Statement 1 is correct: Fertigation is a method of delivering fertilizers to crops through an irrigation system. It involves the precise application of water-soluble or liquid fertilizers directly to the root zone of plants during the irrigation process. This technique allows for the controlled release of nutrients, ensuring that plants receive the right amount at the right time.
Fertigation allows for the control of the pH of the irrigation water, which can be adjusted to the optimal level for nutrient absorption by the plants. Statement 2 is incorrect: While fertigation does allow for the efficient application of many types of fertilizers, rock phosphate is not water-soluble and therefore cannot be applied efficiently through fertigation. Statement 3 is correct: Because fertigation delivers nutrients directly to the root zone of plants, it increases the availability of nutrients to the plants. Statement 4 is correct: Fertigation allows for the precise application of nutrients, which reduces the risk of nutrient leaching. Therefore, options 1, 3, and 4 are correct.