冀东滨海平原稻区土壤钾库状况与变化

通过对大面积土壤各形态钾的定位监测,研究了1982～2016年30余年间冀东滨海平原稻区土壤钾库的现状、变化及其影响因素,分析了成土母质、耕种施肥等对该区域土壤钾库的影响。主要结果:(1)冀东滨海平原稻区土壤全钾、缓效钾、速效钾平均含量分别为23.04 g/kg、1 615.94 mg/kg、247.37 mg/kg。种稻40～70余年间,各年限土壤全钾、速效钾分别维持在23.96 g/kg、257.41 mg/kg左右。与种稻40年相比,缓效钾年均减少20.19 mg/kg。(2)不同母质土壤全钾、缓效钾、速效钾含量大小顺序为:海相沉积物、泻湖沉积物河流冲积物;土壤缓效钾/全钾和速效钾/全钾均为海相沉积物、泻湖沉积物河流冲积物,3种母质发育的土壤速效钾/缓效钾差异不显著;海相沉积物、泻湖沉积物二者之间的各形态钾含量及比值均无显著差异。(3)土壤速效钾与土壤盐分、有机质均呈显著正相关关系;土壤速效钾与有效磷无显著相关关系。主要结论:随种植年限增加,土壤全钾、速效钾无显著变化,缓效钾显著下降。海相沉积物、泻湖沉积物发育的土壤全钾、缓效钾、速效钾的含量均显著高于河流冲积物,土壤速效钾与盐分呈显著正相关关系。稻区土壤钾输入量小于水稻钾的输出量,随着种稻年限的增加,逐渐消耗土壤缓效钾。     

四川雨城区主要土壤母质上的耕地土壤性质变异研究

通过在四川省雨城区采集侏罗系沙溪庙组(J2s)、侏罗系遂宁组(J3s)、侏罗系蓬莱镇组(J3p)、白垩系夹关组(K2j)等地层9种母质上发育的耕地土壤样品共55个,并进行土壤性质测定及对比分析,结果表明:白垩系夹关组紫色砂岩上发育的耕地土壤较其他紫色母岩上发育的耕地砂粒含量高,pH低,养分含量低;第三系名山群及白垩系灌口组上发育的耕地土壤具有较其他母质高的土壤全钾;青衣江灰色河流冲积物发育的耕地土壤较其他母质发育的耕地土壤全磷和速效磷含量高,第四系冰水沉积物上发育的耕地土壤pH最低,粘粒含量高,土壤有机质及全氮、速效氮较其他母质发育的耕地土壤高。     

我国著名的土地资源及水土保持专家宋桂琴研究员

宁南地区土壤矿质元素的含量顺序为SiO₂>Al₂O₃>CaO>Fe₂O₃MgO>K₂O>MnO>Zn>Cu,其中硅、铝、铁、钛空间分布较均匀；钙、镁、钾变异较大、空间分布不均匀。硅、钛、铜、锌、锰为残积母质>洪冲积母质>黄土母质；铁、镁、钾为洪冲积母质>残积母质>黄土母质；铝为洪冲积母质>黄土母质>残积母质；钙为黄土母质最高，残积母质很低。从山地洪积扇中上游阶地中下游阶地，硅、铜、锌、锰逐渐减少；铝、镁、铁、钙、钾则不断增加     

宁南山区退耕地不同植被类型对土壤理化性质的影响

对宁南山区典型区域——彭阳中庄小流域3种不同植被类型的土壤物理和化学性质进行了分析测定。结果表明:(1)沙棘林地和人工草地的土壤含水量、土壤容重和土壤孔隙度均小于自然封育,而沙棘林地和人工草地两者相比较而言,0—200cm土层沙棘林地的土壤平均含水量小于人工草地,0—60cm土层土壤容重人工草地相对较小,孔隙度相对较大;(2)0—60cm土层沙棘林地和人工草地的全氮、碱解氮和有机质平均含量与自然封育相比较,其含量由高到低的顺序为:自然封育>人工草地>沙棘林地,且差异显著;而全钾、速效磷、速效钾的平均含量与自然封育相比较,其含量由高到低的顺序为:林地>自然封育>人工草地;全磷平均含量变化依次为:林地>人工草地>自然封育。     

