Everything you need to know about maize cultivation in India. Learn about:- 1. Introduction to Maize 2. Geographic Distribution of Maize 3. Climate 4. Soil 5. Field Preparation 6. Time of Sowing 7. Planting Density 8. Manure and Fertilizers 9. Nutrient Required 10. Water Management 11. Weed Management 12. Cropping Systems 13. Harvesting and Threshing 14. Yield and Storage 15. Varieties.
Contents:
- Introduction to Maize
- Geographic Distribution of Maize
- Climate Required for Maize Cultivation
- Soil Required for Maize Cultivation
- Field Preparation for Maize Cultivation
- Time of Sowing of Maize Crops
- Planting Density of Maize
- Manure and Fertilizers Required for Maize Cultivation
- Nutrient Required for Maize Cultivation
- Water Management for Maize Cultivation
- Weed Management for Maize Cultivation
- Cropping Systems of Maize
- Harvesting and Threshing of Maize Crop
- Yield and Storage Maize Crop
- Varieties of Maize
1. Introduction to Maize:
Maize is a crop par excellence for food, feed and industrial utilization. Maize grain has long been valued as an important source of energy for human and livestock diets. As a food, corn grain is a good source of carbohydrates (60% starch), lipids (5% oil) and proteins. However, the protein content is relatively low (7-8%). The maize protein is prolamines soluble in alcohol chiefly zein, which is deficient in the essential amino acids lysine and trytophan.
The starch in corn grain has historically been fermented by yeast to produce ethyl alcohol (ethanol; CH3CH2OH). Ethanol is an intoxicating liquid for people, but it has many industrial uses. Currently, corn based ethanol is used as a replacement for gasoline produced from fossil fuels.
One bushel (Bushel is a unit of volume for expressing crop yield, 1 bushel = 2150 cubic inches or 35000 cubic centimeters) of corn can produce at least 2.8 gallons (10.6 liters) of ethanol and about 18 pounds (8 kg) of grain by-product. Other industrial products of corn include biodegradable plastics, packing materials, glues, and lubricants.
2. Geographic Distribution of Maize:
Maize is the world’s third most important cereal crop after wheat and rice. It is grown everywhere in Americas, Asia and wet niches in Africa. It is cultivated globally over an area of about 147.26 million ha with a production of 724.6 million tonnes of grain. Considering its average yield of 49.20 q/ha, maize ranks first among cereal crops followed by rice, wheat and millets.
Maize cultivation in India is being practiced on 8.12 m ha area mainly as rainfed crop during kharif season and about 23% maize is grown under irrigated condition. Among the states, Rajasthan, Karnataka, Andhra Pradesh, Uttar Pradesh and Bihar are leading producers of maize.
Rabi maize cultivation is popular in Bihar, Andhra Pradesh, Tamil Nadu, Maharashtra, Karnataka and Uttar Pradesh. Summer maize is largely confined to states of Bihar, Karnataka and West Bengal. Comparing with the world productivity of 49.20 q/ha, the maize productivity in India is very low (23.35 q/ha) because of its cultivation under rainfed situation and high incidence of insect pests, diseases and weed problems.
The total sunlight available during rainy season is only 110-120 days forcing to grow short duration varieties which results low yield. In India about 55% of the maize produced are used for human consumption, 14% for livestock feed, 18% for poultry feed, 12% for starch and other food processing and 1% for seed.
3. Climate Required for Maize Cultivation:
Maize is a warm weather crop and grows right from sea level to over 3000 m altitudes. It requires adequate moisture and warmth from sowing to end of flowering. Being a thermophylic plant, it requires 1800-2600°C of total biologically active temperature (over 10°C) for its normal development.
Good germination of this crop is observed at soil temperatures of 20-22°C, while the optimum temperature for the growth of maize lies within 28-32°C. At extremely high temperatures coupled with low relative air humidity (about 30%) during flowering damage the foliage, desiccate the pollen and interfere with proper pollination, resulting in poor grain setting. It cannot withstand frost at any stage of its life cycle.
The crop can be successfully grown in areas receiving a well distributed annual rainfall of 50-100 cm. The crop also grows well in areas with annual rainfall of 250 to 400 cm (Assam and West Bengal hills), provided the fields are not flooded. It has been estimated that crop needs more than 50% of its total water requirement in about 30-35 days after tasseling. Inadequate soil-moisture at the grain filling stage results in poor yield of shrivelled grains.
Maize plants develop both in short-day and long-day conditions, but short day favours rapid growth. As maize is a C4 plant, it requires bright sunny days for an accelerated photosynthesis and rapid growth of the plants but this has to be coincided with the optimum water supply, otherwise the crop will start wilting due to moisture stress. Prolonged cloudy weather is harmful for the crop, however intermittent sunlight and cloud or rain is the ideal conditions for the growth and development of the crop.
4. Soil Required for Maize Cultivation:
Maize kernels need a soil that is warm, moist, well supplied with air, and fine enough to give good contact between seed and soil for rapid germination. Maize grows well on various types of loose soil having high water permeability, water holding capacity with good fertility. The soil should be medium textured with good water-holding capacity. It does not thrive well on heavy clays, especially low lands.
