Phosphatase activities and available nutrients in soil aggregates affected by straw returning to a calcareous soil under the maize–wheat cropping system

Abstract

The objective of this study was to investigate the effects of different rates of straw returning on soil aggregate stability, phosphatase activities, and the available nitrogen (N) and phosphorus (P) within different soil aggregate sizes. The experiment included five treatments: 1) no straw returning and no chemical fertilizer, 2) chemical fertilizer only (150 kg N ha-1, 75 kg P ha-1, and 75 kg K ha-1), 3) 20% straw returning with chemical fertilizer, 4) 60% straw returning with chemical fertilizer, and 5) 100% straw returning with chemical fertilizer. Soil samples were collected 3.5 years after the start of the experiment and separated into four aggregate sizes (<0.25 mm, 0.25–1 mm, 1–2 mm, and 2–7 mm) using the dry sieving method. Soil acid phosphomonoesterase (AcP) and alkaline phosphomonoesterase (AlP); phosphodiesterase (PD); pyrophosphatase (PrA) activities; and soil NO3−−N, NH4+−N, and resin-P were determined within soil aggregates. The results showed that straw returning rates did not significantly impact soil aggregate distribution. However, straw returning increased soil AcP, AlP, and PD in <2 mm aggregates, and high rates of straw returning led to high enzyme activities. Soil phosphatase activities were also higher in 1–2 mm aggregates. All straw returning and chemical fertilization treatments increased soil NO3−−N and resin-P concentrations but had much less effect on soil NH4+−N concentrations. Additionally, the study revealed that soil pH, the concentrations of NH4+−N, NO3−−N, resin-P, and CaCO3 significantly influenced soil phosphatase activities, but their impact varied across different sizes of aggregates.

Effect of nitrogen, phosphorus and potassium fertilization management on soil properties and leaf traits and yield of Sapindus mukorossi

“…Soil sampling: On August 20, 2023, three randomly selected sampling points in each plot, respectively, 0-20cm soil samples, soil samples collected were divided into two parts, one part of the self-sealing bag to bring back to the laboratory to naturally dry 2mm sieve, for the determination of soil chemical properties; the other part of the 50ml centrifugal tubes, with an ice box to save the soil samples, brought back to the laboratory at a low temperature of 4 °C preservation for soil microbial biomass. Soil organic carbon was determined by potassium dichromate oxidation-external heating method, available nitrogen (AN) was determined by alkaline dissolution diffusion method, soil effective phosphorus was determined by molybdenum antimony colorimetric method, Soil available potassium was determined by flame photometric method, and pH was measured by using a mixture of soil and water (1:2.5) ( Klotz et al., 2023 ; Lin et al., 2023 ). Microbial biomass carbon (MBC) and nitrogen (MBN) were measured by chloroform fumigation-K 2 SO 4 extraction method assay ( Borah et al., 2023 ; de Souza et al., 2023 ).…”

The Effects of A Novel Rice Establishment Method Combined with Wheat Straw Mulch

“…We name this as rice sowing with straw returning method (RSSR). Straw returning could increase soil organic matter (SOM) contents and available soil nutrients [5], improve soil physical properties [6], and enhance soil enzyme activities [7,8]. Due to the straw application, RSSR can also reduce the use of water and control weeds.…”