eChapters

14.1. Slope
It is a crucial topographic factor that affects water drainage, erosion and accessibility of agricultural machinery. Steep slopes increase the risk of soil erosion, and water run-off requiring erosion control measures such as contour ploughing or terracing. Slope also affects the availability of sunlight, as steeper slopes may cast shadows and influence microclimates within a field.
14.2. Altitude / Elevation
Elevation is the vertical distance of a point or location above a reference point, often mean sea level. It influences temperature, atmospheric pressure, and the types of crops that can be grown in an area. Higher altitudes generally experience cooler temperatures, which may limit the choice of crops that can thrive. Elevation affects the length of the growing season and influences the choice of appropriate crop varieties. In summary, elevation is an absolute measure of the vertical distance above a reference point (such as MSL), while it is a relative measure that describes the variation in elevation within a specific area or region. Elevation provides information about the height of a point, whereas it provides insights into the topographic features and slopes of a given agricultural landscape. Both elevation and relief are important considerations in agriculture as they influence factors such as water drainage, temperature gradients, and suitability for specific crops.
14.3. Aspect
Aspect refers to orientation of the slope (north, south, east or west). It affects the distribution of sun light; wind patterns and temperature gradients in a field. In the northern hemisphere, the north side of slope is often shaded while the southern side receives more solar radiation and heat, creating warmer microclimates and potentially influencing the choice of crops or planting strategies. Aspect can also impact the risk of frost or cold air drainage in certain regions. Whereas, in the southern hemisphere, the south side slopes get shaded and north facing slopes receive more solar radiation.
14.4. Relief
Relief refers to the variation in altitude between different points. It is a relative measure on changes in altitude across a particular landscape or agricultural area. The valley slopes are preferred sites for agriculture in mountain regions due to several reasons:
• The valley slopes offer relatively flatter terrain, making it easier for farming activities such as cultivation, irrigation and mechanization.
• The valleys tend to have better access to water resources such as rivers or streams which can be used for irrigation water.
• The valley slopes provide good sun exposure and protection from strong winds creating favourable microclimates for crop growth
• The natural drainage patterns of valleys help preventing water logging and ensure better water management.

Abstract

The present experiment was conducted to study the influence of weather parameters on the population dynamics of insect pests of rice during 2009-10 at ICAR-RC for NEH Region, Mizoram Centre, Kolasib, Mizoram. The result of the study indicated that, the mean populations of peak abundance of major insect pests rice crops during August were stem borer, flea beetle and gundhi bug. The Correlation studies showed that stem borer population a significant positively correlation was observed with maximum and minimum relative humidity. Nevertheless non significant negative correlation was obtained with maximum and minimum temperature. The finding of the present study indicated a positive non significant correlation with maximum relative humidity, maximum and minimum temperature where as negative insignificant correlation with rainfall and minimum relative humidity with flea beetle population. The highest minimum temperature showed a positive significant correlation with the Monolepta.

The ozone layer is a region in the Earth’s stratosphere where a certain amount of incoming solar radiation is absorbed. Over the last twenty years or so a series of man-made threats to it have been reported and each has been treated  with more gravity than the last. Now a-days such threats feature  regularly on the agendas of international conferences.

Ozone, Positive and Negative : Ozone, or trimolecular oxygen (O3) can be advantageous or exert harmful influence on human health, as well as that of other organisms. It is all depends on whether it is present in the troposphere or stratosphere (Fig. 8.1). In the stratosphere, ozone is a beneficial serving as a shield in screening out most of the damaging portions of ultraviolet radiation which have wavelengths between 290 and 320 nanometers. In the troposphere, ozone is a negative as it appears as a component of smog with a number of deleterious effects, as will be discussed below.

Abstract

As such in search of alternative to chemical insecticides against insect pest of rice resulted in identifying white muscardine fungus, Beauveria bassiana an entomopathogen out of several entomogenous fungi prevalent in rice ecosystem as the potential mycoinsecticides. The fungus has 78-87% virulence against rice hispa with  LC 50 value of 90.16. Under field situations it is required that the effectiveness of the bioagents are enhanced by combining them with compatible pesticides. A sublethal dose of a pesticide  would make the insect physiologically weak which makes it much more susceptible to the attack of the entomogenous organisms. In view of this, compatibility test was conducted with 14 different commonly applied insecticides at two different doses i.e., recommended and half of the recommended dose. In small scale field trial chloropyriphos at half of the recommended dose along with B. bassiana was the best treatment in controlling the pest along with increased yield of the crop consecutively for two years.

