Subsoil tillage enhances wheat productivity,soil organic carbon and available nutrient status in dryland fields

Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.

Effects of Tillage and Mulch Methods on Soil Moisture inWheat Fields of Loess Plateau, China

Effects of different methods of tillage and mulch on soil moisture at fallow stage were studied in rainy andrain-deficient years. Soil moisture content per 20 cm was measured vertically within 0-300 cm soil layers in anexperiment with five treatments: deep-loosening tillage (DLT), traditional tillage (TT), plastic mulch (PM),straw mulch (SM) and plastic plus straw mulch (PSM). All mulch treatments were under no tillage conditions.Total storage of precipitation in soil from 0 to 300 cm was determined before sowing. Results showed thatthe new methods of tillage and mulch were the basic ways to improve water condition in dryland wheat fields.In a rainy year, PM with no tillage played a significant role in storing and conserving precipitation, while ina rain-deficient year, the role was not significant. Due to evaporation, DLT did not promote the storage ofsoil moisture. SM was the best way to store and conserve soil moisture. In SM treatment the wheat yieldsincreased by more than 20%.

Effects of different irrigation methods on micro-environments and root distribution in winter wheat fields

The irrigation method used in winter wheat fields affects micro-environment factors, such as relative humidity（RH） within canopy, soil temperature, topsoil bulk density, soil matric potential, and soil nutrients, and these changes may affect plant root growth.An experiment was carried out to explore the effects of irrigation method on micro-environments and root distribution in a winter wheat field in the 2007–2008 and 2008–2009 growing seasons.The results showed that border irrigation（BI）, sprinkler irrigation（SI）, and surface drip irrigation（SDI） had no significant effects on soil temperature.Topsoil bulk density, RH within the canopy, soil available N distribution, and soil matric potential were significantly affected by the three treatments.The change in soil matric potential was the key reason for the altered root profile distribution patterns.Additionally, more fine roots were produced in the BI treatment when soil water content was low and topsoil bulk density was high.Root growth was most stimulated in the top soil layers and inhibited in the deep layers in the SDI treatment, followed by SI and BI, which was due to the different water application frequencies.As a result, the root profile distribution differed, depending on the irrigation method used.The root distribution pattern changes could be described by the power level variation in the exponential function.A good knowledge of root distribution patterns is important when attempting to model water and nutrient movements and when studying soil-plant interactions.

Field Application of the Mycorrhizal Fungus <i>Rhizophagus irregularis</i>Increases the Yield of Wheat Crop and Affects Soil Microbial Functionalities

The aim of this study was to test the impact of Rhizophagus irregularis, an arbuscular mycorrhizal fungus (AMF), on durum wheat growth and soil microbial functionalities in a field inoculation trial conducted in Morocco. The results showed that i) the R. irregularis inoculum effectively improved wheat growth, ii) wheat growth promotion depended on the soil mycorrhizal infectivity and iii) functional abilities of soil microflora depended on AMF inoculation. This study confirms that field AMF inoculation can be proposed as an effective agronomic practice in wheat production and as a sustainable cultural practice to manage soil biofunctioning. To fully promote inoculation practices, a better knowledge of AMF ecology has to be acquired to better adapt AMF inoculation to environmental conditions, and thus warrant better yields and agricultural sustainability.

Grain yield losses in yellow-rusted durum wheat estimated using digital and conventional parameters under field conditions

The biotrophic fungus Puccinia striiformis f. sp. tritici is the causal agent of the yellow rust in wheat. Between the years 2010–2013 a new strain of this pathogen(Warrior/Ambition),against which the present cultivated wheat varieties have no resistance, appeared and spread rapidly. It threatens cereal production in most of Europe. The search for sources of resistance to this strain is proposed as the most efficient and safe solution to ensure high grain production. This will be helped by the development of high performance and low cost techniques for field phenotyping. In this study we analyzed vegetation indices in the Red,Green, Blue(RGB) images of crop canopies under field conditions. We evaluated their accuracy in predicting grain yield and assessing disease severity in comparison to other field measurements including the Normalized Difference Vegetation Index(NDVI), leaf chlorophyll content, stomatal conductance, and canopy temperature. We also discuss yield components and agronomic parameters in relation to grain yield and disease severity.RGB-based indices proved to be accurate predictors of grain yield and grain yield losses associated with yellow rust(R2= 0.581 and R2= 0.536, respectively), far surpassing the predictive ability of NDVI(R2= 0.118 and R2= 0.128, respectively). In comparison to potential yield, we found the presence of disease to be correlated with reductions in the number of grains per spike, grains per square meter, kernel weight and harvest index. Grain yield losses in the presence of yellow rust were also greater in later heading varieties. The combination of RGB-based indices and days to heading together explained 70.9% of the variability in grain yield and 62.7% of the yield losses.

