Life on the soil owes to life in the soil

The health and quality of soils is dependent on the mix of living organisms they contain which is represented by the term soil biodiversity. 

Soil biodiversity reflects the variability among living organisms including a myriad of organisms not visible with the naked eye, such as micro-organisms (e.g. bacteria, fungi, protozoa and nematodes) and meso-fauna (e.g. acari and springtails), as well as the more familiar macro-fauna (e.g. earthworms and termites).

These diverse organisms interact with one another and with the various plants and animals in the ecosystem forming a complex web of biological activity. Soil organisms contribute a wide range of essential services to the sustainable function of all ecosystems. They act as the primary driving agents of nutrient cycling, regulating the dynamics of soil organic matter, soil carbon sequestration and greenhouse gas emission, modifying soil physical structure and water regimes, enhancing the amount and efficiency of nutrient acquisition by the vegetation and enhancing plant health. These services are not only essential to the functioning of natural ecosystems but constitute an important resource for the sustainable management of agricultural systems.

Few facts on soil biodiversity

Nowhere in nature are species so densely packed as in soil communities. Soil biodiversity is characterized by:

• Over 1000 species of invertebrates may be found in a single m² of forest soils.
• Many of the world’s terrestrial insect species are soil dwellers for at least some stage of their life-cycle.
• A single gram of soil may contain millions of individuals and several thousand species of bacteria.
• A typical, healthy soil might contain several species of vertebrate animals, several species of earthworms, 20-30 species of mites, 50-100 species of insects, tens of species of nematodes, hundreds of species of fungi and perhaps thousands of species of bacteria and actinomycetes.
• Soil contains the organism with the largest area. A single colony of the honey fungus, Armillaria ostoyae, covers about 9 km2.

PDS Organic Spices actions

Since Idukki district is situated on the Western Ghats and it has very steeply terrain, the major problem here is soil erosion and nutrient loss due to leaching. Also the pollution of soil by the usage of chemical pesticides and synthetic fertilizers leads to the depletion of soil quality, its water holding capacity and loss of soil microbial population. The monoculture system and loss of forest ecosystem also impacts the health of soil eco system.

A survey by the government of Kerala shows that Majority of soils (74 %) in the region are very strongly to strongly acid with overall pH ranging from 4.5 to 5.5. Organic carbon comparatively is high in the region. Available phosphorus, Boron & Magnesium is low in majority of the areas.

Since production and yields of spices heavily dependent on the quality of the soil the soil quality management is found to be an important driver for PDS Organic Spices business with respect to biodiversity aspect. The focal point of our farming activates is to build up good soil carbon content and thus enable an environment where soil biota can grow and flourish. Management of soil organic matters is being done though the incorporation of cover crops, addition of compost, vermi-compost and biodynamic composts, Cow horn manure and local traditional knowledge-based manures.

Basically PDS Organic Spice’s farmer community is practicing intercropping and crop rotations. They are growing of cover crops like Pueraria, Mucuna, Sesbania, Crotalaria and other locally available leguminous species to prevent soil erosion and to harvest free atmospheric nitrogen into soil as well as to conserve soil moisture.

PDS Organic Spice’s has a soil, plant and water testing laboratory which enables the farmers to test their soil, water and plant on free of cost. Based on the test results, we are issuing soil health cards to the farmers. This enables the farmers to monitor the status of their soil and do the necessary conditioning in the soil.

Regular trainings are imparting to the farmers on the importance of soil health, and how to evaluate the status. Soil sampling techniques are demonstrated to every farmer.

We encourage them to plant vetiver plants though the contours to stabilize the soil, prevent soil erosion and fix micronutrients to the soil.

The farmers enrich all the plant base with local strains of Arbuscular Mycorrhizae as well as native soil microbes enriched cow dung based organic liquid manures like kunapajala, Jeevamrutham and others through women entrepreneurships

Also, the producers are keeping records of how much fertilizer they applied at each application. This is recording in the Planning & Record Book of every individual plot.

The impacts

When comparing organic carbon content of different soils of Idukki district is with organic and non-organic fields, it is found that in non-organic farms the organic carbon content is high in 55% of the farms whereas the samples from organic farms shows that the organic carbon content is high in 77% of the farms. In non-organic farm samples, the organic carbon content is reported low in 16%, but from organic farm it is 2% only. From these results it is evident that the organic farm management and soil management practices generally increases the organic carbon content in the soil. This creates a favorable soil ecosystem for the microorganisms to live in and thus increases the microbial diversity in the soil. It also improves soil aeration (oxygen in the soil) and water drainage and retention, and reduces the risk of erosion and nutrient leaching. Soil organic carbon is also important to chemical composition and biological productivity, including fertility and nutrient holding capacity of a field. As carbon stores in the soil increase, the risk of loss of nutrients through erosion and leaching is reduced. When soil is eroded, the carbon in soils is lost in the form of greenhouse gasses (GHGs), contributing to climate change. An increase in soil organic carbon typically results in a more stable carbon cycle and enhanced overall agricultural productivity.

Carbon Sequestration

Carbon sequestration is the long-term removal, capture of carbon dioxide from the atmosphere to reverse atmospheric carbon dioxide pollution. Trees, grass and other plants play a major role in this process as they use carbon dioxide for the photosynthesis process.

Organic Farming is complimented the Carbon Sequestration because it focus on improving the soil organic matter content, increasing biodiversity in the farms, inter cropping and crop rotation systems. This soil organic matter and floral, faunal and microbial diversity in the organic farms play important role in increasing the carbon sequestration and thereby reducing the chance for global warming. This is another important ecosystem service provided by the organic farmers.

As part of the PDS-PBAB project, Carbon sequestration in each of the farmers is being estimated using tool suggested by IBBI. To calculate carbon sequestration, the height and width of total number of trees in fields is noted and calculated as per the IBBI scale. Carbon content in trees increases with the increase in height and width of the trees. It is calculated in the unit of kilogram (Kg). We are using this document to set the objectives of our biodiversity action plan.