Healthy soil critical to human health and for achieving SDGs

Soil research must focus both on technology development and implementation
The ability of soils to support soil functions or services is decreasing (Image: Katrin Park/International Food Policy Research Institute)
The ability of soils to support soil functions or services is decreasing (Image: Katrin Park/International Food Policy Research Institute)

Although India attained self-sufficiency in food production, realising zero hunger, good health, and no poverty remains a challenge. In this paper ‘Soil health and its relationship with food security and human health to meet the sustainable development goals in India’, the authors summarize key features of Indian soils and capture existing and developing trends in soil research in India to assess our preparedness to meet soil-linked sustainable development goals (SDGs).

Soil research in India has largely focussed on a) evaluating soil as an important natural resource through soil survey and mapping, b) developing soil test crop response (STCR)-based fertilizer recommendations with a goal to achieve higher crop yields and improved nutrient use efficiency, and c) improving irrigation efficiency through the efficient management of soil water regimes. Some of the contemporary efforts have started to treat agricultural production systems as an integral part of the critical zone.

This paper published in the journal Soil Security begins by taking a stock of Indian soils, their quality and nutrient status and explored some of the rapidly emerging areas of soil research to realize this goal. India has 11 major soil groups with more than 72% of its 329 Mha geographical area covered by alluvial, red, and black soils. As many as 8 different soil orders are found in our country. Measured soil parameters across the country at 1:250000 scale suggest that the first and third quartiles range from 18 to 54% for sand contents, 22 to 48% for clay contents, 5.8 to 7.9 for soil pH, and 0.20 to 0.66% for soil organic carbon (SOC) contents.

In general, the SOC stock for Indian soils is low and low cation exchange capacity (CEC) values coupled with low water holding capacities make Indian soils to have poor soil quality. Some of the strategies to build SOC stock includes the addition of farm yard manure (FYM) or other green manures, inclusion of legume-based cropping systems, growing of horticultural crops, improved cultivation practices such as zero tillage, and addition of crop residues among others.

Continuous addition of micronutrient-free NPK fertilizers and indiscriminate use of irrigation water during the post-green revolution period have caused micronutrient and secondary nutrient deficiencies in many Indian soils. Large scale soil testing efforts in farmers’ fields in 12 different Indian states revealed that almost 74% of agricultural soils require soil amendments.

In fact, major focus on nitrogen phosphorus potassium (NPK) application by farmers without adequate soil testing has created nutrient imbalance in many agricultural fields resulting in decreasing use efficiencies for major plant nutrients. The ability of soils to support soil functions or services is decreasing, thereby, creating large yield gaps between the achievable potential and farmers’ harvested yields. Unless the targeted nutrients are available in soil, even the bio-fortified crop cultivars will have low nutrient contents adversely affecting human and animal health. 

Percentages of soil samples showing different ranges of soil pH and deficiencies in soil organic carbon (SOC) and different nutrient contents in farmers’ fields samples collected from selected states of India (AP: Andhra Pradesh, GJ: Gujrat, JH: Jharkhand, KA: Karnataka, KL: Kerala, MP: Madhya Pradesh, MR: Maharashtra, OD: Odisha, RJ: Rajasthan, TN: Tamil Nadu, TS: Telangana, and UP: Uttar Pradesh).

Smallholder farms in India need new agricultural technology and their efficient delivery to farmers. Over the last decade, there have been ambitious Government programmes such as national soil health card mission and rapidly changing agricultural research ecosystem to promote smart sensing, robotics, remote sensing to name a few. The realization that farmers are to be associated with soil research and development, as is done in soil health card mission and public-private partnership such as Bhoochetna, sets in a new trend to enable the country and its citizens self-reliant.

Meeting SDGs of no poverty, zero hunger and well-being, and achieving food security through climate resilient and sustainable development becomes a daunting task. Specifically, land use planning and sustainable management of soils require innovative approaches and involvement of multiple stakeholders for meeting SDGs. Thus, there is a need to evaluate existing trends in soil research and development in India.

Moreover, research on new technologies in form of rapid and non-invasive sensing, internet of things (IoTs), digital soil mapping (DSM), and remote sensing approaches are also being initiated to make digital agriculture a reality. Furthermore, agricultural startup ecosystem is also rapidly changing in India.

The overarching goal of this review is to summarize key features of Indian soils and capture existing and developing trends in soil research in India. We present salient features of Indian soils and their carbon footprint across different agroecological regions (AER), nutrient status and soil health, and opportunities in soil research and education in India. Salient experimental results on these critical soil aspects are described to assess our preparedness for meeting SDGs.

