gen-state-soil-nutrient-cycles-npk-precisely-and-explain-why-it-49cf

State soil nutrient cycles (NPK) precisely and explain why it matters in 2-3 sentences.

# Soil NPK Cycles **Nitrogen (N):** Atmospheric N₂ → fixed by bacteria/lightning into NH₃/NH₄⁺ → taken up by plants → decomposed back to soil → nitrified to NO₃⁻ → denitrified back to N₂ gas **Phosphorus (P):** Weathered from rocks as PO₄³⁻ → absorbed by plants → returned via decomposition → can bind tightly to soil particles or leach away **Potassium (K):** Released from mineral weathering as K⁺ → absorbed by plant roots → returned through decomposition → held on soil particles or leached ## Why It Matters These cycles determine crop productivity and food security, as NPK are the three most limiting nutrients for plant growth—nitrogen for proteins/chlorophyll, phosphorus for DNA/ATP, and potassium for water regulation/enzymes. Disrupting these cycles through poor farming practices leads to soil depletion, requiring expensive fertilizers and causing environmental problems like algal blooms when nutrients run off into waterways.