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71.
HUANG Ping ZHANG Jia-bao XIN Xiu-li ZHU An-ning ZHANG Cong-zhi MA Dong-hao ZHU Qiang-gen YANG Shan WU Sheng-jun 《中国农业科学(英文版)》2015,(1)
Cropland productivity has been signiifcantly impacted by soil acidiifcation resulted from nitrogen (N) fertilization, especialy as a result of excess ammoniacal N input. With decades’ intensive agricul... 相似文献
72.
73.
Response of confection sunflower (Helianthus annuus L.) grown in a semi‐arid environment to planting date and early termination of irrigation
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V. R. Joshi J. J. Heitholt A. Garcia y Garcia 《Journal of Agronomy and Crop Science》2017,203(4):301-308
Adjustments on planting date and on the time to terminate irrigation may reduce agricultural water use. However, such management practices in regions with extreme weather conditions have the potential to negatively affect yield. A 3‐year (2012–2014) study was conducted on a clay‐loam soil in a cool, semi‐arid environment to (i) determine the response of confection sunflower to planting date and irrigation termination timing and (ii) identify the relative importance of yield components in irrigated confection sunflower across planting dates. Early May planting had considerable negative effects on all studied variables, except on the percentage of large seeds. The highest yield of total and large seeds was obtained from the late May plantings, averaging 3,777 and 3,379 kg/ha, respectively. None of the irrigation strategies affected the measured variables. However, the interaction between planting date and termination of irrigation significantly affected the 1,000‐seed weight. Our study revealed the last week of May as suitable planting period for confection sunflower in the semi‐arid north‐western region of Wyoming, USA, and that irrigation on heavy soils may be terminated as early as at R5.5 stage without a significant yield reduction. The path‐coefficient analysis indicated head diameter and the number of seeds per head as important traits that significantly influence the yield of confection sunflower across planting dates. 相似文献
74.
Evaluation of Cold Tolerance in NERICAs Compared with Japanese Standard Rice Varieties at the Reproductive Stage
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C. M. Wainaina Y. Inukai P. W. Masinde E. M. Ateka H. Murage M. Kano‐Nakata Y. Nakajima T. Terashima Y. Mizukami M. Nakamura T. Nonoyama N. Saka S. Asanuma A. Yamauchi H. Kitano J. Kimani D. Makihara 《Journal of Agronomy and Crop Science》2015,201(6):461-472
New Rice for Africa (NERICA) is a general name for interspecific rice varieties derived from a cross between the high‐yielding Asian rice (Oryza sativa L.) between locally adapted African rice (Oryza glaberrima Steud.). Eight NERICAs were evaluated for cold tolerance (CT) at the reproductive stage and compared with their O. sativa parents and three Japanese standard rice varieties over 3 years. Cold tolerance was evaluated based on the filled grain ratio (FGR) after cold water irrigation. The FGR was greatly reduced by cold water irrigation. NERICA 1, 2 and 7 had higher FGR (51.9–57.9 %), while NERICA 6, 15 and 16 had lower FGR (6.2–14.5 %). NERICA 1, 2 and 7 were less affected by cold stress, with a 31 % mean reduction in FGR, while NERICA 6, 15 and 16 were greatly affected, with their FGRs being reduced by more than 80 %. NERICA 3 and 4 were moderately affected by cold stress, with about 45 % reduction rate in FGR. FGR significantly influenced the grain weights of the varieties with strong positive correlations (r = 0.83–0.91; P < 0.001), and thus, similar trends in grain weights were observed. Grain weights were reduced by 61.7–96.4 % under cold stress. NERICA 1, 2 and 7 showed significantly better performance than NERICA 3 and 4, while NERICA 6, 15 and 16 performed poorly under cold water irrigation. The Japanese varieties Koshihikari (very tolerant) and Ozora (moderately tolerant) were more affected by cold water irrigation than NERICA 1, 2 and 7. On the basis of the mean reduction rate (%) in FGR under cold stress, the varieties were classified as follows: NERICA 1, 2 and 7 as tolerant; NERICA 3 and 4 as moderately tolerant; and NERICA 6, 15 and 16 as susceptible to cold stress. However, NERICA 7 grain yields were lower under cold stress due to both greatly reduced number of panicles per plant and number of spikelets per panicle. Therefore, NERICA 1 and 2 are suitable candidates for production in the highland regions of East Africa and should be promoted for production. 相似文献
75.