Comparative Revenue, Obstacle Factors and Promoting Strategy of Sprinkling Irrigation in Wheat Field: A Case Study from Yanzhou, Shandong Province in China

This paper takes 30 hm2 wheat sprinkling irrigation land of Yunguo Family Farm in Yanzhou, Shandong Province, China as a sample, and draws a conclusion by comparing it with other households (including individual and large households). The conclusions are as follows: wheat sprinkling irrigation has a remarkable water-saving effect and comparative revenue. Water saving efficiency can reach 61.54% and a comprehensive income-increase rate can reach 38.67%. The main factors of increasing income and incentives of saving irrigation by sprinkling irrigation ranks as the following: saving land consolidation and water monitoring labors (accounts for 62.50%), saving land area of wheat bed to increase production and income (accounts for 23.44%), saving water bills (accounts for 14.06%). The incentive effect of water saving is not obvious mainly because the water price is low. The main obstacles to the promotion of sprinkling irrigation by individual household are the uneconomical scale and the barriers of coordination of proxy irrigation. Other large household’s (family farm) obstacles are mainly the instability of land tenure and mixed management. Suggestions on promoting sprinkling irrigation in wheat field: Accelerate land circulation and promote agricultural scale management to create basic scale conditions for spreading sprinkling irrigation;stabilizing farmland management rights as stabilizing farmland contractual rights, thus giving long-term business interests to all kinds of large household owners;guide the development of “scale + specialization” modern family farms;appropriate water saving subsidies should be given according to the positive externality of household water saving;confirm agricultural water rights to household and allow compensated transfer of “surplus water rights”.

Field Screening of Lesotho and South African Wheat Cultivars for Russian Wheat Aphid Resistance

Russian wheat aphid (Diuraphis noxia) is an international wheat pest and was first recorded in South Africa in 1978 in the Bethlehem area in the Eastern Free State. Le-sotho lies adjacent to one of the largest wheat producing areas in South Africa, the Eastern Free State, where winter wheat and facultative types are cultivated under dry land conditions. Wheat (Triticum aestivum L.) is an important crop adapted to all agro-ecological zones of Lesotho. Russian wheat aphid may have a significant impact on wheat yield. No monitoring or pest control is being done in Lesotho and at this stage there is very little information on the Russian wheat aphid resistance of wheat culti-vars cultivated in Lesotho. In view of this it is important to monitor the distribution of Russian wheat aphid biotypes in Lesotho and determine the level of Russian wheat aphid resistance in local Lesotho wheat cultivars. Two local Lesotho wheat cultivars, Bolane and Makalaote were screened together with South African cultivars Elands, Matlabas, Senqu, PAN3379, PAN3118 and SST387, in the glasshouse against all four known biotypes that occur in South Africa. All these cultivars were also planted in 5 m plots in the field at two localities Leribe and Roma in the lowlands of Lesotho. These cultivars were screened in the field for Russian wheat aphid resistance. The predomi-nant Russian wheat aphid biotypes in these areas were also determined. The Lesotho cultivar, Bolane had resistance against RWASA2 in the glasshouse, while Makalaote did not have any Russian wheat aphid resistance in either the glasshouse or field screenings. To contribute to food security an increasing wheat yield potential is a high priority. Russian wheat aphid has been included in the list of important international cereal pests. Russian wheat aphid adapts to changing environments and taking their ecology, distribution, virulence patterns, and variability into account is important in minimizing the gap between actual and attainable yields. Current management prac-tices for winter wheat in South Africa include the use of resistant cultivars, which is the most economical management strategy for Russian wheat aphid. Introducing Russian wheat aphid resistant cultivars in Lesotho will improve overall yield and as a result food security. This will also result in lower Russian wheat aphid pest pressure in the adjacent wheat production areas in the Eastern Free State, South Africa.

