Applying acoustic emission and neural network to classify wheat seeds from weed seeds

In the present study,an expert weed seeds recognition system combining acoustic emissions analysis,Multilayer Feedforward Neural Network(MFNN)classifier was developed and tested for classifying wheat seeds.This experiment was performed for classifying two major important wheat varieties from five species of weed seeds.In order to produce sound signals,a 60o inclined glass plate was used.Fast Fourier Transform(FFT),Phase and Power Spectral Density(PSD)of impact signals were calculated.All features of sound signals are computed via a 1024-point FFT.After feature generation,60%of data sets were used for training,20%for validation,and remaining samples were selected for testing.The optimized MFNN model was found to have 500-12-2 and 500-10-2 architectures for“101”and“Shiroodi”wheat varieties,respectively.The selection of the optimal model was based on the evaluation of mean square error(MSE)and correct separation rate(CSR).The CSR percentages for two wheat varieties were 100%.Considering the overall aspects of the results,it can be stated that the developed system was successful enough to correlate the acoustic features with wheat seed type.

Influence of long-term different fertilization on soil weed seed bank diversity of a paddy soil under rice/rape rotation

A long-term fertilized paddy field under rice/rape rotation in the Taihu Lake Region was selected to investigate the dynamics of soil weed seed diversity.Four fertilizer treatments were performed,including non-fertilizer(NF),chemical fertilizer only(CF),chemical fertilizer combined with pig manure(CMF)and chemical fertilizer plus crop stalk(CSF).We recorded the seed numbers and crop yields,estimated the weed seed bank density and identified the kinds of weed seeds in the top-soil(0-15 cm)in the study area using a stereomicroscope.Based on the records,we analyzed the effect of long-term fertilization on soil weed seed bank diversity and the rela-tionship between weed seed diversity and crop yields.Comparing the four treatments,it was found that in the cultivating seasons of both rice and rape,the density of soil weed seed bank was the lowest with the treatment of chemical fertilizer plus crop stalk.Whereas,the total number of species and the weed seed bank diversity was the highest.Furthermore,the crop yields were at maximum and kept constant with this treatment.There was a definite correlation between fertilizer treatment and soil weed seed bank diversity and crop yields.It was concluded that balancing the fertilizer management was helpful in main-taining soil weed seed bank diversity,increasing crop yields and alleviating crop yield fluctuation.Therefore,among the four fertilizer treatments,chemical fertilizer plus rice crop stalk treatment was the best one to stimulate the productivity of agricultural ecosystems and simulta-neously protect biodiversity.

Enhanced Species Diversity Unlocked by Habitat Conservation in Agricultural Landscapes: New Perspectives on Ecological Weed Management and Sustainable Intensification—Species Diversity and Habitat Conservation

The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current literature, reporting specifically on the impact of production intensification on habitats and yield constraints caused by weeds. Secondly, in alleviating these effects over the short term, ecological measures that enhance species diversity in conserved habitats and promote semi-natural habitats in the agricultural landscape, are discussed. In large-scale intensive agriculture, weed control is predominantly rooted in agrochemical applications in the form of herbicides. Long lasting intensive agricultural practices show discord both with the promotion of the biodiversity of microbes belowground and aboveground and with organisms involved in the breaking down of plant material. The presence of native species in the surroundings, in combination with hedgerows and field margins, with a comparatively intricate and balanced variety of plants in a sheltered environment, are essential for settlement of benign insects, particularly in the face of intensive agricultural production. The promising tactic of advantageous seed predators enables decreased herbicide applications. Crop mosaics arranged to advance compatibility at the landscape scale are important to bolster pollination services and insect management, while ecological variety in the surroundings acts as a safety net for habitat diversity. Weed control in combination with different tactics of vegetation use, comprising cover cropping, hedgerows and field margins, sets up safe havens in the landscape, and improves the diffusion of complementary life forms. Field margins perform a meaningful natural function as point of provision for forage, safe havens and distribution passageways for pollinators and insect predators. Production practices that promote more heterogeneity and combine high density semi-natural safe havens and habitat conservation in agro ecosystems are beneficial to species diversity across trophic levels and contribute to agricultural production stability and food safety.

