柳杉花粉的散发规律

柳杉花粉囊为纵向开裂，雄球花在雨季对花粉具有保护功能；雌雄球花和花粉都对风媒传播发生了适庆性变化；花粉的散发，传播，沉降和空间分布，出现规律性变化，并受降水，气温，风力和大气湿度的综合影响。针对花粉散发特性，提出了经营种子园的有关建议。     

An evaluation of the Olsen test as a measure of plant-available phosphorus in grassland soils derived from basalt parent material

Abstract. Anecdotal and circumstantial evidence have suggested that the Olsen test underestimates plant-available phosphorus (P) in basaltic soils in Northern Ireland. Therefore, the ability of this test to predict plant-available P in basaltic (and non-basaltic) soils was investigated by regressing Olsen-P data against herbage P indices calculated from plant tissue test data using the diagnosis and recommendation integrated system. The average Olsen-P concentration for a range of fields situated on basaltic soils was considerably lower than the average Olsen-P concentration for a range of fields situated on non-basaltic soils, and yet mean sward P status, as given by the herbage P indices, was similar for both groups of fields. Herbage P indices were also much better correlated with Olsen-P measurements in non-basaltic soils than in basaltic soils. Furthermore, at low Olsen-P values (≶9mgPL⁻¹) some swards on basaltic soils were genuinely deficient in P, while others were sufficient or even in surplus for this nutrient. The results confirm that Olsen-P is inadequate as a predictor of plant-available P in basaltic soils. It is concluded that an alternative soil test is needed to provide a reliable assessment of plant-available P in basaltic soils, to prevent overuse of fertilizer and manure P and to minimize the amounts of P entering local watercourses.     

Evaluation of two N cycle models for the prediction of N mineralization from grassland soils in the UK

Abstract. The ability of two nitrogen cycle models, of contrasting complexity, to predict N mineralization from a range of grassland soils in the UK, was evaluated. These were NCYCLE, a simple mass balance model of the N cycle in UK grasslands, and CENTURY, a more complex model simulating long-term C, N, P & S dynamics in grassland ecosystems. The models were tested using field measurements of net N mineralization from a range of grassland soils (differing in soil type, history & management practice), obtained over a 2 year period using a soil core incubation technique. This method was considered to measure the total net release of mineral N from the soil organic matter over a specified time, including N which may have been recycled several times. NCYCLE consistently under-estimated mineralization rates at all sites. By contrast, there was some correlation between CENTURY predictions of net N mineralization and field measurements. This may have reflected the different abilities of the two models to simulate N recycling. Neither model, however, was able to predict adequately the effect of cultivation and reseeding on net N mineralization.     

The use of urban organic wastes in the control of erosion in a semiarid Mediterranean soil

Abstract. A two year field experiment was carried out in a semiarid Mediterranean area in order to evaluate, the effect on soil erosion of adding different urban organic wastes: a stabilized municipal waste (compost), an unstabilized municipal waste, and an aerobic sewage sludge. All the treatments significantly reduced soil erosion, compared to the control soil. The soil amended with compost was the most effective treatment, reducing soil loss by 94% and runoff by 54%.     

Effects of 'Agri-SC' soil conditioner on soil structure and erodibility: some further observations

Abstract. In field and laboratory experiments the conditioner‘Agri-SC’has shown improvements in the structure of loamy sand soils in east Shropshire, UK. It resulted in statistically significant decreases in soil bulk density values and increases in soil porosity and aggregate stability. Further experiments are in progress on both loamy sand and silt loam soils.     

糯米糍荔枝果实内源激素与落果的关系

以糯米糍荔枝生理落果期的田间调查和胚胎发育研究为基础,探讨了内源激素与生理落果的关系.结果表明,糯米糍生理落果高峰的主要原因是:第1次因授粉受精不良导致的生长促进类激素尤其是CTK水平过低;第2次与胚乳为胚的发育所利用而消失、IAA和GAs急剧降低有关;第3次与胚的败育造成CTK、GAs和IAA的全面下降有关;第4次发生在假种皮(果肉)迅速生长期,与种皮和假种皮ABA升至高水平有关.此外,还探讨了ABA /(IAA+GAs+CTK)与生理落果的相关性,以及胚囊、珠被和假种皮等果实内部组分内源激素的变化特点.     

不同熟期荔枝品种的枝梢生长节奏的初步研究

本试验以3-4年生的早熟（‘三月红’）、中熟（‘妃子笑’）、晚熟（‘糯米糍’）及特迟熟（‘马贵荔’）荔枝品种为试材,比较不同成熟期荔枝品种周年的枝梢生长节奏及新叶发育过程中叶绿素指（SPAD）数动态。结果表明：各品种枝梢伸长生长具有一定差异,但都具有一定的节奏性,而枝梢增粗生长周年持续进行,无明显节奏特征;叶绿素指数达到最高值的80%时增加缓慢,因此叶绿素指数达最高值的80%时作为枝梢成熟的标准,用来确定枝梢成熟的时间。     

Interactions between phosphorus availability and microbes in a wheat–maize double cropping system: A reduced fertilization scheme

Mechanisms controlling phosphorus(P) availability and the roles of microorganisms in the efficient utilization of soil P in the wheat–maize double cropping system are poorly understood. In the present study, we conducted a pot experiment for four consecutive wheat–maize seasons(2016–2018) using calcareous soils with high(30.36 mg kg^–1) and low(9.78 mg kg^–1) initial Olsen-P content to evaluate the effects of conventional P fertilizer application to both wheat and maize(Pwm) ...     

外源腐胺对糯米糍荔枝座果的影响

试验研究了腐胺（Put）在不同时期、不同浓度和不同次数喷施对糯米糍荔枝座果的影响。结果表明，以盛花期喷施30－40mg/L的座腐胺1次，对提高糯米糍荔枝的座果率效果最好，而对果实体积和单果重没有明显影响。     

山西省苹果园山楂叶螨对5种杀虫剂抗药性监测

为了明确山西省苹果园山楂叶螨(Amphitetranychus viennensis Zacher)对化学杀虫剂的抗性现状及发展趋势,本文采用玻片浸渍法建立了山楂叶螨相对敏感种群对5种杀虫剂的敏感基线,连续3年(2013-2015年)监测了采自山西省苹果主产区运城苹果园的山楂叶螨对5种杀虫剂的抗性水平及变化动态。监测结果表明:田间监测种群对阿维菌素和三唑锡均处于敏感性下降及低水平抗性阶段,对哒螨灵和噻螨酮的抗性由低水平抗性升至中等水平抗性,对炔螨特处于低水平抗性。田间防治山楂叶螨时,哒螨灵与噻螨酮应淘汰不再使用,阿维菌素、三唑锡、炔螨特则应注意减少用药量及轮换用药,以延缓产生更高水平的抗药性。