It is observed that a loam or silt loam surface soil and a brown silt clay loam having fairly permeable sub-soil are the ideal soil types. It can be grown successfully in soils with pH ranging from 6.5 to 7.5. The alluvial soils of Uttar Pradesh, Bihar and Punjab are suitable for raising good maize crop. The soils with sandy loam to silty loam texture are best for the crop.
5. Field Preparation for Maize Cultivation:
In order to eliminate weeds, facilitate sowing, provides aeration, better seed soil contact and to improve water retention capacity of the soil, one deep summer ploughing after rabi crop is necessary. It helps in an early sowing of the crop after giving one light ploughing by country plough followed by planking.
For heavy soils, 2-3 ploughing are needed. In areas of high rainfall during kharif, ridge and furrows are made in the whole field and seeds are sown on the sides of the ridges and furrows are meant for drainage. However, during rabi, spring and summer seasons planting in furrows is preferred over ridge planting in order to achieve higher water use efficiency and better yields.
6. Time of Sowing of Maize Crops:
Planting maize early is important to use the entire growing season and maximize grain yields. Temperature and moisture availability is the decisive factors in choosing the optimum time of its sowing. However, with the availability of thermo and photo-insensitive varieties, it is now possible to grow this crop round the year.
Usually 3 crops of maize, viz. kharif, rabi and spring are grown in the country. As a rainfed kharif crop, maize sowings are spread over the months of June and July corresponding with the onset of monsoons. In northern hilly regions, the crop is sown in May. As an irrigated kharif crop, it is sown a fortnight or a month before onset of monsoon to avoid water logging damage to seedlings due to heavy rainfall.
The experimental evidence indicates that 10-15 days sowing ahead of monsoon results in 15% higher yields of maize than obtained from the fields which are sown with or after onset of monsoon. In north India, this practice helps in taking an early rabi crop of toria or potato before wheat.
Rabi and spring maize is gaining popularity due to chances of getting higher yields. Besides, their sowing periods are flexible and thus can be accommodated well in any cropping system. However, rabi maize requires frost free climate with 12°C average temperature. Repeated frost severely damages the plants at all the stages. Rabi maize in Bihar and surrounding states of Indo-Gangetic plains is sown from September to November.
In north-western plains zone, sowing should be delayed beyond first fortnight of November, as it leads to poor crop performance due to cold climatic conditions. Cultivation of rabi maize is specifically beneficial in wheat growing tracts infested with weeds like wild Auena fatua (wild oats) and Phalaris minor.
The spring crop is sown during late January to end of February under irrigated conditions. Spring sowing is prevalent in the states of Bihar, Maharashtra and Uttar Pradesh. Baby corn can be planted all the year round, except December and January. Second week of September to first fortnight of February is the best for baby corn cultivation. For sweet corn, June-July (kharif) and September-October (rabi) are the optimum times of sowing.
Re-Seasons for High Maize Yields in Rabi:
Maize responds favourably to better crop management both during kharif and rabi, but the erratic rainfall pattern of the S-W monsoon restricts timely field operation in kharif. However, desired field operation can be planned and executed in the right time in rabi.
Moreover, crop during rabi do not suffer from waterlogging, leaching losses of fertilizers and damage from insect-pests and diseases. During rabi crop got 7-9 hours of sunshine compared to 3-5 hours during kharif besides, longer duration of crop growth which helps in accumulation of higher dry matter and maximum grain yields.
Moreover, maize plants in rabi tend to be more efficient in view of lower photo-respiration losses due to lower night temperature as well as larger effective photosynthetic leaf surface. Management of diseases and insect-pests, establishment of optimum plant stand owing to better soil and water management and better weed management are other factors responsible for higher yields during rabi than during kharif season.
Use certified seeds which are duly treated. Seed may be treated with Trichoderma uiridae and T. hazianum @ 4 g/Kg seed against soil borne diseases. Untreated seeds should be treated before sowing with bavistin @ 2.5 g/kg of seed.
The maize crop is sown in the country through following methods of sowing/planting.
Broadcasting:
This is a common method generally followed by the farmers. It is easy and quick method of sowing, but it is unscientific method as it requires more seed and poses problem during intercultural operations. Hence, this method should not be encouraged.
Drilling:
Commercially the crop is sown by drilling with seed drill. This method is quick and is suitable for light soils at all moisture levels and in other soils at optimum soil moisture. Under high rainfall area of heavy soil, the ridges are prepared and sowing is done on top. Under wet soil conditions, the tynes may get choked with soil resulting in blank rows. Excess water flows through the trenches and thus contact with seed or plant with water is avoided.
Sowing Behind the Plough:
Dropping the seeds in the furrows opened by plough followed by planking is also one of the most effective methods of sowing under low moisture condition. Moisture in furrows continues to be available for longer period. After germination, the seedlings are thinned out to maintain optimum plant stand.
