4个双低甘蓝型油菜品种干物质积累及养分吸收动态

采用田问试验研究了4种双低油菜整个生育期内干物质积累及氮磷钾养分吸收动态.结果表明:播种后140 d(苗期)、140～170 d(蕾薹期)、170～199 d(花期)和199～212 d(角果期)4个油菜品种的干物质积累比例分别为12.7%～20.9%、15.3%～20.0%、60.3%～71.7%和-27.4%～-9.1%;氮素积累比例分别为33.3%～47.8%、11.9%～14.7%、15.5%～28.1%和17.7%～28.8%;磷素积累比例分别为23.4%～37.9%、22.5%～29.4%、32.7%～54.1%和-17.2%～-3.O%;钾素积累比例分别为24.7%～33.9%、16.2%～35.9%、31.0%～53.3%和-43.0～-23.5%.表明油菜干物质累积与养分吸收量的变化趋势基本相同,氮素积累量最大时期为苗期,干物质、磷、钾积累量最大时期为花期,干物质及氮磷钾养分积累速率最大时期均为花期.每生产100 kg籽粒养分的需求量平均为N 4.3 kg、P2O5 2.7 kg和K2O 8.7 kg.在同等施肥量水平下,4个油菜品种中,华油杂9号籽粒产量最高,达3 574 kg/hm2;N、P、K养分偏生产力顺序为:中双9号>华油杂9号>华双5号>华双4号.     

龙眼叶片营养与成花的相关性

[目的]探索龙眼叶片营养状况与成花的关系。[方法]以石硖龙眼为试材,于1月份采集8个方向末次秋梢倒数第二复叶的第2~3对小叶,测定氮、磷、钾营养含量,计录总梢数和抽花穗总梢数。[结果]龙眼叶片1月份的N、P、K含量分别为1.17%~1.67%、0.13%~0.18%、0.35%~0.66%,平均值分别为1.31%、0.16%、0.53%;N/P为7.15~11.93,平均为8.14;N/K为1.95~4.71,平均为2.59;均与成花有显著的关系。回归分析表明,当1月份龙眼叶片N、P、K含量及N/P、N/K分别为1.42%、0.15%、0.50%、10.42、3.24时,成花效果最好。[结论]1月份龙眼叶片N、P、K含量及N/P、N/K与成花有显著相关性,龙眼1月份叶片P/K与成花不具有显著相关性。     

低磷胁迫下武陵山区糯玉米地方品种的籽粒产量和营养品质效应

以10个来自武陵山区的糯玉米地方品种为材料,设置不施磷和施磷2个处理,研究其对糯玉米地方品种籽粒产量和营养品质的影响,结果表明,低磷胁迫对糯玉米地方品种籽粒产量、蛋白质和亚油酸含量影响较大。籽粒产量、蛋白质和亚油酸含量可作为筛选耐低磷糯玉米种质的指标。低磷胁迫下籽粒产量与营养品质的相关分析结果表明,育种上培育高产优质耐低磷的糯玉米品种是可行的。     

日光温室有机土壤栽培对番茄生长、产量和品质的影响

在日光温室番茄生产中以普通土壤栽培为对照,研究以由腐熟油菜秆、腐熟小麦秆、腐熟羊粪和洁净土壤配制成的有机土壤中番茄生长、生理特性、产量和品质的变化.研究结果表明,有机土壤栽培的番茄生长势好,株高与茎粗均显著优于普通土壤,其营养品质如总糖、番茄红素含量明显优于普通土壤栽培的,而有害物硝酸盐含量低于土壤栽培的.因此番茄有机...     

Characteristics of phosphorus removal in an intermittent aeratedbiofilter under two operating regimes

A fixed film system composed of an anaerobic biofilter and an intermittently aerated biofilter (IABF) was developed for enhanced biological phosphorus removal (EBPR) in the treatment of domestic wastewater. We investigated the influence of the operating regime on the performance of EBPR in IABF. Compared to the sequencing batch regime, net phosphorus uptake capacity in IABF was improved under the aerobic continuous feeding (ACF) regime. An innovative method that can be used instead of traditional backwashing was applied to IABF for removal of phosphorus from the reactor under the ACF regime. Using this method, a stable performance of EBPR was achieved during long term operation, with a low frequency of backwashing in IABF. Distribution and variation of organic and phosphorus in IABF may imply spatial distribution of microorganisms in the column of the reactor under the ACF regime.      

