North-western Indo-Gangetic Plains Research Articles

Adoption and Impact of Wheat variety HD 3086: An analysis using structural equation modeling

Varietal development plays a crucial role in improving the overall yield of a crop and the impact assessment of a particular variety is essential to support this statement. Present study was carried out in North-Western Indo-Gangetic Plains (Punjab, Haryana and Western Uttar Pradesh) in India during 2017–18 to observe the response on the yield with the adoption of newly developed yellow rust resistant wheat variety HD 3086. The Structural Equation Model (SEM) was used to establish a relationship between the rate of adoption and factors affecting the same. Households (1000) were surveyed through random sampling for the study. Punjab was found to have the highest adoption rate amongst the 3 states followed by Haryana. This study has observed an increasing trend in coverage of farm area under HD 3086 in Punjab and Haryana. However, in Uttar Pradesh creating awareness among the seed companies and Krishi Vigyan Kendra (KVK) centres was found imperative for the multiplication of HD 3086.

Rice yield gaps and nitrogen-use efficiency in the Northwestern Indo-Gangetic Plains of India: Evidence based insights from heterogeneous farmers’ practices

A large database of individual farmer field data (n = 4,107) for rice production in the Northwestern Indo-Gangetic Plains of India was used to decompose rice yield gaps and to investigate the scope to reduce nitrogen (N) inputs without compromising yields. Stochastic frontier analysis was used to disentangle efficiency and resource yield gaps, whereas data on rice yield potential in the region were retrieved from the Global Yield Gap Atlas to estimate the technology yield gap. Rice yield gaps were small (ca. 2.7 t ha−1, or 20% of potential yield, Yp) and mostly attributed to the technology yield gap (ca. 1.8 t ha−1, or ca. 15% of Yp). Efficiency and resource yield gaps were negligible (less than 5% of Yp in most districts). Small yield gaps were associated with high input use, particularly irrigation water and N, for which small yield responses were observed. N partial factor productivity (PFP-N) was 45–50 kg grain kg−1 N for fields with efficient N management and approximately 20% lower for the fields with inefficient N management. Improving PFP-N appears to be best achieved through better matching of N rates to the variety types cultivated and by adjusting the amount of urea applied in the 3rd split in correspondance with the amount of diammonium-phosphate applied earlier in the season. Future studies should assess the potential to reduce irrigation water without compromising rice yield and to broaden the assessment presented here to other indicators and at the cropping systems level.

Physiological evaluation of growth and yield variation of mustard (Brassica juncea) varieties under organic products in North-Western Indo-Gangetic Plains

A field experiment was conducted for two years to analyze the physiological basis of variation in the growth and yield of popular mustard varieties under organic production. Twelve mustard varieties of varied duration and agroclimatic suitability were evaluated in a randomized complete block design. Results revealed that varieties NRCHB-506, RH-406, and RGN-229, being at par, registered significantly maximum leaf area index, photosynthesis rate, and chlorophyll content at all the crop growth stages, i.e., 30, 60 and 90 DAS. During both the intervals, i.e., 30-40 and 80-90 DAS, variety RH-406 followed by RGN-229 registered maximum crop growth rate, whereas,in NRCHB-101, the lowest crop growth rate was observed. At each crop growth stage, photosynthesis rate has a significant positive correlation with leaf area index, chlorophyll content, crop growth rate during 30-40 and 80-90 DAS. Varieties Pusa Mustard-25 (5.8) and Pusa Mustard-26 (5.7) recorded significantly higher primary branches plant-1. However, varieties Pusa Tarak, RH-406, and RGN-229 recorded the significantly highest number of secondary branches plant-1. Being at par, varieties NRCHB-506, RH-406, RGN-229, and Pusa Bold recorded a significantly higher number of silique plant-1, seed yield,and stover yield than other varieties. The seed yield was found significantly and positively correlated with the crop growth rate at 80-90 DAS (r=0.600**), chlorophyll content at 90 DAS (r=0.558**), and silique plant-1(r=0.518**).Therefore, it is inferred that varieties like RH-406, RGN-229, and NRCHB-506 are suitable to grow under organic nutrient management in the prevailing agro-climatic conditions.

