Effects of Planting Density and Row Spacing on Grass Yield of Forage Sweet Sorghum(Sorghum bicolor [L.]Moench)

[Objective] The aim was to explore high-yielding cultivation techniques for forage sweet sorghum. [Method[ The effects of planting density and row spacing on plant productivity and grass yield of forage sweet sorghum （Sorghum bicolor （L.） Moench） were compared using split-plot design and LSD method of IBMSPSSStatis- ticsv22. [Result]The planting density and row spacing had important influence on the plant productivity and yield of forage sweet sorghum. The optimum planting density- row spacing combination for plant productivity of forage sweet sorghum was A1B,, i. e., planting density of 75 000 plants/hm2 and row spacing of 40 cm, and the opti- mum combination for yield of forage sweet sorghum was A2B,, i.e., planting density of 225 000 plants/hm2 and row spacing of 40 cm. [Conclusion] This study will pro- vide theoretical basis and technical support for the production practice of forage sweet sorghum.

Study on the Relationship of Seedling Density and Line Spacing to Leaf-stem Ratio, DW/FW Ratio and Grass Yield of Forage Sweet Sorghum

[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.

Modeling grass yields in Qinghai Province,China,based on MODIS NDVI data--an empirical comparison

Qinghai Province is one of the four largest pastoral regions in China.Timely monitoring of grass growth and accurate estimation of grass yields are essential for its ecological protection and sustainable development.To estimate grass yields in Qinghai,we used the normalized difference vegetation index(NDVI)time-series data derived from the Moderate-resolution Imaging Spectroradiometer(MODIS)and a pre-existing grassland type map.We developed five estimation approaches to quantify the overall accuracy by combining four data pre-processing techniques(original,Savitzky-Golay(SG),Asymmetry Gaussian(AG)and Double Logistic(DL)),three metrics derived from NDVI time series(VImax,VIseason and VImean)and four fitting functions(linear,second-degree polynomial,power function,and exponential function).The five approaches were investigated in terms of overall accuracy based on 556 ground survey samples in 2016.After assessment and evaluation,we applied the best estimation model in each approach to map the fresh grass yields over the entire Qinghai Province in 2016.Results indicated that:1)For sample estimation,the crossvalidated overall accuracies increased with the increasing flexibility in the chosen fitting variables,and the best estimation accuracy was obtained by the so called“fully flexible model”with R2 of 0.57 and RMSE of 1140 kg/ha.2)Exponential models generally outperformed linear and power models.3)Although overall similar,strong local discrepancies were identified between the grass yield maps derived from the five approaches.In particular,the two most flexible modeling approaches were too sensitive to errors in the pre-existing grassland type map.This led to locally strong overestimations in the modeled grass yields.

Effects of Mixture Sowing on Forage Yield and Interspecific Competition of Alfalfa and Orchard Grass

[ Objective] To explore the mixture sowing effects and optimal mixture ratio of alfalfa and orchard grass. [ Method] The alfalfa and orchard grass were sowed at different ratios （1 ： 0, 3： 1, 1 ： 1, 1 ： 3 and 0：1 ）. They were grouped and named as CK1, A1, A2, A3 and CK2., respectively. The forage yield, relative yield total （RYT） and the competition rate （CR） of alfalfa and orchard grass in each group were determined, respectively. [ Result] In the A3 treatment group, the total forage yield was the highest （4 827.67 kg/hm2） and significantly different from that of other treatment groups （ P 〈 0.01 ）. In every treatment group, the RYT was higher than 1, and the alfalfa was more competitive than the orchard grass in the mixed-seeding pasture. [ Conclusion] Our studies may provide a basis for the establishment of high yield and high quality artificial mixture pasture.

Effect of Autumn Cutting Date on Regrowth, Turning Green, Yield and Quality of <i>Leymus chinensis</i>Grassland in Songnen Plain, Northeast China

A field study was carried out to quantify the effects of different cutting time on Leymus chinensis population and community characteristic in Songnen grassland of northeast China from August, 2006 to August, 2007. The treatment interval was ten days with the remaining stubble height of 5 cm from 15th August to 4th October in 2006. Results showed that the L. chinensis made up about 90% of the dry matter of aboveground biomass, and there were about ten species in the L. chinensis community in the 1 m × 1 m plot. The L. chinensis and Kalimeris integrifolia regrew rapidly after autumn cutting in 2016. In the second year, the coefficients of the community similarity were high between the different cutting time treatments. The density, height, aboveground biomass, stem/leaf ratio, and crude protein of L. chinensis were not significant at the turning green stage and harvesting stage, the companion species of L. chinensis community contained higher crude protein, but the crude protein of the plant community were not significant. Thus, considering the weather factor for haymaking, the harvest dates should be concentrated from the middle ten days of August to the first ten days in September.

