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提出了双季稻区汕优６３、特优６３再生制种可行的花期安排及提高再生季异交结实率的有效措施．并讨论了再生季花期调控的有关问题． 相似文献
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为探究关中平原地区不同作物茬口对冬油菜养分积累和产量的影响,通过两年田间试验,研究分析不同
茬口,包括休闲茬口（FW）、大豆茬口（SW）、毛苕子茬口（HW）和玉米茬口（MW）对冬油菜土壤养分含量、地上部干
物质积累、分配和氮磷养分吸收积累、产量构成因素以及产量的影响,筛选冬油菜生产适宜的前茬作物,为加强冬
油菜生产,提高土地利用效率提供理论依据。结果表明：与休闲茬相比,大豆茬、毛苕子在冬油菜关键生育时期土
壤碱解氮、硝态氮、铵态氮、速效磷含量均显著提高,其中以大豆茬提升土壤养分效果最为明显,而玉米茬各土壤养
分含量均有所下降;大豆茬、毛苕子茬冬油菜地上部干物质积累量较休闲茬分别提高26.05%、13.12%,玉米茬下降
2.74%;氮素积累量较休闲茬分别提高30.86%、14.86%;磷素积累量较休闲茬分别提高37.03%、20.35%,玉米茬氮、
磷素积累量较休闲茬降低12.76%、3.48%;与休闲茬相比,大豆茬、毛苕子茬冬油菜籽粒产量显著提高29.48%、
17.77%,玉米茬与休闲茬冬油菜产量差异不显著。相关性分析结果表明,大豆茬、毛苕子茬增产归因于土壤养分、
地上部干物质积累量、氮磷养分积累量以及单株角果数的增加。因此,在关中平原地区,大豆、毛苕子是冬油菜生
产适宜前茬作物,而大豆是提高冬油菜籽粒产量、氮磷养分积累的理想前茬作物。 相似文献
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J. Lewis 《Grass and Forage Science》1959,14(4):285-292
This investigation was carried out with leafy varieties of perennial ryegrass at four centres near Aberystwyth over a period of three years. Nitrogen applied in spring increased lodging, the number of fertile tillers and also seed yield, except where sowing was made without a cereal cover crop. While reasonable yields were obtained from badly laid crops, it is suggested that lodging prior to anthesis has an adverse effect on seed yield. Clover included as a companion species tended to depress the yield of seed and increase the degree of lodging.
Seed rate had less infiuence on lodging and seed yield, but the data show that similar yields were obtained from light seed rates of 4 lb. per acre as from the heavier rates. On the other hand, there was a tendency for the low rate of seeding to produce weedy plots, especially when sown in the absence of a cover crop. 相似文献
Seed rate had less infiuence on lodging and seed yield, but the data show that similar yields were obtained from light seed rates of 4 lb. per acre as from the heavier rates. On the other hand, there was a tendency for the low rate of seeding to produce weedy plots, especially when sown in the absence of a cover crop. 相似文献
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《Journal of Crop Improvement》2013,27(1):145-168
Summary Weeds continue to have major impacts on crop production in spite of efforts to eliminate them. Most weed species rely on seed for regeneration and persistence. The species composition and density of weed seed in the soil vary greatly and are closely linked to the cropping history of the land. Altering tillage practices changes patterns of soil disturbance and weed seed depth in the soil, which plays a role in weed species shifts. Crop rotation and weed control practices also impact the weed seed bank in the soil. Information on the weed seed bank should be a useful tool for integrated weed management. Decision aid models are being developed that use information on the composition of the weed seed bank to estimate weed populations, crop yield loss, and to recommend weed control tactics. Understanding weed seed bank dynamics can also be used to guide management practices. Improving and applying our understanding of weed seed and seed bank dynamics is essential to developing improved weed management systems. 相似文献
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Shinji Sawano Toshihiro Hasegawa Shinkichi Goto Pisarn Konghakote Anan Polthanee Yasushi Ishigooka Tsuneo Kuwagata Hitoshi Toritani 《Paddy and Water Environment》2008,6(1):83-90
Rain-fed lowlands are major agricultural ecosystems used for rice production in Northeast Thailand. Developing a tool to assess
the effects of variable water conditions on the regional scale yield is also important to predict the effects of climate change
on food supply. To estimate regional yields, we need a simple but accurate measure of the crop calendar (i.e., the distribution
of planting dates), which has a strong influence on grain yield. In this article, we modeled the dependence of the crop calendar
on rainfall patterns based on a survey of the region’s farmers as a part of an effort to provide a stronger basis for regional
yield estimates. Our survey, conducted in 11 provinces for 2 years, confirmed the existence of large windows for sowing and
transplanting versus narrow windows for heading and harvesting for rain-fed lowland rice culture in all the provinces. Variable
