Evaluating partial root-zone irrigation and mulching in okra (Abelmoschus esculentus L.) under a sub-humid tropical climate

The field experiments were conducted to compare the alternate partial root-zone irrigation (APRI) with and without black plastic mulch (BPM) with full root-zone irrigation (FRI) in furrow-irrigated okra (Abelmoschus esculentus L. Moench) at Bhubaneswar, India. APRI means that one of the two neighbouring furrows was alternately irrigated during consecutive watering. FRI was the conventional method where every furrow was irrigated during each watering. The used irrigation levels were 25% available soil moisture depletion (ASMD), 50% ASMD, and 75% ASMD. The plant growth and yield parameters were observed to be significantly (p 0.05) higher with frequent irrigation (at 25% ASMD) under all irrigation strategies. However, APRI + BPM produced the maximum plant growth and yield using 22% and 56% less water over APRI without BPM and FRI, respectively. The highest pod yield (10025 kg ha-1) was produced under APRI at 25% ASMD + BPM, which was statistically at par with the pod yield under APRI at 50% ASMD + BPM. Irrigation water use efficiency (IWUE), which indicates the pod yield per unit quantity of irrigation water, was estimated to be highest (12.3 kg m-3) under APRI at 50% ASMD + BPM, followed by APRI at 25% ASMD + BPM. Moreover, the treatment APRI at 50% ASMD + BPM was found economically superior to other treatments, generating more net return (US $ 952 ha-1) with higher benefit–cost ratio (1.70)

Not Available

Not AvailableUse of rainfall anomaly based Standardized Precipitation Index (SPI) and satellite-derived Vegetation Condition Index (VCI) are becoming common to assess the impacts of drought on crops. This study analysed spatio-temporal intra-seasonal and inter-seasonal relationships for 24 years between rainfall and NDVI and between SPI and VCI to understand crop response to water availability in the Rajasthan State, India. To separate the effect of weather and technology on crop growth over time, a modification in VCI was proposed and called “Trend Adjusted VCI” (VCITadj). The VCITadj was computed for early, mid, late and whole crop seasons by deriving pixel wise crop phenology metrics from NDVI profile. Significant linear relationships were found between NDVI and rainfall but phase of crop season affected the strength of this relationship. The SPI and VCITadj were linearly related in all the four seasons, the strength of relationship improved with the progress of crop season and these relationships were stronger than between rainfall and NDVI. These relationships broke down in irrigated croplands. As a result, the anomaly indices of SPI and VCITadj and their intra-seasonal relationships can be used to study the response of crops to water availability for early detection and better prognosis of agricultural drought.IARI In-house Project Grant IARI:NRM:14:(04

Not Available

Not AvailableA study was conducted to analyse the frequency and temporal trend of standardized precipitation index (SPI) at IARI, New Delhi station during early kharif (June-August), mid kharif (August and September), late kharif (September and October) and whole kharif (June-October) from 1951 to 2009. SPI was calculated at four time scales, i. e., trimonthly, bimonthly AS, bimonthly SO, and pentamonthly corresponding to early, mid, late and whole kharif seasons, respectively. There were five years with moderate drought (1979, 1986, 1987, 1997, 2009) and three years with extreme drought (1951, 1989, 2002) during the early kharif. During the mid kharif, there were seven years with moderate drought (1951, 1953, 1954, 1986, 1989, 1999, 2006), two years with severe drought (1974, 1981) and one year with extreme drought (1979). During the late kharif, four years experienced moderate drought (1974, 1979, 1982, 2002), three years severe drought (1953, 1987, 1994), and two years extreme drought (1952, 1968). The whole kharif season experienced three moderate drought years (1952, 1979, 1997), three severe drought years (1986, 1987, 2002), and two extreme drought years (1951, 1989). There was no temporal trend in the rainfall amount or its distribution at the last 59 years at the IARI New Delhi station. It can be concluded that meteorological drought has nearly the same frequency for early, mid, late and whole kharif seasons in this station. Results suggest that rainfall variability and magnitude has not changed significantly at Delhi in the recent past though Delhi has seen significant land use/cover changes during this period.Not Availabl

