Technologies to Enhance Soil Fertility through Input / Nutrient Management

The general fertilizer recommendation for Soybean is 20:60:20 kg NPK/ha and that of Wheat is 120:60:40 kg NPK/ha to gain a profitable yield from the Soybean-Wheat cropping system. Realizing the low soil fertility status of the Malwa and Vindhyan plateau regions of Madhya Pradesh where the Soybean-Wheat cropping system is being practiced, the Institute has developed specific IPNS recommendation to make the cropping system more profitable. The recommendation consists of the application of 50% recommended rate of NPKS ( Urea 1.75 kg, DAP 65 kg, MOP 16.5 kg, and Gypsum 55 kg/ha) + 5t FYM/ha + Rhizobium (750 g/ha) to soybean and 75% of recommended rate of NPKS ( Urea 158 kg, DAP 98 kg, MOP 25 kg, and Gypsum 83 kg/ha) + Phosphate Solubilizing Bacteria (PSB) (3.5 kg/ha) to Wheat. The technology is found viable since many of the farmers can produce 5t FYM per annum. But, for some farmers it may not be possible to cover the entire holdings with complete INM every year as the FYM available may not be sufficient. These farmers can go for 100% NPKSZn to soybean and 100% NPKS to wheat to those parts of their fields where FYM is not applied, to get higher productivity in the Soybean-Wheat system (Bulletin No.4, 2003, IISS, Bhopal).

Intercropping systems are sustainable as these lower runoff and soil losses compared to sole crops. Field trials conducted at IISS conveyed that Kharif intercropping of Soybean with Maize (2:1 ratio) without any nitrogen application but with 5 t/ha FYM; followed by Wheat in Rabi is found to be more productive and economical with a benefit-cost ratio of 2.37 compared to the mono-cropped Soybean - Wheat System. However, the application of 100% NPK in maize-wheat system will give the highest profitability. Farmers could consider intercropping where soils are susceptible to erosion.

The field burning of crop residues is undoubtedly a wasteful practice as it results in loss of valuable organic matter, and associated nutrients. An experiment conducted for five years has established that soil incorporation of wheat residue plus N supplementation through FYM at the rate of 28 kg N ha-1 (approx. 4 t FYM ha-1) along with 25 kg P ha-1 for rainfed soybean and 68 kg N + 30 kg P ha-1 for irrigated (1+2 irrigations) wheat was more effective and profitable. Wheat residue incorporation resulted in 20-22% higher yields in soybean and 15-25% higher yields in wheat as compared to residue burning. (IISS Publication: Two Decades of Soil Research,2009)

A systematic procedure to diagnose and correct the micro and secondary nutrient deficiencies of Indian soils has been developed by the Institute through its AICRP on micro and secondary nutrients. A micro and secondary nutrients recommendation chart for the application of various micro and secondary nutrients for different crops and cropping systems has been developed (Research Bulletin No. 1/2012, IISS, Bhopal).

Enriched composting is the process where the ordinary compost is fortified with the necessary plant nutrients so that it becomes more or less complete food for the plant. Different types of enriched composts developed by the institute are:

a. Phospho Compost: The technology has been developed using phosphate solubilizing microorganisms (Aspergillus awamori, Pseudomonas strata and Bacillus megaterium) phosphate rock, pyrite and bio-solids to increase the manurial value compared to ordinary FYM and compost. The average P content of this compost is 2-3.50 % and the cost incurred to obtain one kg P2O5 through phosphocompost is around Rs.9.00 as compared to Rs.16.0-17.0 supplied through single super phosphate or Diammonium phosphate (Technical Bulletin (Hindi), Nov. 2000).

b. Phospho-Sulpho-Nitro Compost: In this composting process urea @ 0.5-1% (w/w), rock phosphate @12.5% (w/w) and pyrite @ 10% (w/w) are added into the composting mixture. The average nutrient value of this compost is 1.5-2.3% N and 3.2-4.2% P. Application of phospho-sulpho-Nitro compost @ 5 t/ha can replace 25% of recommended fertilizer dose in Soybean-Wheat Cropping system (Technical Bulletin No.2/2006, IISS, Bhopal).