ABSTRACT

An in vitro evaluation was carried out to find out the efficiency of bacterial and fungal antagonists in checking the growth of pathogens of Kacholam. Out of the two methods tried to find out the effectiveness of Pseudomonas fluorescens against the two isolates of Ralstonia solanacearum, cross streaking produced lysis at the juncture and point inoculation produced clear inhibition zones. Among the two fungal antagonists tested Trichoderma viride was more efficient than Aspergillus niger because of its faster growth over the pathogen. However, both the antagonists showed complete overgrowth and dense sporulation on the area where the pathogen was streaked. To find out the efficacy of Pseudomonas fluorescens against leaf spot pathogens like Colletotrichum gloeosporioides and C. capsici, streaking on both sides yielded more than 50 per cent reduction in growth of both the fungal pathogens. The fungal antagonist T. viride showed a faster growth over pathogens than A. niger eventhough both recorded an antagonism index of 1500. Dense sporulation was seen over the pathogens in case of T. viride. The ability of fungal antagonists to produce volatiles and their effect on fungal pathogens were also assessed. It was noticed that the volatiles produced by T. viride was more effective than that of A. niger. Even though the extent of inhibition was less compared to direct action, this could also be one of the mechanisms of action of both the antagonists. The study revealed that all the three antagonists were effective against both bacterial and fungal pathogens and they could be utilized under field conditions.

Abstract

Lentil is an important pulse crop and play very important role in the supply of the protein to under nourished vegetarian population of the country. Fusarium wilt of lentil caused by Fusarium oxysporum f. sp. lentis is one of the wide spread and destructive diseases in India under rice-based cropping system. Use of synthetic fungicides has led to the emergence of several problems like environment pollution, residual effect in grains and killing of non-target organism(s). Hence, for minimizing the losses caused by Fusarium wilt, four plant extracts such as Garlic, Neem, Eucalyptus, Tulsi and three antagonistic bio-agents viz. Trichoderma viride, Trichoderma harzianum and Pseudomonas fluorescence were evaluated in vitro. The results clearly showed that all plant extracts were more or less inhibitory to mycelial growth of Fusarium oxysporum f. sp. lentis. The effectiveness of extracts increased with increase of their concentration and maximum growth inhibition was obtained in Eucalyptus followed by Garlic and Tulsi. While minimum per cent inhibition was recorded in Neem. Among bio-agents, T. viride showed maximum growth inhibition of Fusarium oxysporum f. sp. lentis followed by T. harzianum at both 4 and 7 days incubation period.

Abstract

Microbial inoculants are low cost inputs with high benefits in agriculture. Solid carrier based (peat or lignite) inoculants are used in most tropical countries. The carrier based inoculants have short shelf life, are liable to have high contaminants and have shown inconsistent field performance. In recent years, special liquid formulations containing not only the desired microorganisms and their nutrients but also added cell protectants or chemicals that promote formation of resting spores or cysts have been developed. The liquid formulations have longer shelf-life (12 months at room temperature) and are also more tolerant to adverse conditions encountered in storage. Liquid Rhizobium biofertilizers enhanced the soybean crop yields in the United States of America, Brazil, Europe and Asia over carrier based inoculants.

