An Evaluation of the Introduction of Modified Cropping Practices in Yunnan Province, China, Using Surveys of Farmers＇ Households

Problems associated with land degradation are serious in China. Sloping land in South China has experienced a decline in crop productivity by 30-60% due to soil erosion and it has been predicted that most topsoil will be lost within the next 100 years if current erosion rates continue. Considering these situations, an agro-environmental research and development project （Sustainable Highland Agriculture in South-East Asia- SHASEA） was conducted in a catchment in Yunnan Province, China, to address the objectives of increasing crop productivity in sustainable and environmentally-friendly ways. A range of cropping practices was developed and implemented in a rural upland catchment （Wang Jia）. At the end of the project, farmers were surveyed to evaluate project effectiveness. All farmers from Wang Jia Catchment, who were involved in project implementation, were surveyed. A sample of farmers working in an adjacent catchment （not associated with the project） was surveyed for comparative purposes. Farmers had different perceptions of the cropping practices employed. Contour cultivation was preferred and likely to be adopted. Others practices such as straw mulching and intercropping were seen as less appropriate and unlikely to be adopted. Polythene mulch was recognized as effective, but likely to be adopted only if financial returns were favourable. The availability of relevant information had an important impact on the extent of technology testing by farmers and their willingness to adopt the practices in the future.     

“甜瓜——粳稻——蔬菜”高产高效栽培技术

近年来南京市浦口区积极推进稻田种植制度创新,示范推广了"水稻+N"新型高效种植模式,对建设资源节约型社会、推进种植业高效规模化、增加农民收入、建设生态农业、改良土壤和减轻农作物病虫害的发生十分有利.其中"甜瓜--粳稻--蔬菜"种植模式在乌江镇示范推广较快,2008年种植面积70 hm2,一般纯收入5.85万元/hm2.文中从茬口安排、品种选用和栽培技术要点等方面论述了该模式的高产高效栽培技术.     

旱地马铃薯连作对土壤养分的影响

[目的]为改良马铃薯连作地块的土壤提供指导。[方法]以甘肃省定西市安定区团结镇唐家堡村马铃薯连作0,3、5年的土样和该市渭原县会川镇马铃薯连作0,3、7年的土样为材料,考察马铃薯连作年限对土壤养分含量和pH值的影响。[结果]随马铃薯连作年限的增加,2地区土壤全氮、全磷、全钾含量总体呈下降趋势,但不同连作年限间差异不显著;碱解氮、速效磷、速效钾含量有不同程度的下降;Fe、Mn含量下降,Cu、Zn含量无明显变化;唐家堡地区土壤pH值呈增加趋势,会川地区土壤pH值表现为：连作3年〉连作7年〉连作0年。[结论]马铃薯连作打破了土壤养分平衡,改变了土壤理化性质。     

强化栽培稻田主要病虫害的发生规律研究

研究了强化栽培单季稻稻田生态系统中水稻主要病虫的发生规律及使用农药防治靶标病虫时对非靶标病虫的影响。结果表明,强化栽培方式下褐飞虱种群数量较常规栽培方式增加了21.47%,白背飞虱增加了27.19%,稻纵卷叶螟增加了57.95%,二化螟增加了200.0%,纹枯病病情指数增加了29.10%。防治病虫靶标对非靶标病虫种群发展的影响以稻飞虱最为突出,用杀虫双、茚虫威、井冈霉素和苯甲·丙环唑等药剂防治螟虫、稻纵卷叶螟和纹枯病等靶标病虫时,均会刺激褐飞虱和白背飞虱种群数量增殖,其增殖幅度较常规栽培方式提高了26%～60%。     

免耕抛栽水稻的根系特性初步研究

通过2005—2007年连续3 a定位试验,在双季稻田研究了免耕抛秧水稻的根系特性。结果表明：免耕抛秧水稻根系干重低于翻耕移栽稻,根系大部分分布在表层（0-5 cm土层）土壤。水稻单穴根系固持力表现为翻耕移栽〉翻耕抛秧〉免耕抛秧,且随着免耕年限的延长,这种趋势更明显。     

不同大豆品种幼苗叶片光合及叶绿素荧光 特性对套作遮荫的响应

选用4个耐荫性有差异的大豆品种为材料,通过与单作比较,研究了不同大豆品种幼苗叶片光合及叶绿素荧光特性对套作遮荫的响应差异。结果表明,套作遮荫提高了大豆叶片叶绿素含量、总叶绿素与类胡萝卜素比值（Chl(a+b)/Car）、胞间二氧化碳浓度（Ci）、水分利用效率（WUE）、叶片初始荧光（Fo）、PSⅡ有效光化学量子产量（Fv′/Fm′）和实际光化学效率（ΦPSⅡ）;使叶绿素a与叶绿素b比值（Chla/b）、类胡萝卜素(Car)含量、净光合速率（Pn）、气孔导度（Gs）、气孔限制值（Ls）、蒸腾速率（Tr）、PSⅡ最大光化学量子产量（Fv/Fm）、光化学荧光猝灭系数（qP）、非光化学荧光猝灭（NPQ）呈减小趋势。套作遮荫降低了大豆地上部分干物质积累量,其干物质积累量与Pn呈极显著正相关。耐荫性相对较好的材料,如贡选1号和南豆12在套作遮荫下Pn下降较少,且有着相对较高的Chlb、Car分子组成比例、Fo和Fv/Fm。     

