Micromycetes in the rhizosphere, the rhizoplane and the roots of wheat under conventional and zero tillage

The effects of different soil cultivation on the occurrence of micromycetes in the rhizosphere, at the root surface (rhizoplane) and in the root interior were investigated in a long-term field experiment on a chernozem soil at Hru?ovany u Brna, in an area of the corn production type. Cereals were grown as a monoculture with conventional and zero tillage.Soil cultivation had no significant effect on the total number of species of micromycetes. Zero tillage resulted in an increased number of colonies isolated from the rhizosphere and the rhizoplane. On the contrary, conventional tillage resulted in an increased number of isolates from the roots interior. The abundance of individual species of micromycetes varied somewhat in individual years, larger differences being observed with the saprophytic rather than with the parasitic (Gaeumannomyces graminis, Fusarium) species. In wheat roots, Gaeumannomyces graminis was more common under conventional tillage that under zero tillage, while the reverse was true of Fusarium.     

Effects of tillage on microbial populations associated to soil aggregation in dryland spring wheat system

Tillage may influence the microbial populations involved in soil aggregation. We evaluated the effects of no till (NT) and conventional tillage (CT, tillage depth about 7 cm) continuous spring wheat system on culturable heterotrophic bacterial communities predominant in microaggregates (0.25–0.05 mm) and on soil-aggregating basidiomycete fungi in aggregate-size classes (4.75–2.00, 2.00–0.25, and 0.25–0.05 mm) at 0–20 cm depth of a Williams loam (fine-loamy, mixed, Typic Argiustolls) in dryland Montana, USA. Enzyme-linked immunosorbent assay used to quantify antigenic response to basidiomycete cell walls, was higher in NT than in CT in 4.75–2.00 mm size class in 2007 and higher in all classes and years at 0–5 cm depth, but was not different between tillage, years, and classes at 5–20 cm. The culturable bacteria from microaggregates were subjected to a soil sedimentation assay to determine their soil binding capability. The proportion of isolates which can function as soil aggregators was higher in NT than in CT at 0–5 cm but was not different at 5–20 cm. Our results provide a first insight into the beneficial effects of dryland NT compared to CT in reducing soil disturbance and residue incorporation and enriching the proportion of microorganisms responsible for aggregation, especially at the soil surface.     

Effects of tillage method and fallow frequency on leaf spotting diseases of spring wheat in the semiarid Canadian prairies

Leaf spotting diseases of wheat (Triticum spp.) are widespread in western Canada. Because these diseases are residue-borne, they are expected to be affected by changes in the quality and quantity of crop residues. A field study was conducted to determine the effects of summerfallow and tillage practices on leaf spotting diseases of spring wheat (T. aestivum L.) in the semiarid area of the western Canadian prairies. Leaf spot severity was greater in wheat grown after fallow than in continuous wheat when these systems were managed using either cultivator- or zero-tillage methods. Disease severity in wheat after fallow was similar in all three tillage methods: cultivator-, reduced-, and zero-tillage. Pyrenophora tritici-repentis (Died.) Drechs. (tan spot) was the pathogen most commonly isolated from lesioned leaf tissue. Crop residues collected in the spring of 1995 and 1996 from cultivator- and zero-tillage treatments were examined for the presence and density of fungal infective structures. The density of mature and immature structures, especially of P. tritici-repentis, was greater in residues from two years previous than in those from the previous growing season. Most of the residues in the continuous wheat system were from the previous crop. The apparent lower amount of initial inoculum available in a continuous wheat system than in wheat grown after fallow would explain the higher leaf spotting severity in the latter system. In addition, lower levels of infective structures on residues were found in wheat after fallow in zero- rather than in cultivator-tillage. However, similar disease levels in cultivator- and zero-tillage treatments suggest that the more favourable microclimate for disease development in a zero-tillage system might have compensated for the lower amounts of residue-borne inoculum.     

