Preface   Nutrient use efficiency is a measure of how efficiently plants use the available mineral nutrients to produce economic produce. Improving nutrient use efficiency is very much essential under current scenario besides an understanding of the nutrient dynamics in soil-plant system.”Enhancing nutrient use efficiency: Concepts, methods, and management interventions” is a comprehensive book which has a compilation of topics related to enhancement of nutrient use efficiency of various crops and cropping systems. Although it depends on the ability to plants to take up the nutrients from the soil, management practices have a key role to intervene the use efficiency. This book has 27 chapters written by eminent researchers in the field and addresses multifaceted approaches to enhance the nutrient use efficiency. Improving nutrient use efficiency is a prerequisite to reducing production costs in the wake of escalating cost of agricultural inputs in farming besides minimizing environmental contamination. Soil physical management is the foremost strategy to enhance the nutrient use efficiency. Hand held devices are popular among the farmers for nitrogen management in rice in several parts of the country, besides slow release nitrogenous fertilizers. Experiences from Long term fertilizer experiments and soil test crop response correlation are of immense use to understand the nutrient dynamics in soil and in turn designing practices for higher use efficiency. Besides describing the concepts and methods of nutrient use efficiency, management practices for dry land crops and cropping systems, cereal based cropping systems, rainfed pulses based cropping systems, soybean based cropping systems, sugarcane based cropping systems, cotton based cropping systems, tobacoo and oil seed based cropping systems, rapeseed-mustard based cropping systems and spices based cropping systems are also dealt in this book and would serve as a resource guide for enhancing nutrient use efficiency in various crops and cropping systems. We place on record our sincere thanks to all the authors for providing updated information in the field of nutrient use efficiency in various crops and cropping systems. We wish to express our deep sense of gratitude to Dr Trilochan Mohapatra, DG (ICAR) and Secretary (DARE) for his constant encouragement to us. We thankfully acknowledge Dr SK Chaudhari, ADG (Soil and water Management) and Dr S Baskar, ADG (Agronomy, Agroforestry and Climate change) for the continued support to us. We do hope, this book will be of immense use to scientists, farmers, students and policymakers for enhancing nutrient use efficiency in various crops and cropping systems.

Introduction To meet the food needs of the burgeoning population, India will need to produce 300 million tonnes of food grains by 2020. At present more than 75% of the total food grains produced in the country are of rice and wheat. Use of nitrogenous fertilizers has contributed much to the remarkable increase in production of rice and wheat in India that has occurred during the past three decades. During the last half-decade or so while fertilizer N consumption is touching new heights, the production of both rice and wheat is showing a trend of plateauing.

Introduction It is well-known that soil testing is agronomically sound, beneficial and environmentally responsive tool for monitoring the nutrient as well as pollutant status of soils, and also for making precise fertilizer recommendations for various crops and cropping sequences. Soil testing with associated plant and water analysis is the only tool known which helps to control soil fertility. Nutrient supplying power of soils, crop responses to added nutrients and fertilizer and amendment needs can safely be assessed through sound soil testing programme. Monitoring of soil fertility, against depletion and accumulation of certain elements in toxic proportions over time, is also possible through appropriate soil tests. This also helps to economize on cost of fertilizers and also in increasing fertilizer use efficiency.

Introduction The Indian agriculture is very complex and carrying out multi-functionalities of providing food, nutrition and ecological security besides employment and livelihood for over 700 million people. Indeed, India has made a marvelous achievement in attaining self-sufficiency in food grain production after the introduction of Green Revolution which eventually resulted in maintaining all-time high buffer stock in warehouses of our country. Such rosy picture in production trends turned to be bleak in the past few years.

Introduction “Non-monetary inputs are defined as those cultural operations which help to achieve high yield at no extra cost and whose cost does not change with the level of output”.   After the advent of green revolution, nutrient management has received the significant attention by farmer as well as researchers; as a result of which and coupled with the requirement for high yielding varieties, consumption of plant nutrient (N, P and K) increased tremendously. Variability was observed in fertilizer consumption between the states. 

Plant mineral nutrition is a sub branch of plant physiology which addresses issues on uptake of elements that plant needs to absorb from air or water or soil to grow and to live. Besides function of nutrient elements in plants, it also includes deficiency symptoms and how to address deficiency symptoms in a plant. Plant mineral nutrition and mechanism of uptake has two major aspects:

Introduction Nitrogen (N) fertilization assured centre stage for enhancing food production in developing countries especially after the introduction of high yielding and fertilizer responsive crop varieties. Almost half of the human population relies on N fertilizer for food production (Ladha et al., 2005), and about 56 percent of the N fertilizer is used for producing rice, maize, and wheat (IFA, 2002). It has contributed an estimated 40% to the increase in per capita food production over the past 50 years (Smil, 2002). However, excess use of chemical N fertilizer may negatively affect surface water, as well as groundwater, and the atmosphere (through leaching and runoff) through volatilization of N (Galloway et al., 2008).