晋西黄土区林草复合界面土壤水分养分分布规律研究

通过对晋西黄土区刺槐林与天然草带的复合界面及其对照（林地、草地）生长季土壤水分和养分（有机质、全氮、速效氮和速效钾）的测定,分析比较了其水分和养分的空间分布特征及其变化规律。结果表明,不同土壤层次的土壤含水量在水平方向上存在差异,在浅层土壤（0-20cm）,土壤含水量从大到小依次为:草地、林地、林草界面,在深层土壤（20-100cm）,土壤含水量从大到小依次为:草地、林草界面、林地;在垂直方向上,随着土层深度的增加,研究区林地、草地、林草界面的土壤含水量表现为逐渐降低的趋势,刺槐林地在60-100cm土层中土壤含水量有少许回升。研究区复合类型内土壤养分分布不均衡,水平方向上有机质平均含量为林草界面<草地<林地;全氮平均含量为林草界面最小,草地与林地相差不大;速效磷平均含量为林地<草地<林草界面;速效钾平均含量为草地<林草界面<林地;垂直方向上,各个生态类型的有机质含量、全氮含量、速效钾含量随着土壤层次的加深逐渐减少,而速效磷含量在土壤的不同层次呈现不同的变化。     

三江源区草地退化与人工恢复对土壤理化性状的影响

以三江源区不同退化程度的天然草地及不同恢复年限的人工草地为研究对象,系统分析土壤理化性质随取样深度的动态变化。结果表明:(1)人工草地土壤含水量及全氮、全钾、全磷、速效钾、速效磷的含量随恢复年限均表现出先减小后增大的"V"形变化趋势;(2)随着退化程度增加,退化草地土壤中含水量逐渐降低,全氮、全钾、有机质、速效钾含量未表现出逐渐降低趋势,而草地的裸斑面积、土壤及养分的流失量逐渐增加;(3)人工草地及退化草地土壤中全氮、速效钾、有机质含量均随着取样深度增加而逐渐降低,草地恢复年限和退化程度基本不影响养分在土壤中的空间分布;(4)人工草地建设使退化草地有机质、全氮、全钾的含量增加,尤其有利于0-4cm的土壤养分增加。因而,人工草地建设可以作为三江源区退化草地土壤恢复的措施之一。     

不同人工草地对干旱区弃耕地土壤理化性质及微生物数量的影响

在宁夏干旱区弃耕地种植6种牧草建植人工草地,对表层土壤理化性质、土壤养分含量及微生物数量进行研究,探讨不同人工草地对弃耕地土壤理化性质及微生物数量的影响。结果表明:各人工草地的土壤容重、pH、全盐均低于撂荒地,其中全盐含量显著降低;各禾本科草地保水蓄水能力均强于豆科草地,以披碱草的效果最佳;各人工草地的土壤有机质、全氮、速效氮和速效磷含量均显著高于撂荒地,且豆科草地提高土壤有机质、全氮、全磷、速效氮含量的效果强于禾本科草地,效果大小为紫花苜蓿沙打旺草木樨;禾本科草地提高速效磷、速效钾含量的效果强于豆科草地,效果大小为披碱草扁穗冰草蒙古冰草;各人工草地表层土壤细菌、真菌和放线菌数量均显著高于撂荒地;各豆科草地细菌数量均显著高于各禾本科草地,而真菌数量较禾本科草地少,紫花苜蓿和沙打旺草地细菌、放线菌数量均显著高于其他人工草地;禾本科中披碱草草地细菌数量显著多于扁穗冰草和蒙古冰草;土壤水分与放线菌、真菌数量呈显著或极显著正相关;土壤全盐与放线菌、真菌数量呈极显著负相关;土壤有机质、全氮、全磷、速效氮、速效磷含量与细菌、放线菌数量呈显著或极显著正相关,土壤全钾、速效磷、速效钾含量与真菌呈极显著正相关。     

