Modeling Sunflower Productivity and Profitability in Relation to Adequate and Limited Sulphur Availability under Semiarid Irrigated Conditions

Inadequate and/or imbalanced fertilization has been identified as one of the critical bottlenecks holding oilseeds production and productivity. Sustainable production requires efficient use of inputs maintaining optimum yield and high quality product. The present study aims at defining the quantitative relationship between the fertilizer S applied and the sunflower yield obtained using a polynomial function. The analysis was done to allocate the S fertilizer for maximization of net profit over fertilizer cost depending on the availability of the fertilizer. The results indicated that the cost effective economically optimum dose of sulphur for sunflower cultivation was found to be 36.70 kg S/ha under its full availability. The expected sunflower yield at this dose was worked out to be 2.619 t/ha. However, it is advisable to uniformly distribute the fertilizer to all over the cultivable area under its limited availability for exploiting the desired yield potential and maximum net monetary returns

Clostridia Initiate Heavy Metal Bioremoval in Mixed Sulfidogenic Cultures

Sulfate reducing bacteria (SRB) are widely used for attenuating heavy metal pollution by means of sulfide generation. Due to their low metal tolerance, several SRB species depend on associated bacteria in mixed cultures to cope with metal-induced stress. Yet the identity of the SRB protecting bacteria is largely unknown. We aimed to identify these associated bacteria and their potential role in two highly metal-resistant mixed SRB cultures by comparing bacterial community composition and SRB activity between these cultures and two sensitive ones. The SRB composition in the resistant and sensitive consortia was similar. However, whereas the SRB in the sensitive cultures were strongly inhibited by a mixture of copper, zinc, and iron, no influence of these metals was detected on SRB growth and activity in the resistant cultures. In the latter, a Gram-positive population mostly assigned to Clostridium spp.initiated heavy metal bioremoval based on sulfide generation from components of the medium (mainly sulfite) but not from sulfate. After metal levels were lowered by the Clostridium spp. populations, SRB started sulfate reduction and raised the pH of the medium. The combination of sulfite reducing Clostridium spp. with SRB may improve green technologies for removal of heavy metals

Modeling sunflower productivity and profitability in relation to adequate and limited sulfur availability under semiarid irrigated conditions.

Inadequate and/or imbalanced fertilization has been identified as one of the critical bottlenecks holding oilseeds production and productivity. Sustainable production requires efficient use of inputs maintaining optimum yield and high quality product. The present study aims at defining the quantitative relationship between the fertilizer S applied and the sunflower yield obtained using a polynomial function. The analysis was done to allocate the S fertilizer for maximization of net profit over fertilizer cost depending on the availability of the fertilizer. The results indicated that the cost effective economically optimum dose of sulphur for sunflower cultivation was found to be 36.70 kg S/ha under its full availability. The expected sunflower yield at this dose was worked out to be 2.619 t/ha. However, it is advisable to uniformly distribute the fertilizer to all over the cultivable area under its limited availability for exploiting the desired yield potential and maximum net monetary returns