Water and nutrients are the most important, and readily manageable, variables for producing a profitable crop. Efficient management of water and essential plant nutrients is imperative for achieving sustainable agriculture and maintaining necessary increase in food production to feed the burgeoning population while minimizing economic losses and environmental impacts. Technology here can play a catalytic role in striking a common ground between these environmental and economic goals. Recent advances in sensor technologies indicate that efficient nutrient management in crop fields can be attained through the application of Precision Agriculture (PA)-based geo-spatial technologies such as global positioning system, geographical information system, remote sensing,

With the introduction of high yielding varieties and use of high analysis fertilizer in intensified agriculture under irrigation condition resulted in green revolution in our country. But continuous use of chemical fertilizer in indiscriminate manner without assessing soil also had adverse effect on productivity and environment. Though use of high analysis fertilizer ensured the high production but also resulted in acceleration of mining of native sources of nutrient. This has led to appearance of hidden hunger of several other essential nutrients and sustainability of our agriculture has become venerable.

Introduction   The major challenges in 21st century are food security, environmental quality and soil health. Besides, shrinking land holdings and increasing cost of inputs in India merit adoption of scientific use of plant nutrient for higher crop productivity. The soil fertility and fertilizer use project initiated in 1953 following a study by Stewart in 1947 which was the first systematic attempt in India to relate the knowledge of the soils to the judicious use of chemical fertilizers. The soil testing programme was started in India during the year 1955-56 with the setting up of 16 soil testing laboratories under the Indo-US Operational Agreement for “Determination of Soil Fertility and Fertilizer Use”. In 1965, five of the existing laboratories were strengthened and nine new laboratories were established to serve the Intensive Agricultural District Programme (IADP) in selected districts.

Introduction Phosphorus (P) is a major nutrient in crop production, but is also a major constraint due to its low bioavailability in soils. It is 11th most abundant element on earth’s crust and a  vital component of DNA, RNA, ATP and photosynthetic system and catalyses a number of biochemical reactions from the beginning of seedling growth through to the formation of grain and maturity. Many factors influence soil P availability like type of parent material from which the soil is derived, degree of weathering and climatic conditions.

Introduction Increasing consciousness about conservation of environment as well as health hazards associated with agrochemicals and consumers’ preference to safe and hazard free food are the major factors that lead to the growing interest in environmental friendly forms of farming in the world. Organic agriculture is one such broad spectrum of production methods that are supportive to the environment. The basic requirement in organic farming is to increase input use efficiency at each stage of farm operation.

Indian agriculture has grown over past 50 years from subsistence type of farming to a market surplus one with the present food grain production above 250 million tones (Fig. 1) which was only 50 million tones in 1950. At the same time the country has struggled over the years to meet the fertilizer requirement. More than 50 per cent fertilizer consumption is imported.

Introduction Crop production system includes the components like soil, climate and plant (genetic) material. Within a particular genetic make up of the crop, productivity of the system is limited either by climatic factors, that is, radiation, temperature and rainfall (water), or by inherent edaphic environment that govern the root development and consequent uptake of water and nutrients. Where soils are cultivated over long periods, the edaphic conditions reach at its low levels. When water, nutrients and CO2 are plentiful, yield is determined by radiation and temperature regimes during the growing season. However, under actual field situations, the yields are limited by factors other than climate, which is water and nutrients. These are not only limited in amounts but also are becoming costlier every year. It is, therefore, important that available fertilizers be used efficiently.

Introduction Soil resource is as important as water for agriculture as it supplies nutrients to the plants and anchorage for stand and establishment. However, people least bother about its importance despite its role in food security and ecosystem services. Good quality soil is a prerequisite for sustainable crop production. The concept of conservation agriculture (CA) has emerged in the recent past wherein conventional practices are modified to reduce farming cost in addition to sustaining soil health. Improvement in the soil health is achieved by increasing soil organic carbon (SOC), aggregation, infiltration, and also reduction in soil erosion.

Introduction Soil is a complex system consisting of physical, chemical and biological components. These components dynamically interact making it functional to sustain life. All life forms rely on soil microbial processes for their survival. Microbial diversity in the soil is greater than the diversity of any other group of organisms existing in the earth. Microbes as inhabitant of soil are responsible for diverse metabolic functions that affect soil and plant health (Table 1).

Introduction Nano science is the study of the properties of structures of the size smaller than several hundreds of nano meter (nm). Nanotechnology consists in techniques for designing and manufacturing these structures as well as applications arising from these. The development of nanoscience and nanotechnology is in line with the trend towards miniaturisation. As nanoscience and nanotechnology developed, they make the barriers between traditional scientific and technological disciplines more permeable.

Introduction Fertilizers in India, are mostly applied either through broadcasting, foliar application or using seed cum fertilizer drills. With the introduction of micro irrigation systems, the application of fertilizers along with the irrigation water became promising and is gaining momentum. The goal of fertilizer application through irrigation is to maximize the uptake rate of fertilizers in order to minimize the losses.

