铝、镉对柱花草养分吸收的影响

以3个柱花草为供试材料,研究铝（Al）与镉（Cd）对柱花草生长及其对矿质营养元素吸收的影响,结果表明：在pH4.5条件下柱花草能正常生长,Cd处理对柱花草相对根长影响与Al处理无差异;西卡柱花草根及地上部Al和Cd的含量均显著低于热研2号和热研13号柱花草,热研2号和热研13号柱花草根系对Al和Cd的吸收无差异,但地上部Al和Cd的含量存在差异。铝镉处理不利于西卡柱花草根系对K、P、Mg、Mn的吸收;Cd降低热研2号及热研13号根系对K吸收,但有利于Fe的吸收;pH4.5处理或Al处理降低西卡柱花草和热研13号柱花草对Ca的吸收,说明酸化条件下或Al不利于柱花草根系从营养液中吸收Ca离子。Cd影响柱花草根系对Mg的吸收,但促进柱花草对Cu的吸收。     

应用体外产气法研究柱花草的饲用价值

以10个柱花草品种(品系)为试材,测定其营养成分及单宁含量,并结合体外产气法测定其体外干物质消化率和产气量。结果表明,饲料相对值RFV从大到小的排列顺序为:热研2号TPRC90028TPRC90089热研18号热研7号热研10号907CIAT11362热研5号热研13号;柱花草具有粗蛋白含量、代谢能含量较高,中性洗涤纤维、酸性洗涤纤维含量适中,单宁含量低,体外干物质消化率较高等特点,是一种优良的热带豆科牧草。     

热研7号柱花草的选育

进行了热研7号柱花草品种比较试验、区域试验和生产性试验的选育研究。研究结果表明:该品种具有高产、优质、抗病、耐寒、晚熟的特点。年平均干草产量14879.3kg·hm-2,年平均种子产量424.0kg·hm-2 ,分别比格拉姆柱花草增产84.0%、116.4%,与热研2号柱花草差异不显著。粗蛋白含量16.86%,粗脂肪含量2.65%,生育期为239d。可用于青饲料、干草粉生产等。适合我国热带、南亚热带地区种植。      

镉胁迫对3个品种圭亚那柱花草镉积累和矿质养分吸收的影响

利用不同浓度Cd2+溶液对3个品种圭亚那柱花草[Stylosanthes guianensis(Aublet)Swartz]进行不同程度的胁迫处理,以研究镉胁迫对柱花草生长、镉积累和矿质养分吸收的影响。结果表明:在镉胁迫下,3个品种圭亚那柱花草生长均受到抑制,TPRC2001-18(S.guianensis TPRC2001-18)受抑制作用最强,其次是热研10号(S.guianensis cv.Reyan No.10),而热研2号(S.guianensis cv.Reyan No.2)受抑制最弱。在镉胁迫下3个品种柱花草地上部和地下部镉含量均显著增加;镉浓度在1.0～5.0 mg/kg时,3个品种柱花草地上部镉含量从高到低的顺序为热研2号>热研10号>TPRC2001-18。镉胁迫能干扰柱花草对氮(N)、磷(P)、钾(K)养分的吸收。     

高产抗病圭亚那柱花草综合性状评价

1998年引进14个柱花草种质品种,以中国热带农业科学院选育的热研2号柱花草和热研5号柱花草为对照进行比较试验。结果表明:GC1480(IRRI)、GC1463(IRRI)和GC1517(IRRI)柱花草的干物质产量达11 377.5、9 360.2、9 296.7 kg/(hm2·a),分别比热研2号的高26.49％、4.06％和3.35％,比热研5号的高72.24％、41.70％和40.74％;且GC1480(IRRI)、GC1463(IRRI)柱花草的旱季干物质产量较高,具有较强的抗旱性;抗柱花草炭疽病能力优于热研5号柱花草;在定期刈割条件下,植株存活率分别达77.50％、50.00％和49.17％,具有较强的抗寒性;灰色关联分析评价结果表明,综合性状优于热研2号柱花草和热研5号柱花草。     

密度和施氮量对雅玉8号青贮玉米产量和品质的影响

研究不同种植密度和施氮水平对雅玉8号产量及品质的影响。结果表明,雅玉8号在四川资阳地区适宜种植密度为90 000株/hm2,最佳施氮量为200 kg/hm2,其地上干物质产量高达23 345 kg/hm2,果穗率为59.93%,粗蛋白含量为75.5 g/kg,粗纤维仅为124 g/kg,粗脂肪、粗灰分、无氮浸出物和钙含量分别为34.6、62.0、598和4.0 g/kg。种植密度和施氮水平对青贮玉米的地上干物质含量、粗蛋白产量及果穗率和粗纤维含量的影响均呈显著水平。     

南亚瓦鳞苔水提液对柱花草种子萌发及其幼苗生长的影响

为研究苔藓植物对柱花草幼苗生长的影响,选取苔藓植物中的苔类植物南亚瓦鳞苔(Trocholejeuneasandvicensis)为试材,以其配子体水提液分别对热研2号、热研5号和热研7号等3个柱花草品种进行处理,测定其发芽率、生长量、鲜重和干重。结果表明,在水提液浓度为2.5～7.5 g/L时可显著提高热研5号、热研7号柱花草种子萌发率;在浓度2.5～7.5 g/L时可显著提高热研2号种子发芽指数;在浓度为100 g/L时,可显著降低热研5号的鲜重,浓度为5.0 g/L时,可显著提高热研7号的幼苗干重。     

4份柱花草耐铝胁迫的差异

采用添加外源铝的水培和土培盆栽方法，研究了100 μmol/L Al3+对不同品种柱花草根系生长的影响。水培试验结果表明：短时间营养液培养24 h后，TPRC2001-1根尖和根系铝含量比其它3个柱花草低，西卡柱花草根尖和根系铝含量最高。柱花草的相对根长及根尖苏木精染色均反映出TPRC2001-1受抑制最小且根尖染色程度最浅，TPRC2001-1的细胞膜相对透性最低。土培盆栽试验结果表明：100 μmol/L Al（NO3）3长时间处理3个月后，TPRC2001-1地下部和地上部相对生物量均大于100％，而热研2号和西卡柱花草地下部和地上部相对生物量均低于50％。TPRC2001对铝的耐性最强，而西卡柱花草对铝敏感，热研2号和热研13号介于两者之间。     

热研2号柱花草和热研4号王草混合青贮对其营养成分及发酵品质的影响

为合理开发和利用热带牧草资源，研究热研2号柱花草和热研4号王草混合青贮对其营养成分及发酵品质的影响，以期筛选出适宜的混合青贮比例，为调制高品质的青贮饲料提供理论依据。本研究将热研4号王草和热研2号柱花草混合青贮比例分别设置为100∶0(CK)、85∶15(A1)、70∶30(A2)、55∶45(A3)4组，青贮30 d后开封取样检测。结果表明：A2组混合青贮感官评价最佳，随着热研2号柱花草比例的升高，pH和氨态氮/总氮（NH3-N/TN）值逐渐升高，A1、A2、A3组与CK组差异显著（P<0.05）；乳酸（LA）含量逐渐降低，A3组显著低于CK组（P<0.05）；各试验组乳酸/乙酸（LA/AA）值均大于2.6；且A2组丁酸（BA）显著低于其他各处理组（P<0.05）。随着热研2号柱花草比例升高，各处理组粗蛋白（CP）、干物质（DM）和粗脂肪（EE）含量随之升高，且显著高于CK组（P<0.05）；水溶性碳水化合物（WSC）含量呈上升趋势，且各试验组差异不显著（P>0.05）；中性洗涤纤维（NDF）逐渐降低，且各处理组间差异不显著（P>0.05）；各试验...     

热研2号柱花草高效固氮根瘤菌的筛选

为筛选与热研2号柱花草相匹配的高效固氮根瘤菌菌株，本研究进行了砂培试验，将22个根瘤菌菌株接种到热研2号柱花草根部，通过对柱花草茎叶干重、株高、氮和磷含量、有效根瘤数、固氮酶活性等指标的测定与分析，确定与柱花草匹配的高效菌株。结果表明：接种根瘤菌后，热研2号柱花草的茎叶干重和含氮量均高于不接种的植株，但菌株间的接种效果差异较大；接种菌株PN13-3、BS1-1、DH10-3、YM11-1、DH4-2和LZ3-2有利于产量和质量的提高，为热研2号柱花草的高效固氮匹配菌株；而接种菌株DF6、ZJ2-2、RJS9-2、NX1和RJS9-1对热研2号柱花草产量和质量的提高作用不大。     

