Pesticides Application Techology in China;
Opportunities and Challenges Co-exist
The challenges facing China are an increasing population with higher nutritional expectations and a reducing land area.
Different areas of China have different soil types and different field sizes, crops and cultural practices which means that planning agricultural production is complex.
As China matures economically, so the population expects higher quality and different foods. This adds to the complexity and increases the pressure on the agricultural community to produce more crops year on year even as the cultivated land area is reducing year by year. This pressure to produce more crops increases the requirement for pesticides.
The variations in soil types, field sizes, crops and cultutral practices also greatly increase the challenges of introducing improvements to spraying practices.
Causes for concern
The problem is that there is an imbalance between the farming systems and planting regions of China in terms of
- spraying equipment,
- application technology and
- operator training.
This imbalance means that pesticides are not applied to the same high standards across the country.
In the past 30 years, a series of new technology and machinery have been developed and used such as the low-volume, ligh, motorised knapsack spryaer, anti-drift boom sprayer electrostatic sprayer, recycle sprayer and precise sprayer. But the majority of the spraying equipment used on a family-run farm is not adequate – it cannot properly apply – modern pesticides which require careful and precise application. In 2008, 80% of the application equipment used in China were knapsack sprayers, some of which were out of date and more representative of those used in the 1960s and 1970s. Serious design problems result in drips and leaks and faults were likely to occur 6 times in any one application season. The inadequacy of spraying equipment lowers the standard of pest control in crops and has caused:
- low efficacy i.e. the capacity to control the target pest is compromised;
- pesticide residues that exceed the permitted maximum;
- environmental pollution;
- crop phytotoxicity;
- operator poisoning1
Work efficiency is very low. Single operators using knapsack sprayers can often not respond quickly enough to adequately control pests. Take for example the emergency control of locusts. The control period for locusts is 3-5 days before its migration and migration occurs in the busy farming season. As 80% of spraying equipment comprises knapsack sprayers, the operators are unable to spray against locusts in a timely way. This inability to respond has meant that locusts have caused significant damage to crops over very large areas. Similarly other pests such as cotton bollworm, wheat aphid, powdery mildew, wheat scab and rice stem borer have also caused harm over large areas of land used for food production in recent years.
and application technology
The technology of the spraying equipment is also inadequate in applying today’s advanced pesticides as precisely and as evenly as is needed. For example the cone nozzle is known to produce uneven spray patterns yet it is used on 85% of all sprayers in China even though better technology has been available for decades. For instance Occident has been using the more technically advanced
- flat-fan nozzle for the application of herbicides and plant growth regulators
- anti-drift nozzle and low drift nozzles to spray insecticide and fungicides
since the 1950s.
Where new technologies have been adopted e.g.
- low volume spraying
- ultra low volume spraying
- controlled droplet application
- recycle spraying
- anti-drift spraying
then application volumes are reduced and the effectiveness of spray transfer to target surfaces and working efficiency are improved.
Inefficient spraying causes serious problems. Large volume spraying using high water rates has resulted in pesticide spray drift and run-off where the pesticide drips from the foliage onto the ground of the treated field. The scale of this loss can be as high as 80% of that applied; a magnitude of loss that may increase risks to the environment.
Inefficient spraying is also linked to more frequent and/or higher pesticide residues than is necessary. Although the pesticide doses applied per hectare in China is the equivalent of that used in Japan, USA and Germany, pesticide residues in the produce of some family-run farms are ten times that of these countries. It is likely that although the efficiency of spraying is poor, that spray which is retained, is so poorly distributed that there are localised, over-treated areas.
Using the existing crop protection machinery and application technology has given rise to:
- Pesticide efficacy of less than 30%
- Pesticide loss of 60 – 70% and
- Pesticide distribution unevenness. Cone nozzle use, for example, on booms and adjustable nozzles on hand lances.
Inadequate equipment causes economic loss, pesticide drift and increases risks of serious environmental pollution and pesticide residues.
Operators on family-run farms are thought to be vulnerable to occupational poisoning due to low levels of operator knowledge.
Inadequate spraying machinery, application technology and operator training has resulted in
Acknowledgement and Reference
Adapted and presented here by kind permission of the Association of Applied Biologists
Xiongkui, H. (2010). The opportunity and challenge of pesticide application for agriculture and horticulture in China. Paper presented at the Aspects of Applied Biology 99, International Advances in Pesticide Application, Cambridge
1 Investigation carried out by the Ministry of Agriculture, China Agricultural University and JKI of Germany from 2006 – 2008. He, 2002; Zhang 1999; Yang, 2002; FAO, 1985, 1998 a,b
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