ST Zodape’s research while affiliated with Central Salt and Marine Chemicals Research Institute and other places

Strategies for sustainably increasing sugarcane productivity without any negative implications to the environment are challenging. In the present investigation, field trials were conducted to demonstrate the potential of an agro-technique involving foliar applications of Kappaphycus alvarezii seaweed based biostimulant in combination with recommended rate of synthetic fertilizers (RRF) for sustainably enhancing sugarcane production and mitigating environmental impacts. Kappaphycus seaweed extract (KSWE) applied at 5% concentration enhanced cane productivity by 12.5 and 8%, respectively, in plant and ratoon crops. Interestingly, the treatment involving 6.25% KSWE +50% RRF showed yield parity (p < 0.05) with control (water+100% RRF) in ratoon while there was 7.9% reduction over control in plant crop with a concomitant savings of 50% RRF. These results revealed that KSWE application in addition to recommended rate of fertilizer application, can reduce gap between potential and real yield which otherwise requires application of incremental inputs in the form of synthetic fertilizers to obtain similar yields. The findings confirmed our hypothesis that the use of KSWE not only results in hypothetical savings in the incremental application of synthetic fertilizers but also can be used for achieving target yields sustainably. The sugar yield too was enhanced thus increasing the returns on investment. The technique is practically feasibility and scalability. The potential of the KSWE in lowering GHGs is manifested by the way of saving at least 260 kg CO2 equivalents (Mg cane production)⁻¹ ha⁻¹ when applied at 5% concentration. This would translate in to savings of ca. 9.3 million Mg of CO2 equivalents if one assumes employing KSWE for at least 10% of the total cane production in India for the year 2015–16. Therefore, the present study advocates a paradigm shift in policy to encourage use of biostimulants in the context of mitigating adverse effects of global climate change and expecting better returns from sugarcane cultivation.

Enhancing productivity through integrated nutrient management is pertinent to sustainable intensification of agricultural ecosystems. Field experiments were conducted during 2012 and 2013 in Eastern Himalayas with extracts from Kappaphycus alvarezii (K sap) and Gracilaria edulis (G sap) to assess growth, productivity and quality enhancement of rice (Oryza sativa). A Petri dish experiment was also conducted to assess the efficacy of saps in improving germination percentage and seedling vigour of rice seedlings. Field experiment included foliar spray of K and G saps (2.5, 5, 10 and 15% concentrations) with 100% recommended dose of fertilizers (RDF) along with water spray + 100% RDF (control). The rice seeds soaked with lower concentrations (2.5 and 5%) of K and G saps recorded higher germination percentage, root and shoot length and seedling vigour index as compared to water soaking. Whilst soaking in higher concentrations (7.5% and above) reduced the germination percentage and seedling vigour index. Foliar spray of K or G sap at 5% and above concentrations + 100% RDF significantly increased plant height, dry matter accumulation, chlorophyll index, crop growth rate, yield attributes and yield of rice (5.4 to 18.4% higher) as compared to control. Application of K or G sap at 10% concentrations + 100% RDF also increased micro-nutrient (Fe, Cu, Zn and Mn) and protein concentration in rice grains. Thus, foliar application of 10% K or G sap along with 100% RDF is a recommendable option for improving yield and quality of rice and sustaining soil fertility in eastern Himalayas and similar agroecosystems elsewhere.

