不同程度压实对土壤理化性状及作物生育产量的影响

采用大、小四轮式拖拉机在冬小麦播种地上压地1到10遍，对照为未压实地，测定对小麦生育产量影响；同时进行了不同程度土壤压实后孔隙度为58%，52%，46%和40%的土壤理化性状测定试验。结果表明不同程度压实具有系统累积效应，为免耕、保护性耕作和减免中耕提供了运用依据。     

小型拖拉机土壤压实的有限元预测

农业土壤的基本特征是松软和经常处于非饱和状态，土壤体积密度与含水率既是主要参数又是影响压实的重要因素，且在不断地变化。为了进行有效田间土壤压实管理，根据具体土壤特性，采用一个二维的模型，用有限元方法进行土壤压实预测。模型考虑了应力路径、初始土壤体积密度和含水率等，将土壤体积密度视为平均主应力和最大自然剪切应变的非线性函数，可预测小型拖拉机在非饱和土壤上通过时引起土壤体积密度的变化及应力分布情况等。在华北轻壤土的试验证明，模型具有良好的拟合效果。     

地形和土壤属性对大豆产量的影响

正确理解作物产量的变异性特征及其影响因素是对农田地块进行科学管理的基础。地块的地形特征是导致作物产量变异形成的主要因素。本文选择代表不同地形特征的洼地农田和岗地农田为研究对象,分析地形对土壤属性和大豆产量的影响以及它们之间的相互关系。研究结果显示,洼地农田与岗地农田的土壤属性和大豆产量均存在显著性差异(P<0.05)。洼地农田的土壤养分含量较高,但土壤结构较差,其平均重量直径(MWD)和几何平均直径(GMD)显著小于岗地农田,质量分形维数(Dm)显著大于岗地农田;在两类农田地块中,大豆产量的差别较大,洼地农田的大豆产量仅为岗地农田的62%。相关性分析表明,大豆产量与土壤结构稳定性和地块高程呈极显著正相关(P<0.01);土壤有机碳和土壤养分对大豆产量没有显著影响。     

割草机对苜蓿地土壤压实的试验研究

用纽荷兰HW320自走式割草压扁机压地1～10次,测定不同压实次数、不同深度土壤体积密度、硬度、孔隙度、三相比、透水性等指标的变化及其每次压实后苜蓿产量的变化。结果表明：割草机压实对苜蓿地土壤结构参数影响显著;碾压次数越多,影响程度越大;割草机主要使0～30 cm土层的土壤结构产生压实;对透水性影响最为敏感;压实导致苜蓿减产,10次压实使每公顷苜蓿年损失干草4464 kg。     

轮式和履带式车辆行走对农田土壤的压实作用分析

由履带式行走机构代替轮胎被认为是减缓大型农业车辆对土壤压实的有效手段之一。与轮胎相比,履带具有更大的接地面积,能够有效减小车辆对土壤的平均压力。然而履带与土壤接触面间的应力分布极不均匀,应力主要集中在各承重轮下方,履带减缓土壤压实的能力是目前有待研究的问题。该研究通过在土壤内埋设压力传感器,测试比较了相近载质量的轮胎和履带式车辆作用下,0.15和0.35 m深度土壤内的最大垂直及水平应力,同时研究了车辆行驶速度对土壤内垂直及水平应力大小的影响。基于土壤压实分析模型计算了轮胎和履带压实的0.1～0.7m深度土壤内的最大垂直及水平应力分布。通过对0.15和0.35 m深度的土样进行室内测试,比较了轮胎和履带式车辆压实对土壤透气率、先期固结压力及干容重大小的影响。结果表明,履带相比较于轮胎,能够减小土壤内的垂直及水平应力,但垂直应力的减小量比水平应力大;轮胎对0.15和0.35m深度土壤作用的平均最大垂直应力分别约为履带的2.2及2.0倍,而平均最大水平应力仅分别约为履带的1.2及1.1倍。轮胎作用下的最大垂直及水平应力在表层土壤内明显大于履带,但两者的应力差值随着土壤深度的增加逐渐减小,分...     

