Effects of Mowing Stubbles and Mowing Stages on Nutrient Contents of Forage Mulberry

[Objective]The paper was to study the effects of mowing on nutrients of forage mulberry.[Method]With forage mulberry as the research object,the effects of mowing stubbles and mowing stages on nutrient content of forage mulberry were studied.[Result]With the increase of mowing frequency,the crude protein and crude ash content of forage mulberry decreased,but the crude fiber content increased,and the quality of forage mulberry decreased correspondingly.The crude protein content decreased most obviously from 25.78%in the first stubble to 21.63%in the third stubble.In the first and third stubble,the nutrients at 28±1 d after the last mowing were higher than that at 38±1 d after the last mowing.That is,with the growth of forage mulberry,the accumulated nutrients were also used for their own growth.[Conclusion]From the perspective of nutrient content,the forage mulberry mowed earlier has higher nutritional value and better palatability.

Do mowing regimes affect plant and soil biological activity in the mountain meadows of Southern Poland?

The soil biological activity of mountain meadows is a significant factor that determines the health and utility of these regions. The climax stage of this area is forest, but to maintain semi-natural grassland, which is characterised by high biodiversity,low-intensity land use(mowing or grazing) is necessarily required. To understand the effect of various mowing regimes on the soil biological activity and plants, the soil microbial activity(microbial biomass carbon, dehydrogenase activity and number of the cultivable fraction of soil microbial community),annelids community(density and species composition earthworms and enchytraeids) and plant species composition were investigated. The study area was located in the Pieniny National Park in the Carpathian Mountains, in a meadow belonging to the association Dactylis glomerata-Poa trivialis. The investigated variants were divided according to mowing regime:traditional scything – hand mowing(HM), mechanical mowing(MM), or the abandonment of mowing – nonmowing(NM). The microbial activities(expressed by,e.g. microbial biomass carbon and the number of phosphorus bacteria) were affected by the mowing regime. The density of earthworms was higher in the HM and MM than in the NM variants. The largest changes in plant species composition were caused by the abandonment of mowing(NM). The mean number of plant species was positively correlated with soil moisture, earthworm density, and microbial activity(expressed indirectly by dehydrogenases activity). The soil microbial community, such as vegetative bacteria forms and ammonifying bacteria,were positively associated with pH value, and the microbial and total organic carbon content. The results presented here indicate that there is no single form of optimal management for all living organisms.Decisions about mowing regimes, or abandonment of use, should be preceded by multi-aspect studies,including plants and soil biota.

Effects of Mowing Heights on N₂O Emission from Temperate Grasslands in Inner Mongolia, Northern China

Grazing and mowing are two common practices for grassland management. Mowing is now recommended as an alternative to the traditional grazing for grassland conservation in Inner Mongolia, northern China. Many studies have revealed that mowing may alter ecosystem properties in various ways. However, little attention has been paid to the effect of mowing on trace gas emissions, especially on N2O flux. We conducted an experiment to investigate the effects of mowing on N2O fluxes from the semiarid grassland in Inner Mongolia. The mowing experiment, which started in 2003, comprised four mowing intensity treatments, i.e. mowing heights at 2 cm, 5 cm, 10 cm and 15 cm above the soil surface, respectively, and a control (non-mowing), with five replicates. Gas fluxes were measured through a closed static chamber technique during the growing seasons (usually from May to September, depending on local climate at the time) of 2008 and 2009, respectively. Our results showed that mowing decreased N2O emissions, above-ground biomass and total litter production. N2O emissions were greater in May and June than in other sampling periods, regardless of treatments (P 2O fluxes were mainly driven by variations in soil moisture, except in July and August. In July and August, above-ground plant biomass and soil total nitrogen became the major drivers of N2O fluxes under the soil temperatures between 16 ° C and 18 ° C. Though there were some uncertainties due to the low frequency of N2O flux measurement, our study mainly indicated that 5 cm mowing height might decrease N2O emissions in grasslands during the growing season, and soil properties affected the magnitude of the reduction.

