Code No:TMS155Price:Rs2400/-Category:Foods & Agriculture: Inputs to the Soil

Year of Publication : 2001

Table Of Contents : Executive Summary, Importance of Topic, Fertilisers and plant nutritions , Soil Properties, Indian soils, Nitrogen in Plant Nutrition, Phosphatic Fertilisers, Potassic Fertilisers, Secondary Nutrients & Micronutrients, Soil Conditioners, Non-Conventional sources for use as plant nutrients and soil conditioners, Biofertilisers their Potentials, Limitations & Quality control, Emerged salient points, Recommendations & Action Plan, Impact & Spin off if all the recommendations are implemented, Appendix References

The Techno-Market Survey "Non conventional sources of plant nutrients & soil conditioners to Enhance Agricultural Productivity" focuses on the availability, function agronomy of non conventional sources of plant nutrients and soil conditioners in increasing the yield of farm products. The report has covered all the essential plant nutrition components including primary nutrients, secondary nutrients & micro nutrients essential for enhance growth of plant & farm yield and the non conventional sources available in various parts of the country to meet the requirement of these nutrients. Soil is basis of farming business. Good soils are good to the extent man makes use of them. Agriculture modifies soil. Large areas in India are affected by acidity, alkalinity (sodicity), salinity etc. Various properties of soil e.g. physical, chemical & biological properties can be amended suitably by use of soil conditioners.

Due to higher costs of conventional fertilisers & soil conditioner and non availability at the time of requirement of farmer, the locally available non conventional sources of plant nutrients & soil conditioners (industrial wastes, low grade ores, farms/agricultural wastes, sewage sludge, animal & human wastes, green manures, biofertilisers etc.) can play vital role. This will also help to improve the environment & ecology as the wastes can be utilised for enhancing the yield; this will also help to solve the disposal problems of various wastes. Also the environment can be protected from bad effects of production and use of large quantity of conventional fertilisers & soil conditioners for high yield. A reduced import of conventional fertilisers will result in and low pressure on foreign exchange reserves of the country.

Scope and Objective of the study

The scope and objective of the study as given by TIFAC is to address the following aspects in the context of the topic under study.

Importance of Topic

To meet food requirement of growing population on the limited area of land, fertilisers are needed. In addition to food grains, materials for other agro-based industries are also to be produced. Average yield per hectare in India is low. Improved agricultural techniques are required to be adopted to enhance food production, including higher use of fertilisers and soil conditioners. Indian soils are deficient in nitrogen (N) & low to medium in phosphorus (P) & potassium (K). In long term experiments by ICAR, application of NPK fertilisers also resulted in decline in productivity due to deficiency of secondary & micronutrients and organic content. The agricultural production drains out nutrients from soil which are required to be made good to maintain productivity. In 2000 AD, only 20 million tonnes of nutrients are estimated to be added against removal of 29.5 million tonnes by crops. To meet the requirement of conventional fertilisers, India imports large quantity of N & P fertilisers and entire requirement of K-fertilisers. Import of raw material for indigenous production of N & P fertilisers is also necessary. Imports are heavy burden on foreign exchange. Large capital investment to the tune of Rs. 14,000 crores is required during 1999-2000 and 2000-2001 to increase indigenous production. High cost of conventional fertilisers is also a deterrent in increasing use of chemical fertilisers. Non conventional sources of plant nutrients can play a vital role. Use of non conventional sources of plant nutrients, which are locally available & cheap help in bridging the gap of nutrients supply to soil and have low impact on environment & ecology.

There are large areas in the country where soil condition is antagonistic to plant growth. These conditions include acidity (49Mha), alkalinity/sodicity, salinity (7Mha) etc. Soil-conditioners are required to be applied to modify biological, chemical & physical properties of the soil to make it fertile. These include, lime, gypsum, pyrite, industrial & farm wastes etc.

It is evident that to meet the ever increasing requirement of food grain and other farm products from the limited land in the geographical limits of our country, we need more nutrients, and soil conditioners to enhance the productivity. In view of the following facts.

