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排序方式: 共有9667条查询结果,搜索用时 15 毫秒
1.
In this study, the effects of nitrogen (N) rate (60, 120, 180 and 240 kg N ha?1 applied in three equal dressings at seeding and after the first and second cuttings) and stubble height (7, 14 and 21 cm) on the dry matter (DM) yield, crude protein (CP) content, and CP yield of a sorghum–sudangrass hybrid [Sorghum bicolor (L.) Moench × Sorghum sudanense (Piper) Stapf., cv. Pioneer 988] in the three‐cut system was investigated. The N rate had no significant effect in the first and third cuttings, but in the second cutting DM yields increased significantly with increase in N rate. The highest yield of 9.1 t ha?1 was obtained with 80 kg N ha?1 for the average of 2 years at the second cutting, but no significant difference was found among the 40, 60 and 80 kg N ha?1 rates. CP content and yield were not significantly affected by N rate at the first and third cuttings, but CP content and yield were significantly affected by application of N at the second cutting. Stubble height had a significant effect on CP content at the third cutting. However, it had no significant effect on CP content at the first and second cuttings. Stubble height had a significant effect on the CP yield at the first cutting, but no significant effect on CP yield at the second and third cuttings. 相似文献
2.
国产硝酸磷肥含氮27%,磷13.5%。所含速效氮中硝态氮均占一半。研究麦田不同水分对硝酸磷肥中硝态氮在土壤中扩散结果显示,硝态氮在土壤中下移深度与土壤湿润峰的深度基本一致,在小麦越冬期有表聚现象。当灌水量为田间持水量时,硝态氮移动深度为40~50cm,是在主要根系活动层内,这对小麦吸收有利,不会产生氮的流失。等氮磷条件下,硝酸磷肥与磷铵加尿素在北方地区有同样肥效。 相似文献
3.
Field experiments were conducted at Tamil Nadu Rice Research Institute, Aduthurai, India, during the wet seasons of 1992 and 1993 to study the effect of full and partial substitution of fertiliser N with green manure N (Sesbania rostrata) on nitrogen uptake, yield attributes and yield of rice. The experiment consisted of eight treatments with two levels of N (100 and 200 kg ha−1 ) and three sources of N application viz., fertilizer, integrated (1:1 fertilizer and green manure N) and green manure N compared to the recommended practice (150 kg fertilizer plus 6.25 t ha−1 (72 kg N) green manure) and a no N control. Nitrogen application markedly increased the N uptake. Combined use of the two N sources at 200 and 222 kg N ha−1 and of single fertilizer N at 200 kg N ha−1 recorded the maximum N uptake, increased the yield attributes such as number of panicles per unit area, weight per panicle, number of total and filled grains per panicle and test weight. At 200 kg N ha−1 full substitution of N by green manure reduced the grain yield but only partial substitution of N by green manure resulted in almost similar yield as single fertilizer N. Thus 200 kg N ha−1 applied in equal proportions of fertilizer and green manure N can be recommended for medium duration rice cultivars. 相似文献
4.
Two-year field trials with winter wheat cultivars Batis and Toronto were conducted in Southern Bavaria, Germany, to investigate the possible causes of cultivar differences in response to N supply varying in total amount and time of application. Cultivar-related differences in grain yields were observed in treatments with low and medium N supply. High doses of N supply resulted in grain yield adjustment or grain yield advantage for cv. Toronto. The results of this study revealed a consistent, genotypic pattern in response to N fertilization in spite of strong seasonal effects. Systematic modifications in canopy growth rates in response to N supply were of particular relevance and a main factor for differences in tillering intensity resulting in modified stand densities. In the present study, cultivar differences in spike development and interactions with N supply related more to abortion than to initiation processes for number of spikelets and number of flowers per spikelet. High grain density (grains per m2) of cv. Toronto was evident during reproduction stages even under conditions of medium N supply. However, decreased growth rates during the later part of grain filling in combination with low 1000 grain weight, which was barely modified by N fertilization, allowed only partial utilization of this potential. It is assumed that sink limitations were of particular relevance for grain yield development in cv. Toronto, while cv. Batis combined a less intense response to N supply with more stability in the development of grain yield components. 相似文献
5.
