Soil Chemical Analysis

Climate change 2014 - Synthesis Report

https://hal.archives-ouvertes.fr/hal-01480573/document

Soil carbon 4 per mille

Tomorrow’s agriculture, challenged by increasing global demand for food, scarcity of arable lands, and resources alongside multiple environment pressures, needs to be managed smartly through sustainable and eco-efficient approaches. Modern agriculture has to be more productive, sustainable and environmentally friendly. While macronutrients such as nitrogen (N), phosphorus (P), potassium (K) and sulfur (S) supplied by mineral fertilizers are vital to crop production, agriculturally beneficial microorganisms may also contribute directly (i.e. biological N2 fixation, P solubilization, phytohormone production, etc.) or indirectly (i.e. antimicrobial compounds biosynthesis, elicitation of induced systemic resistance, etc.) to crop improvement and fertilizers efficiency. Microbial-based bioformulations that increase plant performance are greatly needed, and in particular bioformulations that exhibit complementary and synergistic effects with mineral fertilization. Such an integrated soil fertility management strategy has been demonstrated through several controlled and non-controlled experiments, but more efforts have to be made in order to thoroughly understand the multiple functions of beneficial microbes’ functions within the soil microbial community itself and in interaction with plants and mineral resources. In fact, the combined usage of microbial (i.e. beneficial microorganisms: N2-fixing (NF), P-solubilizing and P mobilizing, etc.) and mineral resources is an emerging research area that aims to design and develop efficient microbial formulations which are highly compatible with mineral inputs, with positive impacts on both crops and environment. This novel approach is likely to be of a global interest, especially in most N- and P-deficient agro-ecosystems. In this review, we report on the importance of NF bacteria and P solubilizing/mobilizing microbes as well as their interactions with mineral P fertilization in improving crop productivity and fertilizers efficiency. In addition, we shed light on the interactive and synergistic effects that may occur within multi-trophic interactions involving those two microbial groups and positive consequences on plant mineral uptake, crop productivity and resiliency to environmental constraints. Improving use of mineral nutrients is a must to securing higher yield and productivity in a sustainable manner, therefore continuously designing, developing and testing innovative integrated plant nutrient management systems based on relevant biological resources (crops and microorganisms) is highly required.

/pdf/soil-microbial-resources-for-improving-fertilizers-bxffll7j90.pdf

Soil Microbial Resources for Improving Fertilizers Efficiency in an Integrated Plant Nutrient Management System

Drought (water deficits) and heat (high temperatures) stress are the prime abiotic constraints, under the current and climate change scenario in future. Any further increase in the occurrence, and extremity of these stresses, either individually or in combination, would severely reduce the crop productivity and food security, globally. Although, they obstruct productivity at all crop growth stages, the extent of damage at reproductive phase of crop growth, mainly the seed filling phase, is critical and causes considerable yield losses. Drought and heat stress substantially affect the seed yields by reducing seed size and number, eventually affecting the commercial trait ‘100 seed weight’ and seed quality. Seed filling is influenced by various metabolic processes occurring in the leaves, especially production and translocation of photoassimilates, importing precursors for biosynthesis of seed reserves, minerals and other functional constituents. These processes are highly sensitive to drought and heat, due to involvement of array of diverse enzymes and transporters, located in the leaves and seeds. We highlight here the findings in various food crops showing how their seed composition is drastically impacted at various cellular levels due to drought and heat stresses, applied separately, or in combination. The combined stresses are extremely detrimental for seed yield and its quality, and thus need more attention. Understanding the precise target sites regulating seed filling events in leaves and seeds, and how they are affected by abiotic stresses, is imperative to enhance the seed quality. It is vital to know the physiological, biochemical and genetic mechanisms, which govern the various seed filling events under stress environments, to devise strategies to improve stress tolerance. Converging modern advances in physiology, biochemistry and biotechnology, especially the “omics” technologies might provide a strong impetus to research on this aspect. Such application, along with effective agronomic management system would pave the way in developing crop genotypes/varieties with improved productivity under drought and/or heat stresses.

/pdf/drought-or-and-heat-stress-effects-on-seed-filling-in-food-45nidd1zbx.pdf

Drought or/and heat-stress effects on seed filling in food crops: Impacts on functional biochemistry, seed yields, and nutritional quality

Assessing the vulnerability of Indian mustard to climate change

Potential and cost of carbon sequestration in Indian agriculture: Estimates from long-term field experiments

Low temperature during reproductive stage of spring wheat causes sterility of pollen grains and reduced yield. Field experiment was conducted during the winter season in the farm of Indian Agricultural Research Institute with wheat crop to study the effect of temperature on phenology and pollen sterility of spring wheat crop. Lower mean temperature during the crop growth period led to enhanced the crop growth period in both aestivum and durum varieties of wheat crop. Results showed that in early sowing treatment pollen sterility percentage was very high (46.1%) in HD 2851 variety. This in turn led to decreased pollen germination and lesser yield in wheat crop. Pollen germination was maximum between mean temperatures of 18-20C, while at lower temperatures germination of pollen grains got reduced in all wheat varieties. A good positive correlation was obtained between pollen germination percentage and yield (R 2 =0.65) of wheat crop. Data from this experiment indicate that low temperature during reproductive phase could limit wheat yield by affecting its phenology and fertility of pollen grains. Adaptation measures need to be developed for reducing yield loss of wheat in areas experiencing very low temperature during anthesis stage.

/pdf/impact-of-temperature-on-phenology-and-pollen-sterility-of-2ko1brgzwy.pdf

Impact of temperature on phenology and pollen sterility of wheat varieties

Impact of terminal heat stress on wheat yield in India and options for adaptation

Increasing temperature is likely to affect productivity of wheat and chickpea crop. A field experiment was conducted for two consecutive years with wheat and chickpea crop raised inside the temperature gradient tunnel (TGT). Results showed that high temperature reduced crop growth duration in both the crops. Days to 50 % flowering reduced by 4–5 days in wheat with 1.8–2.9 °C increase in temperature. Photosynthesis rate, stomatal conductance and leaf area index reduced with the rise in temperature. High temperature inside the TGT caused reduction in both biomass and grain yield of wheat crop in both the years and the reductions in yield per degree temperature rise was 10.4–10.5 % in wheat crop. Number of spikes per plant, number of grains per spike, 1,000 seed weight was also affected with increased temperature. In case of chickpea crop, yield declined with the increase in temperature during the 2008–2009 year and the decline per degree temperature rise was 6.8 %. During the year 2007–2008, 1.7 °C increase in temperature showed improvement in biomass and grain yield in chickpea. Low air temperature during the crop growth period in 2007–2008 could be responsible for increased growth of chickpea under high temperature. This suggests that rise in temperature in future climatic change scenario will adversely affect wheat and chickpea crop but the response will be crop and region specific depending upon the existing climate conditions.

https://www.researchgate.net/profile/Bidisha_Chakrabarti/publication/257811014_Growth_and_yield_response_of_wheat_and_chickpea_crops_under_high_temperature/links/00b49528457797dab7000000.pdf

B. Chakrabarti

Papers

Assessing the vulnerability of Indian mustard to climate change

Potential and cost of carbon sequestration in Indian agriculture: Estimates from long-term field experiments

Impact of temperature on phenology and pollen sterility of wheat varieties

Impact of terminal heat stress on wheat yield in India and options for adaptation

Growth and yield response of wheat and chickpea crops under high temperature