. .



Agricultural productivity

Organics and effective micro-organisms (EM) technology

By S.M. Alam, and M.A. Khan
Nuclear Institute of Agriculture,
 Tando Jam, Pakistan.
July 09 - 15 , 2001

Pakistan, though ranked very low in terms of GNP, is rich in natural resources especially those required for agriculture, e.g. vast areas of good land, fair and controlled water supply, climate conducive to year-round cropping and abundant, untiring manpower. Agriculture is a vast and almost all embracing sector in the economy of Pakistan. Contribution of land and water resources towards agricultural production is so overwhelming and dominating that their proper understanding and utilization is extremely necessary for making worthwhile improvements in this field. The problems related to soil and irrigation can be appreciated fully within the overall context of the land and water resources, their use and interaction. The geographic area of Pakistan is 196.7 million acres (79.61 mha) of this, about 49.0 million areas are under cultivation, whereas the rest is being partly used for grazing and forestry' or is agriculturally unproductive due to limitations imposed by unfavourable soil and climate.

The profitability of agriculture in the country is one of the burning issues of the day. This is mainly due to the problems of low productivity of agricultural crops, which is a result of shortage of freshwater resources, both surface and groundwater, and degradation of soil health due to indiscriminate use of chemical fertilizers and very little incorporation of organic residues and composts in the soil. Aridity coupled with shortage of freshwater resources does not help to maintain soil organic matter contents. Therefore, for maintaining the soil productivity, it is necessary to increase organic matter contents of soils in the country. Decomposition of organic matter is essentially a microbiological process.

Soils of Pakistan are deficient in N due to shortage of organic matter in the soils. Therefore, incorporation of organic matter is necessary for improvement and fertility of soils. Recycling crop residues has the advantage of converting waste materials into a useful product that will potentially, increase crop yield. It is reported that heaping rice straw in mounds in fields is a common practice in the Philippines, Indonesia and India. Factors which favour the use of rice straw as a manure include its availability and amounts (varying from 2 to 10 tons/ha per season), elimination of disposal problem, and it being a good source of organic matter. Five tons of straw contain about 2 tons of carbon. Addition of farm yard manure to soil alongwith straw enhances the rate of decomposition of straw and result in more release of nutrients.

The challenge for the 21st century for the rulers of the countries of the world is to feed the world's increasing population. Although, mineral fertilizers provide a way to achieve this, limited availability of fossil fuel makes the cost of fertilizers high. Therefore, complementary use of available renewable sources of plant nutrients like organics and bio-fertilizers is of great importance. A major factor in sustainable agriculture is to prevent chemical and physical soil degradation. Use of inorganic fertilizers alone in intensive cropping systems creates infertility and unfavourable soil conditions. Soil health is deteriorating year after year, but this can be overcome with the use of matter organic and mineral fertilizers. Application of organic matter is essential to maintain both soil fertility, soil structure, and to stimulate extensively biological activity. Waste recycling is one way of improving soil health and its nutrient balance. These include: Household wastes (Kitchen and home gardens, papers, cotton rags, jute and city solid wastes); Agro-processing industry wastes (Vegetable processing units, fruit processing units (apple, mango, pine apple, citrus) olive and palm crushing units, oil sludge/coates etc); Crop wastes (Crop stubbles, roots residues, kee prunes, weeds, shells, husk, sugarcane trash and wastes from plantation crops such as tea, coffee, chicory, cocoa, spices, condiments, etc); Livestock waste (Cow and buffalo dung, horse dung, poultry dropping litter, and wastes from zoo animals); Market yards (Spoilage in fruit and vegetable market yards); Brewery units (Grape and malt residues, spent wash); Slaughter house/Fish waste (Slaughterhouse and poultry processing units waste, fish and prawn wastes); Hotel/Restaurant waste (Precooking and post cooking waste, papers, flowers, leaves and other wastes); Miscellaneous (Bagasse, press mud, sawdust, tree bark waste, aquatic weeds such as water hyacinth, husk and hull ash).

