Simulation of resource-conserving technologies on productivity, income and greenhouse gas GHG emission in rice-wheat system

The Rice-wheat (RW) cropping system is one of the major agricultural production systems in four Indo-Gangetic Plains (IGP) countries: India, Pakistan, Bangladesh and Nepal of South Asia covering about 32% of the total rice area and 42% of the total wheat area. The excessive utilization of natural resource bases and changing climate are leading to the negative yield trend and plateauing of Rice-wheat (RW) system productivity. The conservation agriculture based efficient and environmental friendly alternative tillage and crop establishment practices have been adopted by the farmers on large scale. A few tools have been evolved to simulate the different tillage and crop establishment. In the present study, InfoRCT (Information on Use of Resource Conserving Technologies), a excel based model integrating biophysical, agronomic, and socioeconomic data to establish input-output relationships related to water, fertilizer, labor, and biocide uses; greenhouse gas (GHG) emissions; biocide residue in soil; and Nitrogen (N) fluxes in the rice-wheat system has been validated for farmer participatory practices. The assessment showed that double no-till system increased the farmer s income, whereas raised-bed systems decreased it compared with the conventional system. The InfoRCT simulated the yield, water-use, net income and biocide residue fairly well. The model has potential to provide assessments of various cultural practices under different scenarios of soil, climate, and crop management on a regional scale

Double no-till and permanent raised beds in maize–wheat rotation of north-western Indo-Gangetic plains of India: Effects on crop yields, water productivity, profitability and soil physical properties

Excessive pumping of groundwater over the years to meet the high water requirement of flooded rice crop and intensive tillage have threatened the sustainability of irrigated rice–wheat system (RWS) in the Indo-Gangetic plains (IGP) of South Asia. Replacement of rice with less water requiring crops such as maize in the RWS and identification of effective strategies for alternate tillage systems will promote sustainable cropping systems in the IGP. To this effect a 3-year field experiment was established with annual maize–wheat rotation in the north-western IGP of India to evaluate the effect of 3 tillage systems (conventional flat, CTF; no-till flat, NTF; permanent raised beds, NTB) on crop production, water use efficiency, economic profitability and soil physical quality. Grain yield of maize was highest (8.2–73.4%) under NTB followed by NTF and CTF across the years. Wheat yield was significantly higher under NTF during the 1st year while tillage practices had non-significant effect in the succeeding two years. On average, maize planted on NTB recorded about 11% lower water use and 16% higher water use efficiency compared to CT. The NTB and NTF required 24.7% and 10.8% less irrigation water than CTF system, respectively with 11.5% higher system productivity and demonstrated higher water productivity. The NTB and NTF systems provided similar net returns (averaged over 3 years) in maize–wheat system (MWS), which were US$ 281 ha−1 higher compared to CTF system. The CTF system had higher bulk density and penetration resistance in 10–15 and 15–20 cm soil layers due to compaction caused by the repeated tillage. The steady-state infiltration rate and soil aggregation (>0.25 mm) were higher under NTB and NTF and lower in the CTF system. Similarly, mean weight diameter (MWD) of aggregates was higher under NTF and NTB compared to CTF. The study reveals that NTB and NTF systems could be more viable options for MWS in order to save input costs and enhance profitability; however, the long-term effects of these alternative technologies need to be studied under varying agro-ecologies

Fertiliser best management practices for maize systems

Maize is an important crop for food and nutritional security in India. Strong market demand and resilience of maize to abiotic and biotic stresses have increased the area and production of maize in the country over the past decade. Productivity of maize, however, has not increased proportionately and significant yield gaps are evident across maize growing areas in the country. Maize is an exhaustive crop and removes large amounts of plant nutrients from the soil to support high biomass production. The 4R Principles of applying right source of nutrients, at the right rate, at the right time and at the right place is expected to increase nutrient use efficiency, productivity and farm profit from maize production and provides opportunity for better environmental stewardship of nutrients. Adaptation of 4R Principle-based site-specific nutrient management decision support tools provides the opportunity for large-scale adoption of improved nutrient management across maize ecologies

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

Long term effect of conservation agriculture in maize rotations on total organic carbon, physical and biological properties of a sandy loam soil in north-western Indo-Gangetic Plains

