Cover crops and mulches influence weed management and weed flora composition in strip‐tilled tomato (Solanum lycopersicum)

This study was conducted in the Mediterranean environment of Central Italy from 2011 to 2013 with the aim of evaluating the effects of winter cover crops and their residues on weed composition in a cover crop‐tomato sequence. Treatments consisted of five soil managements (three cover crop species ‐ hairy vetch, phacelia, white mustard, winter fallow mulched with barley straw before tomato transplanting and conventionally tilled soil), two nitrogen fertilisation levels (0 and 100 kg N ha^?1) and two weed management levels (weed free and weedy) on tomato. Cover crop residues were arranged in strips on the soil surface and then used as beds for transplanting the tomato seedlings in paired rows. Rotary hoeing was performed in the bare strips between paired tomato rows. At tomato harvesting, the weed aboveground biomass and density was higher in nitrogen‐fertilised tomato than unfertilised tomato, except in hairy vetch and barley straw that showed similar values. Hairy vetch used as a cover crop and dead mulch was the most suppressive species with the highest production of residues, while phacelia and mustard were not suitable for controlling weeds. The tomato yield was high in nitrogen fertilised and weed‐free treatments, except in barley straw mulch, which showed similar values among the weed management treatments. The mulch strips caused variations in weed species composition that was mainly composed of perennial ruderal weeds, while in tilled soil, the weed flora was dominated by annual photoblastic weeds.     

Infection conditions of <Emphasis Type="Italic">Fusarium graminearum</Emphasis> in barley are variety specific and different from those in wheat

Fusarium head blight is one of the most noxious cereal diseases. Worldwide, F. graminearum (FG) and the mycotoxin deoxynivalenol (DON) is the most dominant species/mycotoxin in barley and wheat. Barley is often produced as on farm feed and thus routine mycotoxin analyses similar to those of cereals for human consumption are not performed. Hence, an early prediction of mycotoxin levels is important for farmers to minimise the risk of contaminated feed but also of contaminated cereals entering the cereal supply chain. Therefore, climate chamber experiments with artificial FG infection of barley investigating the influence of different temperatures (10 °C, 15 °C, 20 °C) and durations (4 h, 8 h, 12 h) at 99% relative humidity were conducted to accumulate data to develop a forecasting system. An up to three times higher DON contamination in the 15 °C treatments for the feed barley variety Ascona was detected compared with the 10 °C and 20 °C treatments. For the malting barley variety Concerto, the prolonged humidity durations had a stronger effect under all tested temperatures and resulted in up to two times higher DON contaminations. In addition, field experiments where spore deposition during anthesis as well as disease incidence, fungal amount and mycotoxins were observed, showed that the overwintered straw treatment resulted, depending on the year, in a three times higher FG incidence and DON content compared with the control and freshly inoculated straw treatment.     

秸秆覆盖对旱地玉米休闲田土壤水分状况影响研究

根据大田试验观测资料,研究分析了宁夏南部山区玉米休闲田进行秸秆覆盖处理后对土壤水分特征和土壤水分贮存量的影响。分析3种秸秆覆盖处理对土壤水分的垂直变差系数结果表明:传统无覆盖处理方式的土壤水分随深度的变化波动最为强烈,而整秸秆覆盖处理方式的土壤水分随深度的变化相对最弱;整个休闲期内土壤水分含量均以整秸秆覆盖处理最高,半秸秆覆盖次之,分别比传统无覆盖处理增加2.68%和1.19%,两种秸秆覆盖方式可使0~80cm土层的土壤蓄水能力对降水的敏感度提高;休闲期结束后,整秸秆覆盖处理的土壤水分贮存量(236.80mm)最高,半秸秆覆盖(224.10mm)次之,传统无覆盖(208.45mm)最低。     