水平贯入式土壤压实度测试系统及试验研究

针对土壤压实度检测的需求,本研究应用CFBLS-100型拉压传感器和基于PCMCIA总线的DAQP-12数据采集卡,在LabVIEW环境下设计了一套土壤压实度现场测试系统。该系统能够实时显示传感器输出电压及所对应的压力变化曲线,并将所采集到的数据存储到计算机中,完成对数据的分析。经标定试验证明:该测试系统所拟合的方程为线性,其相关系数较高,线性度较好,灵敏度较高,系统精度等级小于1级,工作时系统稳定可靠。由室内试验知,在不同水平分层处,土壤压实度与不同模拟压力间均表现出3次多项式的函数关系,显著性较强(α0.05)。且在不同模拟压力下,不同土壤水平分层处的土壤压实度和土壤容重表现出相似的特性,随着模拟压力的增加和土壤分层逐步加深,土壤压实度和土壤容重的增加趋势趋于一致。为研究作物地下组织与土壤之间的根土系统及合理耕层的构建提供理论基础,并为农业机械的研发具有一定的意义。     

黄淮海旱作区土壤压实度空间分布特征及其影响因素

为探究旱作区农田不同层次土壤压实度特征,基于2017年采集的255个土壤样品,运用Mann-Kendall突变检验法、地统计学和冗余分析等方法,探究黄淮海旱作区耕作层和压实层空间分布特征,分析不同层次的土壤压实度的空间变异特性及影响因素,并提出了最佳土壤压实度范围。研究结果表明:旱作区耕作层和压实层厚度均呈现由北向南递增的趋势,耕作层最大厚度可达22.50 cm,最低仅有10.21 cm;压实层厚度最大可达17.50 cm,最小值也达到7.50 cm。从不同层次来看,耕作层和压实层的压实度具有空间分布一致性,耕作层压实度高值区主要分布在河南省东部、安徽北部及河北北部地区,最大值可达87.68%以上,低值区则主要集中在山东西北部以及河北南部地区。和压实层压实度相比,耕作层压实度是影响粮食产量的主要因素,且在70%～80%时获得较高产量。分析表明,土壤压实度受到年降水量、平均气温、土壤自然属性等环境因子和机械耕作等人为因素综合作用的影响。研究结果可为黄淮海农田土壤压实情况的改善及管理措施的科学制定提供理论支撑。     

深松对土壤特性及玉米产量的影响(英文)

土壤压实和缺水成为制约华北平原作物产量的2个重要因素,为了提高半干旱地区旱地对自然降水的利用率,打破犁底层,达到节约用水、提高作物产量的目的,该文于2011年至2013年,在济宁进行了深松和当地旋耕2种耕作方式对土壤物理性质和玉米产量影响的试验研究。试验采用随机化完全区组设计,并采用方差分析评价不同耕作方式的耕作效果。试验结果表明,除了表层土(0~15 cm),在作物的所有生长时期,深松耕作下的土壤容重和紧实度明显小于旋耕,尤其是玉米吐丝期。另外,在玉米吐丝期,深松下的25~35 cm土层含水量比旋耕高出9.45%(2012年)和8.64%(2013年)。深松能显著提高玉米产量达6.08%~7.23%,但2种耕作方式对玉米的千粒质量影响相差不大。该研究对为华北平原提供一种更可持续的耕作方式—深松耕作具有重要意义。     

土壤紧实度对温室番茄生长发育、产量及品质的影响

试验研究土壤紧实度对日光温室番茄生长发育、产量及品质的影响结果表明 ,随土壤紧实度增大而植株生长发育迟缓 ,产量和品质下降 ,果实风味品质变差。而土壤疏松处理植株生长发育良好 ,座果节位下降 ,水分利用效率提高 ,果实游离氨基酸、可溶性糖和可溶性蛋白质含量增加 ,硝酸盐含量下降 ,果实风味好且产量高 ,经济系数较高。     

鲜桃坚实度和糖度分布差异的实验研究

坚实度和糖度是评价水果成熟程度、果实品质的一个重要指标,桃内各处坚实度和糖度的分布存在一定差异。了解桃内坚实度、糖度存在的差异,将为根据这些指标进行完整水果分级提供指导。实验表明,不同成熟度的桃及同一个桃不同部位（顶部、中部、底部）、测点（沿周向分６点）的坚实度、糖度均存在差异,其中部位和成熟度对指标的影响是显著的,不同测点对指标差异的影响程度也不同。     