Evaluation of Weed Control Efficacy and Seed Cotton Yield in Glyphosate Tolerant Transgenic Cotton

Cotton is one of the important crops that have been genetically altered to address challenges with weed and insect control. The research was conducted with glyphosate resistant cotton hybrids during winter irrigated season of 2009-10 and 2010-11 at the experimental site of Tamil Nadu Agricultural University, Coimbatore, with the objective, to find out the weed control efficacy and yield of transgenic cotton hybrid with the application of glyphosate. Glyphosate was applied as post-emergence application on 25 and 65 DAS at 900, 1350, 1800, 2700, 3600 and 5400 g a.e./ha in MRC 7347 BG-II RRF test hybrid. These treatments were compared with hand weeding on 15 and 30 DAS and unweeded control. In both sprays, post-emergence application of glyphosate 2700, 3600 and 5400 g a.e./ha registered lower weed density and higher weed control efficiency in transgenic cotton hybrid compared with other treatments. Seed cotton yield (3195 and 3092 kg·ha-1 during 2009-10 and 2010-11 respectively) was significantly higher in post-emergence application of glyphosate at 2700 g a.e./ha. Increased use of transgenic cotton with herbicide and pest resistance has resulted in more efficient insect and weed management practices.

Chemical Weeding in Dry Direct Seeding Fields of Single Cropping Middlelate Rice

Chemical weeding in dry direct seeding fields of single cropping middle-late rice was studied in Huida vegetable farm of Huizhou City in 2012. The main treatment was herbicide（ pretilachlor ＋ bensulfuron-methyl,Yangguo and butachlor）,and the sub-treatment was application method（ soil treatments,seedling treatment and integrated treatment）. The results showed that 80 g pretilachlor ＋ bensulfuron-methyl（ 36% pretilachlor ＋ 4% bensulfuron-methyl） diluted with 50 kg water could be sprayed or 200 g Yangguo（ 23. 9% butachlor ＋ 1. 1% bensulfuron-methyl） mixed with 15 kg sandy soil could be broadcasted per 667 m2 on the sowing day or the second day under moist condition of soil,which could effectively control weeds in dry direct seeding fields of single cropping middle-late rice.

Environmental Factors Influencing Seed Germination Characteristics of Vicious Weed Green Foxtail

[ Objective] The paper was to optimize the optimal conditions for seed germination and seedling emergence of green foxtail [ Setar/a viridis （ L. ） Beauv. ], so as to solve the problem of serious damage caused by green foxtail. [Method] Using the orthogenal test and the LSD method of software SPSS 18.0, with the number of emerged seedlings of green foxtail as the evaluation index, the influencing factors such as pretreatment of green foxtail, earth covering depth, soil temperature and soil moisture content were compared in the test. [Result] These four experimental factors had great impact on seed germination characteristics of green foxtail. The optimal scheme for seedling emergence of green foxtail was as follows： pretreatment of green foxtail for 3 d, earth covering depth 0.5 cm, soil temperature 32 ℃, soil moisture content 15%. The optimum condition was consistent with the actual situation of serious damage of green foxtail （ suffering moderate and heavy rainfall after sowing and before seedling of millet ）. Avoiding sowing millet before moderate and heavy rainfall could effectively control serious damage of green fox＇tail. [ Conclusion] The study provided theoretical support for effective control against the vicious weed green foxtail.