ABSTRACT

The main function of extension is to bring a desirable change in human behavior. The extension workers, thus are essentially educators and their most important job is to communicate useful and practical research findings to the farmers in such a way that they understand, accept and adopt. In order to achieve this objective, the extension agencies are disseminating new technologies through different means including mass media like radio, T. V, and print media. Considering the wide areas of coverage, exposure and frequent use by people, the mass media such as television, newspaper and radio play an important role in the transfer of technology. Mass media are increasingly becoming a veritable instrument and tool for transforming agriculture. Hence, mass media play a vital role in agricultural extension. There is a gap between the agricultural researchers and the farmers. A lot of findings from the research institutions and laboratories are not used by the farmers, either because of the information did not reach them, or the received information was not implemented by them. To overcome this problem, mass media play a vital role in diffusing scientific knowledge among the mass. This is used to link researchers and extension workers and collecting the feedback from farming communities. Further, agricultural technology information acquired by farmers through mass media. Generally, the agricultural technology information includes techniques of applying fertilizer, insecticides and fungicides to crops, improved methods of cultivation and conservation techniques of planting, maintenance, harvesting and storage of crops. There are also new technologies of animal husbandry as well as processing and marketing various agricultural products. Hence, mass media is the most effective means of reaching people with new ideas and persuading them to utilize these innovations. The appropriate use can create knowledge and catalyze behavioral change among farming communities for better family farming.

Abstract

The major losses of banana at present by Panama wilt disease pathogen of banana and its management is very typical because it is caused by a soil-borne pathogen (Fusarium oxysporum f.sp. c u b e n s e ). The micronutrients are used to manage the disease as well as it provides the healthiness of plant and increases the fertility of the soil that’s why the plant is free from the disease or less infected. An experiment of micronutrients was conducted in the laboratory of plant pathology BAU, Sabour for Invitro evaluation of the micronutrients viz. Zinc Sulfate, Ferrous Sulfate, Ammonium Sulfate, Copper Sulfate, Calcium Nitrate, Borax and Potassium Chloride against Fusarium oxysporum f.sp. cubense causing Panama wilt of banana. The results of the experiment revealed that among the micronutrients used, Borax @ 500 and 750 ppm completely inhibited the mycelial growth of FOC followed by Zinc Sulfate (45.7, 42.6, 39.2 and 18.5 mm at 100, 250, 500 and 750 ppm respectively). The incorporation of borax in the solid medium at higher concentrations viz., 500 and 750 ppm is very effective for the management of Panama wilt disease of banana. This approach leads to maintain our ecosystem sustainability for a longer time and manage the disease.

Abstract

European red mite is a  serious pest of apple in Himachal Pradesh. Recent survey has shown that 80 per cent apple orchards are infested with this pest. As a result of continuous feeding fruit remained undersized, poor coloured and sour in taste. New acaricides fenazaquin (0.001%) and propergite (0.057%) proved highly effective Standard acaricides dicofol ( 0.037%) and insecticide endosulfan (0.07%) remained effective upto 15 days only.

Abstract

Pigeon pea is an important pulse crop of India and its production is greatly affected by wilt disease. Pigeon pea wilt is a very destructive soil borne disease caused by Fusarium udum. In present research work plant extracts (Garlic, Neem, Tulsi), bio-agents (Trichoderma viride and Pseudomonas fluorescens) and fungicides (Vitavax, Bavistin and Thiram + Carbendazim) were tested against Fusarium udum. Among them fungicides were found most effective in inhibiting mycelial growth of Fusarium udum recorded 100% inhibition followed by garlic bulb extract (52.12 to 56.33%). Among bioagents, Pseudomonas fluorescens inhibit the growth up to (46.00 to 51.79%) followed by T. viride (44.32 to 48.79%) amongst all treatments except untreated.

Keywords: Pigeon pea, Fusarium udum, bio-agent, fungicide

Pigeon pea (Cajanus cajan L. Millsp.) is one of the major pulse crops grown in the tropics and subtropics belonging to family Leguminaceae. It has wide adaptability and low input requirements mostly grown in kharif season.

