Effects of semi-decomposed weeds as substrate on plant growth, antioxidant capacity, and leaf nutrition of plum trees

Abstract

Sustainable practices are inevitable requirements for modern agriculture. Incorporating weed waste into an organic substrate is one of such sustainable agricultural practice. We aimed to investigate whether semi-decomposed, aboveground weed biomass can be used as a substrate for plums. “Qingcui” plums were planted in boxes with semi-composted weeds, and garden soil without composted weeds was used as a control. Plant branch characteristics, leaf antioxidant capacity, leaf nutrition, and numbers of opening flowers and bearing fruits were analyzed. The results showed that treatment with semi-composted weed treatment significantly increased the stem diameter, effective branch number, and effective branch angle. The contents of the reduced glutathione, oxidized glutathione, and the levels of total antioxidant capacity and catalase were significantly higher in semi-composted weeds than in the control group. The macroelement content in the semi-composted weed group was higher than that of the control group, but the microelement contents did not show any significant differences. However, the trace elements and heavy metals showed heterogeneous changes. The Σ DOP of macroelements, microelements, and trace elements in the weed-compost treatment were larger than that in the control. The chlorophyll content in the weed-compost group was significantly higher than that in the control during the leaf abscission period. The leaf weight per area was significantly higher than that of the control, but the growth time was longer. The numbers of total opening flowers and fruit were higher in the semi-composted weed group than in the control group. We demonstrated that semi-composted weeds as substrates have beneficial effects on plum branch characteristics, leaf antioxidant capacity, and generative growth. However, it increases the degree of nutritional imbalance and extends growth time.