Behaviour of Quality Protein Maize (QPM) genotypes under well irrigated and water stress conditions in subtropical climate

Drought or water stress is one of the prime problems affecting production of maize at global level. A major objective of QPM breeding programs in semi arid tropics or subtropical climatic conditions is to increase genetic potential of QPM genotypes under water stress conditions. In order to identify drought tolerant single cross QPM hybrids an experiment with 85 genotypes was conducted under well irrigated and water stress conditions. Six drought tolerance indices viz, mean productivity (MP), geometric mean productivity (GMP), yield index (YI), tolerance index (TOL), stress susceptibility index (SSI), and superiority measures (SM) were used on the basis of grain yield in water stress (Ys) and well irrigated (Yp) conditions. Highest significant positive correlations were observed among MP, GMP and YI indices. The hybrids 75, 38, 27, and 50 were more drought tolerant based on drought tolerance indices. Three dimensional plot, bi-plot and cluster analysis confirmed these results. Principal component analysis reduced six indices down to two components with 90.71% proportional cumulative variance. Genotypes were grouped by two ways cluster analysis (using Ward’s method) based on Yp, Ys and drought tolerance indices. Also, the results of correlation, 3D graphs, bi-plot and cluster analysis reveals that the most suitable indices to screen QPM genotypes in drought stress conditions were MP, GMP and YI. These indices could be used in QPM breeding programs to introduce drought tolerance in single cross hybrids

Multi-environment field testing to identify stable sources of resistance to charcoal rot (Macrophomina phaseolina) disease in tropical maize germplasm

The charcoal rot caused by Macrophomina phaseolina is the devastating component of post flowering stalk rot (PFSR) complex which may cause 25 to 32 % yield loss in maize. Therefore for the first time, the study was carried out with multi-environments screening of 137 inbreds at three and 48 maize hybrids at six environments under artificially created epiphytotics at hot-spot locations to identify stable sources of charcoal rot resistance in Indian maize germplasm. Analysis of variance revealed strong effect of genotype by environment interaction on disease response and therefore indicated its complex nature. The mean disease score was ranging from 2.37 to 7.20 in inbreds, and 3.63 to 6.08 in hybrids. Additive main effects and multiplicative Interactions (AMMI) analysis could identifed, DQL1020, DML339, DML1, DQL1019, CM117-1-1 in inbreds and A-7501, CMH08-287, CMH08-292, BIO-562, and CMH08-350 in hybrids as stable sources of charcoal rot resistance. Each testing site viz., Ludhiana, Hyderabad and Delhi was identified as a separate test environment for screening against charcoal rot disease in India. In this study, AMMI model offers a good tool to assess the stability of genotypes and GGE biplot found an efficient tool to identify the mega environments in multi-environment testing. The identified sources of resistance in inbreds can be used in resistant breeding and hybrids can be recommended for cultivation in charcoal rot disease prone area

Portfolios of Climate Smart Agriculture Practices in Smallholder Rice-Wheat System of Eastern Indo-Gangetic Plains—Crop Productivity, Resource Use Efficiency and Environmental Foot Prints

The conventional tillage based rice-wheat system (RWS) in Indo-genetic plains (IGP) of South Asia is facing diverse challenges like increase in production cost and erratic climatic events. This results in stagnated crop productivity and declined farm profitability with increased emission of greenhouse gases. Therefore, 3-year multi-location farmer’s participatory research trial was conducted to assess the impact of crop establishment and residue management techniques on crop productivity, economic profitability and environmental footprints in RWS. The aim of this study was to analyze the effect of combinations of improved agronomic technologies compared to farmer’s practices (FP) on crop productivity, profitability, resource use efficiency and environmental footprints. The experiment had six scenarios that is, S1-Farmer’s practice; Conventional tillage (CT) without residue; S2-CT with residue, S3- Reduced tillage (RT) with residue + Recommended dose of fertilizer (RDF); S4-RT/zero tillage (ZT) with residue + RDF, S5-ZT with residue + RDF + green seeker + tensiometer + information & communication technology + crop insurance and S6- S5 + site specific nutrient management. Climate smart agriculture practices (CSAPs; mean of S4, S5 and S6) increase system productivity and farm profitability by 10.5% and 29.4% (on 3 yrs’ mean basis), whereas, improved farmers practices (mean of S2 and S3) resulted in only 3.2% and 5.3% increments compared to farmer’s practice (S1), respectively. On an average, CSAPs saved 39.3% of irrigation water and enhanced the irrigation and total water productivity by 53.9% and 18.4% than FP, respectively. In all the 3-years, CSAPs with high adaptive measures enhanced the energy-use-efficiency (EUE) and energy productivity (EP) by 43%–54% and 44%–61%, respectively than FP. In our study, global warming potential (GWP), GHG emission due to consumption energy and greenhouse gas intensity were recorded lower by 43%, 56% and 59% in Climate Smart Agriculture (CSA) with high adaptive measures than farmers practices (3652.7 kg CO2 eq. ha−1 yr−1, 722.2 kg CO2 eq. ha−1 yr−1 and 718.7 Mg kg−1 CO2 eq. ha−1 yr−1). The findings of the present study revealed that CSA with adaption of innovative measures (S6) improved 3-year mean system productivity by 10.5%, profitability by 29.4%, water productivity and energy productivity by 18.3% and 48.9%, respectively than FP. Thus, the results of our 3-year farmer’s participatory study suggest that in a RW system, climate smart agriculture practices have better adaptive capacity and could be a feasible option for attaining higher yields, farm profitability, energy-use efficiency and water productivity with sustained/improved environmental quality in smallholder production systems of Eastern IGP of India and other similar agro-ecologies of South Asia. Finally, the adoption of these CSAPs should be promoted in the RW rotation of IGP to ensure food security, restoration of soil health and to mitigate climate change, the key sustainable development goals (SDGs)