Rapid loss of leguminous species in the semi-arid grasslands of northern China under climate change and mowing from 1982 to 2011

Effects of mowing on the composition and diversity of grasslands varied with climate change(e.g.,precipitation and temperature).However,the interactive effects of long-term mowing and climate change on the diversity and stability of leguminous and non-leguminous species in the semi-arid grasslands are largely unknown.Here,we used in situ monitoring data from 1982 to 2011 to examine the effects of continuous mowing and climate change on the plant biomass and diversity of leguminous and non-leguminous species,and soil total nitrogen in the typical semi-arid grasslands of northern China.Results showed that the biomass and diversity of leguminous species significantly decreased with the increasing in the biomass and diversity of non-leguminous species during the 30-a period.Variations in biomass were mainly affected by the long-term mowing,while variations in diversity were mainly explained by the climate change.Moreover,the normalized change rates of diversity in leguminous species were significantly higher than those in non-leguminous species.Mowing and temperature together contributed to the diversity changes of leguminous species,with mowing accounting for 50.0%and temperature 28.0%.Temporal stability of leguminous species was substantially lower than that of non-leguminous species.Consequently,soil total nitrogen decreased in the 2000s compared with the 1980s.These findings demonstrated that leguminous species were more sensitive to the long-term mowing and climate change than non-leguminous species in the semi-arid grasslands.Thus,reseeding appropriate leguminous plants when mowing in the semi-arid grasslands may be a better strategy to improve nitrogen levels of grassland ecosystems and maintain ecosystem biodiversity.

Study on Weather Forecast Indicators during Mowing Grass Periods in Inner Mongolia

Based on ground observation and remote sensing monitoring data,regions appropriate for mowing herbage in the dog days and autumn were predicted and assessed quantitatively,and regions appropriate for mowing herbage were divided into comparatively suitable,suitable and optimum areas for mowing herbage. Servicing products can be spread to agricultural and pastoral areas via short message service,broadcasting,radio and network in time,and good service effect can be obtained. However,under the effect of precision rate of medium-term prediction areas,the prediction of some rainfall areas deviates from the actual rainfall areas. After timely correction of weather prediction in 24 and 48 hours,pastoral weather forecast service in mowing herbage regions is improved obviously. Herbage mowed in the dog days is rich in nutrients,but it is rainy in the period,which brings certain difficulties to herbage mowing and airing. Therefore,herdsmen in various regions should pay more attention to local weather prediction and regulate mowing herbage periods in time,and autumn herbage can be mowed if the weather is not suitable for mowing herbage in the dog days.

Mowing Height and Mowing Frequency Interactions on Turf Performance of Kentucky Bluegrass

The mowing height and mowing frequency are the key factors that affect the turf quality and turfgrass growing ability. The purpose of this study was to reveal the alternative efficient interaction between mowing height and mowing frequency in Kentucky bluegrass turf management. The Kentucky bluegrass cultivar 'Kenblue'(Poa pratensis L.) was used to evaluate the interactions of mowing heights(H1, H4 and H7) and mowing frequencies(F2, F5 and F8) on the performance of turfgrass and turf physiological responses under the field condition. The results showed that the treatment of H7×F8 had perfect influence on the turf texture, root elongation, and also enhanced soluble sugar and free proline content in plants. While, the turf quality, color, uniformity and the increasing tiller numbers were performed more superior in the treatment of H4×F5 than other treatments. In all the interacting treatments, the relation between leaf green index and number of shoots(dm^2) was positively correlated, thus, it could be speculated that the proper mowing height with frequency had a strong impact on the increasing of turfgrass tillers. On the whole, the interaction of H4×F5 on turf quality was the most excellent treatment in this experiment.

Ecological Planning of Spartina alterniflora Invaded Tideland Based on Mechanical Mowing and Hydraulic Reclamation: A Case Study of Xihu Port in Xiangshan County

Spartina alterniflora is a major invasive plant in the coastal tideland of China that has serious negative impact on local economy and ecology.This paper took Hugang New Town in Xiangshan County,Zhejiang Province for example,concluded the method of controlling S.alterniflora by integrating mechanical mowing and hydraulic reclamation in view of the threatening expansion of this species and serious land shortage in the local area.Moreover,it explored the ecological planning method of reclamation area based on this method.In view of the ecological sensitivity of the reclamation area,urban ecological planning concept was introduced into both processes of the development:penetrative reclamation and urban planning.The reclamation project has to meet such requirements as site selection,scope,water surface ratio etc.,the planning ensures the ecological sustainability in functional orientation,spatial structure,green space system and development intensity.