长期秸秆覆盖条件下施氮对冬小麦生长的影响

通过9年定位试验,研究了秸秆覆盖(不覆盖和秸秆覆盖4 500 kg·hm~(-2))和施氮量(0、75、150、225、300 kg·hm~(-2))对冬小麦群体动态、产量三要素和籽粒产量的影响。结果表明,秸秆覆盖显著降低冬小麦越冬期分蘖数和春季总茎数,越冬期分蘖数最多降低24%,春季总茎数最大降幅为40.7%;秸秆覆盖导致单位面积穗数减少,平均降幅5.6%,但穗粒数有增加趋势,对千粒重无显著影响;与无覆盖相比,秸秆覆盖的冬小麦籽粒产量略有降低。无论秸秆覆盖与否,小麦越冬期分蘖数、春季总茎数以及单位面积穗数均与施氮量呈抛物线的关系,穗粒数随施氮量的增加而增加,千粒重则随施氮量增加而降低;施用氮肥使小麦籽粒产量最高增幅接近70%;在供试条件下,秸秆覆盖无增产效应。相比秸秆覆盖,同样小麦产量水平下,常规栽培需氮肥较少。     

不同秸秆还田模式冬麦田土壤水分特征比较

在陕西杨凌区布设田间试验,在冬小麦发育期间观测5种不同玉米秸秆覆盖与耕作方式相结合模式的土壤水分特征。结果表明5种覆盖耕作模式的土壤水分垂直变异系数大小排列为传统翻耕(0.1376)>浅旋覆盖(0.1360)>传统覆盖(0.1309)>深翻覆盖(0.1265)>免耕留茬(0.1167);免耕覆盖土壤水分贮存量(342 mm)最高,以浅旋覆盖(289 mm)、传统翻耕(287 mm)土壤水分贮存量相对为低,深翻覆盖(307 mm)、传统覆盖(300 mm)土壤水分贮存量相对居中。     

秸秆覆盖条件下不同施氮水平冬小麦氮素吸收及土壤硝态氮残留

通过田间定位试验研究秸秆覆盖条件下施氮量对小麦氮素吸收利用及土壤硝态氮残留的影响.试验包括覆盖(不覆盖和秸秆覆盖4500 kg/hm2)和施氮量(0,75,150,225和300 kg N/hm2)两个因素,共10个处理,重复3次.3年结果表明:秸秆覆盖对冬小麦吸氮量没有显著影响,但在偏旱年份,秸秆覆盖有利于提高氮肥利用效率.与不覆盖类似,秸秆覆盖冬小麦吸氮量在3年间呈持续增加趋势.不论秸秆覆盖还是不覆盖,施氮量小于等于150 kg/hm2时,对土壤硝态氮残留量均没有显著影响;施氮量高于150 kg/hm2时,土壤残留硝态氮量则显著增加,0～200 cm剖面出现明显的累积峰,秸秆覆盖土壤残留硝态氮累积峰较不覆盖处理深40 cm左右.     

Colonization of cabbage by the western black flea beetle (Phyllotreta pusilla) as affected by mulch and time of day

A 3-year study was conducted in Colorado (USA) to evaluate the response of the western black flea beetle (WBFB),Phyllotreta pusilla Horn (Coleoptera: Chrysomelidae), to different colored mulches and to determine if there were diurnal differences in the effect of mulch on their colonization on plants. The plants surrounded by aluminum mulch had the highest number of WBFB compared with the rest of the treatments in 1999 and 2000, but not in 2002; the black mulch had the lowest number of WBFB in 3 years of sampling. The highest number of WBFB were observed in the late day (4 p.m.) counting in 1999, whereas none of the treatments resulted in significant differences among early, mid, and late day counts in 2000 and in 2002. http://www.phytoparasitica.org posting May 20, 2005.     

不同覆盖方式对新疆棉田土壤温度和水分的影响

土壤温度和水分是棉花生长的重要环境因子,通过测定不同覆盖下土壤温度的变化发现,覆膜对土壤的增温效应主要表现在棉花生长前期,5月份不同程度的覆膜可使土壤温度增加0.9～2.3℃,秸秆覆盖土壤温度比无覆盖情况低3.6～6.5℃.土壤温度最大日变幅与深度可拟合成对数函数关系,且两者间有很好的相关性.在整个观测过程中秸秆和地膜覆盖对土壤都有很好的保水作用,窄膜、宽膜、全膜以及秸秆覆盖条件下土壤含水量较之裸露地可分别提高0.15%～5.01%,0.19%～5.26%,1.34%～7.71%和0.47%～4.55%.但是,覆盖秸秆在棉花的生长过程中对株高几乎没有提高作用,而不同面积的覆膜对棉花株高均有显著的促进作用.     