A field experiment was conducted during the summer season of 2013 at Central Potato Research Station, Shillong, Meghalayato study the effect of sea weed saps on growth and productivity of potato in the North Eastern hill region of India.The trial was laid out in randomized block design, replicated thrice, with 10 treatments. The number of shoot per plant was found to be non-significant and vary from 2.8 to 3.0. The maximum plant at harvest was recorded under application 7.5 Kappaphycus Spray + 100% RDF while lowest under 6.25% + 50% RDF.Maximum small size tuber was found with an application of 10 % Gracilaria spray + RDF which was at par with 2.5 % Kappaphycus spray + RDF and 7.5 % Gracilariaspray + RDF but significantly superior to other treatment. However, the highest medium size tube of potato was noticed under 6.25% Kappaphycus spray along with 50% recommended dose of fertilizer. Highest large size tuber was recorded with an application of 5% Kappaphycusspray + RDF followed by 2.5% Kappaphycus spray along with RDF as well as 7.5 % Gracilaria spray + RDF which was at par, but significantly superior to rest of treatment. Application of 2.5% Kappaphycus spray + 100% RDF recorded the highest productivity of potato (27.1 t/ha) followedby 100% RDF + Kappaphycus spray @ 5.0% (26.6 t/ha) which were at par with each other but significantly superior to the rest of treatments.Based on the economic yield of potato, it may be concluded that the application of 2.5 % Kappaphycus spray + 100% RDF was found to be more profitable under rainfed condition of Meghalaya

A field experiment was conducted during winter season of 2012-13 in sandy loam soil at Central Potato Research Station, Patna to study the effects of seaweed saps on growth, yield and nutrient uptake of Potato. The foliar spray was applied at 45, 60 and 75 days after planting at different concentrations (0, 2.5, 5.0, 7.5 and 10 % v/v) of seaweed extracts namely Kappaphycus( K Sap) and Gracilaria (G Sap). Foliar applications of seaweed sap significantly enhanced large and medium grade as well as total tuber yield. Increment in total tuber yield of potato with application of 7.5% K sap + recommended dose of fertilizer (RDF), 5% G sap + RDF, and 10% G sap + RDF) over control were in tune of 3.95 t ha-1 ,4.88 and 4.07 t ha-1 respectively. Applications of 7.5 % K sap+ RDFand 5% G sap + RDF resulted in increase by 15.8 and 34.9% in large grade tuber yield and 11.5% and 22.5% in medium grade tuber yield, respectively compared to control. Improved nutrient uptake (NPK) was also observed with seaweed extract.

A field trial was conducted to evaluate the efficacy of Kappaphycus and Gracilaria based seaweed extracts (SWEs) to enhance the yield of rice in red and lateritic soils and also simultaneously assess the sustainability of the use of SWEs through life cycle assessment. A total of thirteen treatments involving combinations of recommended rate of fertilizers (RRF) 80: 40: 40 N: P2O5: K2O kg ha⁻¹ and SWEs applied at concentrations (2.5, 5, 7.5, 10 and 15%) were tested along with a suitable control (water spray + RRF) in a randomized block design. The efficacy of SWEs at 7.5% was also tested with lower dose of RRF (50% RRF). The SWEs were foliar applied 25, 50, and 70 d after transplanting of rice. Life cycle impact assessment (LCIA) for the production of fertilizers and SWEs required for 1ha of rice cultivation was carried out using ReCiPe Midpoint method and were expressed as impacts t⁻¹ of rice production. Combined analysis of data of the experiment revealed that SWEs from Kappaphycus (KSWE) and Gracilaria (GSWE) when applied at 15% concentration significantly increased the grain yield of rice by 29% and 28%, respectively, over control; however, SWEs at 10% gave more net benefit per unit investment compared to the control. Notably, the grain yield in the treatments involving combination of SWEs with 50% RRF was statistically at par with control. LCIA revealed that in comparison to the control, maximum reductions of 11.4% and 14.8% in climate change (CC) impact category t⁻¹ of rice were obtained in treatments involving combination of RRF with 15% KSWE and 10% GSWE, respectively. Interestingly, treatments involving 50% RRF + SWEs brought about at least 43% reduction in CC impact t⁻¹ of rice, which amounts to savings of about 35 kg CO2-equivalents t⁻¹ of rice. Similarly, reductions were also observed for other impact categories. SWEs offer great promise in global perspective towards mitigating climate change as well as other environmental impacts and sustainably increasing rice yield.