Renu Fandan, S. K. Dhankhar and Pooja Pahal
Department of Vegetable Science 
Chaudhary Charan Singh Haryana Agricultural University, Hisar

The term "mulch" is derived from the German phrase "mulch," which meaning "soft to decay," and refers to the usage of organic materials and agricultural wastes (such as straw, grass clippings, compost, and leaves) spread over the ground as mulch. Mulch is a naturally or artificially spread layer of plant leftovers or other substances on the soil's surface. The primary goals of mulching in agriculture are moisture conservation, temperature regulation, surface compaction prevention, runoff and erosion reduction, soil structure development and weed control. Organic mulches reduce soil erosion and moderate soil temperature, offer nutrients to plants as it slowly composts, providing plants with season-long feeding, and benefit the landscape by directly defeating pathogens and pests, enhancing beneficial species, and neutralising pollutants. It acts as an insulator, cooling and regulating soil temperatures during hot days and cold nights. It boosts good bacteria activity and aids in illness prevention. It also prevents evaporative loss of moisturefrom the field. Evaporation from the soil surface accounted for 25-50% of total crop field evapotranspiration. Mulching with agricultural waste such as straw, compost, grass clippings and leaves etc. boosted water retention and prevented soil evaporation. Furthermore, mulching practises help to restore soil health by providing a favourable environment for earthworms and other beneficial microorganisms to develop on the soil. Weed seedlings cannot live in a mulched environment, which eliminates the need for chemical weedicides.

Type of Organic mulches and their benefits
Organic mulches are materials of natural origin that decompose naturally, such as agricultural wastes used as mulch which includes bark chips, grass clippings, wheat or paddy straw, plant leaves, compost, rice hulls, and sawdust. It degrades over time and increases the soil's water holding capacity. As it decomposes, it releases nutrients into the soil. It also indirectly improves water efficiency. A mulched layer inhibits weed development by preventing light penetration to the soil surface. Reduced weed prevalence improves water use efficiency substantially. However, among organic materials, there are numerous options, each with unique properties and adaptability for distinct growing situations.

1. Bark: These are effective mulch materials because they hold more moisture, retain it for longer periods of time, and aid in the provision of moisture to the growing crop. It is often used for vegetation and landscaping, however because it is acidic, it should be avoided in vegetable fields. However, these mulches are ideal for covering the walkways between the beds. There are two kinds of bark mulch: hardwood and softwood.

2. Grass Clipping: In Indian agriculture, grass clipping is one of the most simply and abundantly available mulching materials. Fresh grass clippings degrade quickly in the field, increasing the quantity of nitrogen in the soil. There are many various types of grass clipping available, including green, fresh, and dry grass. Green grass clippings are typically not employed during the wet season because they may promote the establishment of their own root systems, which is detrimental to crop growth. Green clippings can generate a lot of heat and potentially harm plants. As a result, dried grass is always preferable as mulch. Apply the product to a depth of 2-3 inches.

3. Dry Leaves: When utilised as mulch, leaves are useful to the soil because they give nutrients. It is often utilised in natural forest regions with plenty of trees. Dry leaves are cheaply and abundantly accessible, and composted leaves create superior mulch. However, because dried leaves are scarce in the spring, they are valued as overwinter mulch. Small branches and wood barks are placed over the dried leaves mulch to prevent them from blowing away. The thickness of the dry leaf mulching is around 3-4 inches.

4. Straw: Straw is good for mulching because it is quickly placed in the field, stays in place, and reflects sunlight, which helps some vegetables develop fruit. It is utilised in vegetable fields for winter protection as well as summer mulch. These mulches are excellent for insulation, water penetration, and weed control. The most significant advantage is that it does not contain weed seeds. The straw mulching is around 6 to 8 inches thick.

5. Compost/Manure: Compost is an excellent mulch and soil conditioner that may be easily made at home by composting various waste items such as leaves, straw, grass, and plant wastes. It improves soil qualities such as physical, chemical, and biological aspects, as well as the carbon content, which increases the soil's water retention capacity. Compost is an excellent ingredient for boosting soil health. Compost is a wonderful addition to bed preparation or as a thin 'top dressing' in the early part of the season. Apply 3 to 4 inches deep.

6. Sawdust: Sawdust is a common sort of mulch in regions where it is readily available. It is discovered after wood finishing operations, has lower nutritive properties, and contains half the nutrients of straw. The breakdown occurs relatively late due to the high C: N ratio. Its decay will generate a nitrogen deficiency in the soil, thus regular fertiliser application is required. Because of its acidic nature, it should not be utilised in acidic soils.

7. Newspaper: Newspaper mulching is an inexpensive way to suppress weeds. The newspaper layer biodegrades quickly into the soil. Newspaper is preferable than plastic since it decomposes over time. In fields where weeds have already developed from the previous season and fallen seeds will germinate in the coming season, newspaper mulch can save a lot of time and work. However, in high-wind zones, the use of newspaper mulches is discouraged. Glossy paper should be avoided in vegetable fields since the ink may leech into the soil.

8. Seaweed: If picked fresh, seaweed provides an excellent mulch that adds minerals to the soil. Because seaweed shrinks significantly when it dries, a thick coating should be put on the field. Before applying seaweeds in the field, they should be sprinkled with fresh water to reduce the amount of salt in the soil.

9. Cocoa Bean Hulls: It's a good mulching material for improving soil fertility. It is rich in nitrogen, phosphate, and potassium. It has a pH of 5.8 and is acidic in nature. It is utilised in landscaping because of its pleasant odour and appealing appearance.

10. Corncobs (Crushed): It is yet another excellent and inexpensive mulch resource. Corncob mulch can be coloured to improve its look and used in landscaping.

11. Mushroom Compost: It is an organic plant fertiliser that is commercially available in regions where it should be planted. It is sold in the market as spent mushroom compost/spent mushroom substrate. Because of its high nutrient content, it improves soil fertility.

12. Peanut Hulls: It is a visually appealing mulch that is found near peanut processing locations. Farmers are also utilising the abundant crop wastes available in the field as mulch.

13. Hops (Spent): This mulching material was bought cheaply and collected from nearby breweries. They have a nice appearance and do not burn easily. It has a strong scent, but it should be used after half a year or more.

Advantages of Organic Mulch: 
The mulch layer reflects the most sunlight; otherwise, sunlight heats the soil. It keeps the soil temperature at its optimal level. The rate of evaporation from the soil surface was slowed due to the avoidance of direct solar radiation penetration. Mulch layer also inhibits weed growth because when soil is covered with mulch layer, light does not reach the soil surface. It also keeps the soil surface from eroding due to high-speed wind and surface runoff. It also reduces rainwater runoff and increases the amount of water infiltration, indicating more available soil moisture for plant usage. It improves the physical, chemical, and biological properties of the soil. These mulches breakdown slowly and increase organic content in the soil. These organic components provide nourishment for the soil's beneficial earthworms and other microorganisms.Organic mulches also boost the organic carbon content of the soil. It allows for improved root penetration, root development, and nutrient extraction from a deeper layer of soil. Organic mulches attract the majority of the soil's beneficial microflora, which act on degradable wastes and aid in the release of plant nutrients.

Limitations of Organic Mulch: 
It has numerous advantages, but it also has some drawbacks, including as keeping the soil too moist on poorly drained soils and restricting oxygen in the root zone. If it is applied close or in contact with the stem, the stored moisture provides an environment conducive to disease and pest growth. Many organic mulches serve as breeding grounds for a variety of insects and pests. Mulches like hay and straw carry seeds that can grow into weeds. These organic mulches are easily biodegradable and can only be used for a limited time.