ABSTRACT

Phytophthora rot is the most destructive disease of black pepper nursery inflicting heavy crop losses. Considering the seriousness of the disease, the present study was undertaken to isolate and select the efficient antagonists from pepper nurseries raised in Government farms at Chelakkara, Pazhayannur, Mannuthy and Pananchery of Thrissur district. A quantitative estimation of the rhizosphere microflora from different nurseries revealed more abundance of soil bacteria followed by fungi and actinomycetes. Based on cultural characters of the rhizosphere microflora, 22 fungi, 20 bacteria and five actinomycetes were selected for further studies. Antagonistic action of soil microflora against Phytophthora capsici was studied by dual culture method in comparison with that of standard culture of T. harzianum. The study revealed that all fungal isolates and five bacterial isolates were antagonistic towards the pathogen with varying degrees. Among the fungal isolates, 13 isolates including T.harzianum recorded cent per cent inhibition of P.capsici. From among the fungal isolates that showed antagonistic reaction in dual culture, further selection of efficient ones was carried out based on the antagonistic index (AI). The isolate 22 F₂ (Trichoderma sp.) showed the maximum AI of 3000 followed by isolate 34 F₂ (Trichoderma sp.) and T. harzianum with an AI of 1500 each. The cultural and morphological characters of the efficient native isolates (22 F₂ and 34 F) were studied and were identified as Trichoderma longibrachiatum Rifai aggr. and Trichoderma viride Pers. ex S.F. Gray aggr. The three antagonists were found parasitic on P.capsici as evidenced by excessive coiling, penetration and disintegration of the hyphae and thereby these Trichoderma spp. used in the study is found to have effective parasitic effect on the pathogen in addition to some degree of antibiosis and these fungi could be utilised for the management of Phytophthora rot in black pepper nursery.

ABSTRACT

Phytophthora pod rot (PPR) incited by Phytophthora palmivora is the most serious disease of cocoa, inflicting heavy crop losses. Since, antagonistic microbes are useful in ecofriendly management of plant diseases, the present study was undertaken to harness the potential of antagonistic epiphytic microflora isolated from cocoa pods for the management of PPR of cocoa. A quantitative estimation of the epiphytic microflora from pods collected from different locations of cocoa gardens of Thrissur district revealed more abundance of bacteria followed by fungi, actinomycetes and fluorescent pseudomonads. The in vitro antagonistic effect of 16 isolates of fungi, 22 isolates of bacteria, five isolates of actinomycetes and two isolates of fluorescent pseudomonads from pod surface against P. palmivora was carried out in comparison with standard cultures of Trichoderma harzianum and Pseudomonas fluorescens. The study revealed that all the epiphytic fungal and bacterial isolates including standard cultures of T. harzianum and P. fluorescens were antagonistic to P. palmivora in varying degrees. Based on the in vitro screening seven promising epiphytic fungal isolates and five bacterial isolates along with standard cultures of T. harzianum and P. fluorescens were evaluated for their efficiency in reducing the infection by P. palmivora on detached pods. The pathogen was inoculated on the pods one hour after application of antagonists. Observations taken 10 days after inoculation of the pathogen revealed that one isolate of T. viride and two isolates of P. fluorescens obtained from pod surface exerted more than 40 per cent efficiency over control in reducing the infection. The standard cultures of fungal and bacterial antagonists recorded 33-35 per cent efficiency. Hence, these efficient epiphytic and standard cultures could be utilized for the management of PPR of cocoa.

Irrigation Efficiency
Irrigation water is an expansive input and has to be used very efficiently. The main losses that occur during irrigation of fields as conveyance, run off, seepage and deep percolation; Irrigation efficiency can be increased by reducing these losses. Uneven spreading and inadequate filling of root zone are the other causes for low irrigation efficiency. Irrigation efficiency at the field level can be increased by selecting suitable method of irrigation, adequate land preparation and engaging an efficient irrigator. At the project level, it can be increased by proper conveyance and distribution system. Irrigation efficiency is the ratio usually expressed as percent of the volume of irrigation water transpired by plants, plus that evaporate from the soil, plus that necessary to regulate the salt concentration in the soil solution and that used by plants in building plant tissue to total volume of water diverted, stored or pumped for irrigation.
Wt+Ws-RsEi=×100Wi
Where,
Ei = Irrigation efficiency (percent)
Wt = the volume of irrigation water / unit area of land transpired by plants, evaporation from the soil during the crop period.
Ws = the volume of irrigation water per unit area of land to regulate the salt Content of soil solution.

The objective of any cropping system is efficient utilisation of all resources such as land, water and solar radiation, maintaining stability in production and obtaining higher net returns. The efficiency is measured by the quantity of produce obtained per unit resource used in a given time.

