Plastic mulching for vegetable production

Dr Laishram Kanta Singh, Mrs K Lily Rangnamei and Dr S Roma Devi
It has become essential for us to produce more and of higher quality produce in order to compete in the global market due to the rising demand for horticulture products and people’s increased awareness of their health. In addition to adopting high yielding varieties and sound agricultural methods, it is necessary to use environmental and biological energy to increase productivity. Utilizing natural resources wisely and economically with low-cost technologies is flexible. Mulch has recently emerged as one of the most efficient technologies for improving crop quality and yield while also lowering production costs because it is a natural resource. The German word “molsch,” which means soft and beginning to decay, is likely the source of the English word “mulch,” which is thought to be a reference to gardeners. Mulching is the method or practise of covering the soil/ground in order to improve plant growth, development, and crop production efficiency. The precise definition of mulch is “coating of soil.” While organic mulches like compost, leaf, straw and dead leaves have been utilised for generations, the methods and advantages of mulching have changed over the past 60 years with the introduction of synthetic materials. The available research and field data on the effects of synthetic mulches has created a substantial quantity of useful information. Comparatively speaking to other mulches, plastic mulches are entirely impermeable to water; as a result, they restrict water losses and soil erosion over the surface and prevent direct evaporation of moisture from the soil. It contributes positively to water conservation in this way.
A prepared seedbed is covered with synthetic mulches, such as landscape fabric or black polyethylene film (the most popular type of plastic mulch), right before a vegetable crop is transplanted or seeded through holes or slits cut into the mulch. Under the mulch, in-row drip irrigation systems irrigate the crop while also dispensing liquid fertilisers. Mechanization enables the farmer to mulch and plant a multi-acre field in a single day using tools like tractor-drawn bed shapers, mulch layers, and planters. Infrared-transmitting (IRT) mulch, black plastic, and other opaque materials successfully prevent weed development while promoting soil warming and early crop emergence. Alleys between mulched beds typically require cultivation or other weed control measures, and weeds that emerge via planting holes may need to be manually removed.
Advantages of plastic mulching
· It is completely impermeable to water.
· It prevents the direct evaporation of moisture from the soil and thus limits the water losses and conserves moisture.
· By evaporation suppression, it prevents the rise of water containing salts.
· Mulch can make applying fertiliser easier and lessen the amount of plant nutrients that are lost through leaching.
· Mulches can also act as a defence against soil diseases.
· Annual weeds’ germination is prevented by opaque mulches.
· Certain insects will be repelled by reflective mulch.
· Mulches maintain a warm temperature throughout the night, allowing seeds to sprout quickly and young plants to swiftly form a robust root system.
· Mulches made of synthetic materials are crucial to the solarization of soil.
· Due to the increased degree of microbial activity, mulches create a microclimate beneath the surface that is higher in carbon dioxide.
· Under mulch, the soil structure is maintained during cropping period.
· Early germination almost 2-3 days.
· Better nodulation in crops like Groundnut.
· Less nematodes population.
· Water erosion is completely averted since soil is completely covered form bearing action of rain drops.
· When compared to organic mulches, it serves for a longer period.
Types of plastic materials
Several distinct plastic films made of various polymer kinds have all been examined for mulching at various points throughout the 1960s. Although there were some slight variances in their technical performance, LDPE, HDPE, and flexible PVC have all been employed. Polyethylene is preferred because of its higher permeability to long wave radiation, which can raise the temperature around plants at night. Because it is more practical to utilise, the vast majority of plastic mulch produced now is made of LLDPE.
Importance parameters of the plastic film
With the exception of when it is used for solorization, the film’s thickness often has no impact on the mulching effect. However, several recent references do show how crop output is impacted by film thickness. Since it is sold by weight, it is desirable to choose a film that is as thin as possible, but proper consideration should also be given to the film’s durability. Early mulch films had a thickness of 60–75 microns (240–300 gauge), however with to advancements in film extrusion technology, it is now possible to produce 15 micron thick films. These films are weak mechanically, as evidenced by how easily they tear when tension is applied.
Precautions for Plastic Mulch Laying
· The film shouldn’t be stretched too tightly. It ought to be flexible enough to withstand the conditions of expansion and contraction brought on by changes in solar temperature and the effects of cultural operations.
· Black film should have more slack since this colour exhibits the greatest expansion and contraction phenomena.
(To be contd)