c. Spent Wash amended Compost: This compost is prepared by heap method but water requirement for the composting is met by spent wash, the major waste material from the distillery industry. Spent wash is rich in organic matter content and a good source of plant nutrients like N, P, K, S etc. After preparation, the nutrient value of spent wash amended compost is 1.37% N, 1.30% P and 1.82% K. The field demonstrations showed that the yield increase by the application of spent wash amended compost is almost equal to that of two other treatments (FYM, Ordinary Compost) in maize. In chickpea the yield increase was on par with th application of recommended dose of NPKSZn, and that of FYM + 50% of NS top dressing (IISS Research Bulletin.No.2, 2012).

d. Enriched Organo - Mineral Compost: In this method of composting, crop residues are mixed with cow dung, low-grade rock phosphate, waste mica and mineral gypsum and the composting period is nearly four months. The nutrient value of enriched organo-mineral compost is 1% N, 1% P, 2.1% K, 1.7% S and the addition of 1 tonne compost can supply 10 kg N, 10 kg P, 21 kg K, and 17 kg S to the crop. Field demonstrations conducted by the Institute proved that yield performance of organo-mineral compost is promising when used as a part of Integrated Nutrient Management (INM) (ACIAR Project Technical Paper (Folder): Phosphorus, Potassium & Sulphurenriched Organo-Mineral Compost Production Technology, IISS, Bhopal).

e. Microbial enriched Municipal Solid Waste (MSW) Compost: The Institute has developed microbial enriched compost technology to make use of the untapped nutrient value of the municipal solid waste as well as to manage the environmental pollution issues related to that. For making 1000 kg microbial enriched compost, 1600 kg waste material, 320 kg fresh cow dung and 21kg Urea are required. To enhance the decomposition process bioinoculum need to be added twice during the composting period; initially in the first five days and then after 30 days of decomposition. The composting period for this method is around 2.5 months and the nutrient value of microbial enriched MSW compost is 0.73% N, 0.79% K with 11.3% total organic carbon content (Institute Publication (Folder): Microbial Enriched Compost Production from Municipal Solis Waste, IISS, Bhopal).

Biofertilizers are preparations of living organisms that are useful for promoting plant growth through a variety of mechanisms like biological nitrogen fixation, solubilization of insoluble phosphates, oxidation of sulphur, production of growth hormones, and also help plants to fight against diseases. (Research Progress Report: Network Project on Soil Biodiversity-Bio fertilizers (2007-2011) IISS, Bhopal).

a. Mixed Consortium Biofertilizers : Mixed biofertilizers (BIOMIX) containing a consortium of N fixers, P solubilizers and Plant Growth Promoting Rhizhobacteria (PGPR) to promote crop growth of cereals, legumes and oilseeds was developed through the Network Project on Soil Biodiversity and Biofertilizers. Field trials conducted at various centers of the Network Project showed that use of BIOMIX could save 25% of N and P fertilizers. Field trials of BIOMIX in various states showed an yield increase of 13% in rice, 9% in wheat, 10% in millets, 13% in pulses, 14% in oil yielding crops, and 10% in vegetables.

b. Enhancement of Biofertilizer Efficacy: Bioinoculants (Azospirillum, Azotobacter, PSB) mixed with well decomposed FYM/Vermicompost in 1:25 ratio and incubated at 30% moisture for a week improved the microbial population 2-15 fold. Demonstrations revealed an yield increase of 8-12% in above ground vegetables and 25-30% in below ground vegetables with the use of this formulation.

c. Liquid Biofertilizer Formulations: Technology developed by ANGRAU, Amaravathi center of Network Project on Biofertilizers. Liquid biofertilizer formulations found to be ideal to increase the shelf life of different biofertilizers. In an evaluation period of 360 days Liquid Rhizobium medium (LM3) maintained log 8.433 viable cells/ml, Liquid PSB medium (LM3) maintained log 8.208 cells, and Azospirillum liquid medium (LM2) maintained log 8.643 CFU/ml even after 360 days. Liquid inoculants found to be free of contamination during the study period and dose of 4-5 ml of liquid inoculum (population of 3x109 cells/ml) is enough to coat 1 kg seed.

