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The impact of different agronomic practices on pea adaptability to terminal drought conditions can provide increased knowledge on optimizing pea yield, biomass, and environmental footprints. Two field experiments in the layout of the split–split plot and a 3-factor (fertilizer × sowing date × seeding rate) design were carried out on pea crops in 2021 and 2022 in Kazakhstan’s dry steppe and steppe zones. The objective was to evaluate the significance of these factors and their interactions on biomass and yield based on 12 treatments in the dry steppe and 18 treatments in the steppe. In both zones, fertilizer effect on biomass and yield was significant (p < 0.05) and resulted in a biomass increase of 17% and a yield increase of 16% in the dry steppe and 19% and 17.9%, respectively, in the steppe. The sowing date’s effect on biomass and yield in both zones was also significant, with maximum yield with late sowing (20 May) and biomass increased by 10% compared to the earliest sowing date (10 May) and yield increase of 9.2% in the dry steppe, and 15.7%, and 30%, respectively, in the steppe. Seeding rate and none of the first- and second-order interactions between these three factors on biomass and yield were significant in either zone. The relationship between factors and final biomass and yield showed that fertilizer application was dominant. Our research also showed that yield was highly correlated (r = 0.8–1.0, p < 0.05) with biometric indicators of plants, such as the weight of seeds per 1 m2 and the weight of seeds per plant. The findings from this study indicate that adaptive crop production to increase the yield of peas can be used for environmental conditions of dry steppe and steppe based on the development of new agronomic practices, especially those that include fertilizer application with a combination of sowing dates.

Lettuce plants (Lactuca sativa L.) were grown under salinity stress conditions. Amino acids (histidine (His), lysine (Lys), phenylalanine (Phe), and threonine (Thr)) were individually applied to the seedlings to study their impact on the status of the photosynthetic pigments, ion absorption, proteinogenic metabolism, and peroxidase activity. Investigating the effect of exogenous amino acids on the metabolism processes showed their potential role in inducing salt stress tolerance in lettuce plants. Generally, a destructive impact on lettuce plant morphology was observed when the plants were exposed to salt stress. In contrast, the significant (p < 0.05) mitigation of salt stress was registered when EAAs were applied to the stressed seedlings while using Threonine and lysine enhanced the status of the plants under salinity stress. For the salt treatment, the maximum electric conductivity (580.2 μS/g) was reported while applying EAAs to stressed plants’ decreased EC, and the data ranged from 522 to 554 μS/g. EAAs decreased the chloride ions in the leaves by 23–30% compared to in the stressed plants. Additionally, the sodium contents were mitigated when the stressed plants were sprayed with EAAs. In contrast, applying EAAs enhanced the potassium uptake, and Thr gave the highest K+ contents (3022 μg/g). EAAs increased the chlorophyll content compared to the control except when histidine was applied, while the carotene contents significantly increased when histidine and phenylalanine were used. Endogenous amino acids are highly expressed in non-stressed lettuce plants compared to the stressed ones. Under salt stress conditions, the threonine usage increased the expression of proteinogenic amino acids except methionine and tyrosine. Compared to the salt-stressed plants, the peroxidase activity significantly decreased in the other treatments, which fell by over 32% when His, Lys, and Phe were applied.