Effects of organic fertilizers on growth characteristics and fruit quality in Pear-jujube in the Loess Plateau

Abstract

The ecological environment of the hilly and gully area of the Loess Plateau in northern Shaanxi is fragile and the soil fertility is low. As a result, the yield and quality of Pear-jujube which constitute one of the dominant economic forests in this region, have been severely restricted. At present, the scientific application of fertilizer is important for comprehensively improving the quality of fruit trees, and for devising the optimal management of fruit trees. In particular, the application of organic fertilizers plays an important role in improving soil and improving fruit quality. In this experiment, a field study was conducted to understand the effects of different organic fertilizer applications on physiological growth, photosynthetic characteristics, reproductive growth and nutritional quality of Pear-jujube in the Loess Plateau. The results showed that organic fertilizer significantly promoted the physiological growth of Pear-jujube. The Pear-jujube bearing branch and leaf area under the soybean cake fertilizer (SC) treatment were 20.17 cm and 1246 mm2/leaf, respectively, which are increased by 34% and 44.46% compared with the no fertilizer treatment, which was a control check (CK). The total chlorophyll content of fertilization treatment was significantly higher than that of CK (P < 0.05). The maximum of chlorophyll content was 10.90 mg/dm2 under the biogas fertilizer (BM). The content of LAI was in the order BM > conventional fertilizer (CF) > sheep manure (SM) > SC > CK. The changing trend of gap fraction was opposite to that of LAI, and the density of light was consistent with that of LAI. The density of light BM was the largest, reached 38.06 mol/(m2 d), which was 15.13% higher than that of CK. Organic fertilizer significantly improved the net photosynthetic rate (Pn) and water use efficiency (WUEp) of Pear-jujube. The WUEp of SC was up to 3.30%. Organic fertilizer significantly promoted the reproductive growth and improved the nutritional quality of Pear-jujube. The yield under the SC was 19,177 kg/hm2, increased by 138.5% compared with that of CK. The fruit water content (FWC), total soluble solids (TSS), solid-acid ratio (TSS/TA), Vc and total flavonoids content improved, and the maxima of FWC, TSS, TSS/TA, Vc and total flavonoids content under the SC treatment were 86.30%, 18.48%, 40.17, 46.18 mg/kg and 14.35 mg/kg, respectively, which were significantly different from those of CK (P < 0.05). Organic fertilization effectively promotes the growth, development, yield and fruit quality of Pear-jujube in the Loess Plateau and the effect of the soybean cake fertilizer is the most significant.