Dependence of temperature sensitivity of soil organic carbon decomposition on nutrient management options under conservation agriculture in a subtropical Inceptisol

Assessment of temperature sensitivity of soil organic carbon (SOC) mineralization from soils of long-term precision conservation agriculture (CA) plots is essential to forecast soil C dynamics. Under CA, varying quantity of inorganic nutrient application had differential impact on SOC. At the same time study of SOC mineralization at different simulated temperatures is important as global climate change affects C-cycle of an agro-ecosystem. To assess the impact of tillage and nutrient management on SOC build-up, a long-term study (five year old) with 3- tillage practices [ZT-zero tillage; PB-permanent beds, & CT-conventional tillage] in main plot and 4-nutrient management strategies [unfertilized, farmer fertilizer practice-FFP, recommended fertilizers-Ad-hoc and a site specific nutrient management-SSNM] in sub-plot in a maize-wheat-mungbean system was chosen. To measure the build-up and thermal sensitivity of SOC, soil samples from 3- depths (0–7.5, 7.5–15 and 15–30 cm) were collected. The kinetics of C-mineralisation was studied through laboratory incubation at 3-temperatures (27, 32 and 37 °C) for 90 days. The PB/ZT and SSNM had significantly higher SOC compared with CT and unfertilized plots, respectively. Although the cumulative C mineralization after 90-days of incubation followed the trend of SOC content among the treatments, while decay rates of SOC mineralization showed somewhat different trend. In all the tillage treatments the percentage of SOC mineralised ranged between 3.3–5.8% at 27 °C, 5.2–8.1% at 32 °C and 7.3–10.9% at 37 °C. At higher temperature, higher SOC decay rates were observed under CT and unfertilized plots compared with PB/ZT and SSNM plots, respectively. The SOC from lower soil depth in CT and unfertilized plots was more temperature sensitive (Q10=4.03 and 4.89, respectively) compared to those under CA-based PB/ZT (Q10=2.63–2.82) and SSNM (Q10=2.15) based balanced nutrition, respectively. The SOC in lower soil depth (7.5–15 and 15–30 cm) is 1.3 and 2.1 times more temperature sensitive respectively than surface soil depth of 0–7.5 cm soil depth. Higher proportion of less labile SOC under CT and unfertilized plots might be the reason for higher temperature sensitivity. In the inevitable and impending global climate change scenario, we might lose a sizeable amount of sequestered C, which is otherwise stable at present ambient temperature

Effect of different tillage and residue management practices on crop and water productivity and economics in maize (Zea mays) based rotations

In recent years, increasing water and labor scarcity & production cost, decreasing farm profitability and climatechange- induced variability are major challenges faced by the farmers of Indo-Gangetic Plains (IGP) in South Asia. Conservation agriculture (CA) based best-bet crop management practices may increase crop productivity, profitability and conserve the natural resources. In a 2-year (2012-2014) study, we assessed the effects of six combinations of tillage and crop establishment (TCE) and residue management options on crop & water productivity, profitability and soil thermal and moisture regimes in maize (Zea mays)-wheat (Triticum aestivum L.) (MW) and maize-chickpea (Cicer arietinum L.) (MC) rotations in Western IGP of India. The treatments consisted of both crops sown on permanent raised beds with residue (PB+R) and without residue (PB-R); zero tilled flat with residue (ZT+R) and without residue (ZT-R) and conventional tilled flat with residue (CT+R) and without residue (CT-R). Overall, 2-year mean maize, wheat and chickpea grain/seed yield was found to be 17.0-23.2, 20.8-24.8 and 22-31.7% higher under CA-based PB+R/ZT+R than CT-R, but it was 5.3-10.9, 4.9-8.4 and 13.8-22.8% higher than CT+R, respectively. The yield of maize, wheat and chickpea was significantly (P<0.05) higher in CA-based PB+R and ZT+R systems compared to CT-R right from first year onwards. The MW and MC, 2-year mean system productivity (based on maize equivalent yield- MEY) was higher by 21.1-21.9 and 18.7-27.5% in CA-based systems (PB+R & ZT+R) than in the CT-R, respectively. CA-based PB+R and ZT+R practices reduced the total system water use in MW and MC rotations by 75-112 mm and 55-90 mm and resulted enhanced system water productivity (WP) compared to CT-R system. Irrespective of crop rotations and TCE practices residue management treatments enhances the soil moisture (in the range of 14.5 to 30.4% during winter and monsoon seasons) and also moderates the soil temperatures. Economic profit for MW and MC rotations was always significantly (P<0.05) higher (168-445 and 215-619 US$/ha/year) in CA-based systems than in CT-R. Findings of our study shows that MW and MC rotations under CA-based system is one of the way for improving crop productivity, WP and farm income with less risk of extreme temperature and moisture stress while sustaining the natural resources in Western IGP of India and other similar agro-ecologies of South Asia

