分期播种对拟高粱叶片生长和干物质积累的影响

拟高粱出叶速度和地上部干物质(DM)增长受播期的影响。叶龄与播种至该叶片出现期内>10℃活动积温呈极显著的正相关(r=0.9705)。播种至第1叶龄需积温327～355℃。地上部DM积累过程符合Logistic生长曲线。春播拟高粱播种后DM缓慢增长期较夏播长,但DM积累高峰期出现早且持续时间较长,因而其DM产量高于夏播。秋后拟高粱DM的积累主要是由于茎DM的增长,叶片DM则呈下降趋势。地上部DM(W)积累过程与积温(∑T)的关系可用方程w=K/(1+a·e~(-b∑T))来描述、表明积温的高低决定了拟高粱地上部DM的产量。播期极显著地影响拟高粱的饲草产量,春播各播期间产草量差异较小,但均极显著地高于夏播。本文还讨论了拟高粱在南京的适宜播种期及栽培利用的适宜地区。     

不同播期对玉米品种桂单589产量及性状的影响

[目的]明确玉米品种桂单589的适时播期,为高产栽培提供依据。[方法]试验设置春季6个播期,秋季4个播期,研究不同播期对桂单589生育进程、植株性状、产量性状的影响。[结果]桂单589在春季播种,随着播期的推迟,桂单589播种～出苗时间及生育期缩短,产量逐渐下降;在秋季播种,桂单589生育期随着播期的推迟,出苗期和生育期延长,产量先升后降。在2月中旬～3月中旬,8月上旬～中旬播种,桂单589植株性状、果穗性状及结实性好,产量较高;春季在2初播种,容易遇低温,影响出苗,在3月下旬以后播种生育期明显缩短,散粉期及灌浆期容易遭到高温干旱,秋季9月份后播种,由于后期低温,玉米难以成熟,产量低,影响收获。[结论]桂单589在南宁地区露地大田直播栽培宜安排在2月中旬～3月中旬、8月上旬～中旬播种,在这个时段内播种容易避开或减少季节性自然灾害,能获得较高的产量。     

西昌白皮洋葱品种春播秋收栽培试验

在3个不同的播期对中日照白皮洋葱品种12C1进行栽培对比试验.试验结果表明,中日照白皮洋葱品种12C1适宜在西昌春播秋收,最适播种期为1月19日,最适收获期为8月14日.     

不同播期对西蒙185产量影响的研究

2021年在陕西渭南地区以玉米西蒙185为供试材料,共设置8个播期,研究播期对西蒙185果穗性状及产量的影响,确定西蒙185的最佳播期,旨在为西蒙185的高产栽培及进一步的推广应用提供理论支撑。研究发现,随着播种时间的推迟,玉米产量呈现出先上升后下降的趋势,在5月8日播种的玉米产量最高,达到12 204.00 kg/hm²。经回归分析发现最佳播期在5月8日～18日之间。     

The effect of nitrogen fertilization on plant growth and the nitrate content of leaves and roots of parsley in the Mediterranean region

Curly-leafed and turnip-rooted parsley have recently been introduced to Greece as alternative herbs within the programme for crop diversification. Because the response of these subspecies to nitrogen (N) application under the warm climatic conditions of the Mediterranean region is unknown, both were cultivated over three consecutive years in order to evaluate their yield potential and quality (in terms of nitrate content) in relation to nitrogen application in comparison with the traditionally cultivated plain-leafed subspecies. Nitrogen was applied as ammonium nitrate in the form of liquid feeds at rates of 30–450 mg kg⁻¹. Foliage and root yield increased with N application up to a level of 150 mg kg⁻¹ and the nitrate content of the tissues was low. Increasing N application rates to 300 or 450 mg kg⁻¹ did not cause a further increase in yield, but the nitrate content of the tissues increased. In view of health concerns with respect to human nitrate intake and environmental threats posed by excessive N application, it is concluded that the optimum level of ammonium nitrate application under local conditions should be 150 mg kg⁻¹. Overall, all three subspecies responded to N in a similar way in terms of yield and nitrate content.     