Status of herbicide resistance in Phalaris minor in wheat in Haryana

Herbicide resistance in little seed canary grass (Phalaris minor Retz.) in wheat is the major sustainability issue, which puts the rice-wheat (R-W) system in north-western Indo-Gangetic Plains (IGP) under serious threat. To assess the resistance level, a questionnaires based survey with a systematic approach was conducted during rabi 2017-18 in five districts (Yamuna Nagar, Kaithal, Karnal, Fatehabad and Rohtak) of Haryana. The study revealed that at present, farmers of Haryana are closely back to square one, similar to the situation of herbicide resistance in P. minor like 1990's and currently, no herbicide is satisfactorily effective against resistant P. minor. Farmers are using every possible combination of herbicides in a hit and trial way. In 2017-18, half of the farmers (50%) went for the second spray, 13% applied the third spray, and even 3% of farmers opted for the fourth spray. The same pattern followed in the case of herbicide dose; in 2017-18, 38% of farmers opted for 2-4 X-dose, 16% of farmers for 4-6 X-dose, 3% of farmers for 6-8 X-dose, and even one percent farmers applied 8-10 X-dose. Negative relationship between percent control with higher dose (X) (Chi-Square value 72.560a, DF = 12 and p = <0.001) and multiple sprays (Chi-Square 67.076a, DF = 8 and P = <0.001) recorded during 2017-18 also indicates strong chances/evidences of herbicide resistance development.

Net Ecosystem Exchange of Carbon Dioxide in Rice-Spring Wheat System of Northwestern Indo-Gangetic Plains

Rice growing under anaerobic conditions followed by spring wheat under an aerobic environment differentially impact the net ecosystem exchange (NEE) of carbon dioxide (CO2) in rice-wheat systems of the north-western Indo-Gangetic Plains (IGP). This is the first estimation of the NEE in a rice-spring wheat sequence via the eddy covariance technique in the north-western Indo-Gangetic Plains, which was partitioned into gross primary productivity (GPP) and ecosystem respiration (RE) and correlated with the environmental variables. Higher CO2 uptake of −10.43 g C m−2 d−1 was observed in wheat during heading as compared to −7.12 g C m−2 d−1 in rice. The net uptake of CO2 was 25% lower in rice. The average daily NEE over the crop season was −3.74 and −5.01 g C m−2 d−1 in rice and wheat, respectively. The RE varied from 0.07–9.00 g C m−2 d−1 in rice and from 0.05–7.09 g C m−2 d−1 in wheat. The RE was positively correlated with soil temperature at 5 cm depth (0.543, p < 0.01) in rice and with air temperature (0.294, p < 0.01) in wheat. The GPP was positively correlated with air temperature (0.129, p < 0.05) and negatively correlated with vapor pressure deficit (VPD) (−0.315, p < 0.01) in rice. In wheat, GPP was positively correlated with air temperature (0.444, p < 0.01) and soil moisture (0.471, p < 0.01). The rate of GPP over the crop duration was nearly the same in both rice and wheat, however, the RE was higher in rice as compared to wheat, thus, the ratio of cumulative RE/GPP was 0.51 in rice and much lower at 0.34 in spring wheat. Rice contributed 46% and 43% to the annual totals of RE and GPP, respectively, while spring wheat contributed 36% and 51%. The NEE of CO2 was higher in spring wheat at −576 g C m−2 d−1 as compared to −368 g C m−2 in rice. Thus, while estimating the carbon sink potential in the intensively cultivated northern IGP, we need to consider that spring wheat may be a moderately stronger sink of CO2 as compared to rice in the rice-wheat system.