湘南丘岗地区水稻轻简施肥技术的效应研究

通过田间小区试验,系统研究了在几种轻简施肥技术条件下双季早、晚稻的生育特性、养分吸收规律、肥料养分的当季利用率、经济性状和产量效应以及土壤速效养分的变化规律。结果表明：在轻简施肥技术条件下,双季稻前期早发不明显,中期成穗率高,后期根旺叶健不早衰;早、晚稻不同生育时期的干物质积累量与养分的吸收量具有相似性;早稻前期氮、磷、钾吸收量最低,绝大部分氮、磷、钾养分是在中、后期吸收的,晚稻前期的氮、磷、钾吸收量明显高于早稻,后期的氮、磷、钾吸收量大多低于早稻,不同处理之间差异不大。各轻简施肥处理均能提高早稻对氮和磷的表观利用率,以“湘珠专用肥”处理效果最好,但不能提高早稻对钾的表观利用率;晚稻轻简施肥处理“湘珠专用肥”也能明显提高水稻对肥料氮和钾的表观利用率。轻简施肥处理的水稻产量明显高于当地习惯施肥处理。     

杂交粳稻超高产群体干物质生产及养分吸收利用特点

 对超高产与高产杂交粳稻干物质生产及N、P、K养分积累、分配、利用进行了比较研究，结果表明，在干物质生产上，超高产杂交粳稻具有单丛干物重高、群体干物质生产量大，抽穗至成熟期的干物质积累量多、积累比例高，经济系数高的特点。在养分积累、分配与利用上，超高产条件下，稻株对N、P、K三要素的吸收量增加，特别是P、K的吸收量增加明显；成熟期在籽粒与茎中N、P、K的分配比例较高，而在叶片、叶鞘中的分配比例相对较低；同时，养分效率系数、养分收获指数及养分利用效率均高于高产条件下的效率参数，特别是以籽粒产量为计算基础的养分利用效率明显高于高产条件下的养分利用效率。     

淹水胁迫对不同土壤类型养分及玉米苗期养分吸收分配的影响

采用池栽试验,以潮土和砂姜黑土为对象,研究淹水胁迫下不同土壤类型速效养分变化及玉米苗期养分吸收分配的特征。结果表明,淹水胁迫导致两类土壤速效氮含量显著下降,随着淹水时间延长降低幅度增大;土壤速效磷含量呈倒抛物线型,在淹水3 d达最低值;速效钾含量呈上升趋势,潮土速效钾含量呈曲线上升趋势,砂姜黑土速效钾含量呈线性增加趋势。玉米养分及干物质的累积量和产量随着淹水时间延长而降低,氮、磷、钾的累积量分别降低21.37%~72.22%、22.00%~42.10%和11.71%~60.36%;干物质的累积量下降37.49%~57.17%;玉米产量下降9.05%~30.15%,砂姜黑土的下降幅度大于潮土。淹水减少了叶片和茎秆的养分及干物质累积量,增加了茎秆中的养分和干物质分配比例,平均增加25.95%和43.34%。     

不同施氮水平对金菠萝苗期生长及养分吸收的影响

氮素是影响植物生长和养分吸收的重要养分之一,为深入理解菠萝氮素营养生理,本研究以金菠萝为试验对象,通过盆栽试验研究不同施氮水平(0、25、50、100、150、300mg/kg)对金菠萝苗期植株生长、叶绿素和类胡萝卜素含量以及养分吸收的影响。结果表明:随施氮水平增加,金菠萝植株的叶片数、地上部干重、根系干重和总干重都持续增加,在300 mg/kg时生长最好;D叶中叶绿素a、b和类胡萝卜素含量随施氮水平升高呈先升后降的趋势,在100mg/kg时达到最大值;施氮水平增加提高了金菠萝植株N、P、K的吸收;随施氮水平升高,茎、叶中Ca、Mg、Mn、Cu、Zn含量上升,但茎、根中Fe含量下降,除Fe以外的中微量元素吸收量呈增加趋势。因此,本试验条件下,施氮水平增加促进了金菠萝苗期生长与养分吸收。     

Changes during growth in the nutritive value of components of berseem clover (Trifolium alexandrinum L.) under different cutting treatments in a Mediterranean region

