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91.
92.
为明确不同玉米品种机械收获时籽粒的耐破碎性差异和影响籽粒耐破碎性的因素,以13个玉米品种为材料,设置不同收获时间,对不同玉米品种籽粒的破碎率、含水率和硬度等指标的动态变化特征进行研究,分析籽粒破碎率与含水率和硬度的关系,采用积分法评价不同玉米品种籽粒的耐破碎性。结果表明:随收获时间的推迟,籽粒破碎率先快速降低后稍有升高,籽粒含水率逐渐降低,籽粒硬度逐渐增大,且玉米品种间差异显著。破碎率与籽粒含水率符合二次曲线关系,当籽粒含水率为19.70%时破碎率最低;破碎率与籽粒硬度极显著负相关,其中胚乳穿刺强度与破碎率的相关性最高,当籽粒胚乳穿刺强度为88.35 N时破碎率最低;籽粒硬度与含水率呈极显著的负相关关系。降低籽粒含水率进而提高其硬度是增强玉米籽粒的耐破碎能力和降低籽粒破碎率的关键。不同玉米品种籽粒的硬度和耐破碎能力存在显著差异,在含水率相近的条件下,耐破碎能力强的玉米品种均具有较高的籽粒硬度。籽粒硬度指标中的胚乳穿刺强度可作为鉴选宜机械粒收玉米品种的重要指标;参试的所有硬粒型玉米品种、半马齿型‘仲玉3号’、半硬粒型 ‘辽禾308’、‘先玉1171’和马齿型‘正红6号’的籽粒耐破碎能力强,可作为适宜机械粒收的品种。 相似文献
93.
《Journal Of Applied Aquaculture》2013,25(3-4):83-100
Abstract Two experiments were conducted to evaluate the effects of microbial phytase in corn distiller's dried grain with solubles (DDGS) on apparent digestibility coefficients (ADCs) and growth performance of rainbow trout, Oncorhynchus mykiss. In experiment 1, DDGS was supplemented with phytase at 0,300,600,900, and 1200 FTU/kg diet. A total of 180 fish (129.1±9.3 g) were stocked into six 140-L tanks with 30 fish/tank. Fish were assigned randomly to a reference diet and each of the 5 diets containing DDGS. Yttrium oxide was used as an inert marker. Results showed that ADCs in DDGS supplemented with different dosages of phytase were: dry matter, 49.1-58.6%; crude fat, 78.9-88.9%; crude protein, 80.0-91.9%; gross energy, 50.5-66.6%; minerals, -7.3-99.7%; and amino acids: 73.9 to 96.8%. In experiment 2, abasal diet containing 15% DDGS supplemented with lysine and methionine was used to determine if trace mineral supplemental levels in rainbow trout diets could be reduced if microbial phytase was supplemented. Six diets were made with trace mineral premix supplementation at 0.1, 0.08, 0.06, 0.04, 0.02, and 0%. Phytase was not supplemented in the basal diet, but supplemented at 500 FTU/kg diet in all other diets. Ten-week results showed that there were no significant differences in fish weight gain, feed conversion ratio, and survival (P < 0.05). There were no significant differences in fish body composition and apparent nutrient retention among fish fed all diets, except that fish fed a diet without trace mineral supplementation had the lowest zinc level and the highest manganese retention. Results indicated that phytase was effective in releasing most of minerals, and that trace mineral supplementation level could be reduced when phytase was used in rainbow trout diets. 相似文献
94.
早春不同时期灌水对小麦耗水特性和产量的影响 总被引:2,自引:0,他引:2
为了提高小麦水分利用效率,针对小麦早春灌水较早的现象,以大面积应用的小麦品种周麦18为材料,设置早春起身期、拔节期灌第1水和全生育期不灌水3个处理,研究早春不同时期灌水对小麦水分利用和产量形成的影响。结果表明,与不灌水相比,起身期和拔节期灌水分别增加耗水量16.77%和14.70%,水分利用效率提高13.13%和19.38%,显著增加了成穗数、千粒重和籽粒产量,对穗粒数影响较小;早春灌水处理间水分利用效率和边际效应以拔节期灌水高于起身期灌水,分别提高5.52%和29.64%,产量及其构成因素差异不显著。因此,适时延迟灌早春第1水,能够改善小麦耗水特性、提高籽粒产量。 相似文献
95.