water, soil, and toposequential conditions in the paddy fields were responsible for the large sowing and transplanting windows,
whereas the use of photoperiod-sensitive varieties explained the narrow windows for heading and harvesting. The crop calendar
was well expressed as a function of cumulative precipitation from June onward. When the crop calendar model was combined with
a simple phenology-based model that uses growing degree-days adjusted by a day-length factor, we could estimate the rice crop
calendar under rain-fed lowland conditions with acceptable accuracy. The model described in this article will be combined
with a crop growth model to improve regional yield estimates for rain-fed lowland rice. 相似文献
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Marisol T. Berti Burton L. Johnson Robert A. Henson 《Industrial Crops and Products》2008,27(3):272-278
Cuphea viscosissima Jacq. × C. lanceolata f. silenoides W.T. Aiton is a new crop being developed in the north-central USA as an industrial oilseed crop. Adequate plant stand is essential for successful commercial production of cuphea. The objective of this study was to determine the effect of seeding date, depth and soil packing on stand establishment and subsequent crop performance. The study was conducted at Carrington and Prosper, ND, in 2005 and 2006. The experimental design was a randomized complete block with four replicates, with a split–plot arrangement, where the whole plot was a factorial arrangement (2 × 2) of two seeding dates, optimum and late, with or without soil packing after seeding. The subplot treatments were three seeding depths (surface, 13, and 25 mm). The same plot planter was used to adjust seeding depth to 13 and 25 mm. Each experimental unit had six rows 4.6-m long with a between-row spacing of 0.31 m. Traits evaluated were pure live seed emergence (PLSE), plant stand, plant height at harvest and seed yield. The main effect for seeding date did not have an effect on PLSE and resulted in adequate stands from both late May and mid June plantings averaged across environments. The seeding depth by soil packing interaction was significant for PLSE, plant stand and seed yield. Pure live seed emergence, plant stand, and seed yield were greater if the soil was packed compared with non-packed for the surface seeded treatment. The soil packing treatment did not influence PLSE, plant stand, or seed yield at the 13- and 25-mm seeding depths. Plant stands obtained from the non-packed surface and 13-mm seeding depths was adequate for high seed yield, as the plants branched to compensate for the lower plant density. Although surface seeding with packing produced satisfactory plant stands, reliance on timely rainfall is required for this to be successful. For this reason, the recommendation for seeding at the 13-mm depth without soil packing would ensure a better chance for sufficient soil water absorption by the seed to initiate germination. If surface seeding is practiced, a roller-packer to incorporate seeds and firm the seedbed after planting is recommended. 相似文献
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Astère Bararyenya Pierre-Claver Nahayo Anicet Nduwimana Pierre Niyonzima Déo Nyawakira Jean-Pierre Sindihebura Ernest Vyizigiro Vital Ndayishimiye Anton J. Haverkort 《Potato Research》2018,61(1):73-88
From 2014 through 2016, on-farm experiments were carried out in three provinces surrounding Bujumbura town in Burundi to improve the low potato (Solanum tuberosum) yields, which currently stand at about 6 t ha?1. It was hypothesised that in rain-fed conditions, improved varieties, healthier seed tubers, pre-sprouting in light, proper fertilisation and protection from late blight attack would improve yield and quality, such as tuber weight, tuber size and lower brown rot incidence. The treatments in the on-farm trials at five farms in each of three sites (15 replicates) were applied in two seasons, giving 30 replicates in 580 plots. The following treatments were compared with growers’ current practices: introduction of two new varieties, use of early generation seed from a rapid multiplication scheme, earlier harvesting of a seed crop, seed storage in a diffused light store, and research-based timing and dose rate of fertilisers and fungicides. Marginal rates of return on investments