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作物缺钾的纠正

2011-8-14 21:13| 发布者: admin| 查看: 2028| 评论: 0

摘要:   如果你观察到了象在前几页的图片里那样的缺钾症状,那么你的土壤就已经是非常缺钾了,为了使产量损失减到最低程度,应尽快施用钾肥。为防止土壤以后缺钾,需要有一个改善土壤肥力的计划,这就是要在某些年份施用 ...

  如果你观察到了象在前几页的图片里那样的缺钾症状,那么你的土壤就已经是非常缺钾了,为了使产量损失减到最低程度,应尽快施用钾肥。为防止土壤以后缺钾,需要有一个改善土壤肥力的计划,这就是要在某些年份施用比较多的钾肥。如果钾很缺乏,那么氮肥也就无效了。If deficiency symptoms like those pictured on the preceding pages are observedyour soil is very deficient in potassium. To minimize yield lossespotash fertilizer should be applied as soon as possible. Alsoa long-term plan to improve the K fertility of the soil, using high application rates for some years, should be developed to prevent K deficiencies in the future. If potassium is very deficient, nitrogen fertilizer will not be effective

  即使没有发现明显的缺钾征候,土壤有效钾仍有可能不足以获得经济效益最高的产量。通过实验室和田间试验才能测定出土壤钾素水平是否适宜。Even if no visible signs of potassium deficiency are evident, theleve1 of available K in the soil still might not be enough to produce maximum economic yields. Laboratory or field tests would be needed to determine the adequacy of K.

  6.1钾肥施用-影响钾肥施用的因素Potash fertilizer management- Factors affecting potash fertilization practices

  能引起缺钾的土壤、气候和管理措施等因素(见第2页的第三部分),也将影响到如何施用钾肥,从而达到以最低成本获得最高的产量。除了第三部分已提到的条件外,一个好的施肥方案还应考虑到:The same soilclimate, and management factors which may cause K deficiencies(see Section IIIpage 5)will affect how you manage potash fertilizer to get the highest yie1d at lowest cost. In addition to thc conditions mentioned in Section IIIa well-managed potash fertilizer program should also consider:

  6.1.1土壤因素Soil factors

  粘土矿物的种类和数量,以及有多少钾被固定(即变得对植物无效了)。Kinds and amounts of clay minerals and how much Kif anythey canfix"that ismake K unavailable to the plant.

  土壤保持和贮存钾肥呈植物有效态的能力。Capacity of the soil to retain and store potash fertilizer in plant-available form.

  氧的含量,对在饱和的、排水不良的缺氧土壤中不能很好吸收钾的作物,更要引起特别的注意。Oxygen contentespecially for crops which cannot absorb K well in saturatedpoorly drained soils low in oxygen.

  温度,尤其是当土温低,可能减少土壤有效钾和植物对其吸收的地方。Temperature, especially where low soil temperature may reduce available soil K and its absorption by plants.

  6.1.2植物因素Plant factors

  --根系类型(直根还是须根)和根系密度。Type of root system(tap or fibrous)and density of roots.

  --作物种类或品种。Crop species or cultivar

  --产量水平:高产要比低产从土壤中或从施用的肥料中移走更多的钾。Yield level desired∶a high yield requires more K from the soil reservoir or from applied fertilizer than a low yield.

  管理因素Management factors

  --植株密度和间距。Plant population and spacing

  --耕作措施。Tillage practices

  钾肥种类Types of potash fertilizers

  a.一般性质General properties

  多数钾肥是溶于水的,因此,如果有适当的降雨或灌溉水,钾就能迅速地被植物吸收。钾肥不会象许多氮肥那样挥发而损失到大气中去,但它可以被土壤中某些粘土矿物固定而变得对植物无效。在降雨量高或灌溉过量时,钾素还可能由于地表径流或穿过土层进入地下水而损失。后者称之为淋失,只有在降雨量高的地区中的砂质土上,才会有这个问题。The major potash fertilizers are soluble in waterThereforeif there is adequate rainfall or irrigationK can be absorbed rapidly by plants Potash cannot be volatilized or 1ost to the atmosphere as can nitrogen fertilizers. HoweverK may be fixed and made unavailable to plants by certain clay minerals in the soil. Alsounder high rainfall or excessive irrigationlosses of K in surface runoff or in water passing through the soil into the ground water may occur. The latter, called leaching loss, is a problem only in sandy soils in high rainfall areas.

