Repositorio Nacional

The Indo-Gangetic Plains (IGP) in north-west (NW) India are facing a severe decline in ground water due to prevalent rice-based cropping systems. To combat this issue, conservation agriculture (CA) with an alternative crop/s, such as maize, is being promoted. Recently, surface drip fertigation has also been evaluated as a viable option to address low-nutrient use efficiency and water scarcity problems for cereals. While the individual benefits of CA and sub-surface drip (SSD) irrigation on water economy are well-established, information regarding their combined effect in cereal-based systems is lacking. Therefore, we conducted a two-year field experiment in maize, under an ongoing CA-based maize-wheat system, to evaluate the complementarity of CA with SSD irrigation through two technological interventions–– CA+ (residue retained CA + SSD), PCA+ (partial CA without residue + SSD) – at different N rates (0, 120 and 150 kg N ha-1) in comparison to traditional furrow irrigated (FI) CA and conventional tillage (CT) at 120 kg N ha-1. Our results showed that CA+ had the highest grain yield (8.2 t ha-1), followed by PCA+ (8.1 t ha-1). The grain yield under CA+ at 150 kg N ha-1 was 27% and 30% higher than CA and CT, respectively. Even at the same N level (120 kg N ha-1), CA+ outperformed CA and CT by 16% and 18%, respectively. The physiological performance of maize also revealed that CA+ based plots with 120 kg N ha-1 had 12% and 3% higher photosynthesis rate at knee-high and silking, respectively compared to FI-CA and CT. Overall, compared to the FI-CA and CT, SSD-based CA+ and PCA+ saved 54% irrigation water and increased water productivity (WP) by more than twice. Similarly, a greater number of split N application through fertigation in PCA+ and CA+ increased agronomic nitrogen use efficiency (NUE) and recover efficiency by 8–19% and 14–25%, respectively. Net returns from PCA+ and CA+ at 150 kg N ha-1 were significantly higher by US$ 491 and 456, respectively than the FI-CA and CT treatments. Therefore, CA coupled with SSD provided tangible benefits in terms of yield, irrigation water saving, WP, NUE and profitability. Efforts should be directed towards increasing farmers’ awareness of the benefits of such promising technology for the cultivating food grains and commercial crops such as maize. Concurrently, government support and strict policies are required to enhance the system adaptability.

Net Returns Subsurface Drip Irrigation Subsurface Drip Fertigation CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA EFFICIENCY GRAIN NITROGEN PHOTOSYNTHESIS PHYSIOLOGY WATER SUPPLY CONSERVATION AGRICULTURE CONVENTIONAL TILLAGE FERTIGATION GROUNDWATER NITROGEN-USE EFFICIENCY WATER PRODUCTIVITY

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

Hari Sankar Nayak C.M. Parihar Shankar Lal Jat ML JAT Ahmed Abdallah (2022, [Artículo])

Non-Linear Growth Model Nitrogen Remobilization Right Placement Precision Nitrogen Management CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA GROWTH MODELS NITROGEN NUTRIENT MANAGEMENT

Optimizing nitrogen fertilizer and planting density levels for maize production under current climate conditions in Northwest Ethiopian midlands

Kindie Tesfaye Dereje Ademe Enyew Adgo (2023, [Artículo])

This study determined the most effective plating density (PD) and nitrogen (N) fertilizer rate for well-adapted BH540 medium-maturing maize cultivars for current climate condition in north west Ethiopia midlands. The Decision Support System for Agrotechnology Transfer (DSSAT)-Crop Environment Resource Synthesis (CERES)-Maize model has been utilized to determine the appropriate PD and N-fertilizer rate. An experimental study of PD (55,555, 62500, and 76,900 plants ha−1) and N (138, 207, and 276 kg N ha−1) levels was conducted for 3 years at 4 distinct sites. The DSSAT-CERES-Maize model was calibrated using climate data from 1987 to 2018, physicochemical soil profiling data (wilting point, field capacity, saturation, saturated hydraulic conductivity, root growth factor, bulk density, soil texture, organic carbon, total nitrogen; and soil pH), and agronomic management data from the experiment. After calibration, the DSSAT-CERES-Maize model was able to simulate the phenology and growth parameters of maize in the evaluation data set. The results from analysis of variance revealed that the maximum observed and simulated grain yield, biomass, and leaf area index were recorded from 276 kg N ha−1 and 76,900 plants ha−1 for the BH540 maize variety under the current climate condition. The application of 76,900 plants ha−1 combined with 276 kg N ha−1 significantly increased observed and simulated yield by 25% and 15%, respectively, compared with recommendation. Finally, future research on different N and PD levels in various agroecological zones with different varieties of mature maize types could be conducted for the current and future climate periods.

Maize Model Planting Density CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA MAIZE MODELS SPACING NITROGEN FERTILIZERS YIELDS

Autotrophic denitrification of nitrate rich wastewater in fluidized bed reactors using pyrite and elemental sulfur as electron donors

Maria Federica Carboni Simon Mills SONIA LORENA ARRIAGA GARCIA Gavin Collins Umer Zeeshan Ijaz Piet Nicolaas Luc Lens (2022, [Artículo])

"This study compared denitrification performances and microbial communities in fluidized bed reactors (FBRs) carrying out autotrophic denitrification using elemental sulfur (S0) and pyrite (FeS2) as electron donors. The reactors were operated for 220 days with nitrate loading rates varying between 23 and 200 mg N-NO-3 /Lmiddotd and HRT between 48 and 4 h. The highest denitrification rates achieved were 142.2 and 184.4 mg NNO-3 /Lmiddotd in pyrite and sulfur FBRs, respectively. Pyrite-driven denitrification produced less SO2- 4 and no buffer addition was needed to regulate the pH. The sulfur FBR needed instead CaCO3 to maintain the pH neutral and consequentially more sludge was produced (CaSO4 precipitation). The active community of pyrite-based systems was investigated and Azospira sp., Ferruginibacter sp., Rhodococcus sp. and Pseudomonas sp. were the predominant genera, while Thiobacillus sp. and Sulfurovum sp. dominated the active community in the sulfur FBR. However, Thiobacillus sp. became more dominant when operating at elevated nitrogen loading rate. Patterns of diversity and microbial community assembly were assessed and revealed three distinct stages of microbial community succession which corresponded with the operation of a period of high influent nitrate concentration (135 mg N-NO-3 /L). It is proposed that a high degree of functional redundancy in the initial microbial communities may have helped both reactors to respond better to such high influent nitrate concentration."

Pyrite Elemental sulfur Fluidized bed rector Nitrogen removal 16S rRNA Community assembly CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA