Semi-arid or sub-humid zones are characterized by low erratic rainfall of up to 700 mm per annum, periodic droughts and different associations of vegetative cover and soils. Inter-annual rainfall varies from 20-50%. Regarding livelihood systems, in general, agricultural harvests are likely to be irregular, although grazing is satisfactory.


Pakistan lies in the subtropical arid zone and most of the country is subjected to a semi-arid climate. Linked to water, and based on physiography, in 1980 Pakistan was divided into ten agro-ecological zones, these are: i) Indus delta; ii) southern irrigated plain; iii) sandy desert; iv) northern irrigated plains; v) Barani (rainfed) areas; vi) wet mountains; viii) western dry mountains; ix) dry western plateau; and x) Sulaiman Piedmont.


Regarding climate, June is the hottest month on the plains and July in the mountainous areas, with temperatures over 38 °C, while the mean monthly minimum is only 4 °C in December/January. The average annual precipitation is around 494 mm, but is unevenly distributed. About 65% of the rainfall in the monsoonal climate is received from July to September, while remaining 25% is received during December to February. The extreme variability in seasonal rainfall directly affects river flows, which vary considerably during the Rabi and the Kharif seasons. Around 92% of the countrys area is classified as semi-arid to arid, facing extreme shortage of precipitation.


It has been stated that agriculture practiced on the semi-arid/rain fed areas of Pakistan remains 17% of the total area under crop production. During the last decade the total land area under agricultural use in Pakistan remained the same, i.e: 77.09 Mha while total arable land area counts to be 21.18 Mha. The total irrigated agricultural area is 19.12 Mhaand total rain-fed agricultural area is 3.67 Mha. Rain fed areas are concerted in the Pothwar Plateau, northern mountains and north eastern plains of the country. This area forms the countrys largest contiguous block of dry land farming. In Pakistan, the terms rain fed and dry-land are used alternatively. Dry-lands are the areas receiving less than 500 mm annual rainfall. About 75 percent of the area in Pakistan receives less than 250 mm annual rainfall. With the population of 30 million people, land resources of the rain fed areas are categorized by fragmented land holdings. Drought, simple cropping program and fragility of soil make ecology of the semi-arid regions vulnerable to degradation of vegetation, water loss, soil erosion and desertification. Based on the limitations linked with these areas, agricultural activities contribute only about 10% of the total agricultural production.


Since the last few decades, a number of low-cost and more effective technologies, including plastic film mulching and rainwater harvesting strategies, have been extensively established and applied in semiarid agro-ecosystems of the world. One innovative water-saving technology, entitled as ridge-furrow with plastic film mulching (RFPFM) system, has been established to considerably enhance the precipitation use efficiency in rain-fed farming systems in arid and semiarid areas worldwide. In this technique alternate ridges and furrows are dug along the contours. Most probably, the mulched ridge is utilized for rainwater harvesting zone, and mulched or non-mulched furrow is treated as planting zone.


Mulching furrows with plastic film can inhibit soil evaporation, improve the soil moisture availability in the furrow, regulating the soil temperature, and promote crop growth, thereby significantly increasing the crop yield and the water use efficiency. Ridge and furrow mulching cultivation does not significantly change seasonal evapotranspiration, but it can regulate water availability during critical growth stages. In the long term, treatment with plastic-covered ridges and straw covered furrows (PS) will bring an increase in the income of farmers.


The major detriments of the ridge and furrow plastic film mulching (RFPFM) system is labor cost and planting area reduction, while key returns are soil and water conservation, improvement of soil moisture, topsoil temperature, soil nutrient availability, and prolonged growing seasons inducing an increase in the agricultural production. Further, the RFPFM system has been proved to be a valued technique for suppressing weeds, insect pests, and for improving cold tolerance. The merits of ridge and furrow plastic film mulching (RFPFM) practice are well evidenced in maize, wheat, alfalfa, potato, etc in different parts of the world. So, merits of this system are as much that its demerits can be neglected.


Common plastic film is a major mulching material which is incapable of bio-degradation in the field. Thus, bulks of residual plastic film have a devastating effect on soil structure, water and nutrient transport, crop growth, and animal health. In this manner, residual plastic film interrupts agricultural environment and diminishes crop production. Currently, there is no treatment available for solving this problem, and a dearth of research on the application of new biodegradable films.


Agricultural growth of the country has been improved from 0.2% of countrys gross growth rate during 2009-10 to 2.9% during 2014-15 but it is still far ahead from the actual target according to economic survey of the countrys gross growth rate 2014-15. It is because of neglecting rain-fed agriculture and focusing mainly on irrigated farming. Moreover, according to the last census, population of the country is advancing at a high speed with net annual addition of 3.4 million.


In fact for the last 50 years in Pakistan, major focus of research has been on irrigated farming and rain fed agriculture has almost been neglected with no significant work done on dry land system. Research works on water harvesting and moisture management in accordance to ridge and furrow plastic film mulching (RFPFM) in semiarid rain fed areas of Pakistan are inadequate. So, this is the time to focus on this novel system in such areas in order to meet the rising nutritional demands of increasing population and to attain the actual target of agricultural growth.

By Web Team

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