This method is economical for water use as well as it also produces higher yield. Planting on the side of a ridge is adopted in high rainfall situations and on sloppy land. Planting in narrow furrow is followed in low rainfall areas. In normal conditions, planting on flat-beds and earthing-up operation is done after 40- 45 days of planting in areas where chances of heavy storms during rainy season.
Dibbling:
For maintaining optimum plant population and to avoid thinning, seeds are dibbled manually at required spacing. This method requires less seed rate, and is best for costly varieties/hybrids.
Hill Sowing:
Hill sowing is the other method adopted for sowing. In this method, the seeds are dropped with the help of corn planter placed at appropriate depth and pressed for dropping 3-4 seeds at a place (hill). It also requires less seed rate.
The speed of germination and emergence depends on planting depth and soil temperature. The depth of sowing depends entirely on the type of soil and length to which the mesocotyl (young seedling between the seed and the lower-most joint of the stalk) is capable of growing.
Under rainfed conditions, seed should be placed in moist zone viz. 7.0-8.0 cm in clay soil, 8-10 cm on silt and 10-12 cm on sandy soils. During rabi season when temperature is low, seed may be sown to a depth of 2-3 cm and when temperature is high, sowing depth of 6-7 cm should be maintained. Higher temperature is responsible for high evaporation rate and thereby less moisture content in the surface soil.
Thus, seed placed in that zone will not get sufficient moisture. Under optimum temperature conditions, a uniform depth of 5 cm is ideal for uniform germination. The optimum planting depth for sweet corns is 3-4 cm. One seedling/hill is optimum for all types of maize. However, 2 seedlings/hill are optimum for baby corn.
7. Planting Density of Maize:
In maize, each plant is important for realization of potential yields. Thus, one should ensure that the seed is viable and free from external infections. Seed rate and spacing are inter-related factors and both depend upon time of sowing, length of growing period, soil type, moisture availability, variety, size and weight of the seed. Maintaining optimum plant density in maize is highly desirable because unlike tillering plants like rice or wheat, maize cannot compensate for lost space.
During kharif, a plant population of 65,000-70,000/ha is recommended for grain production. The seed should be sown at a spacing of 75 cm x 18 cm or 60 cm x 22 cm. In rabi season, plants put up moderate growth owing to low temperature. Hence, it requires 30-40 % higher population than that of kharif season. Thus, it appears quite reasonable to increase the plant population to 80,000-100,000 plants/ha.
In this way the growing area per plant varies from 825 cm2 to as high as 1,500 cm2 and plant density varies from as low as 66,666 to as high as 1,00,000 plants/ha; depending upon the agro- climatic variations and cultivation practices. There may be a mortality of 10-15%, thus actually harvested densities tend to be much lower than those obtained after seeding. The inter row and intra row spacing for high grain yield is 60 cm x 20 cm.
Accordingly a seed rate should be adjusted to obtained desired plant stand. A seed rate of 15-20 kg/ha is required for kharif season crop, whereas high plant density is required for rabi maize, that can be maintained by using 25-30 kg seed/ha. Early maturing hybrids respond to higher plant density and vice- versa. Based on seed weight and the required plant population per ha, seed rate of 20-25 kg and 18-20 kg per ha may be sufficient for hybrids and composite varieties.
For baby corn, the optimum plant density varies from 1, 25,000 to 1, 43,000/ha with spacing pattern of 40 cm x 40 cm to 40 cm x 35 cm (with 2 plant/hill). In short statured hybrids still higher plant density (1, 75,000/ha) is maintained. Thus, baby corn would require 38-50 kg/ha of seed. The optimum population for sweet corn varies from 45,000-66,000/ ha with spacing of 70 cm x 30 cm or 100 cm x 15 cm. This would require a seed rate of 10-11 kg/ha.
8. Manure and Fertilizers
Required for Maize Cultivation:
Manure and fertilizers both plays an important role in maize production. The hybrids and composite varieties of maize exhibit their full yield potential only when supplied with adequate quantities of nutrients at proper time. The crop should be supplied with organic manure like FYM or compost @ 10-12 tonnes/ha before sowing the crop to ensures good tilth and improve the water-holding capacity.
Under irrigated conditions, for 10 quintal of grain production, maize crop consumes about 25 kg of N, 8 kg of P and 20 kg of K from the soil. As maize is an exhaustive crop and is generally grown in light soils, which may further aggravates the nutrient deficiency. The nutrients requirement of hybrids maize is higher because of its greater potentiality for grain production.
9. Nutrient Required for Maize Cultivation:
Nutrient requirement and their mode of application is, however, governed by many factors viz., soil type, variety, planting season, preceding crop, etc. For example, maize grown after potato needs relatively less fertilizers and so is the case of crop grown after any legumes. Similarly, irrigated crop needs higher doses of nutrients than rainfed ones. However, a balance application of 60-120 kg N, 40-60 kg P and 40 kg K/ha is recommended for various ecosystems.
i. Nitrogen:
The recommended dose of N varies with duration of the variety, its season of cultivation and stage of crop growth. The highest N requirement by the maize plant is found to be increased from seedling to knee-height stage and exhibited highest at the tasseling stage (about 4-5 kg N/ha/day) and thereafter its demand for N starts declining.