Effects of mulch and planting methods on Medicago ruthenica seed yield and soil physical-chemical properties

Medicago ruthenica (L.) Trautv., a wild grass species, is commonly grown as a forage crop in arid and semi-arid areas of China. Herein, we explored mulch patterns and planting methods for optimizing M. ruthenica seed production in the loess plateau of the Gansu Province, China from 2017 to 2019. The experiments comprised of six treatments including (1) flat ground without mulch (F0, control); (2) flat ground with a transparent white 0.008 mm thick plastic film mulch (FP); (3) flat ground with 4500 kg/hm² straw mulch (FS); (4) furrow with 10 cm ridges (R0); (5) furrow with plastic film mulch (RP); and (6) furrow with straw mulch (RS). Results showed that the harvested seed yield of M. ruthenica was the highest under RP treatment, followed by FP and FS treatments. Soil moisture content from mid-May to mid-August in 2017 was the highest under RP and FP treatments, followed by RS and FS treatments. In 2018, soil moisture content was the highest under RS and FS treatments. In 2017 and 2018, soil temperature was the highest under FP and RP treatments, followed by F0 and R0 treatments. Total and available nitrogen, phosphorus, and potassium contents were the highest under RS and FS treatments, followed by RP and FP treatments. Comprehensive analysis result showed that surface mulch improved soil microenvironment and increased seed yield of M. ruthenica. Straw mulch also effectively recycled excess crop straw, thereby encouraging the sustainable development of agriculture in this area. In conclusion, FS treatment was considered the best mode for M. ruthenica seed production in this area.     

Effects of mulches on water use in a winter wheat/summer maize rotation system in Loess Plateau,China

Limited water resources often result in reduced crop yield and low water productivity(WP). In northwestern China, crop production is generally dependent on precipitation. Therefore, a variety of agricultural rainwater harvesting(ARH) techniques have been used for conserving soil moisture, ameliorating soil environment, increasing crop yield, and improving water use efficiency. A two-year(2013–2015) field experiment was conducted under a typical sub-humid drought-prone climate in Yangling(108°24′E, 34°20′N; 521 m a.s.l.), Shaanxi Province, China, to explore the effects of mulching(same for summer maize and winter wheat) on soil moisture, soil temperature, crop water consumption, and crop yield with a winter wheat/summer maize rotation. Crops were planted in a ridge-furrow pattern and the treatments consisted of a transparent film mulch over the ridges(M1), a crop straw mulch in the furrows(M2), a transparent film mulch over the ridges and a crop straw mulch in the furrows(M3), a black film mulch over the ridges and a crop straw mulch in the furrows(M4), and a control with no mulch(CK). Results showed that M4 was the best treatment for improving soil water storage and content, and decreasing crop water consumption during the summer maize and winter wheat rotation. In both maize and wheat seasons, M1 had a higher soil temperature than M2 and CK, and M3 had a higher soil temperature than M4. In the maize seasons, M4 had the highest yield, WP, and precipitation productivity(PP), with the average values for these parameters increasing by 30.9%, 39.0%, and 31.0%, respectively, compared to those in CK. In the wheat seasons, however, M3 had the highest yield, WP, and PP, with the average values for these parameters being 23.7%, 26.7%, and 23.8% higher, respectively, than those in CK. Annual yield(maize and wheat yields combined) and WP did not differ significantly between M3 and M4. These results suggested that M3 and M4 may thus be the optimal ARH practices for the production of winter wheat and summer maize, respectively, in arid and semi-arid areas.     

