 |
| Source: www.nrca.usda.gov |
The year 2015, has been declared as the ‘International Year of Soils’ by
the Food and Agriculture Organisation of the United Nations (FAO). José
Graziano da Silva, FAO Director-General opined, "We must manage soils
sustainably. There are many ways to do this. Crop diversification which is used
by most of the world’s family farmers is one of them: this gives time for
important nutrients to regenerate." IYS is aiming to raise full awareness
among civil society and decision makers about the profound importance of soil
for human life. KDB is also celebrating IYS.
Organic Matter Recycling in Soil for Improving Soil Quality, Input Use
Efficiency and Crop Productivity
The development of agriculture and protection of ecology has been realized
for achieving food security and conservation of soil resource. Since, efficient
utilization of soil resource is crucial to agricultural production for feeding
the ever increasing population of the country. As long as human kind, as part
of this system worked in harmony with nature and used the resources for its
normal sustenance damage to the system was minimal. In traditional agricultural
practices organic sources of plant nutrient had been used to partially
supplement the nutrient requirement of soil.
Written by Ajeet Kumar
Singh and Pankaj Saraswat
INTRODUCTION
Soil is a thin layer of earth’s crust and
is a living media, which is one of the important factors of crop production and
serves as a natural nutrient source for the growth of plants. The components of
the soils are mineral material, organic matter, water and air, the proportions
of which vary and which together form a system for plant growth. The soils are
studied and classified according to their use, which is termed as “land
capability classification”. In this classification, inherent soil characteristics,
external land features and environmental factors are given prominence. For this
purpose soil survey is carried out to record the crop limiting factors such as
soil depth, topography, texture and structure, water holding capacity, drainage
features followed by evaluation of soil fertility based on soil testing / soil
analysis. According to their use the soils are classified into 8 classes, four
of which are considered suitable for agriculture purpose and remaining are
non-arable lands and can be used for silviculture and forest and need strong
conservation measures. An effective linkage between soil testing and soil
survey is useful to ensure formulation of a sound soil fertility evaluation
programme. In the administrative set up, soil survey is generally kept under
the discipline of natural resource management while soil testing remains a part
of the discipline of fertilizer use and management. Proper maintenance of the
soil health, which is necessary from agricultural point of view, refers to the
capacity of the soil to ensure proper physical, chemical and biological
activities/processes for sustaining higher crop productivity. A productive soil
would ensure proper retention and release of water and nutrients, promote and
sustain root growth, maintain soil biotic habitat, respond to management and
resist degradation.
Nutrient Status of Soils Intensive agriculture, while
increasing food production, has caused second generation problems in respect of
nutrient imbalance including greater mining of soil nutrients to the extent of
10 million tons every year depleting soil fertility, emerging deficiencies of
secondary and micronutrients, decline of water table and its quality of water,
decreasing organic carbon content, and overall deterioration in soil health.
