Calcium Potassium and Magnesium Cycle

KALIUM (POTASSIUM)Berperan pada metabolismMeningkatkan ketahanan terhadap kerebahanMeningkatkan ketahanan terhadap hama-penyakitMeningkatkan ketahanan terhadap situasi embunBerperan dalam mengatur penyerapan airBerperan dalam metabolism NMeningkatkan kualitas tanaman

PotassiumUnique because it isnt incorporated into some molecule in the plant. It exists in its ionic, K+ form, in solution in cytoplasmTissue levels of 1.5 - 4.0%Functions as a catalyst for biochemical reactionsFunctions in maintaining turgorFunctions in carbohydrate synthesisDeficiencies hard to diagnose

PotassiumFunctionsUsed to form carbohydrates & proteins.Formation and transfer of starches, sugars, & oils.Increases disease resistance, vigor, & hardiness.

PotassiumDeficiency SymptomsMottled, spotted, streaked or curled leaves.Scorches, burned, dead leaf tips & margins.

Adequate PotassiumIncreases root growthIncreases disease and environmental stress tolerance (?)Increases wear toleranceIt sounds like a magic elixir! But the beneficial effects are realized only when compared to K deficient conditions. There is little benefit from adding K to an already sufficient soil!

Diserap tanaman dalam bentuk Ca+2Berasal dari mineral seperti kalsit CaCO3Berfungsi untuk mengeraskan batang serta merangsang pembentukan biji-bijianKekurangan kalsium menyebabkan proses pembelahan sel terhambat, daun keriput dan tanaman lemah

Calcium enters from biosphere in dust or from organismsLike phosphorous, there is no gaseous state so it does not stay in the atmosphereWhen animals die, the calcium in their bodies are decomposed and go into soil

Water can carry calcium to or from soil through weatheringWhen in the soil, calcium is in an insoluble form until it is broken down by microbes into a usable formMineralization can store calcium in rocksCalcium can be returned from root leakageCalcium can be absorbed by plant roots

When absorbed by plants, calcium is now in an organic stateThe calcium can continually be recycled between the plant roots and soilOR herbivores can eat the plants or drink the water and the calcium returns to the biosphereIf the plant or animal dies, decomposers break down the organism and calcium is returned to water or soil

Calcium is a mineral necessary for lifeIn early life, calcium helps build strong bones and teethHelps with muscle contraction and other body processesPlants need calcium to help in cell wall development and their metabolism; stronger cell walls protect from pathogens

Form taken up by plantsCa+2 Mobility in SoilNo, slight mobility in soil solution Mobility in plantMovement occurs in xylem to the leaves (one way ticket)

Role of nutrient in plant growth: Required for cell wall rigidity, cell division of meristems and root tips, normal mitosis, membrane function, acts as a secondary messenger, aids in storage of phosphates in vacuoles, actively involved in photosynthesis and found in the endoplasmic reticulum Role in microbial growth:Needed for Rhizobium and Azotobacter

Interactions with other nutrients: Since Ca+2 is so directly related to pH in solution, it effects all of the other nutrients. When NO3-N is applied to soil, Ca+2 absorption increases in the plant. Increases in Ca+2 in soil decreases Al+3 in acid soils, as well as decreasing Na+ in sodic soils. Increases in Ca+2 taken up by plants cause deficiencies of Mg+2 and K+. MoO4-2 and H2PO4- availability increases with increases in Ca+2 concentrations.

Concentration in plants:Fresh weight of plants typically contains 0.1-5.0%, can contain up to 10% dry weight in leaves before plant experiences toxicity Deficiency symptoms: First seen in the younger leaves of plants, loss in plant structure, under extreme deficiencies gel-like conditions, root development no longer takes place, stunted plant growth

Content present in soils:Tropical soils: 0.1-0.3%Temperate soils: 0.7-1.5%Calcareous soils: >3.0%Largely dependent on parent material of soil and rainfall

Main CycleMore Info

Effect of pH on availability:Depends on mineral Sources of Calcium: Lime (CaO) (Ca(OH)2), Calcite (CaCO3), Dolomite (CaMg(CO3)2, Gypsum (CaSO4.2H2O), any Phosphorus fertilizer, Anorthite (CaAl2Si2O3), biotite, apatite, augite & hornblende.

Calcium deficiency symptonCalcium deficiency symptoms appear initially as localized tissue necrosis leading to stunted plant growth, necrotic leaf margins on young leaves or curling of the leaves, and eventual death of terminal buds and root tips. Generally, the new growth and rapidly growing tissues of the plant are affected first. The mature leaves are rarely if ever affected because calcium accumulates to high concentrations in older leavesApple'Bitter pit' fruit skins develop pits, brown spots appear on skin and/or in flesh and taste of those areas is bitter. This usually occurs when fruit is in storage, and Bramley apples are particularly susceptible. Related to boron deficiency, "water cored" apples seldom display bitter pit effects.

FertilizerCa(NO3)2CaSO4*2H2OAll P Fertilizers

LimeCaO, Ca(OH)2CaCO3CaMg(CO3)2

OtherShellsSlagMarl

MoisturepH of SoilTemporarily held on exchange sites, but tightly held on charged soilsCalcium MineralsLime, Calcite, Dolomite, Gypsum, Florapatite, Plagioclases, Gabbro, BasaltsLeachingCaCl2, CaSO4Major FormMoisturePlantsAnimalsMiningWeathering(dissolution)Decomposition of Plantand Animal ResiduesMovement of calciumIn the presents of moistureMoistureCa2+ removed As plant matter 4x in leaves vs. grainUptake decreases withPresence of high Al3+Soil MicrobesHigher availability of Ca2+Improves uptake of NH3

MAGNESIUM (Mg)

PENDAHULUANMagnesium merupakan nutrisi utama sekunder bagi tanaman.Magnesium dalam tanah terdiri atas magnesium yang terkandung dalam lempung dan partikel organik dalam tanah, dan magnesium yang larut dalam air.

Magnesium diambil oleh tanaman sebagai ion magnesium (Mg2+). Ini berperan kunci di dalam proses fotosintesis

merupakan bahan yang penting untuk klorofil, pewarna hijau pada daun dan dahan. Juga mrp bagian dari enzim nitrogenase.

Kehadiran kation lain dalam tanah, atau penggunaan pupuk buatan dapat menyebabkan penurunan penyerapan magnesium oleh tanaman, misalnya kalsium (Ca2+), potassium (K+), soda (Na+) dan amonium (NH4+). Oleh sebab itu, diperlukan masukan berupa pupuk Mg untuk mendukung pertumbuhan tanaman.

Animalmanuresand biosolidsMineralfertilizersCrop harvestRunoff anderosionLeachingSoil solution potassium (K+)Plant residuesPlantuptakeMineralpotassiumFixedpotassiumExchangeable potassiumInput to soilComponentLoss from soil

International Plant Nutrition Institute*Phosphorus deficiency in corn is expressed as reddish-purple coloration of leaves, especially in young plants. This coloration results from build-up of sugars that cannot be properly metabolized with inadequate P.**