Physical and mechanical properties of a clayey soil as affected by tillage systems for wheat growth

Abstract

The effect of tillage systems on soil physical properties of a clayey soil was studied. Tillage systems consisting of conventional tillage I (CT₁), conventional tillage II (CT₂), reduced conventional tillage (RCT), reduced tillage (RT) and no tillage (NT) were carried out in autumn after harvest of sugar beet. Significant differences between tillage systems were recorded on the measured properties, apart from moisture content, at 15–30 cm soil layer. The CT₁, CT₂ and RCT systems resulted in similar penetration resistance and bulk density values below the 15 cm soil depth, while the RT and NT systems resulted in higher but similar values. The mean penetration resistance values were less than 1 MPa in the CT₁, CT₂ and RCT systems at the 0–15 cm depth, while they were 1.41, 1.84 MPa in RT and NT, respectively. The mean total porosity increased with tillage from 8.2 to 28% when compared with NT. The CT₁, CT₂ and RCT systems resulted in lower moisture content at the 0–15 cm depth. The lowest moisture content occurred in RCT (24.4%) and the highest in NT (30.9%), while it was 30.3% in RT system. The lowest and highest mean weight diameter values were reported for the RT (1.36 mm) and NT (2.37 mm) systems, respectively. The lowest wheat grain yield was obtained in NT (4.14) and the highest in CT₁ (5.24 Mg ha^?1). A significant difference occurred between only NT and the other systems. When both grain yield and advantages of reduced tillage are considered, the RT system is recommended.     

耕作方式对长期免耕农田土壤微生物生物量碳的影响

以华北冬小麦-夏玉米两熟区长期免耕土壤为研究对象, 研究不同耕作方式(免耕、翻耕和旋耕)对长期免耕土壤微生物生物量碳(SMBC)的影响, 为制定合理的轮耕制度提供依据。试验结果表明: 长期免耕土壤进行耕作处理后SMBC 的时空分布和稳定性产生显著变化。不同耕作处理SMBC 含量在0~5 cm 和5~10 cm 土层变化明显, 小麦起身期含量最低, 收获期最高; 深层SMBC变化不明显。免耕处理SMBC 随土壤层次明显降低, 且各土壤层次SMBC 差异达显著(P<0.05)水平; 翻耕、旋耕处理0~5 cm 和5~10 cm 土层间SMBC 无明显差异, 其他层次间差异显著(P<0.05)。从生育期平均值看, 0~5 cm 土层免耕处理SMBC 含量较高, 翻耕和旋耕处理则分别比免耕降低6.7%、6.1%; 与免耕相比, 5~10 cm 土层SMBC 翻耕、旋耕处理分别增加30.2%和20.7%(P<0.01),10~20 cm 土层SMBC 翻耕、旋耕处理比免耕增加48.1%(P<0.01)和10.5%(P<0.05)。在冬小麦生育期内, 0~20 cm土层SMBC 稳定性表现为翻耕>旋耕>免耕, 20~30 cm 土层SMBC 稳定性表现为免耕>翻耕>旋耕。     

The erosion threshold for a sustainable agriculture in cultures of bean (Phaseolus vulgaris L.) under conventional tillage and no‐tillage in Northern Nicaragua

Soil erosion by water is one of the main environmental problems of the tropical mountains of Central America. The fragility of these areas, the significant degree of human population pressure exerted and changes in traditional farming systems all contribute to the current state of degradation. In this study, we compare two types of agricultural management (conventional tillage with traditional ploughing and no‐tillage with a digging stick) and analyse the influence of land slope, the management of vegetation cover, and various soil features and properties related to erosion in fields dedicated to the cultivation of beans (Phaseolus vulgaris L.) to determine the erosion thresholds. The study area was located in the hills around El Cuá, in northern Nicaragua. The results showed the system of no‐tillage (NT) to be more effective at controlling erosion than conventional tillage (CT), such that 28.7% less land was affected by erosion. Erosion in plots under CT did not present any statistically significant relationship with the factors analysed. Conversely, the erosion in the plots under NT was significantly related to the coverage of vegetation residues, and we calculated an erosion threshold of 40% of the level of vegetation coverage, which significantly reduces erosion.     

