苏南稻田土壤持续生产力与种植制度关系研究

了苏南稻田不同种植制度与土壤持生产斩关系。维持土壤持续生产斩实质是土壤和，多熟种植制度发产出增加，加大了土壤养分的消耗，但有机物质生产增加，有利于有机物质归还和土壤有机质平均。在多熟种植制度中间套插种绿肥等豆等养地作物和油菜、蔬菜等培肥作物，结合秸村还田力轮作。将能维持稻田多熟制的土壤持续生产力。     

江苏沿江经济区多元多熟种植方式及效益评价

在江苏沿江经济区设置了２３种多元多熟种植方式进行定位对比试验，从增粮、增收和省工３个方面进行了综合评价。结果表明，稻田以“春玉米－水稻”为基础，旱地以春玉米为中心的粮饲经菜４元结构的省工型种植方式是本区集约高效持续种植制度的发展方向。     

浸润垄作稻田土壤表面物理现象及肥力意义

本文以淹水平作稻田为对照,讨论了浸润垄作稻田土壤表面物相界面特征以及对土壤水、热、气、肥的协调效应。浸润垄作稻田是气—液、气—固、液—固三种土壤表面物相界面共存,消除了淹水平作稻田水层覆盖对土壤和环境间进行的物质循环和能量转化的障碍效应;土壤表面水、热、气交换更新频繁,土壤养分代谢快,有效性高,构成了浸润垄作稻田高水平,高效应的物质循环和能量转化。     

长期不同施肥方式对江南稻田系统生产力与抗逆性的影响

依据29 a的田间施肥小区试验和4 a的养分耗竭盆栽试验,比较分析了不同施肥方式对江南丘陵稻田生产力及抗逆性的综合影响。结果表明,有机无机肥配施(NPK+OM处理)方式下,双季稻各季和周年生产力最高,其周年平均生物量和籽粒产量比化肥氮磷钾配施(NPK处理)高24.5%和20.2%。与单施氮肥相比,化肥氮磷钾配施显著提高了双季稻的氮素利用效率,而适量增施有机氮能够进一步提高氮素利用效率。化肥单施方式(N和NPK处理)下水稻周年籽粒产量呈递减趋势,下降幅度分别为43.7和1.8 kg.hm-2.a-1,而有机无机肥配施方式下水稻周年籽粒产量呈递增趋势,上升幅度为6.9 kg.hm-2.a-1。平衡施肥方式(NPK和NPK+OM处理)下,水稻各季及周年籽粒产量的年际变异较小,可持续性产量指数和系统生产力稳定性较高。养分耗竭试验4 a后,各处理水稻各季及周年生物量和籽粒产量高低基本表现为NPK+OM>NPK>N,试验期内周年籽粒平均产量以有机无机肥配施处理最高,说明有机无机肥配施的稻田土壤耐瘠能力高于其他施肥处理。可见,有机无机肥配施不仅能使稻田系统持续保持较高的生产力,而且能够提升系统的抗逆性,有利于江南丘陵稻田系...     

稻田综合种养模式对土壤生态系统的影响研究进展

稻田综合种养模式可实现稳产增收,粮渔共赢,同时也对稻田土壤生态系统产生了显著影响。该文总结了近年来国内外有关稻-鱼、稻-虾、稻-蟹、稻-鳖和稻-鸭等稻田综合种养模式的研究进展,分析了稻田综合种养模式对农田土壤理化性质、土壤动物、土壤微生物和农田生态系统服务功能的影响及作用机制。结果表明,稻田综合种养模式降低了土壤容重,提高了土壤孔隙度,改善了土壤团聚体的稳定性,增加了土壤养分含量;改变了土壤动物的丰度和群落结构,提高了土壤微生物的数量和活性,调节了微生物群落的组成和多样性;促进了农田生态系统的文化服务功能。然而,稻田综合种养模式也可能造成土壤潜育化、重金属污染等潜在风险。此外,不同的稻田综合种养模式对农田粮食供给和温室气体排放功能的影响各异。未来应进一步加强长期稻田综合种养模式对土壤物理、化学和生物学特性的影响研究;阐明不同稻田种养模式下土壤物质、能量和信息流过程以及土壤生态系统服务功能的差异及其作用机制;集成应用科学合理的稻田综合种养模式,实现农业的可持续发展。     

江苏沿江经济区多元多熟种植方式及效益评价

在江苏沿江经济区设置了２３种多元多熟种植方式进行定位对比试验，从增粮、增收和省工３个方面进行了综合评价。结果表明，稻田以“春玉米－水稻”为基础，旱地以春玉米为中心的粮饲经菜４元结构的省工型种植方式是本区集约高效种植制度的发展方向。     