平朔矿区露天煤矿排土场复垦类型及微地形对土壤养分的影响

研究土地复垦类型及微地形对土壤养分的影响对于指导土地复垦实践,控制复垦土地水土流失等具有重要的理论意义和实际应用价值。以平朔露天煤矿排土场为例,借助数理统计方法分析评价复垦类型与微地形因子(高程、坡度、坡向)对土壤有机碳、全氮、全磷、有效磷及速效钾含量的影响。结果表明:(1)复垦类型对各项土壤养分含量影响较为显著,不同的复垦类型中,各项土壤养分含量排序均为耕地林地草地;其中,土壤有机碳、全氮、全磷及速效钾含量,耕地分别为草地的2.15~2.68倍,林地的1.48~1.78倍,对于土壤有效磷,耕地中的含量为71.24mg/kg,为草地的11倍,林地的4倍;(2)坡度与土壤养分含量之间存在显著的相关性(p0.05),而高程、坡向与土壤养分含量的相关性较弱,表明排土场复垦区土壤养分受坡度影响较大,而受高程与坡向的影响较小;(3)复垦类型与坡度的交互作用对土壤养分含量产生一定的影响:同一复垦类型的不同坡度的土地养分含量存在差异,耕地的土壤养分含量随着坡度的增大在降低;同一坡度,不同的复垦类型条件下,土壤养分差异显著,总体趋势为耕地林地草地。     

宁南山区不同生态恢复措施对土壤环境效应影响的研究

通过对宁南山区采取不同恢复措施的土壤水分、理化性质及酶活性的研究结果表明：土壤平均含水量最高的是农田18．61％，其次为林地16．73％、人工草地9．95％，最小的为天然草地9．20％；土壤总孔隙度、土壤碱解氮排列顺序为林地〉农田〉人工草地〉天然草地；土壤毛管孔隙度、土壤速效磷平均含量排列顺序为人工草地〉林地〉农田〉天然草地；土壤有机质平均含量为灌木林地〉农田〉天然草地〉人工草地；土壤速效钾的平均含量为天然草地〉农田〉人工草地〉灌木林地。土壤尿酶含量为人工草地〉天然草地=农田〉林地；土壤蔗糖酶、多酚氧化酶的含量为人工草地〉天然草地〉林地；过氧化氢氧化酶的含量为人工草地〉天然草地=农田〉林地。     

川中丘陵区不同利用方式的土壤养分特征研究

通过实地调查、土壤采样分析和数理统计结合的方法，对川中丘陵区5种土地利用方式（水田、旱地、菜地、林地和荒草地）的土壤养分状况进行对比分析，结果表明．土地利用方式对土壤有机质、全氮、全钾、全磷、碱解氮、速效钾和速效磷含量的影响达极显著（或显著）水平；在5种土地利用方式中．土壤有机质和全氮含量由高到低的顺序为：水田〉林地〉菜地〉旱地〉荒草地；土壤全钾和速效钾含量由高到低的顺序为：水田〉菜地〉旱地〉林地〉荒草地；土壤全磷含量由高到低的顺序为：菜地〉旱地〉林地〉水田〉荒草地。     

Release of interlayer potassium in Norwegian grassland soils

Potassium (K) release from sources that are not initially exchangeable is attributed to depletion of interlayer K of micas and clay minerals or weathering of feldspars. The aim of the present study was to estimate the K release from interlayer K. Soil samples from 17 field experiments in ley on a range of mineral soils in Norway were used in the study. The change in K‐fixation capacity was used as an estimate of depletion of interlayer K. It was assumed that the increase in K‐fixation capacity during 3 yr of cropping was equivalent to the amount of K depleted from the interlayer positions. Mean K fixation increased in the majority of the soils during 3 yr of grass cropping both with and without K application. The increase in K fixation indicated that without K application, the K uptake from interlayer K amounted to 43%, 28%, and 26% of the K yield for clay soils, high‐K sandy soils, and low‐K sandy soils, respectively. Including K uptake from exchangeable K in the topsoil and from subsoil, the explained K uptake amounted to 79%, 69%, and 81% for the three groups of soil, respectively. Simple linear‐regression analyses showed that the change in K fixation during 3 yr of grass cropping was best explained by the percentage of clay in the soil.     

