Soil Chemical Analysis

Climate change 2014 - Synthesis Report

Ozone pollution in China: A review of concentrations, meteorological influences, chemical precursors, and effects

Climate change and global warming are of great concern to agriculture worldwide and are among the most discussed issues in today’s society. Climate parameters such as increased temperatures, rising atmospheric CO2 levels, and changing precipitation patterns have significant impacts on agricultural production and on agricultural insect pests. Changes in climate can affect insect pests in several ways. They can result in an expansion of their geographic distribution, increased survival during overwintering, increased number of generations, altered synchrony between plants and pests, altered interspecific interaction, increased risk of invasion by migratory pests, increased incidence of insect-transmitted plant diseases, and reduced effectiveness of biological control, especially natural enemies. As a result, there is a serious risk of crop economic losses, as well as a challenge to human food security. As a major driver of pest population dynamics, climate change will require adaptive management strategies to deal with the changing status of pests. Several priorities can be identified for future research on the effects of climatic changes on agricultural insect pests. These include modified integrated pest management tactics, monitoring climate and pest populations, and the use of modelling prediction tools.

The Impact of Climate Change on Agricultural Insect Pests.

Free-air CO2 enrichment (FACE) allows open-air elevation of [CO2] without altering the microclimate. Its scale uniquely supports simultaneous study from physiology and yield to soil processes and disease. In 2005 we summarized results of then 28 published observations by meta-analysis. Subsequent studies have combined FACE with temperature, drought, ozone, and nitrogen treatments. Here, we summarize the results of now almost 250 observations, spanning 14 sites and five continents. Across 186 independent studies of 18 C3 crops, elevation of [CO2] by ca. 200 ppm caused a ca. 18% increase in yield under non-stress conditions. Legumes and root crops showed a greater increase and cereals less. Nitrogen deficiency reduced the average increase to 10%, as did warming by ca. 2°C. Two conclusions of the 2005 analysis were that C4 crops would not be more productive in elevated [CO2], except under drought, and that yield responses of C3 crops were diminished by nitrogen deficiency and wet conditions. Both stand the test of time. Further studies of maize and sorghum showed no yield increase, except in drought, while soybean productivity was negatively affected by early growing season wet conditions. Subsequent study showed reduced levels of nutrients, notably Zn and Fe in most crops, and lower nitrogen and protein in the seeds of non-leguminous crops. Testing across crop germplasm revealed sufficient variation to maintain nutrient content under rising [CO2]. A strong correlation of yield response under elevated [CO2] to genetic yield potential in both rice and soybean was observed. Rice cultivars with the highest yield potential showed a 35% yield increase in elevated [CO2] compared to an average of 14%. Future FACE experiments have the potential to develop cultivars and management strategies for co-promoting sustainability and productivity under future elevated [CO2].

30 years of free-air carbon dioxide enrichment (FACE): What have we learned about future crop productivity and its potential for adaptation?

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

Growth, yield and quality of maize with elevated atmospheric carbon dioxide and temperature in north–west India

Climate change impact, adaptation and mitigation in agriculture: methodology for assessment and applications

Sensitivity to tropospheric ozone is highly variable in cultivars of different plant species. Wheat, an important cereal crop, has been found to be sensitive to elevated ozone levels leading to differences in grain yields. The objective of this study was to compare the effects of elevated tropospheric ozone on growth, yield and nutritional quality of two species of wheat, Triticum aestivum (PBW 343) and Triticum durum (HD 2936), which are tropical wheat cultivars commonly grown in northern India. Experiments were conducted growing winter wheat (rabi season) under elevated tropospheric ozone in northern India for two years in open-top chambers (OTCs) under charcoal-filtered air (CF), non-filtered air (NF), open air (OA) and elevated ozone (EO) concentration (NF + 25-35 ppb O3). There were different species responses to EO, with the modern aestivum wheat cultivar being more sensitive than durum wheat. The declines in all growth and yield parameters were greater in T. aestivum than T. durum in both the years. On average there was a 7% greater reduction in the photosynthetic rate and stomatal conductance in T. aestivum as compared to T. durum under EO at the flowering stage, and a 6% more reduction in leaf chlorophyll was observed on T. aestivum as compared to T. durum. Exposure to elevated O3 caused a decrease in the number of leaves and leaf area index, rubisco enzyme activity and chlorophyll in both the species. More reductions in grain yield were observed in T. aestivum (15 and 19%) as compared to T. durum (9 and 13%) under EO in the two years, respectively. Filtration of air significantly increased all growth and yield parameters in both species of wheat.

/pdf/impact-of-elevated-ozone-on-growth-yield-and-nutritional-58lzv459be.pdf

Impact of Elevated Ozone on Growth, Yield and Nutritional Quality of Two Wheat Species in Northern India

This review presents tropospheric ozone (O3), an air pollutant affecting agriculture by reducing crop yield and deteriorating quality of produce. O3 enters leaves through stomata and diffuses within the apoplast, producing many oxidizing compounds and affecting various physiological and biochemical processes, crop growth and yield. O3 affects above and below ground carbon allocation and its dynamics, N cycling, microbial content and emission of greenhouse gases (GHG) from soil. This review focuses on the impact of O3 on crop growth with special emphasis on productivity in Asian region, methods for evaluating O3 responses in field, amelioration of O3 induced injury and providing dose-response functions for economic assessments.

http://nopr.niscair.res.in/bitstream/123456789/13486/1/JSIR%2071%282%29%2097-112.pdf

S. D. Singh

Papers

Impact of temperature on phenology and pollen sterility of wheat varieties

Growth, yield and quality of maize with elevated atmospheric carbon dioxide and temperature in north–west India

Climate change impact, adaptation and mitigation in agriculture: methodology for assessment and applications

Impact of Elevated Ozone on Growth, Yield and Nutritional Quality of Two Wheat Species in Northern India

Impact of tropospheric ozone on crop growth and productivity - a review