Ongoing soil potassium depletion under intensive cropping in India and probable mitigation strategies. A review

Abstract

Potassium (K) is essential for plant growth and vital for soil health. However, despite high crop demand, K fertilization continues to be ignored or severely inadequate in Indian agriculture. Over time, this could lead to severe depletion of soil K reserve, irreversibly alter K-bearing minerals, and adversely affect soil fertility and crop productivity. Hence, we should comprehensively assess the alarming situation of soil K mining in India and come up with appropriate solutions. Keeping the above in mind, here we review the soil K pools concerning plant availability, their contents in major soil orders of India, reasons and status of soil K mining under major crops and cropping systems in India, and the impact of long-term K mining on soil K pools and clay minerals. We also address various aspects of sustainable K management in agriculture and suggest future action courses focusing on India. Our main findings are: (i) farmers in India mainly apply nitrogen and phosphorus, but little or no K; consequently, (ii) net K balance continues to be negative for most crops and cropping systems across India (e.g., -3.29 million tonnes [Mt] in 2000-01, -7.2 Mt in 2015-16); (iii) long-term K mining primarily depletes the exchangeable and non-exchangeable K pools in soil, and alters clay minerals to various extents; and (iv) the existing K fertilizer recommendations need an upward revision. We further enlist indigenous non-conventional alternatives of K fertilizers to meet the agricultural K demand. This is the first comprehensive review to simultaneously address the ongoing soil K mining in India, its impact, and its potential mitigation strategies. The points raised here would help reduce soil K mining, plan research work, and make policy decisions on K fertilization and residue management with the ultimate goal to prevent soil health deterioration and ensure sustainable crop production.

Combining Fuzzy, Multicriteria and Mapping Techniques to Assess Soil Fertility for Agricultural Development: A Case Study of Firozabad District, Uttar Pradesh, India

“…The study region is a part of the IGP tract and the soils share their origin with alluvium sediments. Alluvial soils present in the IGP tract have a large amount of mica/illite clay minerals in clay and silt fractions, thus providing a very large reserve of K to the soil [47,48]. As far as the DTPA-extractable micronutrients content in soil is concerned, all the soils were found to be sufficient in Cu (2.86 mg kg −1 (average); 0.6-4.88 mg kg −1 (range)), while approximately 75% of the samples were deficient in Fe (4.74 mg kg −1 ; 1.20-20.9 mg kg −1 ), Mn (2.66 mg kg −1 ; 0.14-12.3 mg kg −1 ), and Zn (0.63 mg kg −1 ; 0.21-3.00 mg kg −1 ) content.…”

Sustainability of Organic Farming from a Global Perspective: A Critical Analysis of Soil Types and Fertility Status of Organically Managed vs. Chemicalized Vegetable Fields of South India

“…SAK over organic and chemicalized elds amount of SAK in soils is crucial to plant growth and productivity. Insu cient application of K into soils and lack of proper monitoring of K in agricultural soils have been causing detrimental effects on both soil fertility and long-term crop productivity in the Indian elds (Das et al, 2022). The high price of chemical fertilizers and the low K use e ciency in tropical soils remain signi cant hurdles to the optimum supply of K in such elds (Basak et al, 2023).…”

Effect of NPK Fertilizers, Farmyard Manure (FYM) and Bio-fertilizers on Quality Parameters of Onion (Allium cepa L.) Grown in Jaipur, Rajasthan

“…It needs to be used with caution by alleviating consequent hazards in soil with the help of supplemental organic manuring. Continuous use of inorganic fertilizers has depleted soil organic matter, resulting into inherent loss of native soil N, available P, available K and ultimately lowered the productions [16]. The repeated and excessive application of chemical fertilizers is harmful to the plants.…”