Preventing Water Losses by Mulching and Cultural Practices

Introduction

The water requirement of crops in that quantity of water required by the crops within a given period of time for their maturity and it includes losses due to evapotranspiration plus the unavoidable losses during the application of water and water required for special operation such as land preparation, puddling and leaching. Irrigation is an important practice for higher production both in mono and poly cropped areas. Effective irrigation is the controlled and uniform application of water to crop land in the required amount at required time with minimum cost to produce optimum yields without the waste of water and any adverse effect on the soil in the form of soil salinity and water login problems. The misuse of water leads to the problem of water logging and salt imbalance thus rendering agricultural lands unproductive or less productive of problematic. As the source of water to crop land is the rainwater and supplementary through irrigation. Hence for effective use of water it is necessary to avoid water losses therefore control measure are taken for both rainwater and irrigation.

Preventive Measures

• Mulching

Surface mulches are used to prevent soil from blowing and being washed away. It also breaks the surface crust, which forms after each downpour. Mulching with different materials e.g. paddy husk, grass mulch, jowar stubble and wheat straw, also plastic mulches were used. Organic mulches @5t/ha are recommended, vertical mulching with jowar straw is also recommended to conserve run-off and utilize it effectively. Mulching has advantage of to keep down weeds, improve soil structure and increases infiltration.

To prevent water losses other cultural methods includes wedding, harrowing digging. To avoid water losses due to run-off strip cropping, mixed cropping, erosion permitting-resisting cropping etc. should be followed. In case of shallow and medium soil bunds may be aligned on 0.2% grade and in medium deep and deep soils on 0.3% grade. The area in between to bunds should be dressed to have uniform one-sided slope and a planned grade of 0.2 to 0.3% to the strip along the bund. The low lying areas which are subject to water logging should be converted into paddy fields. While in non paddy areas drainage facility should be followed either sub soil or surface drainage.

• Irrigation Schedule

Irrigation should be schedule when the soil temperature is moderate. In hotter season it is better to irrigate the field during the late afternoon or at night so that both soil and plant get sufficient time to absorb water before dry and desiccating weather prevails the next day. During the very cold season water should be applying during the morning hour, when the soil starts warning up. Frequent irrigation increases application loss and cost but it helps to increase use efficiency of fertilizer and other inputs. However, how much water should be applied in each irrigation depends on the need of the crop for water, the availability of water for irrigation, the capacity of the root-zone soil to store water, the season of raising the crop, the cultural practices and the anticipated rainfall.

Thus water is use effectively and efficiently by preventing its losses through run-off, downward movement of drainage, evaporation from soil surface and its losses through application methods and also preventing loss of excess water the cultural practices alongwith mechanical practices viz. land leveling, bunding, special shaping or belts, plots or fields should be followed. For effective use of irrigation water timely weeding and other cultural practices and irrigating the crop before soil moisture is depleted below 50% of its availability in the root-zone.