Impact of flue gas desulfurization gypsum and lignite humic acid application on soil organic matter and physical properties of a saline-sodic farmland soil in Eastern China

Purpose

Appropriate land management is important for improving the soil quality and productivity of the saline-sodic farmland. A recent study has revealed that flue gas desulfurization (FGD) gypsum and lignite humic acid application enhanced the salt leaching and crop production. The purpose of this study was to investigate the effects of applied FGD gypsum and lignite humic acid (powder) on the soil organic matter (SOM) content and physical properties.

Materials and methods

This study was based on a field experiment of five consecutive rapeseed-maize rotations in a saline-sodic farmland soil (Aquic Halaquepts) at coastal area of North Jiangsu Province, China. The soil is sandy clay loam texture with pH of 8.43 and clay content of 185 g kg^?1. Six treatments included three FGD gypsum rates (0, 1.6, and 3.2 Mg ha^?1) and two lignite humic acid rates (0 and 1.5 Mg ha^?1). The amendments were incorporated into 0–20 cm soil depth manually every year. Soil samples were collected from each treatment and analyzed for soil organic matter, water-stable aggregates (wet sieving method), bulk density (clod method), water retention capacity (pressure plate apparatus), total porosity (calculated from bulk density and particle density), and microporosity (calculated from water content at 0.01 MPa).

Results and discussion

After 5 years, the SOM and soil physical properties were significantly (P?<?0.05) affected by the application of FGD gypsum and lignite humic acid, especially at the 0–20 cm soil depth. The highest amount of SOM with best soil physical condition was observed in the field which was treated with FGD gypsum at 3.2 Mg ha^?1 with lignite humic acid, and the SOM, total porosity (TP), microporosity (MP), mean weight diameter (MWD), water-stable macroaggregate (WSMA), and available water content (AWC) were increased by 22.8, 6.34, 23.2, 48.1, 55.5, and 15.8 %, respectively, while the bulk density (BD) was decreased by 5.9 % compared to no amendments applied. The generalized linear regression analysis showed that the SOM explained 42.9, 55.0, 48.5, and 54.2 % of the variability for BD, MWD, WSMA, and MP, respectively.

Conclusions

This study illustrates the benefits of applying FGD gypsum and lignite humic acid for increasing the soil organic matter content and improving the soil physical properties and suggests a great potential for ameliorating saline-sodic farmland soil (Aquic Halaquepts) by using combined amendment of FGD gypsum with lignite humic acid.

     

Quantitative trait loci (QTL) associated with growth rate trait in common carp (Cyprinus carpio)

Growth rate is one of the important economic traits in aquaculture species that is influenced by quantitative trait loci (QTLs). Recently published complete genetic map of common carp (Cyprinus carpio) with 307 markers (including 109 SSR, 31 EST-SSR and 167 SNP markers) was used to determine the number and position of QTLs effecting body weight (BW) and growth rate. Ten-, 11- and 12-month-old individuals of common carp were measured, and seven QTLs were detected in three linkage groups (LG1, LG6 and LG20); three were significant QTLs (qBW2-6, qBW3-6 and qBW3-20, P < 0.001), and four were suggestive QTLs (qBW1-1, qBW1-6, qBW2-20 and qBW3-1, P < 0.01). The three significant QTLs related to BW2 and BW3 were in LG6 and LG20 and covered 18 and 41 cM, respectively. The explained variances of qBW2-6, qBW3-6 and qBW3-20 were 34.4, 32.1 and 33.4 %, respectively. The four suggestive QTLs affecting BW1, BW2 and BW3 were in LG1, LG6 and LG20 and had variances that ranged from 17.9 to 26.7 %. The similarity of the QTL intervals for BW1, BW2 and BW3 in LG6 suggested that these genes may affect growth continuously during the early stage of growth and may be important for growth. The identification of QTLs for growth rate and BW in C. carpio will lead to a better understanding of the factors that influence these traits at a genetic level and will promote the growth to higher production through marker-assisted breeding.