Wheat and Rice are the two major staple food crops in Pakistan cultivated on the largest acreages. Wheat 1st staple food crop covers 8.7mha of Pakistan with 25.49 million tonnes annual production.
According to Economic Survey (2017-18) of Pakistan wheat share in GDP is 1.7% while 9.1% value added in Agriculture by wheat. 43 countries of the world are producing wheat and Pakistan ranked at 8th position in wheat production in terms of yield/ha.
Worldwide wheat accounts for 30% of all cereal food crops followed by rice 27% and maize 25%. Rice as 2nd food crop is cultivated on 2899-thousand-hectare area with 7442 thousand tonnes production in Pakistan. Rice share in GDP is 1.1% and provides 42.3% labor force. 114 countries around the world cultivated rice and Pakistan ranked at 9th position in terms of Rice yield/ha.
Rice-Wheat Cropping System in Asia:
In Asia rice-wheat cropping system has been practiced for more than 1000 years by farmer community. Since currently it has expanded and estimated on an area of 23.5mha. In South Asia, the rice-wheat cropping system covers 13.5mha: India (10.0), Pakistan (2.2), Bangladesh (0.8) and Nepal (0.5) million hectares. It represents in these countries’ wheat covers 42% and rice 32% total area.
In the Indo-Gangetic Plains (IGP), which extends to these four (India, Pakistan, Bangladesh, Nepal) countries, generally rice is cultivated from May/June to October/November (wet summer) and wheat from November/December to Feb/March (dry winter). Most of the area in Indo-Gangetic Plains is irrigated; however, it also receives 425-800 mm annual rainfall.
- Rice-Wheat Cropping System in Punjab:
A cropping system is an opportunity for the farmers to help them in decision making in an ever-changing environmental condition in agriculture to remain sustainable. In the rice-wheat tract of the Punjab, wheat and rice cropping system account for over 80% of the total cropped area. In Pakistan, the rice-wheat cropping system is the major one which account for total 2.2mha of area.
In Pakistan, the rice-wheat cropping areas are mainly located in central Punjab (main districts include Gujranwala, Sheikhupura, Narrowal, Hafizabad, Lahore, Okara, Jhang, Mandi Bahaudin) followed by Sindh. In these areas, wheat is usually grown by broadcast method and rice by transplanting 25-35 days old nursery seedlings in well-Puddled and flooded field conditions.
This major one cropping system in South Asia and parts of East Asia requires particular management practices as both crops require contrast growing conditions. Rice grows well on puddle compacted soil with standing water conditions as compare to wheat crop which performs best on well-drained soils.
There could be two possible ways to reduce cost of production either we decrease our input cost while making efficient use of available resources and decreasing input losses or we improve our average economic yield through adopting innovation and adding more inputs in an intelligent way.
Issues of Rice-Wheat Cropping System
- Late sowing of wheat:
Delay in the sowing of wheat after rice directly or indirectly decrease input use efficiency of the system. Late sowing results in a smaller number of growing degree days, less plant population and less tiller per hectare etc. Sowing of wheat after puddled rice crop cannot meet optimum sowing time recommendations because your rice crop is still in the field even at the end of November.
There are so many reasons for the late harvesting, including excessive tillage, too wet or too dry soil moisture conditions, lack of mechanical power for plowing, and the biasness in priority farmers turn on threshing and handling the rice before preparing sed bed for wheat. Major cause of late wheat planting is the long turnaround time between rice harvest and wheat planting.
- Structural Clash:
Structural clashes are always found between crops similarly as in rice and wheat crop, because both crops require different field conditions for growing as in case of rice, it requires hard pan below rootzone therefore frequent puddling practice is performed while for better growth of wheat well drained soil is required and hard pan can inhibit root growth for wheat.
To break hard pan created through rice cultivation and for making soil well drained, deep tillage is performed before sowing of wheat. It consumes more time and fuel which increases production cost of the system.
- Fertility Issue:
Rice and Wheat both are exhaustive crops that absorbed bulk of nutrients from soil and give nothing in return to the soil which is one of the main reason in the decline of soil fertility of rice wheat cropping system.It results in the decline of yield per acre year by year.
To alleviate this issue, efficient management of soil fertility must be ensured by minimizing the over mining of Primary nutrients, balanced fertilizer application in sufficient amount on the basis of soil test value or real time/site specific nutrient management.
Increasing Pest Population:
Pest population is increasing in soil bank as both are cereal crops with C3 cycle. Most of the weeds and pest are becoming adopted to the rice-wheat Cropping System.
After some years it makes difficult to control weeds and pest with the same formulation because they got resistance to most of applied chemicals in previous years therefore it is necessary to use alternative chemicals and pest control methods each year. Cost of managing pests will increase the cost production.
- Labor Issue:
Availability of labor for transplanting is also a problem due to increased industrialization in the recent years. Labor wages are also too high to about 6000 per acres in some areas of the country which increase cost of production.
Usually inexperienced labor is hired for the work, it ultimately results in poor plant population and injured nursery plants during uprooting and at transplanting time.
- Residue management:
Management of previous crop residues after harvesting is also a laborious work for the farming community. Most of the farmers used to burn their crop residues, which is one of the causes of global warming.
Although it is right of soil that biomass of crops should get incorporated into it except economic components which is not performed due to high cropping intensity now-a-days. Also, one of the main reasons behind continuous decline in soil fertility.
Modern concepts in Rice-Wheat Cropping System
- Direct Seeded Rice (DSR):
Rice is seeded at 9 inches spacing with the help of drill. Seeds are directly sown on beds in rows. Moisture stress is avoided at tillering, panicle initiation and grain filling stages of growth.Weed control is done manually and with herbicides. Puddling is skipped which saves water up to 30 percent. Less labor is required because nursery transplanting is not practiced. Its cost of production is less than transplanted rice.
- Bed Sowing:
Crop is sown on raised leveled surface mostly in lines. Bed size and furrow depth varies from crop to crop. Bed planter is used for making beds and sowing practices. Application of irrigation in furrows saves water up to 45%. Less seed rate (10%) than conventional sowing and more production up to 20% is achieved. Weed control is also feasible.
- Permanent Beds:
Beds are sometimes converted into permanent beds. Limited tillage practices are only for cleaning and reshaping of furrows. Residues of previous crop are left on surface acts as mulch and prevents erosion. Soil organic matter is also increased with the passage of time. Less irrigation water (25%) less operational cost (25%) and (8%) higher yields is achieved.
- Zero Tillage Sowing:
In zero tillage system crops are planted with minimum soil disturbance. Seeds are placed with the help of drills of inverted T or double disc openers. It improves soil heath, timely sowing of crops is possible, production cost is also minimized due to least number of tillage operations. It is best suited for partially reclaimed soils. Turbo seeder is a best option as compared to zone disc tiller in Zero tillage system.
It is a practice of turning succulent green plant tissue into the soil.The purpose of green manuring is to add organic matter in the form of undecomposed biomass. Green manuring with Jantar (Sesbania) can overcome the problem of continuous decline in fertility and an organic way of managing soil fertility. Lucerne can be used as an alternative to sesbania as it gives additional benefit of one cutting for animal feed as well as improving fertility of soil.
Authors: Muhammad Hamza Latif, Zarina Batool and Zeeshan Arif
Department of Agronomy, University of Agriculture, Faisalabad.