eChapters

The Gujarat state is located on the north-west of India between 20^o6' N and 24^o42' N latitude and 60^o24' E to 74^o24' longitude. The climate of Gujarat is semi-arid tropical . the summers are very hot, the winter season is uncertain and irregular. The Arabian sea and Gulf of cambay have a moderating effect on the climate of the coastal areas of the state.

The state has a coastline of 1600 km (27% of the country) out of which Saurashtra and Kutch has about 1125 km long coastal line. The total coastal cropped area of the state is 8.75 lakh ha (9.11% of total cultivated area) spread over three agro-climatic regions of the state, out of which 91% comes under arid and semiarid climate type (Table 1). The important crops of the region are groundnut, bajara, sorghum, cotton, and wheat. The ground water availability is also scare. In the state recently the soil degradation through salinity has caught hold over 1.2 m ha of land, of which, about 0.3 m ha occurs in the coastal area. About 1125 km long coastal line is in Saurashtra and Kutch which comprises about 0.1079 m ha of saline land which needs to be treated for salinity reduction.
 

Importance

Drought is a climatic anomaly characterized by deficient supply of moisture, which may result from sub-normal, untimely and unevenly distributed rainfall. Among the various hazards of nature, drought is one of the major disasters because it brings innumerable miseries to the mankind. Almost every year some part or the other of the country suffers from such calamities. Drought is a recurring phenomena and its occurrence cannot be avoided. However, its impact can be minimized through application of science and technology by developing drought management plans.

For better yield irrigation water must be free from soluble salts and from concentration of specific chemical substances that may hazard to soil with respect to salinity, sodicity, alkalinity and toxicity. Water analytical data which helpful to predict the magnitude of the effect of irrigation water on soil and plant growth under specific environmental circumstances so irrigation water must be analyzed for EC, pH, Na+, Ca⁺⁺, Mg⁺⁺, Cl^-, CO₃–, HCO₃-  and SO₄.^– 

Agricultural land drainage is adopted for removal of excess surface and subsurface water, either from irrigation or rainfall in order to improve the profitability of land use.  Drainage also plays a role in removal of salts from the root zone. Therefore, land drainage is closely linked to irrigation in arid and semi arid regions. India has a long history of practicing irrigation and drainage in its semi arid irrigated regions. During the ancient times in the Indus Valley dams and drainage system were built for cultivation of different crops. The earlier experience of drainage was more concerned with surface drainage because from time immemorial India has been experiencing floods of varying magnitudes.

India is an agricultural country. The geographical area of India is about 328 mha out of which 147 mha of land under cultivation and 84-mha land is under irrigation. The population is increasing at an alarming rate that requires producing more food for the growing population. This problem can be solved either by increasing the land under irrigation or using different soil water conservation techniques. It is well known fact that during rainfall a considerable amount of water goes to sea due to high rate of runoff. It is highly needed to trap as much as water falling in the form of rainfall and recharge the groundwater so that it is made available for irrigation purposes.

Mulching

The technique of covering the soil with plastic films or natural crop left over (residues) for soil and water conservations is called mulching.

This technique was practiced by farmers using dry leaves straw, trash, stones etc to conserve water. Presently plastic film have come into use for the purpose of mulching due to inherent advantages.

Introduction

Salinity in India is a major issue affecting the sustainability of irrigated as well as non-irrigated areas particularly in the states of Rajasthan, Gujarat, Haryana, Uttar Pradesh, West Bengal and Orissa. Salt affected soils are unproductive unless excess salts are reduced or removed. These soils occur most extensively in arid and semi-arid climates, but these soils are also found in coastal sea areas where soils are unundated by ocean or sea water. Soils are said to be saline if they contain an excess of soluble salts and sodic or alkali if they contain an excess of sodium salts. Again soils are said to be saline-sodic or saline-alkali if they contain appreciable amounts of both soluble salts and sodium. The impact of salinity manifests itself in several ways. As the salinity increases, not only does the productivity decline but sensitive crops also go out of cultivation and are replaced by salt-tolerant, low value crops and other plant species.

Soil Erosion As a Process
 
Soil erosion is a three stage process, namely (1) detachment, (2) transport, and (3) deposition of soil. Different energy source agents determine different types of erosion. There are four principal sources of energy: physical, such as wind and water, gravity, chemical reactions and anthropogenic, such as tillage. Soil erosion begins with detachment, which is caused by break down of aggregates by raindrop impact, sheering or drag force of water and wind. Detached particles are transported by flowing water (over-land flow and inter-flow) and wind, and deposited when the velocity of water or wind decreases by the effect of slope or ground cover. Processes like dispersion, compaction and crusting, accelerate the natural rate of soil erosion. These processes decrease structural stability, reduce soil strength, exacerbate erodibility and accentuate susceptibility to transport by overland flow, interflow, wind or gravity. These processes are accentuated by soil disturbance (by tillage, vehicular traffic), lack of ground cover (bare fallow, residue removal or burning) and harsh climate (high rainfall intensity and wind velocity).