Therefore, adequate N supply should be ensured from sowing to the flowering (tasselling) stage. The N deficiency is characterized by stunted and spindly plant growth with yellowing of green foliage, especially the lower leaves. It has been noticed that the response of applied N is highest in the soils having low fertility status than the normal ones. Under an ideal fertility management it is observed that hybrids of maize yield 15-25 kg grain per kg of applied N.
Early maturing varieties require lesser quantity of nitrogen than full-season hybrids. For full-season maturity group, apply 100-120 kg N/ha; for medium maturity, 80-100 kg N/ha; for early maturity, 60-80 kg N/ha; and for extra early maturity, 40-60 kg N/ha is required. Rabi maize and baby corn require higher dose of N (180 kg/ha) than kharif crop and grain crop respectively owing to their higher population.
Results of various experiments conducted in different locations indicated that best results from applied N may be achieved when N is applied in three splits. In the first dose, 1/3rd of the total quantity of nitrogen should be applied in bands 7-10 cm away from seed rows and 5-7 cm below the seed layer.
The second dose of 1/3rd of the total nitrogen is to be given 5 weeks after sowing when plants attain 60 cm height (knee-high stage) and the remaining 1/3rd dose of the nitrogen should be top-dressed in the standing crop at the time of tassel emergence.
If water is a limiting factor, third dose should not be given. Among the methods of fertilizer application, placement below the seed and side dressing of N at second and third split application proved to be beneficial. On an average, the crop needs less N when grown during rabi season due to higher uptake and lower loss of nutrients from the field.
Likewise, during spring season when the crop is grown after potato, chickpea or field pea, it needs lower doses of N. About 100-125 kg N/ha is sufficient, but mode of application should be the same as in kharif crop.
Phosphorous is the next most important plant nutrient after N, which helps in growth and development of the plants and its deficiency causes purple colouration in leaves and tends to delay maturity with poor earheads. It exhibit its deficiency mainly at the seedling stage, but its requirement is high after flowering stage. It has a beneficial effect on root development and plant health. Maximum root development is completed until knee high stage.
Thus, the phosphorus should be applied initially at the early stage. Indian soils are generally rich in phosphorus contents, and thus, the crop does not respond well to the application of phosphorus. Therefore, response of applied phosphate is directly proportional to the fertility status of the soil as well as the previous history of phosphorus fertilization.
Under low or medium availability of soil phosphorus, application of 40-60 kg P2O5/ha is necessary for realization of higher yields. Due to its low solubility in water (less mobile), it should be applied in moist zone to be available quickly for early absorption by the plant. Basal placement of phosphorus in rows about 5-8 cm deep in the soil is highly desirable.
Potassium is considered as the third most essential fertilizer element but response to K fertilization is rare due to its sufficiency in Indian soils. It is essential for vigorous growth, translocation of water and photosynthates within the plant body. Potassium requirement is low during seedling stage, but its rate of uptake is highest during 20-25 days before tasseling stage.
Its deficiency is characterized by shortening of internodes, yellowing of leaves and firing at the margins of the lower leaves. To balance the nutrient status of the soil for better uptake of total essential nutrients, placement of 30-40 kg/ha of K2O, a little away from the seed is generally found to be quite adequate. In intensive cropping systems and low temperature regions of Himachal Pradesh and Jammu & Kashmir, K fertilization @ 30-40 kg K2O/ha is necessary.
In sandy soils and freshly levelled field the crop exhibits Zn deficiency. It is also noticed in the soils of north Indian states. Deficient plants show a broad band of bleached tissues on each side of the midrib, beginning from the base of the leaves. In severe cases, the apical leaves become white, a symptom called ‘white bud of maize’.
Therefore, it is advisable to apply 20-25 kg/ha zinc sulphate along with basal application of fertilizers. The deficiency of zinc in plants at later stages of growth, however, may be corrected by foliar application of zinc sulphate (ZnSO4) dissolved in water with half the quantity of lime (0.5% ZnSO4 + 0.25% hydrated lime).
Fertilizer Spray Application:
One or two sprays of 2% urea (spray grade with low biureat content) and application of micronutrient mixture when the crop is 3-5 weeks old crop would restore crop vigour which may have got setback due to delayed weeding and inadequate drainage. Higher concentration of urea should not be used as it may harm the crop.
General fertilizer recommendation for M. P. and C.G:
1. Long duration varieties irrigated condition – 150 kg N, 75 kg P2O5, 40 kg K2O and 10 kg ZnSO4 per hectare. N should be given in three splits viz., 1/3rd at sowing, 1/3rd at knee high stage and 1/3rd at flowering stage.
