红壤地区土壤镁素状况及镁肥施用技术的研究

从南方各地采集7种不同类型土壤126个样品,测定土壤有效镁含量.结果表明,平均有效镁含量37.2mg/kg.几种土壤类型供镁能力排序为:水稻土＞棕色石灰土＞暗泥质砖红壤＞泥质红壤＞麻硅质红壤＞硅质红壤＞红土质红壤.同样母质发育红壤,其有效镁的含量与植被种类覆盖、土壤侵蚀程度有关,说明植被生态环境对土壤质量产生重要作用.盆栽试验表明,不同镁肥用量对玉米生物量均有不同程度增加,施镁的增产幅度受土壤施钾水平的制约,大量施用钾肥,更引起土壤供镁量不足,钾与镁有相互制约的作用.大田施用镁肥,以红壤旱地上黄豆、花生增产幅度最大达25%～40%,其次是茶叶、烤烟,增产幅度20%～25%,水稻增产幅度较少仅有6%左右.施镁肥增产幅度与土壤有效镁含量和作物品种有关.镁肥品种以含镁石灰性物质或水溶性镁化合物较好.     

闽东南旱地土壤镁肥肥效与钾镁平衡施肥技术研究

闽东南旱地土壤的24个代表性土样测定结果表明,缺镁土样占71%;花生增施镁肥增产幅度为3.7%～25.8%,大豆和柑桔则为7.5%～15.7%;在钾肥最佳用量基础上配施镁肥,镁肥的增产作用最大,钾镁平衡施肥才能大幅度提高花生、大豆和柑桔产量.     

下蜀黄土镁素状况及小麦对镁肥的反应

对下蜀层发育土壤进行镁的分析测量表明，该土壤上层水溶性镁含量不足，剖面其余各层或交换性镁饱和度过低，或钙／镁过大，或镁／钾过小造成作物缺镁；部分冲积的肥沃水稻土，尽管钙／镁不高，镁饱和度高达２０％以上，镁／钾亦远超过临界值，但盆栽试验及田间小区试验结果显示：施镁增加小麦叶片叶绿素含量，促进植株氮，磷，镁的吸收，改善穗部性状，提高产量，试验结果还表明，在下蜀层发育的土壤施用钙镁磷肥的肥效并不次于过磷     

不同氮源与镁配施对甘蓝产量、品质和养分吸收的影响

采用田间试验和室内分析相结合的方法,研究不同氮源与镁配施对甘蓝(Brassica oleracea L.)产量、品质和养分吸收的影响。试验在等氮条件下设4个氮源,分别为不施氮肥、100%铵态氮、50%铵态氮+50%硝态氮、100%硝态氮;设4个硫酸镁施用量,分别为0、75 kg·hm-2、150 kg·hm-2、300 kg·hm-2。结果表明,100%硝态氮与中量(150 kg·hm-2)镁配施处理的甘蓝产量比不施肥处理、100%铵态氮与中量镁配施处理和50%铵态氮+50%硝态氮与中量镁配施处理分别增产56.9%、14.7%和5.2%。施用100%硝态氮处理的甘蓝产量略高于50%硝态氮+50%铵态氮处理,比施用100%铵态氮处理和不施肥处理分别增产13.0%和44.2%。施用低量(75kg·hm-2)镁肥的甘蓝产量比不施镁肥增产9.3%,而增加镁肥用量对甘蓝产量没有显著影响。施用100%硝态氮、50%铵态氮+50%硝态氮和100%铵态氮处理的甘蓝硝酸盐含量比不施氮肥处理分别增加84.4%、63.4%和6.9%。100%硝态氮与高量(300 kg·hm-2)镁肥配合施用的甘蓝硝酸盐含量比不施肥处理、100%铵态氮与高量镁肥配施处理和50%铵态氮+50%硝态氮与高镁肥配施处理分别增加101.4%、82.3%和14.1%。施用高量镁肥处理甘蓝硝酸盐含量比不施肥处理增加11.2%。随着硝态氮比例增加,甘蓝维生素C、还原糖、总氨基酸含量相应增加,镁肥施用量对甘蓝维生素C、还原糖、总氨基酸含量影响明显。随着硝态氮比例增加,甘蓝对磷、钾和钙吸收量显著增加;随着镁施用量增加,磷、钾和镁吸收量相应增加。不同氮源与镁肥相互作用对甘蓝维生素C含量,氮、磷、钾、钙和镁养分吸收均有明显的影响。本研究表明,50%硝态氮和50%铵态氮混合与适量镁肥配合施用,既能增加甘蓝产量,提高维生素C、还原糖和总氨基酸含量,又能减少硝酸盐含量,提高甘蓝品质。     

