Rise in temperature: A big challenge for maize crop
Tahir Abbas, Asif Imran, Abdul shakoor, Muhammad Shahid and Nazar Manzoor
Pakistan is blessed with four seasons, but these seasons are changing due to global warming. The global warming is a big threatening issue for food security in the world. Temperature is rising day by day due to human activities such as urbanization, industrialization, deforestation, burning of fossil fuels and unchecked use of pesticide and fertilizers which increase the temperature due to volatilization process and greenhouse effect due to release of CO2, CH4, NO2 and CFCs. Chlorofloro carbon is release due to over use of air conditioners and refrigerators this deplete the ozone layer and ultra violet rays directly fall on earth and increase the temperature which is a threatening for the future crop production. Global warming which is a current issue worldwide which is considered to be a food security causing factor worldwide. According to the worldwide survey by World Bank Pakistan is at 12th position among the list of vulnerable to climate changing countries. So there is need to overcome this problem through different agricultural practices. Maize is one of the most important crop which has ranked 1st in cereals worldwide, but in Pakistan, maize has third position among the cereals after wheat and rice. It has high nutritive value. It has large number of uses in food products. Its Grain is a rich source of basic nutrients. It is rich in starch, protein, minerals and vitamins. According to the quality analysis of one hundred gram of fresh grain contain following nutrients in different amounts 361 calories of energy, 9.4 g protein; 4.3 g fat, 74.4 g carbohydrate, 1.8 g fiber; 1.3 g ash, 10.6 % water, 140 mg vitamins, 9 mg calcium, 290 mg, phosphorus and 2.5 mg iron. Maize is increasingly gaining an important position in crop husbandry because of its higher yield potential and short growth duration. It is one of important crop which provide potential production under this fluctuating climatic scenario of today. Pakistan is situated in arid to semiarid region. Due to urbanization and industrial progress, Pakistan is in list of those countries which are suffering from global warming issues. Due to global warming potential of maize production is greatly influenced. Temperature fluctuation is threatening crop production and food security near in future. In Pakistan, duration of summer is increasing and severe winter with short duration directly influencing the growth, development and yield of our major crops. Moreover, high temperatures cause early maturity of crop and also reduce the duration of source-sink relationship. Due to these phenomena, the size and weight of grain is reduced that’s ultimately result will be decrease in economic yield as well as biological yield. Due to increase in 1-1.5 °C of global temperature reduce 14-17% productivity of maize. Increase in temperature at the silking stage of maize reduces about 96-100 % yield. Rise in temperature may cause early flowering and crop maturity which show stunted crop growth and less biomass will be produce, this leads to lower the leaf area and lower photosynthetic rate. High temperature leads to early anthesis and grain filling which is also a major cause of yield reduction. The scientific research on maize provide an evidence that temperature about 35-40 °C at the stage of pollination reduce the yield up to 100-105 kg per hectare. High temperature is also response for flowering abortion and fertilization failure.
Now there is a huge challenge in front of researchers about how to overcome this thermal impact which greatly affect the crop yield. Here are some suggestions to get potential yield for maize.
- Grow highly heat stress resistance varieties. Which adapt easily the harsh climatic conditions of the present age and perform well against it and gave maximum production.
- Skip the period of crop which is highly affected by high temperature through adjustment of sowing date.
- There is need to skip the most effected crop stages to avoid the yield reduction through adjustment of appropriate time for sowing.
There are following critical stages which are greatly influenced by high temperature.
- Silking
- Flowering
- Anthesis
- Fertilization
We can get potential yield if we avoid the above mentioned crop stages by the adjustment of sowing time through experimentations. Crop growth modeling is one of the best option to predict the yield at appropriate sowing time before going to field experimentation by using the previous year’s weather data.
- Stress can be overcome through different irrigation practices.
- Encourage the agro-forestry practices to mitigate the rising heat stress problem.
- Maximum plantation should be done on barren and useless lands to discourage the global warming issue. It helps in absorption of the carbon dioxide for the photosynthesis and produces much organic matter for dependent organisms including human being. This reduces the greenhouse gas concentration in the atmosphere and makes the environment pleasant for both crops and animals.
These are some simple and easily adaptable practices through which we can obtain maximum yield near to their genetic potential of the crops.