Effects of compaction on soil hydraulic properties,penetration resistance and water flow patterns at the soil profile scale

The aim of this study was to quantify the effects of compaction on water flow patterns at the soil profile scale. Control and trafficked plots were established in field trials at two sites. The trafficked treatment was created by four passes track‐by‐track with a three‐axle dumper with a maximum wheel load of 5.8 Mg. One year later, dye‐tracing experiments were performed and several soil mechanical, physical and hydraulic properties were measured to help explain the dye patterns. Penetration resistance was measured to 50 cm depth, with saturated hydraulic conductivity (K_s), bulk density, and macroporosity and mesoporosity being measured on undisturbed soil cores sampled from three depths (10, 30 and 50 cm). Significant effects of the traffic treatment on the structural pore space were found at 30 cm depth for large mesopores (0.3–0.06 mm diameter), but not small mesopores (0.06–0.03 mm) or macroporosity (pores > 0.3 mm). At one of the sites, ponding was observed during the dye‐tracing experiments, especially in the trafficked plots, because of the presence of a compacted layer at plough depth characterized by a larger bulk density and smaller structural porosity and K_s values. Ponding did not induce any preferential transport of the dye solution into the subsoil at this site. In contrast, despite the presence of a compacted layer at 25–30 cm depth, a better developed structural porosity in the subsoil was noted at the other site which allowed preferential flow to reach to at least 1 m depth in both treatments.     

土壤紧实胁迫对黄瓜碳水化合物代谢的影响

用容重分别为1.25 g/cm3(疏松土壤,即对照)和1.55 g/cm3(紧实土壤)的土壤进行盆栽试验,研究了土壤紧实胁迫对“津春4号”黄瓜(Cucumis sativusL.)不同生育期叶片和根系碳水化合物代谢的影响,以探讨土壤紧实胁迫对黄瓜生长产生影响的机理.结果表明,在土壤紧实胁迫条件下,黄瓜不同生育期叶片的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均显著下降,胞间CO2浓度(Ci)显著升高,光合作用受到抑制;叶片中蔗糖磷酸合成酶(SPS)活性显著降低,蔗糖合成酶(SS)、酸性转化酶(AI)和中性转化酶(NI)活性显著增强,蔗糖、葡萄糖、果糖和淀粉含量显著增加,蔗糖的合成与输出受到抑制;不同生育期根系SPS、AI和NI活性显著下降,而SS活性显著增强,蔗糖、葡萄糖和果糖含量显著增加,淀粉含量基本不变.这表明,土壤紧实胁迫抑制了黄瓜叶片中同化物的合成和输出,降低了碳水化合物向根系中的输入,阻碍了根系对碳水化合物的利用,使植株矮小,产量下降.     

Effects of compaction on soil surface water repellency

Water repellency can reduce the infiltration capacity of soils over timescales similar to those of precipitation events. Compaction can also reduce infiltration capacity by decreasing soil hydraulic conductivity, but the effect of compaction on soil water repellency is unknown. This study explores the effect of compaction on the wettability of water repellent soil. Three air‐dry (water content ～4 g 100 g^?1) silt loam samples of contrasting wettability (non‐repellent, strongly and severely water repellent) were homogenized and subjected to various pressures in the range 0–1570 kPa in an odeometer for 24 h. Following removal, sample surface water repellency was reassessed using the water drop penetration time method and surface roughness using white light interferometry. An increase in compaction pressure caused a significant reduction in soil surface water repellency, which in turn increases the soil's initial infiltration capacity. The difference in surface roughness of soils compacted at the lowest and highest pressures was significant (at P > 0.2) suggesting an increase in the contact area between sessile water drops and soil surfaces was providing increased opportunities for surface wetting mechanisms to proceed. This suggests that compaction of a water repellent soil may lead to an increased rate of surface wetting, which is a precursor to successful infiltration of water into bulk soil. Although there may be a reduction in soil conductivity upon compaction, the more rapid initiation of infiltration may, in some circumstances, lead to an overall increase in the proportion of rain or irrigation water infiltrating water repellent soil, rather than contributing to surface run‐off or evaporation.     

