土壤酸度对茶树生长的影响

生产实践中发现,茶树裁在坟堆、庙宇遗址和石灰性土壤上,茶树不能成活。很多生产部门都提出过这种问题。为了查明产生这种现象的原因,曾对几个茶场的土壤进行了调查,并采集一部分有代表性的土壤样品进行分析。     

马铃薯连作障碍及其防控的研究进展

连作障碍现象在马铃薯生产中普遍存在,已成为制约中国马铃薯产业发展的主要原因之一.马铃薯连作障碍的形成是多个复杂因素相互作用产生的结果,包括土壤酶活性的改变、土壤养分失衡、自毒物质积累、土壤微生物区系改变、土壤次生盐渍化及酸化.如何解决马铃薯连作障碍已成为当前迫在眉睫的问题,因此针对难题具体阐述了轮作、抗性品种应用、土壤...     

棚龄对大棚土壤重金属及盐分含量的影响

阐明大棚棚龄对大棚土壤中重金属及盐分含量的影响,并为解决由此而产生的大棚蔬菜和水果的产量下降、品质变劣的问题及解决农业生产中的实践问题提供理论支持。综述了调查的不同地区和不同棚龄蔬菜大棚土壤中的重金属和盐分含量。研究发现部分大棚土壤中存在重金属污染超标现象,且随着棚龄的增加重金属含量不断上升,同时大棚土壤盐渍化趋势随栽培年限的延长愈加明显,且主要是Cl-、NO3-含量的增加。总之,大棚土壤中重金属含量升高和土壤盐渍化的原因,主要是施肥（复合肥）过量和施肥不当引起。     

茶园土壤磷含量和灌木泡囊菌(VAM)侵染的关系

茶树较适于 pH 值低于5的酸性土壤。在酸性土壤中,Al 被电离后极为活跃,所以许多植物受电离Al(Al)的毒害。受毒害现象还包括由于缺 P 而诱发产生 Al 多 P 少的综合病症,但此时茶树体内仍不产生缺 P现象。Al 的存在甚至还可能刺激茶株生产和P 的吸收(Konishi,1988)。在这些条件下,     

钙基调理剂对酸化农田土壤的调控效果研究

农田土壤酸化已成为制约农业发展的全球性问题,在强降雨淋溶地区尤为严重。本研究利用硝酸磷肥生产过程中所产生的中间产物制造的低pH值土壤调理剂来改良酸化土壤。结果表明：该调理剂按用量1 g/kg(折合亩施150 kg)即可显著地提高土壤pH值,且其在不同pH值土壤上的施用效果有所差异;施用后短期内存在返酸现象;该调理剂与约一半用量的生石灰的调控效果相当;调理剂对土壤有效磷含量的影响因土壤性质不同而异;施用调理剂对土壤有效钾的影响不显著。     

Azospirillumb rasilense作生物肥料在冬小麦约栽培中的应用

在温带集约经营的农业生产中,用微生物来改善大田作物产量组分的问题,一向被人们所忽视.除利用根瘤菌与豆科植物的共生关系之外,人们只强调土壤中有害微生物对集约化农业生产的作用,而不重视有益微生物的作用.只有在很少的场合下,农学家们才用微生物当作生物肥料,来固定大气中的氮素、溶解土壤中的迟效磷或产生植物激素.     

云南元江山地香蕉无公害栽培

元江是云南最适宜发展香蕉的区域之一,目前坝区香蕉种植开始往山地发展。山地土壤灌溉条件以及香蕉栽培的特殊性,导致山地香蕉生产难以产生较好的经济回报。通过近几年山地香蕉栽培实践,总结了一套山地香蕉无公害栽培关键技术,解决了山地香蕉栽培的特殊性与土壤水肥灌溉条件的矛盾。     

湖北省红安县耕地培肥与改良利用研究

在全面认识红安县土壤发生特性、分布和生产力的基础上，根据土壤分类，将土壤群体中具有共同特性和生产特征的土壤组合划分为各种土壤区。，根据红安县实际情况，提出不同地区的改良方向和增产途径为因地制宜合理配置农、林、牧各业，合理安排生产，充分利用土壤资源，发挥土壤生产潜力，提高农业生产的经济效益提供了科学依据.     

