Linking Long-Term Changes in Soil Salinity to Paddy Land Abandonment in Jaffna Peninsula, Sri Lanka

Abstract

Soil salinity is a serious threat to coastal agriculture and has resulted in a significant reduction in agricultural output in many regions. Jaffna Peninsula, a semi-arid region located in the northern-most part of Sri Lanka, is also a victim of the adverse effects of coastal salinity. This study investigated long-term soil salinity changes and their link with agricultural land use changes, especially paddy land. Two Landsat images from 1988 and 2019 were used to map soil salinity distribution and changes. Another set of images was analyzed at four temporal periods to map abandoned paddy lands. A comparison of changes in soil salinity with abandoned paddy lands showed that abandoned paddy lands had significantly higher salinity than active paddy lands, confirming that increasing salts owing to the high levels of sea water intrusion in the soils, as well as higher water salinity in wells used for irrigation, could be the major drivers of degradation of paddy lands. The results also showed that there was a dramatic increase in soil salinity (1.4-fold) in the coastal lowlands of Jaffna Peninsula. 64.6% of the salinity-affected land was identified as being in the extreme saline category. In addition to reducing net arable lands, soil salinization has serious implications for food security and the livelihoods of farmers, potentially impacting the regional and national economy.

Proofing Direct-Seeded Rice with Better Root Plasticity and Architecture

“…The problem of salinity or salt stress has been increasing gradually, resulting mostly from faulty agricultural practices (frequent light irrigation, higher use of fertilizers such as muriate of potash and ammonium sulphate and summer fallowing) [ 152 , 153 , 154 ]. The damage caused by salt stress starts right from seed germination; lower water uptake, decreased rate of photosynthesis, and consequently oxidative stress [ 155 ], which is ultimately responsible for decreased growth.…”

A Separation and Desalination Process for Farmland Saline-Alkaline Water

“…2 SDI: SDI of the saline-alkaline water and that of water yielded after pretreatment were determined using an SDI tester (model: QZDY-SD147; manufactured by Qibote Environmental Science & Technology Co., Ltd, Jiangsu, China.). 3 Total salinity: total salinity of the saline-alkaline water and that of water yielded after pretreatment were measured using a pen-type salimeter (model: AR8012; salinity measurement range: 0-50 ppt; resolution: 0.01 ppt; Smart Instruments Co., Ltd, Jiangsu, China.). 4 Pretreatment water yield: flow rates of the wastewater outlet and water yield outlet of the pretreatment device were measured using a HI2560 flow sensor (flow rate measurement range: 4-45 L/min; pile-up pulse: 1 L = 225 Hz ± 10%; manufactured by Ponai Sensor Science & Technology Co., Ltd, Zhejiang, China).…”

“…2 Total hardness: EDTA titration was used to measure total hardness of the original saline-alkaline water, water yielded by the primary and secondary RO membranes, and water yielded by the tertiary NF membrane. 3 Cl − content: Cl − contents of the original saline-alkaline water, water yielded by the primary and secondary RO membranes, and water yielded by the tertiary NF membrane were measured using an ion chromatograph (model: Integrion; chromatographic column: AS11-HC-4 µm; intelligent high-pressure ion chromatograph manufactured by Thermo Fisher Scientific Inc., Waltham, MA, USA).…”

“…Salination not only poses serious hazards to farmland soil, it also has a significant effect on crop growth environments and groundwater resources [1,2]. Saline-alkaline land formed as a result of salination has attracted global attention [3,4]. According to reports [5,6], the total global scale of saline-alkaline farmlands has reached about 800 million ha., accounting for 6% of the total area of the world's arable land.…”

Oil and Flower Production in Rosa damascena trigintipetala Dieck under Salinity Stress in Taif Region, Saudi Arabia

“…Mismanagement of agricultural lands and overexploitation of water resources in arid climates have been highlighted as some of the major causes of soil salinization [1]. In addition to reducing net arable lands, soil salinization has serious implications for food security and the livelihoods of farmers, potentially impacting the regional and national economy [2]. Salinity is one of the main limiting factors for agricultural and natural production.…”