Steel Slag as an Iron Fertilizer for Corn Growth and Soil Improvement in a Pot Experiment

The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that moderate rates (10 and 20 g kg-1) of slag or acidified slag substantially increased corn dry matter yield and Fe uptake. Application of steel slag increased the residual concentration of ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA) extractable Fe in the soils. The increase of extractable Fe was usually proportional to the application rate, and enhanced by the acidification of slag. Steel slag appeared to be a promising and inexpensive source of Fe to alleviate crop Fe chlorosis in Fe-deficient calcareous soils.

Application of Mulching Materials of Rainfall Harvesting System for Improving Soil Water and Corn Growth in Northwest of China

The ridge and furrow rainfall harvesting（RFRH） system is used for dryland crop production in northwest of China.To determine the effects of RFRH using different mulching materials on corn growth and water use efficiency（WUE）,a field experiment was conducted during 2008-2010 at the Heyang Dryland Experimental Station,China.Four treatments were used in the study.Furrows received uncovered mulching in all RFRH treatments whereas ridges were mulched with plastic film（PF）,biodegradable film（BF） or liquid film（LF）.A conventional flat field without mulching was used as the control（CK）.The results indicated that the average soil water storage at depths of 0-200 cm were 8.2 and 7.3%,respectively higher with PF and BF than with CK.However,LF improved soil water storage during the early growth stage of the crop.Compared with CK,the corn yields with PF and BF were increased by 20.4 and 19.4%,respectively,and WUE with each treatment increased by 23.3 and 21.7%,respectively.There were no significant differences in corn yield or WUE with the PF and BF treatments.The net income was the highest with PF,followed by BF,and the 3-yr average net incomes with these treatments were increased by 2 559 and 2 430 CNY ha-1,respectively,compared with CK.BF and PF had similar effects in enhancing the soil water content,crop yield and net income.Therefore,it can be concluded that biodegradable film may be a sustainable ecological alternative to plastic film for use in the RFRH system in northwest of China.

Corn Growth as Affected by Plastic Cover Under Drip Irrigation Condition in the Desert

Plastic cover as a method to minimize soil water evaporation and improve water use efficiency, was used for corn during the whole growing period in a desert area. Field studies were conducted to determine the effect of plastic covering management on corn growth and rooting pattern and its relationship with changes in climate. Four treatments, 0) bared soil without cover) 1) covering one side of the crop, 2) covering both sides of the crop, and 3) covering the surface totally, were established on a sandy loam soil. Results showed that treatment 0 was significantly different from others and revealed that plastic covering was not always good to corn growth. Improper usage of plastic cover might weaken root development and thereafter lower the total yield of the crop. Suitable practices combining different methods discussed could not only improve water use efficiency but also increase the crop yield.

Effect of Plant Growth-Promoting Rhizobacteria at Various Nitrogen Rates on Corn Growth

Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and promote plant growth by producing and secreting various chemical regulators in the rhizosphere. With the recent interest in sustainable agriculture, an increasing number of researchers are investigating ways to improve the efficiency of PGPR use to reduce chemical fertilizer inputs needed for crop production. Accordingly, greenhouse studies were conducted to evaluate the impact of PGPR inoculants on biomass production and nitrogen (N) content of corn (Zea mays L.) under different N levels. Treatments included three PGPR inoculants (two mixtures of PGPR strains and one control without PGPR) and five N application levels (0%, 25%, 50%, 75%, and 100% of the recommended N rate of 135 kg N ha−1). Results showed that inoculation of PGPR significantly increased plant height, stem diameter, leaf area, and root morphology of corn compared to no PGPR application under the same N levels at the V6 growth stage, but few differences were observed at the V4 stage. PGPR with 50% of the full N rate produced corn biomass and N concentrations equivalent to or greater than that of the full N rate without inoculants at the VT stage. In conclusion, mixtures of PGPR can potentially reduce inorganic N fertilization without affecting corn plant growth parameters. Future research is needed under field conditions to determine if these PGPR inoculants can be integrated as a bio-fertilizer in crop production nutrient management strategies.