were calculated at farm level and current and tested alternative technologies were compared. Costs and benefits of applying such techniques were calculated. An improved variety contributed up to 20% yield increase and healthier seed 80%. Early harvesting reduced yield by 30% and reduced incidence of brown rot in the current season, but increased it (from 21 to 39%) in the following season when tubers were replanted. Diffused light storage, alternating contact and systemic fungicide application, and application of chemical fertilisers resulted in 30, 50 and 60% yield increases, respectively. It was shown that it is possible to double yields and economic returns (marginal rates of return) under the growing conditions in Burundi when growers plant healthy pre-sprouted seed of a new variety and apply chemical fertilisers and fungicides. 相似文献
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We examined the effects of cultivar (Taporuri, Mohretsu, Tachiaoba, and Hinohikari) on estimated total digestible nutrient (TDN) yield of forage rice in double harvesting. The total estimated whole-plant TDN yield (i.e., of the first crop plus second crop) of Taporuri was the highest in double harvesting. In the first crop, the estimated whole-plant TDN yield of Taporuri was the highest. In the second crop, the estimated whole-plant TDN yield of Taporuri was almost the same as those of Mohretsu and Tachiaoba but higher than that of Hinohikari. We also examined the effects of cultivation method (double harvesting or single harvesting) on estimated TDN yield of forage rice. In Taporuri and Mohretsu, the total estimated whole-plant TDN yield was similar in double harvesting and single harvesting. However, in Tachiaoba and Hinohikari, it was lower in double harvesting than in single harvesting. It is important to maximize the amount of nutrition in leaf and stem rather than panicle because the grain is not digested well by cattle. In the double harvesting, the total estimated leaf blade (leaf) TDN yield of Taporuri was higher than that of Hinohikari and almost the same as those of Tachiaoba and Mohretsu. The total estimated leaf sheath plus stem (stem) TDN yield of Taporuri was the highest. In comparison of the total TDN yield of double harvesting with that of single harvesting, the total estimated leaf and stem TDN yields were higher in double harvesting than in single harvesting in all cultivars except for Hinohikari. Thus, double harvesting of Taporuri is an effective way of reducing the overall loss of nutrition from the crop. 相似文献
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A survey, covering some 140 fields, totalling 1540 acres, in Kent was conducted in 1961 on the effect of different methods of management on yields of perennial ryegrass and white clover seed. The main results were: (a) the majority of seed growers harvested seed from short-term leys and only a limited acreage of permanent pasture was used for producing seed. Yields of both ryegrass and clover seed were considerably higher on the younger leys; (b) the highest seed yields in 1961 were obtained from fields where sheep grazing was stopped on 24 May. However, a large number of growers continued sheep grazing well after this date: (c) mechanical defoliation, especially when used to supplement sheep grazing, proved an effective method for producing high yields of clover seed; (d) honey bees are important in increasing seed yields, particularly on recently sown leys; (e) combine harvesting from the swath was the most common method of harvesting and no instance of the use of tripods was reported. Seed yields from baling methods were generally low, but direct combining produced a high average yield of clover seed. From these results it was concluded that there was much scope for raising the general level of clover seed yields, especially by giving greater attention to details of management. 相似文献
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Simulated long-term effects of different soil management regimes on the water balance in the Loess Plateau, China 总被引：1，自引：0，他引：1
Shulan Zhang Elisabeth Simelton Lars Lvdahl Harald Grip Deliang Chen 《Field Crops Research》2007,100(2-3):311-319