土壤紧实胁迫对黄瓜生长、产量及养分吸收的影响

用容重分别为1.2、1.4和1.6.g/cm3的土壤进行盆栽试验,研究了土壤紧实度对黄瓜生长、产量及养分吸收的影响。结果表明,当土壤紧实度增大时,黄瓜秧苗的株高在定植后的15.d后受到显著抑制;第4叶的叶宽和叶长在定植后9～17.d内增加;茎粗则是在稍紧的土壤中(R.1.4)最大,过紧的土壤中(R.1.6)最小;根系伸长生长受阻,干物质质量及活力显著下降,根冠比降低;生物学产量、经济产量、经济系数的变化情况及植株对氮、磷、钾吸收量的变化与茎粗的变化趋势相同。在本试验条件下,容重为1.2.g/cm3的土壤利于株高及根系的生长,容重1.4g/cm3的土壤则利于茎粗、根系养分的吸收及产量的增加。     

Soil compaction effects on soil bulk density and penetration resistance and growth of spring barley (Hordeum vulgare L.)

Abstract

The weight of the tractor is not the only factor affecting soil compaction. Soil-management practices, such as the use of fertilizers and pesticides, also affect soil properties through an increased number of overriding. The aim of the current study was to investigate compaction effects on soil physical properties, such as dry bulk density and penetration resistance, and the growth of spring barley (Hordeum vulgare L.) as a monoculture. The five-year experiment was conducted on the Estonian University of Life Sciences’ research field at Eerika, near Tartu in 2001–2005. The soil of the experimental site is sandy loam Stagnic Luvisol. The treatments included were no compaction, one pass, three passes, and six passes. All passes were track-by-track. Measurements of soil and plant were made in the earing phase of barley and measurements of yield in the maturity phase of barley. The compaction treatment was conducted using an MTZ-82 tractor (total weight 4.84 Mg). Neither fertilizers nor herbicides were used. 5 years after compaction distinguishable subsoil and topsoil compaction was detected. Soil deformation increases with the number of passes; in the case of six passes soil bulk density increased by 0.15 Mg m^?3 and penetration resistance by 3 MPa. However, there were no significant differences in the soil bulk density and penetration resistance between treatments compacted with one and three passes. The effect of compaction on soil bulk density was higher when the soil was compacted under wet conditions. Compaction decreased the quantity of barley shoots, their phytomass, and grain yield by more than 80%. In the second year of the experiment the dry weight of above ground biomass decreased by almost three times and shoots’ density by 1.5 times, compared with the first year results. In the third year of the experiment the biomass, plant density, and grain yield of barley were stabilized and no further decreases were detected in the following two experimental years. The results from the experiment revealed that even a low weight tractor can induce subsoil compaction and a high decrease of plant productivity by repeated passes over time.     

地形对漫川漫岗黑土区大豆产量的影响

为研究黑土区田块尺度地形对大豆产量造成的影响,在海伦东兴合作社具有明显地形起伏的地块,采集大豆田间试验数据,考虑温度、太阳辐射、坡度、土壤养分等因素,运用作物生长模型DSSAT(Decision Support Systemfor Agrotechnology Transfer)模型对各样点进行参数率定及验证,得出以下结论:1)DSSAT模型的模拟产量与实际产量的相对均方根误差为7.9%,模拟结果表现为优,表明运用作物模型模拟不同地形上的产量变异具有可行性;2)地形通过影响作物生长环境因子的时空差异决定产量差异,田块尺度温度、水分和坡度是影响产量差异的主要因素;3)坡顶和坡底的产量相对较高,且产量变异性较小,阳坡虽然接收到更多的光照,却由于水分胁迫造成减产,坡底和平缓坡顶水肥保持较好,易获得高产。研究成果为田间精细管理与田块尺度耕地高效利用提供科学依据。     

模拟机械压实对黑土微团聚体组成及稳定性的影响

采用田间模拟机械压实的方法,通过对不同深度压实土壤水稳性微团聚体组成、平均质量比表面积、分形维数和分散系数等特征指标的测定、计算与分析,研究了机械压实对黑土区耕作土壤微团聚体组成及稳定性的影响。结果表明:0~20 cm表层土壤仅12次压实时平均质量比表面积、分形维数和分散系数显著高于对照(P0.05);20~40 cm亚表层土壤3次压实时平均质量比表面积、分形维数值显著降低,而12次压实时平均质量比表面积、分形维数和分散系数显著增加(P0.05);40~80 cm下层土壤,平均质量比表面积、分形维数和分散系数随压实次数的增加而增大,除3次和6次压实之间外,其他处理间差异均达显著水平(P0.05)。可以认为,压实对黑土区耕作土壤团聚体组成及稳定性的影响表现为下层土壤的积累压实为主。     

