Influence of Rice Husk Biochar and Compost Amendments on Salt Contents and Hydraulic Properties of Soil and Rice Yield in Salt-Affected Fields

Abstract

Soil salinity may damage crop production. Besides proper management of irrigation water, salinity reduction can be achieved through soil amendment. The objectives of this study were to evaluate the effects of rice husk biochar and compost amendments on alleviation of salinity and rice growth. Field experiments were conducted at two salt-affected paddy rice fields located in distinct sites for five continuous crops. Treatments, with four replicates, consisted of continuous three rice crops per year (RRR), two rice crops rotated with fallow in spring–summer crop (FRR), FRR plus compost at 3 Mg ha−1 crop−1 (FRR + Comp), and biochar at 10 Mg ha−1 crop−1 (FRR + BC). Salt contents and hydraulic properties of soils, plant biomass, and plant uptake of cations were investigated. Soil bulk density (BD), exchangeable sodium (Na+), and exchangeable sodium percentage (ESP) were reduced remarkably by biochar application. Biochar application significantly increased other soil properties including total porosity, saturated hydraulic conductivity (Ksat), soluble and exchangeable potassium (K+), K+/Na+ ratio, available P, and total C. Compost application also improved BD, total porosity, and available P, but not exchangeable Na+ and ESP. Total aboveground biomass of rice showed a trend of FRR + BC > FRR + Comp > FRR > RRR. Relatively higher K+ uptake and lower Na+ uptake in rice straw in FRR + BC resulted in a significant two times higher K+/Na+ ratio over other treatments. Our results highlight that biochar amendment is a beneficial option for reducing ESP and providing available K+ and P under salinity-affected P-deficient conditions, hence improving straw biomass.

Essential Dynamics of Rice Cultivated under Intensification on Acid Sulfate Soils Ameliorated with Composted Oyster Mushroom Baglog Waste

“…Hanifa 2019) stated that plants consistently consumed N-mineral and available P until they developed towards maturity, while exchangeable K contents are particularly required in the reproductive growth stages of corn plants. Phuong et al (2020a) affirmed that the higher application dose of compost in acid sulfate soils could precisely magnify K + elements, bringing about higher exchangeable K than in unameliorated soils. Therefore, the compost amendment by 20% could give nutrients fitting to establish plant growth and meet the fertilizer prerequisites of commercial seedlings (Meng et al, 2019).…”

Influence of Rice Husk Biochar on Soil Nematode Community under Upland and Flooded Conditions: A Microcosm Experiment

“…In this study, a low rate (5 Mg ha −1 ) of biochar application did not affect the soil physicochemical properties but significantly affected ecological indices of nematodes. Previous studies also remarked that a low amount (3 Mg ha −1 to 10 Mg ha −1 ) of rice husk biochar amendment did not affect soil pH, EC, exchangeable Ca, total N, available K and soluble organic carbon in field conditions [6,72] and these amounts belong to a recommended range (5 to 50 Mg ha −1 ) by International Biochar Initiative. However, biochar can quickly shift soil microbial community [5,73] and nematodes [4,13], even at amounts that do not affect the soil chemical properties.…”

“…In recent years, biochar has been widely used and considered as a soil amendment to improve biological and physicochemical properties and crop productivity, and to mitigate environmental impacts [2][3][4]. In general, the application of biochar increases total carbon storage and reduces greenhouse gas emission [5][6][7]. Besides, biochar contributes to several key roles in biological functions by stimulating the activities and biomass of microbial communities and organisms in higher trophic levels [5,8,9].…”

Suitability of sand amended with carbonized rice husks and goat manure as a growing medium

“…As CRH ratio increases as the EC levels of a growing medium were reducing. These results might be due to the fact that CRH alone had lower levels of EC and high levels of K which thereafter provided K+ and improved physical properties which resulted in reduced Na+ and hold a lower exchangeable sodium percentage level and higher K+/Na+ ratio in the medium (Phuong et al, 2020). On another, sand alone showed low concentration levels of chemical properties which may be due to its nature of having very low concentration of these major elements while PM resulted in the best chemical properties compared to formulated media due to that it normally contains more organic matter, nitrogen and phosphorus (Atif et al, 2016).…”