Productivity and Profitability of Fodder Cowpea Cultivars under Various Zinc Management Practices in IGP of India

Background: Soils of North-Western Indo-Gangetic plains (IGP) are deficient in zinc content which may lead to lower forage yield of cowpea. Henceforth, the adequate supply of zinc either through soil or foliar spray and selection of suitable cultivar of cowpea could enhance the fodder productivity.Methods: A field experiment was laid out in factorial randomized block design during Kharif season, 2019 to assess the effect of different zinc management practices (control; 10 kg ZnSO4; 20 kg ZnSO4; 0.5% ZnSO4 foliar spray at 20 DAS; 0.5% ZnSO4 foliar spray at 20 and 40 DAS) on productivity and profitability of cowpea cultivars (C-152; MFC-08-14; MFC-09-1) and post-harvest fertility status of soil.Result: Cowpea cv. C-152 showed the highest growth attributes, green fodder yield, nutrient content as well as uptake and net returns. Among different zinc management practices, the application of 20 kg ZnSO4 as basal application or 0.5% ZnSO4 foliar spray at 20 and 40 DAS recorded significantly highest growth, green fodder yield, nutrient content as well as uptake and net returns. Significantly highest soil OC, available N, K and Zn were also noted under these treatments. It is inferred that cowpea cv. C-152 and application of either 20 kg ZnSO4 as basal or 0.5% ZnSO4 as foliar spray at 20 and 40 DAS were found the most productive and profitable approach and sustained the soil fertility status.

Energy budgeting and carbon footprints of three tillage systems in maize-wheat sequence of north-western Indo-Gangetic Plains

Intensive tillage often contributes to yield gains but there is a tradeoff with energy consumption and carbon footprint (CF) challenging agricultural and environmental sustainability. Studies in the past examined the effect of tillage practices on one or two of the metrics viz., crop productivity or energy auditing or CF and a comprehensive evaluation of the three in a single study to identify cleaner and climate-smart production practice is generally lacking. This study quantified the effect of conventional (CT), deep (DT) and no-tillage (NT) with and without straw mulch on energy budgeting, crop productivity, CF and greenhouse gas intensity (GHGI) in maize-wheat sequence in a split plot design field experiment. No-tillage in maize curtailed energy input by 38.4% and 20.1% compared to DT and CT, respectively. Per tonne of maize grain production, NT with mulch (NTM) saved 1044 MJ of energy (41%) and increased grain yield by 35.3% compared with CT without mulch (CTM0). Although grain yield and net energy gain was higher under DT with mulch (DTM) than NTM, yet latter resulted in significantly higher energy productivity and energy use efficiency. Minimum C equivalent emissions and maximum gain in soil organic C in NTM lowered the CF resulting in highest C efficient and sustainable management. Minimal GHGI without yield penalty was achieved by adopting NT with mulching. Energy and C budgeting revealed that NT coupled with mulching is the most energy and C efficient practice followed by DTM; CT without residue retention is the least efficient management practice for intensively cultivated maize-wheat system in north-western Indo-Gangetic Plains.

Quantification of Multiple Herbicide Resistance in Phalaris minor Populations of the North-Western Indo-Gangetic Plains of India

Multiple resistance to different herbicides used for management of Phalaris minor Retz. in Northern India was quantified for its two populations—one susceptible and the other resistant to acetyl-CoA carboxylase (ACCase) inhibitor herbicide clodinafop-propargyl. Clodinafop-propargyl and pinoxaden at their recommended dose recorded complete control of clodinafop-propargyl susceptible P. minor population, whereas sulfosulfuron and mesosulfuron plus iodosulfuron at their recommended dose exhibited 48.5 and 51.5% control of this population. In clodinafop-propargyl-resistant P. minor population, sulfosulfuron and mesosulfuron plus iodosulfuron even at 4X dose did not cause any mortality; however, pinoxaden at 4X dose caused complete mortality at 30 DAS. Metribuzin plus clodinafop-propargyl applied at all the doses (0.25X, 0.5X, X, 2X and 4X) recorded complete mortality of both the populations. Application of different herbicides caused reduction in chlorophyll fluorescence and chlorophyll content index in leaves of both the populations in a dose-dependent manner. But the magnitude of reduction was higher in susceptible population as compared to the resistant population.

