Effective use of salt affected soils needs the development of the most efficient and suitable reclamation technology to optimize farm management and better crop yields. Different chemical methods and amendments are used to reclaim the salt affected soils and after reclamation such soils may be used for sustainable agricultural production. Choice of a chemical amendment depends on its availability, cost, handling and time of application. Application of sulfur is very effective technique to suppress the uptake of undesired toxic elements and to improve the quantity and quality of produce in salt affected soils. So, a three-year field experiment was carried out to evaluate the comparative reclamation efficiency of two sulfur sources, i.e elemental sulfur and gypsum to improve the soil conditions by reducing the salinity/sodicity impact and yield characteristics of rice and wheat crop. A saline-sodic field {(EC e = 6.10 dS m -1 , pH s = 9.21 and SAR = 41.67 (mmol L -1 ) 1/2 , SO 4 -S = 16.0 (mg kg -1 ) and soil gypsum requirement (SGR) of 9.10 t ha -1 for 0-15 cm soil depth} was selected. The treatments included were: control, gypsum application @ 100 SGR, S application @ 25, 50, 57, 100 and 125 % of SGR. Statistical analysis of three-year pooled data showed that varying levels of sulfur and gypsum significantly improved soil properties and rice-wheat yield than control, however, gypsum @ 100% of soil GR was at par with S @ 125 and 100% of SGR in term terms of improving yield component of both test crops and reducing soil pH s , EC e and SAR. Efficiency of treatment could be arranged as gypsum @ 100% SGR = S @ 125 % of SGR= S @ 100% of SGR> S @ 75 % of SGR> S @ 50 % of SGR> S @ 25% of SGR>control.

ABSTRACT. Amelioration of salt-affected soils requires an integrated management approach, which not only improves their effectiveness for improving soil properties, but also increases the crop production and quality of the produce. Hence, a study was planned to evaluate combined use of organic and inorganic amendments for better rehabilitation of salt affected soil in ricewheat cropping sequence from 2013 to 2016. Treatments included T 1 -control, T 2 -gypsum @ 100 SGR, T 3 -CaCl 2 @ 50% SGR, T 4 -CaCl 2 @ 50% SGR + biogas slurry @ 10 tˑha for wheat (Inqlab-91) and 110-90-60 NPK kg ha -1 for rice (Shaheen Basmati) was applied. Soil samples were collected before application of amendment and after harvesting of each crop. Straw and grain/paddy yield data were recorded at maturity. Pooled data showed that grain/paddy and straw yield of wheat and rice crop was higher in T 2 (gypsum @ 100% SGR), but statistically (P≤ 0.05) non significant with T 4 (CaCl 2 @ 50% SGR + biogas slurry @ 10 tˑha -1 ). T 3 (CaCl 2 @ 50 % SGR) was at par with T 6 (H 2 SO 4 @ 25% SGR + biogas slurry @ 10 tˑha -1 ), followed by T 5 (H 2 SO 4 @ 25% SGR). The minimum yield was recorded in T 1 (control). Soil analysis showed that pH s , EC e and SAR were significantly decreased in T 2, (Gypsum @ 100% SGR), followed by T 4 (CaCl 2

An effective reclamation procedure of saline sodic soils is removal of undesirable Na+ by addition of some Ca2+ source paralleled with leaching of this sodium out of root zone. Nevertheless, gypsum being a direct source of Ca2+ is relatively insoluble in water. Its solubility can be increased with addition of H2SO4. Therefore, three years (2015 to 2018) study was plan to find out the optimal and economical level of H2SO4, which can increase the solubility and reclamation efficiency of gypsum for saline sodic soil in rice wheat crop-ping rotation. Treatments included were: T1, Control, T2, gypsum @ 100% of GR, T3, gypsum @ 100% of GR+10 kg H2SO4 acre−1, T4, gypsum @ 100% of GR+50 kg H2SO4 acre−1, T5, gypsum @ 100% of GR+100 kg H2SO4 acre−1. Before start of study, soil had pHs = 8.85, ECe = 4.85 (dS m−1), SAR = 43.82 (mmol L−1)1/2, GR = 4.10 (t. acre−1), BD = 1.65 (Mg m-3), HC = 0.33 (cm hr−1). Experiment was laid out in RCBD with three replications. Sulfuric acid and gypsum were applied (once) at the start of study in the respective treatment plots. Recommended dose of fertilizers, 150-90-60 NPK kg ha−1 for rice (Shaheen Basmati) and 160-114-60 NPK kg ha−1 for wheat (Faisalabad, 2008) was applied. Yield and yield determining attributes of each crop were recorded at physical maturity. After harvest of each crop, soil samples were collected and were analyzed for ECe, pHs, SAR, bulk density and hydraulic conductivity. Pooled data analysis revealed that maximum growth and yield determining factors of rice and wheat were recorded where gypsum was applied with H2SO4 at the rate of 50 and 100 kg acre−1. Soil physical and chemical properties, i.e. pHs, ECe, SAR bulk density and hydraulic conductivity were also substantially improved with combined application of gypsum and H2SO4 at the end of study. Both levels of H2SO4 at the rate of 50 and 100 kg acre−1 with gypsum proved equally to be the best in enhancing the solubility and reclamation efficiency of gypsum and showed the statistically (p≤ 0.05) similar results in increasing the yield of rice and wheat crop and improving the soil physical and chemicals properties. Therefore, H2SO4 at the rate of 50 kg acre−1 is recommended as most economical and optimum level, which can be used with gypsum as an effective ameliorative strategy for the salt affected soils.

Selection of suitable tillage implement, as well as amendments, is very important for the reclamation of salt affected soils. For this purpose, a field study was performed using the different rates of gypsum and tillage implements for the production of sorghum and berseem fodders in salt affected field using high RSC water. Treatments including were T1: control (cultivator twice), T2: modified chisel plough (twice), T3: chisel plough (twice), T4: modified chisel plough (twice) + gypsum application @ 100% GR of soil, T5: modified chisel plough (twice) + gypsum application @ 50% GR of soil, T6: chisel plough (twice) + gypsum application @ 100% GR of soil, T7: chisel plough (twice) + gypsum application @ 50% GR of soil. A moderately salt affected field {ECe = 5.37 (d Sm−1), pHs = 9.18, SAR = 34.01 (m mol L−1)1/2 and GR 3.10 t acre−1} was selected. Field was leveled, prepared and gypsum was applied according to treatment plan, followed by leaching. Tubewell water {ECiw= 1.34 dS m−1, RSC= 8.50 me L−1 and SAR= 12.72 (mmol L−1)1/2} was used for irrigation. Gypsum was also applied before sowing of each crop on RSC basis of water. The trial was performed in the RCBD design with three replications. Pooled data of three years showed that maximum fodder yield of sorghum (38.44 t ha−1) and berseem (60.21 t ha−1) was recorded with modified chisel plough (twice) + gypsum @ 100% GR of soil. Data regarding the soil qualities revealed that soil pHs, ECe, SAR and BD decreased by 4.24, 30.72 and 31.37, respectively, while HC was increased by 130 % with use of modified chisel plough (twice) + gypsum @ 100% GR of soil, as compared to control.