A comparison of yield and its components between hybrid rice and conventional rice varieties was made with different seedling quantity and row spacing at transplanting.Compared with conventional rice,hybrid rice combinations had much larger panicles,heavier 1000-grain weight,higher economic index,longer duration of grain filling,higher percentage of assimilate distribution to grain,resulting in an average yield increase of 7.27 percent.Single seedling per hill planting was suitable for hybrid rice combinmations,while three seedlings per hill planting for conventional rice varieties.No matter hybrid rice or conventional rice varieties,erect and semi-erect panicle rice varieties were suitable for equal row spacing cultivation for intercepting more light at canopy,while curved-panicle rice varieties were for wide-narrow row spacing cultivation for improving light intensities of middle and lower layer leaves.

烟台继2002年4月24～25日发生严重"倒春寒"现象后,2004年4月23～24日凌晨、26～27日凌晨,又发生2次大规模霜冻,多数地区最低气温均达零下,招远等地最低气温达到-3.6℃,致使正处幼果期的桃、梨、杏、李子、苹果以及初现花序的葡萄等受到不同程度的冻害,给果树生产带来重大损失,预计总减产为20%左右.为了今后能有效地预防晚霜冻害,笔者对这次晚霜冻害进行了调查,并提出了预防和补救的措施.

农药的效力和防治效果是众所周知的,据联合国粮农组织1998年统计:世界谷物生产每年因虫害损失14%,因病害损失10%,因草害损失11%.农药以其快速简便和价格低廉的特点在农业的增产保收中起着巨大的作用,而由于缺乏这一手段使农业生产因病虫草所酿造成的悲剧,人们至今记忆忧新:1845年由于马铃薯晚疫病大流行所形成的震惊世界的爱尔兰大饥慌;1870～1880年间由于葡萄霜霉病大流行导致法国葡萄种植业的崩溃和葡萄酿造业的倒闭.

在水浇地高产麦田研究了施氮量对强筋小麦籽粒产量和品质的影响.结果表明,适当增加氮肥施用量可以提高各产量构成因素的水平,因而产量增加,过量施用氮肥虽可以增加公顷穗数,但穗粒数和千粒重下降,而导致产量降低.增加氮肥的施用量能够改善强筋小麦的营养品质和加工品质,但随着施氮量的增加改善的幅度降低.综合施氮量对小麦产量及构成因素和品质性状的影响效应,认为在较高土壤肥力的麦田适宜施氮量为240kg/hm2左右.

The effects of different proportion of basal nitrogen and topdressing nitrogen on grain quality and yield of strong gluten wheat variety jinan 17 are studied in the article. The results show, properly augmenting the topdressing nitrogen proportion on jointing stage can remarkably increase the number of the spikes per 667m2?the number of the kernels per spike and the weight of thousand kernels to enhance the wheat yield and can improve the qualitative character, integrating the yield and the quality, we think it is proper to make 1/2 of the total nitrogen as basal fertilizer and 1/2 as topdressing fertilizer or 1/3 as basal fertilizer and 2/3 as topdressing fertilizer.

波尔多液是无固定成品、现用现配制为不同规格的药液。呈天蓝色胶态悬浮液，是优良的保护性杀菌剂，应在发病以前喷洒，是生产无公害果品的首选农药。 1 波尔多液的配制方法 一般采用“两液同时倾倒法”配制。以1：2：250倍石灰倍量式波尔多液为例：如配制250kg……

The growth characteristics of Digitaria sanguinalis(D.s) was investi-gated under both fields and a greenhouse conditions. The results showed that the seed had a relative short dormancy. The suitable covering soilsickneen for seed emerging was 0.5～4.0cm. As the density being increased and the daley of emerging time the growth of a single plant of D.s was reduced.

通过4年田间试验,探索出大豆田除草剂甲草胺、异丙甲草胺及普乐宝的除草效果,结果表明: 这3种除草剂的最适用量分别为3.00L/hm2、1.80L/hm2、1.65L/hm2,对大豆高度安全,一次使用可防除大豆全生育期的杂草危害,大豆产量增产显著.

系统调查了萝卜、白菜、甘蓝、油菜花、苔菜田桃蚜种群随时序的数量变化,采用模糊聚类方法将其田间数量动态分为6个时期,即:迁入期、初发期、扩散期、种群增长期、盛发期和衰退期.防治适期应该掌握在初发期至种群增长期的初级阶段.