| Vegetable sweetpotato is a new type of nutritious and healthy vegetable that is highly adaptable and easy to grow,with significant therapeutic and health functions,and has gradually become an popular vegetable on the public table,especially in the summer when there is a shortage of leafy greens and the production of leafy vegetables can be a useful supplement to the summer shortage of vegetables.With the development of rooftop and balcony agriculture,growing vegetables on balconies is becoming more and more popular among urban residents.At present,most of the research on vegetable sweetpotatoes is focused on the field,and there are few reports on the study of vegetable sweetpotatoes grown in pots in balcony agriculture.In this study,the key factors of the different substrates and fertilizers affecting the growth of vegetable sweetpotato were investigated by using a new variety of vegetable sweetpotato"Shu Lv No.1"as the test material which was grown it in pots on the roof terrace.The results of the study are as follows.（1）The effects of different substrate ratios on the growth,root morphology,yield and quality of vegetable sweetpotato were determined by firstly using different volume ratios of composite substrates,grass charcoal:perlite:vermiculite:coconut bran=6:1:1:0（CK）,5:1:1:1（T1）,4:1:1:2（T2）,3:1:1:3（T3）,2:1:1:4（T4）,1:1:1:5（T5）.The effects of different substrate ratios on the growth,root morphology,yield and quality of vegetable sweetpotatoes were determined to screen the suitable substrates for potted vegetable sweetpotato.The SPAD value（leaf color value）and yield of the treatments with a high proportion of coconut bran（grass charcoal:perlite:vermiculite:coconut bran=1:1:1:5,2:1:1:4）were higher than those with a low proportion of coconut bran,and the SPAD value and yield of vegetable sweetpotato increased with the increase of the proportion of coconut bran in the cultivation substrate.The total root length,root tips number and root bifurcations of T5 and T2treatments was better than the rest,and the total surface area of T5 and T4 treatments was better than the rest;the stem thickness,petiole length,stem tip length and stem tip picking number of T5 treatment were better than the rest,and the overall quality of T5（grass charcoal:perlite:vermiculite:coconut bran=1:1:1:5）treatment was more suitable as the cultivation substrate for potted vegetable sweetpotato.（2）The slow-release fertilizer treatments were T1（N:P2O5:K2O=15-10-12）,T2（N:P2O5:K2O=25-14-12）,T3（N:P2O5:K2O=15-15-15）,T4（N:P2O5:K2O=14-13-13）,T5（N:P2O5:K2O）,using compound fertilizer as control.The effects of different slow-release fert ilizers on the growth and development,yield,quality and enzyme activity of vegetable sweetpotato were investigated to screen out suitable slow-release fertilizers for potted vegetable sweetpotato and to provide technical guidance for one-time fertilization of p otted vegetable sweetpotato during the fertility period.The test results of slow-release fertilizer for vegetable sweetpotato showed that suitable slow-release fertilizer can pro mote the growth of vegetable sweetpotato,improve the SPAD value and yield of vege table sweetpotato,and improve the quality of soluble sugar,soluble protein and vitami n C of vegetable sweetpotato.The overall growth of vegetable sweetpotato cultivated by Green Hope slow-release fertilizer was better,such as stem thickness,petiole lengt h,and stem tip picking number,and its total yield reached the highest level while the total soluble sugar,soluble protein,and VC content of vegetable sweetpotato were im proved and nitrite content was reduced.It increased SOD（superoxide dismutase）and POD（peroxidase）protective enzyme activities and decreased MAD（malondialdehyde）content during the growth period of vegetable sweetpotatoes.Therefore,the overall eff ect of applying T5 treatment with“lv pan”slow-release fertilizer was optimal and can be recommended for use in potted vegetable sweetpotato.In summary,the ratio of composite substrate and slow-release fertilizer suitable for potted vegetable sweetpotato cultivation is:grass charcoal,perlite,vermiculite,coconut bran ratio of 1:1:1:5 and“lv pan”slow-release fertilizer,which provides exploration for the development of multiple forms of soilless cultivation and also provides technical guidance for the scientific and reasonable fertilization of potted vegetable sweetpotato. |