凤眼莲生物炭对稻田土壤肥力的影响

我国南方稻田土壤在长期酸雨淋溶条件下养分淋失严重,不但制约了水稻等农作物的可持续生产,而且造成化肥资源的大量无效施用与水体富营养化的环境威胁.近年来研究表明,生物炭在减少亚马逊流域贫瘠土壤养分淋失方面具有突出效果,然而,关于生物炭对我国南方红壤性稻田土壤的养分保持作用研究报道较少.本实验以近几年在我国南方水域频繁暴发引发严重生态危害的入侵植物凤眼莲为生物质前体,于低温慢热解条件下制备生物炭,通过静态共育与模拟酸雨土柱淋溶,系统解析了凤眼莲生物炭(WBC)对稻田土壤养分的持留效果.结果表明:WBC的施用在有效提高土壤pH和CEC的基础上,能够显著增加土壤全N和速效K含量,但却使有效P含量随共育时间的延长而明显降低.在酸雨淋溶条件下,与对照相比,WBC处理中NH_4~+-N、NO_3-N和有效P淋失总量分别减少8.2%—49.8%,14.3%—76.2%和16.6%—43.3%,而K淋失总量提高16.5%—20.8%,但淋溶后WBC处理土壤中速效K含量仍显著高于对照,这表明淋溶液K浓度的升高主要来源于生物炭中丰富的水溶性K.根据以上研究结果,凤眼莲生物炭的施用在短期(1年)内有助于红壤性稻田土壤中主要矿质元素的保蓄持留,对减控稻田面源N、P流失具有重要作用,但其长期效应仍需定位试验的持续跟踪检测.     

铜污染土壤添加有机物质的生物效应Ⅰ. 对黑麦草生物量的影响

试验研究了泥炭和堆肥对铜污染土壤盆栽黑麦草生物量的影响。结果表明，在未添加有机物质的情况下，随着污染土壤铜含量的增加，黑麦草生物量呈明显减少的趋势（呈显著负相关），地下部分对铜毒害的反应比地上部分更敏感；导致黑麦草生物量减产20%的土壤铜含量在200～400 mg/kg之间。添加有机物质能显著促进黑麦草尤其是其地下部分的生长，使中度、重度铜污染土壤上的三茬黑麦草生物量平均增加80%～200%，并提高了导致黑麦草严重减产的土壤铜临界浓度。堆肥的增产效果好于泥炭。在试验的9个月内，有机物质仍能维持对受铜污染的土壤上的黑麦草生长的促进作用。     

有机农户和无机农户系统水稻生产的持久性分析

现代农业生产对环境的不良影响,使人们越来越重视农业生态系统的持久性问题。本文从水稻生产的独立性,生产力水平的长期维持和提高,养分的循环损失,土壤肥力的维持与改善及经济收入五个方面进行的研究分析都表明,有机农户系统的水稻生产比无机农户系统的持久性好。但是,有机农户系统目前的肥料投入水平和单产仍较低,有必要进一步开辟肥源,提高有机肥用量以提高单产,满足人口增长的需要。如何减少化学氮素的损失,减少其用量及对环境的污染,合理使用其它营养元素以保持稻田养分收支平衡,进一步改进栽培管理措施,则是无机农户系统水稻生产能否持续的关键之一。加强有机肥和无机肥配合使用对环境影响的研究,也许能为持久性农业提供新的依据。     

生物有机无机复合肥对土壤微生物活性的影响

进行了化肥、有机肥、生物堆肥、有机无机复合肥和生物有机无机复合肥的田间比较试验。结果表明：生物有机无机复合肥显著提高土壤微生物活性。与不施肥处理比较，土壤细菌增加了165．38％，真菌增加了189．47％，放线菌增加了48．72％，总量增加了104．07％，其增加量高于其他处理。土壤蔗糖酶、脲酶、磷酸酶活性也都有明显提高，促进了土壤有机质的分解转化和速效养分的释放。     

水土流失地区农田可持续利用的评价模型研究

通过水土流失地区不同农业生产方式对土地质量及土壤生产力的影响研究，探讨不同作物及其不同的种植方式对农田可持续利用的评价预测模型及土地资源利用的价值核算方法。通过对山西省闻喜县的案例应用验证，表明了在农业可持续发展研究中应用的可行性。     