施磷深度和深松对春玉米磷素吸收与利用的影响

【目的】 磷肥施用深度是影响玉米对磷吸收利用的因素之一,深松可以打破犁底层,促进根系重心下移,提高根系的生理活性。研究深松措施下不同施磷深度春玉米对磷素吸收利用的影响,以期明确深松措施下春玉米高产栽培减磷增效的适宜施磷方式。 【方法】 2014年采用裂区田间试验,以耕作方式为主区,设旋耕、深松 + 旋耕两个处理;以施磷深度为副区,设6 cm (P6)、12 cm (P12)、18 cm (P18)、24 cm (P24) 4个处理,以不施磷肥为CK。2015年进行了深松措施下大田验证试验。测定了春玉米植株地上部干物质重、磷含量、磷素吸收量,分析了不同施磷深度下春玉米的磷素吸收效率和磷肥利用效率的差异性,讨论了土壤磷素分布与春玉米根系分布的匹配关系对磷素吸收和磷肥利用的影响。 【结果】 不同施磷深度下春玉米籽粒产量均表现为P12 > P6 > P18 > P24,耕作措施间表现为深松 + 旋耕处理高于旋耕处理,在深松 + 旋耕处理下P12处理与其他处理间的差异均达到显著水平。植株地上部磷含量吐丝期和完熟期均以P12处理最高,P6处理次之,P24处理最低。干物质重均以P12处理最高,耕作措施间表现为深松 + 旋耕处理高于旋耕处理,旋耕处理下吐丝期和完熟期不同施磷深度处理间差异均不显著,深松 + 旋耕处理下吐丝期不同施磷深度处理间差异均不显著,完熟期P12处理与P24处理之间的差异达到了显著水平。磷素吸收量均以P12处理最高,旋耕处理下吐丝期前P12处理较P6处理 (常规施磷深度) 提高7.47% (2014),吐丝期后P12处理较P6处理提高3.85% (2014),深松 + 旋耕处理下吐丝期前P12处理较P6处理提高10.32% (2014)、9.01% (2015),吐丝期后P12处理较P6处理提高9.34% (2014)、10.20% (2015),深松进一步促进了春玉米对磷素的吸收,且在吐丝期后表现得更为明显。磷素吸收效率均以P12处理最高,P6处理次之,P24处理最低,P12处理与其他处理之间差异均达到了显著水平。磷肥利用效率均以P12处理最高,在旋耕处理下P12处理较P6处理提高19.22% (2014),深松 + 旋耕处理下P12处理较P6处理提高29.22% (2014)、29.04% (2015)。 【结论】 深松措施下,磷肥施用深度适度下移至 12 cm 可提高春玉米的磷素吸收效率、磷肥利用效率和籽粒产量,是玉米高产栽培减磷增效的有效途径。      

保护性耕作对土壤水分和小麦产量的影响

采用3种稻田保护性耕作栽培模式与传统栽培模式的定位试验,对成都平原稻田小麦季的土壤水分及产量进行了研究。结果表明:小麦全生育期,免耕覆盖处理的土壤含水率明显地高于翻耕覆盖处理,而翻耕不覆盖处理最差;小麦分蘖高峰期,覆盖处理的土壤含水率比不覆盖处理高17.7%～75.9%,免耕覆盖处理的土壤含水率比翻耕覆盖处理高12.7%～41.0%;免耕覆盖处理的小麦最高茎蘖数又比翻耕覆盖处理增加23.8%～72.3%,均极显著优于翻耕处理;覆盖处理的小麦产量比不覆盖处理增产6.3%～19.5%,免耕覆盖处理比翻耕覆盖处理增产3.2%～8.0%。稻田保护性耕作有利于提高成都平原区小麦产量。     

不同保护性耕作措施对麦-豆轮作土壤有机碳库的影响

通过设置在甘肃省定西市李家堡镇的不同保护性耕作试验,对春小麦、豌豆两种轮作次序下的土壤总有机碳、活性有机碳、微生物量碳含量进行了测定,并计算了各处理土壤碳库管理指数.结果表明:经过5年的轮作后,与传统耕作相比,两种轮作次序下免耕秸秆覆盖和传统耕作结合秸秆还田处理均能不同程度地提高土壤总有机碳、活性有机碳、微生物量碳含量及土壤碳库管理指数,而免耕不覆盖处理除在0～5 cm提高了土壤有机碳库管理指数外,其他各层次均降低了土壤有机碳库管理指数,说明仅依靠免耕而不结合秸秆覆盖或还田对于土壤有机碳库的管理来讲是不可持续的.     