The non conventional fertiliser and soil conditioners which are available in plenty as natural resources and industrial wastes in our country at dispersed locations can be gainfully utilized to enhance the fertility of soil or treat the degraded soils. In addition the technologically improved varieties of the inorganic fertilisers having higher use efficiency can reduce pressure on resources & environment coupled with enhanced agricultural productivity.

Methodology

The Techno-Market Survey was conducted through extensive literature survey on the subject relating to the various possibilities of its utilisation have been explored. Present technological status of exploration & utilisation scenario in India as well as in world has been synthesised and evaluated in the light of ongoing R & D work towards optimum utilisation of the resources in the world. This desk work was followed by -

The draft report would be finalised in accordance with the comments and suggestions, that would be received from TIFAC.

Limitations

During the survey a few difficulties were experienced in collecting informations particularly on detailed aspects of technology and economics. Only a few organisations/individuals were willing to part with the detailed information. However, some insight could be obtained during personal meetings and persuasions. Thus, the report may be read in conjunction with the following limitations :

Market Survey Response

The response to market survey was satisfactory. We got about 20% response from Indian organisations and individuals and about 5% response from foreign agencies (including embassies). It includes the response in reply to our reminders. The information collected during personal meetings and interviews has also been presented. Part list of agencies/organisations/institutions contacted during survey is given in Appendix IV.

The informations regarding technologies and commercial aspects was provided only by a few. Some of the respondents have sent published literature.

Findings of study/survey analysis

Maximum yield results when plants compete successfully for the essentials of life, which include elements for plant nutrition. Sixteen basic elements have been considered essential for plants. Hydrogen, oxygen and carbon are absorbed from air & water where the primary nutrients (nitrogen, phosphorus, potassium), secondary nutrients (magnesium, calcium, sulphur), and micronutrients (chlorine, copper, boron, iron, manganese, zinc & molybdenum) are absorbed from soil, manures & fertilisers.

Plant absorb nutrients in specific ionic forms. Balanced nutrition through fertilisers can maximize farm products. A productive soil should contain all essential plant nutrients in sufficient quantity (but not in toxic qualities) in forms available to plants. If nutrients are deficient in quantity they cause some abnormal conditions & upset the growth of plants. Soil science is synthesis of sciences. Outstanding among the early soil scientists was Justus von Liebig. International Fertiliser Development Center established by UN General Assembly in 1974 provides technical services regarding efficient use of fertilisers. Alternative to conventional fertilisers to meet the nutrient requirements of the plants include biofertilisers, animal manures, sewage sludges, fly ash, green manures, low grade rock phosphate, glauconitic sand, pyrite, slow release nitrogen fertilisers etc.

Soil is basis of farming business and agriculture modifies soil. Top soil is natural body on which plants grow. Proper use of soil can maintain physical, chemical & biological combination of soil, use of soil amendments can improve these properties. Physical properties of soil include its soil texture/structure, soil water and soil air. Chemical properties of soil depend upon composition of its parent material it can be acidic, alkaline or neutral. Soil can contain various salts which come from weathering of parent material or from irrigation water. Organic matter content of the soil is derived from remains of plants and animals.

India has great variety of soils, broadly divided into eight major group of which first four are of agricultural importance; alluvial soils, black cotton/regur soils, red soils, desert soils, forest/hill soils and peaty/marshy soils. The last four type of soils can be put to useful agricultural production by reclaiming these soils using proper soil conditioners and soil amendments.