(表:表1 主要的钾盐肥料 )

物质Material

化学式Formula

K2O%

颜色Colour

氯化钾Potassium chloride

KCl

60-62

粉红色、灰色或白色Pink,gray,or white

硫酸钾Potassium sulphate

K2SO4

50-53

白色White

硝酸钾Potassium nitrate

KNO3

44 -46

白色White

硫酸钾镁Potassium magnesium sulphate

K2SO4MgSO4

22

白色White

  

  c.均匀混合的干燥肥料Mixed homogeneous dry fertilizers

  钾肥在化学上或物理上与氮肥和磷肥混合,形成均一的粒状物质,每粒肥料都有同样的NPK浓度,如 N-P2O5-K2O 15-15-1513-13-21 6-20-20%Potassium salts may be chemically or physically combined with nitrogen and phosphorus fertilizers to form homogeneous materials in granular form. Each granule will have the same percentage of N, P, and K with grades like 15-15-l5,l3-l3-21,or 6-20-20% N-P2O5-K2O

  d.干燥原料的散装混合Bulk blends of dry materials

  散装混合肥料是二种或更多种的肥料物质的物理混合,等级与均一混合肥料相似。Bulk blends are physical mixes of two or more fertilizer materials. Grades are similar to those for homogeneous mixes.

  6.3钾肥施用方法Methods of application of potash fertilizers

  在钾肥施用中,应考虑的基本原则如下:General rules to consider in applying K fertilizers include:

  .钾肥应施在根系能吸收到的地方。除非降雨或灌溉水能把钾带到根层,否则不要把钾肥施在没有根系生长的干燥的土壤表面。Apply potash where roots can absorb it; do not apply it to a dry soil surface where no roots are growing, unless rainfall or irrigation water can be expected to move it into the root zone.

  .避免把钾肥施到叶、种子或根上,因浓度过高会引起肥料盐害(如叶片焦枯)。 Avoid applying potash to leaves, seeds, or roots at concentrations which will cause fertilizer-salt damage (i.e., scorching of leaves).

  a.施用时间和次数Timing and frequency of application

  对于绝大多数作物,钾肥应在整地前或整地期间施用,以便使钾肥能在种植前的短时间内与根层混合。对生长季节短的作物来说,如果土壤保存养分的能力低(如砂质土),可在播种后5-10 周再施一次。生长季节长的作物,像茶树、橡胶、油棕和甘蔗等可能每年需要施二次以上。施肥时间可根据作物生长时期、气候条件和采用的施肥方法而定。 For most crops, potash should be applied before or during soil preparation so it is incorporated into the root zone shortly before planting. When short-duration crops are grown in soils with a low capacity to retain nutrients(e.g., sands), a second potash application at 5 to l0 weeks after planting may be required. Long duration crops like tea, rubber, oil palm, and sugar-cane may require more than two applications per year. Timing would depend on crop growth stage, weather conditions, and methods of application available.

  b.施肥部位Placement of potash fertilizer

    条施Band application:

  肥料可以随种子一起施在垄上和垄中,也可施在种子的旁边和下面,或者在作物出土后几个星期或几个月时条施在两侧。而侧施在表土下面,由于肥料被置于根层,而又不直接和种子接触,因此是最好的方法。The fertilizer may be placed in a band either over the row, in the row with the seed, side-banded to the side and below the seed, or side-banded several weeks or months after emergence of the crop. Side-banding below the soil surface is the best method because it places the fertilizer in the root zone but not in direct contact with the seed.

    撒施Broadcast application:

  撒施就是把干燥的肥料均匀地撒在整个土壤表面。整地前或整地时撒施最有效,因为钾肥能进入根层。Broadcast application involves spreading dry potash fertilizer uniformly over the soil surfaceIt is most effective if done before or during the soil preparation so the potash is incorporated into the root zone

  钾肥用量Amounts of potash fertilizer to apply

  下表(见第82页)指出了几种作物用以纠正缺钾和维持土壤钾素水平的钾肥需要量,同时也提出了每种作物的施肥量,但这些施用量只能作为一般的指导,如果可能,应根据土壤和(或)植株分析,研究结果,上面所提到的土壤、植物、气候和管理措施,以及你自己的经验等来决定实际的用量。The table on page 83 indicates the amounts of potash to apply to correct deficiencies and to maintain soil K levels for several cropsFor each crop rates of application have been suggestedbut they should serve for general guidance onlyIf possibleactual rates should be based on soil And/or plant analysesresearch datathe soilplantclimateand management factors mentioned aboveand your own experience



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