Effect of grass coverage on sediment yield in the hillslope-gully side erosion system

By scouring experiments, the changeable process and characteristics of sediment yield in the hillslope-gully side erosion system with different coverage degrees and spatial locations of grass were studied. Five grass coverage degrees of 0, 30%, 50%, 70%, 90%, three spatial locations of grass （upslope, mid-slope, low-slope） and two water inflow rates of 3.2 L/min, 5.2 L/min were applied to a 0.5 by 7 m soil bed in scouring experiments. Results showed that the sediment yield decreased with the increase of grass coverage degree at 3.2 L/min water inflow rate in scouring experiments and the sediment yield with different grass locations on the sloping surface was in the order of upper 〉 middle 〉 lower. At 5.2 L/min water inflow rate, the differences of sediment yield among various grass coverage degrees were increased, whereas the changeable tendency of sediment yield with different grass locations on the whole sloping surface was not very obvious. The proportion of sediment yield from the gully side increased in an exponential relationship with the increase of grass coverage degree When the grass was located on the lower position of hillslope, the influence for accelerating gully erosion is the greatest.

Quantifying Tillage and Vetiver Grass (Vetiveria nigritana Stapf) Strips Spacing Effects on Runoff, Soil Loss and Maize Yield in Southern Guinea Savanna of Nigeria

Soil erosion induced by inappropriate tillage remains a serious problem on many agricultural fields in the humid tropics. Studies were conducted between 2004 and 2006, on an Alfisol in Ogbomoso in the Southern Guinea Savanna of Nigeria to evaluate the effectiveness of Vetiver Grass(Vetiveria nigritana) Strips(VGS) under different tillage systems. The experiment was split-plot laid out in a randomized complete block design with two replications on 6% slope with 18 runoff plots. Main plot treatments were tillage systems; Manual Clearing(MC), Ploughing(P) and Ploughing plus Harrowing(PH). Subplot treatments were VGS spaced at intervals of 5 m(eight strips) and 10 m(four strips) with the control(no-vetiver). Runoffs and soil losses were collected after each major storm. Chemical analyses of eroded sediments and runoff were determined. Data were analyzed using ANOVA at p<0.05. The results showed that tillage had no significant reduction in runoffs and soil losses, but they were reduced with MC compared with P and PH. Mean total runoff on 5 and 10 m VGS plots were significantly(p<0.05) lower than that of the control by 74.4% and 45.0%, respectively. Corresponding soils loss on 5 and 10 m VGS plots were 27.1% and 53.5%, respectively. Mean NO3-N levels in runoff water were lower under PH plots than those under MC plots by 79.0% and 66.5%, respectively in 2004 and 2006 growing seasons. VGS spaced at 5 m significantly(p<0.05) reduced NO3-N loss than the control by 108.8% in 2004. Nutrients loads of eroded sediments were consistently higher for the control(no-vetiver) plots and least for 5 m VGS plot. Carbon, nitrogen and phosphorus contents of eroded sediments were 90%-92.4%, 83%-83.6% and 97%-97.8%, respectively, and were lower on 5 m than other treatments. Maize grain yield was significantly(p<0.05) affected by both tillage and VGS spacing only in 2005 growing season. P plot produced higher grain yield than MC and PH by 79.9% and 99.1%, respectively. Also, grain yield on VGS plot was significantly(p<0.05) higher on 5 and 10 m VGS plots than the control by 82.2% and 85.4%, respectively. The significant beneficial effect of PH in producing higher yields was dwarfed by the potential danger of soil erosion in the absence of a soil erosion control measure. The results showed that a balance needed to be struck between mechanical clearance and protective measure against soil erosion.