黑土区覆混耕作中玉米秸秆还田对土壤水分入渗性能的影响

覆盖混埋耕作主要通过联合整地机对秸秆进行切碎并均匀混入土壤,对降低风蚀水蚀、提高耕层土壤蓄水能力及构建优质种床具有重要作用。为探究覆混耕作中玉米秸秆对土壤水分入渗性能的影响,该研究利用Design Expert软件,根据Box-Behnken试验原理通过室内土柱模拟试验,以覆混耕作中秸秆混埋深度、秸秆混埋量、秸秆长度为影响因素,以渗水量为指标进行三因素三水平二次回归正交试验。通过建立响应面数学模型,分析了各因素对土壤水分入渗性能的影响,并对影响因素进行了综合优化。试验结果表明：对渗水量影响主次顺序为秸秆混埋深度、秸秆长度、秸秆混埋量;当秸秆混埋深度为20 cm、秸秆混埋量为80%、秸秆长度为9 cm时,渗水量达到最优值0.249 L。利用优化后的参数进行试验验证,土壤渗水量为0.247 L。研究结果可为覆混耕作中联合整地机的作业参数调整提供参考和土壤水分入渗性能研究提供参考。     

免耕秸秆还田和传统耕作方式下东北黑土氨基糖态碳的积累特征

以吉林德惠市中层黑土进行7年田间定位试验的小区土壤为研究对象,对免耕(NT)和传统耕作下(CT)耕层(0～20 cm)氨基糖态碳含量的变化特征进行了分析。结果表明,与传统耕作相比,实施免耕7年后整个耕层土壤中氨基糖态碳含量显著增加(p<0.05),以表层(0～5 cm)增加幅度最大,高达94.7%。说明在研究地区,免耕措施有利于微生物代谢物如细胞壁物质等作为潜在的碳源逐渐积累在土壤中。免耕土壤中不同微生物来源氨基糖态碳的含量均较传统耕作有显著增加,但是变化特征有所不同,其中免耕条件下真菌来源的氨基葡萄糖的积累量较传统耕作高出1倍多,而且氨基葡萄糖与细菌来源的胞壁酸的比值(6.9～7.3)显著高于传统耕作(4.7～5.4),暗示实施免耕秸秆还田7年后土壤中真菌已逐渐转为优势群体,而真菌占优势的农田生态系统具有更大的固碳潜力。     

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。     

耕作方式对东北黑土坡耕地土壤物理性状及根系垂直分布的影响

为了明确耕作方式对东北薄层黑土坡耕地土壤物理性状以及玉米根系垂直分布的影响,该研究以东北薄层黑土坡耕地土壤为研究对象,设置免耕和翻耕2种耕作方式,研究耕作方式对不同坡位土壤水稳性团聚体粒径分布与稳定性、土壤容重、土壤孔隙度、土壤贯入阻力以及玉米根系在垂直方向主要分布深度的影响,并进一步探究各指标间的相互关系.结果表明,...     

小麦/玉米/大豆和小麦/玉米/甘薯体系中玉米产量及养分吸收的差异

分别在四川2个玉米主产区川中丘区射洪县和川西山区雅安市,采用单因素随机区组设计,通过3年田间试验对比研究了小麦/玉米/大豆和小麦/玉米/甘薯模式下玉米产量、养分吸收积累规律以及与耕层土壤养分的关系。结果表明:两种套作模式经过一年种植后,小麦/玉米/大豆模式下玉米产量均高于小麦/玉米/甘薯模式下的玉米产量,但差异不显著,第二、三年分带轮作后,小麦/玉米/大豆模式下玉米产量显著高于小麦/玉米/甘薯模式下的玉米产量,二年平均分别高出 679.5 kg/hm2和 839.1 kg/hm2,增产9.4%和12.6%,射洪试验点增产作用较雅安试验点显著;分带轮作后两种套作体系玉米氮素吸收积累在拔节前差异不显著,拔节后小麦/玉米/大豆模式下玉米氮素积累量显著高于小麦/玉米/甘薯,磷的吸收积累则相反,从拔节期到开花期,小麦/玉米/大豆模式下玉米磷的吸收积累均显著低于小麦/玉米/甘薯,小麦/玉米/大豆模式下玉米钾素吸收积累量高于小麦/玉米/甘薯;不同作物带耕层土壤养分含量差异达显著水平,大豆带残留的硝态氮、速效氮、速效钾2个试验点平均分别比甘薯带高18.4%、24.1%、6.0%,而铵态氮和速效磷甘薯带较大豆带分别高18.9%和17.1%,两种套作模式中玉米带耕层土壤养分含量差异不显著,经第二、三年分带轮作后,耕层土壤养分含量差异减小,表明分带轮作玉米能较好均衡田间养分。     