The Effects of Ground Cover Mowing Height on the Fauna of Ground-dwelling Arthropods in Olive Grove

Ground dwelling insects,spiders,and other arthropods play an important role in agroecosystems as predators and saprophytic organisms.Their presence on the soil surface helps the biological control of pests,enhances organic matter decomposition and promotes biodiversity.Soil disturbance,particularly tilling and mowing has greatly affected the assemblage and abundance of epigeic arthropods.This study aimed to determine the effects of herbaceous vegetation cover mowing height on arthropods abundance and structure in olive orchards.The experimental site was divided into three zones(Z1,Z2,and Z3)regarding mowing heights(0 cm,10 cm,and 15 cm).This research was done in 2019 from the beginning of May untill the end of September.During this research,1490 individuals were recorded belonging to 6 classes,11 orders and 13 families.The number of individuals was higher in the zones Z2 and Z3 comparing with Z1.The highest number of individuals showed woodlices(Isopoda)comprising 67,5%of all individuals collected.There were significant differences in the number of Carabidae,Bleteliidae and Forficulidae between the zones of research.Unlike Forficulidae,higher heights of mown positively affected the population of Carabidae and Blateliidae.

Effects of mowing and nitrogen addition on soil respiration in three patches in an oldfield grassland in Inner Mongolia

Aims Vegetation type is important in determining variations in soil carbon(C)efflux under grassland managements.This study was conducted to examine the effects of mowing and nitrogen(N)addition on soil respiration and their dependences upon vegetation types in an oldfield grassland of northern China.Methods Soil respiration,temperature,moisture and aboveground net primary productivity(ANPP)and belowground net primary productivity(BNPP)were examined in response to mowing and N addition among the three patches dominated by different species(named as grass,forb and mixed patches,respectively)in the growing seasons(May–October)from 2006 to 2008.Important Findings Across the 3 years,soil respiration in the grass patch was greater than those in the forb and mixed patches,which could have been ascribed to the higher soil moisture(SM)in the grass patch.Mowing had no impact on soil respiration due to unaltered SM and plant growth.Soil respiration was stimulated by 6.53%under N addition,and the enhancement was statistically significant in 2006 but not in 2007 or 2008 because of the limited water availability in the later 2 years.There were no interactive effects between mowing and N addition on soil respiration.Soil respiration showed positive dependence upon SM,ANPP and BNPP across plots.The results suggest that soil water availability and plant growth could be the primary factors in controlling the temporal and spatial variations in soil respiration and its response to different treatments.Our observations indicate that grassland managements(i.e.mowing for hay once a year)may have little influence on soil respiration of the oldfield grassland in northern China.

Contrasting effects of N fertilization and mowing on ecosystem multifunctionality in a meadow steppe

There is little experimental field evidence on how multiple essential land use intensification drivers(LUIDs),such as nitrogen(N)fertilization and mowing,interact to control ecosystem multifunctionality.Here,we conducted a 4-year field experiment in a meadow steppe in northeast China and evaluated the direct and indirect effects of mowing and N fertilization on a range of ecosystemfunctions associated with nutrient cycle,carbon stocks,and organic matter decomposition during the past 2 years of the experiment(2017 and 2018).Mowing had negative effects on the ecosystem multifunctionality index(EMF),carbon(C)cycle multifunctionality index(CCMF),and N cycle multifunctionality index(NCMF)in 2 years of sampling.However,in general,the responses of multifunctionality to N fertilization were ratespecific and year-dependent.N fertilization had positive effects on EMF,CCMF,NCMF,and phosphorus(P)cycle multifunctionality index(PCMF)in 2017,with the higher precipitation rate during the growing season,which was likely associated with the strong monsoon season.However,in 2018,EMF,CCMF,and NCMF increased at the lower N fertilization levels(£10 g N m^(-2) yr^(-1)),but decreased at higher N rates.N fertilization had consistent positive effects on PCMF in the 2 years of sampling.The effects of land use drivers on multifunctionality were indirectly influenced by bacterial biomass,plant richness,and soil moisture changes.Our results also indicated that the impacts of land use drivers on multifunctionality played an important role in maintaining a range of functions at low levels of functioning(<50% functional threshold).Low N fertilization levels(£10 g N m^(-2) yr^(-1))were able to reduce the negative effects of mowing on ecosystem multifunctionality while promoting plant biomass(food for livestock)and C storage.These findings are useful for designing practical strategies toward promoting multifunctionality by managing multiple LUIDs in a meadow steppe.

