COLE stands for the Coefficient of Linear Extensibility. It is also referred to as the potential volume exchange or swell index. This metric provides a quantitative expression used to classify soils based on their shrink-swell potential. Understanding this value is essential for both civil engineering projects and various agronomic applications where soil stability is a critical factor for plant growth and infrastructure development.

Gypsum is widely used in Rajasthan to reclaim alkaline soils. The calcium in gypsum replaces exchangeable sodium on the soil colloids, which is then leached out, helping to lower the soil pH and improve physical structure. While alkaline soil issues exist in various regions, Rajasthan has significant deposits of gypsum and extensive areas where this amendment is critical for maintaining agricultural productivity in sodic soil conditions.

Serpentine is a group of minerals formed through the serpentinization process, which involves the low-temperature metamorphism of ultramafic rocks. These minerals are characteristically rich in magnesium and water, often exhibiting a greasy or slippery texture and a green coloration. The 1:1 layer structure of these minerals incorporates magnesium as a primary structural component, distinguishing them from other silicate minerals found in geological formations.

VAM fungi form a symbiotic relationship with plant roots, extending the effective root surface area through hyphal networks. This association is particularly effective at scavenging and transporting immobile phosphorus (P) from the soil to the plant. While VAM can assist with other nutrients, its most significant and well-documented contribution is the increased uptake of phosphorus.

Boron deficiency in plants can be effectively managed by applying various boron-containing fertilizers. Boric acid, Solubor, and Borax are all recognized sources of boron that provide the nutrient in a form accessible to plants. Depending on the soil type, crop requirements, and application method, any of these compounds can be used to rectify the deficiency and support healthy plant growth and development.

Equivalent moisture is a laboratory measurement used to estimate the field capacity of a soil. By applying a centrifugal force of 1000g, the water held by capillary forces is measured, providing an approximation of the water content that the soil can retain against gravity.

Arkose is a type of sedimentary rock, specifically a sandstone, that contains at least 25% feldspar. It typically forms from the rapid weathering and erosion of granitic rocks, where the feldspar has not had sufficient time to weather into clay minerals. The presence of significant quartz and feldspar, often with minor amounts of mica, distinguishes arkose from other sandstones, providing clues about the geological history and the source rock of the sediment.

The lithosphere is the rigid, outermost shell of a terrestrial-type planet or natural satellite. On Earth, it comprises the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater. It is the solid, rocky layer that provides the foundation for soil formation and terrestrial ecosystems.

Essential plant nutrients are categorized based on the quantity required by plants. Macronutrients, such as nitrogen, phosphorus, and calcium, are needed in relatively large amounts. Conversely, micronutrients are required in trace amounts but are equally vital for physiological processes. Zinc, along with boron, manganese, copper, molybdenum, iron, and chlorine, is classified as a micronutrient because it is essential for enzyme activation and overall plant development despite the small quantities needed.

The Fertilizer Control Order (FCO) is a regulatory framework promulgated under the Essential Commodities Act of 1955. It mandates strict quality, trade, and distribution standards for fertilizers. Any product not explicitly listed in the FCO schedule lacks legal recognition as a fertilizer, meaning it cannot be marketed or sold under that designation to ensure farmers receive standardized, quality-controlled agricultural inputs.