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EIS

29
Jan

Fixation of micronutrients in soil

 

  • Boron and molybdenum are generally fixed in rice soil. In case of boron main reaction occur when acid soils are limed.
  • Lime is able to replace Al+3 by Ca+2 and produce insoluble precipitation of aluminium hydroxide/iron hydroxide.
  • This precipitate adsorbs large quantities of boron.
  • Soil high in organic matter also have high Boron.
  • Molybdenum adsorbed strongly by iron/aluminium oxides.
  • Soils high in non crystalline iron on clay surfeces, tend to be low in available molybdenum due to fixation.

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Symptoms and Control Measures for Molybdenum deficiency

 Molybdenum (Mo)

Symptoms

  • Molybdenum is an essential component of the major enzyme nitrate reductase in plants.
  • Its requirement of plants is influenced by the form of inorganic nitrogen supplied to plants, with either nitrite (NO2-) or ammonium (NH4+) effectively lowering its need.
  • It is also reported to have an essential role in iron absorption and translocation in plants.
  • Deficiency symptoms of Mo in rice resembles to nitrogen deficiency (older leaves become chlorotic).
  • Necrotic spots are seen at leaf margins because of NO3 accumulation.

Control Measures:

  • Molybdenum deficiency can be correct by liming of acid soils to pH 6.5 (not preferable if pH change is not desirable for other purposes).
  • Beside these dusting with Na/NH4 @ 100-500 g/ha is very much beneficial.
  • Foliar spay of Na/NH4 molybdate @ 0.1% is also beneficial.
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Symptoms and Control Measures for Copper deficiency

 Copper (Cu)

Symptoms:
  • Copper helps in the utilization of iron during chlorophyll synthesis.
  • Lack of copper causes iron to accumulate in the nodes of plants.
  • It has an unique involvement in enzyme systems of plants like oxidase enzymes, terminal oxidation by cytochrome oxidase, photosynthetic electron transport mediated by plastocyanin etc.
  • It also act as “electron carrier” in enzymes which bring about oxidation-reduction reactions in plants.
  • Sandy, calcareous, lateritic soil, high in organic matter induce Cu deficiency in soil.
  • The main important deficiency symptoms of copper are chlorotic leaves, bluish green leaves, new leaves don’t unroll and leaf tips give needle like appearance, reduced tillering, less pollen viability.
  • Excessive liming in acid soil sometimes cause Cu deficiency in soil.
Control Measures:
  • It can be control by seeding root dipping in 1% CuSO4 suspension, apply Cu @ 5-10 kg/ha once in 5 years in the form of CuO or CuSO4.
  •  Foliar application can be done during tillering to panicle initiation stage.
  • Soil application can also be done with CuSO4 as broadcasting or band placement.

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Symptoms and Control Measures for Silicon deficiency

 Silicon (Si)

Symptoms:

  • Silicon is considered a plant nutrient ‘anomaly’ because it is presumably not essential for plant growth and development.
  • The beneficial effects of silicon have been attributed to correction of soil toxicities arising from high levels of available Mn, Fe2+ and active aluminium.
  • Silicon also provides greater stalk strength and resistance to lodging, increased availability of phosphorus, reduced transpiration etc.
  • Silicon tends to maintain erectness of rice leaves, increases photosynthesis because of better light interception.
  • The oxidizing power of rice roots and accompanying tolerance to high levels of iron and manganese were found to be very dependent on silicon nutrition.
  • The major deficiency symptoms of Si in rice are soft droopy leaves and culms, lodging of plant, severe pest-disease attack.
  • Deficiency generally occurs due to small mineral reserves in organic soil, old paddy soils of subtropical and temperate climates.