Not Available

Journal articleWheat (Tritium aestivum L.) is the major food crop of India contributing 12 per cent of the total food grain production, covering an area of 31.5 Mha with production and productivity of 86.5 Mt and 2.8 tha-1 respectively (http://eands.dacnet.nic.in/). In India, wheat is grown during November to March, as it requires cool and moist weather during the vegetative phase, and warm and dry weather during reproductive phase. Cardinal (minimum, maximum and optimum) temperature is one of the most critical parameter that decides fate of crop productivity in wheat. However, wheat sowing after rice is delayed because of late harvesting of rice, large turn around time and poor soil tilth of seed bed which forces delaying of wheat sowing to varying degrees. Wheat yield under such circumstances is mainly affected by terminal heat and water stress.Reproductive phase is the ultimate determinant of yield, if faces high temperature stress shows a significant impact on yield (Mitra and Bhatia, 2008). Different wheat cultivars take different time from germination to maturity under varied agro-climatic condition. Therefore, crop development phases alone cannot be considered as a good predictor for measuring abiotic stress. The more scientific way of characterizing abiotic stressis through meteorological indices like growing degreedays, heat use efficiency, etc. Considering all these, a study was undertaken to investigate the impact of sowing date on yield, heat and water use efficiency of three wheat cultivars in Indo-Gangetic Plains of India.Not Availabl

Not Available

Not AvailableIn this work, we estimated soil moisture (SM) by using dielectric constant properties of soil with radar backscattering coefficient (bc) from simulated annealing techniques of RISAT-1 (radar imaging satellite, based on synthetic aperture radar (SAR) technique) data. We examined the performance of simulated annealing in retrieving SM where the vegetation cover is not very high (NDVI ≈ 0.35 for wheat-dominated area on January 19, 2013).To overcome the land surface model limits on SM estimation accuracy, point measurement spatial coverage limits, and microwave remote sensing spatial-temporal sampling limits, we reduced uncertainties through a combination of these approaches. Near-surface SM measurements from the 5.35-GHz (C-band) channels of RISAT-1 were collocated against ground-truth data (collected during the flight time of RISAT-1 over the study area), to establish SAR-SM relationships for FRS-1(circular horizontal (RH) and circular vertical (RV)) data set of RISAT-1. Comparison with the limited ground-based point (total 24 points) measurements of SM content exhibited a net improvement when near-surface SM observations were assimilated. Comparison of the SM derived from the sigma naught (σ 0) (of RISAT-1 data set FRS-1) using the inversion algorithm with the observed measurements (using time domain reflectometry) of SM showed root mean square error of 0.24, nRMSE = 0.03, R-RMSE = 0.38, MAE = 0.63, NRMSE = 1.02, NSE = 1, d = 0.87, r 2 = 0.65, and RMSE% = 12.79 for RH polarized image while RV polarized image failed each statistical test for predicting good SM with respect to the observed SM. The ability to extract additional information comes at the expense of including more measurements, especially at frequencies lower than the L-band. This approach is therefore intended for future space-borne systems.ISRO-SAC RISAT-1 Utilization Projec

Not Available

Not AvailableWe have estimated soil moisture (SM) by using circular horizontal polarization backscattering coefficient (σoRH), differences of circular vertical and horizontal σo(σoRV−σoRH) from FRS-1 data of Radar Imaging Satellite (RISAT-1) and surface roughness in terms of RMS height (RMSheight). We examined the performance of FRS-1 in retrieving SM under wheat crop at tillering stage. Results revealed that it is possible to develop a good semi-empirical model (SEM) to estimate SM of the upper soil layer using RISAT-1 SAR data rather than using existing empirical model based on only single parameter, i.e., σo. Near surface SM measurements were related to σoRH, σoRV−σoRH derived using 5.35 GHz (C-band) image of RISAT-1 and RMSheight. The roughness component derived in terms of RMSheight showed a good positive correlation with σoRV−σoRH(R2=0.65). By considering all the major influencing factors (σoRH, σoRV−σoRH, and RMSheight), an SEM was developed where SM (volumetric) predicted values depend on σoRH, σoRV−σoRH, and RMSheight. This SEM showed R2 of 0.87 and adjusted R2 of 0.85, multiple R=0.94 and with standard error of 0.05 at 95% confidence level. Validation of the SM derived from semi-empirical model with observed measurement (SMObserved) showed root mean square error (RMSE) = 0.06, relative-RMSE (R-RMSE) = 0.18, mean absolute error (MAE) = 0.04, normalized RMSE (NRMSE) = 0.17, Nash–Sutcliffe efficiency (NSE) = 0.91 (≈1), index of agreement (d) = 1, coefficient of determination (R2)=0.87, mean bias error (MBE) = 0.04, standard error of estimate (SEE) = 0.10, volume error (VE) = 0.15, variance of the distribution of differences (S2d)=0.004. The developed SEM showed better performance in estimating SM than Topp empirical model which is based only on σo. By using the developed SEM, top soil SM can be estimated with low mean absolute percent error (MAPE) = 1.39 and can be used for operational applications.Not Availabl