Farmers' perceptions of constraints to plantain production in Ghana

SUMMARY

Plantain (Musa AAB), a primary food crop in Ghana, is a key component in sustainable agricultural systems in high rainfall zones. Recently, there has been a substantial yield decline and reduction in plantation life. To elucidate the context in which intervention strategies should be developed, a Participatory Rural Appraisal (PRA) was conducted at five villages in the major plantain-producing belt of Ghana. The importance of plantain as a preferred food was confirmed, although farmers tended to sell plantain for cash income, using cheaper, less preferred alternatives for home consumption. Farmers identified decreasing soil fertility, the high cost of labour for weeding, pests and diseases, lack of good quality planting material and marketing-related issues as the major production constraints. Due to declining productivity in less fertile regions, plantain has been replaced with other food crops such as cassava and maize. Farmers overestimated the importance of insect pests but were unaware of the extensive damage that could be caused by nematodes and the foliar disease, black sigatoka. They observed, however, that pest damage is more severe when soil fertility is poor. Clearly, integrated pest management is likely to be most effective when practiced within the context of cropping systems management; sustainable strategies that are being developed for resource-limited plantain farmers in Ghana are discussed.     

温州市粮食生产潜力及土地人口承载力研究

在光能生产潜力计算的基础上，经过温度、降水、土壤肥力和土壤质量等自然因素的订正，分析了温州市的土地生产潜力、粮食生产潜力。通过对温州市历年来主要粮食作物产量分析，采用产潜比增长速度法预测了２０００年和２０１０年的粮食产量，并据此计算了２０００年、２０１０年和潜在最大的人口承载量，指出温州市建立稳定协调可持续发展的人地关系的关键。     

Higher nitrates, P and lower pH in soils under medicinal plants versus crop plants

This report shows a higher soil quality under medicinal plants versus food-crop plants. Long-term continuous cultivation of food crops induces changes of soil properties that can lead to fertility loss and, in turn, decline of food productivity. Effect of cropping on soil changes has been studied mainly for food crops and vegetables worldwide, whereas soil changes in herbal fields are scarcely known. Therefore, we compared here soil nutrients and soil chemical properties of herbal fields, cultivated with Chinese medicinal plants, and food-crop fields. Fields are located at the famous traditional planting base of Chinese medicinal plants in Anguo, China. The results showed that in herbal fields, soil nitrate, available P, soil organic matter (SOM), and electrical conductivity decreased with soil depth, whereas soil pH and soil water content increased with depth. In herbal fields, soil nitrate, available P contents, and soil electrical conductivity were higher than those of food-crop fields at various soil layers. SOM and soil water content were similar in herbal and food-crop fields. Soil pH of herbal fields at 0–20 cm was lower than those of food-crop fields. Findings show overall that soil nutrient accumulation and changes under medicinal plants are higher than food-crop fields.     

江苏省沿江高沙土地区种植业可持续发展的技术途径研究

根据多年的生产实践经验和定位试验结果，提出了江苏省沿江高沙土地区多熟种植制、合理轮耕制、用养结合的培肥制和高产高效的栽培制相结合的种植业可持续发展的一体化技术体系，研究结果对我国中低产土壤地区种植业的持续发展具有重要意义。     

Life-cycle assessment of net greenhouse-gas flux for bioenergy cropping systems.

Bioenergy cropping systems could help offset greenhouse gas emissions, but quantifying that offset is complex. Bioenergy crops offset carbon dioxide emissions by converting atmospheric CO2 to organic C in crop biomass and soil, but they also emit nitrous oxide and vary in their effects on soil oxidation of methane. Growing the crops requires energy (e.g., to operate farm machinery, produce inputs such as fertilizer) and so does converting the harvested product to usable fuels (feedstock conversion efficiency). The objective of this study was to quantify all these factors to determine the net effect of several bioenergy cropping systems on greenhouse-gas (GHG) emissions. We used the DAYCENT biogeochemistry model to assess soil GHG fluxes and biomass yields for corn, soybean, alfalfa, hybrid poplar, reed canarygrass, and switchgrass as bioenergy crops in Pennsylvania, USA. DAYCENT results were combined with estimates of fossil fuels used to provide farm inputs and operate agricultural machinery and fossil-fuel offsets from biomass yields to calculate net GHG fluxes for each cropping system considered. Displaced fossil fuel was the largest GHG sink, followed by soil carbon sequestration. N20 emissions were the largest GHG source. All cropping systems considered provided net GHG sinks, even when soil C was assumed to reach a new steady state and C sequestration in soil was not counted. Hybrid poplar and switchgrass provided the largest net GHG sinks, >200 g CO2e-C x m(-2) x yr(-1) for biomass conversion to ethanol, and >400 g CO2e-C x m(-2) x yr(-1) for biomass gasification for electricity generation. Compared with the life cycle of gasoline and diesel, ethanol and biodiesel from corn rotations reduced GHG emissions by approximately 40%, reed canarygrass by approximately 85%, and switchgrass and hybrid poplar by approximately 115%.     