稻麦轮作高标准农田控制排水对排水与氮素输出削减效果模拟

稻麦轮作区高标准农田建设中,通过加深排水沟提高麦作期农田排水降渍能力的同时,加大稻作期农田排水输出,不仅降低了水资源利用效率,而且加重了接纳水体的污染。本文基于江苏省扬州市沿运灌区稻麦轮作农田排水水文水质过程的监测结果,利用田间水文模型(DRAINMOD)模拟了长序列气象条件下,灌区提高农田降渍能力对稻田排水、氮素流失及灌溉需求的负面影响以及控制排水措施的积极效果。结果表明,在节水灌溉模式下,研究区排水沟深度由现状的60 cm加深至120 cm,排水间距由120 m加密至20 m时,稻作期排水量与总氮(TN)输出负荷增加9.0%~22.2%、氨氮(NH_(3)-N)输出负荷增加4.0%~16.8%、灌溉用水量增加9.6%~23.4%。若结合田间管理要求,实施控制排水则可有效缓解提高农田降渍能力造成的负面影响;当排水沟深为120 cm,间距为120~20 m时,稻作期控制排水可使排水量和TN输出负荷减少19.3%~35.3%、NH_(3)-N输出负荷减少7.6%~27.2%、灌溉用水量减少22.9%~40.0%。由于控制排水降低了地下排水梯度,相较于传统排水,农沟从60 cm加深至120 cm时,地下排水平均占比降至50.7%,灌溉用水量相应减少。综上,稻麦轮作农田控制排水具有显著的节水减排作用,可有效降低高标准农田建设中提高降渍能力所产生的负面影响。研究成果可为稻麦轮作区高标准农田建设与水环境保护提供理论依据与技术支撑。

玉米秸秆长期还田配施氮肥对不同筋性小麦品质和产量的影响

为研究玉米秸秆还田配施氮肥对不同筋性小麦品质和产量的影响,采用玉米秸秆还田(SR)、玉米秸秆不还田(NSR)为主因素,0、90、180、270、360 kg·hm^(-2)5个施氮量为副因素的裂区设计,测定了小麦千粒质量、容重、产量、硬度、蛋白质、湿面筋、沉降值、吸水率、面团形成时间、面团稳定时间、延展性、最大延伸阻力和延伸面积等指标。结果表明:玉米秸秆还田降低了小麦的蛋白质和湿面筋含量,且中筋小麦青农2号的降幅大于高筋小麦济南17;玉米秸秆还田显著降低了青农2号的硬度、沉降值、吸水率、面团形成时间和延展性,显著提高了济南17的硬度、吸水率、延展性、最大延伸阻力和延伸面积;2个小麦品种的蛋白质、湿面筋含量均随着施氮量的增加而增加;青农2号的沉降值、吸水率、面团形成时间、面团稳定时间、延展性、最大延伸阻力和延伸面积均随着施氮量的增加而增加,而济南17的吸水率、延展性、最大延伸阻力和延伸面积在施氮量为180 kg·hm^(-2)时最高,沉降值、面团形成时间、面团稳定时间在施氮量为270 kg·hm^(-2)时最高;SR显著提高了小麦产量,比NSR增产15.2%~31.0%,且施氮量为180 kg·hm^(-2)时,小麦产量最高。因此,中筋小麦青农2号的最佳种植模式为玉米秸秆还田+施氮180 kg·hm^(-2),高筋小麦济南17的优质高产栽培模式为玉米秸秆还田+施氮180~270 kg·hm^(-2)。