Micronutrient uptake in wheat as affected by long term zero tillage and different moisture regimes in legume based cropping systems of north-western Indo-gangetic plains

A field experiment “Micronutrient uptake in wheat as affected by long term zero tillage and different moisture regimes in legume based cropping systems of north-western Indo-Gangetic Plains was conducted during 2017-18 and 2018-19 on an on-going long term experiment on ‘Effect of varying moisture regimes in zero-till wheat succeeding mungbean and sorghum’ since 2006 at, CCS HAU, Hisar. The experiments consisted of two cropping systems (mungbean-wheat, MW and sorghum-wheat, SW), three tillage practices viz. CT-CT (conventional tillage in both kharif & rabi seasons), CT-ZT (conventional tillage in kharif & zero tillage in rabi seasons) and ZT-ZT (zero tillage in both kharif & rabi seasons); and three moisture regimes {IW/CPE = 0.60(M0.60), 0.75 (M0.75) and 0.90 (M0.90)}. The adoption of ZT-ZT practice increased uptake of micronutrients (Fe, Mn, Zn and Cu) as compared to CT-ZT and CT-CT practices in all the moisture regimes under mungbean-wheat and sorghum-wheat cropping systems. The uptake of Fe was significantly higher in mungbean-wheat cropping system (16.56 and 21.19%) as compared to sorghum-wheat cropping system by grain and straw, respectively. It was significantly higher in ZT-ZT (38.49 and 34.34; 35.16 and 19.53%) and CT-ZT (23.22 and 10.95 and 17.37 and 6.69%) as compared to CT-CT over all the moisture regimes under mungbean-wheat and sorghum-wheat cropping systems by grain and straw, respectively. In present study, uptake of Fe was significantly higher at M0.90 (16.60 and 13.59; and 15.71 and 12.74%) and M0.75 (8.70 and 5.87; and 6.06 and 4.98%) as compared to M0.60 over all the tillage practices in mungbean-wheat and sorghum-wheat cropping systems by grain and straw, respectively. The similar trends were observed for uptake of Mn, Zn and Cu by the wheat grain and straw. Therefore long term zero tillage with inclusion of legumes can be a promising alternative to sustainably increase uptake of micronutrients in soil for cereal-cereal cropping systems which ultimately plays a pivotal role to sustain the crop productivity and optimum ecosystem functioning with improving soil health.

Phalaris minor management in wheat by post-emergence application of metribuzin based tank-mixed herbicides in north-western Indo-Gangetic Plains

Phalaris minor management in wheat by post-emergence application of metribuzin based tank-mixed herbicides in north-western Indo-Gangetic Plains

Conservation agriculture effects on weed dynamics and maize productivity in maize- wheat- greengram system in north-western Indo-Gangetic Plains of India

Conservation agriculture effects on weed dynamics and maize productivity in maize- wheat- greengram system in north-western Indo-Gangetic Plains of India

Effect of long term zero tillage and different moisture regimes on NPK uptake by wheat in legume based cropping systems of north-western Indo-gangetic plains

Effect of long term zero tillage and different moisture regimes on NPK uptake by wheat in legume based cropping systems of north-western Indo-gangetic plains

Soil quality indices in a conservation agriculture based rice-mustard cropping system in North-western Indo-Gangetic Plains

