eChapters

Introduction

Remote sensing is the science and art of obtaining information about an object, area or phenomenon through an analysis of the data acquired by a device which is not in contact with the object, area or phenomenon under investigation. The definition of remote sensing is restricted to mean the process of acquiring information about any object without physically contacting it in anyway regardless of whether the observer is immediately adjacent to the object or millions of miles away. It is further required that such sensing may be achieved in the absence of any matter in the intervening space between the object and the observer. Consequently, the information about the object, area or any phenomenon must be available in a form that can be impressed on a carrier vacuum.

Introduction

Fast and efficient dissemination of suitable technological information from the Agricultural Research System to the Farmers in the field and reporting of farmers’ feedback to the research system is one of the critical inputs in Transfer of Technology. Today India is at the verge of technology revolution with immense number of agriculture, home science and livestock technologies developed by the research institutes to enhance the agriculture and livestock production. These technologies have changed the total production of agricultural commodities in the country.

Introduction

Adversities of climatic factors in arid and semi-arid regions accelerate soil moisture deficit and chance of crop failure throughout the world (Lawless et al., 2008). Increasing human population is placing unprecedented demand for food and natural resources. It has been estimated that an increasing population and changing dietary intake will lead to about 80–120% increase in global food requirement by 2050 (FAO 2006; Foley et al., 2012). This large amount of food production cannot be achieved by the agricultural sector alone, rather through a combination of technological innovations and involvement of other natural ecosystems (Licker et al., 2010).Traditional tree-integrated farming systems are adopted since time immemorial for security of food, fodder and fuel wood in drought-prone arid region (Harsh et al.,1992; FAO 2013), but are unable to meet the requirement of the ever increasing population.

Introduction

Remarkable increase in fruit and vegetable crops cultivation under arid region of western India lead to drastic changes in the pest population dynamics. The productivity is concern, it is low because of harsh environment (high temperature, low precipitation, high PET, high wind velocity), poor soil fertility and salinity. Beside these, the biotic pressure like pests and diseases also play a critical role, which cause significant loss and adds to the cost of production.

Introduction

Food is the most basic necessity for man. Plants are primary producers of food. Plants are the very pivot of our existence on earth and without plants the earth would be without life. The success or failure of crop production relies on interaction among varieties/genotypes, inputs used, environment and management factors. Plant diseases caused by fungi, bacteria, viruses, phytoplasmas and nematodes reduce crop yields (Khoury and Makkouk, 2010). Arid fruit crops like ber, aonla, date palm, pomegranate and vegetables like watermelon/mateera, kachri, snapmelon, muskmelon, ridge gourd and sponge gourd are mostly grown in Central and Western India. Horticultural crops can be infected by wilt, leaf spots (due to excessive moisture), mosaic and post harvest fruit rots. These diseases are major challenges in the cultivation of horticultural crops in India. Disease incidence in a crop is governed with the seed materials used and environment surrounding seed/plant.

Introduction

Abiotic stresses adversely affect growth, productivity and trigger a series of morphological, physiological, biochemical and molecular changes in plants. Cold stress is a major environmental factor that limits the agricultural productivity of plants in hilly areas. Plants respond and adapt to this stress to survive under stress conditions at the molecular and cellular levels as well as at the physiological and biochemical levels. However, expression of a variety of genes is induced by different stresses in diverse plants.

Introduction

Cultivation under house are framed or inflated structures covered with plastic material or glass in which crops can be grown under partially controlled environment.  This technology was well adapted in Europe and USA by the end of the nineteenth century. Presently, China, Netherland, Israel, Canada, Spain and Japan are the leading countries. Other countries where this technology is being widely used are India, Egypt and some Arab countries. Under protected structures are suitable for growing a variety of vegetables, fruits and flowers. Year-round cultivation even under extreme climatic conditions is possible.

Vegetable production in our country is significantly influenced by the seasonality and weather conditions. Extends of abundance and deficiency in production and availability cause considerable fluctuations in the prices and quality of vegetables. Vegetable production, at present, is also characterized by a strong dependence on chemical plant protection with its all inherent environment and health hazards, both for growers and the consumers. Strinking a balance between all-season availability of high quality vegetables with minimum environment impact, and still to remain economically competitive in this time of globalization, is a major challenge for the modern technology of crop production. The crop productivity is influenced by the genetic characteristics of the cultivar and the management practices including nutrients, water and microclimate. Under open field cultivation, while the other factors could be taken care of, it is not possible to effect control on the microclimate around the plant.

