Salicylic acid (SA) and proline exhibit protective effects against a wide range of stresses. However, the combined impact of SA and proline on rice under drought stress is still unknown. Therefore, we investigated the protective roles of SA and/or proline in conferring drought tolerance in rice. There were eight treatments comprising the control (T1; 95–100% FC), 1.5 mM SA (T2), 2 mM proline (T3), 0.75 mM SA + 1 mM proline (T4), 45–50% FC (T5, drought stress), T5 + 1.5 mM SA (T6), T5 + 2 mM proline (T7), and T5 + 0.75 mM SA + 1 mM proline (T8), and two rice varieties: BRRI dhan66 and BRRI dhan75. Drought stress significantly decreased the plant growth, biomass, yield attributes, photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), photosynthetic pigments (chlorophyll and carotenoids content), relative water content (RWC), membrane stability index (MSI), soluble sugar and starch content, and uptake of N, P and K⁺ in roots and shoots. Drought-induced oxidative stress in the form of increased hydrogen peroxide (H₂O₂) production and lipid peroxidation (MDA) was observed. The combined application of SA (0.75 mM) + proline (1 mM) was found to be more effective than the single application of either for drought stress mitigation in rice. A combined dose of SA + proline alleviated oxidative stress through boosting antioxidant enzymatic activity in contrast to their separate application. The application of SA + proline also enhanced proline, soluble sugar and starch content, which resulted in the amelioration of osmotic stress. Consequently, the combined application of SA and proline significantly increased the gas exchange characteristics, photosynthetic pigments, RWC, MSI, nutrient uptake, plant growth, biomass and yield of rice. Therefore, the combined application of SA and proline alleviated the detrimental impacts of drought stress more pronouncedly than their separate application did by increasing osmoprotectants, improving nutrient transport, up-regulating antioxidant enzyme activity and inhibiting oxidative stress.

Reliance on inorganic fertilizers with less or no use of organic fertilizers has impaired the productivity of soils worldwide. Therefore, the present study was conducted to quantify the effects of integrated nutrient management on rice yield, nutrient use efficiency, soil fertility, and carbon (C) sequestration in cultivated land. The experiment was designed with seven treatments comprising of a zero input control, recommended inorganic fertilizers (RD), poultry manure (PM) (5 t ha⁻¹) + 50% RD, PM (2.5 t ha⁻¹) + 75% RD, vermicompost (VC) (5 t ha⁻¹) + 50% RD, VC (2.5 t ha⁻¹) + 75% RD, and farmers’ practice (FP) with three replications that were laid out in a randomized complete block design. The highest grain yield (6.16–6.27 t ha⁻¹) was attained when VC and PM were applied at the rate of 2.5 t ha⁻¹ along with 75% RD. Uptake of nutrients and their subsequent use efficiencies appeared higher and satisfactory from the combined application of organic and inorganic fertilizers. The addition of organic fertilizer significantly influenced the organic carbon, total carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, soil pH, phosphorus, potassium, sulfur, calcium, and magnesium contents in post-harvest soil, which indicated enhancement of soil fertility. The maximum value of the organic carbon stock (18.70 t ha⁻¹), total carbon stock (20.81 t ha⁻¹), and organic carbon sequestration (1.75 t ha⁻¹) was observed in poultry manure at the rate of 5 t ha⁻¹ with 50% RD. The soil bulk density decreased slightly more than that of the control, which indicated the improvement of the physical properties of soil using organic manures. Therefore, regular nourishment of soil with organic and inorganic fertilizers might help rejuvenate the soils and ensure agricultural sustainability.

Tomato is affected by various biotic and abiotic stresses, especially salinity, which drastically hinders the growth and yield of tomato. Calcium (Ca) is a vital macronutrient which plays physiological and biochemical roles in plants. Hence, we studied the protective roles of Ca against salinity stress in tomato. There were eight treatments comprising control (nutrient solution), 5 mM Ca, 10 mM Ca, 15 mM Ca, 12 dS m⁻¹ NaCl, 12 dS m⁻¹ NaCl + 5 mM Ca, 12 dS m⁻¹ NaCl + 10 mM Ca and 12 dS m⁻¹ NaCl + 15 mM Ca, and two tomato varieties: BARI tomato-2 and Binatomato-5. Salinity significantly decreased the plant-growth and yield attributes, relative water content (RWC), photosynthetic pigments (SPAD value) and the uptake of K, Ca and Mg in leaves and roots. Salinity-induced oxidative stress was present in the form of increased Na⁺ ion concentration, hydrogen peroxide (H₂O₂) content and lipid peroxidation (MDA). Ca application reduced oxidative stress through the boosting of antioxidant enzymatic activity. Exogenous Ca application enhanced proline and glycine betaine content and reduced Na⁺ uptake, which resulted in the inhibition of ionic toxicity and osmotic stress, respectively. Hence, Ca application significantly increased the growth and yield attributes, RWC, SPAD value, and uptake of K, Ca and Mg. Calcium application also had a significant effect on the fruit quality of tomato and the highest total soluble solid, total sugar, reducing sugar, β-carotene, vitamin C and juice pH were found for the combined application of NaCl and Ca. Therefore, application of Ca reversed the salt-induced changes through increasing osmoprotectants, activation of antioxidants enzymes, and by optimizing mineral nutrient status.

