Investigation and Research on the Current Status of Fertilization in Facility Vegetables of Shandong Province

In order to clarify the current situation and main problems in facility vegetable fertilization and guide farmers to fertilize scientifically,an investigation on the yield and fertilization of facility vegetables( tomato,cucumber,eggplant and celery) was carried out in six districts and counties in Shandong Province from 2016 to 2017. The results showed that among the four vegetables,the yield levels of eggplant and celery varied slightly with the coefficient of variation between 7. 18% and 27. 63%,and the yield levels of tomato and cucumber varied greatly with the coefficient of variation between 33. 84% and 65. 15%. In terms of fertilization,the differences in N,P2O5 and K2O inputs in cucumber was the largest,and the maximum values of the nutrient inputs were 7. 95,8. 54 and 8. 77 times of the corresponding minimum values,respectively. The input amounts of N,P2O5 and K2O in tomato,cucumber and eggplant were 1. 47-2. 68,3. 93-7. 50 and1. 09-1. 51 times of the corresponding demands,respectively. The N and P2O5 inputs of celery exceeded the demands by 32. 00% and 79. 00%,respectively,while the K2O input was only 49. 00% of the demand. The ratios of N∶ P2O5∶ K2O input in the total application amount,organic fertilizer,base fertilizer and topdressing chemical fertilizer of facility vegetables were,respectively,1∶ 0. 84∶ 1. 02,1∶ 0. 84∶ 0. 80,1∶ 0. 99∶ 1. 05 and 1∶ 0. 77∶ 1. 25. The proportion of P2O5 input was too high,while the proportion of K2O input coming from the organic fertilizer was insufficient. The average proportions of organic fertilizer in N,P2O5 and K2O inputs were 43. 96%,43. 72% and 36. 99% respectively. The proportions of organic fertilizer in N and P2O5 inputs were reasonable,while that in K2O was lower.In N,P2O5 and K2O inputs of different vegetables,the proportions from organic fertilizer were reasonable in cucumber,higher in eggplant and lower in tomato and celery. The recommendations were presented in this paper that the inputs of N and P2O5 should be reduced,and the inputs of K2O and organic fertilizer should be increased,while farmers should choose fertilizer with low P2O5 and high K2O contents.

A Study on Remediation Technologies for Cadmium Contamination in Greenhouse Vegetable Fields

Based on the literature and experimental results, three kinds of amendments, namely, rice biochar, hydroxyapatite and potassium dihydrogen phosphate(KH2PO4), and deeper ploughing were selected to evaluate the field application effect of soil amendments and agronomic measures on the remediation of Cd contamination in greenhouses. Cd-contaminated greenhouse screening was conducted from 2015 to 2017. In September 2017, comparative tests of eight treatments were performed in September 2017, and a selective test was performed in September 2018. The results of the screening of contaminated areas indicated that the distributions of over-standard sites and Cd content were significantly different. Greenhouse No. 4, in which the highest over-standard rate was 83.33% and the average content of Cd in soil was 0.535 mg/kg, was used as a comparative test experimental site for eight treatments. Greenhouse No. 1 was selected as the optimum test greenhouse for selective testing, with three plots having average Cd concentrations of 0.530, 0.568 and 0.792 mg/kg. The 8 months following comparative treatment showed that the content of available Cd following the treatment of rice biochar+hydroxyapatite+deeper ploughing(treatment T6) was reduced by 32.55% and 24.96% compared with the CK(the control) and 2 months following treatment, respectively. The content of available Cd using rice biochar+KH2PO4+deeper ploughing(treatment T7) treatment decreased by 47.88% and 31.00% compared with the CK and 2 months following treatment. The selective test results showed that in rice biochar+hydroxyapatite+deeper ploughing: the total Cd content of decreased from 0.489 to 0.372 mg/kg(23.86% lower), compared with the CK, and the mean content of available Cd decreased by 10.71% after 8 months, which was the lowest available Cd measured(0.133 mg/kg). In addition, the bean plant Cd content, bioconcentration factor(BCF) and translocation coefficient(TF) decreased by 15.86%, 23.68% and 25.77%, respectively. Rice biochar+hydroxyapatite+deeper ploughing is a favoured technology for the remediation of Cd-contaminated protected vegetable fields.

Effect of Combined Foliar Spray on Heavy Metals Accumulation in Facility Fruit Vegetables

In order to explore the effects of combined foliar spray which was prepared from potassium fulvate and Zn on heavy metal accumulations in three kinds of facility fruit vegetables,cucumber,tomato and white melon,the foliar spray was applied from fruit setting to maturation.The results showed that the combined foliar spray significantly promoted the absorption of Zn and Cu in the three fruit vegetables,blocked the absorption of Cr,As and Pb in cucumber,significantly blocked the absorption of Cd in white melon,blocked the absorption of Pb in white melon,and showed a tendency of blocking the absorption of heavy metals Cd and As in tomato.