Greenhouse gases emission,soil organic carbon and wheat yield as affected by tillage systems and nitrogen management practices

Agricultural activities are responsible for greenhouse gases (GHGs) emission in the environment. Strategies are required to enhance the soil organic carbon (SOC) and nitrogen (N) sequestration to adapt and mitigate the climate change. We investigated GHGs emission, SOC and N enhancement under conventional tillage (CT) and zero tillage (ZT) with N management in wheat (Triticum aestivum L.). Seasonal carbon dioxide (CO₂) emission and global warming potential (GWP) reduced for ZT treatments over CT without residues and 100% of required N with a blanket split application (CT – R + 100N). The ZT with 5 t ha^?1 maize (Zea mays L.) residues retention and 75% of required N and GreenSeeker^TM (GS)-aided N management (ZT + R + 75N + GS) reduced yield-scaled GHGs emission and increased total organic carbon (C) stock over CT – R + 100N. However, nitrous oxide (N₂O) emission was lower in CT. The GS-based N management saved 26–35 kg N ha^?1 in different tillage systems in both years over blanket application with higher N uptake and associated reduction in N₂O emission. The study recommends that ZT with residues retention and GS-based N management can minimize the GHGs emission and improve the SOC.     

No-tillage and conventional tillage effects on durum wheat yield, grain quality and soil moisture content in southern Italy

No-tillage (NT) is becoming increasingly attractive to farmers because it clearly reduces production costs relative to conventional tillage (CT). However, many producers in southern Italy are reluctant to adopt this practice because NT can have contrasting consequences on grain yield depending on weather conditions. The effect of NT and CT on continuous durum wheat (Triticum durum Desf.) under rainfed Mediterranean conditions was studied, over a 3-year period (2000–2002) at two locations (Foggia and Vasto) in southern Italy. Yield, grain quality [thousand kernel weight (TKW), test weight (TW) and protein content (PC)] and soil water content were assessed.Higher yield was obtained with NT than CT in the first 2 years at Foggia. In contrast, mean yield and quality parameters at Vasto were similar for the two treatments, except in the third year in which CT produced more than NT (4.6 Mg ha⁻¹ versus 2.9 Mg ha⁻¹). At Foggia, TW and TKW were higher in NT than CT in all years. Highest PC was obtained under CT (19.6% and 15.5% for CT versus 14.7% and 11.4% for NT, respectively, in the growing season 2000–2001 and 2001–2002) indicating that grain was shriveled with low starch accumulation.At Foggia, where this study was part of a long-term experiment started in 1995, a strong correlation was observed between yield and rainfall during the wheat growing season. The coefficient of determination (R²) values for CT and NT were 0.69^* and 0.31 ns, respectively, and the regression straight line crossed around 300 mm of rainfall. These results indicate that NT was superior below this rainfall value, whereas more rainfall enhanced yield in CT. We conclude that NT performed better at Foggia with limited rainfall during the durum wheat growing season. The superior effect of NT in comparison to CT, was due to lower water evaporation from soil combined with enhanced soil water availability.     

Soil physical properties and wheat root growth as affected by no-tillage and conventional tillage systems in a Mediterranean environment of Chile

No-tillage systems affect soil properties depending on the soil, climate, and the time since its implementation. In heavy no-tilled soils a surface compacted layer is commonly found. Such layer can affect root growth and soil water infiltration. In several cases, surface organic carbon can buffer these problems. The aim of this study was to evaluate the effect of 4- and 7-year-old conventional (CT) and no-tillage (NT) treatments on soil physical properties, root growth, and wheat (Triticum turgidum L. var. durum) yield in an Entic Haploxeroll of Central Chile. In both tillage treatments we study soil water retention, bulk density (ρ_b), soil particle density (ρ_s), soil water infiltration, mean-weight diameter of soil aggregates (MWD), penetration resistance, grain yield, and root length density (L_v) up to a depth of 15 cm. The MWD and the penetration resistance were higher under NT as compared to CT. For the top 5 cm of soil, L_v was greater under NT as compared to CT. Differences of L_v between NT and CT were 2.09, 7.60, and 4.31 cm root cm⁻³ soil during the two leaves, flowering and grain filling phenological stages, respectively. Generally, the effect of NT on these properties was more evident near the soil surface. In contrast, fast drainage macropores, ρ_s, and soil water infiltration rates were higher under CT than under NT. Tillage treatments did not significantly affect ρ_b and yield. A longer time under no-tillage enhanced aggregate stability, however, other soil physical properties were negatively affected.     