Adequate supply of micronutrients is important for the proper growth and yield of lentil, particularly in poorly fertile soil. This study was carried out to understand the effects of zinc (Zn), boron (B), and molybdenum (Mo) on the growth and yield of lentil, and how these elements can help manage soil fertility issues. In this regard, the morpho-physiological traits of lentils (BARI Masur-7) were collected from two experiments receiving the same treatments carried out during consecutive rabi seasons of 2015–2016 and 2016–2017. The experiments were laid out with a randomized complete block design having eight treatments, and was replicated thrice. The treatments were T₁ (Control), T₂ (Zn_2.0 kg ha⁻¹), T₃ (B_1.5 kg ha⁻¹), T₄ (Mo_1.0 kg ha⁻¹), T₅ (Zn_2.0B_1.5 kg ha⁻¹), T₆ (Zn_2.0Mo_1.0 kg ha⁻¹), T₇ (B_1.5Mo_1.0 kg ha⁻¹), and T₈ (Zn_2.0B_1.5Mo_1.0 kg ha⁻¹). The results revealed that the application of micronutrients either singly or in combination had significant effects on the plant height, number of branches per plant, number of pods per plant, number of seeds per pod, thousand seed weight, and the seed yield of lentil. The maximum seed production was, however, observed in plots receiving treatment T₈, i.e., the combined application of Zn, B, and Mo. Agronomic biofortification also had significantly increased protein content of lentil seeds while affecting the macro and micronutrient content of lentil seed. These results suggest that any micronutrient deficiencies might lead to a yield loss of lentil, and such a scenario could be avoided by a combined application of micronutrients at a proportionate level.

Wheat growth, development and yield are severely affected by a wide range of abiotic stresses, and salt stress is a vital and increasing abiotic stress. Salicylic acid (SA) is a phenolic phytohormone involved in plant physiological processes. Hence, we have conducted an experiment to explore the roles of exogenous SA in mitigating salt stress in two wheat genotypes. There were eight treatments comprising (i) control, (ii) 0.5 mM SA, (iii) 1.0 mM SA, (iv) 1.5 mM SA, (v) salinity (12 dS m⁻¹), (vi) salinity + 0.5 mM SA, (vii) salinity + 1.0 mM SA and (viii) salinity + 1.5 mM SA with two wheat genotypes viz G 200-4 and BARI gom-25. The experiment was laid out in a completely randomized design with five replications. During the vegetative stage, salt stress significantly reduced the relative water content (RWC), photosynthetic rate, stomatal conductance and growth characteristics of both wheat genotypes, while the exogenous application of SA in salt-stressed plants significantly improved the RWC, gas exchange activities and growth performance of both the genotypes. The leaf chlorophyll content was also degraded due to salinity treatment, although it was mitigated by the exogenous application of SA. The imposition of salt significantly reduced the number of days required for maturity, yield-contributing characteristics and the yield of both the wheat genotypes. Salt stress also significantly increased Na⁺ concentrations and the Na⁺/K⁺ ratio, while the K⁺ concentrations was decreased significantly in both the wheat genotypes. However, the exogenous application of SA in salt-stressed plants significantly reduced the salt stress effects and increased the growth and yield of wheat genotypes by enhancing RWC, gas exchange activities and photosynthetic pigments and maintaining lower Na⁺ concentrations and a Na⁺/K⁺ ratio. Therefore, the findings of this study suggested that the exogenous application of SA improved the salt tolerance of both wheat genotypes.

Wheat is affected by various biotic and abiotic stresses, especially salinity, which reduces the growth and yield drastically. With this view, an experiment was conducted to observe genotypic differences in agro-morphological, yield, and biochemical responses to salinity. Experimental variables consisted of five salt-tolerant genotypes (G 13, G 20-1, G 9, G 22, G 20-2), one susceptible genotype (G 24) and one standard check variety (BARI ghom 25), which assigned to four levels of salinity with electrical conductivities 0, 4, 8 and 12 dS m⁻¹. Irrespective of genotypes, salinity stress significantly decreased the yield and yield attributes. However, maximum total tillers plant⁻¹, effective tillers plant⁻¹, number of grains spike⁻¹, and grain yield plant⁻¹ was found in salt tolerant genotype G 20-2, followed by genotypes G 13, G 20-1, and the lowest was observed in salt-susceptible genotype G 24. The lowest reduction percentage of yield and yield attributes were also observed in salt tolerant genotype G 20-2 followed by genotypes G 13, G 20-2, and the maximum reduction percentage was found in salt-susceptible genotype G 24. Results showed that the highest amount of proline, glycinebetaine, soluble sugar and soluble protein content were observed in salt-tolerant genotype G 20-2, followed by genotypes G 13, G 20-1, and the minimum was found in salt-susceptible genotype G 24. On the other hand, the lowest hydrogen peroxide (H₂O₂) and melondealdehyde (MDA) accumulation was detected in the same salt-tolerant genotype G 20-2, followed by G 13, G 20-1, and the maximum was observed in salt-susceptible genotype G 24. Therefore, higher accumulations of compatible solute in the tolerant genotypes reduce the oxidative stress, and provide the higher yield.