Aquaculture is the cultivation of fish, molluscs, crustaceans (shell fish) and aquatic plants in controlled conditions, provides an increasingly significant proportion of food production globally. The sector has represented the greatest growth of all food production systems in the last two decades and an estimated 10% yearly increase in output is likely to bring productivity to a predicted 47 million tonnes in the year 2010 (Pedini and Shehadeh, 1997). Significantly, the greatest contribution to total production and the greatest rate of uptake of aquaculture activity is in the developing world. More than 82% of the total global yield in 1999 was produced by developing countries (GESAMP, 2000) and growth rates between 1984 and 1995 were six times higher than that from developed countries (Rana, 1997; Tacon, 1996).

Groundwater is a precious renewable resource which gets replenishment from the precipitation. Total water resources of the world are estimated at 1.37 x 10⁸ million ha-m. Of these, about 97.2% is salt water, mainly in oceans, and only 2.8% is available as fresh water. And, out of this 2.8%, about 2.2% is available as surface water (2.1% is fresh water in glaciers and icecaps, 0.1% is available in lakes and reservoirs, 0.0001% in streams) and 0.6% is available as groundwater. Only 50% of groundwater resource is economically extracted with available technology. Presently, 1.3 x 10⁴ million ha-m fresh water in reservoirs and 41.1x10⁴ million ha-m groundwater is theoretically available to provide usable water for drinking, domestic use, irrigation, etc., to mankind. Groundwater is the largest source of fresh water excluding the polar icecaps and glaciers. The amount of groundwater within 800 m from the ground surface is over 30 times the amount in all fresh water lakes and reservoirs, and about 3000 times the amount in stream channels, at any one time.

Experiment

An experiment is a planned inquiry to obtain new facts or confirm or deny the result of previous experiment. Such inquiry can aid in an administrative decision, such as recommending a variety, a feed, a cultural practices, a fertilizer, a pesticide or a fungicide etc.

Type of Experiments

    1.     Preliminary experiments : Here investigator tries out large number of treatments in order to obtain leads for future work. Here replications are not taken for such treatments tried e.g. number of pesticides for control of diseases - take single observation for each treatment and take decision that some of them worth trying for use.

The coastal agro ecosystem is very important among the different agro ecosystems of our country both economically and environmentally. It spans over a length of 8129 sq. km. covering 9 states and 2 Island ecosystems. Agriculture and allied activities constitute the single largest component of India’s economy, contributing nearly 27 per cent of the total Gross Domestic Product (GDP) in the year 1999-2000 (TERI, 2002). Agriculture exports accounts for 13 to 18 per cent of total annual exports of the country (MoF, 2002). However, given that 62 per cent of the cropped area is still dependent on rainfall (MoEF, 2002). Coastal agricultural region comprises of hinterland, which has a varied geometric and topographical features of mountains valley, coastal plains, riverine systems, climatic conditions, different soils and water bodies, vegetation ranging from rich tropical rain forests to coastal mangroves and a wide range of crops that are cultivated in this region (Table 1). The agro climatic conditions of the coastal zones are congenial for growing various field and horticultural crops.

Introduction

Indian agriculture was contributing 70% to total GDP of the country at pre-independent time, but it decreased drastically year by year and contributed 66.8% in 1960, 55.6% in 1994, 27.1% in 1997 and now a days, it reached only to 25% in 2001. With the advancement of civilization our population is increased, whereas, the cultivable lands is decreased side by side, thus, on an average income of agriculture is decreased.

Gujarat is the leading state to concern with the productivity, production and the area of the some crops like Groundnut, Castor, Cotton, etc. in India. The major part of the state is surrounded by sea coast border, which is 1600 km. Gujarat is popular for production of oilseed crops like groundnut, cotton ; horticultural crops like mango, chiku, coconut, banana, papaya, citrus; spices crops like chili, cumin, funnel etc.

