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排序方式: 共有411条查询结果,搜索用时 343 毫秒
41.
This study aimed to evaluate the productivity of Arundo donax under good water and N availability coming from non-conventional sources, in different Italian environments (Padova and Bologna in the north, Reggio Calabria and Catania in the south) in relation to three harvest periods (autumn; mid-winter; late-winter).In the northern locations A. donax had already reached maximum productivity the year after transplanting, with 85 and 98 t ha−1 of dry matter at Padova and Bologna, respectively. At Reggio Calabria and Catania a further biomass increase was obtained from the second to third year of cultivation, when production was 62 t ha−1 and 51 t ha−1, respectively.The average dry matter production was 74, 66 and 65 t ha−1 with autumn, mid-winter and late-winter harvesting, respectively.Under N input ranging from 225 to 329 kg ha−1 year−1 at the different locations, the apparent N balance (input–output) was negative except in Catania indicating a great potential of A. donax to provide high N uptake, which would be a useful feature in environments under the European Nitrates Directive. 相似文献
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《Plant Production Science》2013,16(3):203-210
SummaryGenerally F1 hybrids from crosses between japonica and indica rice show variable degrees of sterility. Previous studies revealed that among the indica rice, the Aus type has sexual affinity with japonica cultivars giving higher fertility in F1 hybrids. Therefore, we made an effort to obtain higher grain yield by producing F1 hybrids between japonica and Aus-type indica. A field experiment was conducted to investigate the heterosis in these F1 hybrids for dry matter accumulation, spikelet fertility, yield and yield attributes, to find cross combinations with higher grain yield, and examined the relationships of grain yield with some agronomic characters. F1 hybrids flowered earlier than their parent cultivars. Heterosis for dry matter accumulation was positive at the panicle initiation stage, at heading and at maturity. The average heterosis for number of panicles, grain and straw yield per plant, number of spikelets per panicle and 1000-grain weight was positive. A few F1 hybrids showed positive heterosis for number of filled grains per panicle, spikelet fertility and harvest index; but the average heterosis for these traits was negative. Among the yield components, a higher number of panicles per plant and higher number of spikelet per panicle contributed to higher grain yield in F1 hybrids. A significant and positive relationship existed between spikelet fertility and grain yield per plant. The higher grain yield was attributed to higher dry matter production rather than higher harvest index in F1 hybrids, although low spikelet fertility limited yield potential in some F1 hybrids. 相似文献
44.
氮肥不同施入量对水稻新品种富友33生育及产量的影响 总被引:1,自引:0,他引:1
采用小区对比试验方法,探讨了氮肥不同施入量对水稻新品种富友33生育及产量的影响。结果表明,增加氮肥施入量,可促进富友33单位面积收获穗数、齐穗期叶面积指数与剑叶净光合速率、成熟期干物质积累量的增加;不利于其成穗率、齐穗期高效叶面积率与有效叶面积率、齐穗后干物质积累量占籽粒产量百分比以及收获指数的提高。在本试验条件下,施氮量(N)240.0 kg/hm2的处理E3获得单产9.22 t/hm2,比E4、E2、E5、E1处理分别增产了0.2%、3.1%、3.4%和7.3%。 相似文献
45.
Forest disturbance and recovery are critical ecosystem processes,but the temporal patterns of disturbance have not been studied in subtropical China.Using a tree-ring analysis approach,we studied post-logging above-ground(ABG)biomass recovery dynamics over a 26-year period in four plots with different degrees of logging disturbance.Before logging,the ABG biomass ranged from 291 to 309 t ha-1.Soon after logging,the plots in primary forest,secondary forest,mixed forest and singlespecies forest had lost 33,91,90 and 100%of their initial ABG biomass,respectively.Twenty-six years after logging,the plots had regained 147,62,80 and 92%of their original ABG biomass,respectively.Over the 26 years following logging,the mean CAI(Current annual increment)were 10.1,5.5,6.4 and 10.8 t ha^-1 a^-1 and the average MAI(Mean annual increment)8.7,2.5,5.6 and 7.8 t ha^-1 a^-1 for the four forest types,respectively.The results indicate that subtropical forests subjected to moderate logging or disturbances do not require intensive management and single-species plantings can rapidly restore the above-ground biomass to levels prior to heavy logging. 相似文献
46.