The nutritive value of berseem clover (Trifolium alexandrinum L.) may be influenced by changes in the nutrient concentrations of morphological fractions as a consequence of cutting treatment. The aim of this study was to evaluate the effects of different cutting treatments on the nutritive value of herbage and leaf and stem components in two Mediterranean berseem genotypes during growth in order to develop management approaches for harvesting forage with a high nutritive value. Spring growth of genotypes of Egyptian (cv. Giza 10) and Italian (cv. Sacromonte) origins was harvested in each of 2 years beginning 196 days after sowing and thereafter every 6 days (twelve harvests in total) to measure dry matter (DM) yield and nutritive value. Cutting treatments were initiated at sixth internode elongation (A) and early flowering (B) and there was an uncut control treatment (C). In vitro digestibility of organic matter (IVOMD) and crude protein (CP) concentration were determined for leaf, stem and total forage of each cultivar at each harvest. For both cultivars, in the uncut treatment (C), DM yield increased linearly to a maximum of 14 800 kg ha^?1, on average, by 250 days after planting, the same time at which stem DM accumulation peaked, whereas the nutritive value, in terms of IVOMD and CP concentration, declined with age, coinciding with a reduction in leaf:stem ratio (LSR) from 1·00 to 0·30. Plant parts differed (P < 0·01) in nutritive value with stems being of lower nutritive value than leaves, in the two cutting treatments. There were strong positive correlations between LSR and herbage IVOMD and CP concentration, in both cutting treatments, indicating that, during growth, part of the changes in IVOMD and CP concentration of berseem clover plants was due primarily to the changes in the LSR. Defoliation induced a considerable reduction in DM yield, but an increase in the LSR and a small increase in nutritive value. Plants cut at the sixth internode elongation (A) showed a small proportional decrease (0·19) in total DM yield, but higher LSR values and similar or higher IVOMD and CP concentration than initiating cutting at early flower (B). Delaying defoliation to the early flowering stage (B) increased the proportion of stems and, therefore, decreased nutritive value. Therefore, harvest management in which cuts are applied at the stage of sixth internode elongation appears to be the most favourable for obtaining relatively high yields of forage with high nutritive value in berseem clover grown in Mediterranean regions.     

THE EFFECT OF NITROGEN FERTILIZER AND CLIPPING FREQUENCY UPON THE YIELD AND IN VITRO DIGESTIBILITY OF INTERMEDIATE WHEATGRASS

The effect of rate of nitrogen fertilizer and clipping frequency on total production of dry matter (DM), in vitro digestible organic matter (DOM), and crude protein (CP) was investigated in the first harvest year of intermediate wheatgrass. The highest yields of DM and DOM, but not of CP, were obtained at the longest clipping intervals and at the higher rates of fertilizer application. Fertilizer failed to give satisfactory increases in yield even at very high rates of application when a 2-week clipping interval was used. The interaction between clipping frequency and fertilizer rate had a highly significant effect on yields of both DM and DOM. A sharp decline in percentage DOM that occurred with increasing length between clippings was offset to some degree by application of N fertilizer. A similar assessment of treatments was obtained from DOM and DM yield data when the grass was fertilized with N, but not when N was deficient. The CP data gave a different assessment of treatments from that obtained from either DOM or DM data.     

Estimating maize nutrient uptake requirements

Generic, robust models are needed for estimating crop nutrient uptake requirements. We quantified and modeled grain yield–nutrient uptake relations in maize grown without significant biotic and abiotic stresses. Grain yield and plant nutrient accumulation in above-ground plant dry matter (DM) of commercial maize hybrids were measured at physiological maturity in on-station and on-farm experiments in Nebraska (USA), Indonesia, and Vietnam during 1997–2006. These data were used to model the nutrient requirements for yields up to 20 Mg ha⁻¹ using the QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) approach. The model required estimation of two boundary lines describing the minimum and maximum internal nutrient efficiencies of N, P and K (IE, kg grain per kg nutrient in plant DM), which were estimated at 40 and 83 kg grain kg⁻¹ N, 225 and 726 kg grain kg⁻¹ P and 29 and 125 kg grain kg⁻¹ K, respectively. The model predicted a linear increase in grain yield if nutrients are taken up in balanced amounts of 16.4 kg N, 2.3 kg P and 15.9 kg K per 1000 kg of grain until yield reached about 60–70% of the yield potential. The corresponding IEs were 61 kg grain kg⁻¹ N, 427 kg grain kg⁻¹ P and 63 kg grain kg⁻¹ K. The model predicted a decrease in IEs when yield targets approached the yield potential limit. A spherical model was derived from QUEFTS model outputs and found to be particularly suitable for practical applications such as estimating fertilizer needs. The proposed spherical model offers generality across environments and management practices, allowing users to estimate the optimal N, P and K uptake requirements based on two inputs: estimated yield potential and yield target. Further improvements in modeling the relationship between N uptake and grain yield can be made by taking into account differences in harvest index. Accuracy in the simulation of N uptake using the spherical model was improved from an RMSE of 35 kg N ha⁻¹ to 25 kg N ha⁻¹ when harvest index was accounted for, suggesting that the relationship between N uptake and actual yield is affected by both yield potential and efficiency in biomass partitioning.     