闽东南旱地土壤镁肥肥效与钾镁平衡施肥技术研究

闽东南旱地土壤的２４个代表性土样测定结果表明,缺镁土样占７１％;花生增施镁肥增产幅度为３．７－２５．８％,大豆和柑桔则为７．５－１５．７％;在钾肥最佳用量基础上配施镁肥,镁肥的增产作用最大,钾镁平衡施肥才能大幅度提高花生、大豆和柑桔产量。     

胡椒施用白云石灰和微量元素的效果初探

在浅海沉积物砖红壤胡椒园上，白云石灰配施微量元素可显著提高胡椒产量，白云石灰加锌效果最佳，白云石灰加钼效果次之，施硼则没有增产效应。植株钙，镁。锌、硼含量白云石和微肥的施用而提高、氮、磷、钾的含量未受影响。     

红壤地区土壤镁素状况及镁肥施用技术的研究

从南方各地采集７种不同类型土壤１２６个样品,测定土壤有效镁含量。结果表明,平均有效镁含量３７．２ｍｇ／ｋｇ。几种土壤类型供镁能力排序为：水稻土〉棕色石灰土〉蝉泥质砖红壤〉泥质红壤〉麻硅质红壤〉硅质红壤〉红土质红壤。同样母质发育红壤,其有效镁的含量与植被种类覆盖、土壤侵蚀程度有关,说明植被生态环境对土壤质量产生重要作用。盆栽试验表明,不同镁肥用量对玉米生物量均有不同程度增加,施镁的增产幅度受土壤施钾     

三种镁肥在酸性土壤柑橘园中的施用效果

土壤酸化会加剧土壤和柑橘树体缺镁,施用镁肥是解决柑橘园缺镁的主要措施。目前农业生产中常以硫酸镁(MgSO4)等价格较低、溶解性较高的镁肥形态为主。但其水解性较强且为速效性镁肥,养分易淋洗损失,难以满足柑橘等多年生作物的生长所需。因此,在柑橘园中施用何种镁肥的效果更好则需进一步研究。以降低土壤酸度、补充土壤和柑橘树体镁素、提高柑橘产量和品质为主要指标,评价了酸性缺镁土壤上MgSO4、碳酸镁(MgCO3)和氧化镁(MgO)3种常用镁肥的施用效果。连续两年的田间试验表明,不施镁处理的耕层(0～40 cm)土壤交换性镁含量从27.7 mg/kg降低至22.5 mg/kg,与不施镁肥处理相比,施用镁肥则增加至29.2～34.5 mg/kg,且土壤pH与交换性镁含量呈极显著正相关关系;其中,MgCO3对降低土壤酸度和增加土壤交换性镁的效果优于MgSO4和MgO。另外,施用镁肥显著提高了叶片镁含量,降低了钾含量,使叶片钾镁比和钙镁比趋于合理,其中以MgCO3施用效果最佳。此外,酸性缺镁土壤施用3种不同镁肥均能增加柑橘挂果量并提高果实产量,MgSO4、MgCO3和MgO处理分别比不施镁处理增产5.7%、28.4%和12.5%。同时,与不施镁处理相比,施用MgCO3及MgO的果实风味品质得到进一步提升。各施镁处理中果实可溶性固形物和维生素C含量分别平均增加8.41%和1.46%。酸性缺镁土壤柑橘园中,MgCO3在协同调酸、补镁、增产和提质方面的效果较好,MgO次之,MgSO4较低。这些结果为酸性缺镁土壤上有效解决柑橘园的缺镁问题提供了有益的探索和技术支撑。     

