Investment decision model for drip irrigation system

Drip irrigation is becoming popular in India although the decision to shift to drip irrigation from surface irrigation is not backed up by solid economic factors. It is not that the factors do not justify the shift, but that insufficient study has been done to document the conditions under which a change is justified. The investment decision for shifting to drip irrigation will depend upon many factors; including cost of cultivation, productivity, yield gain factor, cost of produce, electricity charges, depth of groundwater and irrigation requirement. These parameters vary from crop to crop, place to place, size of plot, and farmer to farmer. Therefore a sweeping recommendation suitable for all conditions cannot be made. In view of this, a software program has been developed for estimating the threshold economic value of the investment cost of drip irrigation. In addition to the threshold value of investment cost, the software provides information on energy consumption and net return. The software can be used both for annual crops such as sugarcane or seasonal crops such as vegetable rotations (winter–summer). To demonstrate the interdependence of various input parameters, an analysis has been made using local data in this software. The analysis has provided the relationship between the investment cost and the yield gain factor, the returns from the crop, as well as the savings in energy and the size of the prime mover with regard to the size of the farm.     

Modeling rice seedling emergence and growth under tillage and residue management in a rice–wheat system on a Vertisol in Central India

Tillage and residue management practices are known to affect seedling emergence and growth. However, information on direct seeded rice (Oryza sativa L.) in rice–wheat (Triticum spp.) cropping system is lacking. Thus a study was undertaken under different tillage (conventional and zero tillage) and residue (residue-retained and removed) management options on rice seedling emergence and growth in rice–wheat system on a Vertisol of Central India. Seedling emergence was greater in residue removed plots compared to residue-retained one. Prediction of rice seedling emergence with the France and Thornley [Mathematical Models in Agriculture and Related Sciences, Butterworths, London, 1984] model and growth by the Logistic and Gompertz model, and Monomolecular model were also attempted. Emergence indicators showed that seedling emergence of rice was favored more by conventional tillage than zero tillage in wheat. Of the three models tested, the Gompertz model gave the best fit. The effect of tillage and residue of wheat on the estimated parameters of the models were also studied.     

Decomposition of biodegradable packing materials jute, Biopol, BAK and their composites in soil

We investigated the effects of the biodegradable polymers jute, Biopol and BAK 2195 and their composites on the mineralisation activity and biomass of microorganisms in soil and on the fungal component of the microbial community. Two different pre-treatments of jute were used to produce the composites, treatment of the fibres with sodium hydroxide (SH-jute) and co-polymerisation with acrylonitrile (AN-jute). All products tested were highly degradable, as indicated by the increase in CO₂ evolution after amendment. The additional amount of CO₂-C evolved after polymer incorporation into the soil corresponded to between 21% and 34% of the added C after 85 days incubation at 25°C. The extra CO₂-C evolved decreased in the order BAK > jute > Biopol. Composites of AN-jute were less mineralisable than those of SH-jute. Degradation of jute is characterised by a rapid increase, then a slow decline of microbial respiratory activity. In contrast, in the Biopol treatments, and especially in the BAK treatments, maximum CO₂ evolution rates occurred considerably later, indicating that the soil microorganisms needed some time to colonise the polymer particles. All polymers and composites tested increased the soil microbial biomass in the order jute h Biopol < BAK. The net increase in microbial biomass C was 3% of the added polymer C in the jute treatment, an average of 4% in the three Biopol treatments, and 7% in the three BAK treatments. The content of ergosterol, an indicator for fungal biomass, was also increased by all amendments, but the effect on ergosterol content was much more pronounced than on microbial biomass C.     

Glacial refugia: hotspots but not melting pots of genetic diversity

Glacial refuge areas are expected to harbor a large fraction of the intraspecific biodiversity of the temperate biota. To test this hypothesis, we studied chloroplast DNA variation in 22 widespread European trees and shrubs sampled in the same forests. Most species had genetically divergent populations in Mediterranean regions, especially those with low seed dispersal abilities. However, the genetically most diverse populations were not located in the south but at intermediate latitudes, a likely consequence of the admixture of divergent lineages colonizing the continent from separate refugia.     

Ethno-medico-biology of Bhadrak district, Odisha, India

We carried out an ethno-medico-biological investigation in the interior of Bhadrak district, Odisha, India to explore the therapeutic use of traditional plants/animals by local inhabitants. The villagers and rural people used plant and animal species as medicine. We recorded therapeutic use of 18 plant species of 13 families and 12 animal species of seven taxonomic categories. Different plant/animal parts like bark, leaf, flower, seed, stem, root, whole plant, oil, blood, milk, urine and flesh were reported as used in raw or cooked form against 17 specific diseases. Prominent diseases treated by plant/animal remedies were asthma, cardiovascular ailments, diabetes, epilepsy, jaundice, malaria, skin disorder and rheumatism. This study provides a better database for future studies.     