2. Long duration varieties under rainfed condition – 100 kg N, 50 kg P2O5, 25 kg K2O per hectare. N should be given in two splits viz., 1/2 at sowing and remaining 1/2 at knee high stage.
3. Medium duration varieties – 90 kg N, 40 kg P2O5 40 kg K2O per hectare. N should be given in three splits viz., 1/3rd at sowing, 1/3rd at knee high stage and 1/3rd at flowering stage.
4. Early duration varieties- 60 kg N, 30 kg P2O5, 20 kg K2O per hectare. N should be given in three splits viz., 1/3rd at sowing, 1/3rd at knee high stage and 1/3rd at flowering stage.
10. Water Management
for Maize Cultivation:
Maize responds well to irrigation though it is regarded to be sufficiently resistant to drought. However, the crop is highly sensitive to excess moisture and moisture stress at certain growth stages. During its vegetation the maize plant consumes tremendous quantities of water which it utilizes very rationally to from its organic mass. Its transpiration coefficient is 280-350, i.e., lower than in the wheat and barley.
Due to its well-developed root system spreading out to large soil areas, and to its long vegetation period, maize produces a large organic mass even in dry conditions. During grand growth period an adult maize plant transpire about 2-4 kg water daily. Hence, with a plant stand of 40-60 thousand plants per hectare, these plants use 80-240 tons of water daily.
To produce 100 kg of grain, on an average maize consumes about 60-100 tons of water, or 3000-4500 tons during its vegetation period. Maize as rabi and zaid season crop is grown under irrigated conditions only. However, protective irrigations are necessary under periods of moisture stress, during kharif season.
In kharif, 2-3 irrigations are required after sowing, whereas, spring crop requires 8-10 irrigations. Kharif maize sown before monsoon should be given a pre-sowing irrigation besides irrigation at 6-leaf stage. The other irrigations may be adjusted as per rainfall distribution. It must be ensured that the crop should not suffer from moisture stress at flowering and grain filling stages.
A good crop of maize (110-120 days duration) requires about 500-750 mm of water during its life cycle depending upon soil and climate. A vigorously growing maize plant needs about 2-3 litres of water/day during peak growing period or on an average its consumptive use of water varies from 2.5 to 4.3 mm/day. Adequate soil moisture content throughout the crop growth period resulted in maximum grain yield.
The optimum availability of moisture may be maintained by irrigating the crop at critical stages. The 6 critical growth phases for irrigation are seedling stage (6-leaf stage), knee high stage, tasseling, 50% silking and dough stages. Moisture stress at early growth stages results in delayed tasseling, silking and milking, consequently yield is reduced. Most critical stage for irrigation is flowering period (15-20 days) including tasseling, silking and pollination.
Highest decrease in grain yield is caused by moisture stress during these stages, mainly due to reduction in grain number per cob. Moisture deficit during these periods may cause the tassel and upper leaves to dry. The tassel may fail to shed viable pollen and fertilization will be only partial. Water shortage even for 2 days during tasselling to silking stage may reduce maize yields by about 20 percent. Success of the rabi crop of maize rests in proper water management.
Irrigated crop of maize besides pre-sowing irrigation should be irrigated at all critical stages. Frequency of irrigation shall, however, depend upon the moisture holding capacity of the soil, prevailing temperature and rainfall.
Maintaining an optimum moisture regime from knee-high to silking stage with 4 irrigations is highly conducive to crop growth as compared to other schedules of irrigation. If only 3 irrigations are available, then it should be timed at knee-high, flowering and silking stages. At times of cold or frost, irrigation is provided to minimize the damage to crop.
In baby corn, 15-20 days after sowing, knee high stage and pre-flowering are the critical stages of irrigation. Stress at any of these stages may result in barrenness and reduced size of baby corn. In sweet corn, tasseling and silking stages are critical for irrigation. The moisture stress at tasseling stage reduces seed set, and in extreme cases barren ears are also formed.
Under moisture stressed condition to achieve higher water use efficiency, crop should be sown in furrows instead of ridges. In low rainfall areas rain water can be retained in furrows near the root zone for a longer period of time. This may increase the yield of maize to the tune of 10 % than that obtained under ridge method of sowing.
Maize is highly sensitive to excess water (waterlogging) and hence efficient drainage is equally important as irrigation. It has been observed that water logging during flowering and grain development period may result in a yield reduction to the extent of 50% or sometimes cause complete crop failure, depending upon severity of water logging. To avoid water logging, sowing on ridges is desirable especially during monsoon periods.
11. Weed Management
for Maize Cultivation:
Maize crop is sensitive to weed competition during early growth phase due to slow growth in the first 3-4 weeks. Weeds emerge with the germination of maize seeds and grow along with plants till the early growth period. This causes a severe crop weed competition to maize plants.
The crop is found to be infested with both grassy and broad-leaved weeds. The most common grassy weeds of maize include Cyperus rotundus (Motha), Cynodon dactylon (Doob grass), Elensine aegyptiacum (Madhana), Digitaria sanguinalis (Takri ghas), Elusine indica (kodo), Echinochloa colonum. Echinochloa crusgulli (Sawan) Eragrostris tenella (Love grass), Sorghum halepense (Banchari), etc.
