Effects of rainfall intensity on runoff and nutrient loss of gently sloping farmland in a karst area of SW China

Abstract

Nutrient losses from sloping farmland in karst areas lead to the decline in land productivity and nonpoint source pollution. A specially tailored steel channel with an adjustable slope and underground hole fissures was used to simulate the microenvironment of the "dual structure" of the surface and underground of sloping farmland in a karst area. The artificial rainfall simulation method was used to explore the surface and underground runoff characteristics and nutrient losses from sloping farmland under different rainfall intensities. The effect of rainfall intensity on the nutrient loss of farmland on karst sloping land was clarified. The results showed that the surface was the main route of runoff and nutrient loss during the rainy season on sloping farmland in karst areas. The influence of rainfall intensity on the nutrients in surface runoff was more substantial than that on underground runoff nutrients. Nutrient loss was more likely to occur underground than on the surface. The losses of total nitrogen, total phosphorus, and total potassium in surface and underground runoff initially increased and then gradually stabilized with the extension of rainfall duration and increased with increasing rainfall intensity and the amount of nutrient runoff. The output of nutrients through surface runoff accounted for a high proportion of the total, and underground runoff was responsible for a low proportion. Although the amount of nutrients output by underground runoff was small, it could directly cause groundwater pollution. The research results provide a theoretical reference for controlling land source pollution from sloping farming in karst areas.

Impact of Land Configuration and Strip-Intercropping on Runoff, Soil Loss and Crop Yields under Rainfed Conditions in the Shivalik Foothills of North-West, India

“…A positive and strongly significant correlation (Table 2) was observed between runoff and soil and nutrient loss (NPK) suggesting that greater runoff not only erodes the soil but also results in higher dissolution of nutrients which has a perilous impact on soil fertility. Yao et al [66] also confirmed that the relationship between runoff and nutrient loss was positively significant. A negative and significant correlation was observed between cowpea yield and nutrient loss (Table 2) indicating that a decrease in soil nutrients due to erosion impairs crop performance through reduced underground and aboveground biomass.…”

Effects of Three Rainfall Patterns on Soil Chemical Properties in Black Pepper Cultivation in a Hilly Topography

“…However, it decreased again to 4.36 in December, representing lower Ca availability due to the dilution effect replacing H + . Acidic conditions, including frequent rainfall and intensity, will intensify leaching occurrence, and liming will displace aluminium ion (Al 3+ ) and manganese ion (Mn 2+ ) from soil colloids then precipitate in soil solution (Goulding, 2016;Hess et al, 2020;Yao et al, 2021). Additionally, liming on sandy soil has proven the low mobility, minimum reaction, and lack of soluble by-product (anions) of reaction with acidity (Meda et al, 2002;Nunes et al, 2019), evident by small pH increments.…”

The Ubiquitin Proteasome System and Nutrient Stress Response

“…Water logging increases soil leaching resulting in loss of nutrient cations and salts, as well as higher soil acidification ( Karmakar et al, 2016 ; Gelybó et al, 2018 ). Erosion caused by heavy rainfall also depletes soil nutrients ( Yao et al, 2021 ). Plants have an optimal soil pH range for maximum growth, and pH above or below this range has been shown to influence nutrient uptake and content ( Islam et al, 1980 ; Haynes and Swift, 1986 ; Neina, 2019 ).…”