Control Measures:

  • Silicon deficiency can be correct by irrigation of water rich in Si, avoid excessive application of N fertilizers, recycling rice hulls or hull ash, apply granular silicate fertilizers like Ca silicate: 120–200 kg/ha; K silicate: 40–60 kg/ha for rapid correction.
  • Foliar spray of Si @0.1-0.2% with sodium silicate improve Si nutrition.
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Symptoms and Control Measures for Manganese (Mn) deficiency

 Manganese (Mn)

Symptoms:

  • The role of manganese is regarded as being closely associated with that of iron.
  • Manganese also supports the movement of iron in the plant.
  • It influences auxin levels in plants and high concentrations of Mn favour the breakdown of Indole Acetic Acid (IAA), takes part in electron transport in photosystem II.
  • Manganese deficiency is very common in upland rice, degraded paddy soil high in Fe content, accumulation of H2S, acid sandy or acid sulphate soil, excessive liming in acid soil etc.
  • Manganese toxicity shows brown spots on the veins of the leaf blade and the leaf sheath in lower leaves. Plant growth are stunted and ultimately cause less number of tillering.

Control Measures:

  • Manganese deficiency can be corrected by application of farmyard manure, acid forming fertilizer (do not use urea), MnSO4 or MnO @ 2-5 kg/ha as multiple application.
  • Chelates should be avoided as Fe and Cu displaces Mn. 
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Symptoms and Control Measures for Boron deficiency

Boron (B)

Symptoms:

  • Boron is concerned with precipitating excess cations, buffer action, regulatory effect on other nutrient elements etc., development of new cells in meristematic tissue, treanslocation of sugars, starches, phosphorus etc., essential for cell wall formation.
  • Boron deficiency occur under moister stress and dry condition which cause reduced plant height.
  • Plants fail to produce panicles if they are affected by B deficiency at the panicle formation stage.
  • The tips of emerging leaves are white  and rolled. Soil application of B (1-2 Kg/ha) is superior to foliar sprays.
  • For hidden deficiency spray 0.2% boric acid or borax at pre flowering or flower head formation stages.
  • Excess of boron appears to inhibit the formation of starch from sugars or results in the formation of B-carbohydrate complexes, resulting in retarded grain formation.
  • The symptoms of boron toxicity are brownish leaf tips and dark brown elliptical spots on leaves, necrotic spot at panicle initiation stage.
  • Use of boron rich ground water, excessive application of boron and high temperature are the main cause of boron toxicity.

Control Measures:

  • Boron toxicity can be controlled by B tolerant variety, use of irrigation water having low boron content, deep ploughing etc.
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Symptoms and Control Measures for Iron deficiency

 Iron (Fe)
Symptoms:

  • The iron content in soil varies from 1% to 20%, averaging 3.2%, but its normal concentration in plants is only 0.005%.
  • Iron deficiency is common in upland, high pH and aerobic soil and toxicity is one of the major constraints to lowland rice production.
  • It disrupts the rice plant physiology in several respects.
  • The critical iron toxicity concentration in plant tissue depends partly on the overall nutritional status of the plant.
  • Iron helps in the formation of chlorophyll.
  • A deficiency of iron causes chlorosis between the veins of leaves and the deficiency symptom show first in the young leaves of plants.
  • It does not appear to be translocated from older tissues to the tip meristem and as a result growth ceases. Iron is also a structural component of nonheame molecules like ferrodoxins (stable Fe-S proteins).
  • Ferrodoxin is the first stable redox compound of the photosynthetic electron transport chain.
  • The main important deficiency symptoms are interveinal yellowing and chlorosis of emerging leaves, less dry matter production, reduced sugar metabolism enzymes, plants become stunted with narrow leaves.
  • Iron deficiency causes chlorosis symptoms in rice plant due to relative immobility of iron in rive plants, interveinal chlorosis on surface of the leaf showing a fine reticulate network of green setting off chlorotic areas.
  • The main reason for iron deficiency are low concentration of iron in upland soil, coarse textured soil, low land soil with very low organic matter content, increased rhizosphere pH etc.
  • Iron toxicity is caused by toxic effects of excessive Fe uptake due to large concentration of Fe in soil solution.
  • The main important toxicity symptoms of iron are tiny brown spots on lower leaves    starting from tip and spread towards the leaf, base or whole leaf coloured orange-      yellow to brown.
  • Spots combine on leaf inter-veins and leaves turn orange-brown and die.
Control Measures:
  • Though it is the most difficult and costly micronutrient deficiency to correct it can be controlled by application of FeSO4 25 kg/ha in between rows, application of
  • iron containing fertilizers or foliar spary of FeSO4 1-3% solution.
  • Leaves appear purple-brown if Fe toxicity is severe Stunted growth, extremely limited tillering.
  • Iron toxicity can be controlled by seed treatment with Ca peroxide @ 50–100% seed wt., intermittent irrigation at tillering stage and by balanced fertilization.