Effect of grass density and date of tapping on Acacia senegal gum yield in north kordofan state, Sudan

We conducted a two-factor experiment in randomized complete block design with four replications during 2004 in El Demokeya Forest Reserve and El Himaira Natural Forest, North Kordofan State, Sudan. The objective was to develop an understanding of the ecological effects of under-story vegetation and tapping date on the productivity of gum arabic from Acacia senegal as over story cover. The first factor was grass cover which was tested in four levels （100% and 50% grass cover in addition to bare and burnt）. The second factor, date of tapping was tested in three levels namely （1st Oct, 15th Oct and 1st Nov）. The first picking was done after 45 days from tapping and the gum yield up to seven pickings was collected at intervals of 15 days. Gum yield from each picking was collected and weighed using sensitive balance. Analysis of variance was carried out using MSTAT-C statistical package, and the Tukey test was applied for mean comparisons. The results showed highly significant differences （p 〈 0.01） of grass cover on gum arabic yield in the two sites for most of the first consecutive pickings （1st–4th out of seven） in addition to total yield （kg/ha）. With exception to the 4th pickings, the interaction effect between the grass densities and tapping date was not significantly different. The total gum yield was significantly （p 〈 0.05） increased in only two pickings （third and fourth） in El Demokeya Forest Reserve and two pickings （1st and 2nd） at El Himaira Natural Forest. The density of grass cover significantly （p 〈 0.05） affected the number of pickings at both sites; the number of gum pickings was directly proportional to grass density. The number of gum pickings was found to be significantly （p 〈 0.05） increased at the early date of tapping.

The Effect of Organo-Mineral Fertilizer Applications on the Yield of Winter Wheat, Spring Barley, Forage Maize and Grass Cut for Silage

Biosolids were applied with urea to produce a granulated organo-mineral fertiliser (OMF) for application by farm fertiliser equipment to a range of agricultural crops. The recommended rates of nitrogen, phosphate and potash were calculated for the test crops using “The Fertiliser Manual”, which assesses the nutrient requirement based on previous cropping, rainfall and soil index. The OMF produced similar crop yields compared to ammonium nitrate fertiliser when applied as a top-dressing to winter wheat, forage maize and grass cut for silage in the cropping years 2010 to 2014. In 2012 the grain yield of spring barley top-dressed with OMF was significantly lower than the conventional fertiliser treatment, due to dry conditions following application. For this reason it is recommended that OMF is incorporated into the seedbed for spring sown crops and The Safe Sludge Matrix guidelines followed. The experimental work presented shows that OMF can be used in sustainable crop production systems as a source of nitrogen and phosphorus for a range of agricultural crops.

Study on the Influence of Climatic Change on Pasture Growth in Inner Mongolia Grassland

Through analyzing statistically metrological observation data from 1971 to 2010 and pasture data from 1983 to 2012 at 6 animal husbandry meteorological testing stations of Inner Mongolia grassland, the conclusions were drawn. Those were that annual average temperature rose in a straight line in Inner Mongolia grassland, and the increase rates of annual average temperature in meadow steppe and typical steppe were 0.40 and 0.34 ℃/10 a respectively. Annual rainfall had 10-year cyclical characteristics, and precipitation in the 1990s was the most but reduced significantly after 2000. Climate experienced the cold wet -cold dry -warm wet -warm dry periods. Warm and dry climate made the average heights of pasture in meadow steppe and typical steppe of Inner Mongolia cut down 2.4 and 9.3 cm in nearly 12 years than that in the 1990s; the average coverage of herbage decreased by 11% and 13%; the average hay yields reduced by 1 019.8 and 671.4 kg/hm^2.

天山北坡平原荒漠灌区9个紫花苜蓿品种生产性能综合评价

【目的】筛选出适宜在天山北坡平原荒漠区推广种植的紫花苜蓿品种。【方法】采用单因素随机区组设计,测定9个紫花苜蓿品种的株高、草产量、品质等指标,并利用灰色关联法对9个品种进行综合评价。【结果】随种植年限增加,供试材料的鲜草和干草产量均呈下降趋势,其中第1年的干草产量占比较高,平均为37.77%;佰苜341的株高积累量最大,为939.8 cm,显著高于其他品种;骑士T干草总产量、粗蛋白含量和相对饲喂价值最高,分别为61602.03 kg/hm^(2)、16.83%和119.16%;灰色关联度综合评价结果由高到低的顺序为:骑士T>佰苜202>大银河>阿迪娜>佰苜341>佰苜371>挑战者>佰苜401>康赛。【结论】骑士T的综合表现较好,建议在天山北坡平原荒漠灌区引种种植。