茬次和一天内不同收获时间对紫花苜蓿青贮发酵质量和体外发酵参数的影响 总被引:1,自引:0,他引:1
为了研究茬次和一天内不同收获时间对紫花苜蓿青贮饲料品质的影响,并进一步评价其饲用价值,本试验采用双因素设计,两茬紫花苜蓿于现蕾期同一天08:00(AM),13:00(M)和18:00(PM)刈割并调制青贮饲料,室温下保存45 d后,取样分析并采用体外发酵法评价其饲用价值。结果表明,第1茬紫花苜蓿青贮饲料的相对饲喂价值(relative feed value,RFV),干物质体外消化率(in vitro dry matter digestibility,IVDMD)及体外发酵挥发性脂肪酸(volatile fatty acids,VFA)、产气量均显著高于第2茬(P<0.05)。下午收获的紫花苜蓿青贮饲料有更高的干物质(dry matter,DM)含量及IVDMD (P<0.05)。因此,在实践生产中,要抓好第1茬的苜蓿生产,推迟刈割时间至中午或下午,可获得更高品质的紫花苜蓿青贮饲料。 相似文献
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48.
机械粒收是玉米生产发展的方向,是降低玉米生产成本提高市场竞争力的重要措施。黄淮海区玉米目前处于机械粒收技术示范推广的关键时期。本研究通过分析一年两地持续阴雨对不同播期玉米品种机械粒收质量的影响,为该技术的推广应用提供参考。试验选用华美1号、郑单958、登海605为材料,分析持续阴雨天气下播期、品种、密度对机械粒收质量的影响。结果表明,在持续降雨条件下,播期、品种和密度间的子粒含水率、破碎率存在显著差异,品种间的杂质率差异显著,品种、密度间的田间损失率差异显著。综合比较,持续阴雨天气条件下,子粒含水率是影响机械粒收质量的关键因素,主要通过影响子粒破碎率影响收获质量。 相似文献
49.
不同熟期小麦品种收获指数(HI)的遗传研究 总被引:8,自引:2,他引:6
采用Criffing方法I,利用6×6完全双列杂交,对不同熟期冬小麦品种收获指数(HI)的遗传机制进行了初步探讨。结果表明:HI的GCA效应、SCA效应和R效应均达到极显水平,其均方比为1.804:0.384:1;HI遗传以加性基因效应占优势,但反交效应和非加性基因效应也不可忽视;加性基因效应对后代HI的提高因亲本而异,在该性状的遗传改良中存在着母体效应;HI的广义遗传力的92.44%,狭义遗传 相似文献
50.
北疆玉米大田机械粒收质量调查 总被引:1,自引:0,他引:1
北疆是我国玉米机械粒收率最高的区域,为了解北疆玉米大田粒收质量现状,2012-2017年在新疆奇台总场、伊犁新源71团、伊宁县和温泉县等地农户田块调查了机械粒收质量,共获得269组样本,结果表明:(1)子粒破碎率均值为6.38%,高于5%的国家标准[玉米收获机械技术条件(GB/T 21961-2008)]要求;杂质率和产量损失率均值分别为0.41%和0.96%,分别低于3%和5%的国家标准要求,子粒破碎率高是当前北疆玉米大田机械粒收存在的主要质量问题。(2)收获玉米子粒含水率均值为23.3%,其与破碎率呈显著相关,可用二次函数y=0.0263x 2-1.0433x+15.867(R 2=0.108,n=269)拟合。(3)在子粒含水率相同条件下,不同品种之间子粒破碎率表现出明显差异,其中,新引M751子粒破碎率明显低于KWS2564,而KX3564介于两者之间。(4)筛选早熟、脱水快、耐破碎品种,实施玉米密植高产全程机械化绿色生产,可以有效改善机械粒收质量,实现玉米高产高效协同。 相似文献