Maize-based crop rotations are advocated as alternate to rice-based systems in South Asia due to better suitability for diverse ecologies, higher yields with less water use and more palatable maize fodder compared to rice, and increased demand of maize from piggery and poultry industries. Alternate tillage and crop establishment practices are important management strategies for tackling the issues of soil health deterioration and over exploitation of underground water resources, particularly in rice based intensive crop rotations. The conservation agriculture (CA) based tillage and crop establishment practices such as zero tillage (ZT) and permanent raised beds (PB) hold potential to enhance soil organic carbon (SOC), physical and biological properties for sustainability of soil health. Therefore, a long term study was conducted to evaluate the twelve combinations of tillage practices (03) and irrigated intensive maize based crop rotations (04) on organic carbon, physical properties and microbial biomass and enzymatic activities of a sandy loam (Typic Haplustept) soil in north-western India. The tillage practices consisted of ZT, PB and conventional tillage (CT) in main plots and four diversified intensive maize based crop rotations (MWMb: Maize-Wheat-Mungbean, MCS: Maize-Chickpea-Sesbaina, MMuMb: Maize-Mustard-Mungbean, MMS: Maize-Maize-Sesbania) in sub plots. In this study we analysed the SOC, physical and biological properties of soil at various depths after 7 years of continuous ZT, PB and CT in diversified maize rotations. Compared to CT plots, the soil physical properties like water stable aggregates (WSA) > 250 μm were 16.1-32.5% higher, and bulk density (BD) and penetration resistance (PR) showed significant (P < 0.05) decline (11.0–14.3 and 11.2–12.0%) in ZT and PB plots at 0–15 and 15–30 cm soil layers. The soil organic carbon (SOC) increased by 34.6-35.3% at 0–15 cm, and 23.6-26.5% at 15–30 cm soil depths with conservation agriculture (ZT and PB) based crop establishment techniques over CT. Similarly, the soil microbial biomass carbon (MBC) under CA based systems increased by 45–48.9% in 0–30 cm profile depth of a sandy loam (Typic Haplustept) soil. Significant (P < 0.05) improvement in soil enzymatic activities i.e., Fluorescein diacetate, dehydrogenase, β Glucosidase and Alkaline phosphatase was also recorded in the CA based treatments. Significant (P < 0.05) synergistic effects of summer legumes (mungbean and Sesbania) with winter legume/cereal in crop rotations were observed on SOC,WSA, BD, PR and Ksat at 0–15 and 15–30 cm depths. Interaction between tillage and crop rotations were significant (P < 0.05) for soil organic carbon, physical properties and enzymatic activities. Thus our long-term study suggests that CA based crop management with selected diversified maize based rotations (MCS and MWMb) can be advocated as sustainable intensification strategy in light textured soils of north-western India and other similar agro-ecologies of South Asia

Soil organic carbon changes after seven years of conservation agriculture in a rice–wheat system of the eastern Indo‐Gangetic Plains

Sequestration of soil organic carbon (SOC) is an important strategy to improve soil quality and to mitigate climate change. To investigate changes in SOC under conservation agriculture (CA), we measured SOC concentrations after seven years of rice (Oryza sativa L.)–wheat (Triticum aestivum L.) rotations in the eastern Indo‐Gangetic Plains (IGP) of India under various combinations of tillage and crop establishment methods. The six treatments were as follows: conventional till transplanted rice followed by conventional till wheat (CTR‐CTW), CTR followed by zero‐till wheat (CTR‐ZTW), ZT direct‐seeded rice followed by CTW (ZTDSR‐CTW), ZTDSR followed by ZT wheat both on permanent raised beds with residue (PBDSR‐PBW+R), and ZTDSR followed by ZTW both with (ZTDSR‐ZTW+R) and without residues (ZTDSR‐ZTW). We hypothesized that CA systems (i.e. ZT with residue retention) would sequester more carbon (C) than CT. After seven years, ZTDSR‐ZTW+R and PBDSR‐PBW+R increased SOC at 0–0.6 m depth by 4.7 and 3.0 t C/ha, respectively, whereas the CTR‐CTW system resulted in a decrease in SOC of 0.9 t C/ha. Over the same soil depth, ZT without residue retention (ZTDSR‐ZTW) only increased SOC by 1.1 t C/ha. There was no increase in SOC where ZT in either rice or wheat was followed by CT in the next crop (i.e. CTR‐ZTW and ZTDSR‐CTW), most likely because the benefit of ZT is lost when followed by tillage. Tillage and crop establishment methods had no significant effect on the SOC stock below the 0.15‐m soil layer. Over the seven years, the total carbon input from above‐ground residues was ca. 14.5 t/ha in ZTDSR‐ZTW+R and PBDSR‐PBW+R, almost sixfold greater than in the other systems. Our findings suggest that the increased biomass production achieved through a combination of ZT and partial residue retention offers an opportunity to increase SOC whilst allowing residues to be used for other purposes

Climate Change and Agriculture: Adaptation Strategies and Mitigation Opportunities for Food Security in South Asia and Latin America

