The Effects of Plastic Mulching Combined with Different Fertilizer Applications on Greenhouse Gas Emissions and Intensity, and Apple Yield in Northwestern China

Abstract

Plastic mulching reduces weeds, conserves soil water, and boosts crop yield. However, most studies are insufficient when determining how plastic mulching affects greenhouse gas (GHG) emissions, particularly when used in conjunction with fertilizers. The purpose of this study was to determine the combined effect of plastic mulching and fertilizers on GHG emissions in apple orchards. A 3-year field experiment was conducted with two factors: mulching and fertilizers; (1) mulching treatments: plastic film (PM) and no mulching (NM); and (2) four fertilizer treatments: control (CK), organic fertilizer (M), inorganic fertilizer (NPK), and organic combined with inorganic fertilizer (MNPK), arranged in a two factorial randomized complete block design. The results showed that the mean annual N2O emissions ranged from 0.87 to 5.07 kg ha−1 in PM and from 0.75 to 2.90 kg ha−1 in NM. The mean CO2 emissions ranged from 2.10 to 6.68 t ha−1 in PM and from 1.98 to 4.27 t ha−1 in NM. MNPK contributed more to N2O and CO2 emissions in both PM and NM. The mean CH4 uptake rate ranged from 1.19 to 4.25 kg ha−1 in PM and from 1.14 to 6.75 kg ha−1 in NM. M treatment contributed more to CH4 uptake in both PM and NM. NKP treatments had higher greenhouse gas intensity (GHGI) in PM and NM, while MNPK and NPK treatments had higher greenhouse gas potential (GWP) in PM and NM, respectively. These results suggest that plastic film mulching significantly raises the potential for soil GHG emissions and increases apple yield.