北方农牧交错带典型农户系统的能值分析

本文通过对北方农牧交错带两个典型农牧经营的农户的生产系统进行能值分析研究后表明在该地区总体上他们仍未摆脱广种薄收的生产方式,能值产投比的增加是依靠畜群超载数量的增加,这样对环境产生了巨大的压力。因此应尽快建立严格的舍饲养殖和草畜平衡,控制畜群数量,调整结构,提高净能值产出率,降低系统的环境承载率,才能实现区域的可持续发展。     

Tree windbreaks and shelter benefits to pasture in temperate grazing systems

The effects of windbreaks on pastures are reviewed, with an emphasis on temperate grazing systems. Mechanisms of plant response to shelter are dealt with in brief. Few papers on measured responses of pasture species to shelter were located in a search of the global literature for the period 1972–97. Except in cold climates, where the benefits of snow-trapping on water availability can be demonstrated, there were few reports of increased production of pasture in response to shelter. A significant result was obtained in a summer rainfall environment in Australia, where a 43% increase in wool production was obtained over three years in small plots sheltered with iron sheeting on the fences. The gain was attributed to increased pasture growth. In New Zealand, one study over three years with a narrow, permeable shelterbelt in a windy, dry summer environment showed a 60% increase in pasture growth in the sheltered zone. However, another study on a high rainfall site with a dense, wide shelterbelt found no substantial shelter effect on pasture. In dry, hot and windy climates there appears to be scope for protecting spray-irrigated pasture with windbreaks. The feasibility of evaluating shelter effects on pastures or crops from old windbreaks is questioned. Variability of soil over the site can not be satisfactorily accounted for and there are problems in defining the true ‘unsheltered’ yield. Shelter effects on pastures could best be determined by comparing production in small completely sheltered plots and open plots. Effects in and near the competitive zone should be measured for living windbreaks. Modelling could then be used to evaluate windbreak systems. We are not yet in a position to provide unequivocal advice to farmers on windbreak outcomes for particular purposes or regions. This revised version was published online in June 2006 with corrections to the Cover Date.     

基于能值理论的农牧交错带两个典型县域生态经济系统的耦合效应分析

农牧交错带生态经济系统耦合效应与区域经济的可持续发展紧密相关,该文运用能值理论与方法,首次提出了农牧系统耦合度的概念,并对农牧交错带两个典型县域的农牧系统耦合现状进行了分析。结果表明农牧耦合效果不好,主要表现为两种典型结构模式,一种以安塞县为代表,农牧能值总体利用率较高,但畜牧业内部结构偏重食粮动物使得高质能转化率低下;另一种以武川县为代表,农牧业结构总体上朝趋于协调方向发展,但畜牧业规模过大,由于草畜平衡严重失调,导致农牧系统耦合机制难以稳定。该文根据能值指标分析结果,还提出了提高农牧系统耦合的一些措施及关于产业结构调整的探讨。     

豆制品行业废弃物转化生物有机肥的探索性研究

以清美公司豆制品生产中的废弃物豆渣和经过预处理的黄浆水污泥为原料,探索性研究2种调理剂以及堆体不同碳氮比对豆渣黄浆水污泥共堆肥发酵的影响。依据植物发芽率来确定调理剂添加量及碳氮比;测定分析堆肥发酵过程中温度、时间的变化趋势,并进行堆肥成品肥效检测。研究结果表明:豆渣与黄浆水污泥共堆肥的发酵最佳工艺为:调理剂选用秸秆粉,投加量为15 kg,C/N=25∶1。3#堆体发酵过程中高温温度(>50℃)可持续5 d以上,浸提液发芽率96.6%。堆肥成品肥效检测结果符合国家标准,可作施用于植物的中等肥料。     

Long-term sustainability of wood-pasture separation processes—A matter of seed mixtures and management

We studied the performance of different seed mixtures and the influence of liming on the establishment of a montane pasture under acidic site conditions during a wood-pasture separation process from 1998 to 2001 in Styria, Austria. Two treatments (with and without liming) were established, each with four seeding treatments (without seeding, commercial, site-adapted and site-specific mixtures), and all plots were regularly fertilized from 1998 to 2002. Vegetation surveys and forage analyses regarding development of vegetation cover, seeded species persistence, quality and yield parameters were conducted again in 2014 and 2016; soil samples were taken in 2015. After cessation of regular fertilization, the analysed soil parameters declined to levels that were sufficient or low for grasslands. pH decreased again over time, but still was significantly higher (p = .0034) in the liming treatment. The single liming during experimental set-up also caused better long-term performance for nearly all vegetation, quality and yield parameters. The site-specific seed mixture performed best regarding most analysed parameters, under both liming treatments. Concerning seeded species, the habitat-typical species Agrostis capillaris, Festuca rubra agg. and Trifolium repens persisted best with and without liming. All analysed vegetation and yield parameters stayed far behind their results of 2001 and their potential. The use of site-specific seed mixtures supports the establishment of productive grassland on specific locations. The long-term results also illustrated that even low-input management like liming in multi-annual intervals can help to improve acidic site and growing conditions significantly and thereby increases the sustainability of cost-intensive wood-pasture separation processes under similar conditions.     