Prominent broad-leaved weeds are Cleome viscose (Hulhul), Commelina bengalensis (Kankoua), Celotia argentia (Chilibmil), Phyllanthus niruri (Hazardana), Portulaca oleracea (Naunia) Solatium nigrum (Makoi), Trianthema portulacastrum (Chupti), etc. They create acute problem in other rainy season crop also. If weeds are allow to grow in maize field they roughly remove equal or sometimes more amount of nutrients and moisture.
The maximum loss in yield due to weed competition is estimated to occur during the first 3-6 weeks after sowing (before the crop canopy has developed thick enough to smother the weeds) than later stages, because of lower competition offered by initial slow growth rate of maize plants and comparatively faster growth of weeds.
Therefore, first mechanical weeding is timed around this period. Weeds can be controlled either mechanically or chemically. Two hand hoeings 15 and 30 days after sowing keeps the weeds under check.
Mechanical hoeings should not be done after knee-high stage, as it may lead to foliage damage. Alternatively application of atrazine (Atrataf 50 WP) as pre emergence at 1.0 kg/ha in 500-600 litres of water provides weed free environment to maize over long period of time. Atrazine at the same rate can also be sprayed as early post-emergence i.e. within 10-15 DAS. Pre-emergence application (within 2 days after sowing) of alachlor (Lasso 50 EC) @ 2.5 kg/ha has been found effective in controlling annual grasses.
Some weeds like Brachiaria reptans (Bans patta), Commelina benghalensis (Kankaua) are less controlled by atrazine particularly when it is used continuously. Under such circumstances, these weeds can be controlled effectively with tank mix application of atrazine 0.75 kg/ha with pendimethalin 0.75 kg/ha or with trifluralin 1.12 kg/ha as pre-emergence after dissolving in 500-600 litres of water. The weeds from inter row area can be controlled with some contact herbicide like gramoxone or with intercultural operations.
12. Cropping Systems of Maize:
Crops like soybean, blackgram, greengram, and cowpea are raised mixed with maize. These legume crops are grown in space between 2 rows of maize. In Bihar mixed cropping of groundnut with maize is quite profitable.
In certain areas maize is intercropped with pigeonpea. In Rabi maize, intercropping of pea, rajmash, lentil, potato, onion, methi etc. is done in different parts of the country. In irrigated areas of north India, barley, wheat, toria, potato, blackgram, berseem, sugarcane, lucerne, oats are raised after maize.
Some of the most important crop rotations are given below:
1. Maize-wheat/gram/pea,
2. Maize-potato-onion/wheat/tobacco,
3. Maize-lucerne-maize-potato-sugarcane
4. Maize-wheat-muingbean/blackgram
5. Maize-potato-maize,
6. Maize-oat-napier grass
7. Maize-wheat-sorghum-sugarcane
8. Maize-wheat-cowpea
9. Maize-berseem/oat
10. Maize-toria-wheat,
11. Maize-wheat-cotton-berseem,
12. Maize-senji-sugarcane-cotton,
13. Maize-wheat-sugarcane Crops suitable for intercropping.
13. Harvesting and Threshing
of Maize Crop:
Maize crop grown for grain is harvested when sheaths turn brownish and grains become hard. At physiological maturity moisture content of grain may varies from 25-30 percent. There is no need to wait for stalks and leaves to dry, because they remain green in most of the hybrids and composites.
The cobs are plucked off the standing plants. Later on plants are cut with sickles. The husk is removed from harvested cobs/ears, then spread on the floor in open sun and dried for 6-7 days. Thereafter grains are removed either by beating the cobs by stick or with the help of maize sheller.
14. Yield and Storage
Maize Crop:
Well managed crop gives 5-6 tonnes grain/ha in case of hybrids and 4.5-5 tonnes in case of composites under irrigated conditions. In case of rainfed crop, yield levels are about 2.0-2.5 tonnes/ha for hybrids and 1.5-2.0 tonnes/ha for composites. Maize grain should have 15 % moisture for storage upto 6 months and for longer storage, grain should be dried to a moisture level of 13 percent.
Due to the immense genetic variability expressed in maize, genes that confer distinctive characteristics have been identified for special markets and uses. Speciality com includes pop com, sweet com, baby corn, high oil, waxy and amylo maize and quality protein maize.
Sweet Corn:
It is one of the most popular vegetables in the Western and advanced countries of the world. It is grown primarily as a food and is harvested with about 70% moisture before hardening and drying of the grain starts. It is a good source of energy. It is mainly grown in USA and Canada. About 40% of such corn is frozen and rest is canned while processing.
Among vegetables used for fresh consumption sweet-corn ranks sixth in the USA. This corn is differentiated from other types by the presence of specific gene(s) that affect starch synthesis in the endosperm. Sweet corn composites Madhuri and Priya have been released for commercial cultivation across the country. The sweet-com is popular in the country as an ingredient of soups and for other table purposes.