Introduction Land serves as storage for water and nutrients for plants and other living organisms, but the land resources are limited. India has about 18% of world’s population and 15% of livestock population to be supported from only 2% geographical area and 1.5% of forest and pasture lands (Rao et al., 2015). The per capita availability of agricultural land has declined from 0.48 hectare in 1951 to 0.16 hectare in 1991 and is likely to decline further to 0.08 hectare in 2035. This decline in per capita land availability in the country is mostly on account of rising population (GOI, 2010). 

Introduction India has predominantly agrarian economy with just 2.5% of the world’s geographical area, but has about 17% of its population. India’s population has increased from 361 million in 1951 to 1270 million at present: a three and half-fold increase in a span of 63 years. By 2020, India will need about 294 million tonnes food grains (Kumar, 1998). However, only 259.29 m t was produced in 2011–12 (Directorate of Economics and Statistics, Ministry of Agriculture, 2012), implying that about 34 m t additional food grains have to be produced from the same or even lesser land area.

Introduction Out of the total cultivated area of 142 million hectares (M ha) in India during 2011–12, 100.2 M ha was under cereals (the word cereal derives from Ceres, the name of the Roman goddess of harvest and agriculture) and 24.8 M ha under pulses (splitting seed), the staple food grains in the country (Economic Survey 2013). There is very little scope of bringing additional area under food grains; on the contrary this may decline in future due to the land needed for civil amenities and industrial purposes.

Introduction India is the largest producer, importer and consumer of pulses in the world, accounting for 25 percent of the global production, 15 per cent trade and 27 per cent consumption, being an inseparable ingredient in the diet of the vast majority of population. Since time immemorial, pulses have been cultivated on marginal and sub-marginal lands, which are characterized by poor soil fertility and moisture stress, and consequently their yield potentials have not been realized. Further, more than 90 per cent areas under pulses are rainfed.

Introduction   Soybean (Glycine max L. Merril) is the world’s most important oil yielding legume which contributes 25% of the global edible oil, about two thirds of the world’s protein concentrate feeds for livestock, poultry and fish. India ranks fifth in the area and production in the world after USA, Brazil, Argentina and China. The contribution of India in the world soybean area is 10% but to total world soybean production is only 4% indicating the poor levels of productivity of the crop in India (1.1 t/ha) as compared to other courtiers (World average 2.2 t/ha) which is a major cause of concern.

Introduction   Sugarcane is an important cash crop of India. Since 1930-31 the area of sugarcane in the country has increased by about 4.3 times and production by about 9.8 times because of the rise in productivity of sugarcane by about 2.28 times, however, during the last decade there is no perceptible increase in productivity of sugarcane in the country. The domestic demand of sugar is around 22-23 million tonnes annually whereas the production of sugar in India is about 26 million tonnes annually. Data on nitrogen use efficiency of sugarcane from 1998-99 to 2013-14 in India is depicted in Fig. 1 and 2 show a decreasing trend (Anonymous, 2015). However, the escalating price of fertilizers in the market has become a cause of concern to sustain the productivity of the crop.

Introduction   Cotton belongs to the genus Gossypium, family Malvaceae. Of the 50 species, only four are cultivated, namely, G. arboreum, G. herbaceum, G. hirsutum and G. barbadense. The G. arboreum and G. herbaceum are popularly known as the desi cottons. The G. hirsutum and G. barbadense evolved in the new world and are known as American or Upland (G. hirsutum) and Egyptian or Pima (G. barbadense) cottons. India is the only country in the world where all the four cultivated species of cotton are grown on a commercial scale besides hybrids (both inter and intra specific) in three distinct agro-ecological regions and wide range of soil types.

Introduction   In India, most of the agricultural soils are deficient in one or more of the essential plant nutrients required for raising healthy crops and harvesting potential yield. Acidity, alkalinity, salinity, anthropogenic processes, nature of farming, and erosion are the main factors that can lead to soil degradation either alone or in combination of more than one factors.

Introduction   Poor nutrient use efficiency result in loss of nearly 0.8 million tonnes of nitrogen, 1.8 million tonnes of phosphorus and 26.3 million tonnes of potassium annually. Soil health is further deteriorated by imbalanced application of nutrients and excessive mining of micronutrients, leading to deficiency of macro- and micronutrients in the soils (ICAR Vision 2030). Due to the imbalanced use of plant nutrients, mining of nutrients is considered as the main cause for decline in crop yield and crop response ratio.

Introduction Spice – definition and uses SPICES are aromatic or pungent vegetable substances, used as whole, broken, or ground form, whose function in food is seasoning rather than nutrition and commonly used as a condiment. It may be a dried seed, fruit, root, rhizome, bark or vegetative substance or flower bud. American Spice Trade Association (ASTA) defines spices as “any dried plant product used primarily for seasoning purposes”. Included are tropical aromatics (pepper, cinnamon, cloves, etc.), leafy herbs (basil, oregano, marjoram, etc.), spice seeds (sesame, poppy, mustard, etc.) and dehydrated vegetables (onions, garlic, etc.). Many spices have other uses like food preservation, medicine, religious rituals, cosmetics, and perfumery or as vegetables.

Colour Figures Chapter 2: Soil Testing: Basic Tool for Enhancing the Nutrient Use Efficiency