Combined Application of Organic and Inorganic Fertilizers Effects on the Global Warming Potential and Greenhouse Gas Emission in Apple Orchard in Loess Plateau Region of China

Abstract

Inorganic fertilizers have been widely used to achieve high apple yields throughout China, especially in Northwest China. This approach has adverse effects on apple orchard soil environments and greenhouse gas (GHG) emissions. Therefore, we investigated the effects of combined organic and inorganic fertilizers on GHG emissions, soil properties, and apple yield to assess the greenhouse gas inventory and to determine which fertilization manner is good for the sustainable development of apple orchards. A split plot design was used, with main treatment of fertilizer ditch (FD) site and a bare soil (BS) site, each with four subtreatments: organic fertilizer–goat manure (M), chemical fertilizer (NPK), chemical fertilizer combined with organic fertilizer–goat manure (MNPK), and control (CK). The cumulative N2O emissions at the FD site were higher than those at the BS site (by 105.72%). The N2O emissions ranged from approximately 0.95–5.91 kg ha−1 and were higher in the MNPK treatment than in the other treatments. The cumulative CH4 uptake from each treatment was generally negative (1.06–7.67 kg ha−1). Compared to the other treatments, the MNPK treatment applied at the FD site led to an increased global warming potential. At both the FD and BS sites, the MNPK treatment led to a lower greenhouse gas intensity than the NPK treatment. Nitrates nitrogen (NO3−-N), water-filled pore space, and temperature all influenced GHG emissions. These results showed that the MNPK treatment was more conducive than the other treatments to the sustainable development of apple orchards in the Loess Plateau region of China.