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Symptoms and Control Measures for Zinc deficiency

Zinc (Zn)

Symptoms:

  • It is the most common micronutrient disorders in wet-land rice (often combined with P deficiency).
  • Paddy soil under prolonged submerged condition cause zinc deficiency.
  • Due to increase availability of Ca, Mg, Cu, Fe, Mn and P under prolonged submergence Zn availability and uptake hampered by the crops.
  • Zinc is essential for several biochemical processes such as cytochrome and nucleotide synthesis, enzyme activation, chlorophyll production, maintenance of membrane activity, increase rate of seed and stalk maturation.
  • Zinc deficiencies mainly occur when soil pH is, high organic matter in soil, calcareous soils with high bicarbonate content, intensively cropped soils.
  • Symptoms are common on younger or middle aged leaves.
  • Brown to dusty brown spots on younger leaves (2-4 weeks after transplanting) in red soils, yellowing of leaves/midrib bleaching.
  • Symptoms are prolonged during early growth stages due to immobilization of zinc.
  • Symptoms of zinc deficiency sometimes resembles Fe/Mn deficiencies.
  • Zinc deficiency in rice soil is commonly known as khaira. The main symptom of khaira in rice is usually in nursery; chlorotic/yellow patches at leaf base on both sides of the midrib; restricted root growth and usually main roots turn brown.
  • Zinc deficiency has also been associated with high bicarbonate content, a Mg:Ca ratio in soils>1, the use of high level of fertilizers, intensive cropping, use of high yielding cultivars, and irrigation with alkaline water.  

Control Measures:

  • The most preventing measures for zinc deficiency is selection of Zn efficient variety that is tolerant to high level of bicarbonate as well as low zinc in soil.
  • Beside these application of ZnSo4 in nursery beds, drain the field, seedling root dipping in 2-4% ZnO suspension, mid season correction by spraying 0.5% ZnSO4 thrice at weekly intervals between 3-6 WAT etc.
  • But curative measure for correcting are application of 20-25 kg/ha ZnSo4 in acid soil, 22 kg Zn/ha initially followed by 5-10 kg Zn in the later years or 50% gypsum + 10 t GM + 22 kg Zn once in 2-3 years in sodic soils, 1.0-1.5 kg/ha Zn as foliar spray at tillering stage and 2 times latter is very helpful for correct this deficiency.
  • Plant Zn uptake from low Zn soils can be increased by Zn mobilizing chemical rhizosphere processes. 

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Micronutrient disorders

  • Various agronomic approaches can be used to correct micronutrient disorders.
  • Once a deficiency is reliably identified, it can generally be corrected by chemical amendments that suit the plant demand and farmer options.
  • The amount, form, mode and timing is critical, especially if multiple nutrient stresses and antagonisms among nutrients are present.
  • Toxicities are more difficult to handle than nutrient deficiencies.
  • Direct toxicities occur when excess element is absorbed and retards physiological functions or becomes lethal to the plant.
  • Indirect toxicity may occur through interactions; excess uptake of one nutrient may hamper the uptake, transport and utilization of another nutrient and may result in its deficiency.
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Diagnosis of Micronutrient Deficiency

 

  • Assessment of micronutrient deficiency can be made through visual leaf symptoms and soil and plant analyses.
  • Response of crops to the application of micronutrients not only confirms the deficiencies but also helps in determining nutrient needs.