The systematic research on the effect of medium-term conservation agriculture (CA) on soil quality, especially under the rice (Oryza sativa L.)-based cropping systems is limited. Hence, the specific objective of the study was to develop soil quality indices with key soil physical, chemical and biological indicators under the conservation and conventional tillage practices in a rice–mustard [Brassica juncea (L.) Czern.] cropping system. Eight treatment combinations including tillage and crop establishment, crop residue and cropping system intensification with inclusion of short duration summer mungbean [Vigna radiata (L.) Wilczek] were adopted in rice - mustard cropping system in hot semi-arid, sub-tropical north-western Indo-Gangetic Plains agro-ecoregion of India. Soil samples collected from topsoil (0−5 cm) and 5−15 cm soil layer were analyzed for 15 physical, chemical and biological properties to develop unified soil quality index (SQI) through principal component analysis (PCA). The highest SQI was obtained in the zero till direct seeded rice (ZTDSR) – zero till mustard (ZTM) –ZT summer mungbean (ZTSMB (+R) (mungbean residue in ZTDSR - rice residue in ZTM- mustard residue in ZTSMB) treatment followed by the ZTDSR + BM (brown manuring) – ZTM (+R) (mustard residue in ZTDSR with BM – rice residue in ZTM). The lowest SQI was obtained in transplanted puddled rice (TPR) - conventional till mustard (CTM) for both soil layers. The identified key indicators for SQI in this Inceptisol were saturated hydraulic conductivity (Ks), pH, total N, available P, and available K. Besides, the plots under ZTDSR – ZTM – ZTSMB (+R) resulted in 14 % higher total organic C in topsoil and 28 % higher aggregate stability than the TPR - CTM plots. This ZTDSR – ZTM -ZTSMB (+R) treatment had 65 % higher surface soil microbial biomass C than the TPR – CTM treatment. The ZTDSR – ZTM -ZTSMB (+R) treatment also led to higher Ks, which was in the order of triple ZT > double ZT > ZT > conventional tillage. Thus, the medium-term CA with triple or double zero tillage with crop residue retention could lead to maintain agricultural sustainability under rice-mustard system. Hence, it may be recommended to the farmers for adoption.

Weed control and rice yield stability studies across diverse tillage and crop establishment systems under on-farm environments

In zero-till direct seeded rice (DSR), systematic information pertaining to weed management under on-farm conditions for medium- or long-term is lacking. Therefore, on-farm adaptive trials were conducted to find out the effect of different crop establishment and weed management practices on yield stability and weed dynamics over the years at Faridabad and Sonepat districts of Haryana, India. Results showed that DSR with residue (DSRR) coupled with pretilachlor as pre-emergence (PE) @ 0.75 kg ha−1 followed by bispyribac-sodium as post-emergence (POE) @ 0.025 kg ha-1 (PretBis) or cyhalofop butyl @ 0.060 kg ha-1 (PretCy) resulted in rice grain yield (5.38 t ha-1 and 5.33 t ha-1, respectively) statistically at par with transplanted rice (TPR)-PretBis (5.30 t ha-1) and TPR-PretCy (5.21 t ha-1). PretBis produced 32.3 % higher grain yield as compared to farmers’ practice (FP). Higher broad-leaved weeds (BLWs) biomass was recorded under DSR (8.25 g m-2), followed by DSRR (4.58 g m-2) and TPR (3.99 g m-2). Whereas, among weed management practices, PretBis had least BLWs biomass (4.17 g m-2) followed by PretCy (4.77 g m-2). Biomass of narrow leaved weeds (NLWs) and sedges was found lowest under PretCy (3.63 g m-2 and 3.77 g m-2). GGE biplot analysis of biomass of BLWs and NLWs reveals that PretBis and PretCy, respectively had the highest-ranking owing to their stability across the environments (location x year). In year x location environments, last three years of study were in the same mega environments, which indicated stability in weed biomass and population reduction from third year onwards. Yield stability was highest under DSRR-PretCy followed by DSRR-PretBis. The study highlights that, under north-western Indo-Gangetic plains, if the weeds are managed properly, DSRR can be adopted without significant yield reduction during initial years and comparable yield to TPR and improved soil fertility in the long-term.