混合办公废纸(MOW)脱墨技术研究

2021年国内废纸回收量达到6491万吨,而多年来废纸回收率仍低于其他发达国家回收率,因此,提高废纸回收率迫在眉睫。混合办公废纸(MOW)占可回收废纸总量70%~80%,回收较为困难,其中脱墨就是极为关键的第一步。本研究综述了MOW的基本性质、对比不同MOW脱墨技术以及对未来研究进行展望,以期能为MOW的脱墨技术的发展提供参考。

15Cr2Ni3MoW钢穿孔顶头的失效分析及改进

介绍了15Cr2Ni3MoW钢穿孔顶头在穿制27SiMn钢时发生的主要失效形式。对比了成品顶头和失效顶头的金相组织和显微硬度;利用Gleeble-1500型热模拟机对比了27SiMn钢和20钢在穿制温度下的变形抗力;通过扫描电镜和能谱分析研究了成品顶头表面氧化膜。结果表明:27SiMn钢在穿制温度下变形抗力大,钢中Si含量高,顶头工作温度高,顶头表面氧化膜组织疏松以及在顶头表面氧化膜下面存在一层粗大的铁素体软区,是造成顶头失效的主要原因。提出了提高穿孔顶头使用寿命的措施。

15Cr2Ni3MoW钢管穿孔顶头氧化膜制备工艺的研究

研究了15Cr2Ni3MoW合金穿孔顶头在900～1000℃、3～12 h、氧气气氛中氧化膜的生成行为。用OM、XRD、SEM、HV分析研究氧化膜的微观组织形貌、相组成及显微硬度的变化,并对氧化膜生成机理进行探讨。结果表明:在氧气气氛中合金生成内外两层氧化膜,外层氧化膜主要为Fe2O3和Fe3O4,内层氧化膜主要为(Fe、Cr)3O4;随氧化时间延长和氧化温度升高,氧化膜厚度不断增加,但内层与外层氧化膜之间的结合力以及内层氧化膜与顶头基体之间的结合力,不随氧化膜厚度的增加而增大,当氧化时间和温度超过个某个范围后,所生成氧化膜间的结合力反而降低。

20CrNi3MoW穿孔顶头组织分析

对20CrNi3MoW钢穿孔顶头的显微组织和硬度变化进行了研究。结果表明,顶头原始组织为粒状贝氏体组织,同时夹杂部分隐针马氏体和残余奥氏体;经正火处理后顶头组织改善,性能提升。顶头表面氧化膜应均匀、致密,因此应合理控制氧化条件,得到尽可能多的FeO层。最后结合生产实际提出了改进措施。

阳离子分散松香胶的制备及其在MOW脱墨浆中的应用

以乙醇为介质,用三乙胺、环氧氯丙烷和松香合成阳离子松香型乳化剂,用该乳化剂与阳离子和非离子表面活性剂复配作为乳化剂,采用常压逆转法可以制得性能稳定的阳离子分散松香胶。该施胶剂用于MOW脱墨浆时,在施胶剂用量1.5%、硫酸铝用量1.5%、pH值小于7时,具有较理想的施胶效果,能够实现近中性施胶,但对纸页的物理强度(抗张强度、撕裂强度、耐破度)有一定的负面影响。

混合办公废纸浮选脱墨工艺优化

研究碎浆时间、温度、浓度和碎浆机转速以及药品用量对办公废纸(MOW)浮选脱墨效果的影响。结果表明:在碎浆时加入脱墨化学品对提高白度、脱墨效率都非常重要;在优化碎浆和浮选的条件下,经一段浮选MOW脱墨浆的白度可以从77.5%ISO提高到84.8%ISO,残余油墨可由228.2mg·L-1下降到17.8mg·L-1。在此基础上,还探讨了研制的脱墨剂泡沫形成和破裂速度对浮选脱墨的影响。