Effects of Methane Fermentation on Seed Survival of Broad-Leaved Dock （Rumexobtusifolius L.） with Dairy Manure

To clarify the effect of exposure to methane fermentation on the survival of seeds of Rumexobtusifolius L. contained in dairy slurry, the percentage of seed germination was observed after the mesophilic （35 ℃） and thermophilic （55 ℃） methane fermentation. The number of survival seed was 0% at 55 ℃, 81.6% at 35 ℃ from methane fermentation, and 0% at 55℃, 75.5% at 35 ℃ after heat treatment. The survival rate of the seeds in methane fermentation was similar to heat treatment at 35 ℃. However, in the investigation of seed status, the number of primary and secondary dormant seeds was higher than after heat treatment. This result suggests that since Rumexobtusifolius L. seeds survive in dormant state in mesophilic methane fermentation, the usage of manure as fertilizer need to be considered.

Al elopathic Effects of Melilotus officinalis Desr. against Weeds

In this study, the allelopathic effects of 100 g/L water extract of Melilotus offtcinalis Desr. on seed germination and seedling growth of Melilotus offwinalis Desr., Trifolium pretense L. , Medicago sativa L. cv. Victoria, Echinochloa crusgalli （ L. ） Beauv., Lxer/s chinensis （ Thunb. ） Nakai and Plantago asiatica L. were investigated by biological assay. Dried powder of Melilotus officinalis Desr. was applied to the field in spring and winter to verify the inhibitory effects of Me- lilotus officinalis Desr. on weed biomass in the experimental field and compare the effects between Melilotus offwinalis Desr. and a variety of commonly used chemi- cal herbicides on weed suppression. The results showed that water extract of Melilotm officinalis Desr. posed significant effects on seed germination and seedling growth of Trifolium pretense L. , Echinochloa crusgalli （ L. ） Beauv. , Lxeris chinensis （ Thunb. ） Nakm, Plantago asiatica L. , Melilotus o^tcinalis Desr. and Medi- cago sativa L. cv. Victoria, exhibiting strong allelopathic effects, but the inhibition rate varied greatly among different plant species. Therefore, the allelopathic effects of Melilotus o^winalis Desr. should be utilized appropriately in practical applieatians. Dried powder of Melilotus officinalis Desr. significantly reduced weed quantity in the field for a short duration, which should be administered multiple times in a sufficient amount for weed control in the production.

Pre-emergence herbicides affect seedling emergence of tropical forest tree species

Testing techniques to reduce weed infestation is a crucial step in developing direct tree seeding systems. The use of pre-emergence herbicides may be an alternative to manual weeding techniques, but so far, information on how they affect the seeds of native tree species is scarce. We established a greenhouse experiment to evaluate the effects of four pre-emergence herbicides (atrazine, diuron, isoxaflutole and oxyfluorfen) on weed suppression and seedling emergence and early growth of seven tropical forest tree species (Annona coriacea Mart., Citharexylum myrianthum Cham., Cordia ecalyculata Vell., Peltophorum dubium (Spreng.) Taub., Psidium guajava L., Pterogyne nitens Tul. and Schinus terebinthifolia Raddi). The experimental design was a randomized complete block design with five treatments and five replicates. The treatments consisted of a single dose of each pre-emergence herbicide and a control. Throughout the 60 days after sowing we evaluated weed cover and seedling emergence and early growth of tree species. Overall, our results suggest that all tested herbicides reduced weed cover; however, they also negatively affected tree species seedling emergence. Of the four herbicides tested, atrazine and diuron showed the greatest effects on tree seedling emergence, oxyfluorfen was least aggressive towards native species and isoxaflutole was most effective in weed control. Native tree species varied in their responses to herbicides, indicating that future experiments should increase the number of species tested as well as investigate how seed traits can affect the species responses to different herbicides.

