In this Part II, we will show symptoms caused by abiotic factors and give tips through which you can pin-point the cause of the symptoms and take corrective measures.
Identification of Abiotic plant symptoms
Namaskar, Welcome back to soulofkrishi.
We showed in the Part I video general types of plant symptoms due to various factors. In this part II , we will show symptoms caused by abiotic factors and give tips through which you can pin-point the cause of the symptoms and take corrective measures.
Abiotic stresses can be due to deficiencies of any of the 11 essential plant nutrients or toxicities of nutrients, low or high pH, salt injury, water stagnation, aeration problems or chemical injuries like pesticides and herbicides. It may also be due to environmental factors like extreme temperatures like sun burns or frost, drought and floods or due to calamities like hail storms, cyclones, lightning and other such reasons.
Before going into the depth of this we must know where to see such symptoms on the plant for describing it.
Leaves are the primary plant part on which the symptoms first appear. Symptoms of any specific problem are shown on either young or old leaves or in some cases the middle leaves or entire plant leaves. Therefore we must learn to see which is a young leaf and which is an old leaf on a plant. In this chart we have tried to show young leaves and old leaves of different plant types.
Let us see the symptoms which appear only on older leaves as soon as the problem starts on the field.
If the older leaves show yellowing, later turning brown and drying then such symptoms are caused due to nitrogen deficiency in the field.
If the older leaves are turning Dark Green with red or purple colouration and starts drying then it is due to deficiency of phosphorus in the field.
If the older leaves start showing yellowing starting from leaf tip and extending along the margin towards the base of leaves in inverted “V” shape, spreading fast to middle leaves and then the entire plant, then it is most certainly due to magnesium deficiency in the plant.
If the older leaves margins show necrosis with spots on leaves and starts drying and lower leaves wilt or scorch and spreads fast to middle leaves and entire plant then it is certainly due to potassium deficiency in the crop.
Let us move from old leaves to young and new leaves and see if the symptoms are appearing only on these young leaves. Such leaves may be distorted and deformed and become necrotic or they may show different types of chlorosis
If terminal young buds and leaves are dying and become dark brown colour then it is caused due to boron deficiency in the plant
If the terminal leaves and buds do not die but instead become distorted, find difficulty in emerging and later the leaves show cupping then it is caused due to acute calcium deficiency in the field.
If the terminal leaves and buds do not die but instead Plants become stunted, leaves turn bluish green, small, weak and later distorted tips show necrosis then it is caused due to copper deficiency in the crop.
If the younger leaves show different types of chlorosis or yellowing then we have to find out the pattern of such yellowing.
If the entire leaves starting from younger leaves and moving towards middle and older leaves show light pale yellowing then it is certainly due to deficiency of sulphur in the crop.
If chlorosis on younger leaves is only interveinal and the stems become shortened, gives a bushy or rosetted appearance with small leaves then it is due to deficiency of zinc in the plant
If the emerging young leaves are chlorotic with either it being completely white or light yellowish white then it is caused due to iron deficiency in the plants.
Chlorosis on younger leaves, which have reddish brown spots appear and leaves turn light yellowish then it is caused due to manganese deficiency in the plants.
When soil has toxic levels of chemicals then plants show typical symptoms on their above ground parts. Toxicity can also be due to spray of chemicals like herbicides, pesticides and other chemicals.
If the soil is highly saline with soluble salts in soil solution then the plant leaves show strong necrosis on the leaves starting from tip extending inwards and turning to dark brown or grayish then it is caused due to high salinity and excess salt in the soil and water.
If most of the leaves are slowly turning towards yellowish brown with margin necrosis then it may be due to low soil pH.
If the leaves are turning yellowish brown with severe stunted and dead slow growth then it may be due to aluminum toxicity in the root zones. In such case the roots are very poorly developed.
If the soil is saturated with water for a long time like regular drizzling rains and also if the plants are subjected to very cool weather under such situations the leaves start showing chlorosis starting from leaf tops extending slowly towards mid of the leaves and then the whole leaf turns yellow.
If both young and old leaves abruptly show burnt appearance or starts cupping inwards then it may be due to spray of excess herbicides or pesticides.
In exceptional cases if plants are exposed to poisonous gas or spray of poisonous unknown chemicals as in case of heavy pollution or industrial accidents then the whole plant in that area irrespective of the plant species show burnt appearance.
Apart from deficiency and toxicity symptoms plants also express symptoms due to environmental effects such as extreme temperatures, cyclones, hail storms, lightning, mechanical injuries and so on and so forth.
If the plants are exposed to freezing temperatures then the crop in the fields show sudden symptoms of turning white overnight and wither off uniformly in the field.
If crop is exposed to high temperatures and piercing sunrays then plants show burning symptoms on fruits and young leaves. Particularly on fruits we can notice whitish or yellowish discoloration and shriveling of fruits.
If lightning hits the crops then mostly the tallest tree in the area is affected where the tree crown looses its fronds, stems and overall crown damage
If the field is swept by strong winds as is the case during hurricane and cyclones then the trees or the field crops show severe and irregular lodging and breaking of branches and even uprooting of trees.
If the field is hit by hail storms then the crop is affected both by physical damage and also due to cold temperature. The extent of the damage depends upon the intensity of hail storm. Sometimes the entire fields in the area are lost , orchards are ruined overnight.
Many a times trees may get injury due to mishandling of farm machineries and the trees may get physical injuries as shown in the photo.
With these tips farmers will be able to pin pointedly diagnose and identify the root cause of the symptoms and take up timely corrective measures to save the crop and enhance the yield of the crops.
Should you require further clarification please contact soulofkrishi.com
Please share and subscribe our videos
Thank you Namaskar
Comments