GROWING wheat in rain-fed (barani) conditions is being practiced in many countries which are getting more yield than in ours due to adoption of better management practices.

Wheat production in rain-fed region can be enhanced by adopting certain management practices that include infiltrating and conserving moisture into the soil, selecting suitable wheat cultivars, well-timed sowing by recommended method, judicious use of fertilisers, controlling pests and weeds and proper harvesting of the crop.

Cultivation of the crop in rain-fed areas involves preservation of moisture, the crucial growth factor for crops, from rainfall. The moisture collected from the monsoon rains during July and August is infiltrated into the soil and preserved for growing wheat crop. The surface run off of water from excess rainfall can be preserved for future use by wheat plants.

To achieve the objective, the soil is loosened by tillage up to a depth of more than 20cm using a chisel plough before the advent of rainy season to enhance water permeation capacity of the soil. Exercising soils with mould board plough in the barani areas should be avoided as it turns the land upside down bringing salts at the surface layer hampering wheat germination and growth.

When the rains stop, the land is planked tightly to withhold maximum moisture. The moisture magnitude retained in the soil depends upon the extent of precipitation, temperature, degree of management and soil properties like depth, texture and organic matter status. For instance, a rainfall of less that 20cm adds very little water to soil not satisfactory for completion of wheat growth while the areas receiving a rainfall more than 50cm can be successfully put under wheat crop. Rain-fed lands may be left unsown during the summer season to provide all moisture contents conserved in the soil for successful wheat production.

Other techniques can also be employed to reduce moisture depletion from soil before and during the growing period. One such technique is the mulching of soil surface to avoid evaporation losses. Mulches can be natural including straw, leaves, farm residues, compost etc. or artificial including plastic sheet, rock, gravel etc. Moreover, spray of 100mm solution of glycinebetaine during the vegetative stages enables wheat plants to withstand against water stress.

Variety selection is crucial in the case of rain-fed grown wheat. Drought resistant or tolerant wheat varieties can better survive deficient moisture conditions. Research institutes in the country have developed varieties that are well adapted to rain-fed conditions. These include GA-2002, Chakwal-97, Rawal-87, Kohistan-97, Inqlab-91, and Pasban-90.

Sowing time for wheat in rain-fed areas is of key importance. Early sowing during last week of October and first week of November allows seeds to imbibe more water for germination due to sufficient moisture in the seeding zone. Moreover, temperature of approximately 25æC during this period supports rapid germination for a vigorous crop stand.

Seed rate for rain-fed crop is variable depending upon the time of sowing. In case of late sowing, the seed rate is increased. For instance, the seed rate for sowing up to 15 November is 125kg per hectare (ha) while late sowing between 16 November and 15 December requires 150kg per ha. Germination percentage of the seed must be equal to or more than 90 per cent.

Seed is soaked in plain water for 10-12 hours so that it may suck moisture to support germination. Wheat grains produced in rain-fed areas are usually petite than normal due to limited moisture. Therefore, precaution must be taken while selecting seed. Seeds are graded to remove undersized and shriveled sized grains for proper and uniform germination.

It is suggested that fields in rain-fed areas be sown using a drill without any preparatory tillage. Eventually the zero tillage drills are deemed better for wheat cultivation in rain-fed areas. Although, tillage plays significant role in managing weeds, however, moisture conservation is more critical while weeds germinated before sowing can be controlled using a non-selective herbicide like gramaxone or round up at 3.0L per ha and 2.5L per ha respectively.

Optimum seeding depth is imperative for uniform germination in rain-fed areas. Normally the seed is place 5-7cm deep in soil while the one placed deeper than 8cm results in reduce emergence leading to poor crop stand while seeds placed in near surface are unable to acquire enough moisture for germination. Drill sowing places the seed at adjusted depth. A distance of 15-20cm between the rows results in higher yields than 25-30cm distance.

Fertilisers if managed properly contribute more or less 50 per cent to total production of a crop. Moreover fertilisers enhance the 1000-grain weight, protein contents, gluten quality and bread making quality of the wheat. All fertilisers in rain-fed sown wheat are drilled along with seed and placed 5-8cm below the seed to maximise its utilisation. Fertiliser rates must be decided on the basis soil analysis and the amount of rainfall. However the general recommendations suggested by the agriculture department are as follows:

Area Annual rainfall Nutrient

(mm) elements (kg ha-1)

N P K

Low rainfall 350 57 57 60

Medium rainfall 350-500 85 57 60

High rainfall More than 500 115 85 60

Foliar application of two to four per cent urea and KCL solution at 50, 70 and 85 days intervals after sowing is advantageous to improve dry matter accumulation and net assimilation rate in wheat. Moreover, spray of five per cent zinc sulphate 60 days after sowing activates certain enzymes, promotes plant growth and boosts flowering and seed setting.

Weeds rapidly drain the soil moisture, fertiliser and other growth substances so required to be controlled from the very beginning. Pre-emergence application of stomp 33EC (pendimethalin) at 2.5L per ha effectively control weeds in rain-fed sown wheat. On the other hand sanitary measures and other cultural practices help minimise weed flora.

Termites severely threaten the rain-fed cultivated wheat by attacking the plant roots usually in patches causing the yellowing of plants and death in some cases. Chlorpyrifos 30EC application before the last tilling of soil solves the termite problem effectively.

Diseases like rusts, smuts, ear cockle and foot rot etc. can gravely diminish wheat output in barani parts. Pre- sowing seed treatment with fungicides like vitavax, carbendazine, benlate (each at 2g per kg of wheat seed) depresses the disease infestation. Rouging to eradicate infected plants prevents further dispersal of diseases.

Wheat crop matures little earlier in rain-fed areas than the irrigated ones. Grain hardening, turning of leaves to light yellow and drying of straw are the signs of maturity. Moisture status of wheat grains at maturation is 18-22 per cent which is reduced by drying to less than 12 per cent for safe storage.


Courtesy: The DAWN