By Hafiz Abdul Wajid Bhatti, M. Bilawal Junaid, Aqib Mahmood and Dr. Irfan Afzal
WITH AN increasing global population demands high crop production to meet the food requirements, timely sown and proper method of sowing ensures the food security, food safety and environmental protection simultaneously. Transplanting provides maximum stand establishment, early flowering, maximum biomass production and more grain yield as compared to direct seeding. It is a best method to get maximum crop plants under same conditions. Transplanting is the technique of moving a plant from one location to another. Most often this takes the form of starting a plant from seed in optimal conditions, such as in a greenhouse or protected nursery bed, avoiding germination problems by setting out seedlings instead of direct seeding.
Maize is a C4 plant specie with higher temperature optima than C3 plant specie. With an ability to grow on diverse climates, Maize (Zea mays L.) is high yielding and important cereal crop of the world. Out of 1.1 billion tons of coarse grains produced in the world during 2010 for food, feed and industrial purposes, maize accounts for 74 per cent of aggregate output (FAO, 2010). In countries like Pakistan where population pressure demands an increase in food supply, it has a key role in cereal food supply. It ranked third after wheat and rice with respect to area under cultivation. During the year 2011-12, maize was cultivated in Pakistan on an area of 1083,000 hactares and production was 4271,000 tons with 15.2 per cent increase in production over last year (Govt. of Pakistan, 2011). Being relatively short duration crop, maize is capable to utilize inputs more efficiently and has potential to produce large quantity of food grains per unit area. In Pakistan maize is extensively grown twice a year as spring and autumn crop. Maize has greater nutritional value containing about 72 per cent starch, 4.8 per cent oil, 10 per cent proteins, 8.5 per cent fiber, 3 per cent sugar and 1.7 per cent ash.
In Pakistan maize can be successfully cultivated twice a year in autumn as well as spring season. The temperature between 25 to 28 °C is optimum for germination of maize and optimum temperature for maize growth ranges from 30 to 35 °C. During spring plantation, a high day temperatures of 38°C at reproductive stage directly affect pollination and seed setting resulting in reduced grain yield.
Performance of spring planted maize can be improved by reducing the damaging effects of low temperature upon germination and emergence and of high temperature on pollination and grain filling by early plantation of maize nursery in green house under favorable climatic conditions. The 20-day-old transplants established more rapidly in the field than older and younger transplants, and the patterns of leaf production of these young transplants were similar to those of direct-seeded maize.
Recommendations
Nursery should be sown before mid of December and should be closed under polythene sheet for temperature regulation and to control evapotranspirational losses of water. Nursery of 200 meter square is enough for one acre field. Daily irrigate the nursery. Nursery should be wet, there should be no shortage of water nor the excess of the water. Transplanting of seedlings in the field should be when nursery age becomes of 20 days at 2nd leaf stage. Soil should be well drained for nursery transplanting and irrigate the field before 1 week of transplanting that helps in early weeds emergence that are easy to kill. Before transplanting there should be herbicide spray on beds where seedlings will goes transplant. Thinning should be done after 25 days of transplanting.
Benefits of transplanting
Transplanted maize requires lower and rates to achieve similar yield levels to those realized with direct seeded maize. Nitrogen rate could be reduced by as much as one third with no loss in marketable cobs. Its adoption by smallholder farmers could help them realize higher yields compared to direct seeding since they generally apply low fertilizer N rates to their crops. Thereafter, the rate of leaf emergence of direct-seeded crops was comparable with that of 20-day-old transplants, but older or younger nursery from 20 days gives small, thin and fewer leaves. Transplanting is a strategy that can be used to achieve optimum plant densities that results in optimum yield, in areas such as Kasur, Sahiwal and Okara districts where bird damage is a serious problem. Transplanting results are in earlier maturity, early flowering and higher yields than direct seeding. More rapid growth with transplanting would contribute to improved water use efficiency resulting from both shorter crop duration and higher yields. Transplants help to lower herbicide requirements since the rapid growth of the maize seedling transplants tends to be more competitive with weeds than the slow establishment phase of direct seeded. Less tillage practices are required for transplanting, that reduces soil erosion by minimizing tillage practices. Transplanted gives higher harvest indices than direct-seeded plants.
On the other hand, transplanting pro-vides optimal environmental conditions for seed germination and avoids planting seeds in disease-contaminated soil.
Growth and developmental patterns of transplanted maize can differ significantly from those of direct seeded crops. Transplants tend to produce fewer leaves, to flower earlier and thus to benefit from longer grain-filling periods in the field. As a result of their advanced maturity, they give higher harvest indices than direct-seeded plants. Year to year variation in climate seems to be of primary importance for yield advantages of transplants over direct-seeded maize. The advantage of maize transplanting is therefore likely to be greater in poorer growing seasons.
In near future the use of transplanting technique for early crop growth promotion will be the most acceptable and applicable option because of its numerous, time saving, input saving, early maturity, early flowering and higher yield advantages.
The writers are associated with the Department of Agronomy, University of Agriculture,
Faisalabad.