施钾对茶园土壤钾素及平衡的影响

盆栽选取四川、重庆典型的砂岩黄壤、灰岩黄壤、酸性紫色土为供试土壤,田间选取在砂岩黄壤上生长了25年的茶园,连续5年研究了施用钾肥(硫酸钾)对茶园土壤钾库及钾素平衡的影响。结果表明:施用钾肥能显著提高土壤钾库的各类钾素,但其绝对含量都呈逐年下降的趋势。土壤中各类钾素的变化因土壤类型而异,土壤各类钾素的增量均为灰岩黄壤砂岩黄壤酸性紫色土。不施钾肥(CK)的盆栽茶树、田间茶树分别每年从土壤取走钾素0.10.g/kg。盆栽三种土壤的钾素年平均流失量分则别为0.18.g/kg(灰岩黄壤)、0.09.g/kg(砂岩黄壤)、0.07g/kg(酸性紫色土),可见种植茶树施用K肥很有必要。     

外源钾对三种不同土壤钾转化影响的研究

采用盆栽试验,在黄棕壤,砖红壤,黑土三种土壤上种植烟草,研究了外源钾对土壤中钾转化的影响,结果表明:在黄棕壤,黑土上,0.0-0.8 g kg-1施肥范围内,随着施钾量的增加,土壤中速效钾和缓效钾的总增量、作物的含钾量均在增加,尤其是在0.8 g kg-1施肥水平时,二者超出了施肥的增加量,说明施钾促进了其它钾的释放;三种土壤中粘土矿物含量为:黑土>黄棕壤>砖红壤。     

钾细菌制剂对土壤钾素的影响探讨

试验K细菌制剂在控制条件和大田下对土壤难溶性K的转化作用,特别是土壤速效钾和缓效钾的动态变化表明,缺K土壤适当施用K细菌制剂,可增加土壤速效钾含量,成熟植株体内K增加32.3％,拔节孕穗期土壤速效钾含量比对照高128.6％,而土壤、磷矿粉、沙子等3种基质平均速效钾含量比对照高160.6％。K细菌制剂不板结土壤和不污染水源。     

Short‐term potassium release and fixation in some calcareous soils

Potassium (K⁺) directly released from primary K‐bearing minerals can contribute to plant nutrition. The objective of this research was to assess short‐term K⁺ release and fixation on a range of intensively cropped calcareous soils. Potassium sorption and desorption properties and the contributions of exchangeable‐K⁺ (EK) and nonexchangeable‐K⁺ (NEK) pools to K⁺ dynamics of the soil‐solution system was measured using a modified quantity‐to‐intensity (Q : I) experiment. Release and fixation of K⁺ were varied among soils. The relation between the change in the amount of NEK during the experiment and the initial constrain was linear, and soil ability for K⁺ release and fixation (β) for all soils varied from 0.041 to 0.183, indicating that 4% to 18% of added K⁺ converted to NEK when fixation occurred. The equilibrium potential buffering capacity (PBC) for K⁺ derived from Q : I experiments had significant correlation (r = 0.75, p < 0.01) with β, indicating that PBC depends not only on exchange properties but also on release and fixation properties. The depleted soils showed higher β value than the other soils, indicating much of the added K⁺ was converted to NEK in case of positive constraint. The range of the amount of EK which was not in exchange equilibrium with Ca (E_min) in the experimental conditions was large and varied from 0.68 to 9.00 mmol kg^–1. On average, E_min amounted to 64% of EK. This fraction of EK may not be available to the plant. The parameters obtained from these short‐term K⁺ release and fixation experiments can be used in plant nutrition.     

Response of soil exchangeable and crop potassium concentrations to variable fertilizer and cropping regimes in long-term field experiments on different soil types

Annual potassium (K) balances have been calculated over a 40‐year period for five field experiments located on varying parent materials (from loamy sand to clay) in south and central Sweden. Each experiment consisted of a number of K fertilizer regimes and was divided into two crop rotations, mixed arable/livestock (I) and arable only (II). Annual calculations were based on data for K inputs through manure and fertilizer, and outputs in crop removal. Plots receiving no K fertilizer showed negative K balances which ranged from 30 to 65 kg ha^?1 year^?1 in rotation I, compared with 10–26 kg ha^?1 year^?1 for rotation II. On sandy loam and clay soils, the K yield of nil K plots (rotation I) increased significantly with time during the experimental period indicating increasing release of K from soil minerals, uptake from deeper soil horizons and/or depletion of exchangeable soil K (K_ex). Significant depletion of K_ex in the topsoil was only found in the loamy sand indicating a K supply from internal sources in the sandy loam and clay soils. On silty clay and clay soils, a grass/clover ley K concentration of ～2% (dry weight) was maintained during the 40‐year study period on the nil K plots, but on the sandy loam, loam and loamy sand, herbage concentrations were generally less than 2% K.     