Sweet corn is consumed at green stage after roasting. The dry seeds are shrivelled and irregular in shape.
Variety – Madhuri, Priya, Sweet pearl (hyb)
Duration – 65-70 days
Seed rate – 5.0 kg/ha
Spacing – 60 cm x 25 cm
Fertilizer – 80-40-40 kg N-P2O5 -K2O/ha
(Nitrogen to be applied in 3 splits as in maize)
Harvesting – At green cob stage
Yield – 1.5 t/ha
Pop Corn:
It is one of the most common snack food in many parts of the world, particularly in the big cities and is preferred because of its light, porous and crunchy texture. It is consumed fresh, as it has to be protected against moisture absorption from air. When heated to about 170°C temperature, the grains swell and burst, turning inside out.
At this temperature moisture held in the starch of the kernel tissue turns to steam and the pressure causes the endosperm to explode. The pop-corn ground into flour to grits can be used for preparing many traditional dishes. The pop-corn varieties released for commercial cultivation are Amber, VL Amber and Pearl popcorn.
Baby-Corn:
Baby-corn is a delicious and nutritive product fetching a very high price in the national and international market. The unfertilized young cobs of maize is harvested within 1-4 days of silk emergence, depending upon the development condition of the plant and size of the shoot, commonly used by food industry, in terms of baby-com. It is becoming popular in the developed as well as developing countries, as it is used in the preparation of various dishes.
Baby-corn is a delicacy in star hotels, served as raw/soups or cooked in many recipes. It is used for culinary purposes for making curry, pakoda and other food items. There is a good scope for growing baby corn to improve the economic status of poor maize growers. The economic potential of canning baby corn as a small scale food-processing venture needs to be explored.
In India its cultivation is only now picking up in a serious way in Meghalaya, Western UP, Haryana, Maharashtra, Karnataka and Andhra Pradesh. Now leading private sector companies in India like Advanta India Limited are offering hybrid baby corn seeds. At the moment opportunities for baby corn appear to exist mostly in export market. Few companies -like Namdari Seeds – are selling fresh baby corn at retail food outlets like Food World in Bangalore.
Baby corn production generally requires the cultivation practices recommended for normal corn production, except that the crop cycle or duration is only about 60 days as compared to the 110-120 days duration of the grain crop. Here is a quick look at some of the main agronomic requirements.
Soil:
Well drained, sandy loam to silty loam soils are best suited for baby corn cultivation. It can also be grown in well drained black soils.
Land Preparation:
The land must be deep ploughed once and the soil must be worked up with a harrow and then a cultivator to bring it to a fine filth and to minimise weed problem. Apply the well decomposed FYM and mix it well with soil by running a cultivator. Land must then be laid out into ridges 40-45 cm apart.
Sowing Time:
June-July, October-November and January-February sowings are recommended.
Seeds Rate:
35 – 40 Kg/ha (Hybrid/Composite/Good varieties). Seeds must be sown as 15-17.5 cm distance on one side of the ridge. Plant 2 seeds per hill and then there would be approximately 90,000 – 100,000 established plants per acre.
Fertiliser Application:
Farm Yard Manure @ 10 t/ha should be applied 30 days before sowing. A basal dose of 50 Kg/ha of Nitrogen, 75 Kg/ha of P2O5 and 60 Kg/ha of K2O should be applied.
Subsequently, 40 Kg/ha of nitrogen should be applied between 25 and 30 days and another 30 Kg/ha of nitrogen should be applied 45 days of sowing. The above fertiliser recommendation would vary depending on rainfall and local agro-climatic conditions.
Weed Control:
Spraying of atrazine at the rate of 2.5 kg (for sandy loam) to 3 kg (for black soil) dissolved in 750 litres of water on the soil on the day of sowing or the next day after irrigation.
Plant Protection:
Baby Corn is a 60 days crops and thus chances of being infested by pests and diseases is less but any attack by pest and disease would reduce the plant’s ability to grow and hence reduce yield. Thus preventive measures are always recommended.
De-Tasseling:
De-tasseling is an essential operation in the cultivation of baby corn. It is done by removing the tassel of the plant as soon as it emerges from the flag leaf and before it starts shedding pollen grains. If this is not done, Baby Corn can get pollinated and the quality gets affected.
Harvesting:
Harvest immediately after the silk is visible. The optimum size requirement for the market and canning industry is 4.5 to 10 cm long and 7-17 mm in diameter of young de-husked baby cob. Besides, the young cob should be light yellow in colour with regular row arrangement.
Yield:
The production potential of baby-corn is good (1-1.5 t/ha) and economic returns are also high.
Maize as Green-Ear:
Maize ear for consumption as roasted green-ears is highly popular in metropolitan cities and also in rural areas. The farmers get remunerative prices for the ears (cobs) and also the green plants serves as good quality fodder for cattle.
Cultivation of maize for green-ears can be done throughout the year under irrigated conditions. The ears with tight husks are preferred, as they have longer shelf life, besides protection from bird damage. Some of the released com varieties are suitable for green ear cultivation.