冬小麦-夏玉米轮作田沟金针虫垂直活动特征

基于河北固城农业气象国家野外科学观测研究站2019—2020年、2021—2022年冬小麦-夏玉米轮作田沟金针虫在土壤中分层调查数据,引入虫口重量指标,结合虫口密度指标,揭示沟金针虫在冬小麦-夏玉米轮作田为害-休眠动态变化,讨论沟金针虫在土壤中垂直活动特征、气象条件与其相关性以及对冬小麦产量影响。结果表明:沟金针虫在冬小麦-夏玉米轮作田存在3个为害期和3个休眠期,且交替出现。3个为害期出现在冬小麦返青-拔节期、夏玉米幼苗期、冬小麦秋苗期,3个休眠期出现在冬小麦越冬期、冬小麦成熟-收获期、夏玉米灌浆-成熟期,3个为害期中以冬小麦返青-拔节期最为严重。冬季偏暖及春季回暖早,沟金针虫表现出晚下早上特征,使得沟金针虫冬季休眠期缩短而为害活动期延长;土壤温度、湿度以及食源关系共同影响沟金针虫为害、休眠以及取食活动,其为害适宜土壤重量含水率约为15%~18%,适宜土壤温度为14~18℃。分析沟金针虫为害与冬小麦减产率可知,虫口密度每增加10 m^(-2)或虫口重量每增加1.0 g·m^(-2),可导致减产率增加5.1%。

江汉平原典型种植模式稻田土壤中农药残留特征

在江汉平原中稻-油菜/小麦轮作田、一季中稻田及再生稻田3种种植模式稻田采集土壤样品86个。调查了土壤样品中滴滴涕(DDTs,包括o,p′-DDT、p,p′-DDT、p,p′-DDE、p,p′-DDD)、六六六(HCHs,包括α-HCH、β-HCH、γ-HCH、δ-HCH)、甲胺磷、甲基对硫磷、氧乐果、乐果、敌敌畏、乙酰甲胺磷、毒死蜱、氯虫苯甲酰胺、吡蚜酮、吡虫啉、啶虫脒、三环唑、戊唑醇、氰氟草酯、二氯喹啉酸、乙草胺及异丙甲草胺等25种农药及其代谢产物的残留。结果表明,检出率最高的3种农药为当前常用杀虫剂氯虫苯甲酰胺(87.21%),杀菌剂三环唑(91.86%)及戊唑醇(72.09%),其残留均值分别为0.0397、0.0734 mg/kg及0.0276 mg/kg;已经禁用的有机氯农药滴滴涕(o,p′-DDT、p,p′-DDT、p,p′-DDE、p,p′-DDD)仍能检出,检出率为36.05%~66.28%。3种模式田块中检出的滴滴涕主要来源于历史上滴滴涕的使用。杀虫剂吡蚜酮及杀菌剂三环唑在再生稻田的残留量均值显著高于中稻-油菜/小麦轮作田及一季中稻田;但其他农药在不同种植模式稻田中的残留没有显著差异。本研究为江汉平原农药残留的治理及农药的合理使用提供了参考信息。

夏闲季不同耕作措施对旱地麦田土壤养分含量和酶活性的影响

为明确夏闲季不同耕作措施对旱地麦田土壤理化特性和酶活性的影响,基于2018年开始设置在黄土高原与黄淮海平原交汇处典型旱作区洛宁县小界乡的夏闲季定位耕作管理大区试验,2020—2022年研究了传统翻耕(CT)、一次深翻(DT)、免耕覆盖(NTM)、深松覆盖(STM)和深松垄沟覆盖(SRFM)5种夏闲季耕作措施对旱地麦田土壤三相比、养分含量和酶活性的影响。结果表明,优化夏闲季耕作措施可改善旱地麦田土壤三相比,提高土壤养分含量和酶活性,总体以SRFM效果最好。与CT相比,STM和SRFM的三相比R值显著降低4.7%~28.2%和10.9%~33.7%,DT、STM和SRFM在0~40 cm土层土壤全氮含量分别提高2.8%~11.2%、11.7%~21.4%和15.6%~30.6%,有效磷含量分别提高6.9%~39.5%、7.4%~68.8%和13.6%~80.3%,速效钾含量分别提高5.2%~19.7%、9.6%~25.8%和13.8%~35.0%;土壤蔗糖酶活性分别提高7.8%~21.5%、17.1%~75.9%和27.9%~99.1%,脲酶活性分别提高7.6%~97.0%、12.8%~165.5%和23.5%~194.9%,过氧化氢酶活性分别提高5.5%~15.2%、16.3%~26.7%和20.8%~50.3%,增幅多达到显著水平且表现为SRFM>STM>DT,NTM可显著提高0~10 cm土层但降低20~40 cm土层土壤养分含量和酶活性。综合来看,夏闲季深松垄沟并结合秸秆覆盖的措施可改善土壤三相比,提高土壤养分含量和酶活性,是利于提高旱地麦田土壤质量的耕作措施。