抗病性不同大豆品种根面及根际微生物区系的变化 Ⅱ.连作大豆(重茬)根面及根际微生物区系的变化

采用平板计数法测定了两个抗根腐病连作大豆品种生育期间根面和根际微生物区系动态变化。结果表明,两个品种大豆根面细菌随生育期增加呈递减趋势,品种间无差异。合丰25(H25)的根际细菌数量随生育期呈递减趋势,绥农10号(S10)根际细菌数量从三叶期到鼓粒初期不断增加,到成熟期又急剧减少。感病品种H25根瘤重明显低于抗病品种S10。H25根面真菌和镰孢霉总数在三叶期和成熟期均高于S10,苗期是根腐病的主要发病期。总之,在连作条件下,无论抗病品种还是感病品种大豆成熟期其根面和根际细菌减少,真菌和主要病原菌(镰孢霉Fusarium)都会大量富集,表明根系分泌物对根面和根际的微生物种群有选择性地促进或抑制作用。     

抗病性不同大豆品种根面及根际微生物区系的变化 Ⅰ.非连作大豆(正茬)根面及根际微生物区系的变化

采用平板计数法测定了3个抗病性不同的大豆品种在生育期内根面和根际微生物区系的变化情况,并应用荧光计数法直接测定了根际细菌和真菌的生物量。结果表明,土体的微生物种类最丰富、根际的次之、根面的较单一。播种后从三叶期到鼓粒初期,根面和根际的可培养细菌总数随生育期逐渐增加,鼓粒初期达最大值,而成熟期则有明显的下降;大豆根际细菌生物量也存在相同的变化规律。抗病性不同的大豆品种其根面、根际可培养细菌总数存在差异;抗病品种大豆的根瘤重明显高于感病品种。种植一季后感病品种根际积累的病原生物(镰孢霉Fusarium.sp.和大豆胞囊线虫Heterodera.glycines的胞囊数)明显高于抗病品种。说明大豆根系分泌物对微生物具有选择性的促进或抑制作用,不同大豆品种以及同一大豆品种在不同生育时期根系分泌物的组成和数量不同,从而使大豆根面及根际形成了特定的微生物区系组成。     

Residue,tillage and N-fertilizer rate affected yield and N efficiency in irrigated spring wheat

Yield and nitrogen (N)-content in wheat was studied under applied treatments of crop residues (legume vs. cereal), tillage depths (deep vs. shallow) and N-fertilizer rates (0, 40, 80, 120 and 160 kg ha^?1) at wheat-maize cropping systems. Experiments were conducted at Agronomy Research farm, the University of Agriculture, Peshawar Pakistan, during winter season 2009–2010 and 2010–2011 crop growth seasons. Well-chopped crop residues (5 t ha^?1) on dry matter basis of legume (Vigna unguicuata) and cereal (Zea mays) were applied to soil and subsequently plowed with mold-board plow as deep tillage (DT) and cultivator as shallow tillage (ST) treatment (main plot treatments). A month after residue and tillage application, seedbed was prepared and wheat was planted with drill in rows 25 cm apart in middle of November each year. Phosphorus and potassium were applied uniformly 80 and 40 kg ha^?1, respectively during seedbed preparation. N-fertilizer rates were applied in two splits: half 15 days after sowing (DAS) and other half 45 DAS (sub-plot treatment). Uniform cultural practices were applied during crop growth and development. Legumes residues amendments showed better responses than cereal but lower than no-residue treatment for N-content in leaf blade before anthesis (LBA), after anthesis (LAA), straw N-content (SNC), grain N-content (GNC), grain N-uptake (GNU), crop N-removal (CNR), recovery efficiency of added nitrogen (REAN), N-use efficiency (NUE), grain N-uptake (GNU) and grain yield. Likewise, shallow tillage proved better than deep tillage system for LBA, LAA, SNC, GNC, GNU, CNR, REAN, NUE, GNU and grain yield. Increased N-fertilizer from control onwards showed significant (p > 0.05) increments in LBA, LAA, SNC, GNC, GNU, CNR, N-uptake and grain yield. Treatments interaction was also found significant (p > 0.05). Study suggested, regardless of the given treatments, GNU and grain yield were in strong positive linear relationship. Legume residue incorporated shallow out yielded GNU and NUE of spring wheat in wheat-maize cropping system. It is concluded that LR and ST with 120 kg N ha^?1 ensures production of good wheat quantity and quality.     

