| Selenium(Se) is an essential nutrient element for human, and Se deficiency causes a variety of human diseases. Food is the main way to supply the body’s Se nutrition, so it is of great significance to study the technology of Se-rich agricultural products and to enhance the Se content of agricultural products for improving the level of human health and preventing diseases. In this paper, screening of Se-enriched rice genotypes and Se fertilizer application technology for rice and fruits were studied by soil pot experiment and field investigation and experiment, aiming to provide the theoretical basis and means for production the Se-rich agricultural products. The main results are summarized as follows:1. Soil pot experiments were conducted to study the uptake and distribution of exogenous Se in different genotypes of rice to screen efficient Se-enriched rice genotypes. The results showed that when the soil contained 3 mg/kg Na2 Se O3 the rice accumulated 0.12~0.58 mg/kg of Se which reached the national standard for Se-enriched rice. Three selected Se-enriched rice genotypes were Wuyou 308, Guangliangyou 308, and Pearl glutinous, which contained the Se of 0.58, 0.39 and 0.37 mg/kg respectively, and were 383%, 225% and 208% respectively more of Efufengyou-11, the least Se content rice genotype. Yliangyou No.1 and Wuyou 308 were selected as the Se-enriched genotypes by foliar spraying Se fertilizer, both the Se content was 0.08mg/kg, which was four times that of Shenliangyou 5814, the least Se content rice genotype.2. In order to select the best foliar fertilizer formula and technology for foliar application of Se in rice, the effect of different formulations of foliar fertilizers on rice Se accumulation and utilization were studied by field experiments in low Se soils in both Jiangxia and Ezhou. The results showed that the Se content of rice in all Se-treatments reached the national Se-enriched standard when spraying 1.5 g Na2 Se O3 per 667 m2. Addition of synergist significantly increased the Se content in grain. The best foliar fertilizer formula was sodium selenite + PA(300μM) combined with 0.05% HF synergist. With this treatment, the Se content in grain was 0.326 mg/kg, increased by 326% against the non-selenium fertilizer control, and by 210% against the sodium selenite only. Besides, foliar applying 100 g Zn SO4+ 0.1% HZ + 0.2% urea resulted in 17.82 mg/kg Zn content in grain, 40% more than the control; and foliar applying 100 g Fe SO4.7H2O+ EDTA+0.1% HM +0.2% urea resulted in 14.80 mg/kg Fe content in grain, 57% more than the control.3. Field experiments were conducted to study the Se absorption and application techniques of rice in low Se soils(Zhangxiang, Fengcheng, Jiangxi Province). Two ways of Se application were selected, one was soil Se-supplement with compound fertilizer, and the second was foliar spraying Se fertilizers. The results showed that the Se application improved the content of Se in different parts of rice. The more Se fertilizer applied, the higher content of Se in rice. The least amount of Na2 Se O3 fertilizer was 20 g per 667m2, and the content of Se in rice was 0.067mg/kg.4. Field experiments were conducted to study the absorption and application techniques of Se of rice in Se-enriched soil areas(Dongjia, Fengcheng, Jiangxi Province). The results showed that Se content in rice by application of microbial phosphatesolubilizing chlorella was 0.091 mg/kg, increased by 97.83% against the control. Foliar Se fertilization significantly improved the Se content in different parts of rice, with the Se content of rice by 23% more than that of no silicon addition.5. The abundance index of soil Se fertility was studied in Fengcheng, Jiangxi. The results showed that the Se content of rice and soils were significantly positively correlated. The linear correlation formular between rice total Se(Y) and soil total Se(X) was Y = 0.1731 X + 0.0048, R2 = 0.662.6. Field studies were carried out in a 5-year-old plum field in order to explore the best Se fertilizer formulation and application techniques. The results showed that Se content of the fresh plums was about 0.01~0.026 mg/kg after foliar spraying Se fertilizers, surpassing the Hubei Se-rich standard for fruits and vegetables(>0.01mg/kg). The best Se fertilizer application rate was 6 ~ 12 g / 667 m2. Spraying zinc fertilizer significantly increased the zinc content of plums, the best formula was Zn SO4100 g + synergist HZ and urea per 667 m2, with the Zn content increase by 451 % compared to the control. Fe SO4.7H2O100 g per 667 m2 was the best formula, with the iron content increase by 24% compared to the control.7. Se-rich fertilizer formulas and application techniques were studied in 5-year-old citrus by both foliar spraying and soil application, in order to find out the best Se fertilizer formulation and application techniques. The results showed that the content of Se for fresh citrus was 0.003~0.007 mg/kg after foliar spraying. Foliar spraying Se fertilizer for citrus had just reached the standard of Se-rich fruits, but soil application of Se did not. The results confirmed that foliar application of Se was the better technique than soil application. Application of zinc and iron fertilizer formula for citrus according to the optimal formula of plum, compared with controls, the citrus zinc content increased by 93 times, the citrus iron content increased by 6%. |
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