A soil management regime that improves water use efficiency (WUE) is urgently required to increase the sustainability of the winter wheat-summer fallow system in the Loess Plateau, China. However, the long-term partitioning of the water balance must be understood in order to evaluate the viability of possible soil management regimes. Therefore, an ecosystem model (CoupModel) was used to explore the effects on components of the water balance of five types of soil management regimes: conventional practice, wheat straw mulching, incorporation of high organic matter contents, compaction, and use of a harvested fallow crop. Three variants of the fallow crop approach were also considered, in which the crop was harvested 15, 30 and 45 days before sowing the wheat (designated Fallow-15d, Fallow-30d and Fallow-45d, respectively). Simulations were used to identify the relative magnitude of soil evaporation, wheat transpiration and deep percolation and to elucidate the temporal variability in these components for a selected location using climate records spanning 45 years. However, the soil management regime significantly influenced the magnitude of every component of the water balance (in terms of minimum, maximum and mean values) over the long periods considered. Consequently, wheat yield and WUE differed significantly among the simulated treatments. Mulching led to significantly lower soil evaporation, higher transpiration, and more frequent and extensive deep percolation than other regimes, thereby improving fallow efficiency (percentage of rainfall stored in the soil during the fallow period at the end of the fallow period), wheat yields and WUE. In contrast, soil compaction gave the opposite results, leading to the most unfavourable partitioning of the water balance reflected in the lowest wheat yield and WUE values of all the regimes. In 90% of the years no deep percolation occurred in the soil compaction simulations. Use of a fallow crop with optimal harvest timing (Fallow-30d) improved partitioning of the water balance (decreased soil evaporation) and did not significantly reduce wheat yield compared with conventional practice. High organic matter contents in the soil also had a positive influence on the water balance and improved wheat yield and WUE relative to conventional practice. Therefore, mulching appears to be the best management practice for the winter wheat-summer fallow system in the Loess Plateau, according to the simulations. Increasing soil organic matter may be the best option if mulching cannot be implemented. The ideal time for harvesting a fallow crop for use as green manure or fodder appears to be ca. 30 days before sowing the winter wheat. 相似文献
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Mohammad Nazir Farrukh H. Shah 《Plant foods for human nutrition (Dordrecht, Netherlands)》1985,35(1):51-56
Yields of green fodder, dry matter and nitrogen were adversely affected by an increase in the harvesting interval of Persian clover from 40 to 100 days. The optimum harvesting interval which gave maximum yield of green fodder (86.6 ton/ha) and dry matter (11.2 ton/ha) was 30 days. The maximum yield of total nitrogen (423 kg/ha) was obtained when the harvesting interval was 20 days. 相似文献
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China is one of the major rapeseed production countries in the world,but harvesting mechanization was still backward,and high harvest loss was a key inhibiting factor for rapeseed production.To obtain optimum harvesting date for winter rape in the Yangtze River Valley of China,artificial simulated combine harvesting and artificial two-stage harvesting were adopted to find correlations between harvesting date,rape variety,seed oil content,protein content,grain moisture rate,rapeseed straw moisture content,rapeseed unthreshing rate,grain drop loss rate,thousand seeds weight(TSW),and harvesting economic coefficient(HEC).Analysis of variance showed that rapeseed oil content,protein content and TSW were correlated with rape variety;HEC was correlated with harvesting method and rape variety.Rape variety was the dominant factor of rapeseed oil content,protein content,TSW and HEC.Grain moisture rate,un-threshing rate,grain drop loss rate and straw moisture content were correlated with harvesting method and date.Harvesting date was the dominant factor of rapeseed moisture rate,un-threshing rate,grain drop loss rate and straw moisture rate.Single factor tests further proved that harvesting date had less impact on rapeseed oil content,protein content,TSW and HEC.It showed little correlation with rapeseed quality except grain moisture rate.The optimum harvesting date could be known by change in straw moisture content.The combined harvesting should be carried out during the grain moisture content of 15%-20%with TSW stabilized in the highest level.The twostage harvesting cutting should be carried out at the grain moisture content of 35%-40%.This research offered a reference to harvesting method and date for rape cultivated in the Yangtze River Valley. 相似文献
