Naturally, haze strikes arise more concerns on China food supply and security as well as public traffic and health. In essence, haze is a kind of manifestation of air pollution with PM2.5 particles which impact human health after being inhaled. According to the monitoring data, PM2.5 concentration ranged from 457 to 520 μg/m3
across the urban and suburban area of Beijing during the ‘haze week’ occurred in 20 to 26 February, 2014. The highest record nationwide is 900 μg/m3
. Longevity of residents were supposed to be reduced when long-term exposure to high concentration PM2.5. As reported by New York Times, life expectancy of Chinese northerner was supposed to be lower at 5.5 years than the southerner.
Damage of heavy haze weather on China agriculture is noteworthy because plant-concerned sunlight traits changed drastically when it happened. It is well known that sunlight irradiation is the main energy source of plant photosynthesis
and photo morphogenesis of agricultural production. Moreover, also the heat provider to keep the temperature in protected agricultural facilities (such as Chinese solar greenhouse) during cold night. Inevitably, haze are impacting agricultural productivity negatively to an uncertain degree by decreasing photosynthesis strength for discounted light intensity (estimated beyond 50%), changed light quality and shorter photoperiod (averagely beyond 1 hour) caused by absorption and refraction of air-borne micro particles. The delay growth and development of crops in protected facilities significantly. Additionally, concentrated air pollutants may exert negative chemical impacts on plant health. Almost simultaneous with haze high-incidence season, winter and spring are prime time for high-profit protected vegetable production. The commercial yield is determinant for annual total gains of Chinese vegetable farmers. So haze strike may be fatal sometimes, determining their destiny. As investigated by author in Shiny district, Beijing, some tomato plants in Chinese solar greenhouses tend to cease growth or die under dual stresses of low temperature and weak lighting given rise to long-term haze.
Totally, the cultivation area of protected agriculture in China was estimated up to 4 million hectares. However, most of acreage is unfortunately covered by haze influential area. But the actual loss caused by haze has not investigated systematically yet. Actually, Chinese protected agriculture is facing a dilemma under frequent haze strike. Traditionally, low input and low output with low income is the characteristic and operational principle for Chinese protected agricultural production. Therefore, most of investment was used to purchase the necessary and relatively cheap supplies (e.g. seed, fertilizer, pesticide and plastic film) rather than the expensive machines or devices to control environmental factors(such as temperature, CO2
concentration and irradiation). Although Chinese solar greenhouse was invented in Liaoning province at 1980s.It is still primitive with poor environmental control capacity, highlighted contrast to well-equipped multi-span greenhouse of some developed countries, such as Netherlands and Japan etc. Furthermore, soilless cultivation is far from popularity, and soil culture accounts for over 95% at the end of 2013. So, it is inevitable and unsurprising for protected vegetables to suffer low temperature, weak light and reduced CO2
concentration stresses in China. No feasible practical strategy has been established up to now even knowing large loss paid every year for social and technological factors. That situation gets rapidly worsened intervened by haze, for further discounted light condition in agricultural facility. That means entire lifetime of Chinese protected vegetables was malnourished, striving to survive without sufficient ‘food and cloth’ conditions.