During the past two centuries, the world has witnessed a remarkable increase in the atmospheric concentrations of the greenhouse gases (GHGs), namely carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as a result of human activities after 1750 (preindustrial era). During 1750 the concentrations for these gases were 280 ppm, 715 ppb, and 270 ppb, respectively which increased to 379 ppm, 1774 ppb, and 319 ppb, respectively in 2005. It showed an increase of 0.23, 0.96, and 0.12% annually. The same has further increased to 385 ppm, 1797 ppb, and 322 ppb, respectively in 2008 representing 1.6, 1.2, and 0.9% increase, respectively from 2005 levels at an annual increase of 0.53, 0.43, and 0.31%, annually. Increase in atmospheric CO2 promotes growth and productivity of plants with C3 photosynthetic pathway but the increase in temperature, on the other hand, can reduce crop duration, increase crop respiration rates, affect the survival and distribution of pest populations, and may hasten nutrient mineralization in soils, decrease fertilizer-use efficiency, and increase evapotranspiration. The water resources which are already scarce may come under enhanced stress. Thus, the impact of climate change is likely to have a significant influence on agriculture and eventually on the food security and livelihoods of large sections of the urban and rural populations globally. The developing countries, particularly in South Asia and Latin America, with diverse agroclimatic regions, challenging geographies, growing economies, diverse agricultural production systems, and farm typologies are more vulnerable to the effect of climate change due to heavy dependence on agriculture for livelihood. These regions also are demonstrating poor coping mechanisms to adapt to these challenges, and as a result there is evidence of negative impacts on productivity of wheat, rice, and other crops to varying extent depending on agroecologies. Upscaling of modern technologies such as conservation and climate smart agriculture, judicious utilization of available water for agriculture through microirrigation and water saving technologies, developing multiple stress-tolerant crop cultivars and biotypes through biotechnological tools, restoration of degraded soils and waters, promoting carbon sequestration through alternate production technologies and land use, and conservation of biodiversity must be promoted at regional and country level to ensure durable food and nutritional security. Reliable early warning system of environmental changes, their spatial and temporal magnitude, coupled with policies to support the diffusion of this information, can help interpret these forecasts in terms of their agronomic and economic implications for the benefit of farmers and to provide agriculture-dependent industries and policymakers with more informed options to support farmers. These countries need to formulate both short-term and long-term policies for improvement, sustenance, and protection of natural resources. There is an urgent need for capacity building through international collaboration in order to develop databases and analysis systems for efficient weather forecasting as well as preparing contingency plans for vulnerable areas. The objectives of this paper are to summarize the available information on adaptation strategies and the mitigation options for climate change to meet the food security in South Asia and Latin America

Long-Term Conservation Agriculture and Intensified Cropping Systems: Effects on Growth, Yield, Water, and Energy-use Efficiency of Maize in Northwestern India

Conservation agriculture (CA)-based best-bet crop management practices may increase crop and water productivity, while conserving and sustaining natural resources. We evaluated the performance of rainy season maize during 2014 under an ongoing long-term trial (established in 2008) with three tillage practices, i.e., permanent bed (PB), zero tillage (ZT), and conventional tillage (CT) as main plots, and four intensified maize-based cropping systems, i.e., maize-wheat-mungbean, maize-chickpea-Sesbania (MCS), maize-mustard-mungbean, and maize-maize-Sesbania) as subplot treatments. In the seventh rainy season of the experiment, maize growth parameters, yield attributes, yield, and water- and energy-use efficiency were highest at fixed plots under ZT. Maize growth parameters were significantly (P < 0.05) superior under ZT and PB compared with CT. Maize yield attributes, including cobs per m2 (7.8), cob length (0.183 m), grain rows per cob (13.8), and grains per row (35.6), were significantly higher under ZT than CT; however, no significant effect of cropping systems was found on maize growth and yield attributes. Zero tillage exhibited the highest maize productivity (4 589 kg ha−1). However, among the cropping systems, MCS exhibited the highest maize productivity (4 582 kg ha−1). In maize, water use was reduced by 80.2–120.9 mm ha−1 under ZT and PB compared with CT, which ultimately enhanced the economic water-use efficiency by 42.0% and 36.6%, respectively. The ZT and PB showed a 3.5%–31.8% increase in soil organic carbon (SOC) at different soil depths (0–0.45 m), and a 32.3%–39.9% increase in energy productivity compared with CT. Overall, our results showed that CA-based ZT and PB practices coupled with diversified maize-based cropping systems effectively enhanced maize yield and SOC, as well as water- and energy-use efficiency, in northwestern India

Agronomic improvements can make future cereal systems in South Asia far more productive and result in a lower environmental footprint

South Asian countries will have to double their food production by 2050 while using resources more efficiently and minimizing environmental problems. Transformative management approaches and technology solutions will be required in the major grain-producing areas that provide the basis for future food and nutrition security. This study was conducted in four locations representing major food production systems of densely populated regions of South Asia. Novel production-scale research platforms were established to assess and optimize three futuristic cropping systems and management scenarios (S2, S3, S4) in comparison with current management (S1). With best agronomic management practices (BMPs), including conservation agriculture (CA) and cropping system diversification, the productivity of rice- and wheat-based cropping systems of South Asia increased substantially, whereas the global warming potential intensity (GWPi) decreased. Positive economic returns and less use of water, labor, nitrogen, and fossil fuel energy per unit food produced were achieved. In comparison with S1, S4, in which BMPs, CA and crop diversification were implemented in the most integrated manner, achieved 54% higher grain energy yield with a 104% increase in economic returns, 35% lower total water input, and a 43% lower GWPi. Conservation agriculture practices were most suitable for intensifying as well as diversifying wheat–rice rotations, but less so for rice–rice systems. This finding also highlights the need for characterizing areas suitable for CA and subsequent technology targeting. A comprehensive baseline dataset generated in this study will allow the prediction of extending benefits to a larger scale