秸秆还田配施化肥下麦田土壤理化性质和酶活性的变化

为了探明长期秸秆还田下配施化肥对麦田土壤酶活性的影响及其主要驱动因子,以持续4年的广水长期定位试验为依托,设置秸秆(S,用量为6000 kg/hm^(2),其他处理用量相同)、秸秆+施100%N(S100N,纯N用量为187.5 kg/hm^(2),其他施肥处理用量按此用量折算)、秸秆+施80%N(S80N)、秸秆+施60%N(S60N)、秸秆+施80%N+菌剂(S80Nm,秸秆腐熟菌剂用量为30 kg/hm^(2))、秸秆+施60%N+菌剂(S60Nm,菌剂用量同S80Nm)6个处理,测定了土壤酶活性、土壤理化性质及小麦产量。结果显示,与S相比,S100N和S80N小麦产量分别显著提高182.82%和179.55%(P<0.05);秸秆腐熟菌剂的添加对土壤理化性质和小麦产量的效果不显著。与S100N相比,S80N增加了土壤磷酸酶(Phos)、硫酸酯酶(Sul)、β-葡萄糖苷酶(βG)、β-木糖苷酶(βX)、α-葡萄糖苷酶(αG)、乙酰氨基葡萄糖苷酶(NAG)和亮氨酸氨基肽酶(LAP)的活性;冗余分析(RDA)显示秸秆还田条件下,土壤有机质和碱解氮的含量是土壤酶变化的主要影响因子。因此,从减肥增效角度来看,S80N是提升土壤质量较适宜的管理措施。

“一眼看得见”的语言——论梅子涵晚近散文集《黄麦地》

梅子涵从事文学创作近50年,在散文语体和题材方面形成了鲜明的特色,一种基于平等理念的创作,交织起儿童和成人不同的思维方式,以自觉的“看得见”形象捕捉,彰显了主体特色,扩大了创作视野,给他的散文创作注入了源源不断的活力。梅子涵的主体位置,在散文的每一篇都清晰可见,可以认为他是一个非常“自恋”的人。这种“自恋”既是对人的特征,也是对他散文基调的概括,是儿童化思维方式的体现。

不同季秸秆还田对冬小麦不同穗粒位结实粒数和粒重的影响

为探讨安徽淮北平原砂姜黑土区长期秸秆连续全量还田对冬小麦穗部结实特性的影响,2021-2022年基于农业农村部华东地区作物栽培科学观测站13年的长期定位试验,比较分析了小麦单季秸秆全量粉碎覆盖还田(T1)、小麦玉米秸秆全量粉碎还田(T2)、玉米秸秆全量粉碎翻埋还田(T3)、小麦玉米秸秆全年不还田(CK)4个不同还田模式下小麦不同小穗位结实粒数及粒重的差异。结果表明,T1、T2、T3处理的主茎穗小穗结实总粒数较CK分别提高了21.21%、7.50%和12.55%;第2粒位(G2)结实粒数分别提高了7.71%、7.71%和5.79%;上部小穗结实粒数分别提高了51.41%、22.79%和31.36%,其G2结实粒数分别提高了30.95%、30.95%和23.09%,其中T1处理对小麦粒数的提升效果最好。不同季秸秆还田处理下小麦主茎穗及其G2粒重、分蘖穗及其第三粒位(G3)粒重均高于CK,T1、T2和T3处理的主茎穗粒重增幅分别为16.06%、4.14%和16.06%,分蘖穗增幅分别为9.86%、0.71%和8.87%;T1、T2和T3处理下主茎穗G2粒重增幅分别为20.69%、10.34%和17.24%,分蘖穗G3粒重4.55%、2.27%和6.82%,其中T1处理对粒重提升效果最好,其次是T3。综合来看,在安徽淮北平原砂姜黑土区长期秸秆还田能够提高小麦穗粒数和粒重,进而促进产量提升,其中T1处理对小麦结实粒数和粒重的提升效果最好,是适宜在该地区推广的秸秆还田模式。