Indian soils not only show deficiency of primary nutrients (Nitrogen,
Phosphorous and Potassium) but also of secondary nutrients (Sulphur, Calcium
and Magnesium) and micro nutrients (Boron, Zinc, Copper and Iron etc.) in most
parts of the country. Besides the three primary nutrients (N, P, K), deficiency
of Sulphur and micro nutrients like Zinc and Boron in many of States, and of
Iron, Manganese and Molybdenum in some States, has become a limiting factor in
increasing food productivity. In a comprehensive study carried out by ICAR
through their Coordinated Research Project on Micronutrients, Toxic and Heavy
Metals, based on analysis of 2,51,547 soil samples from different States, it
was found that 48% of these samples were deficient in Zinc, 33% in boron, 13%
in Molybdenum, 12% in Iron, 5% in Manganese and 3% in Copper. Deficiency of
micronutrients needs to be corrected through the application of micronutrient
carrying fertilizers. With regard to response of crops to the application of
micronutrients, under large scale agronomic trials conducted by ICAR, it has
been observed that the additional yield is obtained in cereals in the range of
0.3 to 0.6 ton per hectare. The response of micronutrients in food crops and
vegetables is highly pronounced. Under micronutrient deficient situations, the
application of major nutrients alone does not give expected results. Generally,
NPK consumption ratio of 4:2:1 is considered as desirable based on
recommendation of 120:60:30 NPK kg/ha dose (4:2:1) for wheat/rice. However, the
fertilizer dose has to be worked out based on soil analysis to find out (i)
available nutrient status of the soils and (ii) the crop requirement of the
nutrients; the difference of the two (ii – i) is the required fertilizer dose
for a given crop. Other factors affecting fertilizer use efficiency have to be
built into the computation of fertilizer dose. Studies conducted country wide
under AICRP on Macro and Micro nutrients
reveal that there is a wide NPK use ratio in Northern Zone (13.5:
4.3:1), while it is narrower in Southern Zone (2.9: 1.6: 1). It is 5.6: 3.3: 1
in Western Zone and 5.0: 2.4: 1 in the Eastern Zone. The NPK ratio also shows
wide variations from State to State (FAI 2010). Though, chemical fertilizers
are a major source of nutrients to crops, use of chemical fertilizers alone for
a long period of time leaves unfavorable effects on soil physical, chemical and
biological property and environment. The better approach is to integrate
chemical fertilizers with organic manures to avoid ill effects on soil and
environment. The integration of nutrients results in improved efficiency of
chemical fertilizers and better cost benefit relationship. Organic manures
though low nutrient carrying material, leave a favorable effect on soil
properties. Studies carried out with cereal-based cropping systems under
Cropping Systems Research project of ICAR has established that 25-50%
fertilizer NPK dose to Kharif crops can be curtailed with the use of FYM,
Sesbania green manure and crop residues under different situations.
SOIL QUALITY
Issues
and Strategies: The concept of soil quality is a major linkage between
soil conservation management practices and achievement of major goals of
sustainable crop production (Acton and Gregorich 1995; Parr et al.. 1992). Soil quality indicates “the
capacity of soil to function within natural or managed eco system boundaries to
sustain plant and animal productivity or enhance water and air quality and
promote plant and animal health (Haberern 1992). Thus the management of
land and soil quality becomes of great significance for sustaining crop
production in fragile environment. Land
degradation and deterioration in soil quality are one of the several reasons of
hunger and mall nutrition of human being and are the major threat to food and
environmental security. The predominant reason for poor soil quality (natural
and management linked) are (i) washing away of top soil and organic matter
associated fine fractions due to water erosion resulting in to loss in inherent
soil fertility; (ii) excessive removal of plant nutrients through intensive
cropping without adequate addition of organic manures; (iii) low use of organic
manures such as FYM, Vermi compost and Composts coupled with no recycling back
of farm based crop residues because of complete removal of crop residues from
fields for animal fodder and also burning of stubbles for clean cultivation in
next year. Soil quality parameters (physical, chemical and biological) directly
reflect their bearing on sustainability of crop production by making a bridge
between quantity and intensity (QI) factor of soil fertility. Sustainable
agriculture refers to the ability of agricultural system to remain productive
efficiently and indefinitely.
There are several factors influencing crop production
in hills, better soil quality seems one of them playing important role in
sustaining crop production. At the same time management practices which do not
deteriorate soil quality are also important. Assessment of soil quality for
sustainable crop production is important practice bridging utilization and
protection aspect of soil resource. There exists a strong linkage between soil
quality and crop production. Soil quality characterization and assessment is an
important tool for measuring the changes in soil properties over the time that
helps to define the effective management strategies for sustainable soil
management. Under high input production system soil quality is being given due
recognition for agricultural sustainability and environmental ecology (Smith et al.. 1994). Owing to improper land
use and management, soil erosion, nutrient depletion and other natural resource
related problems have been damaging the soil resource and these calls for
improving soil quality and maintaining sustainability in crop production with
sound land use and management practices (Rozanov 1990). The soil quality, soil health and soil
conditions are synonymous to each as all these terms describe soil’s ability to
support crop growth without becoming degraded or otherwise harming the
environment. The term soil quality has been gaining popularity in present
context of high input agricultural system especially “as farmers are striving
hard to sustain the crop production and maintenance of soil health (More 2010).