Association of host plant growth and weed occurrence with armyworm(Mythimna separata) damage in corn fields

To clarify association between armyworm（Mythimna separata） damage level and the corn growth and weed occurrence, we investigated corn plant height, stem diameter and vigor as well as weed coverage and biomass. The investigations were conducted at three locations of Shaanxi Province, China which were suffered seriously from armyworm. Significant correlations were found between the parameters analyzed. At stunted corn growth and presence of plenty of weeds, the armyworm damage tended to be heavy; oppositely, when corn grew well and weed density were low, armyworm harm was the minimal. Therefore, corn growing status and weed density can significantly affect armyworm damage level. Our results imply that promoting corn growth and timely removal of weeds are conducive to reducing armyworm occurrence.

Moderate sewage sludge biochar application on alkaline soil for corn growth:a field study

In view of the risks induced by the inhibitory effects of applying impracticably large amounts of sewage sludge biochar(SSB)to the alkaline soil,this field study investigated the influence of moderate biochar amendments(0,1500,4500,and 9000 kg/hm2)on corn growth,alkaline soil properties,and the uptake of potentially toxic elements(PTEs).The results showed that applying more SSB would decrease the ammonium nitrogen concentration and increase the available phosphorus and potassium concentrations,which inhibited corn plant growth because of high background nutrient levels of the alkaline soil.When the alkaline soil was amended with 1500 kg/hm2 SSB,the dry weight of 100 niblets increased from 32.11 g in the control to 35.07 g.There was no significant variation in the total concentration of PTEs in the soil.The concentrations of Mn,Ni,Cu,and Zn in niblets decreased from 5.54,0.83,2.26,and 27.15 mg/kg in the control to 4.47,0.62,1.30,and 23.45 mg/kg,respectively.Accordingly,the health risk from corn consumption was significantly reduced.Furthermore,the combination of SSB and fertilizer improved corn growth and reduced the risk of consumption of PTEs.Therefore,considering the increase in corn fruit yield and the decrease in consumption risk,applying 1500 kg/hm2 of biochar to alkaline soils is a realistically achievable rate,which can broaden the utilization of SSB for remediation of different types of soil.

The Effect of Dietary Supplementation with Phytase Transgenic Corn on Growth Performance,Phosphorus Utilization and Excretion in Growing Pigs (Sus scrofa)

Two experiments were conducted to investigate the effect of dietary supplementation with phytase transgenic corn （PTC） on growth performance,phosphorus （P） utilization and excretion in growing pigs.In Exp.1,180 pigs （Large White × Landrace,BW=37.7 kg） were randomly allotted to 4 treatments with 5 replicates of 9 pigs each in order to evaluate the effect of PTC supplementation in low-P diets on growth performance.Four corn soybean meal-based diets consisted of a positive control （PC） diet,a diet containing 500 units （U） of exogenous phytase kg-1 （EP） on the basis of low-P （inorganic P reduced by 0.05% from PC diet） and the low-P＋500 （PTC1） or 750 （PTC2） phytase U of PTC kg-1.In Exp.2,20 barrows （Large White×Landrace,BW=31 kg,4 treatments with 5 replicates of 1 pig each） were randomly selected to evaluate the effect of PTC in low-P diets on serum parameters and nutrient utilization.Diets in Exp.2 were similar to those in Exp.1 except that the EP group was replaced by a low-P diet without exogenous phytase supplementation as a negative control （NC） group.The results from Exp.1 showed that the average daily gain （ADG） in the PTC2 group was significantly higher （P〈0.05） than that in the EP group over all periods.On the other hand,the feed：gain （F：G） ratio of the EP group was significantly higher （P〈0.05） than that of the PTC2 group during 1-21 and 1-42 d,respectively.There were no differences in average daily feed intake （ADFI） among all treatments （P〉0.05）.The results from Exp.2 showed that the concentration of serum Ca in the NC group was the highest （P〈0.05）,while the concentration of serum P in the PTC2 group was the highest （P〈0.05） among all treatments.There was a significant decrease （P〈0.05） in the P apparent digestibility of the NC group compared with the other groups,and that of PTC2 group was the best.Furthermore,fecal P excretion was reduced （P〈0.05） from 1.80 g d-1 in the PC group to 1.28 g d-1 in the PTC2 group.In conclusion,dietary supplementation with PTC could reduce the application of inorganic P,decrease fecal P excretion,and improve the growth performance of growing pigs.