To mange the micro-nutrient requirement of the crop a protocol has been developed for the fortification of urea with a consortium of nano-particles of Zinc, Copper, Iron, and Silicon by using oleoresin. This product contains 0.438g N, and 2.2 mg Zn, 1.10 mg Fe, 0.66 mg Cu and 1.06 mg Si per gram of urea. Application of this fortified urea @ 200 kg/ha will supply 87.68 kg N, 440g Zn, 220g Fe, 132g Cu, and 212g Si to the crops. 

Development of Nano Rock Phosphate is an effort towards the commercial utilization of the low grade rock phosphate available in India as a direct phosphatic fertilizer. Experiments conducted in four soils (Vertisols of Bhopal, Alfisols of BetuI, Inceptisols of Ludhiana, and Aridisols of Jodhpur) revealed that crop utilization of P from nano-rock phosphate is on par with that of normal sized SSP in Vertisol and Inceptisol; and biomass growth of maize could be enhanced with the application of nano-rock phosphate. The institute has tested two types of rock phosphate materials SRP (Sagar Rock Phosphate) and HGRP (High Grade Rock Phosphate, Udaipur) and found that nano-rock phosphate (size:110.1 nm) prepared from SRP had showed an yield advantage of 20% in vertisols, 61% in alfisols, 31% in inceptisols, and 14% in aridisols over the application of normal sized rock phosphate (size:13.4 pm) from SRP. Further, nano-rock phosphate (size:70.89 nm) prepared from HGRP had showed an yield advantage of 31% in vertisols, 88% in alfisols, 27% in inceptisols, and 15% in aridisols over he application of normal sized rock phosphate (size:12.9 pm from HGRP (Adapted from ISS Technical Bulletin, 2010).

Results of the experiments conducted at IISS revealed that Nano ZnO can be used as a direct source of Zn to crops. Application of nano Zn particles at relatively lower level (0.28ppm) enhanced the growth of maize compared to normal ZnSO4 (0.5ppm); further, seed treatment with nano-ZnO @ 50 mg Zn/g seed found to be a successful method to meet the Zn requirement of the crop and there was no toxic effect on the seed germination and further plant growth (IISS TechnicalBulletin, 2010).

Technologies to Enhance and Sustain Soil Health

Conservation tillage means any tillage system that maintains at least 30% of the soil surface covered by residue after planting primarily to reduce water erosion The institute has tested different conservation tillage practices (No Tillage and Reduced Tillage) for soybean-wheat system. In no tillage system during the kharif season soybean crop was sown directly with a no-till seed drill while wheat residues were kept on the surface. Under reduced tillage system soybean was sown using a no-till seed drill in wheat residue retained field after one pass ploughing by duck foot sweep cultivator. An increase in soil water retention and soil properties were observed in both systems compared to that of field with conventional tillage but yield advantage was visible in the soybean crop grown in the reduced tillage system. (IISS Publication: Two Decades of Soil Research,2009)

The BBF system consists of semi-permanent broad beds of approxima/tely 100 cm wide, separated by furrow of about 50 cm wide and 15 cm deep with a rolling slope of 0.4-0.7% for safe drainage of excess water; crops can be grown on the beds in 2-4 rows in this system. The system is a good option for cultivating crops in waterlogged areas; beneficial for high productivity, improved drainage, and also for in-situ moisture conservation. During heavy rainfall the furrows safely carry runoff water away without any excess soil loss and can drain the excess water to the water harvesting pond so that it can be used for irrigating the winter crop. On BBF, sole maize or intercropping of pigeon pea with maize crop (rainy season), chickpea (winter season) can be grown with application of recommended doses of fertilizer and FYM @ 5 t/ha. There was an yield increase of 11-18% in BBF system compared to that of flat bed system in the field demonstration. Among five cropping systems viz., soybean-chickpea, maize-chickpea, soybean/maize- chickpea, soybean/pigeonpea, and maize/pigeonpea, maize-chickpea system benefited most by the BBF technology. (IISS Publication: Two Decades of Soil Research,2009)