Water budgeting in a carp‐prawn polyculture system: impacts on production performance,water productivity and sediment stack

This study was designed to quantify the total water requirement and consumptive water use in carp‐prawn polyculture system under different water management protocols, using water balance model. Under different water management protocols, treatment‐wise estimated total water use, TWU (×10⁴, m³) was 3.7, 4.6 and 3.9, while the computed consumptive water use index, CWUI (m³ kg^?1 biomass) was 6.62, 9.31 and 7.08, in T₁ (no water exchange), T₂ (periodic water exchange) and T₃ (regulated water exchange) respectively. Significantly higher yield (P < 0.05) in both T₂ and T₃ over T₁, was probably due to water exchange that improved the rearing environment. Although intensity of water exchange was more in T₂, significant variation (P < 0.05) in overall growth and yield was not recorded between T₂ and T₃. Treatment‐wise sediment load ranged between 54.6 and 71.3 m³ t^?1 biomasses. Higher sediment load was recorded at lower intensity of water exchange as well as with higher apparent feed conversion ratio. Higher net total water productivity, net consumptive water productivity and OV‐CC ratio in T₃ infers that regulated water exchange has a distinct edge over the no water exchange protocol. Restricted water use instead of regular/excess water exchange not only improves the production performance and water productivity, but also helps in lessening the operational pumping cost.     

Yield characteristics and morphometric relationships of giant freshwater prawn,Macrobrachium rosenbergii (de Man, 1879)

Meat yield of 233 individuals of giant freshwater prawn, Macrobrachium rosenbergii (de Man, 1879), and their morphometric relationships were examined. Morphometric parameters of different length and weight measurements were recorded for both the sexes separately and subjected to analysis. The meat yield of prawns was size and sex dependent with females showing significantly greater (P < 0.05) tail meat yield than males. The tail meat as a body weight percentage ranges from 26.12 to 40.75 and 32.97 to 42.11 in males and females, respectively. Much of the differences in yield are related to the size and weight of the head and claws. The head weight of males was observed to be higher compared to females in all the size classes. Regression slopes of total length versus body weight and total length versus head weight were significantly higher than critical isometric value indicating high positive allometric growth in both the sexes, with males showing significantly higher (P < 0.05) slope than females. The relationship parameters of total length versus tail weight and total length versus tail meat showed a positive allometric growth in females, whereas it is isometry and negative allometry in males. The morphometric relationship of tail length versus all weight measurements showed positive allometry and negative allometry in females and males, respectively.     

The immune response in rohu,Labeo rohita (Actinopterygii: Cyprinidae) to Argulus siamensis (Branchiura: Argulidae) infection: kinetics of immune gene expression and innate immune response

Argulus siamensis is a major pathogen in freshwater aquaculture. The immune responses of Indian major carp, Labeo rohita to experimental infection of A. siamensis was evaluated by quantitation of immune‐relevant gene expression in head kidney and skin, and serum innate immune parameters through the course of infection. In skin of infected fish, antioxidant genes like natural killer cell enhancing factor (NKEF‐B) and superoxide dismutase (MnSOD) were significantly up‐regulated in addition to lysozyme G and β₂ microglobulin (β₂M). Both tumour necrosis factor α (TNFα) and toll‐like receptor 22 (TLR22) genes were significantly down‐regulated in skin during early phases of the infection. Most of the genes exhibited significant down‐regulation in head kidney; immunoglobulin (IgM) and β₂M genes being the exceptions which were significantly up‐regulated at 12 h and 3 days post infection. Most of the innate immune parameters like serum complement activity and ceruloplasmin levels showed significant reduction in infected fish. The observed results are indicative of A. siamensis modulating the immune response of rohu by down‐regulation of many immune factors which may explain the susceptibility of rohu to A. siamensis infection. The interaction of this parasite with the host need to be further explored to understand its pathogenesis.     

Survival,male morphotypes,female and male proportion,female reproductive status and tag loss in crosses among three populations of freshwater prawn Macrobrachium rosenbergii (de Man) in India

The present study examined the variation in survival, proportion of male morphotypes, female and male proportion, female reproductive status and tag losses in nine crosses from a complete (3 × 3) diallel mating of three populations of Macrobrachium rosenbergii in India. The populations originated from Gujarat (north‐west), Kerala (south‐west) and Odisha (east), representing different agro‐ecological regions in India. Progeny from 60 families (4773 juveniles) were individually tagged and reared for 16–17 weeks in earthen ponds. Binary logistic regression was used to analyse the data. Survival rate was greatest (0.88) for Kerala × Odisha (KO; the first letter represents the sire), whereas it was lowest (0.75) for both Kerala × Kerala (KK) and Gujarat × Kerala (GK). Significantly greater proportions of large male morphotypes were observed in KK cross and in combinations involving Kerala population. The highest proportion of immature females, as well as of non‐berried females, was observed in the Odisha × Odisha (OO) cross. Tag loss was greatest for KK (0.35) and lowest for GG (0.19). We found significant variations among crosses for all studied traits suggesting the possibility of including them in genetic improvement programmes of this species.