Effect of Ammonium Polyphosphate on Plant Growth Development and Absorption of Phosphorus and Zinc in Corn Seedlings

Using pot experiment to study the effect of new fertilizer ammonium polyphosphate on plant growth and uptake of phosphorus and zinc in corn seedlings. The results showed that under the conditions of equal phosphate fertilizer application, ammonium polyphosphate added to phosphate fertilizer could significantly improve the plant height and stem diameter of corn seedlings after sowed for 60 days, while improved biomass of corn overground part and roots and root shoot ratio. When the ratio of ammonium polyphosphate and diammonium phosphate was 2：1 （available phosphorus ratio）, the effect was the best. Ammonium polyphosphate had little effect on the phosphorus content of overground part of corn seedlings, but increased the phosphorus cumulant. In addition, ammonium polyphosphate applica- tion significantly improved the zinc concentration and zinc cumulant of corn over- ground part and roots. The results showed that ammonium polyphosphate had bet- ter bioavailability, meanwhile promoted the absorption of microelement zinc in crops.

Changes in Climatic Factors Influencing the Growth Period of Corn in Fengjie County

Under the background of global climate change,we analyze the change tendency of average temperature and amount of precipitation influencing the corn's growth period. The results show that from March to August,the monthly temperatures show an upward trend,but the rise is different in different months,and the maximum temperature rise is in May. Precipitation in different months has different trends. Climate change brings about favorable conditions at high altitudes in Fengjie,reduces production due to the temperature drop after the beginning of autumn,and increases the pressure on the corn supply.

Evaluation of Impact of Pollen Grains from Bt,Bt/CpTITransgenic Cotton and Bt Corn Plants on the Growth andDevelopment of the Mulberry Silkworm,Bombyx moriLinnaeus (Lepidoptera:Bombycidae)

The S-endotoxin genes of Bacillus thuringiensis (Bt) and proteinase inhibitor (PI) genes are two kinds of genes popularly used for developing transgenic plants resistant to insect pests. To clarify whether there is any risk concerning the effects of pollens from these transgenic crops on non-target insects with economic importance, such as the effects on the growth and development as well as cocoon quality of the silkworm, Bombyx mori Linnaeus, a series of feeding experiments were conducted, using pollens from transgenic cotton or corn containing cry 1Ac, cry1A+CpTI or crylAb genes, compared with pollens from non-transgenic normal cotton and corn as well as the non-pollen treatment. In contrast to the latter ones, pollens from transgenic plants showed no significant adverse effects on larval mortality, cocoon weight, pupa weight, cocoon shell weight, pupation rate, emergence rate and fecundity of the silkworm after neonates were fed with the pollens for 72 h. In addition, no dosage effects of pollens were found. Though the duration of 1st instar larvae was prolonged in the case of feeding with transgenic pollens as compared with those of the non-pollen treatment , but they were not significantly different from those fed with pollens from non-transgenic cotton or corn. Meanwhile, the body weight of the 3rd instar molters fed with transgenic pollens was obviously different from those for non-pollen treatment, and was all significantly heavier than that of the controls. Consequently, it is considered that the adverse effect of pollens from transgenic insect-resistant cotton and corn on the growth and development of the silkworm is negligible.