Date palm (Phoenix dactylifera L. Family-Palmaceae) also known as Khajoor or Kharek is an ancient important fruit tree of semi-arid and arid regions of the world. It grows well under poor desertic soils due to its hardy plant characteristics and deep root system. It is also one of the most suitable fruit trees, which can be easily grown under saline conditions. Date palm grows as much as one feet per year, and as high as 80-100 feet under favorable environment. It is well known fact for date palm that its feet in the water and its head in sun. It requires dry hot climate for growth and development of fruits. In arid region, crop production is risky preposition, where date palm cultivation contributes in achieving food security, high nutritive value food, crop diversification, desertification control, income generation and foreign exchange earnings. It can be grown at such places, where adequate irrigation facility is available; besides, other climatic requirements (Chandra et al, 1992, Singh et al, 2007). The date tree has religious significance. The fruits are used during holy month of Ramzan by Muslim peoples. As Saudi Arabia is principal producer of date palm in the world, the palm tree is incorporated in the national emblem of Saudi Arabia to represent vitality and growth

Introduction

Plants are often subjected to unfavorable environmental conditions – abiotic factors, causing abiotic stresses - that play a major role in determining productivity of crop yields but also the differential distribution of the plants species across different types of environment. Some examples of abiotic stresses that a plant may face include decreased water availability, extreme temperatures (heating or freezing), decreased availability of soil nutrients and/or excess of toxic ions, excess of light and increased hardiness of drying soil that hamper roots growth. The ability of plants to adapt and/or acclimate to different environments is directly or indirectly related with the plasticity and resilience of photosynthesis, in combination with other processes, determining plant growth and development, namely reproduction. A remarkable feature of plant adaptation to abiotic stresses is the activation of multiple responses involving complex gene interactions and crosstalk with many molecular pathways.

Introduction

According to FAO estimates, about 50% total geographical area in India is under various degraded hazards and about 2.1 million ha of land is getting degraded and deforested annually (Sehgal et al., 1998). Out of that underground water in arid and semi-arid areas is saline or sodic in nature. While spices, medicinal and aromatic plants may be a boon for these areas, which not only withstand under adverse conditions but also could be productive and helps in mitigating these problems. However, other crops are remain less or unproductive in these areas.

Introduction

Under arid and semi-arid regions of the world, major problems are salinity, alkalinity and calcareousness, which seems to further aggravate with changing climate scenario. Besides, most of the developing countries lies in this zone with flanging population resulting from shrinking of land resource and good quality of irrigation water. Globally area under saline/sodic soils is about 953mha covering 8% of the land surface. Resent estimates indicate that 6.7 mha area in India is affected by soil salinity and alkalinity and about 25% of ground water are sodic and/or saline in the country. There are two important approaches for utilizing saline alkali or calcareous environment. The first one is to modify the environment so as to suit the plant or modifying the plant and the second one is to substitute the plant species so as to suit the environment. However, second option is cost effective and most sustainable.

Introduction

The hot arid region of the country is spread over nearly 31.7 million hectare land area in different states. The major part of hot arid region of the country lies in western Rajasthan (19.62mha) followed by North-western Gujarat (2.16mha). The major natural constraints in arid vegetable production comprise of very low and variable rainfall (100-450mm), very high potential evapo-transpiration rate, intense solar radiation (320-619/cm²/day), high wind velocity (20km/hr), high infiltration (9cm/hr), extremes of temperature (0 to 48^ºC), low relative humidity, high soil salinity, very deep ground water, etc. These bio-physical constraints reduce the productivity of cucurbits many fold. Despite  several constraints, the hot arid areas of western Rajasthan offers very good opportunity for cultivation of cucurbits like, watermelon, muskmelon, longmelon, bottle gourd, ridge gourd, tinda, summer squash, cucumber, etc.

Introduction

The hot arid zones of the country are spread over 32 million ha in the state of Rajasthan (61%), Gujarat (20%), Andhra Pradesh (7%), Punjab (5%), Haryana (4%), Karnataka (3%) and Maharashtra (0.4%), in addition to the cold deserts in the states of Jammu and Kashmir and Himachal Pradesh which are characterized by hostile agro-climate and fragile eco-system. In Rajasthan, the hot arid zone covers 12 district of whole western Rajasthan. It covers the 61 % area of the Rajasthan State and characterized by an annual rainfall between 100 – 500 mm with a coefficient of variation (CV) varying from 40 – 70 per cent; low and erratic rainfall combined with extremes of temperature (450-500 cal/cm2/day); low relative humidity; high potential evapo-transpiration value ranging from 1600 mm in eastern part and 1800 mm in western part of the region.