Introduction

The globally growing demand for water has ushered the need for its efficient and judicial utilizations in all fields, and agriculture in particular being a single largest consumer of water. The majority of irrigation projects in India perform at a very low efficiency, which calls for application of efficient water management technologies for meeting the increasing water demands. Estimation of soil moisture or crop evapotranspiration from climatic parameters provides objective criteria for irrigation management. Methods to estimate evapotranspiration require huge climatic data, which are seldom available and not applied by common crop growers. Determining crop water requirement through soil moisture measurement at several locations is time consuming, destructive exercise, and may not give proper assessment of crop water need. The plant based indicator approach considers the plant water status for scheduling irrigation. This might be considered as the ideal criterion because the plant water is a good integrator of the soil, water and climatic parameters.

Introduction

Water is a precious natural resource vital, for sustaining all life on the earth. It is in a continuous circulatory movement - hydrologic cycle. It is not uniformly distributed in time and space. Due to its multiple benefits and the problems created by its excesses, shortages and quality deterioration, water as a resource requires special attention. On a global scale, total quantity of water available is about 1600 million cubic km. The hydrological cycle moves enormous quantities of water about the globe. However, much of the world’s water has little potential for human use because 97.5% of all water on earth is saline water. Out of remaining 2.5% fresh water, most of which lies deep and frozen in Antarctica and Greenland, only about 0.26% flows in rivers, lakes and in the soils and shallow aquifers which can be readily used. Sustainable water management in India is fast becoming a necessity, with the looming crisis over water resources in the country threatening the security and livelihood of the population and the environment over the coming decades. Managing water resources, river catchments, and coastal zones are outstanding challenges of today and tomorrow’s. Global changes ask for a comprehensive scientific approach, an international multi-disciplinary orientation and require a new mind-set towards water and coastal management problems.

Perennial vegetables live/survive in field for several years and go on yielding vegetables without much care and attention.  They are usually planted on the side of kitchen garden without much interference with tillage operations of other annual crops.  Tender leaves, shoots, fruits or tubers of a number of perennial crops are used for vegetable purpose in different agro-climatic conditions. They may be trees or shrubs as in bread fruit, jack fruit, drumstick, etc. or bushes as in colocasia or trailing plants as in yams, chow-chow and ivy gourd.

Vegetables which are consumed raw without cooking are known as salad crops.  In temperate regions, a large number of quick growing cool season crops like lettuce, celery, parsley, endive, chicory, chervil, cress, water cress etc. are consumed as raw. Only lettuce and celery are cultivated on a commercial scale in developed countries.  Growing awareness on nutritional values of raw vegetables and also health consciousness of people resulted in increased consumption of salad vegetables in tropics too.  Vegetables like onion, cucumber, tomato, carrot, radish, beet root, cabbage, capsicum, melon etc. are used as salads without cooking.

Leaf vegetables are rich sources of provitamin-A, vitamin-C and minerals like calcium, iron etc.  They also provide roughage required in human diet.  The Indian Council of Medical Research (1984) recommended a daily intake of 100 g and 40 g of leaf vegetables in the diet of woman and man, respectively. Amaranth, beet leaf, spinach, fenugreek, cabbage etc. are the major leaf vegetables grown in the country. In addition, a number of under-utilized annual crops are also grown as leaf vegetables in specific regions. Tender stems and leaves of a number of perennial crops are rich sources of vitamins and minerals and are used for cooking.  The major annual leaf vegetables have a few features in common:

Tropical tuber crops are an important group of subsistence crops in tropical and subtropical zones.  Carbohydrates synthesised and stored in the form of starch in underground tubers are used as food by millions in under-developed countries.  It is also used as raw material by many industries.  Cassava, sweet potato, Chinese potato, edible aroids like elephant foot yam, taro, tannia and yams like greater yam, lesser yam and white yam are major tuber crops  grown in India.

Tuber crops are mainly grown as rainfed with minimum cost of production.  All are propagated through vegetative means and require fertile and well drained loose soil for proper root development. All roots crops require high dose of potassium for high productivity.

Potato is fourth major food crop after rice, wheat and maize in the world.  It produces the highest dry matter, well balanced protein and more calories/unit area and time.  Unlike other food crops, potato tubers contain vitamin-c (17 mg/100 g). It provides carbohydrates, minerals, fibre and a number of vitamin-B groups.  Potato protein is comparable to that of milk and egg.  Unlike European countries, in tropics and sub-tropics, the crop is of short duration and fits well in intensive cropping system.  It can be grown in a wide range of climatic and soil conditions and tubers are available throughout the year. Tubers can be left un-harvested in the soil for some time and are also suitable for long distance transport and storage. Several products like chips, flakes, French-fries, finger chips, granule, disc, cubes and flour are made out of potato tubers.