Corn Yield Response to Reduced Water Use at Different Growth Stages

To develop an efficient water use strategy for crop irrigation, we need to know how much water can be reduced without decreasing yield. A study was designed to determine corn growth stages at which water could be reduced without affecting grain yield, and at what soil moisture level water deficit stress begins in the plants in a silt loam soil. An experiment was conducted in a randomized complete block with a 3 × 4 factorial design in four replications, where treatments consisted of three soil moisture levels [100%, 75%, and 50% of field capacity (FC) of a silt loam soil by weight] and four growth stages [fourteen leaf stage (V14), silking (R1), milk (R3), and dent (R5) stages] in a greenhouse. Growth stages at the reproductive and grain fill stages of corn were selected because this study was intended for the Mississippi Delta, where there is frequent drought during these growth stages making irrigation necessary for corn production, whereas there is usually adequate rainfall during the vegetative growth stages. Results from this study showed that reducing soil moisture from 100% FC (fully irrigated) to 75% FC of a silt loam soil starting at the R1 growth stage in corn did not reduce yield significantly compared to yield from the 100% FC, while saving a significant amount of water. Physiological investigations at the three soil moisture treatments showed that a mild moisture deficit stress might have started at the 75% FC treatment. With further investigation, if savings in water at 75% FC result in a significant reduction in energy cost, it may be profitable to reduce soil moisture to 75% FC in a silt loam soil.

全株玉米青贮不同比例替代花生秧对肉羊生产性能及肉品质的影响

试验旨在研究全株玉米青贮不同比例替代花生秧对肉羊生长性能、屠宰性能、肉品质和营养物质消化率的影响。选取杜寒杂交育肥羊100只,随机分为4组,每组5个重复,每个重复5只羊。对照组饲喂含100%花生秧的基础饲粮,3个试验组分别饲喂利用全株玉米青贮替代50%(50%替代组)、75%(75%替代组)、100%(100%替代组)花生秧的试验饲粮,试验期30 d。结果表明:与对照组相比,75%替代组可以显著提高肉羊试验期末重和平均日增重(P<0.05),显著降低肉羊试验期料重比(P<0.05),且75%替代组肉羊试验期末重和平均日增重显著高于50%替代组和100%替代组(P<0.05),料重比显著低于100%替代组(P<0.05);75%替代组可以提高肉羊屠宰前活体重(P<0.05)、胴体重(P>0.05)和眼肌面积(P>0.05);3个替代组对肉羊肉品质各项指标均无显著影响(P>0.05);75%替代组可以显著提高肉羊干物质和有机物的表观消化率(P<0.05)。综上所述,肉羊养殖饲粮中应用全株玉米青贮替代75%的花生秧可以提高肉羊生长性能、屠宰性能及饲粮中干物质和有机物的表观消化率。

保水剂和蒸腾抑制剂对玉米生长和水肥耦合的影响

保水剂和蒸腾抑制剂的应用对玉米高效生产发挥着重要作用。为探究保水剂和蒸腾抑制剂对玉米生长和土壤水肥耦合的影响,在内蒙古自治区鄂尔多斯市乌审旗河南乡小石砭村进行田间试验。试验共设置4个处理,分别为灌水定额为30 mm并且施加保水剂(C1)、灌水定额为37.5 mm并且施加保水剂(C2)、灌水定额为45 mm并且施加蒸腾抑制剂(C3)和灌水定额为45 mm并且不施加试剂(CK)。结果表明:①保水剂和蒸腾抑制剂能有效提升土壤保水能力,与CK相比,C1、C2和C3处理下玉米生育期平均土壤含水率分别提升6.61%、11.94%和4.05%。②保水剂和蒸腾抑制剂能有效提升玉米株高,其中拔节期玉米株高提升率最高,C1、C2和C3较CK分别提升9.40%、17.45%和6.04%。③玉米的茎粗随着生育期的推进呈现出先快速增长后缓慢增长再略微减小的趋势,快速增长期为拔节期,拔节期相比于苗期茎粗平均增长率为60.21%。④保水剂的施加可以增加土壤肥力和土壤水肥之间的协同关系,C2相比于CK土壤全氮、有效磷、速效钾、缓效钾和有机质含量分别增加37.57%、82.76%、88.66%、1.31%和37.83%;土壤水肥耦合度和耦合协调度分别增加77.74%和52.79%。综上所述,施加保水剂和蒸腾抑制剂可有效改善土壤水分状况,促进玉米生长发育,较不施加任何试剂的处理有明显优势。