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

Point placement of late vegetative stage nitrogen splits increase the productivity, N-use efficiency and profitability of tropical maize under decade long conservation agriculture

The rising economic and environmental costs of mineral fertilizers associated with lower nutrient use efficiency, and the need to respond the limitations of N fertilization under residue retained condition of conservation agriculture (CA) motivate the research for alternative N placement methods. The third principle of CA, i.e., residue retention on the soil surface hinders the right placement of split applied nitrogen (N). To address this issue, we assessed the impact of three N placement methods, i.e., NPM1: both the N splits were surface band placed, NPM2: the first split of N was sub-surface point placed and second N split (late vegetative stage) was surface band applied, and NPM3: both the N splits were sub-surface point placed, under 4-long-term tillage and residue management (+R) options, i.e., permanent raised bed (PB+R), zero-till flat (ZT+R) conventional till flat (CT+R) and first time zero till flat sowing of the crop on last 10-year fallow land (FZT+R), in an on-going long-term study (since 2008) in maize for three consecutive years (2018–2020). Results showed that sub-surface point placement of both the N splits (NPM3) increased maize grain yield by 4.7, 7.0 and 6.0% (3-years mean basis) compared to NPM2, under CA-based PB, ZT, and FZT plots, respectively. The peak growth rate in the CA-based PB+R plot was advanced by 4-days with a 9.2% higher growth rate compared to CT+R. Similarly, the peak growth rate in NPM3 was 20% higher than NPM1 plots. The changes in soil properties under CA altered the crop growth behavior, while sub-surface point placement of split applied nitrogen (N) increased the grain N content and altered the peak growth rate of maize. The variability in maize grain yield was best described by cob length and number of cobs in long-term tillage and by cob length in N management plots. The cob length and grains per cob were increased by 4.8–8.7 and 8.6–12.8% under CA-based plots compared to CT+R, respectively. The amount of vegetative stage accumulated N remobilized to maize grain was 21.2% higher under PB+R compared to CT+R plots, while the N remobilization in NPM3 was 22.9% higher compared to NPM1 plots. Similarly, the contribution of reproductive stage N uptake to grain was 9–12% higher in CA-NPM3 compared to CT-NPM1 plots. Further, the early and vigorous growth of maize resulted in a higher accumulation of N and its remobilization to the grains in CA-based and N point placed plots. The sub-surface point placement of N (NPM3) resulted in a 12.8, 14.5 and 9.2% higher benefit-cost ratio compared to NPM1 plots in 11th (2018), 12th (2019) and 13th (2020) years of experimentation, respectively. Therefore, the present study visualizes the impact of a decade-long CA and efficient N management on crop growth behavior, N uptake and remobilization and crop productivity and water use efficiency. This study provides evidence to popularize this technology in the CA-systems of Indo-Gangetic Plains and other similar agro-ecologies

Not Available

Not AvailableThe charcoal rot caused by Macrophomina phaseolina is the devastating component of post flowering stalk rot (PFSR) complex which may cause 25 to 32 % yield loss in maize. Therefore for the first time, the study was carried out with multi-environments screening of 137 inbreds at three and 48 maize hybrids at six environments under artificially created epiphytotics at hot-spot locations to identify stable sources of charcoal rot resistance in Indian maize germplasm. Analysis of variance revealed strong effect of genotype by environment interaction on disease response and therefore indicated its complex nature. The mean disease score was ranging from 2.37 to 7.20 in inbreds, and 3.63 to 6.08 in hybrids. Additive main effects and multiplicative Interactions (AMMI) analysis could identifed, DQL1020, DML339, DML1, DQL1019, CM117-1-1 in inbreds and A-7501, CMH08-287, CMH08-292, BIO-562, and CMH08-350 in hybrids as stable sources of charcoal rot resistance. Each testing site viz., Ludhiana, Hyderabad and Delhi was identified as a separate test environment for screening against charcoal rot disease in India. In this study, AMMI model offers a good tool to assess the stability of genotypes and GGE biplot found an efficient tool to identify the mega environments in multi-environment testing. The identified sources of resistance in inbreds can be used in resistant breeding and hybrids can be recommended for cultivation in charcoal rot disease prone area.Not Availabl