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An experiment is described in which 32 plots of S24 ryegrass were harvested by two methods, direct- and swath-harvesting at four cutting dates over a period of 14 days. The difference between the two methods was marginal but highest yields and quality were obtained by cutting when seed moisture content was between 53 and 40% and harvesting from the swath when it was about 30%, By the time the seed in the uncut crop had reached 30% moisture, yield from direct harvesting was greater than that from cutting followed by swath-harvesting, although the yields from both methods were falling. The practical significance of these results is discussed. 相似文献
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Cruciferous catch crops are an important source of forage, particularly in sheep systems, but due to their late sowing date, commonly July or early August, soil moisture is often a limiting factor in crop establishment and subsequent growth, causing wide variations in yield from year to year. Crops of stubble turnip ( Brassica campestris ssp. rapifera ), forage rape ( B. napus ssp. biennis ) and fodder radish ( Raphanus sativus ) were grown at Hurley between 1969 and 1977. Fodder radish was the most variable in dry matter (DM) yield, while stubble turnip was the most stable. Both DM yields and in vitro digestibilities rose during the autumn, reaching a maximum in mid-December for stubble turnip and forage rape, and in mid to late November for fodder radish. Yield and digestibility subsequently declined. The N concentrations of the forages exhibited a contrary trend, reaching minimum values at about the time of the highest DM yields. The gradual changes in crop quality suggest that the crops are well suited to grazing utilization, in which management is simplified if crop quality shows little variation. 相似文献
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Tertyllianos MitsisAspasia Efthimiadou Dimitrios J. Bilalis Nicholas G. DanalatosPanagiotis Efthimiadis Aristidis Konstantas 《Industrial Crops and Products》2011,33(2):544-548
Adverse hot and dry environmental conditions prevailing during the period of oilseed rape ripening can be blamed for considerable yield losses during the crop's mechanized harvesting in the Mediterranean area. In this paper, the effect of chemical dessication of oilseed rape with glyphosate applied 35 days after anthesis for reducing seed yield loss was studied. The experiment was conducted in four fields at two locations in central Greece and for two growth periods following a completely randomized plot design with 8 treatments in three replications. Treatments include all possible combinations of two crop varieties and four levels of glyphosate (as dessicant) application. A significant positive effect of dessicant application level on crop yield for both studied varieties was found. The application dose of 200 g a.i. of glyphosate per hectare had the best results. The highest dry weight was found among the plants sprayed with 200 g. a.i. of glyphosate per hectare. The highest seed yield and oil yield were found among the plants sprayed with 200 g a.i. per hectare, which makes clear the positive effect of this spraying minimizing pod shattering and yield losses. The greatest 1000-seed weight was found among the plants sprayed with 200 g a.i. ha−1, due to the greater size of seeds that remained on the plants until harvesting. 相似文献
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兴垦3号是内蒙古丰垦种业有限责任公司选育的粮饲兼用型玉米品种,在多年生产示范试验中籽粒平均产量8897.3～12505.5kg/hm2,比对照种增产6.0%～21.4%,最高产量可达13036.7kg/hm2。该品种淀粉含量高,籽粒脱水快,抗倒伏、耐密植、抗瘤黑粉病、茎腐病和丝黑穗病,活秆成熟,可粮饲兼用,在东北地区有极好的利用价值和广阔的开发前景。 相似文献