镁肥对小白菜产量、矿质元素吸收及土壤肥力的影响

中国南方红壤区菜地普遍存在缺镁现象,蔬菜生产上适量添施镁肥具有重要的现实意义。目前有关蔬菜施用镁肥的效应研究报道尚不多,尤其是我国南方红壤区菜地的相关研究则更少。采用田间小区试验方法,在农户常规施用化肥的基础上,对红壤菜地添施不同剂量的镁肥,研究施镁对蔬菜产量、营养元素吸收及菜地土壤基本肥力状况的影响规律。结果表明:在常规化肥施用的基础上,适量地添施镁肥(施硫酸镁112.5~450.0 kg hm~(-2)),小白菜增产幅度为12.4%~20.4%,氮、磷、钾及镁等营养元素的吸收量分别提高27.7%~42.5%、30.1%~84.9%、38.0%~80.3%和53.2%~131.9%,蔬菜收获后土壤全镁和交换性镁含量分别提高15.8%~68.4%和29.0%~119.0%。小白菜产量与施镁肥量可用一元二次方程y=-0.53x2+60.61x+9093(R2=0.961**)较好地线性拟合,由该方程可以得出,当施硫酸镁量为381.2 kg hm~(-2)时,小白菜可获得最高产量,即10825.8 kg hm~(-2)。     

沙田柚配施钾及不同形态镁、硫肥的效应研究

本文研究了钾肥及不同形态的镁、硫肥配施对沙田柚的营养生长、柚果产量、品质及效益的影响,结果表明:施镁可大大减轻沙田柚叶片的缺镁症状;在土壤含钾、硫较丰富,镁含量中等的情况下,施用镁、硫肥配施仍然有较好的增产、增效作用,在一定程度上改善了柚果品质;配施碳酸镁及硫磺的产量和经济效益优于硫钾镁肥。     

我国东南部地区红壤表土养分的淋溶及再分布

The leaching and redistribution of nutrients in the surface layer of 4 types of red soils in Southeast China were studied with a lysimeter experiment under field conditions. Results showed that the leaching concentrated in the rainy season (from April to June). Generally, the leaching of soil nutrients from the surface layer of red soils was in the order of Ca > Mg > K > NO₃-N. In fertilization treatment, the total amount of soil nutrients leached out of the surface layer in a red soil derived from granite was the highest in all soils. The uptake by grass decreased the leaching of fertilizer ions in surface layer, particularly for NO₃-N. Soil total N and exchangeable K, Ca and Mg in the surface layer decreased with leaching and grass uptake during the 2 years without new fertilization of urea, Ca(H₂PO₄)₂, KCl, CaCO₃ and MgCO₃. Ca moved from the application layer (0~5 cm) of fertilizer and accumulated in the 10~30 cm depth in the soils studied except that derived from Quaternary red clay. The deficiency of soil exchangeable K will become a serious degradation process facing the Southeast China.     

广东省不同母质发育土壤颗粒分布的分形维数特征

采集广东省主要成土母质(玄武岩、砂页岩、第四纪红土和花岗岩)发育的林地、耕地和园地土壤剖面各发生层土壤,测定了土壤颗粒组成、有机质、CEC等理化性质,探讨了不同母质发育土壤颗粒分布的分形维数特征及其与土壤理化性质的关系。结果表明,玄武岩、第四纪红土、花岗岩和砂页岩发育土壤分形维数变幅分别为2.923 9~2.981 2,2.858 8~2.937 7,2.769 3~2.923 1和2.544 6~2.885 6;玄武岩和第四纪红土发育土壤颗粒分布分形维数与砂页岩发育土壤存在显著差异。土壤颗粒分布的分形维数随土壤深度增加呈增大的趋势,相同母质发育土壤的深层土壤颗粒分布的分形维数接近一致。玄武岩和第四纪红土发育土壤颗粒分布的分形维数在不同深度土壤之间变幅较小,砂页岩和花岗岩发育土壤变幅较大。土壤颗粒分布的分形维数与砂粒含量呈极显负相关,与黏粒含量呈极显著正相关,与土壤全磷、速效钾、全铁、CEC、有机质、全氮、碱解氮呈极显著或显著正相关;土壤颗粒分布的分形维数可以作为表征土壤肥力状况指标。     

广东不同母质发育水稻土钾素的固定与释放

本文通过室内模拟和化学方法研究了广东几种不同母质发育的水稻土的钾素的固定与释放特性。结果表明,砂页岩、珠江三角洲沉积物、石灰岩和玄武岩发育的水稻土的固钾量均随钾加入量的增加而增大,但花岗岩发育的水稻土却相反;砂页岩、花岗岩和玄武岩发育的水稻土的固钾量在淹水时最高,而沉积物和石灰岩发育的水稻土则在恒湿时最高;沉积物发育的水稻土的非交换性钾累计释放量和平均释放速率显著高于其它母质发育的水稻土;施钾肥对非交换性钾释放的影响因土壤所含粘土矿物类型而异。     