In modern agricultural system farmers prefers to percept the term soil health
because it reflect the judgment of their soil as either robust or ailing
resource which is a holistic way to refer soil. However, the soil quality is
defined by the interaction of measurable physical, chemical and microbiological
properties of a particular soil. Therefore, soil quality is distinguished from
inherent characteristics of soil which are not measurable and are acquired and
determined by natural factors such as climate, vegetation, parent material and
time. From productivity point of view all soils have an innate capacity to
function under a definite set of edaphic conditions. In view of ever increasing
population and shrinking of agricultural area due to urbanization and industrialization
in peri- urban areas soil health / quality has to be managed / improved for
increasing cropping intensity. Maintenance and improving the level of soil
organic matter seems a pre requisite for ensuring good soil quality (Singh
2008). In post green revolution era fertilizer consumption rates of the country
has been doubled without adequate attention towards soil health management and
more over nutrition of crops rather than soil
has been given more emphasis resulting into decling fertilizer response
, crop productivity and soil health (Sharma et
al.. 2008). Maintenance of soil quality is of utmost importance to ensure
sustainable agricultural production for providing food and nutritional security
to the peoples of the country. The inadequate and imbalance fertilizer use
coupled with low supply of organic matter to soil has resulted into deterioration
of soil quality.
 |
| Source: www.un.org
|
TRANSFER
OF TECHNOLOGY FOR IMPROVING SOIL QUALITY
Deterioration in physical, chemical and
biological conditions of soil and declining factor productivity causing
stagnation in crop yield are of major concerns of modern agriculture.
Rehabilitation of chemically degraded soils for raising food crops demand
additional technical knowhow and demonstration. Unless the farmers are exposed
to proper training and demonstration for adoption of location specific and need
based technology, the task seems tough. The best prolific knowledge in
agriculture needs to be percolated down to the farmers’ farm through
participatory mode of research. Krishi Vigyan Kendras (KVKs) have been
promoting agriculture through assessment, refinement, and dissemination of
agriculture technologies and products at district level. Effective extension
mechanisms require togetherness of scientists and farmers at district level and
in this connection our KVKs will play a crucial role in the form of knowledge
resource centre. Now a day’s Government has also emphasized Farmers as “FIRST”
in country where FIRST stands for Farmer, Innovations, Resources, Science and
Technology. Therefore, concentrated efforts are to be made for the interest,
aspiration and expectations of farmers. Intensive
cultivation, growing exhaustive crops, use of unbalanced and inadequate
fertilizers accompanied with restricted organic matter recycling (FYM,
biofertilizers and green manures) back in soil have made soils deficient not
only in nutrients but also deteriorated soil quality, resulting in to decline
in crop response to recommended doses of fertilizer. Increasing population load and degrading
environmental conditions have been influencing the long term sustainability of
the soil resource. All agricultural activities are directly or indirectly
affected by how the “soil is handled”, managing soils is a formidable challenge
to ensure productivity, profitability and national food security. The United
Nations Millennium Development Task Force on hunger made “soil health
enhancement” as one of the five recommendations for increasing agricultural
productivity and fight hunger in India as a component of millennium development
goals (MDGs). Major issues of soil health in Indian context include physical
degradation, caused by compaction, chemical degradation due to wide multi
nutrient deficiency, higher nutrient turn over in soil plant system coupled with
low and imbalanced fertilizer use and insufficient input of organic source
resulting into poor nutrient use efficiency, biological degradation due to
organic matter depletion and loss in soil flora and fauna. The inadequate and
imbalanced fertilizer use has created wide spread nutrient deficiency and
deterioration in soil health. Microbial culture with indigenous sources of
organic matter can help in increasing nutrient use efficiency and crop
productivity along with improvement in soil quality. The knowledge of soil
biology can be used for developing bio-remediation techniques through
mobilization of native nutrient reserve to improve soil health and crop
production on sustainable basis. For ensuring long term soil sustainability and
crop productivity return of organic matter to soil along with fertilizer and
soil biotechnology needs to be considered in research and extension programme.