Effect of Establishment Methods and Weed Management Practices on Some Growth Attributes of Rice

Studies were carried out for two years to evaluate the effect of methods of sowing and weed control practices on the productivity of transplanted and direct wet-seeded rice in Dera Ismail Khan, NWFP, Pakistan. The experiment was laid out in a randomized complete block design with a split plot arrangement. The planting techniques viz. transplanting and direct seeding were maintained in main plots while weed control practices included the use of granular herbicide Sunstar 15WG （ethoxy sulfuron）, Machete 60EC （butachlor）, conventional hand weeding, and the weedy check （control） were assigned to the sub-plots. Data were recorded on weed parameters like weed density and dry weed biomass 60 and 90 days after sowing （DAS）; agronomic parameters including plant population, number of panicles and paddy yield and physiological parameters like leaf area index and net assimilation rate 45 and 90 DAS. The planting methods and weed management significantly influenced most of the parameters studied. The data revealed that the paddy yield and its components were significantly higher in the transplanted method than that in direct-seeded method, while the weed density and biomass were lower in the transplanted plots than the direct-seeded plots. Among weed management tools, the maximum paddy yield was obtained in hand weeding, closely followed by herbicide application Machete 60EC during both cropping seasons.

Impact of Tillage and Herbicides on Weed Density, Yield and Quality of Cotton in Wheat Based Cropping System

Conservation tillage may improve yield of cotton in addition to improvement in soil quality if practiced for longer period. However, the practice may not be productive in short-term particularly when severe weeds are infesting the crops such as Cynodon dactylon, Conyza canadensis, Tribulus terrestris, and Cyperus rotundus, etc. Recent studies indicate that conventional tillage （CT） is more productive than zero tillage （ZT）/reduced tillage （RT）. Performance of cotton under three tillage systems, viz., ZT, RT and CT; and five herbicides, i.e., haloxyfop-R-methyl 10.8 EC （108 g a.i. ha^-1）, lactofen 24 EC （168 g a.i. ha^-1）, haloxyfop 10.8 EC ＋ lactofen 24 EC, hand weeding, and weedy check were evaluated during 2010-2011 at Gomal University, D.I.Khan, Pakistan, to explore the best management option for effective weed control, enhanced yield and quality of cotton grown after wheat. The results revealed that hand weeding and Haloxyfop as post emergence alone or in combination with Lactofen reduced weed density to the minimum irrespective of the tillage systems. Excessive rainfall and cooler temperature limited cotton growth and yield in 2010. The adverse weather conditions had more adverse effect on boll weight under ZT and RT than CT. Haloxyfop ＋ lactofen produced higher seed cotton yield in RT than ZT, however, it could not exceed CT. Broad-spectrum herbicides x CT produced the highest number of bolls/plant, boll weight and seed cotton yield. Fiber quality and net returns were also the highest in broad-spectrum herbicides x CT. In conclusion, broad-spectrum herbicides under CT were more productive in wheat based cropping system on silty clay soil of D.I.Khan.

Weed Management in White Beans with Soil-Applied Grass Herbicides plus Halosulfuron

There are a limited number of soil-applied herbicides available for broad-spectrum weed control in dry bean production in Ontario, Canada. Four experiments were conducted from 2017 to 2019 in southwestern Ontario to compare the efficacy of six soil-applied grass herbicides [trifluralin (600 g ai ha-1), ethalfluralin (810 g ai ha-1), pendimethalin (1080 g ai ha-1), S-metolachlor (1050 g ai ha-1), dimethenamid-p (544 g ai ha-1) and EPTC (3400 g ai ha-1)] and halosulfuron (35 g ai ha-1) applied alone and in combination, applied preplant incorporated (PPI), on white bean tolerance and yield, and weed control efficacy. There was no white bean injury from the herbicide treatments evaluated. Grass herbicides (trifluralin, ethalfluralin, pendimethalin, S-metolachlor dimethenamid-P and EPTC) controlled velvetleaf 0% - 82%, pigweeds 87% - 99%, common ragweed 0% - 93%, common lambsquarters 81% - 99%, wild mustard 0% - 71%, barnyardgrass 98% - 100% and green foxtail 98% - 99%. Halosulfuron controlled velvetleaf 98%, pigweeds 94%, common ragweed 90% - 94%, common lambsquarters 97%, wild mustard 98% - 100%, barnyardgrass 19% - 24% and green foxtail 20% - 25%. Tankmixes of halosulfuron with soil-applied grass herbicides provided ≥93% control of the weed species evaluated. Reduction in density and biomass generally followed the same trend as visible control with herbicide treatments evaluated. Weed interference reduced white bean seed yield 70%. Seed yield was 53% - 66% of the weed-free control with trifluralin, ethalfluralin, pendimethalin, S-metolachlor and dimethenamid-P, 81% of the weed-free control with EPTC, 58% of the weed-free control with halosulfuron, and 87% - 95% of the weed-free control with halosulfuron tankmixes with the grass herbicides evaluated. Based on these results, halosulfuron in combination with trifluralin, ethalfluralin, pendimethalin, S-metolachlor, dimethenamid-p and EPTC, applied PPI at rates evaluated, can be used to effectively control common annual grass and broadleaf weeds in white beans.

