Biomass and production of fine roots in Japanese forests

To better understand the control of fine-root dynamics in Japanese forests, we reviewed studies conducted in Japan on fine-root biomass and production. Most of the data on fine-root biomass were obtained for conifer plantations in limited regions; the average fine-root biomass of dominant trees ranged from ∼50 g m₋₂ for Pinus species (n = 3) to ∼600 g m₋₂ for Cryptomeria japonica (n = 4) and Chamaecyparis obtusa (n = 3). These values are comparable with or less than those reported for other temperate forests mainly in North America or Europe. Information on fine-root production in Japanese forests remains limited. Fine-root production accounted for ∼30% of the net primary productivity in two deciduous forests, but similar data was not reported for coniferous forests in Japan. In Japanese forests, slope position is a key parameter controlling fine-root biomass that is greater on upper slopes than on lower slopes, probably because soil resource availability decreases upslope. Studies in manipulated soil environments (e.g., removing throughfall to simulate drought) also suggested that fine-root biomass and production were greatly affected by altered soil environments. Physiological control of fine-root dynamics was recently discussed via anatomical analyses of Chamaecyparis obtusa. Findings from Japanese studies generally support data on fine-root biomass and production obtained from other temperate regions. Further attempts to elucidate the influence of slope position (soil resource availability) on fine-root production would be useful to gain a more detailed understanding of the fine-root dynamics in Japanese forests.     

控制锯材变形的方法

针对影响锯材变形的因素。从降低原木残余生长应力、对干缩湿胀和干缩应力的干燥工艺处理，到下锯法的合理选择，以及通过木材改性达到尺寸稳定等几方面进行了全面探讨，为提高锯材和木材品产品质量供参考。     

3种杀菌剂对甜瓜采后黑斑病菌的抑制效果

以不同浓度的嘧菌酯、醚菌酯和肟菌酯为供试药剂,研究其对引起甜瓜采后腐烂的黑斑病菌(A.alternata)菌丝生长的抑制效果。结果表明,不同浓度的杀菌剂对黑斑病菌(A.alternata)菌丝生长均有一定的抑制效果,而且随着浓度的增大,抑制效果增强。其中以嘧菌酯效果最好。     

辛树帜论中外科学十二大律提纲手迹考略

辛树帜先生论中外科学大律提纲手迹新近发现。本文参照其晚年学术思想和科研活动,详考遗稿文辞奥旨,探本发微,初识手迹系一坐而论道的提纲,旨在为创立中国水土保持学张本。所谓十二律亦缘比论治河论而发,意在确立中国水土保持在世界科学的大律地位,故文末并就各律略加阐释,以见手迹微言大义。     

我国农业面源污染的现状与控制技术研究

分析了我国农业面源污染的现状,阐述了我国农业面源污染控制存在的主要问题,提出了我国农业面源污染控制的有效策略。     

柿炭疽病鉴别与防治

[目的]研究柿炭疽病的鉴别与防治方法。[方法]研究柿炭疽病病原及特征、侵染与发生规律、为害症状,总结其防治方法。[结果]柿炭疽病病原为柿盘长孢菌,属半知菌亚门真菌。孢子萌发、入侵、菌丝体生长、产孢都需要较高的温度,最适温度为25℃,致死温度为50℃（10min）。柿炭疽病发生的强弱与寄主、环境、栽培情况等因素有关,主要为害果实和枝条。采用清洁果园、选用抗病品种和选栽无病苗木、平衡施肥、完善排灌系统、密植稀枝、利用坐地苗嫁接建园及提高嫁接部位的农业措施可控制病害的发生,病情严重则需要喷洒杀菌剂或保护剂,喷药时重点应喷施在嫩梢、果面和枝干的病斑上。[结论]该研究可为柿炭疽病防治提供参考。     

植物提取液对感染TMV烟叶中自由基含量及TMV增殖的影响

研究了商陆、落葵、毛叶子花和配伍植物(板蓝根等20种植物混合)的水提取液对感染TMV烟叶中自由基含量和TMV增殖的影响,并探讨了其防治TMV的效果。结果表明,不论在接种TMV毒液之前施用,还是接毒后施用上述植物提取液都能使O2·-和.OH含量降低,且对TMV增殖有较好的抑制作用,其中配伍植物提取液对TMV的防治效果优于单一植物提取液,并且预防效果大于治疗效果。     

土地资源详查中面积量测精度与线状地物扣除的探讨

本文从误差理论的角度,探讨了面积量测过程中,控制面积的精度与分区数目n之关系为:m_(?)=m(n~1/2),从而得出了通过控制分区数目n,来达到提高面积量测精度之目的。同时设计了线状地物两边扣除的辅助用表,以使面积汇总工作的顺利进行。     

大扫灭粉剂防治番茄根结线虫研究

[目的]进一步明确大扫灭粉剂的防治效果并推广应用于生产实践。[方法]98％大扫灭粉剂（有效成分：二硫代氨基甲酸钾和二甲基噻二嗪）设225、300、375kg／hm^2 3个处理（制剂用量）,处理土壤,防治番茄根结线虫,以10％福气多颗粒剂30kg／hm^2为药剂对照,同时设空白对照。研究大扫灭粉剂防治番茄根结线虫的效果。[结果]大扫灭粉剂可较好地控制番茄根结线虫危害。大扫灭粉剂225、300、375kg／hm^2 3个处理药后90d土壤中2龄幼虫数量减退率分别为67．01％、83．00％和94．55％,防治效果分别为66．14％、76．72％和84．39％;而对照药剂10％福气多颗粒剂30kg／hm^2处理的线虫减退率为83．42％,防治效果为82．41％。[结论]大扫灭粉剂可有效地控制番茄根结线虫的危害,有较高的推广应用价值。     

大蒜叶枯病防治初步研究

选用7种低毒广谱杀菌剂,对大蒜叶枯病进行了田间药效试验。试验表明：每666．7m^2用25％阿米西达悬浮剂20g．50％翠贝干悬浮剂10g和26．26％万兴乳油24ml,可有效防治大蒜叶枯病。