Abstract

The groundwater targeting in hard rock aquifer systems is complex, because of the heterogeneity of the aquifer systems. The ground water mobility and stability in such aquifer systems varies because of the lithology, folded structures, fracture density, geomorphology, slope etc., These occur in various permutations and combinations and control the overall water holding and conducting capacity in different parts of the aquifer systems. Hence, one needs to analyse all the data so as to understand and bring out precise spatial models on the groundwater probability in hard rock aquifer systems. In the present study, the authors have carried out GIS based appraisals to understand the relation between the lithology and groundwater movement in hard rock aquifer systems of parts of Central Tamil Nadu covering 1300 sq.km. In the said study, GIS images were generated on the maxima zones of various aquifer parameters such as water level, width of aquifer depletion, transmissivity, permeability, specific capacity, storage co-efficient, optimum yield and recovery rate. These were overlaid with the lithology GIS image. Such an analysis has shown that, in general, the fissile hornblende biotite gneiss appears to have some control over the groundwater systems.

11.1 Performance of Farm Irrigation Systems

The performance of farm irrigation systems is determined by the efficiency with which water is delivered to the field and utilized to the fullest amount possible with minimum losses due to seepage and percolation, runoff, evaporation and other operational losses. The efficiency of the irrigation system will increase if the conveyance losses, application losses and other losses are reduced to a great extent.

11.1.1 Overall Efficiency

The overall efficiency of a farm irrigation system is defined as the percent of water applied to the farm that is used for irrigation on the farm. Irrigation efficiency otherwise called as overall system efficiency is defined.

About 60 per cent of total arable land (142 million ha) in India is rain-fed, characterized by low productivity, low income, low employment with high incidence of poverty and a bulk of fragile and marginal land. Watershed development program is, therefore, considered as an effective tool for addressing many of these problems and recognized as a potential engine for agricultural growth and development in fragile and marginal rain-fed areas. The Government of India has accorded high priority to the holistic and sustainable development of rain-fed areas through the integrated watershed development program since the 7th Five Year Plan (1985-90) and since then a number of watershed programs have been specifically launched in the rain-fed areas with the sole objective to improve the livelihood of poor rural households in a sustainable manner.

Water is indispensable for human, animal and plant life. It is a major component of all organisms some of which contain more than 90% of water. Water is a constituent of protoplasm. It maintains turgidity of cells which is essential for stomatal opening, expansion of cells and for different physiological processes. Water is also required for translocation of nutrients and dissipation of heat.

16.1 Irrigation

Irrigation is generally defined as the artificial application of water to soil for the purpose of supplying the moisture essential for plant growth.

However, a broader and more inclusive definition of the term irrigation is the application of water to the soil for any number of the following six purposes —

1. To add water to soil to supply the moisture essential for plant growth.
2. To provide crop insurance against short duration drought.
3. To cool the soil and atmosphere, thereby making more favourable environment for crop growth.
4. To wash out or dilute salts in the soil.

The conservation of soil and water is very essential for sustainable production, environment preservation and balanced ecosystem. Fifty percent of total geographical area (329 m ha) of our country needs soil and water conservation measures. About 5334 million tonnes of soil is lost annually along with 10 million tonnes of fertilizer and other essential nutrients and organic carbon. Loss of nutrients is almost equal to their total production in India. In India about 70% of the cultivated area falls under the category of dryland conservation measures for soil and water and efficient utilization of these resources is needed in these areas. The fact that rainfed agriculture supports 44% of India’s human population and contributes 90 percent of coarse cereals and pulses, 80 percent of oil seeds and 65 percent of cotton and growing realization that further gains in productivity of crops and live stock will emanate from rainfed regions, leave no room for complacency in this regard.

In these areas, rainfall frequently occurs with high intensity that produces higher runoff due to non adoption of soil and water conservation (SWC) measures and poor permeability of the soil. As a result crop grown during rainy season often suffer from moisture stress due to inadequate moisture storage in the soil profile. Secondly soil erosion problems such as sheet, rill and even gully erosion are common in the region.

It has been reported that the black soils of peninsular region of India, under cultivated fallow gives runoff of about 23.4 percent of rainfall and results in a soil loss of 8.94 t ha^-1 at 1.0 percent slope (Verma et al., 1990). They further reported that the rate of siltation reduced by 83 percent within a span of five years due to adoption of agronomic measure of SWC. These studies clearly showed that soil erosion and runoff are the major factors causing land degradation in the region that needs appropriate SWC measures so that crop productivity could be maintained.