| In response to the severe challenges of soil degradation,climate change and environmental pollution,there is a new type of agricultural production based on organic ecology cycling,which emerges after global agricultural green evolution.Soil health and food safety has important implications for human health.Food nutritional quality plays a fundamental and key role in human health.Selenium（Se）is a key element related to animal and human immune health.It can help human to improve human health by improving food nutritional quality and increasing selenium levels in food.Agricultural application of biochar can not only promote the health of the agricultural environment and ecosystem,but also improve soil fertility quality and the resistance of soil plant system to alleviating stress,and then achieve high-yield,high-quality and healthy crops.Biochar derived from crop residues is alkaline and rich in active organic components,which is beneficial to improve soil selenium availability and plant selenium absorption and transformation.Therefore,Combining organic selenium enrichment technology with biochar-based recycling technology is effective to construct a new type technology which can promote healthy rice production and high-quality rice supplement.In this study,a demonstration experiment of biochar-based selenium-enriched healthy rice production was carried out by using biochar and biochar-based fertilizer in the Zhishan Se-enriched Ecological Agricultural Park of Lishui District,Nanjing.Different soil treatments,including conventional compound fertilizer,biochar(15t ha-1),different biochar-based fertilizer(equivalent physical quantity,600kg ha-1)and biochar-based selenium-enriched nutrient conditioner(90ml ha-1),were applied to the soil and compared the rice disease,yield,quality,fertilizer utilization and economic benefit.The main results obtained from the experiment are as follows:（1）Compared with non-Biochar application,applying biochar can improve the soil p H,soil organic carbon,and total nitrogen content significantly by 5%～14%,6%～23%,15%-19%,respectively,which improves soil health.Applying biochar can also have significant improvement on rice quality,the disease situation of rice was greatly reduced（rice neck blast,Rice smut）and the disease situation of kitchen waste biochar treatment was reduced by about 80%;the content of beneficial trace elements Fe and Zn in the grain increased by 30%～50%and 5%～20%,respectively;the increase of iron content was the most significant in the RHB treatment and the zinc content was the most significant in the kitchen waste biochar treatment;the content of cadmium in the grain is reduced by 23%～63%,and the rice husk biochar treatment has the best effect;there is no significant improvement on the rice yield under different biochar treatment（only rice husk biochar treatment increased 7%）;（2）Compared with conventional compound fertilizers,the disease conditions of biochar-based fertilizer and biochar-based urea fertilizer fields are significantly decreased,and the disease rate is reduced by 26%～56%.The yield of rice husk biochar-based urea treatment fields decreased slightly（about 0.5%）,while other biochar-based fertilizer treatments were flat or slightly increased（the rate was less than 5%）.Therefore,carbon-based fertilizers（high nitrogen biochar-based fertilizer,rice husk biochar-based urea,rice straw biochar-based urea）with reduced total nutrients can be used as rice-based fertilizers to replace conventional compound fertilizers,which can achieve the same or slightly increase in crop yield.Biochar-based fertilizers can reduce the input of fertilizers and achieve the purpose of fertilizer loss.All Biochar-based fertilizers have significantly increased on the content of beneficial trace elements（Fe and Zn）in grains.The effect of HNBF treatment and rice husk biochar-based urea treatment are better,and the increase rate are 10～27%;Apart from rice husk biochar-based urea,all charcoal-based fertilizers improved profitability per m compared with conventional compound fertilizers;high nitrogen biochar-based fertilizer treatment and rice straw biochar-based urea treatment increased the fertilizer input-output ratio and reduced the fertilizer input per ton of rice（7%～8%）;therefore,when the price difference of rice quality was ignored,the apparent economic benefits of Biochar-based fertilizers in the area are equivalent to conventional compound fertilizers,while high nitrogen biochar-based fertilizer treatment and rice straw biochar-based urea treatment had less than 10%increase;（3）Biochar-based biological selenium enrichment conditioning and technology can increase around 3～8 times in grain selenium content with low fertilizer input,and improve nutritional quality and economic benefits.There was a huge potential and market competitiveness in the production of selenium-enriched healthy agricultural products;Above all,Biochar-based selenium enrichment technology can play an important role in the high-quality and healthy production of rice.However,it is necessary to combine the Biochar-based fertilizer which can benefit for yield increase and fertilizer decrease with organic nutrition conditioning integrated technology which includes selenium-iron-zinc nutrition,and then to achieve full health,rice safety,high-quality,and economic efficiency production. |
