Influence Of Tillage On Soil Aeration

Air- porosity of soil can be altered by tillage. Therefore, it plays a significant role in protecting plants against deficient aeration during critical periods of their life cycle. The effect of five tillage treatments (mouldboard, cultivator, rotary tiller, wedge and zero tillage) and three mulch treatments (paddy straw, rice husk and bare) on the soil oxygen diffusion rate (ODR) during the various growth phases of peanut crop ( Arachis Hypogaea L.) were investigated on a lateritic sandy loam soil (utilsol). These experiments were conducted for two consecutive seasons. ODR values were higher in tilled plots. Among tillage treatments, the highest ODR was recorded under mouldboard (60.51 × 10^-8 g cm^-2 min^-1), followed closely by cultivator (57.65 × 10^-8g cm^-2 min^-1), and it was lowest under rotary tiller (46.29 × 10^-8 g cm^-2 min^-1). During the later growth stages and also in lower soil depths, the differences between the values of ODR narrowed down. Among mulch treatments, plots with rice husk (53.98 × 10^-8 g cm^-2 min^-1), had the higher ODR values. Bulk density was lower, whereas total and aeration porosity were higher, under mouldboard and cultivator. Soil temperatures were also higher under mouldboard and cultivator tilled plots.     

Soil compaction and water table effects on soil aeration and corn growth in a greenhouse study

A greenhouse experiment was conducted to study the effects of aeration on growth of corn seedlings. Variable aeration regimes were created by a combination of 3 levels of soil compaction (1.20, 1.37 and 1.56 Mg m⁻³) and 3 water table depths (10-cm, 20-cm and 30-cm). Soil aeration was assessed by measuring the oxygen diffusion rate (ODR) and the gaseous composition of soil air. Samples of soil air were analyzed for concentrations of oxygen, carbon dioxide, ethylene and nitrous oxide.The ODR decreased with increasing soil compaction. The average ODR for the 30 cm water table was 193.5, 89.2 and 15.4 μg O₂ m⁻² s⁻¹ for the three compaction treatments of 1.2, 1.37 and 1.56 Mg m⁻³, respectively. At 40 days after planting, concentration of carbon dioxide in soil air was as high as 0.5% by volume. High concentrations of ethylene and nitrous oxide were also measured in those samples that contained high levels of carbon dioxide. The range of concentration was 2–19 ppm for ethylene and 2–20 ppm for nitrous oxide.The vegetative growth of corn seedlings, as measured by root and shoot weights and plant height, was not significantly affected by the treatments imposed. However, stomatal conductance and photosynthesis significantly differed among treatments.     

竖管通气对覆盖栽培雷竹生长的影响

探究竖管通气对覆盖栽培条件下雷竹生长的影响,为雷竹林集约化经营提供更为科学合理的技术。本试验共设置4个处理:不覆盖不通气(CK)、不覆盖通气(A)、覆盖不通气(M)、覆盖通气(MA),分析各处理的土壤氧气浓度、土壤矿质元素以及雷竹根系活力、光合参数等指标,探究通气对集约经营雷竹林生长及立地条件的影响。与不覆盖处理(CK)相比,覆盖处理(M)显著增加了土壤表层的有机质、全氮、全磷等的含量,而覆盖加通气处理(MA)则促进了土壤有机质、全氮、全磷等物质的分解;在0～10 cm、10～20 cm、20～30 cm、30～40 cm的各土层中,覆盖通气处理(MA)下的土壤氧气含量比覆盖处理(M)分别提高了：26.19%、28.36%、30.77%、26.92%(P<0.05)。MA处理下的雷竹根系活力比M处理增加了57.16%(P<0.05),叶片净光合速率增加了49.47%(P<0.05)。竖管通气显著改善了雷竹林因长期覆盖经营而引起的土壤缺氧、雷竹根系生长不良、净光合速率降低等问题。     

