Setia R.,University of Adelaide |
Marschner P.,University of Adelaide |
Baldock J.,University of Adelaide |
Baldock J.,CSIRO |
And 2 more authors.
Soil Biology and Biochemistry | Year: 2011
Net carbon dioxide (CO2) emission from soils is controlled by the input rate of organic material and the rate of decomposition which in turn are affected by temperature, moisture and soil factors. While the relationships between CO2 emission and soil factors are well-studied in non-salt-affected soils, little is known about soil properties controlling CO2 emission from salt-affected soils. To close this knowledge gap, non-salt-affected and salt-affected soils (0-0.30 m) were collected from two agricultural regions: in India (irrigation induced salinity) and in Australia (salinity associated with ground water or non-ground water associated salinity). A subset (50 Indian and 70 Australian soils) covering the range of electrical conductivity (EC) and sodium adsorption ratio (SAR) in each region was used in a laboratory incubation experiment. The soils were left unamended or amended with mature wheat residues (2% w/w) and CO2 release was measured over 120 days at constant temperature and soil water content. Residues were added to overcome carbon limitation for soil respiration. For the unamended soils, separation in multidimensional scaling plots was a function of differences in soil texture (clay, sand), SOC pools (particulate organic carbon (POC) and humus-C) and also EC. Cumulative CO2-C emission from unamended and amended soils was related to soil properties by stepwise regression models. Cumulative CO2-C emission was negatively correlated with EC in saline soils (R2 = 0.50, p < 0.05) from both regions. In the unamended non-salt-affected soils, cumulative CO2-C emission was significantly positively related to the content of POC for the Indian soils and negatively related to clay content for the Australian soils. In the wheat residue amended soils, cumulative CO2-C emission had positive relationship with POC and humus-C but a negative correlation with EC for both Indian and Australian soils. SAR was negatively related (β = -0.66, p < 0.05) with cumulative CO2-C emission only for the unamended saline-sodic soils of Australia. Cumulative CO2-C emission was significantly negatively correlated with bulk density in amended soils from both regions. The study showed that in salt-affected soils, EC was the main factor influencing for soil respiration but the content of POC, humus-C and clay were also influential with the magnitude of influence depending on whether the soils were salt affected or not. © 2010 Elsevier Ltd.
Forouzangohar M.,University of Melbourne |
Setia R.,Punjab Remote Sensing Center |
Wallace D.D.,Agriculture Productivity Group |
Nitschke C.R.,University of Melbourne |
Bennett L.T.,University of Melbourne
Climate Research | Year: 2016
Research on the impacts of climate change on soil organic carbon (SOC) stocks has focused on the effects of changes in average climate, but the potential effects of increased climate variability, including more frequent extreme events, remain under-examined. In this study, set in a semiarid agricultural landscape in southeastern Australia, we used the Rothamsted carbon (RothC) model to isolate the effects of interannual rainfall variability on SOC stocks over a 50 yr period. We modelled SOC trends in response to 3 scenarios that had the same 50 yr average climate but different interannual rainfall distributions: non-changing average climate, historic variability (H), and increased variability due to more frequent extreme rainfall years (XH). Relative to the non-changing average climate, RothC simulations predicted net decreases in mean SOC stocks to 50 yr of 11% under the H scenario and 13% under the XH scenario. These decreases were the result of predicted SOC decreases (and increased CO2 emissions) in extreme wet years (ca. 0.26 Mg ha-1 yr-1) that were not counterbalanced by SOC increases in extreme dry years (ca. 0.11 Mg ha-1 yr-1). No significant difference in mean SOC stocks at 50 yr between the H and XH scenarios was likely due to an increase in both extreme wet and counterbalancing extreme dry years in the latter. Strong negative correlations were found between annual changes in SOC stocks and rainfall. Our modelled predictions indicate the potential for extreme rainfall years to influence SOC gains and losses in semiarid environments and highlight the importance of maintaining plant inputs in these environments, particularly during extreme wet years. © Inter-Research 2016.