Continuous vegetable cultivation year round in the limited available land, without adopting crop rotation practices induces stress, which leads to low vegetable crop productivity. These conditions apart from building up soil-borne pathogens will also lead to other deleterious factors such as temperature extremes, flooding, drought, salinity, heavy metal contamination, insufficient nutrient uptake, soil pH stress, etc. causing severe crop loss. To overcome these abiotic stress conditions, grafting is an environmentally friendly technique for reducing losses in production in solanaceous and cucurbitaceous vegetable crops. The cultivated area of grafted Solanaceae and Cucurbitaceae has increased tremendously in recent years because the objective of grafting has been greatly expanded (Lee et al., 2010) to reduce infections by soil-borne pathogens and to enhance the tolerance against abiotic stresses.

Introduction

In-spite of environmental, bio-physical and resource constraints in most parts of Rajasthan, the state can be classified into three distinct agro-climatic zones namely hot arid, semi-arid and sub-humid  from horticultural perspective. These diverse zones have excellent vegetable production potential with wide range of crops, varied opportunities and resource utilization. The extremes of high (March–October) and low (December–January) temperature conditions together with associated abiotic stresses in the hot arid and semi-arid regions limit the choice of crops and their genotypes, quality of produce and productivity. Vegetable exploitation with adaptive and native crop-plant species is generally found to be potential and stable under arid to semi-arid agro-climatic conditions of the state that receive 150–650 mm of rainfall and having abiotic stresses due to climatic variations, drought, frost, hot and cold winds, soil and water quality.

Rajasthan is the largest state covering about 34.2 million hectare geographical area of the country, of which 27.1 million ha (79 %) is under arid and semi-arid sub-tropic hot climate and spread over 21 districts. The land-scape of Aravali range provides boundary for arid western, semi-arid eastern and sub-humid to humid areas of the state. In-spite of several environmental restrictions and bio-physical constraints in most of the parts, the state can be classified into three distinct agro-climatic region i.e. hot arid, semi-arid and sum-humid from horticultural perspective. On the basis of research experiences and SWOT analysis over last two decades for R&D road-map of Rajasthan Horticulture, the classified zones have excellent vegetable development potential with wide and varied opportunities of crops and utilization of resources.

Introduction

Date palm (Phoenix dactylifera L., Family: Palmaceae) also known as Khajoor, Kharek is an ancient important fruit tree of semi-arid and arid regions of the world. It grows well under poor desertic soils due to its hardy plant characteristics and deep root system. It is also one of the most suitable fruit trees to grow under saline irrigation conditions. It is well known fact that date palm has its feet in the water and its head in sun. It requires dry hot climate for growth, development and maturity of fruits. In arid region, crop production is a risky preposition where date palm cultivation contributes in achieving food security, high nutritive value food, crop diversification, desertification control, income generation and foreign exchange earnings. It can be grown at such places where adequate irrigation facility is available besides dry hot climatic conditions (Chandra et al., 1992; Singh and Dhandar, 2007).

Introduction

High population pressure has forced us to plough 46% of our country area for food production. The present productivity of 12.36 tones/ha of fruits needs to be raised to 40.0 tones/ha by using N, P₂O₅, K₂O with other inputs, since recommended ratio is 0.75:0.50:1.00. To achieve this target, the present day requirement of 0.67 million tones N, 0.46 million tones P₂O₅ and 0.91 million tones K₂O has been raised to 1.07, 0.58 and 1.14 million tones, respectively in order to supply the recommended ratio of fertilizers to an area of 3.65 million ha growing fruits (Yadav, 1999). Similarly in vegetables, the present production level of 13.41 tones/ha to be raised to 40 tones/ha requires 1.25 million tones of N, P₂O₅ and K₂O combined at the ratio of 1.33: 0.88 and 1.00.

Introduction

Canopy management is the manipulation of tree canopies to optimize the production of quality fruits. The canopy management, particularly its components like tree training and pruning, affects the quantity of sunlight intercepted by trees, as tree shape determines the presentation of leaf area to incoming radiation. An ideal training strategy centers around the arrangement of plant parts, especially, to develop a better plant architecture that optimizes the utilization of sunlight and promotes productivity. Light is critical to growth and development of trees and their fruits.