唐书泽 《湖南农业大学学报(自然科学版)》1993,(5)
采用现代膨化技术,利用本地廉价植物蛋白资源,对谷物进行营养强化,试制了C_1和B_2 2种高蛋白营养膨化最优食品,其蛋白质含量分别为14.2%与15.7%,PER 值达2.36和2.17.同时还试制了A_2,B_1,A_1和C_2 4个推荐产品,其营养价值均超过了FAO/WHO 规定的标准. 相似文献
96.
97.
98.
Nitrogen (N) deficiency is one of the most yield-limiting nutrients in upland rice growing regions word wide. A greenhouse experiment was conducted with the objective to evaluate nineteen upland rice (Oryza sativa. L.) genotypes for N use efficiency. The soil used in the experiment was an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg?1 of soil (high level). Grain yield and yield components and N uptake parameters were significantly affected by N and genotype treatments. Regression analysis showed that plant height, shoot dry weight, number of panicles per pot, number of grains per panicle, grain harvest index, N uptake in shoot and grain were having significant positive relation with grain yield. Nitrogen concentration of 6.4 g kg?1 in the shoot is established as deficient level and 9.5 g kg?1 as sufficient level at harvest. Agronomic efficiency of N (grain yield/unit of N applied) and N utilization efficiency (physiological efficiency X apparent recovery efficiency) were significantly different among genotypes. These two N use efficiencies were having significant quadratic relationship with grain yield. Soil pH, exchangeable soil Ca and base saturation were having significantly positive association with grain yield. However, soil extractable phosphorus (P), potassium (K), hydrogen (H+), aluminum (Al) and cation exchange capacity were having significantly negative association with grain yield. 相似文献
99.
山西省西山地区退耕还林还草后续产业的发展与保障问题分析 总被引:1,自引:0,他引:1
赵艺学 《中国生态农业学报》2012,20(3):378-383
本文通过随机抽取5个典型县区的有关数据,从退耕与林草建设的模式入手,利用比较和综合分析的方法,分析了山西省西山地区以林牧业发展为主的退耕还林还草后续产业的现状和趋势,以及后续产业发展的保障性等问题。结果认为,从整体上看,山西省西山地区退耕还林还草后续产业发展过程可分为倒退式发展(2000—2003年)、明显加快发展(2003—2006年)和迅速发展(2006—2009年)3个时段。选定的典型县区总体情况表明,在区域耕地减少、人口增多的情况下,粮食总产量和人均粮食产量均有所增长,表明典型区域耕地质量明显提高和后续产业持续发展的趋势;从典型县区个案情况看,在某一定时段内粮食总产量和人均粮食产量均出现不同幅度的负增长态势,也显示了该区后续产业存在严重的发展问题。最后提出了稳定耕地数量、保障人均粮食拥有量是后续产业发展的根本,以及需要进一步分析的主要问题。 相似文献
100.
B. GLENCROSS D. BLYTH S. TABRETT N. BOURNE S. IRVIN M. ANDERSON T. FOX‐SMITH R. SMULLEN 《Aquaculture Nutrition》2012,18(4):388-399
This study examined the digestibilities of whole diets and ingredients of a range of starch/cereal grains when fed to barramundi (Lates calcarifer). The ingredients included wheat, oats, sorghum, triticale, barley, among others. Twelve diets were prepared using a twin‐screw extruder to mimic modern aquafeed‐manufacturing processes. The diets were then fed to juvenile barramundi and the faeces collected using stripping methods. Significant variability in the digestible energy and starch value was seen among the test ingredients and diets. Diet starch digestibility ranged from 49.1% to 93.9%. Ingredient starch digestibility ranged from 18.0% to 96.5%. Among the different starch ingredients, a strong negative correlation between the ingredient amylopectin content and starch digestibility of that ingredient was observed. This relationship was also mirrored by a similar relationship, although not as strong, between total starch and starch digestibility. This study demonstrates that barramundi have limited ability to digest starch and that there is an effect of inclusion level on the ability of the animal to digest this nutrient. But it also demonstrates that there is a wide range of cereal sources that can be effectively used as starch sources in extruded diets for this species. 相似文献