玉米蛋白粉替代豆粕对肉牛生长性能、氮代谢及屠宰性能的影响

文章旨在研究玉米蛋白粉(Corn Gluten Meal,CGM)替代豆粕对肉牛生长性能、氮代谢及屠宰性能的影响。试验将96头健康、370 kg左右的西门塔尔肉牛随机分为4组,每组3个重复,每个重复8头。CON组根据肉牛饲养标准(NY/T 815-2004)配制全混合日粮,其余3组在全混合日粮中分别添加2.5%(CGML组)、5.0%(CGMM组)、7.5%(CGMH组)的玉米蛋白粉(等氮替代豆粕),试验为期80 d。结果表明:(1)与CON组相比,CGMH组肉牛的末重、平均日增重显著降低(P<0.05),料重比显著提高(P<0.05)。4组中CGML组肉牛的末重、平均日增重最高,料重比最低。(2)与CON组相比,CGMM组、CGMH组肉牛的沉积氮、氮利用率显著降低(P<0.05),CGML组肉牛的沉积氮、氮利用率高于CON组,但无显著差异(P>0.05)。(3)与CON组相比,CGMH组肉牛的宰前活重、胴体重、净肉重均显著降低(P<0.05)。4组中CGML组肉牛的宰前活重、胴体重、净肉重最高。结论:综合各项指标,在不考虑饲料成本的情况下,肉牛全混合日粮中玉米蛋白粉的适宜添加水平为2.5%。

蒸汽压片玉米对肉牛生长性能、屠宰性能和肉品质的影响

为了研究蒸汽压片玉米对肉牛生长性能、屠宰性能和肉品质的影响,试验拟选用40头体重(224.05±14.56)kg的西门塔尔杂交肉牛,随机分为4组,每组5个重复,每个重复2头肉牛。对照组饲粮中添加粉碎玉米,试验Ⅰ组~Ⅲ组分别用33%、66%、100%的蒸汽压片玉米替代粉碎玉米。预试期7 d,正式试验期120 d。结果显示,试验Ⅱ组和试验Ⅲ组末重比对照组分别提高了6.27%(P<0.05)和10.64%(P<0.01),试验Ⅰ组~Ⅲ组总增重比对照组分别提高了7.56%(P<0.05)、21.29%(P<0.01)和33.45%(P<0.01),试验Ⅰ组~Ⅲ组宰前活重比对照组分别提高了2.64%(P<0.05)、6.59%(P<0.01)和10.25%(P<0.01),试验Ⅱ组和Ⅲ组料重比极显著低于对照组(P<0.01)。试验Ⅱ组和Ⅲ组胴体重、净肉重均极显著高于对照组(P<0.01)。试验Ⅱ组和Ⅲ组牛肉中粗蛋白的含量极显著高于对照组(P<0.01),试验Ⅲ组粗脂肪显著高于对照组(P<0.05),试验Ⅲ组的pH_(45 min)值和失水率显著低于对照组(P<0.05)。试验Ⅰ组~Ⅲ组养殖效益比对照组分别提高了15.36%、48.04%和77.98%。研究表明,用蒸汽压片玉米替代肉牛饲粮中普通粉碎玉米可以提高西门塔尔杂交肉牛的生长性能和屠宰性能,改善牛肉品质,提高了肉牛养殖的经济效益,在饲粮中使用100%的蒸气压片玉米替代普通粉碎玉米效果较好。