Nitrogen, an essential plant nutrient, is frequently in short supply in cultivated soils. Its role is connected with vigorous vegetative growth. Soil nitrogen is absorbed
as ammonium & nitrate forms. Nitrogen in organic form is unavailable to plants, it is converted in inorganic forms as bacteria decompose organic compounds. Indian soils are generally deficient in nitrogen. Nitrogen deficiency in plants results in stunted growth & chlorotic appearance. Conventional nitrogen fertilisers are ammoniacal, nitrates, combined ammoniacal nitrates & amide fertilisers Non conventional nitrogenous fertilisers include liquid nitrogen fertilisers anhydrous ammonia, aqua ammonia, nitrogen solutions etc., slow release nitrogen fertilisers (coating of urea with insoluble material or chemically converting the fertiliser into less soluble form or by incorporating urease & nitrification inhibitors). These include sulphur coated urea, polymer coated urea, phosphogypsum coated urea, neam coated urea, lac coated urea, super granulated urea. There are also fertilisers having control release characteristic. Ureaform, isobutylidene diurea, CDU, Oxamide etc. are slow release fertilisers. Work has been done in India in the production of slow release fertilisers, which results in increasing nitrogen efficiency, checking of pollution potential & saving in energy. The modified fertilisers developed at FACT R&D Centre include urea formaldehyde, N:P tablets, gypsum coated urea, sulphur muck coated urea and other controlled release fertilisers. Agronomical results carried out using these fertilisers has given encouraging results. Nitrification inhibitors have been developed in USA & Japan & trials have also been conducted at IARI, New Delhi, India. Pyrite has also property of nitrogen inhibition.

The most important source of N-nutrient is atmospheric nitrogen, which can be fixed by nitrogen fixing bacteria and the process can be symbiotic or non symbiotic. The various biofertilisers include Rhizobium, Actinorrhizae, Azolla, Azotobacter, Azospirillum, Blue-green-algae, etc. Various type of biofertilisers (BF) are being cultured in India. The use of BF is increasing at steady rate and the use of BF is required to be encouraged by giving proper training to the farmers. BF can be used by seeds inoculation or by soil application. Nitrogen recovery can also be increased by use of pressmud cake with nitrogen fertilisers. Organic matter plays important role in efficient use of N-nutrient. Agricultural waste, urban refuse, animal wastes, municipal sewage sludges, green manures etc. are cheap sources of nitrogen-nutrient in addition to other plant nutrients.

Phosphorus, a plant macronutrient is present in soils in varying degree, usually high in virgin soils. Phosphorus concentration in plants is one-tenth of nitrogen. Its storage in seeds prepare them for germination. Soil phosphorus exists in three forms i.e. (i) inorganic compounds, (ii) Organic compounds, and (iii) soil solution. Soil solution is the actual source of phosphorus for plants. Weathering reactions results in releasing of phosphate anions in soil solution from other forms of soluble compounds. Soil solution at any one time is extremely small. Soil pH, temperature, soil organic matter, moisture, surface area of organic minerals etc. are the conditions that influence the release of phosphorus to soil solution. Immobilization of phosphorus reduces its availability to plants. Consumption of conventional phosphatic fertilisers forces India to import the phosphatic fertilisers and raw material for indigenous manufacture of conventional fertilisers. Non-conventional phosphatic fertilisers e.g. low grade rock phosphate can be directly used in acidic soils as cheap alternative. The total recoverable reserves of apatite & phosphorite in India are approx. 170 million tonnes whereas the 124.45 million tonnes of low grade rock phosphate are placed under the category of conditional resources. Direct use of Purulia, Mussoorie & Udaipur rock phosphates have proved good phosphatic fertilisers in acidic soils. Benefaction, calcination, partial acidulation etc. adds to properties of rock phosphate as fertiliser. Other non conventional phosphatic fertilisers include urea nitric phosphate fertilisers, pelphos, bonemeal, steamed bonemeal, basic slag, potassium orthophosphates & potassium polyphosphates, metaphosphates etc. Biofertilisers e.g. Phosphorus solubilizing bacteria, Mycorrhizae (VAM) help in improving phosphorus availability to plants. In addition organic phosphorus sources e.g. crop residue & animal manures are good supplements to meet phosphorus requirement of the plants.