Occurrence of Carabid Beetles in the Phenological Stages of Weedy Plants

In the current study, we investigated the relationship between the abundance of carabid species (Coleoptera: Carabidae) and the phenological stages of weedy plants growing in edge habitats. A survey of carabid beetles was conducted in edge habitats between forest fragments and soybean/corn crops or orange orchards in five sites located in northeastern S?o Paulo state, Brazil, from November 2005 to May 2008. Beetles were captured with pitfall traps, and multiple regression analysis was used to determine the carabid species that prevailed on each of the phenological stages of weeds. In total, 1115 individuals, representing 26 genera and 52 species, were captured. Selenophorus species, mainly Selenophorus seriatoporus Putzeys, Selenophorus sp.4, Helluomorphoides squiresi (Chaudoir), Tetragonoderus laevigatus Chaudoir, Athrostictus sp.1 were abundant during the reproductive phenological stages of weedy plants, which suggests that these carabid species might prefer to feed on the seeds of weedy plants.

Integrating Mechanical Weeding and Planting for Reduced Labour Input in Paddy Rice under System of Rice Intensification (SRI)

The System of Rice Intensification (SRI) has been attributed to improvement in rice production with various attributes being accrued from application of the SRI Principles. The most notable are savings on water use and increase in yield. Alternate Wetting and Drying (AWD) has also paved way for mechanical weed control in paddy fields. One of the major constraints to adoption of SRI is the perceived increased labour input due to the careful transplanting and frequent weed control. This paper evaluates the effect of mechanization on labour input in SRI in comparison to the less mechanized farmer practice. In attempt to reduce drudgery in transplanting under SRI, the drum seeder was used to establish the rice crop by direct seeding. This was then followed by using SRI practices i.e. AWD and mechanical weeding. Direct seeding using a drum seeder was compared to transplanting in both SRI and the common farmer practice. Hand weeding was also evaluated and compared to mechanical weeding. Labour input cost was also compared to the income accrued from the yields. From the study, it was noted that direct seeding using the drum seeder reduced labour input by 97% compared to transplanting. This was possible in that in direct seeding, and there was no nursery preparation and management as in transplanting. The use of a mechanical weeder reduced labour input by 28.3% in relation to hand weeding. Labour input cost for SRI was cheaper (Kshs. 124,080 per hectare) compared to the common farmer practice (Kshs. 139,117.50 per hectare). There was more yield from the SRI practice (2.75 Ton/ha) compared to the common farmer practice (1.88 Ton/ha).