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Problems in Alleviating Micronutrient Deficiencies

  • Difficulty in the identification of field crop symptoms.
  • Variation in soil micronutrient status, soil pH, and intensity, and seasonal fluctuations in the levels and temperature regimes in the region.
  • Inadequate facilities and field tests to validate soil and plant micronutrients in the region.
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Micronutrient deficiencies in crops

  • Micronutrient deficiencies are widespread. 50% of world cereal soils are deficient in zinc and 30% of cultivated soils globally are deficient in iron.
  • Steady growth of crop yields during recent decades (in particular through the green revolution) compounded the problem by progressively depleting soil micronutrient pools.
  • In general, farmers only apply micronutrients when crops show deficiency symptoms, while micronutrient deficiencies decrease yields before symptoms appear.
  • Some common farming practices (such as liming acid soils) contribute to widespread occurrence of micronutrient deficiencies in crops by decreasing the availability of the micronutrients present in the soil.
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

Sources of micronutrients in soil

  • Inorganic micronutrients occur naturally in soil minerals.
  • The parent material from which the soil developed and soil forming processes determine what the micronutrient content of the soil will be.
  • As minerals break down during soil formation, micronutrients are gradually released in a form that is available to plants.
  • Two sources of readily available micronutrients exist in soil: nutrients that are adsorbed onto soil colloids (very small soil particles) and nutrients that are in the form of salts dissolved in the soil solution.
  • Organic matter is an important secondary source of some micronutrients.
  • Most micronutrients are held tightly in complex organic compounds and may not be readily available to plants.
  • However, they can be an important source of micronutrients when they are slowly released into a plant available form as organic matter decomposes
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

micronutrient management in rice cultivation

 Introduction

  • The term micronutrient refers to the relative quantity of a nutrient that is required for plant growth. It does not mean that they are less important to plants than other nutrients.
  • Plant growth and development may be retarded if any of these elements is lacking in the soil or is not adequately balanced with other nutrients.
  • Micronutrients constituents take part in metabolic activities, enzymatic process/ catalysts etc. Thus these all directly and indirectly help in plant growth and development.
  • There are 8 essential plant nutrient elements defined as micronutrients like boron (B), zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), molybdenum (Mo), chlorine (Cl) and silicon (Si). They constitute in total less than 1% of the dry weight of most plants.
  • Organic sources like FYM, Compost, vermicompost etc. may contain less quantity of these nutrients but presence of these help the plant in their growth and development.
  • They also called trace elements or minor elements. They are required only in small amounts (5 to 200 ppm, or less than 0.02% dry weight).
  • The visual symptoms may be caused by more than one nutrient. Deficiency of one nutrient may be related to an excess quantity of another.
  • Nutrient deficiency symptoms are observed only after the crop has already suffered an irretrievable loss.
  • When soil supplies more quantity of nutrient than the plant’s requirement, plant shows toxicity symptom.

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
29
Jan

New techniques for sustainable production of rice

  • Resource Conserving Technologies

  • Conservation agriculture is a broad term and it includes mainly three conserving techniques that conserve resources
  • Soil cover, particularly through retention of crop residues on the soil surface
  • Sensible, profitable crop rotation; and
  • A minimum level of soil disturbance

A practice that conserves resources and ensures their optimal utilization and enhances resource or input use-efficiency is called resource conserving techniques (RCTs). Mainly these techniques includes zero or minimum tillage (save fuel and time), direct seeding, permanent or semi permanent residue cover, new varieties that use nitrogen more efficiently, laser assisted land levelling, system of rice intensification (SRI), direct seeded rice (DSR), precision farming, use of leaf colour chart (LCC) and integrated crop management (ICM).