地膜覆盖和除草剂对夏玉米田杂草及玉米生长发育的影响

研究了地膜覆盖和除草剂对夏玉米田杂草和玉米生长发育的影响.结果表明,在玉米3～5叶期施药,药后33 d,杂草数量降至最低,56％2甲4氯钠可湿性粉剂处理的杂草减退率和相对株防效分别比40 g/L烟嘧磺隆油分散制剂提高了11.71百分点和12.65百分点.揭膜后,白色地膜覆盖下杂草的平均鲜重显著低于对照,比对照减少73.25％,相对鲜重防效分别是黑色地膜覆盖、56％2甲4氯钠可湿性粉剂、40 g/L烟嘧磺隆油分散制剂处理的1.12、1.15、1.73倍.地膜覆盖出苗率高且整齐一致,平均株高和叶数比对照高,对玉米的穗粒重、百粒重及其产量有明显的增效作用,以白色地膜覆盖下玉米产量最高,增产率比黑色地膜覆盖的高1.23百分点,比40g/L烟嘧磺隆油分散制剂处理高16.09百分点;而施用56％2甲4氯钠可湿性粉剂严重影响了玉米产量的形成,其产量比对照降低3.09％.     

芽前除草剂和地膜对杂草防除和牛至生长的影响

牛至Orianum vulgare是唇形科多年生草本植物,牛至精油具有抗菌消炎功效,是重要的中兽药和饲料添加剂.牛至在苗期生长缓慢,杂草防除是牛至田建植的基础.本研究分析了芽前除草剂和地膜对牛至田杂草防控和牛至生长的影响.结果 表明,除草剂和地膜覆盖对杂草防除和牛至生长的交互效应显著.其中,覆盖黑色地膜并喷施960 g...     

基于Jensen模型的压砂地西瓜灌溉制度优化研究

针对压砂地西瓜水资源高效利用和合理灌溉制度问题,于2008年和2009年采用试坑对比试验方法进行了研究,利用水分生产函数Jensen模型分析了压砂地西瓜耗水规律及需水关键期,并用Jensen模型对压砂地西瓜灌溉制度进行了优化,结果表明:(1)压砂地西瓜全生育期耗水量为79.6~409.9 mm;(2)西瓜需水关键生育阶段顺序为"苗期开花坐果期膨大初期膨大中期伸蔓期膨大后期";(3)压砂地西瓜各生育阶段的水分敏感系数λ_1=0.6171,λ_2=0.2707,λ_3=0.0355,λ_4=0.1097,λ_5=0.1390,λ_6=0.1106;(4)通过灌溉制度优化发现:供水量范围为80~240 mm时增产效果最明显,供水量达到320 mm时,压砂地西瓜可获得高产。最优灌溉制度为:苗期灌水20~30 mm,伸蔓期灌水50~55 mm,开花坐果期灌水40~45 mm,膨大初期灌水70 mm,膨大中期灌水60~70mm,膨大末期灌水60~65 mm。     

基于HYDRUS-1D的秸秆覆盖条件下黑土区玉米田土壤水盐运移规律

为揭示不同秸秆覆盖量对黑土区玉米田农田土壤水盐运移的影响机制,基于田间试验结果,利用HYDRUS-1D模型对秸秆覆盖下农田土壤水盐运移过程进行模拟,分析不同秸秆覆盖量对土壤水盐动态的影响规律。结果表明：秸秆覆盖可以增强土壤保水性、抑制土壤盐分积累,随秸秆覆盖量增加,秸秆覆盖对土壤水盐运移的作用效果更加明显,在玉米全生育期内秸秆半量覆盖及全量覆盖较裸地40 cm耕层内各土层平均含水率分别提高3.38%~5.78%和5.26%~9.62%、平均电导率分别降低4.61%~8.93%和8.87%~12.41%。基于HYDRUS-1D模型模拟结果可知,土壤含水率模拟值与实测值的决定系数介于0.903~0.940,标准误差介于0.010~0.014 cm³·cm^-3,平均相对误差介于3.46%~4.64%;土壤电导率模拟值与实测值的决定系数介于0.817~0.853,标准误差介于0.091~0.111 mS·cm^-1,平均相对误差介于4.06%~5.46%。误差分析表明HYDRUS-1D模型模拟精度较高,能够用于模拟研究区秸秆覆盖条件下农田土壤水盐运移过程。     