不同种植方式对高寒旱区地膜小麦耗水特征和产量的影响

于2019—2022年在陇中高寒旱区以裸地条播为对照(CK),设置全膜覆土穴播(FM)和膜侧沟播(FS)两种覆盖方式,研究不同覆盖种植方式对冬小麦耗水特性、生长发育及产量的影响。结果表明:与CK相比,FM和FS处理播种期~拔节期0~20 cm土层土壤温度分别平均提高3.1℃和2.1℃,灌浆期分别降低0.6℃和1.0℃。覆盖能不同程度提高冬小麦各生育期0~200 cm土层土壤含水量,其中出苗期、返青期、拔节期和灌浆期提高幅度均高于20%。与CK相比,FM处理返青后冬小麦耗水量平均显著提高29.2%,返青前显著降低42.4%;FS处理返青期~灌浆期耗水量提高12.6%,返青前降低25.7%。各处理冬小麦基本苗、分蘖数、公顷穗数、穗粒数、千粒重和产量均表现为FM>FS>CK,处理间差异显著,其中FM和FS处理产量分别较CK平均提高74.7%和45.4%;处理间耗水量差异不显著;FM处理水分利用效率最大,较CK平均提高67.3%,FS次之,较CK平均提高46.1%。综上,地膜覆盖可调节土壤水分状况,改善冬小麦生长发育和成穗情况,显著提高产量和水分利用效率,其中全膜覆土穴播调节效应优于膜侧沟播,是适宜在高寒旱区地膜小麦生产中推广应用的种植方式。

我国主要麦区土壤有效铁锰铜锌丰缺状况评价及影响因素

明确我国主要麦区土壤有效铁锰铜锌含量分布和影响因素,对了解麦田土壤微量元素供应能力、指导小麦丰产与优质生产至关重要。于2016-2021年连续6年,在我国17个小麦主产省/市采集1314份耕层土壤样品,参考中国土壤有效微量元素分级标准,评价了我国麦田土壤有效铁锰铜锌丰缺状况,并采用随机森林方法定量分析了主要土壤化学性质对铁锰铜锌有效性的贡献。结果表明,我国主要麦区土壤有效铁含量介于1.8~612 mg·kg^(-1),平均为49.1 mg·kg^(-1),8.9%的样本未达到缺铁临界值4.5 mg·kg^(-1),且主要集中在北方、西北麦区的山西、陕西、甘肃等地,西南和长江中下游麦区有效铁较高。土壤有效锰介于0.1~176 mg·kg^(-1),平均为22.1 mg·kg^(-1),低于缺锰临界值5 mg·kg^(-1)的样本占6.9%,缺锰土壤分布在西北、北方麦区的山西、陕西、甘肃、内蒙古等地,西南、长江中下游麦区土壤有效锰含量较高。土壤有效铜介于0.1~10.8 mg·kg^(-1),平均为1.9 mg·kg^(-1),仅1.8%样本未达到缺铜临界值0.5 mg·kg^(-1)。土壤有效锌介于0.1~26.0 mg·kg^(-1),平均为1.4 mg·kg^(-1),14.3%的样本低于缺锌临界值0.5 mg·kg^(-1),主要分布在西北和北方麦区的山西、陕西、甘肃、内蒙古等省份,云南、贵州等西南麦区的有效锌较高。土壤基本化学性质中,pH对有效铁、有效锰含量影响最大,有效铁是铜有效性的重要因素,影响有效锌的主要因素是有效磷和有效铜。我国麦田土壤有效铁锰铜锌含量存在较大的区域变异,铁、锰、锌不足主要发生在北方石灰性土壤,南方麦田供应充足,几乎所有麦田土壤有效铜可满足作物铜需求。

