Amendment with Nanoparticulate Gypsum Enhances Spinach Growth in Saline-Sodic Soil

Abstract

The use of nano-gypsum in low doses can be an innovative method to mitigate salinity-sodicity effects and enhance spinach growth in saline-sodic soil. We evaluated nano-gypsum in four low doses of 960, 480, 240, and 120 kg ha−1, in addition to the control and the recommended conventional gypsum dose (~ 30 t ha−1), in a randomized complete pot experiment. The pots of soil were incubated in a laboratory for 2 months and leached 5 times for another 2 months. Then, spinach was grown in the soil for 60 days. The nano-gypsum dose of 240 kg ha−1 with leaching was the best at improving the soil and spinach growth characteristics compared with the other doses and both control and conventional gypsum rate. Moreover, it was considered the critical nano-gypsum threshold rate. Compared to control after soil leaching, the critical rate increased the water-stable aggregate index and reduced bulk density by 57.39% and 16.30%, respectively; accordingly, the saturated hydraulic conductivity increased up to 2.34 times. Improved hydraulic conductivity led to a decrease in exchangeable Na ratio by 91% and reduced both soil salinity and pH by 83% and 1 unit, respectively. These great improvements in the soil properties favored the spinach growth indicators, which increased leaf area index, root hair index, and fresh yield by 2.20, 4.41, and 1.29 times, respectively, when compared to the recommended conventional gypsum rate. Accordingly, nano-gypsum in low doses is considered an innovative alternative to high doses of conventional gypsum to mitigate salinity-sodicity effects and enhance spinach growth in saline-sodic soil.

Nano-Management Approaches for Salt Tolerance in Plants under Field and In Vitro Conditions

“…This remediation may depend on many factors, such as soil characteristics, including mainly soil pH, EC, ESP, and the cultivated plant species or variety. In the presence of cultivated plants (spinach), nano-gypsum was a more effective alternative to traditional gypsum in mitigating salinity-sodicity effects (soil EC was 25.55 dS m −1 ) when the applied dose was 240 kg ha −1 [103]. This effective action of nano-gypsum may differ when applied in the absence of cultivated plants, as reported under applying nano-gypsum at doses up to 45%, which improved soil health by reducing soil pH, EC, and SAR during field investigation [99].…”