玉米秸秆穰叶对肉羊生长性能、养分表观消化率、血清生化指标及免疫指标的影响

试验旨在研究玉米秸秆穰叶对肉羊生长性能、养分表观消化率及血清生化指标的影响。选取健康状况较好、体重(30.0±3.0)kg的母羊30只,按体重相近原则,随机分为2组,每组3个重复,每个重复5只羊。对照组以整株玉米秸秆作为粗饲料,试验组以玉米秸秆穰叶作为粗饲料,试验组和对照组精料一致。预试期10 d,正式试验期90 d。结果显示,与对照组相比,试验组肉羊的平均日增重提高了10.58%,平均日干物质采食量提高了1.01%,料重比降低了8.66%。试验组肉羊对饲粮中干物质、粗蛋白、粗脂肪、中性洗涤纤维、酸性洗涤纤维、钙及磷的表观消化率分别比对照组提高了6.52%、8.69%、9.43%、8.17%、8.43%、5.87%和6.51%。试验组肉羊血清中总蛋白含量、球蛋白含量及碱性磷酸酶活性分别比对照组提高了3.41%、10.70%和12.42%,尿素氮含量降低了5.00%。试验组肉羊血清中免疫球蛋白A、免疫球蛋白M、免疫球蛋白G、补体C3和补体C分别比对照组提高了5.89%、7.90%、7.58%、6.95%和2.66%。研究表明,与整株玉米秸秆相比,玉米秸秆穰叶是草食家畜的一种优质粗饲料。

不同种植密度对青贮玉米生长、产量及经济效益的影响

文章旨在研究不同种植密度对青贮玉米生长、产量及经济效益的影响,为青贮玉米推广种植提供数据参考。青贮玉米品种选择适宜甘肃本地种植的陇青贮2号,在相同水肥管理条件下,分别设置低(6.75×10^(4)株/hm^(2))、中(7.50×10^(4)株/hm^(2))、高(8.25×10^(4)株/hm^(2))3个种植密度组,以小区测样方式,统计青贮玉米(乳熟后期至蜡熟前期)的生长、产量及经济效益情况。结果表明:(1)随着种植密度的提高,青贮玉米平均株高和平均叶片数呈下降趋势(P<0.10),与低种植密度组(6.75×10^(4)株/hm^(2))相比,高种植密度组(8.25×10^(4)株/hm^(2))青贮玉米平均穗位高和倒伏率显著提高3.00%、57.06%(P<0.05),平均茎粗显著降低12.19%(P<0.05)。(2)不同种植密度对青贮玉米产量各项指标均无显著差异(P>0.05)。(3)在经济效益方面,低、中、高种植密度组青贮玉米毛利分别为51898.77、56723.45、56497.11元/hm^(2)。结论:综合对比各项指标,陇青贮2号青贮玉米适宜种植密度为7.50×10^(4)株/hm^(2)。

青贮果穗玉米对生长育肥猪生长性能和猪肉品质的影响

为研究饲粮中添加青贮果穗玉米对生长育肥猪生长性能、胴体性状及肌肉品质的影响,本试验以192头日龄相近,初始体重为(36.82±1.50) kg的“杜×长×大”商品猪为研究对象,随机分为对照组和试验组(Ⅰ、Ⅱ、Ⅲ),每组4个重复。对照组饲喂基础饲粮,试验组在生长阶段(54 d)分别饲喂含15%、30%和45%青贮果穗玉米的试验饲粮,育肥阶段(62 d)分别饲喂含23%、46%和69%青贮果穗玉米的试验饲粮。结果表明,青贮果穗玉米饲粮对生长育肥猪胴体性状和肌肉品质各项指标无显著影响。对照、试验Ⅲ组全期平均日增重显著低于试验Ⅰ组(P<0.05),其他生长性能指标无显著影响。试验Ⅲ组肌肉亚油酸含量较对照组显著增加36.22%(P<0.05),粗脂肪含量较对照组和试验Ⅰ组显著降低(P<0.05)。综上可知,猪生长、育肥阶段饲粮适宜的青贮果穗玉米含量比例分别为15%~30%和23%~46%,可为其在生长育肥猪上的推广应用提供数据支撑。