不同有机肥料对番茄生长及品质的影响

在有机生产条件下布置小区试验,研究了有机肥料对番茄生长、养分平衡和果实品质的影响,研究中采用农家堆肥、精制有机肥、沼渣为供试有机肥料,进行等氮投入,其中精制有机肥在此基础上额外设置了3个施肥水平。结果表明：有机肥适量施用能显著促进番茄生长发育,株高、茎粗、开花数、叶绿素含量等指标均好于不施肥对照,增产效果显著。等氮条件下不同有机肥料增产幅度在9.2%-14.4%之间。肥料氮磷钾养分平衡指数分别波动于3.06~3.35、7.77~23.65、1.66~2.88之间,而氮磷钾的利用率则分别波动在7.37%~9.51%、1.49%~4.39%、9.10%~15.32%之间。有机肥投入量的增加并未显著促进作物对氮磷钾的吸收,肥料利用率随施肥量的增加而急剧下降,养分平衡指数上升。适量施用有机肥料增加了番茄可溶性糖、固形物、Vc含量以及糖酸比,降低了硝酸盐含量,从而提高了番茄果实品质。研究揭示,有机废弃物的资源化利用,可以促进作物产量的提高和品质的改善,但过多的有机肥投入无济于产量和品质的进一步增长,相反还可能存在着环境污染风险。     

施肥对甜菜产量、物质积累和养分吸收规律的影响

采用田间试验研究了施肥对甜菜产量、干物质积累和吸肥规律的影响。结果表明：氮、磷、钾肥配合施用可以提高甜菜产量,制约甜菜产量的养分因子依次为N〉P〉K。干物质日积累规律为：苗期增长缓慢,叶和块根分别在出苗后80,125d达到最大值,在60～80d时,块根的日积累量超过叶。氮的吸收速率,全株表现为慢-快-慢的规律,叶片和块根分别在出苗后100,160d达到最大值,氮的累积总量在叶中较多。磷的吸收速率,叶片表现为出苗后40～80d最快,块根在40～120d快速增加并达到最大值;磷在叶和根中的累积量分别在出苗后80,120d达到最大,80d之后根的累积量超过叶。对于钾,叶在出苗后40—120d快速吸收并达到最大值,块根在出苗60d后吸收加快,收获时达到最大;在整个生育期内块根对K的吸收量都低于叶。甜菜单株日吸收N和P量分别在出苗后100,60d达到最大值;K的日吸收量苗期较少,40～80d快速增加达到最大,收获前出现负增长。     

Characterizing nitrogen use efficiency in natural and agricultural ecosystems to improve the performance of cereal crops in low-input and organic agricultural systems

Low-input and organic farming systems have notable differences in nitrogen (N) sources, cycling and management strategies compared to conventional systems with high inputs of synthetic N fertilizer. In low-input and organic systems, there is greater reliance on complex rotations including annual and perennial crops, organic N sources, and internal N cycling that more closely mimic natural systems. These differences in farming system practices fundamentally affect N availability and N use efficiency (NUE) and could impact crop traits and breeding strategies required to optimize NUE. We assess genetic and environmental factors that could assist breeders in improving crop performance in low-input and organic farming systems by examining NUE in natural and agricultural ecosystems. Crop plants have often been bred for high N productivity, while plants adapted to low N ecosystems often have lower productivity and higher levels of internal N conservation. Breeders can potentially combine N productivity and N conservation through the use of elite and wild germplasm. Beneficial genetic traits include the ability to maintain photosynthesis and N uptake under N stress and the ability to extract soil N at low concentrations, perhaps through beneficial associations with soil microorganisms. In addition, breeding for specific adaptation to climactic and management practices so that crop uptake patterns match N availability patterns, while minimizing pathways of N loss, will be critical to improving NUE.     

Comparison of dynamic and static APRI-models to simulate soil water dynamics in a vineyard over the growing season under alternate partial root-zone drip irrigation

In this paper, a two-dimensional (2D) dynamic model of root water uptake was proposed based on soil water dynamic and root dynamic distribution of grapevine, and a function of soil evaporation related to soil water content was defined under alternate partial root-zone drip irrigation (APDI). Then the soil water dynamic model of APDI (dynamic APRI-model) was developed on the basis of the 2D dynamic model of root water uptake and soil evaporation function over the growing season. Soil water dynamic in APDI was respectively simulated by dynamic and static APRI-models. The simulated soil water contents by two models were compared with the measured value. Results showed that values of root-mean-square-error (RMSE) for dynamic APRI-model were less than that of the static APRI-model either in the east side or the west side of grapevine. The average relative error between the simulated and measured value was less than 5% for dynamic APRI-model, indicating that the dynamic APRI-model is better than the static APRI-model in simulating the soil moisture dynamic throughout the growing season under the APDI.