Economics of tillage systems for spring wheat production in southwestern Saskatchewan (Canada)

The economic performance of continuous wheat (Triticum aestivum L.) and fallow-wheat rotations grown under conventional, minimum- and zero-tillage management practices on silt loam, sandy loam and heavy clay in southwestern Saskatchewan was determined during the relatively dry period of 1982–1988. The costs and returns for each rotation-tillage system were evaluated annually based on 1989–1990 price and cost conditions, and for various other plausible scenarios. Gross returns on silt loam were higher for continuous wheat (average 228 $ ha⁻¹) than for fallow-wheat systems (average 155 $ ha⁻¹). On the sandy loam, gross returns were similar for all cropping systems (average 112 $ ha⁻¹); on the heavy clay, they were higher for fallow-wheat than for continuous wheat (139 versus 119 $ ha⁻¹). Conservation tillage management increased gross returns over that obtained with conventional tillage only in years when growing season temperatures were high and precipitation was poorly distributed, or when the 21-month summerfallow period was droughty. On silt loam, gross returns were significantly lower with conservation tillage in as many as 3 of 7 years. On silt loam, net returns were highest for conventionally tilled continuous wheat when wheat prices were> 175 $ t⁻¹; at lower wheat prices, conventionally tilled fallow-wheat was the most profitable. On the other soils, minimum- and zero-tillage fallow-wheat provided the highest net returns at all wheat prices tested, with minimum tillage being slightly better at low wheat prices, but at these sites conventionally tilled fallow-wheat was not studied. The cost of production was highest for continuous wheat and for zero-tillage management. For fallow-wheat systems, conservation tillage required lower expenditures than conventional tillage for fuel, labor, machine repair and machine overheads; costs for minimum tillage averaged 9 $ ha⁻¹ and for zero tillage 15 $ ha⁻¹ lower on the silt loam. These savings were more than offset by increased herbicide costs which averaged 26 and 64 $ ha⁻¹ higher for minimum-tillage and zero-tillage systems, respectively. We concluded that producers in southwestern Saskatchean who are motivated primarily by short-term profit will find little incentive to adopt conservation tillage systems for spring wheat production, unless they are situated on soils that have already incurred severe soil loss or the soils are highly prone to further erosion losses.     

Effect of bulk density and soil water tension on denitrification in the rhizosphere of spring wheat (Triticum vulgare

Summary Pot experiments were carried out to study the influence of bulk density (D _b), soil water tension (pF) and presence of plants (spring wheat) on denitrification in a low-humus B_t-horizon of a udalf. Pots of only 5-cm depth were found to be most suitable for the experiments when using the acetylene inhibition method. Almost homogeneous soil compaction between 1.1 and 1.6g soil cm^–3 was achieved by a Proctor tamper. Water tensions were adjusted by means of ceramic plates on which negative pressure was applied. No denitrification was detected in unplanted pots. With planted pots and increasing bulk density denitrification increased more in pots with 14-day-old plants than in pots with 7-day-old plants. With 14-day-old plants N₂O emission pot^–1 increased steadily from 2 mol at D _b 1.1 to 8 mol at D _b 1.6, when soil moisture was adjusted to pF 1.5, although root growth was impaired by higher bulk density. From an experiment with different bulk densities and water tensions it could be deduced that the air-filled porosity ultimately determined the rate of denitrification. When low water tension was applied for a longer period, water tension had an overriding effect on total denitrification. Denitrification intensity, however, i.e. the amount of N₂O g^–1 root fresh weight, was highest when low water tension was accompanied by high bulk density. The results suggest that the increase in denitrification intensity at oxygen stress is partly due to higher root exudation.     

钾对春小麦产量及品质的影响

试验结果表明 ,在黑龙江省春小麦主产区白浆土和黑土上 ,钾对春小麦产量和品质都有明显的正效应 ,施钾明显提高春小麦分蘖率、单位面积有效穗数和千粒重 ,从而增加了产量。从经济效益、品质和产量综合指标分析 ,三个试点钾的适宜用量为硫酸钾 10 5 kg/ hm2 ,春小麦增产 3.1%～ 14 .9% ,使春小麦粗蛋白含量、湿面筋含量、沉降值和稳定时间各项指标都有明显增加 ,尤其是对稳定时间和湿面筋含量的效果更为明显     

