Fertility status of mulberry (morus alba l.) garden soils of bivoltine sericultural areas and their impact on cocoon production in Karnataka

It is a well-known fact that availability of organic manures are very much limited in the present day agriculture but demand for organic and inorganic nutrient supply to the soils ever growing due to intensive cropping systems. Therefore, the application of nutrients needs to be increased to keep the soil fertile and to make agriculture sustainable, but the cost of inorganic fertilizers escalating day by day making any farming is expensive. Therefore, it is essential to provide soil analysis based prescription for suitable amelioration of mulberry gardens for enhanced quality leaf and cocoon production thereby minimizing the cost of cultivation. In the present study a total of 2067 composite soil samples were collected from the traditional bivoltine sericultural areas spread over in 13 districts of Karnataka and subjected for their chemical analysis to determine the soil fertility status viz. soil type, reaction, salinity and nutrient status. Out of the soils analysed it was observed that 52% of the soils were recorded as loamy, 28% red, 12% black and 8% were lateritic indicating that large number of soils are most suitable for mulberry cultivation. In regard to the soil reaction (pH), 59% of the soils showed desirable pH (6.5-7.5), 18% low (<6.5) and 23% soils were recorded with higher pH (>7.5). Soil salinity (EC) was recorded ideal in 99% soils indicating that most of the soils bearing ideal salinity for mulberry growth (<1.0 dS/m). Organic carbon (OC) was recorded low (<0.65%) in higher number of soils (76%), desirable range (0.65-1.0%) in 23%, however negligible number of soils showed higher OC content (>1.0%). Organic carbon is considered as the fertility indicator of any soil and the same was found low in mulberry soils. Available nitrogen (N) and phosphorous (P) were recorded low (<250kg/ha; <15kg/ha) in 98% and 45% soils, respectively, whereas P was in medium level (15-25kg/ha) in 23% and higher (>25kg/ha) in 32% soils. Desirable range (120-240kg/ha) of available potassium (K) was recorded in 49% soils, low (<120kg/ha) in 20% and 31% soils are in high (>240kg/ha). Available sulphur (S) was recorded high (>15ppm) in 54% soils followed by 41% desired level (10-15ppm), whereas 5% soils shown low level (<10). In case of available boron (B) it was noticed that 44% soils recorded as low (<0.5ppm), 43% are desired level (0.5-1.0), whereas 13% soils exhibited high content of B (>1.0ppm).