Quality Protein Maize (QPM):
Maize grain is deficient in essential amino acids, lycine and tryptophane. Quality protein maize (QPM) opens new vistas and exciting prospects to improve the nutritional quality of maize. Due to high biological value, the QPM can fit well in infant foods and other preparations aimed at energy food items.
Three high lycine, nutritionally superior opaque-2 composites viz. Shakti, Rattan and Protina, released earlier could not become popular due to low grain yield, soft and chalky endosperm and grain with high susceptibility to ear rot and stored grain pests, to overcome this problem, one opaque composite Shakti 1 was developed which has hard endosperm and nutritionally superior. Lateron, Shaktiman 1, Shaktiman 2 and HQPM 1 have been also released for commercial cultivation.
High-Oil Maize:
In industry maize endosperm is used for starch extraction and in the process germ is separated, which is used for extraction of oil and remaining portion is used as baby food or cattle feed as it contains about 30% protein. Normally 3-4% oil recovery is possible from maize.
There are several processes that convert either grain or maize stover into food and chemical products. The processes are wet milling and dry milling.
Wet Milling:
In wet milling processes maize grain is separated into its four major constituents i.e., oil, starch, fibre and protein which are all sold at higher prices than the grain. It produces abundant starch (65 %) kernel weight) that is easily recovered and that can be processed to high purity.
Maximum amount of starch is used in the manufacturing of hydrolyzed products, mainly sweeteners, and the rest is used as industrial starch. The wet milling industry also produces various modified maize starches for paper lamination, textile wrap, coatings and laundry finishing. Corn oil is produced from corn germ and it contains 60% linoleic acid.
Dry Milling:
Dry milling involves three processes- (i) tempering degerming process, (ii) stone-ground or non-degerming process, and (iii) alkaline cooked process. In India maize is milled largely by dry milling process (stone ground) for producing flour and feed to the livestock and poultry industry. In USA, the dry milling industry consumes only about 2 % of maize production and use of dry milled maize products are primarily for animal feed, brewing, breakfast cereals and other food and industrial products.
15. Varieties of Maize:
The maize varieties grown in India comprised the improved selection, hybrids, composites and synthetics. Indigenous maize cultivars comprise of various types of selection.
Hybrids:
Hybrids are the first generation (F1) from crosses between two pure lines. Hybrids exploit the heterosis vigour. It could be single gene or multiple gene hybrids or single cross or double cross hybrids such as hybrid Sartaj which is a double cross hybrid. Producing hybrid seed is a costly affair and therefore, hybrid seed is costlier than the seeds of common varieties.
Composites:
A composite variety is produced by mixing the seed of several phenotypically outstanding lines and encouraging open pollination to produce crosses in all combinations among themselves.
Synthetic:
A synthetic is produced by crossing a number of lines that combine well with each other.
It is an established fact that the synthetic hybrid varieties lose their characters very fast when grown commercially because of cross pollination and their yield is found to be reduced drastically, if grown repeatedly with the same seed while composite varieties are more stable and show wide range of adaptation than the hybrids because of their broad genetic base.
Thus, for getting higher yield it is necessary to use new hybrid seed every year. However, seed of composites may be used year after year upto 3-4 years without significant reduction in their yields.
Varietal Improvement:
The maize improvement programme got a boost with the establishment of All India Coordinated Maize Improvement programme (AICMIP) in 1957. A large number of double cross hybrids and composites were developed and released from then onwards.
However, since 1980’s, single cross hybrids development is given more emphasis. Trishulata (three way hybrid) and Paras (first single cross hybrid) were thus released in 1991 and 1995, respectively. This was followed by release of three early maturing single crosses Pusa Early Hybrid Makka-1, Pusa Early Hybrid-2 and Prakash.
The AICMIP was renamed as Directorate of Maize Research since 1994. With increasing emphasis on rabi maize cultivation, cold tolerant cultivars (Pratap and Pratap-1) were evolved in Punjab in 1983 and the same were adopted in Haryana too.
Speciality corn (popcorn, sweet corn, baby corn), high oil, waxy and amylo maize and quality protein maize [QPM (with 02 gene and hard endosperm)] development has been emphasized since 1970’s. Since, maize is deficient in essential amino acids, lycine and tryptophan. To overcome this deficiency quality protein maize (QPM) cultivars with sufficiently higher quantity of lysine and triptophan using opaque 2 genes have been released for cultivation in India.
The QPM hybrids released are Shaktiman 1 (2001) and Shaktiman 2 (2002), HQPM1 and composite Shakti 1. Other speciality corn cultivar includes Amber popcorn (1981), VL Amber popcorn (1981) and Pearl popcorn (1995) were developed. The sweet corn composites developed include Madhuri (1990) and Priya (2002). Though no exclusive baby corn types were evolved, early maturing hybrids developed (Prakash, Vivek 4, Vivek 5, Pusa 1 and Pusa 2) have been found suitable for this purpose.