Effects of weed control practices on surface-dwelling arthropod predators in tomato agroecosystems

Weed control, an important practice in agroecosystems to protect crop production, is usually achieved with herbicides. However, these pesticides are expensive, pose potential risks to the environment, may affect some beneficial organisms indirectly, and decrease overall arthropod biodiversity, including pests and their natural enemies, by removing weeds that might act as hosts or shelters for many organisms. The activity density response of important surface-dwelling arthropod predators (ground beetles [Coleoptera: Carabidae], ants [Hymenoptera: Formicidae] and spiders [Arachnida: Araneae]) to herbicides (trifluralin and paraquat), and to two alternative weed management practices (rye straw mulch and mechanical treatment to maintain weeds below threshold levels, in comparison with an untreated check), was assessed using pitfall traps. The mulch treatment had the greatest effect on activity density, reducing the number of predators trapped significantly (P<0.05). Herbicide use resulted in significant (P<0.05) reductions in the activity density of ground beetles. Most predators were trapped in the check plots — which had the highest weed biomass, followed in turn by numbers trapped in the threshold weed control treatment, the full herbicide application and the mulch treatment plots. http://www.phytoparasitica.org posting July 10, 2002.     

Growth,population dynamics,and diversity of <Emphasis Type="Italic">Fusarium equiseti</Emphasis> in ginseng fields

Fusarium equiseti is prevalent in ginseng soil, straw mulch and in ginseng root tissues and is the cause of a root surface discolouration on ginseng grown in British Columbia. Population levels of the fungus in ginseng fields ranged from 3.8 × 10³ cfu g⁻¹ soil to 1.4 × 10⁴ cfu g⁻¹ soil and were highest at 0–5 cm soil depths compared to 10–15 cm. Soil population levels were negatively correlated with S content in soil and positively correlated with Zn levels. Barley or wheat straw added to soil significantly increased population levels under laboratory conditions. Mycelial growth in culture was highest at 26–30°C and at pH 7.2–7.8. Samples of flowers and berries, and harvested seed, contained DNA of F. equiseti detected using a Fusarium-specific DNA array and the fungus was isolated from these tissues on agar medium. A high degree of genetic variation in the EF-1 alpha gene sequence was present among 52 isolates of F. equiseti which originated from ginseng fields. At least seven clades were identified. Inoculum dispersal from straw mulch used in ginseng gardens can result in seed contamination by the fungus. In addition, fungal growth near the soil surface under warm summer conditions can result in infection and crown discolouration of ginseng roots.     

氮磷营养对覆膜春玉米产量和品质的影响

对不同品种玉米在春覆膜及不同氮磷肥施用量条件下产量和籽粒主要品质变化的研究结果表明:氮肥和品种是影响玉米产量和籽粒品质的主要因素;在覆膜和露地栽培方式下,增施氮肥,玉米籽粒中蛋白质分别含量增加0.63%~0.87%、0.71%~0.75%,淀粉含量分别减少0.78%~1.74%、0.54%~1.02%;覆膜可增大不同品种玉米籽粒容重5.8~24.5g/L,增加籽粒淀粉含量0.32%~2.69%,降低籽粒中蛋白质含量0.29%~1.63%;施肥和覆膜对玉米籽粒脂肪和赖氨酸含量的影响较小。增施氮磷肥,能够明显提高玉米单产;春季覆膜栽培提高玉米单产777.00~2851.50kg/hm2。     