优化施肥处理下设施菜地土壤容重与孔隙度的变化

土壤容重与孔隙度影响土壤养分的有效性及作物生长,与耕作、施肥、灌溉等农业管理措施密切相关。为了研究设施农业条件下土壤环境质量的变化,探索较优施肥模式。以寿光种植番茄的大棚土壤为对象,以不施化肥和有机肥的土壤为对照,研究优化施肥条件下土壤容重、孔隙度与土壤呼吸强度的变化。结果表明：与对照相比,优化施肥处理在一定程度上改善了土壤容重和孔隙状况,可减少土壤容重3.73%~14.93%,增加土壤总孔度的4.18%~15.79%,平均毛管孔度和非毛管孔度分别增加了8.07%与8.94%。根区与非根区的土壤呼吸强度比对照分别增强了23.4%~34.6%和9.6%~106.9%。其中,以有机肥8 t/hm2和秸秆4 t/hm2混匀撒施、生长期追施氮150 kg/hm2的处理变化最为明显,可在生产实践中推荐运用。试验还表明,根区土壤的平均呼吸强度为62.91 mg/kg?d,约为非根区34.45 mg/kg?d的1.8倍。土壤呼吸强度均与土壤容重和土壤总孔度呈抛物线型变化关系,当土壤容重约为1.25 g/cm3和总孔度约为53%时,土壤具有较强的呼吸作用强度。     

深圳城市绿地土壤孔隙状况与水分特征研究

为了了解深受人为活动强烈影响的城市绿地的土壤物理特性,为充分发挥其增进植物生长、涵养水源和保护城市生态环境等功能提供管理依据,以深圳城市绿地土壤为研究对象,调查分析了土壤容重、孔隙状况、土壤水分常数和水分入渗特征等物理特性。结果表明：深圳城市绿地土壤的容重较高,平均值为1.56 g/cm3。土壤总孔隙度、毛管孔隙度、通气孔隙度较小,平均值分别为41.06%、39.78%、1.27%。土壤水分入渗率变幅很大,土壤初始入渗率为0~8.47 mm/min,稳定入渗率为0~5.90 mm/min。城市公园绿地、道路绿地土壤的容重显著高于城郊菜地土壤,而土壤孔隙度、最大持水量、毛管持水量和田间持水量显著低于城郊菜地土壤;表层0~10 cm的土壤容重、最大持水量、毛管持水量和田间持水量显著低于10~20 cm土壤,土壤孔隙度显著高于10~20 cm土壤。城市绿地土壤容重与孔隙度、田间持水量、最大持水量、初始入渗率及稳定入渗率均呈显著的负相关。     

通气对土壤肥力质量影响的研究进展

肥力是土壤的基本属性,土壤肥力质量及其影响因素研究对农业高产、稳产具有重要意义。土壤“通气”状况,是影响土壤肥力质量的四大因素之一,越来越受到研究者重视。笔者介绍了土壤肥力质量评价指标和通气指标;通气协调土壤水、肥、热状况,控制土壤有机质的分解速度和分解产物,促进作物高产;通气方法包括物理加气、机械加气、化学加气、文丘里管加气和移动式地下滴灌加气;已有研究结果表明通气提高作物产量和品质,其机理是促进作物地上部光合作用及光合产物的积累运转、促进根系生长发育及对土壤矿质元素吸收和增加土壤微生物群落多样性及酶活性;今后需进一步研发性能优良、实用性强的加气设备,从盆栽、微区研究扩展至农田,服务于农业生产。     

土壤紧实度对花生根系生长和活性变化的影响

为探究不同土壤紧实度对花生根系生长和活性变化的影响,确定花生生长所需的适宜紧实度,为花生高产新品种的选育和栽培提供理论依据。以高产花生品种青花7号为试材,采用桶栽的方法,设置土壤容重分别为1.1,1.2,1.3,1.4,1.5 g/cm35个处理,研究了土壤紧实度对花生根系生长和活性的影响。结果表明,在花生根系发展期土壤容重过大不利于根系伸长和表面积扩大,且随着生育进程的推进影响越大,在花生根系衰退期土壤容重过小根系长度和表面积衰退过快,而适宜的土壤容重(1.2 g/cm3)则既能保证根系发展期根系的伸长和表面积扩大,又能延缓根系衰退期根系长度和和表面积的衰退。土壤容重过大或过小均不利于花生根系干物重积累、根系体积增加和根系活力提高,根系直径随着土壤容重的增大而增大。认为容重为1.2~1.3 g/cm3有利于花生根系生长和活性提高。     