发酵玉米芯对肉牛生长性能、瘤胃发酵参数及菌群的影响

本试验旨在研究发酵玉米芯对肉牛生长性能、瘤胃发酵参数及菌群的影响。选用60头体况良好、13月龄左右、体重[(395±32)kg]相近的西门塔尔杂交牛,随机分为3组,每组20个重复,每个重复1头牛。对照组饲喂不添加发酵玉米芯的全混合日粮,试验1组饲喂添加10%发酵玉米芯的全混合日粮,试验2组饲喂添加20%发酵玉米芯的全混合日粮,预试期7 d,正试期93 d。结果显示:1)试验1、2组的平均日采食量和平均日增重显著高于对照组(P<0.05),料重比显著低于对照组(P<0.05)。2)试验1、2组瘤胃液氨态氮(NH_(3)-N)浓度与对照组相比均显著升高(P<0.05),试验2组瘤胃液微生物蛋白(MCP)浓度与对照组和试验1组相比显著提高(P<0.05);各组瘤胃液pH无显著差异(P>0.05);2个试验组瘤胃液总挥发性脂肪酸(TVFA)浓度均显著低于对照组(P<0.05),但乙酸、丙酸、戊酸摩尔百分比及乙酸/丙酸值没有显著变化(P>0.05);2个试验组瘤胃液丁酸摩尔百分比显著低于对照组(P<0.05),而异丁酸和异戊酸摩尔百分比均显著高于对照组(P<0.05)。3)门水平上,拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes)为3组肉牛瘤胃菌群中的主要优势菌门。试验1、2组Bacteroidetes的相对丰度显著高于对照组(P<0.05),试验2组Firmicutes的相对丰度显著低于对照组(P<0.05)。属水平上,3组的主要优势菌属均为普雷沃氏菌属(Prevotella)、拟杆菌目未鉴定属(unidentified Bacteroidales)。试验1、2组普雷沃氏菌科未鉴定属(unidentified Prevotellaceae)的相对丰度显著高于对照组(P<0.05),同时试验1组还显著高于试验2组(P<0.05);对照组Ruminococcus和甲烷短杆菌属(Methanobrevibacter)的相对丰度显著高于试验1、2组(P<0.05);试验2组的梭菌目未分类属(unclassified Clostridiales)和毛螺菌科未鉴定属(unidentified Lachnospiraceae)的相对丰度显著低于对照组和试验1组(P<0.05)。综上所述,饲粮中添加发酵玉米芯能够提高肉牛的生长性能,改善瘤胃发酵环境,同时影响瘤胃菌群在门水平和属水平上的组成。

干旱胁迫下两种芽胞杆菌对玉米幼苗促生作用研究

供试玉米品种为‘先玉335’(XY335),供试菌株为NECC11322(Bacillus subtilis)枯草芽胞杆菌、NECC11324(B.megaterium)巨大芽胞杆菌。试验设4组处理:Con(无菌水浸种,干旱胁迫),C1(无菌水浸种,正常供水),C2(NECC11322菌液浸种,干旱胁迫),C3(NECC11324菌液浸种,干旱胁迫),测定了浸种后盆栽玉米幼苗的生长状况、抗性生理指标及植株的N、P、K含量。结果表明:在干旱胁迫下接种NECC11322、NECC11324后,玉米幼苗叶片及根系SOD、POD、CAT、APX活性较Con均不同程度升高,其中接种NECC11322根系POD活性增长最为显著,较Con增长67.78%;植株叶片及根系可溶性蛋白含量、可溶性糖含量较Con均呈上升趋势,其中接种NECC11322叶片可溶性糖含量增长最为显著,较Con增长152.10%;与Con相比,植株叶片及根系全氮、全磷、全钾养分含量均有所提升,接种NECC11322后叶片全氮含量升高最为显著,较Con增长88.47%;干旱胁迫下接种两种芽胞杆菌后,植株叶片及根系丙二醛含量较Con均显著降低,接种NECC11322后根系降幅最为显著,较Con降低51.03%。综上可知,干旱胁迫下接种两种芽胞杆菌均可降低干旱胁迫对玉米幼苗生长的抑制,其中NECC11322菌株更具有抗旱性。通过提高保护酶活性、可溶性蛋白、可溶性糖含量、叶绿素含量以及植株养分含量提高玉米幼苗抗旱性,促进玉米幼苗生长。