Potassium one of the three macronutrients for plants. The potassium content of fertiliser is given in terms of K2O. It plays important role in plant physiology and improves yield. India imports its entire need of approximately 1.2 million tonnes of potash fertiliser. There is no economically viable source of conventional potash deposit in India. Large proportion of the Indian soils contain potassium, however it, can be classified as `relatively unavailable form', `slowly available form' or `readily available form'. In clay soils there are no leaching losses of potassium whereas, in sandy and organic soils such losses occur. It is important that there should be continuous supply of potash from sowing until harvest. Abundant K supply reduce bacterial population in general in root zone including denitrifying bacteria. K-fertilisers should be applied after soil tests/plant analyses before any symptoms appear on plants. In calcareous soils/recently limed soils having large number of calcium cations, higher level of K is required. Plant roots absorb most of required potassium through soil moisture. Inadequate soil moisture may result poor absorption of K-nutrient by plant. Reduced soil temperature & liming results in low amount of potassium in soil solution. Poor soil aeration also reduces potassium uptake by plants. Conventional K-fertilisers are muriate of potash (KCl) and sulphate of potash (K2SO4). Non-Conventional K-sources include (i) Glauconite a slow release fertiliser. It is available in huge quantity in India. Green sand containing large percentage of Glauconite has been used as potash in USA, England, France, Belgium etc. Glauconitic sand has also been beneficiated to produce commercial fertiliser. R.R.L. Bhopal has attempted extraction of potash from glauconite. Indigenous deposits of glauconite are over 2000 million tonnes spread over in M.P., U.P., Rajasthan & Kerala. Occurrence of these deposits very near to earth surface add to economy. These deposits containing 4 to 7% of K2O, are comparable to New Jersey green sand (average K2O, 6%). Glauconitic sand is suitable for application in acidic soils. 30% of the cultivated land in India is acidic. (ii) The sludge/powder generated during polishing and cutting of granite contains K2O ranging 4-5% in addition to other micro nutrients Mg, Ca, Fe etc. and can be used as K-fertiliser. (iii) Potash salts obtained by beneficiation of marine bitterns. About 7 million tonnes of salt is produced at Indian coast line. As per CSMCRI 2.4 tonnes of potassium Schoenite (K2SO4.MgSO4.6H 2O) can be manufactured for every 100 tonnes of common salt. Other potassium salts obtained from sea bittern include carnallite & Kainite. A lot of work in this direction has been done by CSMCRI, Bhavnagar, Gujarat. (iv) Potash salts produced as by product of aluminum production, cement production, sugar production (molasses) etc. (v) Fly ash from coal-burning power plants.

Secondary nutrients, Ca, Mg & S are indispensable nutrients. High yield varieties remove a considerable amount of these nutrients. Ca is important nutrition in addition to its role as in the correction of soil acidity. Calcium content of soils ranges from 0.5% to 5%. It occurs as insoluble minerals and in soil solution. Ca deficiency is a problem in acidic soils. Role of Ca-nutrients, its deficiency symptoms and calcium fertiliser materials have been discussed. Magnesium is usually abundant in most Indian soils. Its deficiency is observed in acid soils. Exchangeable magnesium is available to plants, Dolomite, Epsom salt, fly ash etc. are sources for magnesium. Sulphur an important nutrient has been reported deficient in many crops in recent years in states like Bihar, Gujarat, Kerala, Punjab, M.P., U.P., Karnataka etc. Soil sulphur is mostly in organic form and available in soil surface. Soil bacteria converts it to the form available to plants. Non conventional sulphur fertiliser materials include gypsum, pyrite, phosphogypsum, potassium/magnesium sulphates obtain from sea bittern, fly ash etc. Elemental sulphur based fertilisers and compound fertilisers are the conventional source of the nutrient. Sulphur is also available from rain water in industrialised areas. Fluid sulphur formulations have proved useful and being used in developed countries. Relative efficiency of sources including non-conventional sources of sulphur has been discussed. Response of sulphur fertilisation in sulphur deficient soils of Madhya Pradesh has been encouraging; a study.

Micronutrients are required in smaller quantities but their role is equally important for plant growth & yield. These include Zn, Fe, Cu, Mn, B, Mo & Cl use of micronutrients in developing countries is an accepted practice. Micronutrient deficiency in Indian soils is on increase Zn deficiency was first noticed in rice in tarai soils & in wheat in soils of Punjab during 1969-70. Deficiency of Fe, Mn & Cu are of lesser intensity. Mn deficiency has been observed in Karnataka soils (19%). Fe deficiency has been observed in Punjab, Haryana, Tamil Nadu, Bihar etc., where as Cu deficiency in Kerala soils (31%). Boron deficiency is prevalent in many parts of the country. In Gujarat & M.P. molybdenum deficiency has been noticed. All the micronutrients, their role as plant nutrient and effects of their deficiency on plant growth & yield have been covered in this chapter including various non-conventional sources for the micronutrients.

