Groundnut is an important cash crop in barani areas (potohar Region) of upper Punjab and parts of KPK. In Sindh, it is grown under irrigated conditions. About 84 % of the total groundnut area lies in Punjab, 13% in KPK and 3 % in Sindh. During 1998-99, the total area under groundnut was 97,500 hectares with the production of 104,000 tons and average yield of 1067kg/ha.
The sub-soil as well as surface soil play an important role in obtaining higher yield and the quality of groundnut. A well-drained, coarse textured and sandy loam soil is suitable for groundnut production. Pods produced on these soils will be clean and bright as desirable market trait. Soil which contains an appreciable amount of clay may result in crust formation and the pegs may not be able to penetrate into the soil for fruiting, moreover, it is very difficult to harvest groundnut grown on such type of soils. Sandy loam soils are generally low in fertility, therefore, balanced doses of fertilizer and their timely application is very important.
The primary tillage operations should be performed at least one month before planting. For March-April planting, deep tillage with mouldboard plough up to the depth of 25-30 cm is recommended in early to mid-February. This operation open the soil and preserves soil moisture by recharging from subsequent rains. Mouldboard plough should be followed by a disc/harrow to level and pack the soil. A well prepared seedbed results in good germination and healthy seedlings, thus the proper plant stand is maintained.
The soils in barani areas are generally deficient in several nutrients. This deficiency can be corrected by the addition of proper dose of organic fertilizers. Organic manure is important primarily as humus that are decomposed by soil organisms to provide them nutrient and energy. Farm yard manure is mainly used as organic manure. It should be applied about one month before sowing and incorporated properly in the soil.
Nitrogen, phosphorus and potassium are the three major nutrients required for this crop. An ideal rate is 20 kg N, 80 kg P2O5 and 60 kg K/ hectare. If soil is more sandy or intensively cropped, 100-kg K/ha is recommended. These rates may be obtained by using a mixture of Single Super Phosphate (SSP) and Urea or Ammonium Sulphate or with Di-Ammonium Phosphate (DAP). Micro nutrient deficiencies iron, zinc and boron are the most oftenly observed deficiencies. Appropriate use of these nutrients in the form of spray or soil application could alleviate the symptoms.
Gypsum plays an important role for higher production per unit area. Application of gypsum @ 400-500 Kg/ha just at beginning time of monsoon season (crop planted in March-April), when flowers produce viable pegs and at flowering time of the late planted crop gives good results. In more sandy soils higher rates of gypsum are required due to increased leaching.
Two types of groundnut vaieties, spreading (runner) and erect or bunchy types are widely grown in Pakistan. List of suitable promising varieties, their yield potential and maturity duration is given in the following Table.
Seed selected for planting should be bold, uniform well matured and disease free. Pods should be shelled a few days before planting and treated with proper fungicide. Early shelling may result in the deterioration and loss of viability and vigour. To get optimum plant densities, recommended seed rate for different types of groundnut is as follows:
Spreading and semi spreading types: 75 –80 kg / ha (167,000 plants)
Bunch and semi bunch types: 95-100 kg / ha (220,000 plants).
Groundnut is a highly efficient legume crop. It begins to supply its own nitrogen after 30-40 days from planting if the correct soil bacterial are present. It is essential to inoculate the seed immediately before planting with efficient rhizobium strain to obtain higher yield.
Groundnut can be grown successfully in the areas where 250-300 mm well distributed rain is received during the growing period of April to September. .Mostly groundnut in Pakistan is planted in fallow lands from early March to end April, in conserve soil moisture received during winter rain. It can also be planted in May and June after wheat harvest if adequate moisture is available. But the crop doses not mature properly and yield decreases considerably. The optimum planting time in Punjab (Pothwar area) is April. Under irrigated conditions, it is planted in early March and harvested in August. In Sindh, the best planting time reported is May. Short duration varieties maturing in 120-130 days can be planted at the onset of monsoon in late June or early July.
Groundnut is usually planted 4-6 inches deep on light soils and 2-4 inches on heavier soils. For cultural operation ( hoeing, spraying, weeding) and mechanical digging, it should be planted in straight lines. BARD precision planter has been developed and successfully demonstrated in farmers fields for planting different types of groundnut at various plant densities. Other planting methods for line planting include kerra and pora or dropping seeds through (naali) funnels behind tractor drawn cultivator or through funnels on desi plough.
Plant and Row Spacing
Based on previous research findings, the general recommendation for groundnut in Pakistan is to plant bunch, semi bunch varieties with 45 cm row spacing and 10 cm plant to plant spacing, which results in a plant density of 220,000 plants / ha. On sandy soils (in low rainfall zones) plant to plant spacing should be increased to 15cm resulting in a plant density of 1,48,000 plants/ha. Spreading and semi spreading type varieties should be planted with 60 cm between rows and 10 cm between plants, resulting in a plant density of 167,000 plants / ha, whereas, in sandy soils or medium to low rainfall zones, plant spacing within rows should be 15 cm to achieve a population of 111,000 plants/ha.
For planting groundnut under irrigated conditions, a rouni is needed for seedbed preparation. First irrigation three/four weeks of sowing second irrigation at flowering ,third irrigation at peg formation, fourth at pod development and fifth about one month before digging, should be applied if required.
Weeding with khurpa, kasola or rotary hoe and cultivator with small sweeps ( tractor drawn) in the direction of rows may be completed when it is required.These operations perations should be completed before peg formation so that the young pegs entering into the soil may not be demaged. The first weeding can be done about four to five weeks after planting and the second weeding before peg formation.
Herbicide can be an effective weed management tool for groundnut in Pakistan, if applied properly at proper time. Fusilade (Fluazifop P-Butyl) a selective (post-emergence herbicide) for grassy weeds and Johnson grass in groundnut growing areas has been successful @ 1-2 liter/ ha, but has not yet been registered in Pakistan.