苜蓿混播方式及比例对混播草地生产力和稳定性的影响

为了探究适合科尔沁沙地的禾豆混播模式,将紫花苜蓿按8个水平(占单播量的5%,10%,15%,20%,25%,30%,35%,40%,B_(1)~B_(8))和2种方式(间行A_(1)和交叉A_(2))混播到2月龄的无芒雀麦草地,分析混播方式与混播比例对禾豆混播草地生产力和群落稳定性的影响。结果表明:混播方式对第3茬无芒雀麦产量影响显著,A_(2)处理显著高于A_(1)(P<0.05)。A_(1)处理1~3茬及全年苜蓿产量均高于A_(2),其中第3茬及全年苜蓿产量差异显著(P<0.05)。禾豆总产量除2茬A_(1)显著高于A_(2)(P<0.05)外,其余无显著差异。A_(2)处理2、3茬无芒雀麦相对密度(RD)和3茬相对产量(RY)显著高于A_(1)。苜蓿混播方式对各茬苜蓿RD和RY没有显著影响,而对全年苜蓿RY影响显著,A_(1)显著高于A_(2)(P<0.05)。A_(1)处理2茬及全年相对产量总和(RYT)显著大于A_(2)(P<0.05)。随着苜蓿混播比例增加,全年苜蓿产量、禾豆产量和RYT呈增长趋势,而无芒雀麦产量、无芒雀麦和苜蓿RD、RY均呈下降趋势。不同苜蓿混播比例下各茬无芒雀麦RY均小于1,而苜蓿RY均大于1。混播处理全年RYT均大于1,混播20%~40%苜蓿第3茬RYT>1。模糊综合评价结果表明A_(2)B_4组合最优,其次是A_(2)B_(3)组合。综合考虑牧草产量和群落稳定性,在固定播量的2月龄无芒雀麦草地上交叉混播15%~20%苜蓿较适宜。

不同密度和施氮量对‘保大麦25号’鲜草和籽粒产量的影响

探索不同用途的‘保大麦25号’最佳播种密度和氮肥用量,为大面积示范推广提供科学依据。以密度和施氮量为试验因素,分别设3个水平,共9个处理,进行密度和施氮量2因素互作试验。结果表明,鲜草产量随着施氮量和密度的增加而增加;随着密度增加而增加,随着施氮量增加至施尿素525 kg/hm^(2),籽粒产量达最大值后开始下降。以收获鲜草为目的,最适密度为基本苗300万株/hm^(2),最佳施氮量为施尿素675 kg/hm^(2)。以收获籽粒为目的,最适密度为基本苗240万株/hm^(2),最佳施氮为施尿素52 kg/hm^(2)。同一处理间,扣除种子、氮肥成本后,收获鲜草比收获籽粒经济效益高810~4540.8元/hm^(2)。

Early Forage Biomass and Sward Structures of Native Warm-Season Grasses Established at Different Seedling Densities

Effects of transplanted seedling density and species on sward structure of native warm-season grass (NWSG) stands were compared in a randomized complete block design. About 6-week-old NWSG (big bluestem (BB, Andropogon gerardii Vitman), eastern gamagrass (GG, Tripsacum dactyloides L.), indiangrass [IG, Sorghastrum nutans (L.) Nash] and switchgrass (SG, Panicum virgatum) seedlings were transplanted in 45-cm wide rows on clean-tilled seedbeds. Within-row spacing was 30, 25, or, 20 cm giving 10, 12, and 15 plants m-2 as low, medium, and high seedling density, respectively. During establishment, the stands were allowed uninterrupted first year growth without fertilizers or irrigation but when necessary, tall-growing broadleaf weeds were mechanically removed. In the following spring, all dead standing biomass was mowed down to allow emerging tillers access to sunlight. During the second year after planting, early-spring basal diameters, row-length intercepted by the NWSG crowns, mid-summer sward heights, and percentage bare ground were determined. From the second June after planting, and for two consecutive years, plots were harvested twice year-1 to assess forage biomass. Data showed that, unlike species, seedling density had no effect on the assessed parameters. Cumulative forage biomass, in kg DM ha-1, was the least for GG (4901) at low and the most (18,245) for SG at high seedling density during the second year. Corresponding values for the third year were 4500 and 7799 kg DM ha-1. Basal diameters ranged from 18 cm (BB) to 24 cm (IG) while percent row intercepts were from 6 (GG) to 46 (IG) with sward heights measuring 41 cm (IG) to 54 cm (GG). In each stand, percent ground cover by the NWSGs, and at every seedling density, averaged 60.5. Transplanting at ≥10 plant m-2 resulted in harvest-ready stands by the second year of establishment. And while close spacing favored the NWSGs against weeds, data showed that an initial plant density of >10 plants m-2 may not result in increased forage production worthy the additional establishment cost. Data on response to fertility management and forage quality attributes are necessary for more reliable practical recommendations.