Managing “Marandu” palisadegrass and calopo pastures based on light interception

Light interception (LI) in grazing management has been an efficient tool to harvest forage under similar growth stage conditions. The objective was to define the best grazing management strategies (GMSs) based on LI in marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] R. Webster cv. Marandu) and calopo (Calopogonium mucunoides Desv. cv. Comum) mixed pastures. Three GMSs were evaluated in a randomized block design: rest period interrupted at 90% (90LI), 95% (95LI) and 100% (100LI) of LI. The experimental period was divided into four periods: rainy seasons and transitions (between rainy and dry seasons). Post-grazing stubble height target was 15 cm. Canopy height, forage mass, leaf area index (LAI), morphogenic variables and tiller demographic pattern were evaluated. Pre- and post-grazing canopy height increased at 100LI. Pre-grazing forage mass decreased over time in all GMSs. The relationship among canopy height, forage mass and LI was not constant throughout the experiment. Post-grazing forage mass was greatest at 90LI. There was an increase in legume mass throughout the experiment; however, the proportion of legume in pre-grazing forage mass was no more than 6.6% for all GMSs. Number of calopo branches per plant and LAI increased throughout the experiment while the number of plants decreased. The 95LI provided the best conditions for calopo development; however, the LI as a tool to determine the entry of animals in mixed pastures of marandu palisadegrass and calopo should be carefully applied, considering the seasonal variations in canopy botanical and structural composition under similar LI.     

How does pasture size alter plant–herbivore interactions among grazing cattle?

Grassland management impacts ecosystem functioning and is critical for livestock production and biodiversity conservation. Decreasing the stocking rate usually benefits biodiversity but also decreases production per unit area. Here, we assessed the combined effects of cattle herd and pasture size on sward structure, diet quality and daily grazing time while maintaining a constant stocking rate. The experiment was conducted over four successive years in two blocks of a species-rich upland grassland that was continuously grazed for 5 months between May and October. Each block consisted of one 3-ha pasture that was grazed by a group of three heifers, one 9-ha pasture grazed by nine heifers, and one 27-ha pasture grazed by 27 heifers. The grazed patches were discriminated using a mathematical model that for each point gave a probability of being grazed based on sward height and spatial dependence. Heifers created fewer patches and had less control over sward height in the smallest (3-ha) plots, while no difference was found between the 9- and 27-ha plots. The small heifer groups also had the shortest daily grazing time. These observations point out a risk that animal impacts on sward structure could be partly missed in grazing experiments conducted with very small groups. Estimated diet quality was unaffected by pasture size. Patch stability was frequent between two successive years but we observed a decrease in interannual patch stability as time intervals increase. Such observations are useful for calibrating spatial interaction models combining foraging behaviour and vegetation dynamics rules and enhance their predictive ability.     

施用不同pH改良剂对荔枝园酸性土壤性质及荔枝生长的影响

采集华南典型荔枝园酸性土壤[pH(4.2±0.2)],分别在土壤中添加石灰（1 g/kg）、白云石粉（2 g/kg）和2个用量（0.625、4 g/kg）钙镁磷肥,以不添加改良剂为对照,进行土壤培养和荔枝盆栽试验,比较不同物质改良土壤的效果及对荔枝生长的影响。结果表明：施用pH改良剂均可不同程度提高土壤pH,影响土壤的大、中、微量元素养分有效性和酶的活性,土壤性质的变化与改良剂种类、用量及土壤属性本身有关;施用石灰、白云石粉和高量钙镁磷肥均能显著促进荔枝生长,其中石灰和白云石粉的综合作用优于高量钙镁磷肥,但施用低量钙镁磷肥抑制荔枝生长。建议石灰和白云石粉可用作荔枝园酸性土壤pH 改良剂,可否选用钙镁磷肥及其合理用量,则需根据土壤性质而定。     

Field indicators of leaf nutritive value for perennial ryegrass and tall fescue pastures under different growing and management conditions

Field indicators of forage nutritive value could help farmers with rapid management decisions to optimize timing and intensity of grazing and meet objectives regarding animal nutrition. The objective of this research was to evaluate the likely relationships among leaf blade nutritive value, herbage mass and leaf stage of pasture regrowth under different growing seasons and residual sward heights. Experiments were performed on perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.) pastures during spring and summer of 2016. In both pastures, three residual sward height treatments (3, 6 and 12 cm) were imposed on plots arranged in a split plot design, replicated in three blocks. Sward plots were harvested 5–6 times at intervals spaced 7–10 days apart to measure herbage mass, plant morphology, neutral detergent fibre (NDF), and the 24-hr in vitro digestibility of NDF (NDFD) and dry matter (DMD) of leaf blades. Pastures showed strong (R²: .62 to .70), but variable, negative relationships between NDFD and herbage mass that varied with the rate at which pasture grew in each season of experimentation. Although there was a consistent NDFD decline as leaf stage of regrowth progressed (R²: .75 to .97), the NDFD also decreased as residual sward height increased, most notably in tall fescue. Additionally, findings indicate that the greater leaf length plasticity of tall fescue compared to residual sward heights may offer opportunities to manage both post- and pre-grazing targets to achieve tall fescue forages with a similar high nutritive value as perennial ryegrass. However, the evaluation of this hypothesis at the farm level and its impacts on animal intake and performance warrants further careful investigations.     

臭氧技术及臭氧植保机械在农业中的应用

随着农药替代技术的发展,以臭氧及臭氧水为代表的臭氧植保技术逐渐在现代生态农业领域得到广泛应用。在介绍臭氧杀虫灭菌机理的基础上,系统阐述了臭氧技术在土壤熏蒸、作物病虫害防治、种子处理、果蔬贮藏、牧场消毒除臭等农业生产领域的应用;在介绍背负式臭氧植保机械、固定式臭氧植保机械、自走式臭氧植保机械、臭氧植保飞机等臭氧相关植保机械的研究及应用现状基础上,剖析了臭氧技术在农业领域的应用优势及制约因素,最后展望了臭氧技术的应用及推广前景。对于进一步研制开发新型臭氧植保机械,并拓展其在农业生产上的应用具有一定的指导意义。