To investigate the response mechanism and salt tolerance threshold of three willow seedlings (Salix matsudana, Salix gordejevii, Salix linearistipularis), the absorption, transport and distribution of salt ions (Na+, K+, Ca2+) were studied under hydroponic conditions with different salt concentrations (CK, 171, 342, 513, and 684 mm) and treatment times (1, 3, 5, 8, 11, and 15 days). Salix linearistipularis has the weakest ability to maintain its apparent shape, while Salix matsudana has the strongest ability. The three plants have a certain Na+ interception ability, and the interception abilities of Salix matsudana and Salix gordejevii are higher than that of Salix linearistipularis. The leaf SAK,Na of Salix linearistipularis were higher than those of Salix matsudana and Salix gordejevii. The leaf selection ability was the highest, and the selection ability of the root system was the lowest in Salix linearistipularis. The long-term low salt concentration and the short-term high salt concentration can increase the root and leaf salinity. Salix matsudana grows more stably in a long-term high-salt stress environment, and Salix gordejevii grows stably in a short-term high-salt stress environment. However, Salix linearistipularis is more suitable for planting as an indicative plant because of its sensitivity to salt stress. The root Na+ content of Salix matsudana and Salix gordejevii was 34.21 mg/g, which was the maximum root retention capacity. Once the accumulation of Na+ content in roots exceeds this value, the rejection capacity of roots is broken through, and the selective ion absorption capacity will rapidly become weak, which easily leads to the death of plants.

Ion absorption, distribution and salt tolerance threshold of three willow species under salt stress

This paper investigates the factors that influence the adoption of laser land levelers and their impact on groundwater usage in the Punjab Province of Pakistan. A farm household survey of 504 agriculture producers was conducted in 2019. A discrete‐time duration model is used to investigate factors influencing the speed of adoption and an endogenous switching regression (ESR) model is used to evaluate its impact on groundwater usage. About 70% of the surveyed households adopted the technology, and the average time to adoption was 9 years. Key factors accelerating the speed of adoption include strong legal land rights, access to information about the technology, and exposure to the technology. In contrast, long distance to rental market deaccelerates the speed of adoption. The adoption of laser land leveler reduced groundwater use by about 23%. The results imply that institutional arrangements, such as improving access to extension services, exposure to innovation, and legal land rights, can enhance the adoption and diffusion of the technology and conserve groundwater.

The adoption of laser land leveler technology and its impact on groundwater use by irrigated farmland in Punjab, Pakistan

Soil salinization is a serious environmental problem in arid and semi-arid regions, affecting crop yields and jeopardizing the food security of affected households. A common prescription to ameliorate salt-affected soils is the application of gypsum. However, little is known about the factors that motivate land managers to adopt gypsum and its likely effect on crop yields in different agro-ecological and socio-economic contexts. This study investigates the gypsum adoption process to rehabilitate irrigated salt-affected farmland, using survey data from 252 farm households in three agro-ecological zones of Punjab, Pakistan. An accelerated failure time model is used to investigate factors that affect the speed of adoption and the propensity score matching method to evaluate the impact of gypsum adoption on crop yields. About 56% of farm households adopted gypsum, and the average time to adoption was 4.3 years. Key factors reducing the time to gypsum adoption include secure and legal land entitlements, exposure to demonstration trials and field days, access to extension services, and access to credit facilities. In contrast, the distance to soil and water testing laboratories and input markets increases the time to adoption. On average, gypsum adoption increased wheat and rice yields by 17% and 23%, respectively. Our findings suggest that gypsum adoption will increase with the implementation of policies that increase land managers' exposure to the technology and formal information about the technology, reduce barriers to credit access, and provide secure and legal land entitlements.

Asjad Tariq Sheikh

Papers

What determines the time to gypsum adoption to remediate irrigated salt-affected agricultural lands? Evidence from Punjab, Pakistan