Soil microbial biomass carbon (SMBC) can be considered as an important
biological tool for improving soil health. It is important to realize the
concept of soil health which includes ecological attributes of soil. Soil
biodiversity itself may not be a soil property that is critical for the
production of a given crop, but it is a property that may be vital for
continued capacity of soil to produce crops.
Among all the
concerns related to stagnation in food production, degradation of soil quality
due to excessive use of fertilizers is burgeoning. Integrated Nutrient
Management (INM) refers to the maintenance of soil fertility and of plant
nutrient supply at an optimum level for sustaining the desired productivity
through optimization of the benefits from all possible sources of organic,
inorganic and biological components in an integrated manner. Integrated Nutrient Management improves soil health in long run
and reduces the demand for chemical fertilizers. It ensures the concept of
sustainability in agriculture. The benefits of Integrated
Nutrient Management approach need to be fully harnessed keeping in view the
demand of food for increasing population, dwindling supplies and increasing
cost of fossil fuels. Integrated Nutrient Management
is flexible approach to minimize the use of chemicals and maximize the
efficiency of production. The concept is for optimization of the effects of all
available sources of plant nutrients to improve soil fertility. The gap in
nutrient removal and addition can be bridged only by practicing Integrated Nutrient Management. Efficient utilization of
soil resources is crucial to agricultural production for meeting the feeding
challenges of ever increasing population of country. Increase in productivity
has trigged nutrient mining and fertilizer requirement both, which resulted in
damaging quality of soil resource and environment. Soil health management is
fundamental aspect for sustainable agricultural production. Soil organic carbon
in the form of organic matter acts as backbone of soil health. Under high input
production system (Green revolution technology) limited attention has been paid
for soil health management. Only macronutrients supply with high cropping
intensity has exhausted the soil due to negative return of plant nutrients to
soil. In traditional agriculture farm manure and cow dung had been used to
supplement the nutrient requirements. Crop production has to be increased
accompanied with maintenance of soil health. To sustain the soil health in
terms of fertility and productivity, supplementary and indigenous nutrient
sources have to be explored and need to be recycled.
Integrated Nutrient Management is based on three basic principles:
(i)
Assessment of soil
fertility and climate
(ii)
Nature of crops
not in isolation but as a part of cropping system and yield target.
(iii)
At least 30% of
total nutrient levels of NPK to be in organic form.
These principles
help in estimate the fertilizer level, form and time of application to the
crop.
Principle
components of Integrated Nutrient
Management are as:
(i)
Intensified
cropping.
(ii)
Vermicomposting/
Value added vermicomposting
(iii)
Green Manuring
(iv)
/ use of
Biomanures
(v)
Soil test based chemical fertilizers
application
(vi)
Use of Bio-fertilizers for seed treatment.
Dhaincha (Sesbania spp.) a green manure crop has long been known for its
benefits of supplying fixed atmospheric nitrogen and for its overall beneficial
effects in improving soil health. Despite known benefits the practice of green
manuring could not be adopted extensively by the farmers. The main reason for
this is non introduction of dhaincha as green manure in previous time, lack of
awareness of green manuring, emphasis on major crop production rather than
nutrition of soils particularly in Tonk district of Rajasthan in Kharif season.
More so, a farmer may not be able to practice green manuring in the traditional
manner at the cost of main crop in Kharif season. Our experiences in Tonk
district reveal that farmers are reluctant in adoption of green manuring
practice at the cost of main crop in Kharif season, because they have lack of
knowledge and techniques of green manuring.
And more so, growing period of both the crops overlap and require the
same season for growing in same time. To overcome this constrain a new concept
of “Brown
Manuring” has emerged in which Dhaincha crop is grown in rainy season
as secondary crop in main crop and after 30 days a spray of 2,4-D herbicide
(@0.5kg a.i./ha) is made in field. This practice retards the growth of Dhaincha
and helps in decaying and thereby adding organic matter in growing crop and
soil.