多品种叶面肥水稻田间应用效果探析 总被引:1,自引:0,他引:1
[目的]为大面积推广应用多品种叶面肥提供科学依据。[方法]在水稻作物上施用不同品种的叶面肥产品,对比不同叶面肥产品在水稻上的应用效果和经济效益。[结果]在抽穗阶段喷施根外生长调节剂,取得较明显的效果。[结论]根外追肥取得良好的效果,可以继续推广。 相似文献
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77.
[目的]为速生桉树木材液化及其产物的应用提供参考。[方法]以硫酸为催化剂,苯酚为液化剂,对速生人工林桉树木材进行液化,并取液化产物与甲醛进行树脂化反应制备液化木基酚醛树脂LWPF,研究液比对液化反应效率、液化产物重均分子量及LWPF树脂胶合性能的影响。[结果]随着液比的提高,液化产物的残渣率及重均分子量均降低,而LWPF树脂制得的胶合板的木破率提高;当液比提高到一定程度后,液化产物的残渣率和重均分子量及LWPF树脂所制胶合板的木破率变化不明显。[结论]对速生桉树木材的液化工艺及其液化产物的树脂化合成工艺进行了优化。 相似文献
78.
《动物营养(英文)》2020,6(1):80-84
This experiment was conducted to investigate the effects of dietary lipid-to-carbohydrate ratio on growth and carbohydrate metabolism in juvenile cobia (Rachycentron canadum). Six isonitrogenous diets were prepared to vary in lipid-to-carbohydrate ratio (g/g) as follows: D1, 2.26; D2, 1.31; D3, 0.78; D4, 0.47; D5, 0.34; and D6, 0.23. Cobias were fed to satiety for 8 weeks. The weight gain and protein efficiency ratio in D1 group were significantly lower than those in other groups (P < 0.05), accompanied by a lower level of feed conversion ratio (P < 0.05). Protein retention efficiency in D4 and D6 and whole body protein in D4 and D5 were significantly higher than those in D1 group (P < 0.05). Survival rate in D4 group was the highest among all groups and was significantly higher than that in D1, D2 and D5 (P < 0.05). In terms of serum triglyceride, D1 and D2 were significantly higher than D6 (P < 0.05). Hepatosomatic index in D3 and D4 was significantly lower than that in D1 (P < 0.05). Fructose-1,6-diphosphatase in D4 was significantly higher than that in D1 and D3 (P < 0.05). Phosphofructokinase in D3 and D4 and malic enzyme in D4 and D5 were significantly higher than those in other groups (P < 0.05). Results indicate that cobia utilizes carbohydrates as energy source more efficiently than it utilizes lipids. The optimal lipid-to-carbohydrate ratio in juvenile cobia diets is 0.47. 相似文献
79.
种植密度对滴灌马铃薯生长、产量的影响 总被引:1,自引:0,他引:1
为了了解耕培土滴灌条件下种植密度对马铃薯生长、产量以及水分利用效率的影响.试验共设密度分别为7.28×104 株/hm2(RS25),6.67×104 株/hm2(RS35),5.55×104 株/hm2(CK)3个处理.结果表明:随着种植密度的增加,株高、茎粗、干物质积累量以及商品薯率均有降低的趋势;产量、水分利用效率随种植密度的增加表现出先增大后减少,其中RS35处理产量和水分利用效率均表现最高,分别达到47 325 kg/hm2和12.05 kg/m3;在马铃薯品质方面,种植密度对马铃薯粗蛋白含量的影响不具有统计学意义;淀粉和维生素C随着密度的大幅增加而降低,其中RS25处理的淀粉较CK降低了5.57%,RS25处理的维生素C较CK降低了7.96%,同时RS35与CK处理不具有统计学意义.综上所述,种植密度为6.67×104 株/hm2的RS35处理马铃薯高产优质,且水分利用效率最高,为黑龙江地区滴灌马铃薯较为适宜的种植密度. 相似文献
80.
为探讨楸树无性系对氮素的吸收、分配及利用特性,以2年生楸树无性系015-1、1-3、7080、1-4和004-1组培苗为试验材料,应用15N示踪技术对楸树无性系进行施肥试验。结果表明,5个楸树无性系氮肥的吸收率、利用率及分配率具有较强的一致性,氮肥利用率介于27.14%~31.24%之间。楸树无性系根和叶的肥料氮比例(Ndff)明显大于茎,楸树无性系根和叶对氮肥的竞争力较强,茎对氮肥的竞争力最弱。015-1茎部氮素分配率及无性系7080根部氮素分配率明显高于其他4个无性系;氮素分配率在各个器官中差异显著,叶片氮素的分配率最高,总体趋势为叶根茎。本研究结果为楸树氮肥的合理施用提供了理论依据。 相似文献