Responses by earthworms to reduced tillage in herbicide tolerant maize and Bt maize cropping systems

Genetically modified (GM) crops may affect earthworms either directly through the plant, its root exudates and litter, or indirectly through the agricultural management changes that are associated with GM plant production. In order to investigate such possible effects, we established two field studies of Bacillus thuringiensis (Bt) maize and a glufosinate ammonium tolerant maize and included a reduced tillage (RT) treatment and a conventional tillage (CT) treatment as examples of a likely concomitant change in the agricultural practise. At a French study site at Varois, (Bourgogne), a field grown with the Bt-toxin producing transgenic maize line MON810 was studied for 1 year. At a Danish study site, Foulum (Jutland), 1 year of Bt maize was followed by 2 years of herbicide tolerant (HT) maize. At the French study site, the most prominent effects observed were due to the tillage method where RT significantly reduced the earthworm populations to levels about half of CT. At the Danish study site effects of CT complied with known reduction of anecic earthworms due to this technique and likewise effects of RT were observed for endogeic earthworms. Earthworm populations were diminished with the HT crop, probably due to exposure to the herbicide Basta^® during the two consecutive autumn seasons. This study confirms the importance of including the tillage techniques and pesticide usage when evaluating the environmental effects of new agricultural technologies.     

一膜两年覆盖条件下耕作方法对旱作玉米产量及土壤物理性状的影响

为了优化全膜双垄沟播玉米土壤耕作技术,实现土壤质量保育和增产增效,布设田间定位试验,比较研究了一膜两年全膜双垄覆盖条件下,少免耕对玉米产量、水分利用效率(WUE)、经济效益及土壤物理性状的影响。结果表明:一膜两年用条件下,深松耕—免耕较对照能显著提高玉米的籽粒产量、水分利用效率、收获指数、总产值及产投比,其籽粒产量、水分利用效率、收获指数、总产值及产投比分别较对照提高22.8%,22.0%,15.0%,17.4%,17.4%;深松耕—免耕具有降低表层土壤容重、紧实度,增加土壤总孔度、大团聚体含量及饱和导水率的作用,全膜双垄沟播玉米采用深松耕—免耕具有明显的稳增产增效及土壤结构改善的作用,建议在全膜双垄沟播玉米种植体系中推广应用。     

小麦/玉米间作根系相互作用对氮素吸收和土壤硝态氮含量的影响

通过在甘肃河西灌区的田间试验,该文探讨了地下部分隔作用对小麦/玉米间作氮素吸收和土壤硝态氮含量的影响。研究结果表明：小麦/玉米间作,间作小麦和间作玉米吸氮量在没有地下部分隔条件下都高于分隔。小麦收获后,间作小麦地下部分隔与没有地下部分隔之间土壤硝态氮累积量接近;间作玉米不分隔土壤硝态氮含量和累积量高于分隔。玉米收获后,小麦不分隔土壤硝态氮累积量低于分隔,间作玉米不分隔土壤硝态氮含量和累积量都高于分隔。小麦/空带和玉米/空带间作时,作物氮素吸收和土壤硝态氮含量都没差异。     

残茬覆盖与耕作方式对土壤性状及夏玉米水分利用效率的影响

采用田间和小面积模拟降水试验的方法,对小麦机械收获后残茬覆盖与不覆盖两种条件下免耕、翻耕和间隔深松3种土壤耕作方式夏玉米田的土壤物理性状和水分利用效率进行了研究。结果表明,残茬覆盖与深松相结合,可平衡和改善耕层土壤温度状况,在土壤温度较低时具有保温作用,在土壤温度较高时具有降温作用;可以增加土壤的蓄水和保水能力,模拟降水后24 h测定1 m土层含水量比免耕不盖多26.1 mm,全生育期平均耕层土壤含水量比免耕不覆盖高9.37%;土壤通透性也得到改善;最终水分利用效率比免耕不盖提高25.26%。     

Maize (Zea mays L.) yield and soil properties as affected by no tillage in the black soils of China