烯效唑对扁穗雀麦生长发育和种子产量品质的影响

探究烯效唑对扁穗雀麦生长发育和种子产量品质的影响,为其种子增产提质提供科学依据。以‘江夏’扁穗雀麦为试验材料,采取随机区组设计,在拔节期喷施不同浓度烯效唑(0、50、90、130 mg/kg),研究植株生长、种子产量和萌发特性。结果表明:烯效唑降低了植株高度,提高了抗倒伏能力。除50 mg/kg的烯效唑对生殖枝数有显著增加外(P<0.05),其余处理对植株第二节长、茎粗、分蘖数和生殖枝数影响差异不显著。喷施不同浓度烯效唑,扁穗雀麦的小穗数/生殖枝、种子数和种子产量均表现为增加,但只有50 mg/kg处理下各指标差异达显著水平(P<0.05)。90 mg/kg烯效唑处理可显著增加扁穗雀麦种子活力指数(P<0.05),但所有处理对千粒重、发芽率和发芽指数影响较小。各指标相关性分析发现,植株高度与倒伏率、分蘖数和生殖枝数极显著正相关(P<0.01);种子产量和生殖枝数显著正相关(P<0.05)。喷施50 mg/kg烯效唑,扁穗雀麦种子产量最高,达1508.31 kg/hm^(2),较对照增加13.63%,差异显著(P<0.05)。

果园生草条件下苹果病虫害发生特征

为明确宁夏引黄灌区果园优势功能草种类型并进行获益评价,选用黑麦草Lolium perenne、苜蓿Medicago sativa、高羊茅Festuca arundinacea、长柔毛野豌豆Vicia villosa等4种具备潜在绿肥功能的草种以及自然生草进行果园行间长期生草处理,以清耕模式为对照,对生草试验3年后不同功能草种条件下的果树生长发育及主要病虫害发生状况进行调查,解析不同生草品种条件对果园苹果生长发育、产量品质、病虫害发生情况的综合影响。不同草种生草对苹果生长发育及病虫害的影响不同,即人工播种长柔毛野豌豆、高羊茅、黑麦草及自然生草均可促进果树生育与果实产量品质的提升,减少蚜虫、叶螨发生量,增加瓢虫、草蛉的种群数量。人工播种苜蓿则会显著抑制果树的生育,并使斑点落叶病发生率提高37.62%。果树生长发育与病虫害及天敌发生量的相关性分析表明,果树短枝率与捕食性天敌瓢虫发生量呈显著正相关(R^(2)=0.72),单株产量与捕食性天敌瓢虫(R^(2)=0.64)及草蛉(R^(2)=0.57)发生量呈显著正相关,与叶螨、蚜虫、早期落叶病发生量呈显著负相关(0.462<0.77);此外,捕食性天敌草蛉与瓢虫发生量呈显著正相关,瓢虫与叶螨及蚜虫发生量呈显著负相关(R^(2)>0.62)。综上,果园行间播种长柔毛野豌豆能促进果树生长发育,减少病虫害发生,即果树的获益程度最高,具体表现为(相较于清耕):促进果树生长发育方面,可使短枝率提高15.91%,单果重提高12.62%,可溶性固形物含量提高5.95%,可溶性糖含量提高10.54%,可滴定酸含量降低21.43%,使蚜虫发生量降低36.10%,叶螨发生量降低22.46%,可作为宁夏引黄灌区果园的优势功能草种。

青藏高原高寒草地食草家畜碳收支动态

高寒草地生态系统是青藏高原地区主体生态类型,支撑着当地牧民的生活和生产,同时也发挥着维持区域生态安全的重要作用。食草家畜是草地系统和人类社会紧密耦合的重要元素,其碳收支动态成为草地生态系统碳循环中的重要过程之一,但目前对食草家畜的碳收支及其动态并没有得到很好的量化。利用县级统计年鉴数据量化了青藏高原2000—2020年期间的食草家畜碳收支及去向,并与基于卫星遥感的净初级生产力(Net primary productivity,NPP)和可利用产草量(Available grass yield,GYA)进行了对比分析,得到如下结论:(1)2000—2020年期间,青藏高原草地NPP总量和GYA总量分别为(153.88±17.96)Tg C/a和(26.40±3.19)Tg C/a,食草家畜碳摄入量(Intake carbon,IT_(C))为(31.08±0.98)Tg C/a(占GYA总量的118%)。(2)青藏高原草地NPP、GYA、IT_(C)均呈现显著增加趋势,但IT_(C)占GY_(A)的比值呈现显著下降趋势,并且这一比值在空间上存在异质性。(3)食草家畜摄入碳量中有13.24 Tg C/a(约占IT_(C)的43%)通过粪尿排泄排出,12.35 Tg C/a通过呼吸产热排出,0.96 Tg C/a以CH_(4)形式排出,固存在家畜体内的碳是4.53 Tg C/a,而以畜产品向人类社会输出的碳是0.384 Tg C/a。从动物代谢生理层面量化了青藏高原食草家畜碳收支及其时空动态,对草牧业管理、草地碳增汇及全球变化生态学具有重要意义。