File Courtesy: 
Subhash Babu, Raghavendra Singh and S.K. Das, ICAR Research Complex for NEH Region, published in Rice Knowledge Management for Food and Nutritional Security.
29
Jan

Major challenges for sustaining rice productivity

  • Soil degradation
  • Decline water table
  • Inadequate plant population
  • Drop in soil organic matter
  • Nitrate pollution in ground water
  • Emergence of multiple nutrient deficiencies
  • Appearance of new weed biotypes and resistance to applied herbicides
  • Cultivation of rice on light-textured soil
  • Inadequate and imbalanced use of fertilizer
  • Weather aberration
File Courtesy: 
Subhash Babu, Raghavendra Singh and S.K. Das, ICAR Research Complex for NEH Region, published in Rice Knowledge Management for Food and Nutritional Security.
29
Jan

Strategies and modern techniques to enhance rice production in NER

Out of the present deficiency of 1.6 million tones of food grains in the region, 1.0 million tonne deficiency is in rice alone. Main strategy to increase rice production should be through:

  • Developing altitude specific varieties and packages in a participatory mode involving farmers in selection process of such varieties to achieve an average production of 2.2 tfha from the present level of l.8 t/ha from 3.5 million ha of rice area i.e. a gain of 1.4 million tones.
  • Introducing double cropping in at least 25 - 30% of valley land areas of l.5 million ha. i.e. a gain of l.12 million tones.
  • Promoting irrigation facilities by tapping both surface and ground water resources. Present irrigation potential is only 0.88 mhm which needs to be increased to at least 1.6 mhm by tapping the water resources of 42.5 mhm in the region.
  • Breeder seed production for the developed varieties by the concerned institute/ universities, easy access to such seeds need to be ensured. Encouragement and training to youth groups and SHGs for seed production and delivery.
  • In addition to the above, rice varieties for the shifting cultivation areas should be developed to achieve an yield of 1.2 t/ha from the present level of 0.7 t/ha i.e. a gain of 0.8 million tones of rice particularly of glutinous type.
  • Protection and characterization of existing and new germplasm and appending the information to already available database for sharing the information at regional and national level as well as for future use. This is needed to develop a statewise bioresource inventory by the year 2015 and categorise risk level of various germplasm.
  • Molecular characterization of important germplasm for protection of IPR issues and to find out gene flow pattern in highly endangered species of agricultural importance.
  • Establishment of a community rice bio-parks to provide information to general public about conservation needs, judicious and diversified utilization and open up avenues for employment.
  • Demarcation of around 50% jhum areas for organic rice production based on the availability of infrastructure like road, power, storage facilities, marketing, credit facilities and government support.
  • Initially 25% of jhum land per annum may be brought under organic cultivation for three years and remaining 25% in equal proportion in next 2 years. In this way 50% of jhum areas will be covered by 2020. This would result in 15-20% increase in production with 20-30% increase in farm income by 2025.
File Courtesy: 
A.K. Mohanty, Chandan Kapoor, R. Gopi, S. N. Meera and R. K. Avasthe, ICAR Research Complex for NEH Region, published in Rice Knowledge Management for Food and Nutritional Security.
28
Jan

Distribution of problem soils in India cropped to rice

While the diversity in agro ecological environment in the country provide opportunities for growing  numerous commercially viable cropping and farming systems towards a robust agriculture, efficient and sustainable management of natural resources especially soil and water for enhanced soil productivity is vital for over all economy of the country.  Although soil productivity depends largely on a number of its diverse physico - chemical and biological characteristics, the ultimate output is governed by the precise agronomic operations, matching production systems with land capability, efficient management of external inputs like seed, water, nutrient etc., and maintaining a synergy between conservation and exploitation of resources such as soil and water.