矮化中间砧苹果施氮位置对细根分布、氮素吸收和产量品质的影响 总被引:1,自引:0,他引:1
为明确矮化中间砧苹果树合理的施肥位置,减少氮肥的浪费。试验于2018年和2019年,以‘烟富3’苹果/SH6/八棱海棠为试材,借助15N同位素示踪技术,研究了萌芽前在树冠投影范围距树干由近及远的3个水平距离——内环、中环和外环施氮对新梢旺长期细根和土壤15N分布、树体15N吸收以及果实产量和品质的影响。结果表明:各处理的苹果细根(直径≤2 mm)根长密度均在水平方向和垂直方向呈衰减规律,主要分布在距离树干水平方向0~100 cm、垂直方向0~40 cm土层范围;与不施肥(对照)相比,施氮增加了细根根长密度,以施氮区内细根根长密度增加最为显著;从垂直方向0~20 cm土层施氮区细根根长密度增加量来看,内环施氮处理增幅最大,为对照的1.33倍~1.36倍,其次是中环施氮处理。各处理土壤15N含量峰值在水平方向均出现在施氮区域,在垂直方向均出现在0~20 cm土层。不同处理间树体细根根长密度与土壤15N分布空间吻合度(RLD-15N)差异显著,内环施氮处理显著高... 相似文献
6.
【目的】筛选不同温度下烟草花叶病毒(Tobacco mosaic virus,TMV)侵染后枯斑三生烟(Nicotiana tabacum var. Samsun NN)差异表达的长链非编码RNA(long non-coding RNA,lncRNA),研究lncRNA在枯斑三生烟抗性反应中的作用。【方法】N基因的温度敏感性使枯斑三生烟在25℃时具备对TMV的抗性、在31℃抗性丧失,在这两个温度条件下对枯斑三生烟接种TMV和磷酸盐缓冲盐水(phosphate buffered saline,PBS),48 h后提取系统叶总RNA,构建链特异性文库后进行深度测序。对测序结果进行过滤后利用HTSeq将有效数据与近缘品种TN90(N. tabacum var. TN90)基因组比对,筛选得到lncRNA后利用FPKM法估计lncRNA的表达水平。通过edgeR筛选差异表达lncRNA(differentially expressed lncRNA,DElncRNA),并利用qRT-PCR技术对这一结果进行验证。通过共定位及共表达分析预测DElncRNA的靶基因,通过参考基因组注释、GO和KE... 相似文献
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9.
采用不同比例丹参(Salviae miltiorrhiza)药渣替代玉米芯对糙皮侧耳(Pleurotus ostreatus)、毛头鬼伞(Coprinus comatus)供试菌株进行栽培实验.经栽培收获两茬子实体,分别对不同配方两个菌种的菌丝长速、单位料重产量、生物学效率等指标进行统计分析.结果表明:在单位料重产量及生物学效率表现上,随培养料中所含丹参药渣比例增加而增加;在菌丝长速表现上则相反.经丹参药渣、玉米芯的碳氮比分析(28.5∶1;88.1∶1)得知,栽培料中随药渣含量的增加氮素含量相应提高(碳氮比55.27∶1~27.44∶1,氮含量为0.76%~2.43%),成为两个菌种产量增加的主要原因. 相似文献
10.
利用啤酒废水制备微生物絮凝剂研究 总被引:4,自引:5,他引:4
[目的]优化絮凝剂产生菌培养条件,以期获得价廉、高效的絮凝剂。[方法]从某污水处理厂的活性污泥中筛选得到了一株稳定高效的微生物絮凝剂产生菌127号菌种,采用啤酒废水作为廉价培养基,对絮凝剂产生菌127号菌种进行培养,优化其培养条件,考察外加碳源、氮源、培养基pH值、培养时间等因素对菌株絮凝效果的影响。[结果]将啤酒废水稀释10倍后,BOD5为7880 mg/L,无需另外添加碳源,添加尿素1.0 g/L,总氮约为540 mg/L,最佳培养基的初始pH值为5.0,最佳培养时间为48 h,絮凝效果最好,达96.8%。[结论]啤酒废水中含有丰富的营养物质,直接利用啤酒废水作为培养基絮凝剂产生菌127号菌种进行培养,其高岭土悬液絮凝率也达到88.2%,可以大大降低培养成本。 相似文献