不同干扰对城市绿化用地土壤物理性质的影响

为了解压实对城市新建绿地土壤物理性质的影响,以西安植物园新园区为研究对象,依据土壤压实程度的不同以及地表植被的差异进行区域划分,对不同区域内的土壤分层采样,并进行土壤容重、孔隙状况、水分常数等物理性质的测定。结果表明：随着压实程度的增加,土壤各层次间的发生规律发生了改变,土壤出现退化现象。研究区域内的土壤容重偏高,平均值为1.52 g/cm³;土壤总孔隙度、通气孔隙度、土壤含水量、田间持水量、土壤饱和导水率明显偏低,平均值分别为44.71%、12.81%、15.46%、20.77%、20.7 mm/h。土壤容重与总孔隙度、通气孔隙度、田间持水量、自然含水量、饱和导水率之间呈极显著的负相关;通气孔隙度与饱和导水率、自然含水量、田间持水量之间均呈现显著的正相关。压实对各层土壤物理性质的影响表现为表层土>浅层土>深层土,人为践踏产生的压实只影响到表层土壤。     

增施生物有机肥对水稻产量和土壤肥力的影响

采用田间小区试验,研究生物有机肥对水稻生长、碳氮代谢、水稻产量和土壤肥力的影响。结果表明：增施生物有机肥,能够促进水稻的生长,增加农艺性状和生物量,增强碳氮代谢能力,提高根系活力,增加水稻产量,提高耕地肥力;生物有机肥含有大量的有机质和功能微生物,能够使土壤容重降低,土壤中细菌、真菌、放线菌数量增加;土壤容重与微生物群落数量呈极显著负相关,与细菌、真菌、放线菌的相关系数分别为-0.96、-0.94、-0.97;土壤有机质含量与微生物群落数量呈显著正相关,与细菌、真菌、放线菌的相关系数分别为0.83、0.90、0.85;土壤有机质含量与水稻产量呈显著正相关,相关系数为0.85。     

土壤调理剂对连作切花菊品质和土壤性质的影响

种植切花菊的土壤随着年限的不断增加理化性质发生改变、病虫害加重,影响切花菊的生产数量和品质。本研究针对切花菊土壤连作问题进行温室盆栽试验,采用连续种植切花菊6年并表现出严重连作障碍的土壤为盆栽用土,利用天然沸石、竹酢液、香叶天竺葵和海藻粉之间的不同配比,研究施入6种土壤调理剂后对连作切花菊的品质产量和土壤理化性质的影响。结果表明：施用调理剂后,土壤容重和土壤水吸力降低,总孔隙度、毛管孔隙度和通气孔隙度增加,土壤的pH值和EC值降低;切花菊中氮和磷的含量上升,钾含量下降,生物量、株高、叶绿素含量和根系活力都得到一定程度的提高,其中,处理5%沸石+香叶天竺葵（稀释300倍）效果最好。试验为未来解决土壤连作问题提供理论依据和实践支持。     

土壤容重对高产玉米根系生长的影响及调控研究

不同土壤容重不同,其稳定性也不同。土壤容重的变化会引起土壤调节水、气、热能力的变化,提高土壤的自动调节能力可以使土壤肥力水平得以提高并满足植物对生长因子的持续需求。为研究土壤物理性质对玉米高产稳产的影响机理,以耕地棕壤为试验材料,采用盆栽方法,研究不同容重对玉米根系生长指标的影响,并进一步研究了施用不同有机肥量及模拟不同耕作深度对玉米根系生长的调控效果。结果表明:在设计容重范围内,容重增加,根系生长指标都表现为下降,容重大于1.2 g/m3时,不同处理根系生长指标差异显著;当容重大于1.3 g/cm3时,不同处理根系活力差异显著。施用有机肥对高容重土壤调控效果更好,有机质含量为4%与5%的处理差异减小,低容重土壤在所设计的有机质水平内调控效果也都较好。耕层厚度增加可以提高根系生长参数,但与对照相比,差异不显著。所以,对于紧实结构性较差的土壤,改善其调节能力应该通过增施有机肥的方法,紧实结构较好的土壤考虑使用耕翻的办法。     

