Terrestrial net primary production (NPP) quantifies the amount of atmospheric carbon fixed by plants and accumulated as biomass. Previous studies have shown that climate constraints were relaxing with increasing temperature and solar radiation, allowing an upward trend in NPP from 1982 through 1999. The past decade (2000 to 2009) has been the warmest since instrumental measurements began, which could imply continued increases in NPP; however, our estimates suggest a reduction in the global NPP of 0.55 petagrams of carbon. Large-scale droughts have reduced regional NPP, and a drying trend in the Southern Hemisphere has decreased NPP in that area, counteracting the increased NPP over the Northern Hemisphere. A continued decline in NPP would not only weaken the terrestrial carbon sink, but it would also intensify future competition between food demand and proposed biofuel production.

Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009

Agriculture and climate change are internally correlated with each other in various aspects, as climate change is the main cause of biotic and abiotic stresses, which have adverse effects on the agriculture of a region. The land and its agriculture are being affected by climate changes in different ways, e.g., variations in annual rainfall, average temperature, heat waves, modifications in weeds, pests or microbes, global change of atmospheric CO2 or ozone level, and fluctuations in sea level. The threat of varying global climate has greatly driven the attention of scientists, as these variations are imparting negative impact on global crop production and compromising food security worldwide. According to some predicted reports, agriculture is considered the most endangered activity adversely affected by climate changes. To date, food security and ecosystem resilience are the most concerning subjects worldwide. Climate-smart agriculture is the only way to lower the negative impact of climate variations on crop adaptation, before it might affect global crop production drastically. In this review paper, we summarize the causes of climate change, stresses produced due to climate change, impacts on crops, modern breeding technologies, and biotechnological strategies to cope with climate change, in order to develop climate resilient crops. Revolutions in genetic engineering techniques can also aid in overcoming food security issues against extreme environmental conditions, by producing transgenic plants.

Impact of Climate Change on Crops Adaptation and Strategies to Tackle Its Outcome: A Review.

Drought has been a major cause of agricultural disaster, yet how it affects the vulnerability of maize and wheat production in combination with several co-varying factors (i.e., phenological phases, agro-climatic regions, soil texture) remains unclear. Using a data synthesis approach, this study aims to better characterize the effects of those co-varying factors with drought and to provide critical information on minimizing yield loss. We collected data from peer-reviewed publications between 1980 and 2015 which examined maize and wheat yield responses to drought using field experiments. We performed unweighted analysis using the log response ratio to calculate the bootstrapped confidence limits of yield responses and calculated drought sensitivities with regards to those co-varying factors. Our results showed that yield reduction varied with species, with wheat having lower yield reduction (20.6%) compared to maize (39.3%) at approximately 40% water reduction. Maize was also more sensitive to drought than wheat, particularly during reproductive phase and equally sensitive in the dryland and non-dryland regions. While no yield difference was observed among regions or different soil texture, wheat cultivation in the dryland was more prone to yield loss than in the non-dryland region. Informed by these results, we discuss potential causes and possible approaches that may minimize drought impacts.

Global Synthesis of Drought Effects on Maize and Wheat Production

In the current scenario, it is an urgent requirement to satisfy the nutritional demands of the rapidly growing global population. Using conventional farming, nearly one-third of the crops get damaged mainly due to pest infestation, microbial attacks, natural disasters, poor soil quality, and lesser nutrient availability. More innovative technologies are immediately required to overcome these issues. In this regard, nanotechnology has contributed to the agrotechnological revolution that has imminent potential to reform the resilient agricultural system, while promising food security. Therefore, nanoparticles are becoming a new-age material to transform modern agricultural practices. The variety of nanoparticles-based formulations, including, nano-sized pesticides, herbicides, fungicides, fertilizers, and sensors, have been widely investigated for plant health management and soil improvement. In-depth understanding of plant and nanomaterial interactions opens new avenues towards improving crop practices through increased properties like disease resistance, crop yield, and nutrient utilization. In this review, we highlight the critical points to address the current nanotechnology-based agricultural research that could benefit productivity and food security in future.

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Nanoparticle-Based Sustainable Agriculture and Food Science: Recent Advances and Future Outlook

This article reviews recent literature on drought of the last millennium, followed by an update on global aridity changes from 1950 to 2008. Projected future aridity is presented based on recent studies and our analysis of model simulations. Dry periods lasting for years to decades have occurred many times during the last millennium over, for example, North America, West Africa, and East Asia. These droughts were likely triggered by anomalous tropical sea surface temperatures (SSTs), with La Ni˜ na-like SST anomalies leading to drought in North America, and El-Ni˜ no-like SSTs causing drought in East China. Over Africa, the southward shift of the warmest SSTs in the Atlantic and warming in the Indian Ocean are responsible for the recent Sahel droughts. Local feedbacks may enhance and prolong drought. Global aridity has increased substantially since the 1970s due to recent drying over Africa, southern Europe, East and South Asia, and eastern Australia. Although El Ni˜ no-Southern Oscillation (ENSO), tropical Atlantic SSTs, and Asian monsoons have played a large role in the recent drying, recent warming has increased atmospheric moisture demand and likely altered atmospheric circulation patterns, both contributing to the drying. Climate models project increased aridity in the 21 st century over most of Africa, southern Europe and the Middle East, most of the Americas, Australia, and Southeast Asia. Regions like the United States have avoided prolonged droughts during the last 50 years due to natural climate variations, but might see persistent droughts in the next 20–50 years. Future efforts to predict drought will depend on models’ ability to predict tropical SSTs. 2010 JohnWiley &Sons,Ltd.WIREs Clim Change2010 DOI:10.1002/wcc.81

Drought under Global Warming: A Review

Agro-botanical response of forage sorghum-soybean intercropping systems under atypical spatio-temporal pattern.