河西灌区不同耕作与秸秆还田方式对春小麦出苗及产量的影响

出苗率及出苗整齐度在很大程度上决定了作物生长状况和产量丰欠,针对不同耕作措施结合秸秆还田对绿洲灌区小麦出苗及群体动态影响研究薄弱问题,研究不同秸秆还田与耕作方式对小麦出苗与产量的影响,以及二者的相关关系,对于优化耕作措施具有重要指导意义。2014—2015年,在甘肃河西绿洲灌区,通过田间定位试验,研究了不同秸秆还田和耕作措施[少耕25~30 cm高茬收割秸秆立茬还田(NTSS)、少耕25~30 cm高茬收割秸秆覆盖还田(NTS)、翻耕25~30 cm高茬收割秸秆还田(TS)和不留茬翻耕(CT)]对小麦出苗状况及产量、产量构成因素的影响,以期为优化试区小麦栽培技术提供依据。结果显示,与CT相比,NTSS、NTS降低了小麦出苗率以及出苗整齐度,TS则提高了小麦出苗率以及出苗整齐度。NTSS、NTS较CT的分蘖数分别高7.4%~10.5%、14.6%~19.1%,分蘖成穗率分别高13.5%~20.1%、33.0%~34.7%,有效穗数分别高7.5%~9.3%、10.3%~11.2%,穗粒数分别高15.7%~16.1%、18.5%~22.6%,千粒重分别高7.2%~8.9%、13.9%~14.2%,但TS与CT在以上指标间没有显著差异。NTSS、NTS与CT相比较,分别增产16.6%~17.4%、18.6%~21.4%,以NTS增产幅度较大,比TS高10.3%~11.0%。穗数和穗粒数的增加是少耕秸秆还田获得高产的主要原因,出苗率及整齐度对产量影响不显著。同时NTSS和NTS均获得较高的收获指数,提高比例分别为9.4%~10.7%与10.5%~11.1%,说明少耕秸秆还田提高籽粒产量的另一原因是提高了光合产物向籽粒中的转化。本研究表明,少耕秸秆还田是适用于试区小麦高产的理想耕作措施。     

轮耕对土壤物理性状和冬小麦产量的影响

针对华北地区土壤连续单一耕作存在的主要问题,进行了土壤轮耕效应的研究。试验选择冬小麦夏玉米玉两熟区连续5 a免耕田,设置免耕、翻耕和旋耕3种轮耕处理（即免耕一免耕,免耕一翻耕和免耕一旋耕）,冬小麦播种前进行耕作处理。研究结果表明：多年免耕后进行土壤耕作（翻耕、旋耕）可以显著降低土壤体积质量;旋耕显著降低0～10 cm土壤体积质量,翻耕则降低0～20 cm体积质量;随时间变化各处理土壤体积质量差异逐渐降低。翻耕、旋耕均显著增加了0～10 cm土壤总孔隙,同时翻耕显著增加了10～20 cm土壤总孔隙;翻耕、旋耕显著提高了5～10 cm毛管孔隙。0～10 cm土壤饱和导水率表现为旋耕＞翻耕＞免耕,翻耕、旋耕在5%水平上显著高于免耕;10～20、20～30 cm土层均表现为翻耕＞旋耕＞免耕,且10～20 cm翻耕5%水平上显著高于免耕;饱和导水率与体积质量呈显著线性负相关。翻耕、旋耕有效穗数与免耕相比分别提高了24.1%、22.3%;冬小麦的实际产量表现为：旋耕＞翻耕＞免耕,翻耕、旋耕分别比免耕增产11.8%、16.9%。总之,长期免耕后进行土壤耕作有利于改善土壤物理性状,提高作物产量。     

Coupling effects of depth of film-bottomed tillage and amount of irrigation and nitrogen fertilizer on spring wheat yield

The crop cultivation with film-bottomed tillage may benefit more, but little is known about the coupling effects of depth of film-bottomed tillage (DFBT) and amount of irrigation and nitrogen (N) fertilizer on spring wheat yield. A field quadratic regression orthogonal design experiment was conducted to determine the effects of DFBT, irrigation and N fertilization on seed yield of spring wheat (Triticum aestivum L.) in the Hexi Corridor, China from 2002 to 2005. Five levels of irrigation (143, 165, 225, 285, and 306 mm), five levels of N (45, 70, 140, 210, and 235 kg N ha⁻¹) and five DFBT (46, 60, 70, 80, and 94 cm) were investigated. Irrigation (44 mm ≤ irrigation ≤ 300 mm), DFBT (46 cm ≤ DFBT ≤ 80 cm), and N (≤160 kg N ha⁻¹) significantly increased wheat yield. DFBT, N and irrigation had a positive effect on wheat yield, in the order: irrigation > N > DFBT. The coupling between DFBT × N and, between N × irrigation had a synergistic effect on spring wheat yield. The coefficient of DFBT × irrigation was negative showing the coupling of DFBT × irrigation had a reciprocal inhibition or substitution effect. The findings suggest that spring wheat should be irrigated with 300 mm of water, with an application of 160 kg N ha⁻¹ and a 70 cm DFBT in the arid climate and sandy soil areas of China, to obtain the highest wheat yield with maximum economic benefit. The assessment with respect to N fertilizer use efficiency, environmental pollution need further research.     