Impact of phosphorous on biochemical changes in Hordeum vulgare L. in mixed cropping with chickpea

Multiple cropping (i.e. intercropping or mixed cropping) plays an important role in agriculture because of the effective utilization of resources, significantly enhancing crop productivity compared with that of monocultured crops. The study was planed to assess the effect of various concentrations (00, 30, 60, 90 kg ha(-1)) of phosphorous on the biochemical composition of grains of Hordeum vulgare L. (NDB-1050) in mixed cropping system with Chickpea. Phosphorous is an essential ingredient for plants to convert atmospheric N (N2) into an ammonium (NH4) as a useable form. The available nitrogen content was found more in the year 2006 (131 kg ha(-1)) than year 2005 (105 kg ha(-1)). The results of available nitrogen content were showed that the mixed cropping system enhances N fixation process because phosphorous also influences nodule development through its basic functions in plants as an energy source. Reducing, non reducing and total sugar content of H. vulgare L. were influenced by changes in the phosphorous doses. Maximum protein (13.43%) was obtained at 60 kg P2O5 ha(-1) during the year 2006. Lysine, tryptophan and methionine content were found maximum in year 2006, respectively. Total mineral content of grains of plant (0.99 g 100g(-1)) was found maximum by the application of 60 kg P2O5 ha(-1). It is possible that there was an increase in the soil N made available by the leguminous chickpea species, and this could be another reason why there was an increase in Hordeum vulgare L. shoot mass per plant with intercropping with chickpea.     

A simulation study of the medium-term effects of field patterns on cross-pollination rates in oilseed rape (Brassica napus L.)

Gene flow between cultivars within a landscape may lead to impurities that reduce harvest value. In OSR, as for most crops, impurity rates are expected to depend on the spatial distribution of crops over the landscape. However, in contrast to other well-studied crops such as maize, OSR crops generate seed banks in European agro-ecosystems. Gene flow is thus a spatio-temporal process which depends on cropping systems. We therefore aimed at identifying spatial variables that have an effect on regional or local harvest impurities, taking account of the time since the introduction of OSR crops in the regions and of cropping system. Gene flow was simulated over 36 field patterns cultivated with either 15% or 30% of OSR fields, among which 10% or 50% were GM, for three contrasted cropping systems, with the GeneSys software already used for EU co-existence studies. Through regression analyses, we determined spatial and agronomic factors that most affected harvest impurity rates of non-GM OSR after one or seven years of OSR cultivation. The cropping system was the main factor explaining regional harvest impurity rates. Its importance increased after six years of OSR cultivation. For a given cropping system, the regional impurity rate after one year increased linearly with the current proportion of GM crop. In contrast, impurity rates after six years largely depended on the proportions of OSR crop (GM or not) in the two preceding years. During the first year of OSR cultivation, local impurity rates were mostly explained by the distance to the closest GM field. After six years, these rates were mostly explained by the density of GM volunteers in the analysed field and, to a lesser degree, to that of volunteers in neighbour non-OSR fields. Cropping systems were most important in determining impurity rates and the way impurity rates related to regional or local factors. Determination of isolation distances to ensure harvest purity should thus consider past history of OSR cultivation in the area and, in particular, how current or future cropping systems will manage volunteers. Regression quantiles were fitted to the simulated data to determine regional rules (i.e. the maximum regional area of GM OSR and isolation distances between GM and non-GM crops) as a function of the risk accepted by the decision-maker (i.e. the % of situations exceeding harvest impurity thresholds), the cropping system and the volunteer infestation.     

玉米-花生混作系统中的氮铁营养效应

采用盆栽试验的方法研究了不同施氮水平和种间相互作用对花生铁营养、根瘤固氮能力以及系统氮营养的影响。结果表明,在本试验种植密度下,施氮水平和种植方式对下针期单株花生生物量无显著影响。在不同施氮水平下,玉米-花生混作不仅均显著改善了花生铁营养,而且玉米对氮素的大量吸收显著降低了混作花生根际土壤硝态氮的质量分数,从而使得花生根瘤数增加,根瘤固氮酶活性增强。混作花生铁营养受混作玉米氮营养及作物发育状况的影响较大,并且下针期花生固氮酶活性受施氮抑制及花生铁营养改善的促进。这说明,根际土壤硝态氮的质量分数的降低和花生铁营养的改善是石灰性土壤上花生固氮能力增强的关键因素,而花生生物固氮作用的增强是该混作系统体现氮营养优势的主要原因。