水稻-再生稻体系干物质积累及氮磷钾养分的吸收利用

【目的】 阐明水稻-再生稻体系的干物质积累及氮、磷、钾养分吸收利用规律,为其科学施肥提供理论依据。【方法】 通过2年的田间试验,以深两优5814为材料,在养分供应充足的条件下,于水稻关键生育期(分蘖期、幼穗分化期、孕穗期、齐穗期、灌浆期、完熟期)进行取样,测定各器官的干物质量及氮、磷、钾养分含量,计算养分积累量,研究头季稻和再生稻干物质积累和氮、磷、钾养分吸收积累动态及分配、转运规律。【结果】 头季稻总干物质积累量在整个生育期表现为“慢-快-慢”的增长趋势,茎、叶干物质快速积累期分别在分蘖-齐穗期和孕穗前,增长量分别占其最大积累量的81.1%和43.8%,且茎、叶的干物质积累量在灌浆-完熟期之间没有明显降低;从齐穗期至灌浆中期是穗的干物质快速积累期,在此期间增加的干物质积累量占总量的58.8%。再生稻的总干物质积累呈“S”形曲线,茎、叶的干物质积累量分别在灌浆期和齐穗期达到最大;头季稻桩的干物质积累量从头季收割后呈下降趋势。养分吸收结果显示,头季稻氮的总积累量以及茎、穗两个器官的氮素积累量的变化规律与其干物质积累量相似,磷和钾的总积累量在灌浆后期降低;茎和叶的各养分积累量分别在齐穗期和灌浆期达到最大。头季收获后,头季稻桩的氮、磷和钾养分积累量表现为下降的趋势,茎和叶的养分积累量先增加后减少,穗的养分积累量则表现为不断增加。从齐穗期到完熟期,各器官的氮转运量表现为叶>茎>头季稻桩,磷转运量表现为茎>头季稻桩>叶,钾转运量表现为头季稻桩>叶>茎。【结论】 头季稻孕穗期至灌浆中期是其干物质和养分的快速积累期,从头季收获至再生季齐穗期间是再生稻干物质及养分积累的关键时期,头季稻桩中的养分会在头季收获后转移至再生器官中。满足头季稻抽穗灌浆期间的养分需求,及时补充再生芽萌发生长期间的养分供应是水稻-再生稻体系高产的基础和保障。     

热研8号坚尼草选育及利用研究

热研8号坚尼草是1988年从哥伦比亚国际热带农业中心(CIAT)引进的新品系,经鉴定于1990年开始进行系列研究。研究结果表明,热研8号坚尼草既保持了该属牧草高产优质的特点,年干草产量22500kg/hm2,干物质粗蛋白质含量7.738%,又具有耐酸、耐瘦、耐荫等特点;花期晚,利用期比对照品种增加1个月,种子产量480kg/hm2,比对照品种提高87.8%,适宜我国热带及亚热带地区种植。      

不同肥料滴灌配施夏玉米产量与氮磷钾吸收利用特性

以郑单958为材料,在滴灌施肥条件下设不施氮(N0)、不施磷(P0)、不施钾(K0)和氮磷钾均施(NPK)4个处理,以传统灌溉施肥方式(施用量同NPK处理)为对照,研究滴灌水肥一体不同肥料配施夏玉米产量与氮磷钾吸收、分配及利用特性。结果表明,滴灌条件下,相较于磷钾肥,玉米对氮肥更敏感。N0处理的产量、干物质积累量、整株氮磷吸收量均显著降低,其叶片钾含量、茎鞘磷含量极显著增加,导致叶片钾积累量、茎鞘磷积累量显著增加。P0和K0处理玉米产量、干物质积累量、植株氮素吸收量均与NPK处理无显著差异,分别导致磷素和钾素吸收量显著降低。不施磷钾肥处理氮素从秸秆向子粒的转运受到限制,子粒含氮量下降,氮素收获指数显著降低。滴灌条件下,氮磷钾肥平衡施用玉米养分吸收均衡、分配合理,物质生产和产量显著高于传统灌溉施肥方式。