What are the advantages of fertigation in agriculture? 1. Controlling the alkalinity of irrigation water is possible. 2. Efficient application of Rock Phosphate and all other phosphatic fertilizers is possible. 3. Increased availability of nutrients to plants is possible. 4. Reduction in the leaching of chemical nutrients is possible. Select the correct answer using the code given below:

1. Statement 1 is correct. Fertigation systems allow for the injection of acids into the irrigation water, which makes it possible to control or reduce the alkalinity and manage the pH of the water delivered to crops, improving nutrient uptake. 2. Statement 2 is incorrect. Fertigation requires nutrients to be in soluble form. Rock Phosphate and many other common phosphatic fertilizers have very low water solubility, making their efficient application through typical fertigation systems difficult or impossible. 3. Statement 3 is correct. By delivering dissolved nutrients directly to the root zone along with water, fertigation ensures that nutrients are readily available for plant uptake, leading to increased availability compared to traditional methods where nutrients might get fixed in the soil. 4. Statement 4 is correct. Fertigation allows for precise control over the amount and timing of nutrient application, matching it closely to the plant's needs. This minimizes excess application and significantly reduces the leaching of chemical nutrients below the root zone, thus preventing groundwater contamination and improving nutrient use efficiency. 5. Therefore, statements 1, 3, and 4 represent the advantages of fertigation in agriculture.