water moves from the root to the leaves because long-distance water movement is crucial to the survival of land plants. Although plants vary considerably in their tolerance of water deficits, they all have their limits, beyond which survival is no longer possible. About 85 percent of the fresh weight of leaves can be water. On a dry, warm, sunny day, a leaf can evaporate 100 percent of its water weight in just an hour. Water loss from the leaves must be compensated for by the uptake of water from the soil. Water transport is also important for the uptake of essential mineral nutrients from the soil. Shortages of mineral nutrients such as nitrogen, potassium, and phosphorus are often limiting to plant growth, which is why fertilizers are often added to the soil to improve plant productivity and appearance.