Effects of different fertilizer ratios on the growth and physiology of sour pomelo seedlings

Abstract

To reduce the usage of inorganic fertilizers and to protect the soil environment, a new approach was implemented. This approach incorporated using ‘special substrate & a little inorganic fertilizer’ to study the growth of sour pomelo seedlings. There were 7 treatments, all had processed substrates, and 6 with different ratios of fertilizers as the test group and one as a control (CK), which only had processed substrate. From the experiment we discovered that all the test groups are better than CK on majority of the indicators, and W3(N:P2O5=1:0.25) was more efficient for container seedlings of sour pummelo in many aspects. For the growth parameters of W3, the average leaf area was 22.04 cm2 and the average of leaf number 26.20; for the physiological indicators, the content of chlorophyll is 62.39 SPAD, the content of soluble sugar 4.49 mg/g and the content of soluble protein 10.95 mg/g, all the different treatments of W3 were nearly significant or highly significant levels when compared to the CK (18,6 cm2, 9.6, 51.68 SPAD; 2.77 mg/g and 7.05 mg/g). Moreover, we find that the treatment which is combined with two or more fertilizers is better than the treatment with one fertilizer, so we suggest that we should choose the fertilizer ratio of N:P2O5:K2O=1:0.25 as the optimum combination.