Understanding the influence of precipitation and nitrogen depositions on the soil health and growth indices of invasive (Solidago canadensis L.) and native (Wedelia chinesis) association

Abstract

Abstract Climate change has impacted plant community sustainability and increased the risk of plant invasion. Variable precipitation patterns and nitrogen (N) deposition rates have influenced plant community structure and productivity in different ecosystems. These factors have important implications for ecosystem functioning and biodiversity in the face of climate change. The current study investigates the effects of precipitation levels and N deposition rates with various cropping system on soil and the growth indices of native WC (Wedelia chinesis (Osbeck) Merr.) and invasive SC (Solidago canadensis L.) plants. Two different pot experiments were conducted in a greenhouse. In the first experiment, three levels of precipitation (low precipitation (PL), normal precipitation (PN) and high precipitation (PH); while in N deposition experiment: three levels of N deposition (N0 (no application), N5 (5 g m− 2 yr− 1) and N10 (10 g m− 2 yr− 1)) were evaluated with different cropping systems (bare pot as control (CK), invasive monocropping (SC), native monocropping (WC) and intercropping (SC ×WC)). Both experiments were executed in CRD-factorial design with five replications. During the experiment, soil chemical properties and growth index parameters were collected monthly. The precipitation experiment results showed that PL increased the soil NH4 +-N content in the native monocropping system, While, the maximum NO3 −-N content with application of PN as compared with control treatment (CK). Besides this, normal precipitation increased the total organic carbon (TOC) concentration with invasive monocropping by 59% and 70% during August and October month, respectively. Highest soil pH was recorded at combined application of normal precipitation and intercropping of native and invasive. The PN increased the growth index (chlorophyll content and plant height) and wet and dry biomass of shoots (53% and 45%) and roots (66% and 75%). Moreover, the maximum growth index and wet and dry biomass of shoots (49%) and roots (72% and 75%) were noticed in invasive monocropping cropping system. Furthermore, N depositions experiment results indicated that the addition of N (N10) increased the concentration of NH4 +-N in intercropping of native and invasive plants during October and December. Similarly, the higher rate of N deposition (N10) increased the soil NO3 −-N content in invasive monocropping during August and October. Whereas, appropriate application of N rate (N5) in combination with invasive monocropping increased the TOC concentration by 44% in December. The addition of N10 enhanced the growth index and wet and dry biomass of the roots (65% and 54%) and shoots (70% and 55%). Overall, PN, and increased of N deposition rate (N10) favored the growth of invasive plants. This may increase the risk of plant invasion and have adverse impacts on native plants.

Keywords

• Precipitation level
• N deposition
• Cropping system
• Soil health
• Growth index