Effects on some clay soil qualities following the passage of rubber-tracked and wheeled tractors in central Italy

There is increased use of rubber-tracked tractors for ploughing on clay soil (Vertic Cambisol) in central, south and insular Italy instead of metal-tracked tractors, because they allow travel on public roads. Field tests were carried out on arable soil previously ploughed and harrowed to compare two types of tractors, one rubber-tracked (CAT Challenger Ch 45) and one wheeled (New Holland 8770) in order to establish the compacting effects resulting from 1 and 4 passes of the tractors in the same track. The following parameters were studied: soil penetration resistance, bulk density and its increment ratio, soil shear strength, soil macroporosity and hydraulic conductivity. Multiple passes made by the two tractors induced very similar effects on the soil in regards to soil penetration resistance. Mean values of penetration resistance (0–0.20 m depth) were 1.15 MPa for the rubber-tracked tractor and 1.11 MPa for the wheeled tractor; mean values of penetration resistance (0.21–0.40 m depth) were 1.07 MPa for the rubber-tracked tractor and 1.17 MPa for the wheeled tractor. The decrease in macroporosity, in particular that of elongated pores in the soil surface layer (0–0.10 m depth) was greater in treatments involving the rubber-tracked tractor (from 20.2 to 2.7%) than for the wheeled tractor (from 20.2 to 10.3%). Following traffic of the two tractors, hydraulic conductivity decreased and the following values were found for the five treatments: control, 18.48 mm h⁻¹; wheeled tractor 1 and 4 passes, 11.15 and 7.45 mm h⁻¹, respectively; rubber-tracked tractor 1 and 4 passes, 3.25 and 1.1 mm h⁻¹, respectively. Highly significant correlations between shear strength and dry bulk density, and between hydraulic conductivity and elongated pores and total macroporosity were found. Significant linear relationships between macroporosity and penetration resistance for 1 and 4 passes of both tractors were found in the soil layers (0–0.10 m). A significant difference was found between tractors and for correlations of penetration resistance values above control values. However, in the soil layer (0–0.20 m depth), with respect to the higher degree of macroporosity and low values of penetration resistance, treatments involving wheeled tractor (1 pass) showed a lower degree of soil compaction than was observed after 1 pass of the rubber-tracked tractor.     

微孔深松耕降低土壤紧实度提高棉花产量与种籽品质

长期传统耕作导致土壤紧实形成犁底层是影响农田土壤质量和作物生长的关键障碍因子之一。为解决这一问题,于2013年4月至2014年5月在山西运城南花农场开展为期1 a的大田试验,对比研究微孔深松耕技术和旋耕机旋耕15~20 cm的传统耕作方法对土壤紧实度以及棉籽品质性状和生长发育的影响。结果表明:微孔深松耕技术较传统耕作方式,棉花苗期犁底层40 cm处土壤紧实度由9 069.70降低到558.80 k Pa,吐絮期犁底层40 cm处的土壤紧实度由8 089.70降低到1 174.20 k Pa,吐絮期0~40 cm土层中微孔深松耕土壤容重最大为1.05 g/cm3,传统耕作最大为1.56 g/cm3;在30 cm土层中,微孔深松耕的总根量比传统耕作方式多187.03%;微孔深松耕处理棉株棉铃的5室铃率较传统耕作增加15.00%,每个棉瓤的种子数平均增加1~2粒;棉籽的籽指、密度、绒长均明显增加,脂肪含量显著降低(P0.05),蛋白质含量显著增加(P0.05),单株铃数比传统耕作增加6.34%,铃质量增加5.75%,皮棉产量增加10.12%。效益分析表明,采用微孔穴深松耕作种植棉花,每公顷净收益增加3 338.00元。该研究揭示了微孔深松耕作可有效打破犁底层,具有疏松土壤紧实度,并提高棉籽品质增加棉花产量,为该项技术应用于生产提供试验依据。