灌水对冬小麦耗水量和产量影响的试验研究

2006年10月~2008年5月在山西省运城灌溉试验站进行了两年的冬小麦需水量和灌溉制度试验研究。结果表明,冬小麦的耗水规律为播种~越冬阶段0.48~1.11 mm/d;越冬~返青阶段0.14~1.07 mm/d;返青~拔节阶段0.69~2.10 mm/d;拔节~抽穗阶段2.02~4.27 mm/d;抽穗~灌浆阶段达到最大值3.57~8.62 mm/d;灌浆~收获阶段1.63~3.85 mm/d。冬小麦耗水量与产量呈抛物线关系,为了取得高产和较高的水分利用率,全生育期的耗水量应在380~440 mm之间。在当地气候、土壤及栽培模式下,冬小麦的灌溉制度为全生育期灌水3次,灌水定额60~80 mm,灌溉定额180~240 mm。     

不同灌水量对菊芋生长及水分利用效率的影响

在不同灌水处理下菊芋株高、茎粗和单株个数的差异不显著,株高生长期主要在枝繁叶茂期和现蕾期,而茎粗生长期在苗期和枝繁叶茂期;菊芋产量、单株产量及水分利用效率均存在显著性差异,产量和单株产量以J6处理(耗水量最大)最高,J6处理的产量分别比J1、J2、J3、J4、J5处理提高56.52%、28.68%、46.21%、37.75%、8.97%,J6处理的单株产量分别比J1、J2、J3、J4、J5处理提高65.45%、26.39%、27.27%、28.17%、31.88%,水分利用效率则以J1处理(耗水量最小)最高,分别比J2、J3、J4、J5、J6处理提高15.98%、50.67%、85.96%、58.68%、79.16%。试验条件下菊芋产量主要由单株产量决定,并随耗水量的增加呈增加趋势,而水分利用效率则呈下降趋势。菊芋最佳灌溉定额为340 mm左右。     

Maximum economic yield in crisis?

We examine the claim in Christensen that Maximum Economic Yield (MEY) is equal to Maximum Sustainable Yield (MSY). The basis for this claim is that MEY considers only the ‘catching’ of fish and that when the full value‐chain is considered; it is the MSY level that maximizes economic value. We argue that to maximize society’s benefit from a given sector of an economy, resources need to be allocated across all sectors such that additional net benefits from employing one more unit of society’s resources are equalized across all sectors of the economy. In this way, the opportunity cost of employing society’s resources across all economic sectors is minimized. In an economy where all resources are fully utilized, further value added in the value chain for fish is an additional cost and has the effect of reducing fishing effort and optimum yield rather than the opposite. In a less developed economy or a developed one in recession where all resources are not fully used, the multiplier effect could be important, and if it is high for fisheries it would be an argument to maximize sustainable yield and effort. We show, using current input‐output data, that this is not the case. Furthermore, from a simple principle of optimization, we know that to optimize a sector that consists of many segments through time, one has to optimize every portion of the chain through time.     

杉木采穗圃的营建及管理技术研究

通过试验研究杉木采穗圃母株不同定植株行距、母株距根茎处不同截干促萌高度及圃地施用不同种类的基肥对母株产穗量的影响,结果表明:杉木母株定植株行距20 cm×20 cm+母株距根茎部位15 cm处截干+施用1 050 kg.hm-2硫酸钾复合肥作基肥(A3B3C2)组合产穗量最高,母株嫩枝单株年平均产穗量18.8穗,母株硬枝单株年平均产穗量15.9穗。     

钾肥施用分配比例对甘蔗生长的影响

以甘蔗品种粤糖00-236为试材,通过盆栽试验,研究了在滴灌施肥条件下钾肥施用分配比例对甘蔗产量和品质的影响。结果表明,在总施钾量相等时,甘蔗不同生长期钾肥分配比例的不同对甘蔗伸长速度、蔗茎产量、干叶重的影响均表现为差异不显著;钾肥施用量不同分配比例中,22.5%~55%~22.5%、30%~50%~20%、20%~60%~20%1、0%~60%~30%四种钾肥分配方式更有利于提高甘蔗蔗糖分、蔗汁蔗糖分和蔗汁锤度。因此,在甘蔗水肥管理中,应注重中、后期的钾素供应,以利于甘蔗糖分的积累和品质的提高。     

不同栽植密度对脱毒红薯产量及经济效益的影响

为确定三康8号脱毒红薯的最佳栽植密度并为其推广应用提供依据,采用大田试验方法,研究了不同栽植密度对脱毒红薯产量和经济效益的影响。结果表明:栽植密度为4 600株/667m2时,鲜薯产量高达2 577.9 kg/667m2,产投比高达2.37,是三康8号脱毒红薯的最佳栽植密度。     