Soil quality and carbon sequestration under conservation agriculture with balanced nutrition in intensive cereal-based system

Conventional tillage practices and imbalanced use of inorganic fertilizers is well known to result in poor soil health. Alternative tillage and precision nutrient management are important strategies for tackling the issues of soil health deterioration, particularly in cereal-based intensive cropping systems. Therefore, we conducted a 4-year study with the objective of (a) monitoring the changes in soil physical, biological and chemical properties and crop productivity, (b) development of soil quality index-SQI, and monitor its’ changes against system productivity as management goal, and (c) studying the changes in soil organic carbon-SOC in relation to annual C input. The experiment was laid out in a split-plot design with 3-tillage practices [zero tillage-ZT; permanent beds-PB; and conventional tillage-CT] and 4-nutrient management strategies [Control (unfertilized), farmers’ fertilizer practice-FFP, recommended fertilizers doses-Ad-hoc and site specific nutrient management-SSNM] under a continuous maize (Zea mays L.) - wheat (Triticum aestivum L.)- mungbean (Vigna radiata L. Wilczek) rotation in a sandy loam soil (Typic Haplustept) of north-western Indo-Gangetic plains (NW-IGP) of India. The ZT/PB with SSNM/Ad-hoc nutrient management resulted in higher values of a) physical parameters viz., water stable aggregates >250 μm, saturated hydraulic conductivity (Ksat) and mean weight diameter-MWD, b) chemical parameters viz., SOC, available N, P, and K, and c) biological parameters viz., microbial biomass carbon and enzyme activities (fluorescein diacetate hydrolase, dehydrogenase, ß-glucosidase and alkaline phosphatase) compared with CT and unfertilized treatments. The CA practices recorded an increase in WSA (12–21%), MWD (14–29%), and Ksat (11–14%) compared with CT at the 0-0.15 m and 0.15–0.30 m soil depths, respectively. The PB-SSNM registered (44.1%) higher SOC content as compared to CT-unfertilized plots. Values for MBC, FDA and βGA declined in the order SSNM=Ad-hoc>FFP > Control. While, the DHA declined in the order SSNM>Ad-hoc=FFP > Control. Principal component analysis included MWD, SOC and available K in the minimum data set (MDS) as the soil quality indicators. Adoption of PB/ZT resulted ∼22.5% higher SQI compared with CT. The SSNM plots improved SQI by ∼19.3% and ∼5.3% over unfertilized and FFP. The SSNM based CA practices attained a significantly higher annual C sequestration rate than other treatments. Therefore, adoption of CA with SSNM and Ad-hoc nutrient management in intensive cereal based systems of NW-IGP is essential for improving nutrient cycling, soil quality, crop productivity and C-sequestration potential.

Impacts of sequential herbicides and residue mulching on weeds and productivity and profitability of vegetable pea in North-western Indo-Gangetic Plains

Vegetable pea (hereafter referred to as pea) is heavily infested with weeds, which can cause yield losses up to 39%. Only pre-emergence herbicide is not enough to control diverse weeds. Its efficacy is greatly affected by soil surface dryness during winter. Integration of other options with herbicides may provide effective weed management. Therefore, this experiment was designed to evaluate the effects of combinations of pre- and/or post-emergence herbicides, residue retention, mechanical weeding on weeds in pea. Results showed that the applications of pendimethalin 0.5 kg a.i. (active ingredient) ha-1 as pre-emergence + residue 2 t ha-1 followed by imazethapyr 0.075 kg a.i. ha-1 as post-emergence gave comparable pea yield with weed-free control, which was 79.6% and 77.3% higher, respectively in first and second year than that in unweeded control. This treatment resulted in higher weed control efficiency (68% and 70%), leaf area index (4.90 and 5.52) and biomass (5.38 and 5.72 g plant-1) of pea, net returns and net benefit:cost than most other treatments. Contrast analysis revealed that crop residue mulch was superior to no residue and cono-weeding, by giving 41.9-55.5% and 25.5-29.6% higher pea yield, respectively. The residues of pendimethalin, imazethapyr, and quizalofop in pea and soil were below detectable level (0.05 mg kg-1) in all treatments, except two treatments, which, otherwise, had pendimethalin residue below maximum residue limit (0.1 mg kg-1). Thus, the combination of pendimethalin, crop residue, and imazethapyr could lead to better weed management and higher pea productivity and profitability without risks of herbicide residue in pea and soil. It would reduce the use and intake of residues into environment of pendimethalin by 50% and imazethapyr by 25%.