不同土壤耕作模式对冬小麦籽粒品质的影响

冬小麦籽粒的品质受土壤环境影响。为了研究不同土壤耕作模式对冬小麦籽粒品质的影响,采用了5种土壤耕作模式(常规耕作秸秆不还田、常规耕作秸秆还田、旋耕秸秆还田、缺口圆盘耙耕秸秆还田、免耕秸秆覆盖)在山东龙口进行了3年田间试验,测定了冬小麦籽粒蛋白质品质、面团流变学特性和淀粉糊化特性。结果表明：少耕模式特别是旋还模式有利于改善籽粒蛋白质质量、改善面粉的加工品质,免覆模式对改变面条蒸煮品质有利。土壤耕作可改变土壤环境,但耕作方式对冬小麦品质的长期影响仍有待于进一步研究。     

不同品种小麦根际磷转化及VA菌根对小麦根际磷转化的影响

采用三室根箱研究了磷高效小麦 81( 85)-5-3-3-3及磷低效NC37两个小麦品种根际磷转化及VA菌根对根际土壤磷转化的影响。结果表明 ,磷胁迫下 ,81( 85)-5-3-3-3的吸磷量略高于NC37,两种小麦品种根际土壤均形成了明显的Olsen-P ,Ca2-P ,Ca8-P ,Al P等形态磷的耗竭区。两种小麦品种在不施磷肥和施用磷肥下接种VA菌根 ,小麦的生物量、植株磷浓度、小麦根际Olsen-P,Ca2-P ,Ca8-P,Al-P ,Fe-P的消耗量均显著增加 ;根际、非根际土壤各形态磷素的浓度梯度明显降低。     

Influence of long-term conservation tillage on soil and rhizosphere microorganisms

 In long-term field experiments on sandy loam and loamy sand soils, the influence of conservation and conventional tillage on soil and rhizosphere microorganisms was studied. Conservation tillage stimulated rhizosphere bacteria on winter wheat, winter barley, winter rye and maize in different soil layers. Particularly the populations of Agrobacterium spp. and Pseudomonas spp. were increased. On the sandy loam, N₂ fixation and nodulation of pea plants were significantly increased. No influence of different soil tillage was determined on the colonization of the rhizosphere by mycorrhiza and saprophytic fungi. Stubble residues infected with Gaeumanomyces graminis were infectious for a longer time on the soil surface than after incorporation into the soil. Received: 10 March 1998     

轮耕对渭北旱塬春玉米田土壤理化性状和产量的影响

为了揭示不同轮耕处理对渭北旱塬春玉米田土壤理化性状及春玉米产量的影响,于2008—2010年在陕西合阳设置了免耕深松免耕(NT/ST/NT)、深松翻耕深松(ST/CT/ST)、翻耕免耕翻耕(CT/NT/CT)、免耕免耕免耕(NT/NT/NT)、深松深松深松(ST/ST/ST)和翻耕翻耕翻耕(CT/CT/CT)6种轮耕模式,测定和分析了各轮耕处理下土壤容重、土壤养分与玉米产量差异。结果表明:(1)各轮耕处理降低了土壤容重,提高了土壤孔隙度,增加了田间持水量,且以NT/ST/NT处理效果最佳;与对照CT/CT/CT相比,NT/ST/NT处理0～20cm和20～40 cm土层土壤容重分别降低11.43%和9.79%,土壤孔隙度分别增加11.05%和9.87%。(2)NT/ST/NT处理对耕层0～20 cm土层土壤有机质和全氮含量影响显著(P<0.05),0～60 cm土层土壤有机质平均含量最高(10.36 g.kg 1),土壤全氮含量平均值比试验开始前和对照CT/CT/CT分别提高10.65%和4.31%;各耕作处理对0～20 cm土层土壤全氮和碱解氮含量影响较大,而对20～40 cm土层土壤有效磷和速效钾含量影响较大,保护性轮耕处理对土壤培肥效应显著(P<0.05)高于传统翻耕处理。(3)NT/ST/NT、ST/CT/ST、CT/NT/CT、NT/NT/NT和ST/ST/ST处理产量比对照CT/CT/CT处理分别增产22.42%、16.33%、3.77%、9.91%和14.18%(P<0.05),以NT/ST/NT处理春玉米增产率最高。