Water budgeting in conservation agriculture-based sub-surface drip irrigation in tropical maize using HYDRUS-2D in South Asia

In water scarce regions of South Asia, diversification of rice with maize is being advocated towards sustainability of cereal-based cropping systems. Adoption of innovative agronomic management practices, i.e., conservation agriculture (CA) and sub-surface drip irrigation (SSDI) are considered as key strategies for much needed interventions to address the challenges of water scarcity under projected climate change. Benefits from CA and SSDI concerning water economy are well-established, however, information about their complementarity and water budgeting in cereal-based systems are lacking. A field study was conducted with process-based model (HYDRUS-2D) to understand water transport, root water uptake and components of soil water balance in maize grown in rotation with wheat after five years of continuous adoption of conservation agriculture. In this study, altogether eight treatments comprising of 6 CA+ treatments (CA coupled with SSDI); permanent beds using sub-surface drip (PB-SSD) with (WR) and without (WOR) crop residue at different N rates, 0, 120 and 150 kg N ha−1 were compared with CA (PB using furrow irrigation-FI with crop residue-120 kg N ha−1) and conventional tillage practices (CT) (CT using FI without crop residue-120 kg N ha−1). Results showed that the model could simulate the daily changes in profile soil water content with reasonable accuracy in all the treatments. Simulated soil water balance indicated higher cumulative root water uptake (CRWU), lower cumulative evaporation (CE) and higher soil water retention in CA+ (PB-SSD+ crop residue at 150 and 120 kg N ha−1) than CA and CT plots. Hydrus-2D model efficiency > 0, RMSE between 0.009–0.026 and R2 value between 0.80–0.92 at P < 0.01 indicates that the model is performing efficiently. The mean evaporation from CA+ treatments was 10 and 36% less than CA and CT treatments, respectively. On average, CRWU under CA+ treatments were 14–48% higher than FI treatments. The mean cumulative deep drainage in CA+ plots was 80–100 mm less than CA and CT plots. In CA+ based plots significantly higher biomass production and radiation use efficiency were observed with reduced water use than CA and CT. Therefore, the study justifies the water-saving nature of CA+, while maintaining higher productivity and meeting the transpiration demand of crops and halting unnecessary evaporation and deep drainage losses

Co-implementation of precision nutrient management in long-term conservation agriculture-based systems: A step towards sustainable energy-water-food nexus

The conventionally managed cereal-based cropping systems in the Indo-Gangetic Plains (IGP) of South Asia are energy intensive that overwhelm the farm profits and the environmental footprint. This research addresses a complex nexus between yield-energy-water-GHG footprints-economics of conservation agriculture (CA)-based intensified maize-wheat-mungbean rotation. This study evaluated the effect of long-term CA (2012–2020) with optimum nutrient management (2017–20) on energy budgeting, productivity, water and C-footprints, Water productivity (WP), and economics of the CA-based maize-wheat-mungbean system. CA-based permanent bed- and zero tillage flatbed with preceding crop residue retention were compared with the conventional till with preceding crop residue incorporation. These treatments were factored over three-nutrient management alternatives, i.e., GreenSeeker®-guided-N, site-specific nutrient management (SSNM), and recommended fertilizers' dose (Ad-hoc), were compared with farmers' fertilizers practices (FFP). Permanent bed and zero tillage treatments registered higher systems' productivity (18.2 and 12.0%), net returns (44.7 and 34.7%) and water productivity (35.6% and 22.1%), and C-sequestration (54.8 and 62.3%), respectively, over conventional till. Permanent bed- and zero tillage treatments increased the systems' net energy (NE), energy use efficiency (EUE), energy productivity (EP), and energy intensity (EI) by 22.6 and 14.0; 10.1 and 5.6; 9.7 and 5.4; 28.3 and 24.0%, respectively, over conventional till. Conventional till recorded higher net CO2-eq emission (26.5 and 27.2%), C-footprint (20.8 and 14.5%), and water footprint (27.3 and 18.0%) than permanent bed- and zero tillage treatments. SSNM increased the system's productivity, water productivity, and energy use efficiency, while reducing the system's water- and C-footprints and net CO2-eq emission. Thus, adopting permanent beds as a crop establishment method with SSNM could be a feasible alternative to attain higher productivity, profitability, and resource use efficiency in the maize-wheat-mungbean system in northwest India