It is impressive to know how fast organic agriculture is spreading out in different countries of the world. Yet among different Asian countries: Korea, Japan and China are consuming higher fertilizer per hectare of land than other countries. However, such high levels may not be necessary to increase food grain production in all the countries, and organic farming may therefore be feasible wastes, since they contain heavy metals which will lead to hazardous effects on soil health.

Average nutrient content of organic fertilizers (%)

Manures

N

P2O5

K2O

Daincha

3.50

0.60

1.20

Sesbania

2.80

0.10

1.40

Sunhemp

2.30

0.50

1.80

Farm yard manure

0.85

0.25

0.65

Neem cake

5.20

1.10

1.50

Castor cake

4.40

1.10

1.40

Cotton seed cake

4.00

1.90

1.60

Coconut cake

3.00

1.90

1.80

Sesamum cake

6.20

2.00

1.20

Groundnut cake

7.30

1.50

1.30

Composted coir pith

1.06

0.40

1.20

Fish meal

4.00

3.90

1.80

Blood meal

10.10

1.20

1.00

Night soil compost

1.40

2.80

4.00

Poultry manure

2.17

2.00

4.20

Goat manure

2.40

0.90

2.00

Sheep manure

1.93

1.70

2.30

Pig manure

3.70

3.30

0.40

Biogas slurry

1.40

0.90

0.80

Fertilizer consumption per ha of arable land and land under permanent crops in Asia

Countries

1995-96(kg of N + P2Os + K2O/ha)

1996-97

Bangladesh

137.1

142.8

China

365.7

266.4

India

81.8

84.3

Japan

375.7

360.5

South Korea

155.1

85.1

North Korea

480.7

479.4

Nepal

31.6

34.7

Pakistan

116.1

111.5

Philippines

63.3

67.9

Sri Lanka

106.0

108.3

WORLD

89.0

89.0

Ranges for heavy metal concentration in sewage sludge

(mg kg-1 dry weight)

Country

Ni

Cd

Zn

Cu

Pb

UK

20-5300

2-1500

600-20000

200-8000

50-3600

USA

12-2800

2-1100

72-16400

84-10400

800-26000

Sweden

15-2120

2 - 171

700-14700

52-3300

52-2900

Canada

07-1500

2 - 147

400-19000

160-3000

85-4000

Australia

20-320

2 - 185

240-5500

250-2500

55-2000

Incorporation of organic matter whether in the farm of crop residue or farm yard manure has been shown to improve soil structure and water retention capacity. In addition, farm yard, manure which contains ( 0.5 % N, 0.26 % P and 5.5 % K ) acts as a source of slow release N. Higher grain yields of wheat were obtained with the incorporation of rice straw ( 0.6 % N, 0.11 % P and 1.64 % K ) and farm yard manure in the soil. Use of straw as mulch has also been advocated to modify hydrothermal regime, depending upon its conducive and reflective properties. It has also been reported that recycled straw modifies the hydrothermal regime, soil structure and nutrient dynamics and favourably affects crop yields. Soil organic matter refers to the sum total of all organic carbon containing substances in soils. The organic matter content of soils ranges from less than l % in desert soils to close to 100 % in organic soils. A typical agricultural soils may contain 1-5 % organic matter in the top 15 cm of soil surface. Soil organic matter consists of a mixture of plant and animal residues in various stages of decomposition of substances synthesized microbiologically and/or chemically from the breakdown products, and of the bodies of live and dead microorganisms and small animals and their decomposing remains.

Organic matter is a key component of soil which influences plant growth through its effects on the physical, chemical and biological properties of soils. It has a physical function in that it promotes good soil structure, thereby improving tilth, aeration and moisture movement and retention. Its chemical function is manifested by its ability to interact with metals, metal oxides, hydroxides and clay minerals to form metal organic complexes and act as ion exchanger and storehouse of some major nutrients such as N, P and S. Soil organic matter has a biological function in that it provides carbons energy, source to N fixing bacteria, enhances plant growth root initiation, yield nutrient uptake, chlorophyll synthesis, and seed germination. Added crop residues after mineralization by the help of microorganisms, improve the soil humus content, water holding capacity, cation exchange capacity, conservation of moisture, water infiltration rate, aeration and porosity and improve agricultural productivity. Usually the greater the amount of organic matter in the soil the better are the physical properties of the soil.