As the organic farming is need of the
time, Modern agricultural practices have been exhausting the nutrient supplying
capacity of soil on one hand and the disposal of huge amounts of various
biodegradable organic wastes due to modernization posing a major threat to
environmental eco-system on other hand. Among the alternatives available,
disposal into soil through recycling is more fruitful rather than other options
as the soils have high metabolic rates.
SUMMARY
The development of agriculture and
protection of ecology has been realized for achieving food security and
conservation of soil resource. Since, efficient utilization of soil resource is
crucial to agricultural production for feeding the ever increasing population
of the country. As long as human kind, as part of this system worked in harmony
with nature and used the resources for its normal sustenance damage to the
system was minimal. In traditional agricultural practices organic sources of
plant nutrient had been used to partially supplement the nutrient requirement
of soil. But, due to advanced progress in human civilization and over
exploitation of natural resources like soil, the productivity potential of the
same is getting reduced. Now a day’s Indian agriculture is facing triple
challenges of (i) doubling of the crop production,(ii) improving soil quality
and restoring degraded soils and (iii) alleviating rural poverty by value
addition and diverting population to other professions (e.g. agro based
industries). The high intensity cropping system under modern agriculture era
has triggered nutrient mining and fertilizer requirement both which resulted in
to damaging soil quality of agro-eco system. Soil health management is
fundamental aspect for sustainable agricultural production. Soil organic carbon
(SOC) in the form of organic matter acts as back bone of soil health. The
declining organic fertility of soil is rather more serious. Organic matter
present in soil being the food stock of micro organisms indirectly also
mediates various bio-chemical reactions in soil and creates favorable
environment. Under high input production system limited attention has been paid
for soil health management. Only macro nutrient supply with high cropping
intensity has exhausted the nutrient reserve of soils due to negative return of
plant nutrients to soil. The decreasing level of organic carbon in soil has
been a limiting factor due to which crops do not respond to the applied
fertilizers in soil. Crop production has to be increased accompanied with
maintenance of soil health and quality. The process of soil formation and
development in turn is influenced by several natural factors such as climate
and vegetation etc., simultaneously management practices also affect their
production potential. To sustain soil quality in terms of its fertility and
productivity organic matter recycling needs to be taken at priority.
An overview of the work done so far on
evaluation of soil quality indicators in different part of the world reveals
that soil quality assessment with regards to chemical soil quality has been in
prime focus. In the process of soil quality monitoring all the pillars of soil
quality (Physical, chemical and biological) did not get holistic deal and more
so research system did not get adequate get feedback to plan and conduct demand
driven research and also there exit a huge gap in quality of research output
required at the farmers level and that being developed. It has also been
perceived that extension system should play a pro-active role in reaching to
the farmers for getting first hand information, farmers’ perception, feedback
and develop more new appropriate methodologies for divers’ farm
environment. Further, refined technology
needs be demonstrated at farmers’ field through farmers’ participatory adaptive
research and training to farmers for fine tune these to match local conditions
and resource. Reorientation of training and demonstration strategies through
reenergized extension services will definitely play crucial role to tackle
multifaceted problems of inland soil salinity and sodicity. Therefore,
technology development and dissemination through strong extension network is
required to exploit the potential of marginal salt affected lands and areas
underlain with poor quality ground water.
Conservation
agriculture process in the form of organic farming and integrated intensive farming
system has direct bearing on soil quality. The quantum of impact may be
dependent on diversity in soil type, climate and vegetation. Intensive
agricultural activities have made soil resource deficient in their inherent
productivity. Proper nutrition of soils rather than crops is of utmost
importance in preset time and there is urgent need to develop soil health
status card covering various important visible and understandable indicators of
soil health.
**********
Ajeet Kumar
Singh. Programme Coordinator, Divyayan KVK, Ranchi,
Pankaj Saraswat. SMS
(Soil Science) KVK Banasthali Vidyapith, Tonk
No comments:
Post a Comment