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Revamping soil quality and correlation studies for yield and yield attributes in sorghum-legumes intercropping systems

Forages are the most palatable animal feed resource and highly relished by dairy animals. Forage maize is a high yielder of green forage but confronts under nourishment. Plant nutrition is one of the most important and vital factor which determines forage yield and plays an important role in ensuring considerably high forage yield for ruminants. Nitrogen and phosphorous are the most important plant nutrients which affect forage yield, as well as quality attributes of green forage. As inorganic fertilizers prices are skyrocketing with each passing year, small farmers in developing countries like Pakistan and India can ill-afford to supply required plant nutrients particularly nitrogen and phosphorous through inorganic means at appropriate time and in balanced quantities and resultantly forage yield suffers a serious setback. An optimum combination of organic, as well as inorganic fertilizers has the potential to increase the forage yield of maize along with quality parameters particularly protein content. Plant nutrition management by combining farm yard manure and poultry manure with inorganic fertilizers not only ensures increased forage yield but forage quality is also improved. However, need of hour is to make rigorous and in-depth investigations to find out the most appropriate combinations of inorganic fertilizers and organic sources to ensure the sustainability of agriculture and to increase the productivity of dairy animals along with increasing the income of cash striving small land holders as a part of poverty alleviation strategies in developing countries.

Overviewing Forage Maize Yield and Quality Attributes Enhancement with Plant Nutrition Management

Changing climates and frequent spells of drought have increased the risk of crop failure, especially in arid and semi-arid regions, thus multiplying the vulnerability of food-insecure populations. The exogenous application of potassium (K) can potentially ameliorate the adverse effects of drought in maize by maintaining cell osmotic potential and turgidity, provided its optimum doses are applied. The present experiment comprised two maize cultivars, viz. Islamabad Gold (drought tolerant) and Azam (drought susceptible), grown under well-watered (80% water-holding capacity (WHC)), mild drought (60% WHC) and severe drought (40% WHC) conditions. Different doses of K, viz. 0%, 1% and 2%, were also tested to screen out the most superior concentration. Drought stress markedly reduced root and shoot lengths (25% and 16%, respectively) along with their dry weights (20% and 10%, respectively). Moreover, a substantial reduction in leaf relative water content (RWC) (24%), stomatal conductance, transpiration and photosynthesis rates, chlorophyll pigments a, b and total chlorophyll contents (31%) were recorded, compared with well-watered conditions. However, foliar application of K2SO4 at 2% concentration outperformed other doses by improving growth attributes, RWC (10%), total chlorophyll (9%) and proline (12%) under severe drought conditions. Our findings confirmed the effectiveness of foliage-applied K2SO4 in ameliorating drought effects in rainfed maize; however, more doses and sources of K could be tested for developing it as a potent source to cope with water stress.

Foliar Potassium Sulfate Application Improved Photosynthetic Characteristics, Water Relations and Seedling Growth of Drought-Stressed Maize

Fertilizers are artificial substances which contain chemical elements that are required by plants for robust growth and productivity of crops. Fertilizers are applied to soils to increase the soil fertility which is the capacity of soil to supply essentail nutrients to plants for their growth and development. Modern chemical fertilizers include one or more elements, but the most important elements in plant nutrition are nitrogen, phosphorus and potassium which are called primary nutrients. Of primary nutrients, nitrogen is considered to be the most important one and is required by the crops in the greatest quantities. Nitrogenous fertilizers mostly used by local faarmers include urea (46% N), calcium ammonium nitrate CAN (26% N) and ammonium sulphate (21% N + 24% sulphur). Phosphatic fertilizers include single super phosphate (18% P O + 12% sulphur), 25 Triple superphosphate (46% P O + 1.5% sulphur), Di-ammonium phosphate (46% P O + 18% N) and 25 25 Mono-ammonium phosphate (52% P O + 11% N + 2% sulphur). Potassium is supplied to plants as K O. 25 2 Sulphate of potash (50% K O + 18% sulphur) and Muriate of potash (60% K O) are two important potassic 22

Muhammad Aamir Iqbal

Papers

Agro-botanical response of forage sorghum-soybean intercropping systems under atypical spatio-temporal pattern.

Revamping soil quality and correlation studies for yield and yield attributes in sorghum-legumes intercropping systems

Overviewing Forage Maize Yield and Quality Attributes Enhancement with Plant Nutrition Management

Foliar Potassium Sulfate Application Improved Photosynthetic Characteristics, Water Relations and Seedling Growth of Drought-Stressed Maize

A preliminary study on plant nutrients production as combined fertilizers, consumption patterns and future prospects for Pakistan.