The integrated land use system has to be designed in a way to reduce dependence on chemical fertilizers and agro-chemicals, materials and to provide resources for bio-fertigation using effective micro-organisms ( EM ) technology. The EM technology provides an effective way of initiating nature farming systems in different ecological zones of the country. This technology is promising in amending saline groundwater, infertile soils and thus makes saline agriculture as a profitable enterprise for growing crops. The use of EM technology on regular basis also helps to have better soil structure and reduced tillage requirement. Besides, farming is one of the requirements for zero till agricultural systems, which has demonstrated potential for increased productivity in economic crops.

Literature reveals that there are many possible ways for the development of agricultural system, which make use of the potential of biological processes in the soil in order to replace the use of chemical fertilizers as much as possible. Apparently, biological techniques that use organic residues and litters beneficial to soil micro-organisms in order to improve soil system and plants health could definitely play a significant role in reverting the traditional trend of using agro-chemicals, which are causing tremendous environmental problems in the country. A very regular addition of organic amendment in the soils may generally improve the soil productivity and sustainability of the general cropping systems. The efficiency of these compounds and organic acids produced on decomposition of organic matter vary and benefit of their use mostly depend upon the source of bio-fertilizers and on their properties. However, the advantage of using organic matter has well been identified due to multitude of benefit occurred to the biological production in the soil. The organic materials also improve the microbial activities of the soil, biological N fixation, organic matter decomposition, mineralization, nitrification and antagonism to soil borne pathogens and fermentation are the common features of microbial activities in soil system.

Microorganisms have a long history of domestication by man, providing chemical transformations in soil system which markedly improve in preservability, digestibility and taste of agricultural raw materials through mineralization and breakdown in the soil body. Microorganisms re top geniuses in handling biochemical problems. In recent past, a new technique generally known as effective micro- organisms (EM) liquid culture formulated for use in soil fertility during 1985. The EM-technology is documented to enhance the effectiveness of organic matter by regulating the breakdown of organic materials and releasing nutrients for plants over a long period of time. The development of farming system through EM-technology is not simple farming in that chemical fertilizers and pesticides, but rather it is an organic farming with added dimension of exploiting the existence of beneficial micro-organisms to enhance soil quality and health phenomenon.

Literature reveals that in an average mineral agricultural soil, the activities and presence in numbers of soil microorganisms are as (dry wt/acre to 6"): bacteria 300-700 lbs, fungi 300 lbs, protozoa 30 lbs, earthworms, insects, nematodes etc, 100-200 lbs. In total about 0.1% soil is living and of this 90 % is micro-organisms. Approximately 3x109 bacteria/g of soil are present in a good soil. The above mentioned microorganisms are generally present in a normal agriculture soil. Thus, we can assume that there may be very much population of these microorganisms in a soil work out with the association of effective microorganisms technique. The presence of these microorganisms will definitely enhance the fertility of a soil and finally the agricultural crop productivity in the country. Such phenomenon will definitely increase the economy of the country. Because it indicates a process of effective microorganism phenomenon.

In areas in which high soil temperature, the rate of decomposition of organic matter and litters by soil microorganisms is very rapid after getting sufficient moisture. It is a very common feature that mineralization in such region is an essential factor for cycling of nutrients in the soil. When green plant material, such as leguminous crop is incorporated into soil, there is a little loss of energy as gas and heat and phytotoxic effect of material occurred with (EM) are degraded through the fermentation process in the soil. The possibility of using this fermentation process in a soil body has been of a great interest to the users and researchers. This can positively reduce the nutrients and energy losses from organic materials caused by naturally occurring oxidative process in the soil and to help decrease microbes in the field. These changes in the soil micro-organisms induced by EM which encouraged the beneficial once and antagonized the pathogens. The application of EM technology as microbial activities phenomenon will definitely improve the soil productivity/quality, enhance crop production and protection, conserve natural resources and ultimately creates a more sustainable agriculture in the long run.