Organic farming is becoming famous for its nature friendly technology package comprising crop rotations, green manuring, compost and biological control of pest and diseases. The institute has developed specific package of practices for organic farming for crops like soybean, wheat, isabgol, chickpea, pomegranate, mustard, and pigeonpea (IISS Publications: Folders forSoybean, Isabgol, Pigeonpea, Wheat, Chickpea, Mustard, andPomegranate, 2012; Extension Bulletin 1/2006)

Bioremediation is an emerging technology that use microorganism/living plants to reduce and/or remove pollutants or contaminants from soil, water, sediments, and air. Phytoremediation is a tool of bioremediation where the green plants are used in situ for cleaning the contaminated sites. The institute has screened and identified some floriculture plants like marigold, chrysanthemum, gladiolus, tuberose and bio-agents like Trichoderma viridie for the management of heavy metal contaminated areas. 

Data base, Maps and Software to support the management of soil health.

The soil fertility data on N, P, and K index values at district level for the states of Andhra Pradesh, Maharashtra, Chhattisgarh, West Bengal, Haryana, Orissa, HP, Karnataka, Punjab, Tamil Nadu and Bihar have been developed in MS-Access. From the attribute database, the different thematic layers were reeclassified to generate various thematic maps on N, P and K index values (IVs). The calculated soil test values were incorporated into the developed fertility maps to prescribe nutrients for targeted yields.

This application software was developed to recommend fertilizer doses for the targeted yields of various crops. This system has the facility to input actual soil test values at the farmers' fields to obtain optimum fertilizer doses for nitrogen, phosphorus, and potassium. The application is a user-friendly tool. It will aid the farmer in improving the efficiency (appropriate dose) of fertilizer use to achieve a specific crop yield. The system works as a ready reckonner to give prescription in the form of fertilizers (eg. Urea, SSP, MOP etc.). The software can be accessed at http://www.iiss.nic.in. The software is compatible with Internet Explorer. On entering the site one has to click "Run the software" shown in bold green colour. (please enable pop ups before clicking). After that one has to feed the information as directed (TechnologyBulletin No. IISS/GIS/01, 2007).

The database has been generated in MS access. This database can be accessed by user friendly queries. To access the data one has to open the file Nutrientdatabase.mdb and then click queries. The user will find several queries which when clicked will ask the name of state, district, crop, manure type for which the information is desired. When user feeds the desired name, he will get the nutrient data.

A new soil carbon and nitrogen turnover model has been developed by using the soil and crop dataset of long term fertilizer experiments of India. Soil carbon and nitrogen prediction model is controlled primarily by net primary production (yield), mean annual rainfall and temperature, texture (sand, silt, clay content), bulk density and soil initial carbon content. The model simulates soil carbon dynamics for different annual crops and plant communities. The model works on the principle of soil carbon saturation theory, which suggests soil carbon sequestration rate decreases as the soil carbon content increases and vice-versa. The model computes total organic carbon, Walkley & Black C content, carbon in resistant (passive) and mineralizable (active+slow) pools, carbon stocks, total N, and available N. Soil carbon and nitrogen prediction model uses a yearly time step and the users have to define only initial soil carbon content. The model itself determines the relative allocation of carbon in different pools. The model automatically computes the carbon and nitrogen turnover based upon these parameters and output is displayed in excel sheet.

Municipal Solid Wastes have considerable potential to contaminate the environment but recycling of this waste material through composting can generate valuable resources for augmenting crop productivity. IISS has developed a new method that enable the grading of MSW compost based on its quality and with this grading can be done for Marketable class on a four point scale or for Restricted Use class on a three point scale based on the Fertilizing Index and Clean Index of the MSW compost. The Fertilizing Index is calculated with the weighing factors assigned to the compost quality parameters while Clean Index is calculated based on the weighing factor assigned to different heavy metals as well as their content in the prepared compost. The software developed with this method is available in the institute in a CD format (Institute publication: Grading of Municipal Solis Waste Compost for Safe and Maximum Recycling in Agriculture).