ABSTRACT

It is well known that soil is the basic media for agriculture, on which crop yield is mostly depended; hence the study analyzed nine important soil nutrients collected from 32 specified locations in Barishal and Patuakhali districts (16 from Barishal and 16 from patuakhali ) during the period of 2017 to 2019. The soil nutrients were measured in Khulna University Environmental Science Discipline Laboratory, Khulna. The pH values ranged 6.7 to 7.8 in Barishal district. In Patuakhali district, pH ranged 5.8-7.3, which proved the quite acidity in soil. The detected EC values in Barishal were below 1 in most of the cases. On the other hand, the soil EC measured as 0.06-7.1 ds/m in Patuakhali district. About half of the samples confirmed the desired OM with the values 0.91-2.53% OM in Barishal district. Other remaining samples did not ensure the desired value fallen up to 0.91%. The values of OM were higher OM in Patuakhali district ranged as 0.91-2.53%. The total N content in the soil was generally very low to low, ranging from 0.053-0.168 and 0.053-0.129% in Barishal and Patuakhali districts, respectively. In surface soil, the available phosphorus (P) content ranged from (5.75 to 11 µg/g) with the mean values 8.879 µg/g in Barishal district, while the average P value was 7,400 µg/g varied as 4.29-13.16 µg/g in Patuakhali district. The K values obtained confirmed the sufficient K values both in Barishal and Patuakhali districts compared to std. values for FRG (2012). The study detected the amount of S as 11.01-94.98 µg/g in Barishal district, but 12.44 -172.39 µg/g in Patuakhali. The extreme level of S was measured due to frequent handling S containing chemicals/materials in the rural coastal agricultural fields of Bangladesh. The analyzed Zn amount recorded as 0.31-0.66 µg/g in Barishal districts, which confirmed the lower Zn, whereas, optimum (0.10-1.65 µg/g) in Patuakhali district. The detected B status confirmed the enough B contents in Patuakahli soil.

Key words: Salinity, chemical properties, central-coast.

Introduction

Various types of environmental issues and problems are hindering the development of coastal livelihood of Bangladesh. Salinity is one of them, which is expected to aggravate by climate change and sea level rise and eventually affect food production. Bangladesh has 147,570 km2 land area that includes 710 km coastal line along the Bay of Bengal (BBS, 2003). In Bangladesh about 0.883 million hectares of the arable lands, which constitutes about 52.8 percent of the net cultivable area in 64 Upazilas of 13 districts, are affected by varying degrees of soil salinity (Karim et al., 1990). A recent study indicates that the salinity affected area has increased from 8,330 km2 in 1973 to 10,560 km2 in 2009 (SRDI, 2010). Tidal flooding occurs during wet season (June-October), direct inundation by saline water and upward on lateral movement of saline ground water during the dry season (November-May) (Haque, 2006). In addition, cyclone and tidal surge is accelerating this problem (Abedin, 2010). In the coastal areas of Bangladesh, saline water is used for irrigation which reduces the growth of most agricultural crops (Murtaza et al., 2006). Salinity is causing decline in soil productivity and crop yield which results in severe degradation of bio-environment and ecology as well as responsible for low cropping intensity in coastal area (Rahman and Ahsan, 2001). Rice (Oryza sativa L. spp. indica) is one of the five main carbohydrate crops responsible for feeding the world’s population including Asian countries and more than 3 billion people which comprises 50%-80% of their daily calorie intake from rice (Khush, 2005). Rice has previously been reported as salt susceptible in both seedling (Munns and Tester, 2008), and reproductive stages (Moradi and Ismail, 2007) leading to a reduction of more than 50% in yield when exposed to 6.65 dSm-1 EC (Zeng and Shannon, 2000). Ali 78