湖北省4种水稻土养分状况的系统研究

利用土壤养分状况系统研究法对湖北省4个不同地区典型水稻土的养分状况进行了综合评价.土壤化学分析结果表明,鄂东南蕲春县油-稻-稻三熟制区花岗片麻岩母质发育的水稻土(1#土)、鄂中荆门油-稻两熟区Q3母质发育的水稻土(2#土)、鄂北襄樊市麦-稻两熟区Q3母质发育的水稻土(3#土)、江汉平原洪湖市油-稻两熟区近代河流冲积物母质发育的水稻土(4#土),均主要缺乏N、P和K.并且4种土壤N的缺乏程度依次为3#＞4#＞1#＞2#、P为1#＞2#＞3#＞4#、K为1#＞3#＞4#＞2#.以高粱为指示作物的生物试验结果表明,1#土主要缺乏N、P、K,Zn:2#、3#和4#土主要缺乏N、P,同时施K也有一定效果.生物试验结果表明4种土壤N缺乏程度为3#＞2#＞4#＞1#,P为3#＞1#＞2#＞4#.结果显示土壤化学分析和盆栽生物试验判定养分丰缺种类结果基本一致.但两种方法判定的养分缺乏程度顺序不一致.     

ALLEVIATING THE INFERTILITY OF AN ACID SULPHATE SOIL BY USING GROUND BASALT WITH OR WITHOUT LIME AND ORGANIC FERTILIZER UNDER SUBMERGED CONDITIONS

A study was conducted into the alleviation of the infertility of an acid sulphate by using ground basalt with or without ground magnesium limestone (GML) and organic fertilizer. Fresh soils were treated with the amendments and subjected to two cycles of submergence and drying. The soil was dominated by kaolinite, mica and smectite. The untreated soil pH was <3·5 and solution Al was high. GML application at 4 t ha⁻¹ was able to increase pH and subsequently reduced Al toxicity sufficiently to allow for rice growth. After 4 months of submergence, the pH of the sample treated with 4 t ground basalt ha⁻¹ had increased from 3·61 to 3·94, with concomitant decrease of Al. In the same cycle, the soil pH increase was much higher (reaching 5·22). Ground basalt is thus comparable with GML as an acid soil ameliorant. Within the experimental period, the ground basalt had mostly disintegrated and dissolved. The solution pH had further increased (to 5·94) in the second cycle because of dissolution of more ground basalt. This means that it takes time for ground basalt to completely dissolve and consequently supply Ca, Mg, K and P to the growing crop in the field. Applying 0·25 t organic fertilizer ha⁻¹ into the soil had no significant effect on either pH or Al. This form of organic matter (compost) contains essential nutrients. It is recommended that 4 t ground basalt should be applied in combination with 0·25 t organic fertilizer ha⁻¹ a few months ahead of the growing season for maximal benefit. This study showed that ground basalt can be effectively used to ameliorate highly acidic soils. Copyright © 2011 John Wiley & Sons, Ltd.     

MAGNESIUM DEFICIENCY IN CHESTNUT GROVES: THE INFLUENCE OF SOIL MANGANESE

In northeastern Portugal, it has been difficult to identify the threshold value of exchangeable magnesium (Mg) below which Mg deficiency occurs in chestnuts (Castanea sativa Mill.), since discrepancies have been observed in some areas, apparently associated with parent material. A regional survey was carried out in chestnut groves established in soils derived from bedrock of several geological formations, some of them rich in manganese (Mn). Leaf sampling and soil analysis were performed in 38 groves. The lowest value of foliar Mg concentration under good growing conditions was 1.8 g kg^?1 and the highest value in trees with Mg deficiency symptoms was 1.5 g kg^?1. Under acidic soil conditions higher levels of extractable Mn propitiate Mg deficiency. The soils need to reach higher exchangeable Mg (≥0.34 cmolc kg^?1) in order to supply Mg. For lower values of extractable Mn, the deficiency appears when exchangeable Mg is <0.20 cmolc kg^?1 of soil.     