Preparedness for meeting SDGs

With the UN declaration of 2015 as the international year of soils, we recognize the connection between soils and SDGs. Fortunately, several national efforts are underway. For instance, the current efforts of soil health card mission, more crop per drop of water, carbon sequestration, and doubling of farmers’ income are expected to generate holistic solutions. The emphasis must be on providing demand-driven solutions to farmers with economic benefits while protecting our environment.

Researchers must work with policy makers, extension staff, and farmers to highlight the benefits of soil science. Although fertility remains a crucial issue, soil science research should also explore and improve the use of organic fertilisers. There is a need to popularise integrated nutrient management and convince farmers that only organic or zero budget strategies will not feed the 1.34 billion population. The onus is on research managers to liaise with the policy makers, extension staff, and farmers and demonstrate the benefits of integrated nutrient management holistically to meet the SDGs.

Under the NITI Aayog, Government of India has constituted the Development Monitoring and Evaluation Office (DMEO) for monitoring and implementing the SDGs. An SDG India Index was launched in 2018 to monitor the progress of the implementation of SDGs made by the states and union territories (UT) in the country. Recently, a third edition of the SDG India Index was released for 2020-2021.

The index provides goal scores ranging from 0-100 with the high goal score being the distance a state or UT has reached towards the targets set for 2030. Based on the scores, states and UTs are classified into four different categories: Aspirant (0-49), Performer (50-64), Front Runner (65-99) and Achiever (100). A composite score is calculated for each state and UT by taking the mean of the individual goal scores.

The state of Kerala tops in the country with a composite SDG score of 75 followed by 74 for Himachal Pradesh and Tamil Nadu. For the SDG2 (End Hunger, Achieve Food Security and Improved Nutrition, and Promote Sustainable Agriculture, United Nations, 2015), the national score was 47 in 2020, which is low. Specifically, eleven states and two UTs fall behind the country's score of 47 making it difficult to achieve its target by 2030.

In case of food subsidy, the country has covered 99.51 % of beneficiaries under National Food Security Act 2013 in 2019-20 (NITI Aayog, 2021). The target 2.2 of SDG2 aims at ending all forms of malnutrition.

As per the CNNS Report 2016-18, 33.4% of children under five years are underweight and the target has been set to reduce it to 1.9%. The target 2.3 of SDG2 aims to double the productivity of rice and wheat to 5322.08 kg/ha by 2030, from the base year of 2015-2016. Only Punjab and Haryana are nearing the target with productivity of 4693.24 kg/ha for rice and 4272.42 kg/ha for wheat in 2018-2019 (NITI Aayog, 2021).

Summary and outlook

Thus, there is an urgent need to reverse this land degradation trend. Fortunately, there are national strategies being developed to double farmers’ income by focusing on development initiatives including infrastructure, technology, policy, and institutional mechanisms (Chand, 2017).

Specifically, the government has launched key development programmes to support farmers and related stakeholders such as Pradhan Mantri Krishi Sinchai Yojana (PMKSY), Paramparagat Krishi Vikas Yojana (PKVY), Pradhan Mantri Fasal Bima Yojana (PMFBY), and soil health card mission to strengthen irrigation, traditional agriculture, crop insurance, and soil testing, respectively.

The doubling farm income committee has recommended seven action plans to increase farm income in India: (i) increase in productivity of crops, (ii) increase in productivity of livestock (iii) improvement in efficiency of input use (cost saving), (iv) increase in crop intensity, (v) diversification towards high value crops (vi) improved price realization by farmers and (viii) shift of cultivation to non-farm jobs.

There is also a call for developing transformative technologies such as sensor-based assessment of soil parameters and soil processes. Fortunately, soil research on nutrient transport, digital soil mapping, different remote sensing methods, and modelling of agricultural systems in critical zone framework has already been initiated over the last two decades.

While these new research areas should be strengthened, there is also a need for strengthening the knowledge delivery system using innovative methods such as para-extension workers (lead farmers and farm facilitators), new information technology tools like apps, decision support systems in local languages to reach to a large number of small farm-holders.

There is also a need to build partnerships amongst researchers, policy makers, and development workers including extension agents, small farm-holders and inputs suppliers. Thus, the paper emphasizes that soil research must focus both on technology development and implementation such that technology remains relevant to farmers.

The full paper can be accessed here

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