西南黄壤坡耕地保护性耕作的土壤结构效应

设置两种保护性耕作措施,通过6a持续试验,研究了保护性耕作措施对黄壤结构性状的影响,为西南黄壤地区保护性耕作技术应用与发展提供理论依据。[方法]分别用环刀法、干湿筛法测定土壤容重和土壤团聚体组成,土壤机械组成采用MS2000激光粒度分析仪测定,并计算出土壤孔隙度和团聚体破坏率。 [结果]结果表明：(1)垄播沟覆轮耕与免耕秸秆覆盖两种保护性耕作措施均可降低黄壤容重,增加土壤孔隙,且此作用是由表及里的渐进过程,垄播沟覆措施的土壤容重优化作用要优于免耕覆盖,而免耕覆盖对较深层次土壤孔隙状况优化效果更显著。(2)保护性耕作可提高0～20 cm土壤＞0.25mm干筛团聚体含量,水稳性团聚体含量处理之间差异不显著,但0～20cm层含量略大于20～40cm层。(3)保护性耕作可提高土壤团聚体稳定性,降低团聚体破坏率,免耕覆盖措施对提高土壤团聚体稳定性具有更加显著的效果。[结论]该试验证明了保护性耕作对黄壤土容重、孔隙、团聚体等结构性状有一定的改善作用,这种改善作用是一个非常漫长的由表及里的渐进过程,为西南黄壤地区保护性耕作技术应用与发展奠定了坚实的基础。     

水稻根际含氧量对根系生长的影响

以多个水稻品种为材料, 采用营养液培养试验, 通过气泵增加水稻根际的含氧量, 研究水稻根际含氧量与根系生长的关系。结果表明, 在水稻生长过程中, 抽穗期根系吸收氧气的能力最强, 需氧量最大。根际含氧量对水稻根系形态与分布有影响, 增氧显著增加根长, 提高根系自根基到根尖10~20 cm、＞20 cm部分所占的生物量比例, 同时减少根数; 而在缺氧环境下生长的水稻根数增多, 根长缩短。氧溶量对水稻根系活力的影响存在品种间差异, 提高水稻根际的氧溶量, 杂交稻汕优63和国稻1号齐穗期根系的活跃吸收面积和根系活力显著增加; 根系活力较高的常规籼稻湘早籼11和甬粳18在充氧处理中的根系活力也明显提高, 但根际氧含量的增加对根系活力较低的水稻品种湘早籼24和春江06的根系活力并无明显作用; 缺氧环境下生长的水稻根系的活力降低。     

长期间作及免耕对土壤物理性状及作物产量的影响

针对西北绿洲灌区长期传统覆膜耕作造成土壤结构的稳定性下降、地膜残留过多和土壤质量下降等问题,研究覆膜免耕与禾豆间作种植模式对土壤物理性质和作物产量的影响,以期为试区优化耕作方式和作物种植模式提供理论支撑。田间试验于2013—2020年在河西绿洲灌区进行,设置传统耕作覆膜(CT)、覆膜免耕(NT) 2种耕作措施;单作豌豆(P)、单作玉米(M)、玉米间作豌豆(M//P) 3种种植模式,2019年和2020年玉米收获后测定土壤物理性状和作物产量等相关指标。结果表明：（1）0～30 cm土层≥0.25 mm水稳性团聚体含量、平均重量直径(MWD)、土壤容重和土壤总孔隙度在NT与CT处理间存显著差异,NT较CT≥0.25 mm水稳性团聚体含量提高2.02%～7.76%、MWD提高19.4%～26.0%、土壤容重降低1.31%～1.57%、总孔隙度增加1.97%～2.28%;(2)NT处理下,不同种植模式间存在显著差异,M//P分别较P和M处理水稳性大团聚体含量增加12.60%～20.11%和7.05%～11.55%,MWD分别较P和M处理增加9.61%～12.44%和4.01%～8.01%,土壤...     