Weed Management in White Bean with Variable Doses of S-Metolachlor and Halosulfuron Applied Preemergence

Five experiments were conducted in Ontario, Canada from 2016 to 2018 to determine how doses of S-metolachlor and halosulfuron applied preemergence (PRE) should be adjusted to control specific weed species in white bean. S-metolachlor, halosulfuron, and S-metolachlor + halosulfuron caused minimal (1% to 4%) injury in white bean. Weed interference reduced white bean yield 54%. On average, weed interference with S-metolachlor and halosulfuron decreased yield 34% and 29%, respectively. In contrast, white bean seed yield was similar to the weed-free control with the S-metolachlor + halosulfuron tankmixes. S-metolachlor applied alone controlled A. theophrasti, A. retroflexus, A. artemisiifolia, C. album, E. crus-galli and S. viridis 0% to 3%, 78% to 93%, 0% to 9%, 5% to 15%, 97% to 99% and 96% to 98%, respectively. Halosulfuron applied alone controlled A. theophrasti, A. retroflexus, A. artemisiifolia, C. album, E. crus-galli and S. viridis 39% to 87%, 93% to 99%, 64% to 88%, 34% to 59%, 10% to 30% and 13% to 35%, respectively. S-metolachlor + halosulfuron tankmixes controlled A. theophrasti, A. retroflexus, A. artemisiifolia, C. album, E. crus-galli and S. viridis 47% to 94%, 98% to 100%, 78% to 94%, 37% to 78%, 94% to 98% and 91% to 96%, respectively. Weed density and biomass reductions with the herbicides evaluated followed the same pattern as visible weed control assessments. Results from this study indicate that doses of S-metolachlor and halosulfuron, when applied as a tankmix, should be adjusted based on a weed species composition in each individual white bean field.

Influence of Adjuvants on the Efficacy of Tolpyralate plus Atrazine for the Control of Annual Grass and Broadleaf Weeds in Corn with and without Roundup WeatherMAX^®

Tolpyralate is a new HPPD-inhibiting herbicide that is efficacious on annual grass and broadleaf weed species in corn. For maximum herbicide performance of tolpyralate, it is recommended that atrazine is tank mixed with tolpyralate along with the adjuvants methylated seed oil concentrate (MSO) plus urea ammonia nitrate (UAN). A common use pattern of tolpyralate plus atrazine will be in a tank mix with Roundup WeatherMAX®due to the high proportion of corn acres that are seeded to Roundup Ready®hybrids in Eastern Canada. There is no information in the peer-reviewed literature if the adjuvant system in Roundup WeatherMAX®is adequate for optimal herbicide performance of tolpyralate plus atrazine, or if MSO and UAN are still required. Six field trials were conducted over two years near Ridgetown and Exeter, ON, Canada to determine if adjuvants are still required when tolpyralate plus atrazine is tank mixed with Roundup WeatherMAX®in corn. Tolpyralate plus atrazine plus MSO and Roundup WeatherMAX®plus tolpyralate plus atrazine provided excellent control of velvetleaf, pigweed spp, common ragweed, lambsquarters, ladysthumb, wild mustard, flower-of-an-hour, barnyardgrass and green foxtail in this study. Results of this study show that in the absence of Roundup WeatherMAX®, weed control with tolpyralate plus atrazine was improved substantially with the addition of MSO;however, there was little to no increase in weed control with the addition of UAN. When tolpyralate plus atrazine was co-applied with Roundup WeatherMAX®, there was no improvement in weed control with the addition of MSO and/or UAN.