INFLUENCES OF PHOSPHORUS DEFICIENCY ON THE UPTAKE OF NITROGEN,POTASSIUM, CALCIUM,MAGNESIUM, SULFUR,AND ZINC IN LOWLAND RICE VARIETIES

A field experiment was conducted to study the effect of phosphorus (P) deficiency on the mineral nutrition of five modern, high-yielding rice varieties, Purbachi, BR1, BR3, BR14, and BRRIDHAN29. The available P in the soils of different plots of the experimental field varied from 2.8 to 16.4 mg kg^?1. Such a wide range of available P in the different plots resulted from differences in the amounts of P (0 to 480 kg ha^?1) applied over a period of 8 years during a previous long-term P fertilizer trial in the same field.

The relationship among the P, potassium (K), and magnesium (Mg) concentrations in rice straw and grain in a soil P deficiency situation were especially noteworthy. The K concentration in rice straw was negatively correlated with the P concentration (r = ?0.42 to ?0.60), but in the case of grain the coefficient of correlation between P and K concentration were positive (r = 0.60 to 0.74). There was a strong positive relationship between the P and Mg concentration in grain (r = 0.70 to 0.97). These results suggest that the P deficiency in soil does not only affect the P nutrition of rice, but may also affect the uptake of other nutrients, especially that of K and Mg. The concentration of P in rice straw or grain increased or decreased, obviously, with an increase or decrease in the available P level in soil. Of interest, however, was the observed effect of the P concentration on the concentrations of nitrogen (N), K, and Mg in rice straw and grain.     

Influence of dolomitic limestone and N:P:K: Fertilization on the mineral composition of coastal bermudagrass grown under very acid soil conditions

Abstract

The influence of limestone and N:P:K fertilizer rates on elemental composition of Coastal bermudagrass forage was determined to evaluate causes for high yield responses to dolomitic limestone at high N:P:K rates, as well as severe stand loss, and chlorosis of bermudagrass in the unlimed treatments. Increasing N:P:K fertilization resulted in severe Mg deficiency. Maximum yields (when limed with dolomitic limestone) were associated with Mg concentrations of 1.0 g/kg plant tops. Magnesium lost to plant removal, Mg loss to enhanced leaching under N fertilization, and K interference associated with excess K accumulation at high rates of NK inputs all contributed to Mg deficiency. However, the accumulation of excess K, which interfered with Mg uptake when high rates of N and K were applied, was considered to be the primary cause of the observed Mg deficiency.     

Assessing the effectiveness of manure export plus intensive silage cropping for lowering the Olsen‐P status of P‐enriched grassland

A substantial proportion of farmed grassland soils in Northern Ireland (NI) are overly enriched with P and pose a risk to water quality. To address this problem, manure could be exported rather than recycled to P‐enriched land and the latter intensively cropped with grass silage to deplete soil P. To assess the efficacy of such a strategy, a P‐ and K‐enriched grassland site was intensively cropped over a 6‐yr period with fertilizer N alone supplied to support silage growth. By year 6, soil P had declined from index 5 to index 3, and it was estimated that two more years of this management may bring it into the target index 2 range. Soil K, however, declined rapidly from index 4 to index 1 in just 4 yr, with the result that grass production became limited by K deficiency. It was concluded that nonrecycling of manure to P‐enriched grassland under silage management is probably the most effective strategy for lowering soil P status, but care must be taken to prevent K deficiency occurring.     

供镁水平对烤烟生长及养分吸收的影响

采用盆栽土培试验研究了不同供镁水平对烤烟生长和养分吸收的影响。结果表明,施MgSO4量为0.06～1.08 g/kg时,各处理烤烟的生长状况和干物质积累量明显优于对照和施MgSO4 1.88 g/kg。烤烟各器官对钾的吸收最多,氮次之,磷最少,各处理表现一致。施MgSO4量为0.18～0.72 g/kg的3个处理烤烟各器官对氮磷钾的吸收量明显高于其他处理,且在施MgSO4量为0.36 g/kg时达到峰值。当施MgSO4量较低（≤0.06 g/kg）或较高（MgSO4≥1.08 g/kg）时都会抑制烤烟的生长发育、干物质和养分的积累。而烤烟各器官对镁的吸收量则均表现出随施镁量增加而增加的趋势,且各器官镁吸收量表现为:叶＞茎＞根;镁肥的施用能够在一定程度上促进烤烟对镁素的吸收。