桂阳特色优质烟叶成因初探

介绍了桂阳优质烟叶相对稳定的地方特色,分析了特色烟叶产生的原因:一是当地的温、光、水资源最适宜优质烤烟生产,且其季节分布与烤烟生长发育各阶段的需求相吻合;二是桂阳土壤多为石灰岩和钙质板页岩发育的红壤、红黄壤和部分紫色页岩发育的紫色土,都是种烟的适宜土壤;三是烟农在长期实践中创造了许多具有地方特色的栽培技术。     

地膜残留土壤对花生生育影响的研究

残膜片存留在土壤中,随存留量大小,对花生的生长与发育均产生一定影响。尤以构成产量因素的单株结果数和单株生产力的影响较大。同时,对土壤理化性状和土壤微生物消长,以及对根系发育和根活性也产生不同程度的影响,残膜片在土壤中分布角度,以180°时影响为最明显。     

西藏茶叶生产现状、自然优势及建议

对西藏南部和东南部茶树种植、生长及气候、土壤等进行了考察,分析了该区茶叶生产的潜力、优势和影响茶叶发展的主要因素,并提出了建议。西藏茶区茶树生长及生态条件与内地茶区接近甚至更优越,春夏秋各季均可生产名优茶。在海拔１１００ｍ以下的红壤地带种茶优势明显,在海拔１１００—２５００ｍ的黄棕壤和黄壤地带种茶具有较大潜力,但在海拔２５００ｍ以上的高地种茶须慎重     

中国小麦种植区域的生态特点

为给进一步研究中国小麦种植区划提供依据,在大量调查和搜集资料的基础上,分析了中国小麦种植区域分布、气候和土壤特点、种植制度以及品种类型.结果表明,中国小麦分布地域辽阔,全国各省区均可完成小麦生活周期,目前除海南省外其余各省(区)均有小麦统计面积.中国小麦种植区域气候因素多样,从寒温带逐步过渡到温带、亚热带和热带地区.小麦种植区域土壤类型复杂,土壤质地多为壤土,次为砂壤土和粉土,少有黏土和砂土.种植制度主要包括一年一熟、一年两熟、两年三熟或一年三熟.中国小麦生产中主要以普通小麦品种种植为主,这些品种根据春化特性可分为春性、冬性和半冬性小麦三大类型.     

Rate of leaf production in response to soil water deficits in field pea

Plant leaf area is critical for predicting the amount of radiation intercepted by a crop, and thereby, for estimating dry matter production. Under soil water deficit conditions, plant leaf expansion is reduced as a result of both a reduction in the rate of leaf production (RLP) and in the rate of individual leaf expansion. Quantifying the effect of soil water deficits on plant leaf expansion depends in part on predicting its effects on the timing of leaf production. The effect of soil water deficits on RLP was examined for three pea cultivars in greenhouse and field experiments. The level of soil water deficit was characterized as the fraction of transpirable soil water (FTSW). A quantitative function between RLP and FTSW was established in greenhouse experiments and was tested in independent pot and field experiments. A good consistency in this relationship across a diversity of experimental conditions and cultivars was shown. The logistic function obtained represents an effective way to simulate the effects of soil water deficits on RLP, especially as FTSW could be estimated from a soil water balance. RLP was reduced only for FTSW<0.2, and consequently, RLP was less sensitive to soil water deficits than transpiration and leaf expansion. Soil water deficit induced a slight rise in canopy temperature due to stomatal closure. However, this rise in temperature for FTSW<0.4 cannot account for maintaining RLP compared to the drop of transpiration and of leaf expansion rates observed for FTSW between 0.4 and 0.2. RLP can be considered independent of soil water content if FTSW>0.2. In the field, such level of soil water deficit inducing a decrease of RLP occurs generally only after the end of leaf production during the last reproductive stages of pea crop. Thus, except in situations of extreme soil water deficit and on shallow soils, leaf production depends solely on air temperature.     

测土配方施肥对黑龙江省讷河市大豆生产的影响

本试验针对我市多数农民大豆生产施肥存在重氮、轻磷忽视钾的现状，结合测土配方项目工程进行大豆测土配方施肥研究。结果表明：与当地习惯施肥相比，应用测土配方施肥技术具有改善大豆主要经济性状、促进大豆健康生长、提高大豆产量和产值。扣除投入成本，测土配方施肥比当地习惯施肥净增产值76．8-118元／667m^2，平均98．65元／667m^2；较对照净增产值91．3-137．9元／667m^2，平均112．3元／667m^2。     

育苗基质对水稻秧苗素质及产量的影响

针对水稻育苗土日益贫乏,黑土资源浪费严重等问题,研制了新型水稻育秧基质替代传统土壤基质育苗。试验结果表明:采用新基质育苗能培育壮苗,提高水稻产量,有助于解决水稻育苗取土难问题和保护有限的黑土资源,是水稻生产可持续发展的有效途径。     

减量配施腐植酸肥对连作马铃薯及土壤的影响

当前马铃薯生产中,农民过量及盲目施肥现象严重,造成生产成本增加、土壤理化性状恶化、环境污染加剧等问题,为解决这类问题,确定合理减量施肥量,有效指导马铃薯科学种植,特开展试验.选用常用复合肥、腐植酸复合肥及腐植酸控释氮肥3种不同类型肥料为基肥,每种肥料分别设置常量施肥和减量30％施肥两个处理,共6个处理.通过测定马铃薯产...     

