Evaluation of best management practices with greenhouse gas benefits for salt-affected paddy soils in South Asia

Abstract

Anthropogenic climate change has caused increased soil salinity in South Asia due to saltwater intrusion caused by sea level rise, input of fertilizers with high salt index, and irrigation malpractices, etc. Salinity has a multitude of impacts on plant and soil processes, leading to alterations in gas fluxes and rice productivity. The remedial measures adopted on salt-affected soils to reduce the salinity effect could enhance future climate change if they cause an increase in greenhouse gas (GHG) emissions. This study was conducted to find the best agricultural management practices (BMPs) for salt-affected soils in rice cropping systems (i.e. the major cropping system in Asia) in four South Asian countries (Sri Lanka, India, Bangladesh and Pakistan) considering net GHG emissions and other socioeconomic benefits associated with the adopted measures. The salinity-affected sites were selected based on available information (e.g. agricultural statistics and maps). Site-level measurements on soil parameters and GHG emissions were made in control- and managed plots and farmer surveys were conducted. Although organic amendments ameliorated salinity, it could cause a net increase in carbon dioxide or methane emissions depending on the soil conditions, particularly during the initial stages. This impact could be ameliorated by combining organic amendments with other management practices. In the Indo-Gangetic region, poor soil drainage causing anaerobic conditions favoured nitrous oxide emission under low to medium salinity. Yield losses and emissions in high salinity sites were controlled through organic amendment, irrigation and rice-fallow cropping sequence. The combination of transplanting of rice seedlings, the addition of organic matter, and intermittent irrigated water levels was identified as the BMP for Sri Lankan farmers. The outcome of this project will be used to raise awareness among farmers and policymakers.

Field Crop Responses and Management Strategies to Mitigate Soil Salinity in Modern Agriculture: A Review

“…Other factors, i.e., water shortage, rainfall limitations, and high evapotranspiration, induced soil salinity in various regions of the globe [27,28]. A high concentration of salts in the soil solution can negatively affect the uptake of water and essential nutrients, reduce plant growth and development, and alter the physiochemical processes (Figure 2) [6,28,29]. The first effect of salinity stress on plants is osmotic, while the second effect is ionic.…”

“…The primary germination stage is the most critical process in the seedling establishment [6]. Soil salinity usually delays or even prevents seed germination [29]. Seed imbibition is affected by a high concentration of salts in the soil, reducing the water uptake by decreasing soil osmotic potential [35,36].…”

How Does Zinc Improve Salinity Tolerance? Mechanisms and Future Prospects

“…Germination is the most important and crucial stage of plant life [ 41 , 42 ]. However, SS reduces water uptake by decreasing soil osmotic potential [ 43 , 44 ] and altering the synthesis of proteins and energy production [ 43 ].…”

“…Zn directly protects membranes from oxidative damage owing to the fact that it is a vital component of important enzymes, and it also stabilizes proteins’ Zn fingers [ 41 ]. Zn is a vital component of SOD and Cu/Zn isoforms that play an important role against oxidative stress.…”

The critical role of nitrogen in plants facing the salinity stress: Review and future prospective

“…Soil salinization is foremost noxious among all other abiotic stresses affects plant growth, yield and grain quality indices (Chaudhry and Sidhu, 2022). Seed germination is imperative stage significantly affected with reduced water imbibition due to less soil osmotic potential in saline soil (Debez et al, 2020;Lokupitiya et al, 2020;Mwando et al, 2020;Krichen et al, 2023). Salinity caused ion toxicity in embryo that alters the protein metabolism, decreased the adenosine triphosphate (ATP) generation and hormonal regulation that significantly reduced the germination percentage of a crop in salt affected soils (Bilkis et al, 2016;El-Hendawy et al, 2019;Bagwasi et al, 2020).…”