Question: query about mulching.
Answer: mulching: mulching means to cover the soil between plants with a layer of material. it keeps roots and bulbs cool in summer and warm in winter.
ordinary veld grass also makes a very good mulch, as do leaves, soft cuttings, seaweed, straw, tree bark and manure. mulching prevents water from evaporating. less watering is therefore needed. it protects the soil from wind, rain and sun, and suppresses weed growth by blocking out sunlight. the irrigation water or rainfall either moves into the soil thru-holes on the mulch around the plant area or through the un-mulched area. 
types of mulch film:
                             ldpe, hdpe and flexible pvc have all been used and although there were some technical performance differences between them, they were of minor nature. owing to its greater permeability to longwave radiation which can increase the temperature around plants during the night times, polyethene is preferred. today the vast majority of plastic mulch is based on lldpe because it is more economic in use.