31 / 2021-06-28 10:58:16

Effect of Different Organic Fertilizers on Soil Improvement in Continuous Orchard

Ecoenzymatic stoichiometry,Microbial metabolism,Apple replanting obstacles,Different Organic Fertilizers

Shaanxi Province is one of the two most suitable apple production areas in China(Bohai Bay Rim and Northwest Loess Plateau). However, there are also some significant problems in the rapid development of the apple industry. Most of the orchards in this region were built in the 1990s and have no longer adapted to or are gradually falling behind the market demand. Therefore, a large number of orchards will gradually enter the renewal period and have to choose to replant. The repeated cropping of fruit trees is likely to face the threat of replanting diseases. We established an experiment in 2019, using 5 experimental treatment methods: farmer habitual fertilization mode (CK), single fertilizer mode (CF), microbial inoculum combined with chemical fertilizer mode (YRCF), and organic fertilizer combined with chemical fertilizer mode ( MCF), organic fertilizer combined with microbial inoculants plus chemical fertilizer mode (MYRCF). The soil enzyme activities in three apple growth periods were determined: fruit setting period, fruit expansion period, and harvest period. The extracellular enzymatic stoichiometry model is used to check the metabolic limitation of microorganisms. The vector length and angle are used to determine the C and N/P limits of soil microorganisms. Compared with CK, the average SOC and total nitrogen (TN) content of each period under MYRCF are 6.8% and 5.4% higher, respectively. The content of SOC and TN under YRCF were reduced by 4.8% and 2.8%, respectively. Compared with CK, the C- and N-obtained enzyme activities under MYRCF are 20.5% and 5.2% lower, respectively. The alkaline phosphatase activity of MCF and MYRCF were 2.7% and 13.5% higher than that of CK, respectively. Soil nutrients, pH and temperature affect the C and P limits of soil microorganisms. By measuring soil enzyme activity and soil nutrients, it can be seen that MYRCF treatment has the best effect on improving the soil of continuous orchard.