Table : Distribution of problem soils in India cropped to rice

Soils

Area(M.ha)

States

Sodic

2.5-3.0

Uttar Pradesh, Punjab, Haryana, Andhra Pradesh, Bihar, Maharashtra, Karnataka, Tamil Nadu

Inland Saline

2.4

Uttar Pradesh, Haryana, Punjab, Rajasthan,

Potential

(15.0)

Maharashtra, Gujarat, Karnataka, Andhra Pradesh,

Coastal saline

2.5-3.0

West Bengal, Orissa, Andhra Pradesh,  Tamil Nadu, Kerala, Karnataka, Maharashtra

Acid soils

49.0
(15.0)

North East Hills, West Bengal, Orissa, North Coastal Andhra Pradesh, Kerala, Karnataka, Goa, Bihar

Acid saline

0.5-1.0

Kerala, West Bengal

Nutrient problems

Deficiency

N,P,Zn,Fe,S,K,Ca,Mn

Toxicity

Fe,H2S,Al, As,Se

 

28
Jan

Soil and management related constraints

Soil and management related constraints in rice production in India can be delineated in following points:

  • Increasing area under soil salinization (8-10 M ha) (salt affected) - major portion is cropped to rice,
  • About 15 M.ha of rice soils are acidic associated with toxicity of Fe, Al, Mn, As, deficiency of K, Ca, Mg, B, Si, and P fixation,
  • About  8.0 M.ha of rice area is deficient in zinc (Zn)
  • Nearly 50 and 80% of Indian soils are responsive (low to medium) to potassium and phosphorous, respectively,
  • Blanket fertilizer management/recommendation over large domains,
  • Nutrient depletion (N, K, S) and loss of soil organic matter in intensive cropping systems,
  • About 3.0 M ha in northwestern states under rice-wheat cropping system affected by Mn deficiency
  • Nutrient problems of deficiency of N, P, K, Zn, Fe, S, Ca, B, and toxicity of Fe, Al, H2 S, As, Se and
  • Overall stagnation or deceleration of growth in productivity of crops and cropping systems    
  • Wet season rice followed by dry season fallow causes considerable buildup of nitrate in soil profiles.
  • This NO3 gets lost from the soil when fields are reflodded  and puddled for planting rice in the following wet season
  • Data indicate that iron (Fe) content of ground water in all the districts is high due to high content of Fe-bearing minerals in soils, and such ground water is not suitable for irrigation unless properly managed Continuous use of such irrigation water causes Fe-toxicity and other nutrient imbalances in crop plants. 
  • It also greatly reduces P-availability in the soil.  
  • Precipitation of iron in surface and subsurface layers may clog the pores of the soils. 
  • As a result, drainage is impeded and crop plants suffer from inadequate O2 supply in the root zone.

File Courtesy: 
Brajendra and Vijai Pal Bhadana Directorate of Rice Research, Hyderabad - Published in Rice Knowledge Management for Food and Nutritional Food Security
28
Jan

Loss of soil organic carbon (SOC)

  •  In India SOC content is most of the soils range from 0.2 to 0.5% (2-5 g/kg soil) which works out to 21 and 156 billion tons up to 30 and 150 cm soil depth, respectively while total soil inorganic C pool (SIC) is about 196 billion tons. 
  • Loss of SOC is alarming due increasing atmospheric temperature and changing rainfall pattern.
  • Extensive mining of soil fertility, removal or burning of crop residues, soil degradation, inappropriate soil tillage and poor crop management, besides accelerated soil erosion (34 – 50 Tg C/yr) are the major reasons for loss of SOC and decline in crop productivity.
  • Technological options for soil C sequestrations in India include INM, green manuring, mulch farming, conservation tillage, residue recycling, and choice of cropping systems, balanced nutrient use with high nutrient use efficiency etc. 
  • Available information on loss of productivity due to soil degradation indicates that it is higher in red soils compared black and alluvial soils.
  • This warrants a knowledge based alleviation of soil problems, and management of soils and inputs keeping in view the resource quality, cropping system, and nutrient flows in the system for the overall sustainability. 
Table :9 Expected loss of productivity due to soil acidity

Soil pH

Degree of acidity

Loss in
Productivity (%)

>6.5

Nil

Nil

5.5-6.5

Slight

Upto 10

4.5-5.5

Moderate

10-25

3.5-4.5

Strong

25-50

<3.5

Extreme

>50
File Courtesy: 
Brajendra and Vijai Pal Bhadana Directorate of Rice Research, Hyderabad - Published in Rice Knowledge Management for Food and Nutritional Food Security
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