Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

___________________________________________________________________________________Major Agronomic Practicesbecause a portion of the nutrients and organic matter in manure is broken down and released during thefirst year or two, but a portion is also held in humus-like compounds which decompose more slowly.Determining the correct amount of manure to apply is difficult. Manure samples should be analyzed fornutrient content and levels of metals such as copper, which are often present in poultry litter and pigmanure. Nitrogen available to the plant is lower than the content in the samples since some loss occursthrough volatilization (through ammonia gas NH 3) with spreading and since only a portion of the organicN becomes available to the plants through mineralization during the growing season. Also, the rate ofmanure application needed to supply the nitrogen needs of the crop will usually supply phosphorus andpotassium in amounts in excess of those the plant can use. This excess application generally does notaffect crop growth but can, in the case of phosphorus, pollute water if runoff or erosion occurs.Phosphorus runoff can be minimized by controlling erosion with cover crops or mulches (Peet, www1).Average nutrients available in manure from different sources, and from ashes are listed below .Type of manure Nitrogen (N)(%)Phosphoric acid (P 2 O 5 )(%)Potash (K 2 O)(%)cattle dung, fresh 0.3 – 0.4 0.1 – 0.2 0.1 – 0.3horse dung, fresh 0.4 – 0.5 0.3 – 0.4 0.3 – 0.4poultry manure, fresh 1.0 – 1.8 1.4 – 1.8 0.8 – 0.9cattle urine 0.9 – 1.2 trace 0.5 – 1.0horse urine 1.2 – 1.5 trace 1.3 – 1.5human urine 0.6 – 1.0 0.1 – 0.2 0.2 – 0.3Farmyard manure, dry 0.4 – 1.5 0.3 – 0.9 0.3 – 1.9Ash, coal 0.7 0.5 0.5Ash, household 0.5 – 1.9 1.6 – 4.2 2.3 – 12.0(Tata, S.N, 1992, ICAR, Handbook of Agriculture, India).In general, direct application of manure or other raw animal wastes is not recommended.Main reasons are:• Fresh manure may contain diseases that tolerate the digestive passage and may contain insectlarvae such as maggots which can destroy roots of eggplant. In fact, decaying manure may attractinsects such as maggot adults for egg laying.• Uncomposted manures are difficult to apply, not only because of their bulk, but because it is easy toapply more nitrogen than the plants can absorb. Too much nitrogen in eggplant may result instretched plants which fall over easily, and produce lots of shoots but no flowers.• Direct application can lead to problems of excess nitrates in the plant and runoff of nitrates intosurrounding water supplies.• Excessive raw manure can burn plants and lead to toxic levels of nitrates in leafy greens.• Decomposition process will consume oxygen from the soil; this oxygen is also needed by plant roots.One case where this process may be tolerable is described in section 3.10.1.5 on soil sterilization ofnurseries.• Decomposition process produces methane, a gas harmful to plant roots. Also see section 3.10.1 onsoil sterilization of nurseries.• Regular supply of fresh manure leads to lower soil pH.3.8.3.4 Organic mulchesMulch is any material placed on the soil surface to protect the soil from the adverse effects of rainfall,wind, and water loss. Mulches are also used to control weeds and reduce erosion. Organic mulchingmaterials will break down over time, contributing organic matter to the soil. The use of mulches for weedcontrol is discussed further in chapter 9 on Weed Management. Furthermore, as mulch reduces the needfor tillage, plowing labor is reduced.Many kinds of organic materials can be used as mulch including tree leaves, grasses, crop residues (butonly those free of diseases and insect pests!), saw dust, rice straw, etc. Even weeds (without seeds),coconut leaves, water hyacinths and compost can be used as mulch.29Eggplant Ecological Guide