种植翻压紫云英配施化肥对稻田土壤理化性状和水稻产量的影响

为探讨稻田在翻压等量紫云英作绿肥的情况下化肥减量施用对土壤可持续生产能力的影响,依托长期种植紫云英定位试验,以不施肥(CK)为对照,研究化肥(100%F)、紫云英配施100%、80%、60%和40%化肥(MV+100%F、MV+80%F、MV+60%F、MV+40%F)对水稻收获期土壤容重、土壤总孔隙度、土壤毛管孔隙度、土壤养分、水稻产量及产量性状的影响。结果表明：与对照不施肥相比,紫云英配施减量化肥能显著降低土壤容重,提高土壤总孔隙度;紫云英配施化肥可显著提高土壤毛管孔隙度。翻压紫云英可以替代20%~40%氮肥;与单施化肥(100%F)和紫云英配施化肥(MV+100%F)相比,紫云英配施减量20%~60%化肥可显著降低土壤有效磷含量;与对照不施肥相比,紫云英配施化肥可显著降低土壤速效钾含量,降幅为5.5%~17.8%,并可显著提高土壤有机质含量,增幅为15.0%~26.0%。单施化肥(100%F)、紫云英配施100%、80%、60%和40%化肥水稻产量较对照不施肥提高30.0%~39.6%,以紫云英配施80%化肥水稻产量最高。紫云英配施减量20%~40%化肥水稻产量较配施化肥100%增加2.7%~7.1%。分析产量主要构成发现,紫云英配施化肥主要是通过增加有效穗来提高产量。综合考虑土壤理化性状、水稻产量等水稻可持续发展因素,豫南稻区紫云英翻压量22500 kg/hm²时,化肥减施20%~40%均可在此地推广,以化肥减施20%为最优。     

滨海盐渍土改良剂的筛选及应用效果研究

针对天津滨海盐渍土结构性差、土壤养分匮乏、脱盐碱化现象严重等问题,进行了改良剂改良滨海盐渍土的试验研究。盆栽试验通过综合分析土壤含盐量、土壤养分含量、黑麦草长势情况,筛选出效果最佳改良剂配方。野外应用效果试验进一步表明,施用改良剂能抑制土壤脱盐碱化,提高土壤养分含量、明显改善土壤结构和肥力状况。土壤水解氮、速效磷、速效钾、有机质含量分别提高了123.8%、171.0%、22.0%、37.5%,土壤容重降低了15.54%,土壤总孔隙度增加了19.66%,土壤渗透性提高了127.78%,土壤微结构由面状孔隙转变为复杂堆积型孔隙。改良剂的施用非常利于土壤水肥气热状况的调节,是天津滨海盐渍土适宜的盐碱改良剂。     

Mulching Improves Water Productivity,Yield and Quality of Fine Rice under Water‐saving Rice Production Systems

Water‐saving rice production systems are inevitable in the wake of severe water shortage in rice‐growing regions of the world. Mulches can improve water productivity, yield and quality of rice through increase in water retention. Studies were conducted for two consecutive years to assess the potential role of mulches (plastic and straw) in improving the performance of water‐saving rice production systems in comparison with no mulch used and conventionally irrigated transplanted rice. Water‐saving rice production systems in this study comprise aerobic rice and transplanted rice with intermittent irrigation. These systems saved water (18–27 %) with improved water productivity more than the conventional system. However, these systems caused a yield penalty of 22–37 %; nevertheless, these yield losses were compensated with the application of mulches under water‐saving rice production systems. Both plastic and straw mulches were helpful in improving moisture retention and water productivity (0.18–0.25 kg grain m^?3 water) relative to non‐mulch treatments (0.19–0.29 kg grain m^?3 water). Mulch application was also helpful in reducing the number of non‐productive tillers and sterile spikelets, and improving the productive tillers, kernel number and size, and kernel quality. Plastic mulch was more effective than straw mulch in improving water retention, water productivity and reducing spikelet sterility. In conclusion, the mulching improved the soil moisture retention, and thus enhanced the rice water productivity, spikelet fertility, paddy yield and quality of rice. This signifies the importance of mulching in water‐saving rice production systems.     

