Mineral Nutrition and Yield of Four Rice Genotypes in the Farmers' Fields of Salt-Affected Soils

ABSTRACT

Growing rice in saline soils with the underground, moderately saline (electrical conductivity < 2 dS/m) water in coastal environments is an attractive option for many farmers in Asian countries. This study conducted field experiments to investigate the potential of growing rice in a coastal saline environment on mineral nutrition and yield of the crop. Four rice genotypes were tested at two locations, where (1) irrigation water salinity was less than 2 dS/m (low salinity) and (2) irrigation water salinity was more than 4 dS/m (high salinity). The initial soil salinity at location (1) and (2) was 4.65 and 8.75 dS/m, respectively. At both locations, rice was grown on three farmers' fields. The soil salinity of the field at location (1) and (2) declined < 2 and < 6 dS m^{− 1}, respectively, and that level was maintained throughout the growing period. The concentration of phosphorus (P), potassium (K), sodium (Na), iron (Fe), and manganese (Mn) in rice leaves differed significantly in the two locations, but the concentrations of nitrogen (N), calcium (Ca), and magnesium (Mg) were similar. The Na/K and Fe/Mn ratios in plant tissues grown at the high-saline site were greater than those grown at the low-saline site. Salinity significantly reduced plant height and increased sterility in rice. The yields of four rice genotypes at the low-saline site ranged from 4.95 to 5.58 Mg ha^{− 1} and at the high-saline site the yield range was 4.23 to 4.60 Mg ha^{− 1}, respectively. At the low-salinity site the highest yield of 6.58 Mg ha^{− 1} was obtained with BR5777-11-2-4-1-HR2, compared with 5.20 Mg ha^{− 1} obtained with BRRI Dhan 28. At the high-saline site the yields of BR5777-11-2-4-1-HR2 and BRRI Dhan 28 were 4.53 and 4.60 Mg ha^{− 1}, respectively. Farmers' preference score for adoption was the highest for BR5777-11-2-4-1-HR2 under conditions of the low-saline site and BRRI Dhan 28 under conditions of the high-saline site, respectively.

Keywords:

• soil salinity
• water salinity
• Na/K ratio
• Na/Ca ratio
• farmers' participatory

ACKNOWLEDGMENT

We are grateful to the International Fund for Agricultural Development (IFAD) for funding this research and to Mr. M. N. Bari and Mrs. Sanjita Parveen Ritu for cooperation in the field experiment.

Notes

¹ Preference score: 1 = lowest, 10 = highest.