A four-year tillage experiment on maize was conducted in the high latitude region of Northeast of China. The main objective of this study was to investigate the effects of different field tillage practices on maize grain yield, soil physical properties, and soil water and temperature dynamics in Northeast of China. The tillage practices included moldboard plow tillage (MOT), rotary tillage (ROT), reduced tillage (RET), combined tillage (COT), and no tillage (NOT). The surface soil water content at depths of 0–20 cm was higher under NOT compared with other tillage practices, but not different at the deeper soil depths in 2011. The soil temperatures under NOT and RET were lower than those under moldboard plow tillage and ROT at depths of 5 and 15 cm, respectively, measured at 9:00 am in 2005. From the hourly dynamics of soil temperature, the differences among the tillage practices mainly appeared during the daytime (from 8:00 am to 7:00 pm). Among all the practices, the average daily soil temperature under ROT was the highest, while that under NOT was the lowest. MOT, ROT, and RET had higher soil accumulative infiltration compared with NOT and COT. The surface soil bulk density under NOT was higher than or equal to that under the other four tillage practices. The maize yields under NOT were the lowest among all the tillage practices for three years straight. Meanwhile, the yields under MOT were the highest, which were about 47%, 61%, and 38% higher than those under NOT. NOT practice is not recommended for use in spring-planted maize under the high latitude humid cool climate Mollisol region in Northeast of China.     

Changes in the weed communities as affected by different primary soil tillage and deep loosening

Long-term soil cultivation at the same depth affects soil characteristics and crop productivity. The aim of the study was to investigate the impact of a long-term different intensity soil tillage methods and deep loosening on weed number, weed agrobiological group and soil seed bank changes in till Bathygleyic Dystric Glossic Retisol soil under the climatic conditions of the Western Lithuania (geographical coordinates 55°43′38″N, 21°27′43″E). The study included different soil tillage methods (conventional ploughing, shallow ploughing and shallow ploughless tillage) and deep loosening. During investigational years, the greatest weed number in crops and the greatest weed seed number in the seed bank were determined in the soil reduced tillage (shallow ploughing and shallow ploughless tillage). The weed number in crops of conventional ploughing soil was 35.8% lover compared to reduced tillage soil. The weed seed number in the seed bank of conventional ploughing was 49.6% lover compared to reduced tillage Decreasing soil tillage intensity resulted in weed seeds concentration in the upper topsoil. A one-time deep loosening had a significant effect during the crop rotation: the weed number in crops and weed seed number in the seed bank were determined to have increased by 26.6% and 51.6% in conventional ploughing soil and by 11.9% and 23.2% shallow ploughless soil respectively. However, after deep loosening, the number of Poa annua in crops decreased 2.9 times in plots of conventional ploughing and 1.7 times – in plots of shallow ploughing soil.     

Soil compressibility and penetrability of an Oxisol from southern Brazil, as affected by long-term tillage systems

The precompression stress value defines the transition from the reloading curve to the virgin compression line in the stress–strain curve, which can be used to quantify the highest load or the most intense predrying previously applied to the soil. Thus, in soils with well-defined structured soil horizons, each layer can be characterized by such mechanical strength. Penetration resistance measurements, on the other hand, can be used to determine total soil strength profiles in the field. The effect of long-term tillage systems on physical and mechanical properties was determined in undisturbed and remolded samples collected at 5 and 15 cm depth, 6 months after applying no-till (NT), chisel plow (CP), and conventional tillage (CT) treatments, along with the application of mineral fertilizer and poultry litter. The compressibility tests were performed under confined conditions, with normal loads varying from 10 to 400 kPa after a defined predrying to −6 or −30 kPa. Penetration resistance was determined in the field, after seeding, in three positions: seeding row (SR), untrafficked interrow (UI), and recently trafficked interrow (TI). No-till system showed greater soil resistance to deformation than tilled treatments, as determined by the higher precompression stress and lower coefficient of compressibility. When original soil structure was destroyed (remolded samples), smaller differences were found. The application of extra organic matter (poultry litter) resulted in a reduction of precompression stress in undisturbed samples. Penetration resistance profiles showed greater differences among tillage treatments in the upper layer of the untrafficked interrow, where NT system showed the higher values. Smaller differences were found in the seeding row (with lower values) and in recently trafficked interrow (with higher values), showing that even traffic with a light tractor after soil tillage reduced drastically the effect of previous tillage by loosening up the soil. On the other hand, the tool used to cut the soil and to open the furrow for seeding, incorporated in the direct seeding machine, was sufficient to realleviate surface soil compaction.