氮的动向及作物有效性可为合理施用化肥氮、高效利用土壤残留氮素和减少残留氮素的损失提供依据。应用~(15)N示踪技术,通过4年定位试验,研究了黄土高原南部旱地冬小麦/夏玉米轮作过程中土壤残留肥料氮的变化及作物吸收利用。在冬小麦和夏玉米轮作的第一个周期,为了制造高肥料氮残留背景,于冬小麦播种前向微区施入240 kg hm~(-2)的~(15)N标记氮素;在夏玉米拔节期,为了研究氮肥施入对残留肥料氮的影响,设置0和120 kg hm~(-2)两个氮水平,以普通尿素施入微区。在第2至第4个轮作周期内,为了分析残留肥料氮的动向及其对作物的有效性,微区内不施任何肥料。结果发现,冬小麦播种前施用的~(15)N标记氮肥于收获期在0~200 cm土壤剖面中均有残留,但大部分累积在0~40 cm土层中,累积总量达到200.9 kg hm~(-2),占当季施入量的83.7%。在随后的夏玉米生长季残留的肥料氮迅速减少,之后随生长季的后移缓慢减少,然后保持相对稳定。经过4年的冬小麦/夏玉米轮作,0~300 cm土壤剖面仍残留大量的~(15)N肥料,后季不追施氮肥和追施氮肥处理的残留量分别为47.1 kg hm~(-2)和54.0 kg hm~(-2)。可见,有一部分肥料氮被固定在土壤有机质中。作物对残留氮的回收量逐年减少,且因后季追施氮肥与否而异,4年中作物对肥料氮的总利用率不追施氮肥和追施氮肥处理的分别为46.9%和50.4%,其中在第1个轮作周期中,小麦和玉米的总利用率分别41.6%和42.0%,后3年利用率分别仅有5.3%和8.4%;4年中残留~(15)N的损失率分别达38.1%和29.7%,其损失主要发生在第1个轮作周期的夏玉米生长季节。说明,在旱地土壤上,氮肥的残留是不可避免的,残留肥料氮的有效性较低,只有少量被作物逐年吸收,一部分以有机形态残留在土壤剖面中,另一部分发生了无效损失。后季追施氮肥可促进作物对土壤残留肥料氮的吸收且增加肥料氮在土壤中的保留,减少残留肥料氮的无效损失,但是以自身的大量损失为代价的。     

Landscape-scale disturbance and boreal forest birds: Can large single-pass harvest approximate fires?

Boreal forest birds have adapted to changes caused by natural disturbances such as fire and this adaptation forms the basis for the Natural Disturbance Paradigm (NDP) underlying recent proposed changes in forest harvesting practices in western Canada. To date, this paradigm has been evaluated primarily at the stand level and within conventional harvesting systems. The potential for improvements in avian conservation at the landscape scale by adopting the NDP approach is largely unknown. We examined the effects of landscape-scale disturbances on forest bird communities by contrasting richness and abundance of birds in (1) 16 single-pass harvest sites with residual forest patches, (2) 29 multi-pass harvest sites with residuals; and (3) 15 salvage-logged post-fire sites with variable harvest intensity. We contrasted bird communities in these treatments with those in unsalvaged post-fire sites of similar age. Post-fire sites were used to provide a metric of the Natural Range of Variation (NRV) to be expected in bird communities. Sites were surveyed for avian community composition and abundance 1–5 years post-disturbance. Redundancy analysis indicated that bird communities differed from the NRV in all of the harvest treatments. However, single-pass harvests provided a somewhat better fit to NRV than did multi-pass harvesting. Avian community similarity was influenced by non-linear responses to area harvested, amount of residual retention, residual composition and pre-disturbance forest composition. An optimization routine created from a General Linear Model, suggests that community similarity to NRV can be maximized by using single-pass harvests over multi-pass harvests, harvesting 66–88% of the timber in the planning unit, and retaining 5–19% of the disturbance area as live residual patches, with 50% of harvests having at least 9% of the area in residuals.     

水稻第6染色体短臂产量性状QTL簇的分解

【目的】将水稻第6染色体短臂上产量性状QTL分解到更小的区间中。【方法】从珍汕97B/密阳46重组自交系群体筛选到针对第6染色体短臂RM587-RM19784区间的剩余杂合体,衍生了一个由221个株系组成的F2:3群体,种植于海南和浙江两地,考察每株穗数、每穗实粒数、每穗总粒数、千粒重、结实率和单株产量,建立SSR标记连锁图,应用Windows QTL Cartographer 2.5检测QTL。【结果】在所分析的6个性状中,除穗数外在第6染色体短臂上的目标区间均检测到QTL,分别座落于目标区域中3个以上的不同区间中,单个QTL对群体性状表型变异的贡献率为6.3%～35.2%;控制产量构成因子的QTL基本以加性作用为主,但3个单株产量QTL的显性度分别为1.65、0.84和0.42。【结论】目标区间存在3个以上的产量性状QTL,且同一区间控制不同性状的QTL、不同区间控制同一个性状的QTL在遗传作用模式、效应方向和效应大小上存在一定差异。