旱地玉米免耕整秸秆覆盖田化学除草试验

在１９９０年和１９９２年田间试验基础上，提出了旱地玉米免耕整秸秆覆盖田适用的、经济有效的化学除草技术，除草效果达９８％以上，比人工除草提高９个百分点，每亩除草成本降低７．７～９．３元，除草经济效益提高４６．５％～４８．１％。     

阴山北麓保护性耕作油菜田间杂草控制试验

据调查,阴山北麓保护性耕作油菜田初期杂草密度增加,田间杂草发生时间提前,上下茬农田杂草重叠发生,多年生杂草为害加重。采用化学除草、机械除草、人工除草、农业轮作等单因素和多因素除草技术进行研究。结果表明,采用综合除草"深松+高特克+胺苯磺隆+龙拳"和"中耕+高特克+胺苯磺隆+龙拳"除草效果好,杂草株防除率和鲜质量防除率均达90%以上。     

Soil seed banks are short-lived and triggered by the first effective rainfalls in the vacant lots of Santiago,Chile

We studied the temporal variation of the soil seed banks in the urban lots of Santiago, Chile. As most of the plants that emerge from the seed banks in lots are also found in open habitats and are easily germinable, we hypothesize that the seed banks in lots are highly dynamic and short-lived, with the bank depleted every year during the germination season to be reloaded with new seeds during the next seed dispersal period. In each 20 lots for two year (2017 and 2018), 9 soil samples were collected. These samples were obtained from three sampling points randomly distributed across the plots. The seed bank was estimated by seed germination in soil samples placed in plastic trays. The samples of all the lots were stratified at 2 °C by 3 months before sowing. In order to record the seed persistence, soil of three lots watered in 2017 for six months were dried and maintained under dark and non-watered conditions until re-sowing in autumn 2018. To determine if the seeds present cold-associated germination triggers, soils of five lots were maintained under dark conditions for 3 months (soils without cold stratification) for comparison with soils with cold stratification of the same lots. The above-ground plants were recorded in all lots for both years. Forty plant species were recorded in soil bank. The total emerged seedling densities ranged between 7,944 (2017) to 3,700 seedlings m^-2 (2018). Species per lot varied between 17 and 7 during 2017, and between 14 and 3 during 2018. In five lots, seedling densities were not statistically different between cold stratified soil at 2 ° C and non-stratified. In three lots with re-sown soil, seedling density of the first sowing (4,096 seedlings m^-2) was significantly higher than second sowing (201 seedlings m^-2). Thirty-seven plant species were recorded in the above-ground vegetation during 2017 and 42 species in 2018. Species frequency of the seed bank was positively correlated with species frequency of above-ground vegetation. Concluding, the bank is highly dynamic, short-lived, and is depleted every year during the germination season, which begins with effective rainfalls, would be reloaded with seeds during the seed dispersal period.     

Assessment of management options for Chilean needle grass in sheep‐grazing systems

Chilean needle grass [Nassella neesiana (Trin. & Rupr.) Barkworth; CNG] is a perennial spear grass that has invaded pastures in south‐eastern Australia and can lead to a substantial reduction of stockcarrying capacity during the summer months. This study examined a range of grazing, herbicide and pasture resowing options, alone or in combination, on CNG and introduced pasture grass basal cover, for several CNG‐infested sites in south‐eastern Australia. At each site, options were chosen on the basis that they were most likely to control the CNG infestation while maintaining a productive sheep‐grazing enterprise on grass pastures. After 2 years of management, the reduction in CNG basal cover in set stock plots that were sprayed with flupropanate, versus those not sprayed, ranged from non‐detectable to a reduction of 80%, depending on site location. After 5 years of management, the reduction ranged from zero to 50%. Grazing management or sowing of competitive pastures did not generally reduce CNG basal cover to low levels. None of the management options maintained reasonable levels of desirable perennial species by the end of 4–5 years. We conclude that, because of the persistence of CNG, the need for regular spraying of herbicide, and the relative ineffectiveness of other control methods, management systems may need to be developed that utilize CNG while minimizing its input to the soil seedbank.     

Influence of nitrogen and weed management on the productivity of upland rice

Nitrogen and weeds are two important factors that influence the productivity of rainfed upland rice (Oryza sativa L.) in tropical Asia. A low recovery of applied fertilizer N in rainfed uplands is generally associated with high nitrate leaching losses and weed interferences. Field experiments were conducted during the wet seasons of 2002 and 2003 at the research farm of Central Rainfed Upland Rice Research Station, Hazaribag, Jharkhand, India, to determine the response of upland rice to nitrogen applied at 60 kg N ha^–1 as different forms of urea (single pre‐plant application of controlled‐release urea, single pre‐plant application of urea supergranules, and split application of prilled urea with or without basal N) against no N application under three weed‐control regimes (unweeded, pre‐emergence application of butachlor at 1.5 kg a.i. ha^–1 supplemented with one single hand weeding or two hand weedings). The response of rice to applied N varied greatly among the three weed‐control regimes. Across the different N treatments, the application of 60 kg N ha^–1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha^–1 in unweeded treatments, whereas yields increased by 1.07 Mg ha^–1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha^–1 with two hand weedings. Among the weed‐control measures, hand weeding twice produced highest grain yield in both years. The comparison of different forms of urea showed that a single pre‐plant application of controlled‐release urea resulted in average grain yields of 1.57 and 1.87 Mg ha^–1 compared to 1.32 and 1.30 Mg ha^–1 in the case of the recommended practice of split‐applied prilled urea in the years 2002 and 2003, respectively. The highest agronomic N use efficiency of 15–20 kg grain per kg N applied and the highest apparent N recovery of 39%–45% were attained with controlled‐release urea, suggesting that this N form is particularly beneficial for upland‐rice cultivation under variable rainfall conditions, provided weeds are controlled.     