不同播期对黄秋葵生长及发育的影响

研究了6个不同播期对黄秋葵生长发育的影响。结果表明,播期在3月24～31日,对黄秋葵株高、茎粗、叶面积、折算产量、果形和品质均有明显的促进作用;播期在3月11～18日,对黄秋葵茎粗、分枝数和折算产量也有作用,并降低第一果节位,但果实畸形率高;播期在4月7～14日,对黄秋葵株高和果实品质有作用,但折算产量明显较低。     

地膜穴播冬小麦播期、密度效应

1996－1997年,在山西省临汾应用裂区设计法就各小麦地膜穴话的播期、密度进行了研究。结果表明,主因子播期A2（9月28日）与播期A1（9月21日）、播期A3（10月5日）的产量存在5％显著差异;副因子播量4个水平均存在5％显著差异;播期和播量间存在互作效应,以A2（9月28日）B2（297万位／hm2）组合产量最高,达4900．5kg／hm2。同时,对同一播期下、不同播量的土壤耗水规律及子粒灌浆速度进行了研究,为地膜冬小麦合理选择播期、密度提供了理论依据。     

垄作栽培对夏玉米根系和叶片生长发育及产量性状的影响研究

研究了不同栽培方式对夏玉米根系及叶片生长发育和主要产量性状的影响。结果表明：垄作栽培夏玉米与传统平作栽培相比,根系发达,0～50 cm土层各层次根系干重均增加;各叶位叶片宽度增加,长度基部1～5叶位缩短、中上部增加;各期叶面积系数都较大。垄作栽培比传统平作增产12.1%。     

Type and time of autumn tillage with and without herbicides at reduced rates in southern Sweden: 2. Weed flora and diversity

The design of integrated weed management (IWM) systems is essential in order to reduce the use of herbicides for crop production. By combining different weed management practices, herbicides may be used at lower doses than normally recommended, while still maintaining acceptable weed population levels. The purpose of this study was to develop tillage strategies, with and without herbicides at reduced rates, appropriate for different weed populations. The influences of type and time of stubble cultivation, harrowing and mouldboard ploughing on the weed flora were followed during 1988–1994 in eight long-term field trials situated in southern Sweden. Spring-sown barley (Hordeum distichon L.) and oats (Avena sativa L.) dominated the crop rotations. Herbicides were either omitted or used at ca. 50% of a full dose. The perennial species Sonchus arvensis L. was favoured by omittance of ploughing but was better controlled by late ploughing not preceded by stubble cultivation; the reduction in the latter treatment being 74%. Stubble cultivation succeeded by ploughing reduced biomass of Elymus repens (L.) Gould. by 90% compared with ploughing solely. Early ploughing reduced the biomass of the species by 50% compared with late ploughing. The species Cirsium arvense (L.) Scop. was highly favoured by early ploughing followed by late autumn harrowing, the biomass of the species being six-fold higher than in other treatments. Compared with other treatments, stubble cultivation favoured four annuals but efficiently controlled three others, while omittance of ploughing favoured six annual and two perennial weed species. Late ploughing not preceded by stubble cultivation favoured four annual and one perennial species, while early ploughing was more efficient than late ploughing in controlling two of the annual species. Influences of treatments on weed species were frequently moderated by interspecific competition resulting in inconsistent response at different sites. Herbicides reduced the number of species by three, from 11 to eight species, averaged across sites and tillage systems. Influences of treatments on diversity were not consistent, since weed floras differed between sites and since some of the species responded inconsistently to tillage and herbicides. This study shows that by utilizing appropriate tillage strategies it is possible at many sites to maintain acceptable weed population levels, although herbicides are used at 50% lower doses than is normally recommended. The timing and type of tillage have to be chosen for being as efficient as possible to the most troublesome weed species at a site.     

连翘地膜覆盖播种育苗技术

为解决连翘春栽出苗慢、出苗不齐、缺苗多的问题,采用秋季播种育苗,并进行了地膜覆盖、麦秸和稻草覆盖对比试验,试验结果表明,地膜覆盖的连翘生态效应十分明显,出苗率和苗木质量也明显高于麦秸覆盖和稻草覆盖。