Conservation Agriculture in rice-mustard cropping system for five years: Impacts on crop productivity, profitability, water-use efficiency, and soil properties

Developing suitable crop rotations and crop establishment practices is an important mechanism that can enhance factor productivity and sustainability of an agro-ecosystem. However, the impact of Conservation Agriculture (CA) on alternate crop rotation of the most-dominant but tillage- and input-intensive rice (Oryza sativa L.)-wheat (Triticum aestivum (L.) emend Fiori & Paol) rotation of the Indo-Gangetic Plains (IGP) of India is not elaborately studied. Hence, we evaluated the effect of CA on crop and water productivity, profitability, and soil carbon status in rice-mustard (Brassica juncea L.) rotation in the North-western IGP of India for five consecutive years. Eight treatments comprising of tillage, crop residue, brown manuring (BM) using Sesbania bispinosa, and summer mungbean [Vigna radiata (L.) Wilczek] (SMB) were adopted in rice - mustard cropping system. The conventional transplanted puddled rice (TPR) - conventional till mustard (CTM) (∼TPR-CTM) rotation resulted in significantly higher rice grain yield than zero till direct-seeded rice (ZTDSR) – ZT mustard (ZTM) system with or without crop residue in all five years. However, in this regard, the CA-based ZT rice – mustard - SMB with residue [ZTDSR-ZTM-ZTSMB (+R)] was comparable with it during first three years, but was inferior to it in 4th and 5th years. The ZTDSR-ZTM-ZTSMB (+R) had overall 10.9 % lower five-year mean rice yield than that in the TPR-CTM system. This CA-based system gave significantly higher mustard grain yield in all the years (except first year), and the five-year mean mustard yield was 30.3 % higher than in the TPR-CTM. Another CA-based double cropping system having ZTDSR + BM – ZTM (+R) was comparable with TPR-CTM in all the years and resulted in 27.6 % higher five-year mean mustard yield than the TPR–CTM practice. The ZTDSR-ZTM-ZTSMB (+R) practice gave 44 % (including SMB) and 8.1 % (excluding SMB) higher system productivity and significantly higher sustainable yield index of the rice-mustard system compared with the TPR-CTM practice. The ZTDSR-ZTM-ZTSMB (+R) practice encountered significantly lower weed density in mustard in all five years than TPR-CTM system. The cost-benefit analysis revealed that this CA practice fetched higher net returns by INR 53,000 and 21,400 ha−1 from the rice-mustard system with and without SMB, respectively over the TPR-CTM system. Again, this ZTDSR -ZTM- ZTSMB (+R) system led to an increase in irrigation water productivity by 27.8 % in rice and 35.1 % in mustard, and the total water (irrigation + rainfall) productivity by 35.7 % in mustard crop compared with the TPR-CTM system (P ≤ 0.05). This CA-based rice-mustard system resulted in significantly higher very labile (∼50.6 %) and labile (∼47.7 %) carbon concentration at 0–5 cm depth of soil compared to the conventional TPR-CTM system. The CA system being productive, profitable, and resource-efficient can be recommended for North-western IGP of India and in similar agro-ecologies of the tropics and sub-tropics. It can be adopted with suitable site-specific refinement in South-Asian countries, where decline in crop productivity and soil health is a consistent pervasive problem due to continuous cereal-cereal rotation.