Dhawan A.K.,Punjab Agricultural University |
Mukherjee J.,Punjab Agricultural University |
Kang G.S.,Punjab Agricultural University |
Singh H.,Punjab Remote Sensing Center
Indian Journal of Ecology | Year: 2014
In this study the fertilization unsuitability index (FUI) has been proposed for estimating soil contamination and nutrient imbalance resulting from fertilizer application at farm source. The fertilizer use data was collected directly from the selected farmers in the study area and interpolated environmental risk resulting from over fertilization was represented in spatial format using Arc GIS software. The results reported that urea was applied more than double the amount recommended for cotton and wheat cultivation where as the diammonium phosphate was applied at recommended levels in wheat and 50% above recommended dose in cotton in majority of villages in the study area. The average value of FUI was higher in cotton (527.205) in comparison to wheat (491.35) when nitrogen and phosphorus requirement of crops was met by application of urea and diammonium phosphate. Whereas the maximum FUI was reported in Muktsar district (544.52) for fertilization in wheat crop and it was reported to be 536.82 in cotton fertilization. The average soil contamination (SC) risk was higher in cotton fertilization (2.79) than in wheat fertilization (2.47) and the maximum value was reported in Muktsar district for cotton fertilization (3.11). The wheat fertilization practice in the study area threats only nitrate pollution whereas the fertilization in cotton has associated risks of both nitrate and phosphate pollution in the study area.
Sumbria D.,Guru Angad Dev Veterinary and Animal Sciences University |
Singla L.D.,Guru Angad Dev Veterinary and Animal Sciences University |
Kumar S.,National Research Center on Equines |
Sharma A.,Guru Angad Dev Veterinary and Animal Sciences University |
And 2 more authors.
Acta Tropica | Year: 2016
Equine piroplasmosis is a febrile, tick-borne disease of equids predominately caused by obligatory intra-erythrocytic protozoa Theileria equi in the Indian sub-continent. A cross-sectional study was carried out on 464 equids (426 horses and 38 donkeys/mules) in Punjab, India to assess the level of exposure to equine piroplasmosis by 18S rRNA gene nested polymerase chain reaction (nPCR) and equine merozoite antigen-2 (EMA2) indirect-ELISA (enzyme linked immunosorbent assay), to investigate risk factors and haemato-biochemical alterations associated with the infection. The endemicity of the disease was confirmed by positive PCR amplification in 21.77% and positive antibody titers in 49.78% equid samples. There was a fair agreement between these two diagnostic techniques (Kappa coefficient=0.326). The spatial distribution analysis revealed an increasing trend of T. equi prevalence from north-eastern to south-western region of Punjab by both the techniques correspondingly, which proffered a direct relation with temperature and inverse with humidity variables. The relatively prominent risk factor associated with sero-positivity was the presence of other domestic animals in the herd, while the propensity of finding a positive PCR amplification was higher in donkeys/mules, animal kept at unorganised farm or those used for commercial purposes as compared to their counterparts. There was a significant increase in globulins, gamma glutamyl-transferase, total bilirubin, direct bilirubin, indirect bilirubin, glucose levels and decrease in total erythrocyte count, haemoglobin, packed cell volume by animals, which were revealed positive by nPCR (may or may not positive by indirect-ELISA) and increase in creatinine, total bilirubin, direct bilirubin, glucose and decrease in total erythrocytes count by animals, which were revealed positive by indirect-ELISA (alone). To our knowledge, this study, for the first time, brings out a comprehensive report on the status on spatial distribution of T. equi in Punjab (India) state, thoroughly investigated by molecular and serological techniques, evaluating various environmental and demographic risk factors along with the haemato-biochemical alterations in the exposed animals. © 2015 Elsevier B.V.
Buttar G.S.,Punjab Agricultural University |
Jalota S.K.,Punjab Agricultural University |
Sood A.,Punjab Agricultural University |
Sood A.,Punjab Remote Sensing Center |
Bhushan B.,Punjab Agricultural University
Indian Journal of Agricultural Sciences | Year: 2012
Cotton cultivation in semi-arid region of Indian Punjab is considered as most risky crop as its yield is very sensitive to weather parameters like rain and temperature. In future due to global warming increase in the temperature is expected, which is most likely to influence the growth and yield of this fiber crop like other cereal crops. Studies on the effect of temperature on the growth and seed yield of Bt cotton in this region are lacking. The present 2-year field and 15-year simulation studies concern to simulate the effect of temperature on duration of pheno-phases and seed yield of Bt cotton hybrid RCH 134 and also on crop water productivity. Simulations were run for 15 years (1991-2005) using the already customized CropSyst model. The simulated results indicated that with increase in temperature from 28 to 32oC, cotton seed yield was reduced to half (from 4 700 to 2 300 kg/ha) following a linear relation with high coefficient of determination (0.97), and the reduction was more with increased temperature during sowing to flowering stage than other pheno-phases. Total evapo-transpiration (ET) during crop period and crop water productivity was also decreased with increased temperature. Relationship of cotton seed yield was linear with ET and quadratic with total water supply (rain +irrigation). Real crop water productivity (yield/ET) and apparent crop water productivity (yield/irrigation water) were 0.362+0.129 and 0.485+0.120 kg/m 3, respectively.