Potential impacts of climate change on patterns of production and the role of drainage in grassland

Grass production can be predicted using a simple model whose inputs include daily meteorological variables. Changes in both daily temperature and the soil water balance can be expected as a consequence of anthropogenic increases in the CO₂ content of the atmosphere. Possible consequences of such changes for grass production are then predicted using the model. These indicate that, for the UK, patterns of grass production could be shifted significantly. Greater grass growth in the spring would follow from the increase in temperature, particularly on drained land where growth is not constrained by water logging. However, grass growth would be depressed by the mid-season soil moisture deficit, and this again is more marked on drained land, it is concluded that, under a changed climate, the drainage of grassland to enable early season access to the land, together with sound management to optimize output, will be even more important than at present.     

Implications of Elevated CO2-Induced Changes in Agroecosystem Productivity

SUMMARY

Since CO₂ is a primary input for crop growth, there is interest in how increasing atmospheric CO₂ will affect crop productivity and alter cropping system management. Effects of elevated CO₂ on grain and residue production will be influenced by crop selection. This field study evaluated soybean [C₃; Glycine max(L.) Merr.] and grain sorghum [C₄; Sorghum bicolor (L.) Moench.] cropping systems managed under conservation tillage practices and two atmospheric CO₂ concentrations (ambient and twice ambient) for three growing seasons. Elevated CO₂ increased soybean and sorghum yield by 53% and 17% increase, respectively; reductions in whole plant water use were also greater for soybean than sorghum. These findings suggest that increasing CO₂ could improve future food security, especially in soybean production systems. Elevated CO₂ increased aboveground residue production by > 35% for both crops; such shifts could complement conservation management by increasing soil surface cover, thereby reducing soil erosion. However, increased residue could negatively impact crop stand establishment and implement effectiveness during tillage operations. Elevated CO₂ increased total belowground dry weight for both crops; increased root proliferation may alter soil structural characteristics (e.g., due to increased number and extent of root channels) which could lead to increases in porosity, infiltration rates, and subsequent soil water storage. Nitrate leaching was reduced during the growing season (due to increased N capture by high CO₂-grown crops), and also during the fallow period (likely a result of altered decomposition patterns due to increased C:N ratios of the high CO₂-grown material). Enhanced crop growth (both above-and be-lowground) under elevated CO₂ suggests greater delivery of C to soil, more soil surface residue, and greater percent ground coverage which could reduce soil C losses, increase soil C storage, and help ameliorate the rise in atmospheric CO₂. Results from this study suggests that the biodegradability of crop residues and soil C storage may not only be affected by the environment they were produced in but may also be species dependent. To more fully elucidate the relationships between crop productivity, nutrient cycling, and decomposition of plant materials produced in elevated CO₂ environments, future studies must address species effects (including use of genetically modified crops) and must also consider other factors such as cover crops, crop rotations, soil series, tillage practices, weed management, and regional climatic differences.     

环渤海低平原区青贮玉米垄作覆膜种植模式研究初报

为探索环渤海低平原区青贮玉米最佳种植模式,本试验以等行距露地平作为对照,研究了6种种植模式对青贮玉米光合特性、产量及耕层土壤水分、温度变化的影响。结果表明,宽窄行种植和起垄覆膜均能提高青贮玉米的光合速率、叶绿素含量和叶面积指数,同时各覆膜处理均能提高0~20 cm土层的土壤含水量和土壤温度。其中40/70垄作膜侧模式效果最优,较对照增产30.52%,差异达到显著水平。综合分析认为,40/70垄作膜侧模式具有土壤增温、集雨保墒、促进光合、稳产增产作用,在春季干旱少雨的滨海平原区具有广阔的应用前景。     

A simple statistical model for predicting herbage production from permanent grassland

The considerable year‐to‐year and seasonal variation in grassland production is of major importance to dairy farmers in Europe, as production systems must allow for the risk of unfavourable weather conditions. A large portion of the variability is caused by weather and its interaction with soil conditions and grassland management. The present study takes advantage of the interactions between weather, soil conditions and grassland management to derive a reliable grassland statistical model (GRAM) for grasslands under various management regimes using polynomial regressions (GRAM‐R) and neural networks (GRAM‐N). The model performance was tested with a focus on predicting its capability during unusually dry or wet years using long‐term experimental data from Austrian sites. The GRAM model was then coupled with the Met&Roll stochastic weather generator to provide estimates of harvestable herbage dry matter (DM) production early in the season. It was found that, with the GRAM‐N or GRAM‐R methodology, up to 0·78 of the variability in harvested herbage DM production could be explained with a systematic bias of 1·1–2·3%. The models showed stable performance over subsets of dry and wet years. Generalized GRAM models were also successfully used to estimate daily herbage growth during the season, explaining between 0·63 and 0·91 of variability in individual cases. It was possible to issue a probabilistic forecast of the harvestable herbage DM production early in the season with reasonable accuracy. The overall results showed that the GRAM model could be used instead of (or in parallel with) more sophisticated grassland models in areas or sites where complete data sets are not yet available. As the model was tested under various climatic and soil conditions, it is suggested that the proposed approach could be used for comparable temperate grassland sites throughout Europe.