除草剂混用苗期茎叶喷雾防除胡麻田杂草与大面积应用示范

为达到一次使用除草剂兼防胡麻田阔叶杂草与禾本科杂草,笔者开展了2甲·辛酰溴等3种新型阔叶杂草除草剂与高效氟吡甲禾灵等7种禾本科杂草除草剂混用苗期茎叶喷雾防除胡麻田杂草试验。结果表明:40%2甲·辛酰溴EC 1500 mL/hm2或30%辛酰溴苯腈EC 1500 mL/hm2与108 g/L高效氟吡甲禾灵EC 1500 mL/hm2等7种禾本科杂草除草剂混用对胡麻田阔叶杂草均具优良防效,株防效和鲜重防效在94.17%~98.71%之间。40%2甲·辛酰溴EC 1500 mL/hm2或30%辛酰溴苯腈EC 1500 mL/hm2、80%溴苯腈SP 600 g/hm2与108g/L高效氟吡甲禾灵EC 1500 mL/hm2或10%精喹禾灵EC 900 mL/hm2、50 g/L唑啉草酯EC 1350 mL/hm2、15%炔草酯WP 750 g/hm2混用对胡麻田禾本科杂草均具优良防效,株防效和鲜重防效在97.22%~100%之间。从安全性、兼防效果、用药成本和增产效果综合评价,40%2甲·辛酰溴EC 1500 mL/hm2或30%辛酰溴苯腈EC 1500 mL/hm2+108 g/L高效氟吡甲禾灵EC 1500 mL/hm2或10%精喹禾灵EC 900 mL/hm2是苗期茎叶喷雾一次用药兼防胡麻田阔叶杂草与禾本科杂草的最佳组合,宜在胡麻生产中大面积推广应用。     

冬油菜田杂草探测光谱传感器设计与应用

杂草的精确识别是对靶施药和自动化机械除草的关键前提,基于光谱分析技术的光谱传感器可以实现快速、无损的杂草识别.该文以冬油菜苗期杂草为研究对象,根据试验选取的4个特征波长点(595、710、755和950 nm),设计了一种能自动识别杂草的光谱传感器.根据光学系统原理和田间实际操作要求,提出了该光谱传感器的结构设计方案,选择了合适的光学器件,并开发了光谱传感器信号调理电路.对光谱传感器进行了标定和试验验证,根据便携式光谱仪和光谱传感器在4个波长下的测量结果建立了相应的标定方程,方程的决定系数分别为0.799、0.812、0.892和0.867,验证试验结果的相对误差绝大多数都在10％以内,可以识别冬油菜苗期田间杂草.该传感器为杂草自动探测装置的开发提供了参考.     

淮北市夏玉米病虫草害发生新特点及防治对策

分析了当前玉米病虫草害发生的新特点、新变化以及主要原因,同时指出了当前夏玉米病虫草害防治中存在的主要问题,并提出了选用优质高抗品种、合理布局作物的种植、加强预测预报、强化统防统治与绿色防控、对售药及施药人员加强专业培训、推广安全科学施药技术等一系列防治对策。     

围栏措施对青藏高原高寒草甸群落结构和稳定性的影响

人工条件下高寒脆弱生态系统群落结构及其稳定性的变化是研究其生态功能的重要内容。本研究以乌玛塘高寒草甸示范区为例,对研究区植被进行植物群落学调查,对植物群落功能群和稳定性进行分析,研究了高寒草甸植物群落在围栏4年和8年后,围栏内外群落的结构变化和稳定性差异。结果表明,1)围栏内物种多样性大于围栏外;围栏4年后群落内一年生、二年生植物重要值明显高于围栏外;围栏8年后,群落优势种发生变化,高山嵩草(Kobresia pygmaea)优势度降低,一年生、二年生植物甘肃马先蒿(Pedicularis kansuensis)成为优势物种之一;多年生禾草,杂类草以及一年生、二年生植物3个功能群所含物种数显著多于围栏外(P0.05);2)围栏4年后群落稳定性表现为围栏内围栏外,8年后表现为围栏内围栏外。短期围栏使得群落稳定性高于未围栏的群落,但是群落结构差异并不明显,随着围栏时间增加,群落结构发生明显变化,且群落稳定性降低,围栏外群落则趋向于稳定。     

山羊草属检疫性杂草PCR-RFLP鉴定方法的研究

禾本科山羊草属具有多种农田杂草,其中具节山羊草和节节麦是我国禁止进境的检疫性杂草,我国检验检疫部门在进口粮谷检疫中经常会截获具节山羊草和节节麦。由于检疫性山羊草属杂草在植株及种子形态上与其近似种不容易区分,给检疫鉴定带来了很大困难。本文研究了一种PCR-RFLP分子鉴定方法,能够快速、准确地将检疫性山羊草属杂草与非检疫性种类区分开来,解决了该类杂草鉴定难题。