Foliar Application of Glycinebetaine and Salicylic Acid Improves Growth,Yield and Water Productivity of Hybrid Sunflower Planted by Different Sowing Methods

Improved planting methods and foliar application of glycinebetaine (GB) and salicylic acid (SA) can improve the water productivity in field crops under limited water supply conditions. A 2‐year field study was conducted to evaluate the possible role of different planting methods and foliar applications of GB and SA in improving the yield, quality and water productivity of hybrid sunflower (Helianthus annuus L.). The crop was planted by flat sowing (75 cm spaced rows) and ridge sowing (75 cm spaced ridges), with GB and SA applied exogenously at 100 and 0.724 mm , respectively, at both budding and flowering stages, while control plots received distilled water. Ridge sowing, rather than flat sowing, improved the biological yield, oil yield, leaf area index (LAI), crop growth rate (CGR), plant height, water‐use efficiency and final achene yield during both the years. Foliar applications of GB and SA at both the stages improved the achene yield, although foliar application of GB at flowering was the most effective. Neither the planting methods nor the foliar application of GB and SA altered the achene oil contents during both the years. Foliar application of GB and SA increased the free proline content of the leaf and GB contents at flowering but reduced the achene protein contents, whereas planting method had no effect on these attributes across the years. Of the foliar applied chemicals, GB was more effective in improving sunflower growth and yield and water productivity than SA. To conclude, ridge sowing coupled with foliar application of GB at flowering stage could be beneficial for achieving maximum yields of hybrid sunflower under relatively water limited conditions in the field.     

Relationship Between Heterosis and Parental Genetic Distance Based on Molecular Markers for Functional Genes Related to Yield Traits in Rice

The genetic distances among 18 cytoplasmic male sterile lines and 11 restorer lines were analyzed with molecular markers derived from yield-related functional genes.The correlation between parental genetic distance and heterosis was investigated by analyzing the performance of 47 combinations.The results showed that the genetic distance was significantly correlated with yield heterosis(r=0.29*),but not significantly correlated with heterosis for other traits,such as number of effective panicles per plant,se...     

不同氮肥用量对水稻黄华占产量及主要经济性状的影响

为充分发挥水稻黄华占高产高效潜力,本试验研究了不同氮肥用量对黄华占产量及产量构成因素的影响,结果表明:黄华占纯氮用量以180kg/hm2为宜,在土壤肥力水平较高地区种植,纯氮用量应酌减,但一般不宜低于150kg/hm2,且经济效益较高。     

Deficit irrigation and nitrogen effects on seed cotton yield, water productivity and yield response factor in shallow soils of semi-arid environment

A field experiment was conducted for 2 years to investigate the effects of deficit irrigation, nitrogen and plant growth minerals on seed cotton yield, water productivity and yield response factor. The treatment comprises six levels of deficit irrigation (Etc 1.0, 0.9, 0.8, 0.7, 0.6 and 0.5) and four levels of nitrogen (80, 120, 160 and 200 kg N ha⁻¹). These were treatments superimposed with and without plant growth mineral spray. Furrow irrigation treatments were also kept. Cotton variety Ankur-651 Bt was grown during 2006 and 2007 cotton season. Drip irrigation at 1.0 Etc saved 26.9% water and produced 43.1% higher seed cotton yield over conventional furrow irrigation (1.0 Etc). Imposing irrigation deficit of 0.8 Etc caused significant reduction in seed cotton yield to the tune of 9.3% of the maximum yield. Further increase in deficit irrigation from 0.7 Etc to 0.5 Etc significantly decreased seed cotton yield over its subsequent higher irrigation level. Decline in the yield under deficit irrigation was associated with reduction in number of bolls plant⁻¹ and boll weight. Nitrogen at 200 kg ha⁻¹ significantly increased mean seed cotton yield by 36.3% over 80 kg N ha⁻¹. Seed cotton yield tended to increase linearly up to 200 kg N ha⁻¹ with drip Etc 0.8 to drip Etc 1.0. With drip Etc 0.6-0.5, N up to 160 kg ha⁻¹ provided the highest yield, thereafter it had declined. Foliar spray of plant growth mineral (PGM) brought about significant improvement in seed cotton yield by 14.1% over control. The water productivity ranged from 0.331 to 0.491 kg m⁻³ at different irrigation and N levels. On pooled basis, crop yield response factor of 0.87 was calculated at 20% irrigation deficit.