To achieve suitable physical chemical & biological properties of soil, soil conditioners are applied. Depending on the pH value & salts contents, the soil can be acidic, saline, saline sodic or sodic/alkaline. The properties of soil can be amended using various methods including leeching the salts with good/rain water, application of chemicals/minerals e.g. gypsum, sulphur, sulphuric acid, pyrites etc. for sodic/alkaline soil, and lime, dolomite, rock phosphate etc. for conditioning acid soils. Industrial wastes are also being used as soil amendments, these include basic slag from steel plants, pressmud and molasses from sugar factories, lime sludge from paper mills, fly ash from coal fired thermal power plants etc. The fly ash is available in plenty in most parts of the country. Fly ash has been found to have properties for amending acidic soil & improving physical properties of soil. Fly ash from some of the coal based thermal power plants has been found to possess quality to amend acidic soils. Various studies have been carried out regarding agricultural utilisation of fly ash. Fly Ash Mission Department of Science & Technology, Govt. of India is the main coordinating agency for utilisation of fly ash.

Non-conventional soil conditioners also include mixture of sewage sludge & fly ash. Organic

amendments are good sources of soil amendment. Lignite can be used as source of humic acid as a soil amendment. Common salt, rock dust, perlite & vermiculite, blue green algae are other non conventional soil conditioner. Vermiculture is also being adopted for improving soil structure & its fertility.

Industrial wastes and low grade minerals can be used as non conventional sources of plant nutrients and soil conditioners. These include fly ash, press mud, molasses, by-product gypsum, sea bittern, basic slag, lime sludge, lignite, dolomite, chalk, low-grade rock phosphate, glauconitic sand, apatite-magnetite, limestone, marble dust, vermiculite, perlite, gypsum, pyrite etc.

Use of biofertilisers & crop response has been discussed in chapter IV & V. Chapter X covers merits of biofertilisers, economics of use of biofertilisers, constraints of use of biofertilisers, method of inoculation, precaution for their use, biofertilisers vs. nitrogen fertilisers, quality control and their standard specification.

Recommendations

Soil should be tested for its properties & to find out deficient nutrients. Non conventional nitrogen fertilisers include slow release urea (coated with sulphur, polymer, neam, lac, gypsum etc.), urea super granules & briquettes, ureaform, IBDU, CDU, oxamide etc. Use of nitrogen inhibitor with urea also reduce volatilisation losses. Biofertilisers are renewable & environment friendly. Non conventional phosphorus fertilisers include low grade rock phosphate (in acidic soils), PAPR, UNP, pelphos basic slag, bone meal, etc. Biofertilisers (VAM) helps is solubilising insoluble forms of phosphorus thus making them available to plants. Animal manures & crop residues are also supplementary sources of phosphorus. Glauconite, granite powder/sludge, potassium schoenite, fly ash etc. are good non conventional potash nutrients. As per "law of minimum" all essential nutrients i.e. primary nutrients (N.P.K.), secondary nutrients (Ca, Mg, S) and micronutrients (Zn, Fe, Cu, Mn, B, Cl) are to be provided for good growth of plant & enhanced farm yield. Fly ash FYM, composts, biogas slurry are good source of many of nutrients. To achieve suitable properties of soil, soil conditioners are to be applied these include gypsum, pyrite, fly ash, rock dust, pressmud, molasses, lime sludge, basic slag, lime, FYM, lignite, organic manures etc.

Educating farmers regarding use of non conventional sources of plant nutrients & soil conditioner is important. Promotional activities are required to be stepped up for utilisation of fly ash as fertiliser & soil conditioner.

The use of non conventional materials as fertilisers & soil conditioners will result in enhanced agricultural production coupled with higher availability of farm product per person in country and reduction of import bill of fertilisers.