Seasonal characteristics of aerosols (PM2.5 and PM10) and their source apportionment using PMF: A four year study over Delhi, India

The present study attempts to explore and compare the seasonal variability in chemical composition and contributions of different sources of fine and coarse fractions of aerosols (PM2.5 and PM10) in Delhi, India from January 2013 to December 2016. The annual average concentrations of PM2.5 and PM10 were 131 ± 79 μg m−3 (range: 17–417 μg m−3) and 238 ± 106 μg m−3 (range: 34–537 μg m−3), respectively. PM2.5 and PM10 samples were chemically characterized to assess their chemical components [i.e. organic carbon (OC), elemental carbon (EC), water soluble inorganic ionic components (WSICs) and heavy and trace elements] and then used for estimation of enrichment factors (EFs) and applied positive matrix factorization (PMF5) model to evaluate their prominent sources on seasonal basis in Delhi. PMF identified eight major sources i.e. Secondary nitrate (SN), secondary sulphate (SS), vehicular emissions (VE), biomass burning (BB), soil dust (SD), fossil fuel combustion (FFC), sodium and magnesium salts (SMS) and industrial emissions (IE). Total carbon contributes ∼28% to the total PM2.5 concentration and 24% to the total PM10 concentration and followed the similar seasonality pattern. SN and SS followed opposite seasonal pattern, where SN was higher during colder seasons while SS was greater during warm seasons. The seasonal differences in VE contributions were not very striking as it prevails evidently most of year. Emissions from BB is one of the major sources in Delhi with larger contribution during winter and post monsoon seasons due to stable meteorological conditions and aggrandized biomass burning (agriculture residue burning in and around the regions; mainly Punjab and Haryana) and domestic heating during the season. Conditional Bivariate Probability Function (CBPF) plots revealed that the maximum concentrations of PM2.5 and PM10 were carried by north westerly winds (north-western Indo Gangetic Plains of India).

Glyphosate use in transgenic maize: Effect on weeds and crop productivity in North-Western Indo-Gangetic Plains of Haryana

Glyphosate use in transgenic maize: Effect on weeds and crop productivity in North-Western Indo-Gangetic Plains of Haryana

Evaluation of maize (Zea mays) cultivars under organic production system in north-western Indo-Gangetic Plains of India

Increased awareness of environmental degradation and growing concern of human health has attracted worldwide attention towards organic farming. A field experiment was carried out during kharif of 2013–2014 to identify suitable maize (Zea mays L.) cultivars having high yield potential under organic production system. Twelve released cultivars of maize varied in duration and nitrogen requirement were evaluated. Results revealed that late maturing cultivars PMH-1 and PMH-3 being at par to each other recorded the significantly higher values of growth parameters like plant height, dry matter accumulation and leaf area index; and yield attributes in terms of cobs plant, cob length, cob girth, grain rows/cob, grains/row and test weight, whereas the extra early cultivars like Vivek QPM-9 being at par with Vivek Hybrid-9 registered the lowest values of growth and yield attributes. The late maturing cultivars like PMH-1, PMH-3, Seed tech-2324 and Bio-9681 produced significantly higher grain yield (>5.0 t/ha) and biological yield (>12.5 t/ha). Cultivars PMH-4 among medium maturity group produced comparable yield with late cultivars. Grain yield across the varied duration cultivars had a significant positive correlation with cob length, grains/row and N uptake. As per their maturity class, the extra early and early cultivars commence silking (<50 days) and physiological maturity (<82 days) significantly earlier than medium and late cultivars. Moreover, extra early cultivars (Vivek Hybrid-9 and Vivek QPM-9) recorded significantly higher protein content in grain amongst the cultivars tested. The late cultivars PMH-1 and PMH-3 being at par with each other recorded the highest N, P and K uptake in plants while lowest nutrient uptake was observed in the extra early Vivek QPM-9 and Vivek Hybrid-9. Late cultivar PMH-3 followed by PMH-1 recorded the highest net returns (` 66,759) and B:C ratio (1.79) of organic maize cultivation. Soil fertility status in terms of organic carbon, available P and K could not be influenced significantly, however the available N content was significantly higher under extra early cultivars Vivek QPM-9 (172.1 kg/ha) and Vivek Hybrid-9 (170.3 kg/ha). Thus, it can be concluded that PMH-1 and PMH-3 cultivars of maize are most suitable for growing in north-western plains region of Uttar Pradesh under organic production system.