叶菌唑与氟唑菌酰羟胺对小麦赤霉病的复配增效研究

为探索叶菌唑与氟唑菌酰羟胺复配对小麦赤霉病菌的增效作用,采用菌丝生长速率法对两种原药进行室内联合毒力测定。结果显示叶菌唑与氟唑菌酰羟胺质量比为1.5∶1时,增效系数最大。在此基础上进行田间药效试验,结果表明8%叶菌唑悬浮剂70 g/667m^(2)+18%氟唑菌酰羟胺悬浮剂20.7 g/667m^(2)处理的效果最好,防效为83.57%,其次为8%叶菌唑悬浮剂55 g/667m^(2)+18%氟唑菌酰羟胺悬浮剂16.3g/667m^(2),防效达到78.01%。复配处理中高剂量的防效均显著高于两种单剂的推荐剂量,且试验期间没有对非靶标生物产生影响,建议在生产中使用该剂量。

青海省春小麦田杂草群落组成及其多样性分析

为明确青海省春小麦田杂草发生种类及其群落特征,采用倒置“W”九点取样法对青海省东部农业区和柴达木盆地农业区春小麦田杂草种类、生活型、科属组成、群落结构及杂草多样性进行调查。统计分析发现:小麦田有85种杂草,隶属24科64属。其中,菊科和禾本科是数量最多的科别,杂草分别为16种和14种。从杂草的综合优势度来看,藜(Chenopodium album L.)、野燕麦(Avena fatua L.)、萹蓄(Polygonum aviculare L.)、苦苣菜(Sonchus oleraceus L.)、苣荬菜(Herba Sonchi Brachyoti)5种杂草为优势杂草,芦苇(Phragmites australis(Cav.)Trin.)、赖草(Leymus secalinus(Georgi)Tzvel.)、狗尾草(Setaria viridis(Linn.)Beauv.)、藏蓟(Cirsium eriophoroides)、荞麦蔓(Fagopyrum esculentum Moench.)、节裂角茴香(Hypecoum leptocarpum Hook.f.et Thoms.)、猪殃殃(Galium spurium L.)、大刺儿菜(Cirsium arvense var.setosum(willd.)Ledeb)、密花香薷(Elsholtzia densa Benth.)、野油菜(Brassica juncea(L.)Czern.et Coss.)10种杂草为区域性优势杂草。此外有常见杂草22种,一般性杂草48种。东部农业区田间杂草物种丰富度较柴达木地区高,湟中区、大通县、互助县麦田杂草的物种丰富度依次为46、45、42;柴达木盆地的都兰县、德令哈市、乌兰县、格尔木市麦田杂草的物种丰富度依次为30、26、23、13,调查区以格尔木市的物种丰富度最小。比较杂草的生活型发现,同一地区越年生杂草、多年生杂草的发生数量和一年生杂草的数量基本接近50%;从杂草群落的相似性来看,东部农业区的湟中区、互助县、大通县杂草群落组成极为相似,而柴达木盆地绿洲农业区的都兰县、德令哈市、格尔木市、乌兰县杂草群落相似性程度高,杂草群落结构的相似性结果与区域小麦生产实际相吻合。群落结构组成和区域耕作制度、气候条件、土壤理化性质、田间管理水平等具有较大的相关性,建议加强杂草优势种和区域性优势杂草的防控和监测,因地制宜制定杂草绿色防控措施。

基于GF-1卫星影像数据融合的冬小麦田空间信息提取

为给高标准农田建设规划和粮食安全生产措施的制定提供准确信息,在对国产GF-1/PMS卫星影像进行辐射定标、大气校正、几何校正和裁剪等预处理的基础上,经过影像融合提取了高标准麦田多地物的点像元光谱信息,通过分析不同地物光谱特征,利用波段反射率、归一化差值植被指数(NDVI)和差值植被指数(DVI)构建植被光谱特征指标阈值,进而对冬小麦田及非麦田进行分类,以获取高标准麦田的空间分布信息。结果表明,光谱特征指标选择BR_(4)>0.3、NDVI>0.619和DVI>0.317,可以较准确地从影像中识别出冬小麦田,并减少田间道路被误判为冬小麦田像元。在非麦田分类中,选择BR_(3)>0.15和BR_(4)>0.2,可将建筑用地与河流(沟渠)区分开。利用田间样方统计面积和遥感提取面积进行精度验证,总体精度可达97.33%,说明通过中、高空间分辨率遥感数据融合,结合多重光谱特征指标建立合理的分类阈值,可以准确提取冬小麦田及非麦田的分布信息。