Not Available

Not AvailableFive empirical methods (viz. Cuenca, 1989; Snyder, 1992; Orang, 1998; Pereira, 1995 and Allen and Pruit, 1991) were evaluated to find out Kp using daily weather data (temperature, relative humidity and wind speed) of Indian Agricultural Research Institute station over the years 1997 to 2011. It was observed that the measured Kp values showed bi-modal variation during the year with values ranging between 0.72 to 0.93, being lower in the summer months and higher in rainy and winter months. Out of the five methods, Snyder method was found to be the best for estimating Kp with RMSE of 0.05, and MAD of 0.04. The ETo estimated with Kp of Snyder method also showed lowest RMSE of 0.19, and MAD about 0.16. It is recommended that temporal variation in Kp should be computed for each station for estimation of ETo and Snyder method is recommended for estimating Kp in semi-arid environments.Not Availabl

Not Available

Not AvailableA field experiment was conducted during the winter (rabi) season of 2009–10 and 2010–11 on a sandy-loam soil in New Delhi, to study the effect of nitrogen levels on the water, radiation and nitrogen-use efficiencies of wheat [Triticum aestivum (L.) emend. Fiori. & Paol.] cultivars. The treatments comprising 2 wheat cultivars (‘PBW 502’ and ‘DBW 17’) and 3 nitrogen levels (N0: 0kg N/ha, N60: 60 kg N/ha and N120: 120 kg N/ha) were laid out in factorial randomized block design (RBD). Both cultivars were statistically at par for grain yield, above-ground biomass yield, water-use efficiency (WUE) and radiation-use efficiency (RUE). Treatments N120 registered 71% and 25% higher grain yield than N0 and N60 treatments respectively. Water-use efficiency (WUE) of N120 (9.92 kg/ha/mm) was significantly highest, followed by N60 (8.40 kg/ha/mm) and N0 (6.56 kg/ha/mm) treatments. Similarly, radiation-use efficiency (RUE) of N120 (2.49 gm/MJ) was significantly higher than N60 (1.90 gm/MJ) and N0 (1.85 gm/MJ) treatments. The partial factor productivity of nitrogen (PFPN) of the cultivar ‘PBW 502’ (48.96 kg grain/kg nitrogen applied) was significantly higher than that of ‘DBW 17’ (42.23 kg grain/kg nitrogen applied). Nitrogen @ 60 kg/ha (N60) showed significantly higher PFPN (56.08 kg grain/kg nitrogen applied) than N120 (35.10 kg grain/kg nitrogen applied) treatment. Therefore, cultivar ‘PBW 502’ or cultivar ‘DBW 17’ can be grown with 120 kg N/ha for obtaining higher grain yield, above ground biomass, WUE and RUE in the semi-arid tropical environment of Delhi region.Not Availabl

Not Available

Not AvailableThe Vasai creek, the Manori creek and the Thane creek are estuarine creeks in the Arabian Sea near Mumbai. This area has the highest economic development rates in India. In this estuarine area, extensive land use change including embankments was observed and various constructions have taken place due to rapid urbanization and industrialization. Improper and unplanned sustainable coastal zone management may lead to severe environmental problems such as sea water intrusion, coastal erosion, siltation of river channels and land subsidence, etc. This study evaluates the utility of satellite remote sensing imageries by deploying multi- temporal Landsat series satellite data like Multispectral scanner (MSS), Thematic mapper-5 (TM5) and Operational land imager (OLI) and high-resolution Google earth imagery including a topographic map of Mumbai also. From the change analysis performed through this study, huge variations in the position of the coastline were observed. The Thane creek shows very drastic change near Sewri while Vasai creek near Rai village. The Manori creek shows an overall shrink in its area. At some places on the coastline, large sediment depositions were observed. The Jawaharlal Nehru (JLN) port trust area shows vast change due to the encroachment of sea water. In 1954, the area where current JLN port trust is established has only 0.65 km2 area, but after land reclamation and development in sea water for JLN port trust, the area converted to 3.94 km2 in the year 2015, depicting a vast change of area as 0.5 km2 per year. One of the most noticeable impacts of coastline changes in the study area is the narrowing down of all estuarine creeks at many places and extension of JLN port trust into sea water. Coastline and coastal area change detection are important for environment planners and to protect coasts from climate change.Not Availabl