北美马铃薯新品种在福建冬种的表现

福建冬种马铃薯主栽品种为紫花851,该品种虽在福建种植表现高产稳产,但其薯块芽眼深,裂薯率偏高,干物质含量偏低,商品性较差,晚疫病的抗性减弱,生产上迫切需要高产优质抗病等各类新品种。本研究引进北美育成的6个马铃薯品种,以紫花851为对照,采用随机区组试验设计,评价它们在福州的植物学性状、生育期、块茎性状、总产量、商品薯产量及其抗病性。6个品种的生育期介于90～98d,其中生育期最长的为NY128。各品种抗性较好,干物质含量介于18.18%～21.18%之间,鲜薯产量每667m2介于1347.5～1924.0kg,其中Salem和CalWhite量较高,增产达显著水平,薯块大中薯率高,商品性好,可进一步进行示范试种。     

不同供N方式对大豆生长和结瘤固氮的影响

采用框栽试验方法对比研究了不同供N方式对大豆生长和结瘤同氮的影响.结果表明:持续供N和非持续供N对大豆生长有不同的影响,在苗期,非持续供N与持续供N相比,对大豆生长有较大的促进作用,而在仡期以后则是持续供N对大豆生长的促进作用较大;持续供N和非持续供N对大豆结瘤同氮的影响不同,大豆根瘤数量表现为非持续供N＞持续供N＞无N,表明氮肥的持续施用对大豆根瘤的形成和生长有抑制作用,不利于大豆根瘤的生长发育;不论何种方式供N对大豆同氮酶活性和豆血红蛋白含量均有抑制作用,使固氮酶活性和豆血红蛋白含量显著降低,而且氮肥的持续施用对固氮酶活性和豆血红蛋白含量的抑制要显著高于非持续供N,表现为持续供N＜非持续供N＜无N,因此,氮肥的持续施用使大豆的同氮效率降低.     

五趾跳鼠的植物性食物选择与其栖息地植被的关系

2001年7-9月,在短花针茅荒漠草原捕获五趾跳鼠(Allactaga sibirica Forster)107只,将其中60只鼠胃内容物对比已知植物表皮的显徽结构进行分析,以确定其植物性食物组成。结果表明:五趾跳鼠是以植物性食物为主的杂食性啮齿动物,植物性食物占其食物量的95%以上;五趾跳鼠具有较固定的觅食策略,对植物性食物具有较明显的择食性,在同一时间段内与栖息地植被群落组成的变化无明显的关联性,虽然连续放牧区和轮牧区两种栖息地之间的植被组成有极大的差异,但是五趾跳鼠的植物性食物组成在两种栖息地之间差异不大,相似性指数为0.71~0.88。五趾跳鼠经常采食的植物种类有冷蒿(Arternisia frigida Willd.)、木地肤(Kochia prostrata(L.) Schrad.)、阿尔泰紫菀(Heteropappus altaicus(Willd.)Novopokr.)、冠芒草(Enneapogon borealis(Griseb.)Hon-da)、小画眉草(Eragrostis minor Host)、短花针茅(Stipa breviflora Griseb.)、无芒隐子草(Cleistogenes songorica(Roshev.)Ohwi)、葱属植物(Allium spp.)、猪毛菜(Salsolacollina Pall.)和茵陈蒿(Artemisia capillaris Thunb.)等。     

A simulation model assisted study on water and nitrogen dynamics and their effects on crop performance in the wheat-maize system: (II) model calibration, evaluation and simulated experimentation

The test on the model with data collected from two years’ field experiments revealed an ability to satisfactorily simulate crop parameters such as LAI, biomass accumulation and partitioning, yield, and variables influencing crop growth and development as nitrogen uptake by crops and partitioning in different organs, and dynamics of soil water and nitrogen including infiltration and leaching. With the model, crop yield, water use efficiency (WUE), nitrogen use efficiency (NYE) and water-nitrogen leaching at specific soil layers under various water and nitrogen management practices were simulated to provide data used as references for designing sustainable nitrogen and water management practices. The outputs of the simulated experiment with various treatments of irrigation and nitrogen application indicated that crop yield was closely related to water and nitrogen application, crop water use was positively related to irrigation amount, and nitrogen fertilization could improve the crop water use and WUE within certain limits. This is a valuable evidence to be considered in water-saving farming. Nitrogen uptake had a positive relation to nitrogen application, while irrigation to some extent improved its uptake by crops and hence increased NYE. Additionally, irrigation and fertilization had great effects on nitrogen leaching. Thus, in order to improve WUE and NYE, the model showed how nitrogen application and irrigation should be well coordinated.