生物酶法脱墨在MOW中的研究进展

混合办公废纸(MOW)已成为重要的造纸纤维来源,利用生物酶法脱墨对MOW脱墨是一种新的造纸技术。酶法脱墨在MOW中的使用主要包括纤维素酶、淀粉酶、脂肪酶,多组分复合使用协同作用更佳,本文主要就国内外生物酶法脱墨在MOW中的研究进展和脱墨机理作一报道,并对酶法脱墨的问题和前景作一浅析。

Canada Thistle (Cirsium arvense) Response to Clipping and Seeding of Competitive Grasses

Chemical restrictions, ecological concerns, liability issues, and public sentiment present challenges to land managers attempting to control highly invasive plants like Canada thistle (Cirsium arvense [L.] Scop.). Although herbicide application can be an effective control strategy, increasing limitations force managers of sensitive environments (e.g., national parks, wildlife refuges, protected water-bodies or waterways) to search for effective control alternatives. A greenhouse study was conducted to test the effectiveness of clipping (to simulate field mowing) and grass seeding as alternatives for Canada thistle control. Two native North American grasses (western wheatgrass [Pascopyrum smithii {Rydb.} A. L?ve] and streambank wheatgrass [Elymus lanceolatus {Scribn. & J.G. Sm.}Gould ssp. lanceolatus]) and one sterile hybrid cross between common wheat (Triticum aestivum L.) and tall wheatgrass (Thinopyrum ponticum [Podp.] Z.W. Liu & R.C. Wang) called RegreenTM were used. The effects of clipping and grass seeding on Canada thistle growth, and the effect of Canada thistle on grass growth, were evaluated using 14 unique treatments applied to potted Canada thistle and grass plants. Clipping inhibited Canada thistle growth (by 60%), while grass seeding had no effect. Presence of Canada thistle inhibited grass growth for all seeding treatments except when RegreenTM and western wheatgrass were seeded together with Canada thistle. Planting multiple species for restoration of Canada thistle-infested sites may be important (RegreenTM + western wheatgrass treatment), and cutting Canada thistle may be useful for reducing its growth in restored areas.

Nutrient Release during Residue Decomposition of Weeds Mown at Different Times in a Persimmon Orchard

Decomposition and nutrient release of the residue subsequent to mowing weeds remain poorly understood in persimmon orchards of South Korea. The litterbags including various weed residues were deposited on the soil surface under the tree canopy to simulate the fate of weeds mowed on 13 May, 13 July, and 13 September 2011 and 2012. Rate of decomposition and nutrient release of the residues depended on different mowing times. Residual dry mass (DM) of the 13 May weeds decreased by 17% - 21% of initial DM during 1 month and by 63% -71% until 2 months after litterbag deposition, and they?released 51% - 67% of nitrogen (N), 54% - 55% of phosphorus (P), and 92% - 94% of potassium (K) of respective initial amount until the first 2 months. The 13?July weeds rapidly decomposed during the first month, accounting for 51% - 64% of DM and released 49% - 67% of N, 27% - 54% of P, and 76% - 77% of K. When mowed on 13 September, the weed residue decomposed slower and?longer than the 13 May and 13 July weeds, losing 48% - 51% of DM, 36% - 39% of N, 60% - 64% of P, and 70% -77% of K during the first 2 months but continuing an active decomposition even at 6 months after the deposition. The results indicated that time of supplemental fertilization should be adjusted depending on mowing times, and the mowing times be controlled to meet seasonal demand of persimmon trees for nutrients.

采用不同方法预测10Cr9MoW2VNbBN钢蠕变曲线的比较

采用θ投影法和自行建立的复合修正模型对10Cr9MoW2VNbBN钢的蠕变曲线进行了预测,并与600℃和650℃时的蠕变试验数据进行了对比。结果表明:θ投影法能较好地描述蠕变应变与时间的关系,但对蠕变速率与时间的关系不能客观描述;自行建立的复合修正模型能够更客观地描述试验钢真实的蠕变行为;但基于复合修正模型的蠕变曲线结合断裂应变进行持久寿命外推时,其外推值高于真实值。