Effects of Reduced Tillage and Fertilization Practices on Soil Characteristics, Plant Water Status, Growth and Yield of Upland Cotton

Three different tillage practices, conventional (mouldboard ploughing at 22–25 cm plus one rotary hoeing at 5–6 cm, CT), minimum (one rotary hoeing at 12–15 cm, MT), and no‐tillage (direct drilling in soil covered by vetch residues, NT), combined with three fertilization treatments, inorganic (50 kg N ha^?1 as ammonium sulphate), cattle manuring (30 t ha^?1), and control (no‐fertilizer), were applied on a cotton crop (Gossypium hirsutum L. cv. Acala SJ‐2) grown on a clay loam soil in the field of the Agricultural University of Athens. Soil (gravimetric water content, bulk density, and penetration resistance in the top 40 cm) and plant parameters (root growth, leaf water potential, leaf area growth and seedcotton yield) were recorded throughout the cultivation period in all treatments. No‐tillage was associated with significantly higher values of soil water throughout the observation period caused by the vetch mulch. Bulk density and penetration resistance were initially higher in the no‐tilled plots, but they became significantly lower after 2–3 months from sowing. These beneficial effects on soil properties favoured root growth, expressed as root surface density, in the NT‐plots at the top soil layer. Similar, although less spectacular, effects were observed in the manured plots. Plant water status, expressed in terms of the water potential index, was significantly and consistently best in the NT‐ and worst in the CT‐plots throughout crop growth. In addition, NT favoured a better foliage growth and resulted in significantly higher yields than the other tillage practices. In general, NT, and in second instance, MT considerably improved plant water status, and hence foliage growth and yield in comparison with CT by maintaining higher levels of soil water and improving root growth. Manuring positively interacted with the reduced tillage practices for most soil and plant parameters.     

Drainage and tillage effects on a crosby-kokomo soil association in Ohio IV. Soil physical properties

Bulk density, soil structure, penetrometer resistance, and moisture retention characteristics were examined for the Crosby-Kokomo Association near Columbus, Ohio. The soils are classified as fine mixed, mesic, Aeric Ochraqualf and fine, mixed, mesic, Typic Argiaquoll, respectively. Effects of four tillage methods were studied with and without subsurface drainage. Tillage methods were: no-till, raised beds, ridge till and moldboard plow. The tillage treatments were laid out according to a Randomized Block Design with three replicates on each drainage site.Soil samples obtained in August, 1987 to 50 cm depth in 10 cm increments, were analyzed for aggregate size distribution, and moisture retention characteristics. In addition, surface (0–10 cm and 10–20 cm depths) core samples were obtained in July 1989 for measurement of soil bulk density, and moisture retention characteristics. Penetrometer resistance and soil moisture content for the surface layers were also measured in July 1989.The mean weight diameter (MWD) was higher for undrained than drained treatment, 2.94 mm vs. 2.49 mm, respectively. Neither drainage nor tillage treatments had a significant effect on soil bulk density measured about 8 weeks after sowing. Penetrometer resistance was lower, and surface soil moisture content was higher in the undrained compared with the drained treatment. Soil moisture retention at all suctions and plant-available soil moisture reserves were more in undrained than drained soil. Differences in soil moisture retention among drainage treatments are attributed more to organic matter induced differences in pore size distribution than to total porosity. For these soils in central Ohio, drainage had a more significant effect on soil physical properties than tillage operations performed in the fall and/or spring.     

连续增氧对不同基因型水稻分蘖期生长和氮代谢酶活性的影响

为明确氧对不同基因型水稻生长和氮素代谢的作用机理,以籼稻、粳稻和旱稻品种为材料,采用营养液培养,考察根际连续增氧水稻分蘖期生长和氮代谢状况。结果表明,连续增氧后,各水稻品种叶绿素含量均有所下降,国稻1号(籼稻)地上部分和根系干物质重分别降低44%和40%,巴西陆稻(旱稻)和秀水09 (粳稻)降低不显著。国稻1号和巴西陆稻的氮积累量分别降低35.8%和36.0%。各基因型水稻叶片NRA (硝酸还原酶活性)显著提高,GSA (谷酰胺合成酶活性)下降。秀水09,叶片NRA增加较少(P>0.05)。连续增氧提高了水稻根比表面积和氧化强度;但降低了叶片叶绿素含量和GSA,不利于水稻氮素吸收和干物质积累。不同基因型水稻对连续增氧的响应存在差异。