甘肃陇中地区中熟早熟青贮玉米品种生产性能研究

【目的】筛选生产性能高、适宜于作为秋播小黑麦复种青贮玉米作物的品种。【方法】研究9个中熟早熟青贮玉米品种(华美2号,利合228,利单656,大京九26,京科青贮932,武科青贮107,西蒙青贮707,豫青贮23,蒙青贮1812)在甘肃中部地区的农艺性状和草产量。【结果】豫青贮23的株高、穗位高和叶片数均表现较好,生长发育较快,2020和2021年的鲜草产量均最高,分别为140.95、79.13 t/hm^(2),达到了青贮玉米的最佳收获期;西蒙青贮707虽叶片数量较少、株高低、叶片较短较宽,但穗上叶数量较多、茎秆较粗,2020年鲜草产量较高,为115.4 t/hm^(2),2021年由于干旱,鲜草产量仅为56.6 t/hm^(2),两年均达到了青贮玉米的最佳收获期。【结论】综合分析参试品种的草产量和生育时期,豫青贮23和西蒙青贮707适宜在甘肃中部地区种植,可作为秋播小黑麦的复种作物。

不同豆禾混播组合在帕米尔高原牧区产草量和营养品质的比较

试验旨在探究豆禾牧草混播组合在帕米尔高原牧区的产草量和营养品质,开展了以箭筈豌豆(Vicia sativa)分别和燕麦(Avena sativa)、小黑麦(Triticale)及黑麦(Secale)的混播组合研究。试验设置单播边锋255 kg/hm^(2)(B-D)、凯速255 kg/hm^(2)(K-D)、速捷255 kg/hm^(2)(S-D)、捷达冬牧70 255 kg/hm^(2)(J-D)、陇箭2号150 kg/hm^(2)(L-D)为对照,混播边锋210 kg/hm^(2)+陇箭2号120 kg/hm^(2)(BL-H)、凯速210 kg/hm^(2)+陇箭2号120 kg/hm^(2)(KL-H)、速捷210 kg/hm^(2)+陇箭2号120 kg/hm^(2)(SL-H)、捷达冬牧70 210 kg/hm^(2)+陇箭2号120 kg/hm^(2)(JL-H)为处理组,试验共9个处理,测定生产性能和营养指标,并运用灰色关联度进行综合评价。结果显示,混播组合中,JL-H总干草产量最高(15.58 t/hm^(2)),极显著高于其他混播组合(P<0.01);SL-H的粗蛋白含量为12.73%,显著高于其他混播组合(P<0.05);混播处理的中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)含量总体低于单播禾草,高于豆草;混播组合中,BL-H的NDF含量和ADF含量最低,分别为56.27%和36.63%。研究表明,SL-H混播组合综合评价值最高(0.218),若兼顾产量和营养品质,SL-H混播组合(速捷210 kg/hm^(2)+陇箭2号120 kg/hm^(2))适合在帕米尔高原牧区种植应用。

2022年7—8月干旱对川西高原植被长势的影响

气候变化是影响植被生长的重要因素,为了解干旱对植被生长的影响,本研究基于2022年7—9月川西高原气候条件、植被净初级生产力(Net Primary Productivity,NPP)指数、归一化植被指数(Normalized Difference Vegetation Index,NDVI)以及牧草产草量数据,分析了2022年7—8月干旱对川西高原植被长势的影响,并讨论了2000年以来气候因子与植被指数的关系。结果表明:NPP指数对干旱响应较为明显,2022年7月有62.50%区域的NPP指数低于历史同期,8月和9月NPP指数持续降低,9月高达80.83%区域的NPP指数低于历史同期;7—9月NDVI降低的区域面积分别占总面积的13.4%、36.2%和58.10%;牧草产量减少较为明显,与前两年相比,7—9月减产均在5%以上;气温和降水均对各项植被指数有不同程度的影响。