Studies on controlled potassium fertilizers

Three K silicates having SiO₂/K₂O ratios of 4, 5, and 6 were compared with single and split applications of KCI, (KPO₃)n, and sulfur-coated KCI (SCK-34) for their availability to four cuttings of common bermudagrass. At the rate of 200 mg of K/pot, all silicates applied in fine particles gave the same pattern of yield and K uptake as readily soluble KCl; however, less response to these finely sized K silicates at applications from 200 to 500 mg of K/pot suggests that they supply K more slowly than do soluble sources. K₂O.6SiO₂, when granulated in the size of 0.41-1.2 or 1.65-2.36 rom gave typical yieiJ and K uptake patterns of slowrelease sources similar to those for SCK-34 at both rates of application. (KPO₃) ⁿ supplied K in the same pattern as KCl and no effect of granulation was observed. A better balanced K supply through the whole period and the production of forage of more stable mineral composition is expected by the use of these slow-release K sources.     

Potassium Dynamics in Western Uruguayan Agricultural Mollisols

Knowledge of soil potassium (K) dynamics and quantification of plant-available K reserves are essential for the correct management of this nutrient. The objectives of this study, conducted in six Uruguayan mollisols, were to (i) determine the contribution of plant-available nonexchangeable K to plant nutrition, (ii) compare the ability of the ammonium acetate (NH₄OAc) method and the sodium tetraphenylboron (NaBPh₄) method to determine plant-available K, and (iii) quantify the effect of K fixation and release processes on the ability of both methods to estimate changes in K availability due to different K balances. In a greenhouse experiment, perennial ryegrass (Lolium perenne, cv. Horizon) was grown over a period of 320 days in six soils fertilized with 0, 100, 200, and 400 mg K kg^–1. We measured plant K uptake and the changes in soil K status related to different K balances using NH₄OAc and NaBPh₄. Use of NaBPh₄ resulted in a more accurate determination of plant-available K (R² = 0.97 vs. 0.78) and soil K balance (R² = 0.73 vs. 0.63), but neither of the methods was suitable for identifying positive K balances. However, when positive balances were established by K addition and incubation without plant growth, both methods related well with K balances. Again, NaBPh₄ was better than NH₄OAc (R² = 0.98 and 0.88, respectively). The more accurate determination of plant K uptake and the strongest relationship with K balance of NaBPh₄ was due to the extraction of exchangeable K plus a proportion of plant-available nonexchangeable K. Soil–plant interactions enhance soil K fixation in forms that are available to plant absorption but are not extractable by the chemical methods considered in this study.     

Exchangeable potassium and potassium balances in organic crop rotations on a coarse sand

Abstract. Crops on sandy soils (<5% clay) are exposed to K deficiency due to the small release and high leaching losses of K. Reliable tools are needed to improve the K management in cropping systems with limited K input, such as organic farming where import of nutrients are restricted according to the EC regulations. We investigated K balances and exchangeable K (K_exch) changes in an organic crop rotation experiment. Potassium leaching decreased from 42 kg ha⁻¹ in 1998/99 to 21 kg ha⁻¹ in 2000/01 as an average of a crop rotation (spring barley, grass-clover, winter wheat and pea/barley) with manure application and without catch crops. In the same period, spring K_exch decreased from 5.0 to 3.0 mg K 100 g soil⁻¹ (0–20 cm). The retention of the straw K left in the field after harvest increased with decreasing levels of K_exch. The cereal crops did not respond to K application but in the pea/barley mixture the pea yield increased by 46%. The concordance between measured K balances and changes in K_exch was weak. Exchangeable K is suitable as a tool for K management on a rotational basis, and a K_exch above 3 mg 100 g soil⁻¹ in the autumn should be avoided to minimize K leaching.     

太湖县耕地钾素亏缺及补钾途径

通过对太湖县耕地主要土壤类型的取样化验 ,分析了全县不同土种供钾状况 ,与第二次土壤普查数据相比较 ,速效钾由 70mg/kg下降到 5 0mg/kg ,缺钾面积增加了 2 0个百分点。钾素亏缺的原因是钾素投入总量不足 ;氮磷钾投入比例不当 ;以及淋失损失等。补钾的途径是充分利用有机钾源 ;充分挖掘土壤潜在钾源 ;科学施用无机钾肥