Weed Suppression of Living Mulch in Sugar Beets

Weed suppression in sugar beets (Beta vulgaris.) is commonly achieved with two to three post-emergent herbicide applications across the entire field. Field studies were performed, in order to investigate the weed suppressing ability of Medicago lupulina, Trifolium subterraneum and a mixture of Lolium perenne and Festuca pratensis as living mulches in sugar beet at four locations in South Germany during 2014 and 2015. Living mulches were sown 2 and 30 days after sowing (DAS) of sugar beet. Weed densities ranged from 0 to 143 plants m^?2 with Chenopodium album, Polygonum convolvulus and Polygonum aviculare being the most abundant weed species. It has been found that living mulches could reduce herbicide input up to 65?%. Weed suppression of living mulch was highest with Trifolium subterraneum (71?%). The early sown living mulches (2 DAS) revealed a 28 g m^?2 higher biomass compared to late sowing (30 DAS). However, no any linear correlation was found between living mulch biomass and weed suppression. White sugar yield (WSY) was highest in the herbicide treatments (12.6 t ha^?1). Trifolium subterraneum yielded the highest WSY of the living mulches with 11.1 t ha^?1 across all locations. Our work reveals that living mulch can play a major role in integrated plant protection by reducing herbicides in sugar beet production.     

可降解地膜对新疆南疆棉花生长和产量的影响

以诱导期为30~120 d的15种可降解地膜为供试材料,无膜及普通聚乙烯膜(Polyethylene,PE膜)为对照,于2008—2009年在新疆南疆地区的阿拉尔市开展了可降解地膜覆盖棉花的田间试验,研究可降解地膜的降解及其对棉花生长及产量的影响。结果表明:可降解地膜比普通PE膜先表现出破裂降解的现象,其中,诱导期为90 d的北京1#可降解地膜在棉田覆盖45 d后最早出现破裂;扫描电子显微镜(SEM)观察表明,与普通PE膜相比较,诱导期为80 d的北京1#可降解地膜在棉田覆盖145 d后,表面有明显的条状裂缝。覆盖可降解地膜的棉花在苗期、蕾期、开花期和花铃期的生长发育指标(株高、真叶数、单株铃数、果枝数、地上部干物质重)以及单株铃数和果枝数总体上要高于无膜处理,但是与普通PE膜处理无显著差异;覆盖可降解地膜对棉花的衣分和单铃重无显著影响;与无膜处理相比较,覆盖可降解地膜能显著增加籽棉产量,但覆盖可降解地膜与普通PE膜处理之间的籽棉产量无显著差异。     

Effects of biodegradable mulch on soil water and heat conditions,yield and quality of processing tomatoes by drip irrigation

To combat the problem of residual film pollution and ensure the sustainable development of agriculture in oasis areas, a field experiment was carried out in 2019 at the Wuyi Farm Corps Irrigation Center Test Station in Urumqi, Northwest China. Four types of biodegradable mulches, traditional plastic mulchs and a control group (bare land; referred to as CK) were compared, including a total of six different treatments. Effects of mulching on soil water and heat conditions as well as the yield and quality of processing tomatoes under drip irrigation were examined. In addition, a comparative analysis of economic benefits of biodegradable mulches was performed. Principal component analysis and gray correlation analysis were used to evaluate suitable mulching varieties for planting processing tomatoes under drip irrigation. Our results show that, compared with CK, biodegradable mulches and traditional plastic mulch have a similar effect on retaining soil moisture at the seedling stage but significantly increase soil moisture by 0.5%-1.5% and 1.5%-3.0% in the middle and late growth periods (P<0.050), respectively. The difference in the thermal insulation effect between biodegradable mulch and plastic mulch gradually reduces as the crop grows. Compared with plastic mulch, the average soil temperature at 5-20 cm depth under biodegradable mulches is significantly lowered by 2.04°C-3.52°C and 0.52°C-0.88°C (P<0.050) at the seedling stage and the full growth period, respectively, and the water use efficiency, average fruit yield, and production-investment ratio under biodegradable mulches were reduced by 0.89%-6.63%, 3.39%-8.69%, and 0.51%-6.33% (P<0.050), respectively. The comprehensive evaluation analysis suggests that the black oxidized biological double-degradation ecological mulch made from eco-benign plastic is the optimal film type under the study condition. Therefore, from the perspective of sustainable development, biodegradable mulch is a competitive alternative to plastic mulch for large-scale tomato production under drip irrigation in the oasis.