What are the impacts of climate change on agricultural production
Agricultural climate refers to the climatic conditions closely related to agricultural production and crop growth and development, including the factors indispensable for crop growth and development such as light, heat and moisture, as well as unfavourable climatic conditions such as drought, waterlogging, frost and strong winds. These conditions not only affect the geographical distribution of agricultural production, but also affect the level of crop yields and the quality of the crops.
Current status and trends of China's grain production development
Over the past 40 years, China's climate has shown an overall trend of warming and drying; especially in the north, apart from parts of the middle and lower reaches of the Yangtze River and the northeast, precipitation in the eastern agricultural regions has continued to decrease. If the climate continues to develop along the above trend in the future, it will have an adverse impact on China's agriculture. Although climate change will not shake China's ability to supply its own grain, it does increase the difficulty of reaching future grain production targets, and the requirements for material inputs and technical management in agricultural production will be higher, so additional agricultural inputs will increase.
The impacts of climate change on crop yields
To study the impacts of climate change on agricultural crop yields, it is necessary to establish crop growth models that link crops with climatic factors. At present, the most commonly used model for evaluating the impact of climate change on agriculture is the DSSAT-CERES model. The data required by the model include agronomic trait parameters of crop growth, field management data, soil data, genetic parameters and daily weather data. However, there is still insufficient research evidence on the future changes of these factors.
The impacts of climate change on crop growth
Climate warming may increase crop yields because of the prolonged growing period, but after climate warming, if there is no new adaptive technology, the growing period of major crops will generally be shortened, which will have a negative effect on matter accumulation and grain yield. At the same time, the impact of increased heat resources on crop growth and development is largely constrained by changes in precipitation; if precipitation cannot increase correspondingly, it will have an adverse impact on crop growth.
The impacts of climate change on crop quality
The increase in carbon dioxide concentration will lead to a decline in crop quality. In this way, the amount of grain required per capita may have to increase in order for people to meet their own nutritional needs.
The impacts of climate change on agrometeorological disasters
The greatest impacts on agriculture come from extreme climatic conditions, such as drought, storms, heatwaves and frost. The impacts of climate change on the frequency and intensity of these climatic disasters are still poorly understood, and the degree of these impacts is still difficult to estimate accurately.
The impacts of climate change on crop pests and diseases
According to statistics, the losses caused by pests and diseases to China's agricultural output value amount to about 20-25% of the total agricultural output value. Climate warming will change the distribution areas of agricultural pests and diseases. Low temperatures often limit the distribution range of certain pests and diseases; after temperatures rise, the distribution areas of these pests and diseases may expand, thereby affecting crop growth. At the same time, the greenhouse effect also lengthens the growing season of some pests and diseases, increases the number of generations in which pests reproduce, and prolongs the period of damage within a year, so crop damage may worsen.
The impacts of climate change on the use of chemical fertilizers and pesticides
Fertilizer efficiency is very sensitive to changes in environmental temperature, especially nitrogen fertilizer. For every 1°C increase in temperature, the amount of readily available nitrogen released that can be directly absorbed and used by plants will increase by about 4%, and the release period will be shortened by 3.6 days. Therefore, in order to maintain the original fertilizer efficiency, the amount of fertilizer applied each time will increase by about 4%. Climate warming will also change the application of pesticides. As the climate warms, the crop growing season is prolonged, the number of generations in which insects reproduce in spring, summer and autumn will increase, and higher winter temperatures are also conducive to larvae surviving the winter safely. The range in which various pests and diseases appear expands, intensifying the spread of pests and diseases and the spread of weeds. This means that these areas will have to apply large amounts of pesticides and herbicides.
Conclusion: Agricultural production is a typical process in which natural and social factors act together, so the final impact assessment should consider both aspects at the same time, because the same natural change process will produce different results in societies with different economic levels. For a developing country like China, it is very important to consider the impact of socio-economic factors on the capacity to adapt to climate change.