Weed Management in Azuki Bean with Postemergence Herbicides

A limited number of postemergence (POST) herbicides are available for weed management in azuki bean production in Ontario. A total of three field trials were conducted during 2017 to 2019 at the Huron Research Station, University of Guelph, Exeter, Ontario, Canada to evaluate the efficacy of various postemergence (POST) herbicides for weed control in azuki bean. Fomesafen, acifluorfen and acifluorfen + Assist® caused up to 6% crop injury and weed interference reduced azuki bean yield up to 42%. Bentazon, bentazon Forte, bentazon/acifluorfen, bentazon + fomesafen + Assist®, bentazon + fomesafen + Turbocharge® and bentazon Forte + fomesafen caused up to 16% injury and weed interference reduced azuki bean yield up to 53%. Fomesafen, acifluorfen, acifluorfen + Assist®, bentazon, bentazon Forte, bentazon/acifluorfen, bentazon + fomesafen + Assist®, bentazon + fomesafen + Turbocharge® and bentazon Forte + fomesafen provided 36% to 88% control of redroot pigweed (Amaranthus retroflexus L.), common ragweed (Ambrosia artemesiifolia L.), and common lambsquarters (Chenopodium album L.). Fomesafen, acifluorfen + Assist® and acifluorfen provided 59% to 83% control of flower-of-an-hour (Hibiscus trionum L.), but bentazon, bentazon Forte, bentazon/acifluorfen, bentazon + fomesafen + Assist®, bentazon + fomesafen + Turbocharge® and bentazon Forte + fomesafen provided 78% to 99% control of H. trionum. All POST herbicides evaluated provide 99% to 100% control of wild mustard (Sinapis arvensis L.) in azuki bean. Based on these results, none of the POST herbicide evaluated that included bentazon can be used safely for the control of annual broadleaved weeds in azuki bean under Ontario environmental conditions.

直播方式对重庆地区稻田杂草群落组成和生态位的影响

为高效绿色防除重庆地区直播稻田杂草,对淹水直播和湿润直播处理下稻田杂草的群落组成和生态位进行研究。结果表明,淹水直播和湿润直播稻田的杂草群落分别由16种(隶属于9科15属)和18种(隶属于10科17属)杂草组成,水蓼(Polygonum hydropiper)和鬼针草(Bidens pilosa)为湿润直播下特有的杂草。淹水直播和湿润直播的重要杂草群落结构分别为丁香蓼(Ludwigia prostrata)+鸭舌草(Monochoria vaginalis)+稗草(Echinochloa crus-galli)和陌上菜(Lindernia procumbens)+稗草(E.crus-galli)+看麦娘(Alopecurus aequalis)+异型莎草(Cyperus difformis)。除稗草(E.crus-galli)外,两种直播方式下重要杂草的重要值均差异显著(P<0.05)。两种直播方式共有的14种重要或主要杂草中,淹水直播下光头稗(Echinochloa colonum)、稗草、异型莎草、陌上菜、看麦娘、笄石菖(Juncus prismatocarpus)、双穗雀稗(Paspalum distichum)共7种重要或主要杂草的生态位宽度较湿润直播下显著降低,且其种间(除笄石菖与双穗雀稗外)生态位叠加值或显著降低或持平。综上,淹水直播可抑制水蓼和鬼针草的萌发,从而改变稻田重要杂草的群落结构,而且可控制光头稗、稗草、异型莎草、陌上菜、看麦娘、笄石菖、双穗雀稗的数量。

On the Parable of Weeds and Wheat

This paper probes on one of the famous parables of Jesus-the Wheat and Weeds, and demonstrates some implied meaning and morals connoted in it. Through an interesting contrast between the calm restraint of the householder and high anxi ety of his slaves, this parable suggests that people should stay calm and learn from God to be tolerate and lenient religiously to"let wheat and weeds grow together until the harvest". Meanwhile, God drops a subtle hint to seed wheat positively in stead of sug gesting people to remove weeds negatively.

轻简化栽培稻田杂草发生趋势与防控技术

随着水稻轻简化栽培技术的应用与推广,东北稻区、西北稻区、长江流域稻区和华南稻区等水稻主产区的杂草种群演替加快,稗草、千金子和马唐等恶性杂草频繁发生,杂草抗药性水平上升迅速。若杂草防控不及时、不彻底,极易对水稻生产构成严重威胁。为此,对水稻直播、机插和抛秧等轻简化栽培稻田杂草的草相特征、发展趋势和防除方法等进行了概述,以期为制定合理、高效的轻简化栽培稻田杂草综合防控技术、水稻用农药减量增效除草方案,延缓杂草抗药性产生与发展提供借鉴。