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Organic farming in low rainfall areas – Kisan Suvidha
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Organic farming in low rainfall areas

organic farming method

Organic farming in low rainfall areas

Introduction

In the last few decades, awareness about health, social and environmental issues has increased. As a result, it is now well appreciated that organic farming is one of the agriculture production systems that not only is supportive to the clean environment but also is sensitive to the social issues like employment, health, migration, etc. Definitions given by two international organizations verify this concept. The definitions are:

 

  1. Organic agriculture is a holistic management system, which enhances agro-ecosystem health, utilizing both traditional and scientific knowledge. Organic agriculture systems rely on ecosystem management rather than external agricultural inputs (IFOAM, 2006).

 

  1. It is an environmentally and socially sensitive food supply system. The primary goal of organic agriculture is to optimize the health and productivity of independent communities of soil life, plants, animals and people (FAO, 2002).

 

In simple words “Organic farming is the production system that utilizes local resources in an optimum way so that sustainability of production and wellness of the society and environment are maintained for a fairly long time.”

 

Organic farming versus conventional (chemical) farming

Organic farming is commonly understood the exclusion of synthetic external inputs which is true but more important are the ideological differences between conventional farming that makes organic farming more suitable for society and the environment. Key differences are given below:

Organic farming Conventional farming
Holistic approach Reductionists approach
Decentralize production Centralize production
Harmony with NATURE(harness with nature) Domination in NATURE(exploit for profit)
Diversity Monoculture
Input optimization(save more) Output Maximization(spend more)

Conventional farming is also known as intensive chemical farming.

 

Objectives of organic farming

According to the International Federation of Organic Agriculture Movement (IFOAM), the objectives of organic farming are followed:

  1. To produce food of high nutritional quality in sufficient quantities
  2. To work in harmony with natural systems rather than seeking to dominate them
  3. To encourage and enhance the biological cycles within farming system involving microorganisms, soil flora, and fauna, plants, and animals
  4. To maintain and increase the long term fertility of soils
  5. To use, as far as possible, renewable resources in locally organized agricultural systems
  6. To work, as much as possible, within a closed system about organic matter and nutrient elements
  7. To give all livestock, conditions of life that allow them to perform all aspects of their innate behavior
  8. To avoid all forms of pollution that may result from agricultural techniques
  9. To maintain the generic diversity of the agricultural system and its surroundings, including the protection of plants and wildlife habitat
  10. To allow agricultural producers an adequate return and satisfaction from their work including a safe working environment
  11. To consider the wider social and ecological impact of the farming system

 

Essential characteristics of organic farming

The most important essential characteristics of organic farming are as follows:

  1. Maximal but sustainable use of local resources
  2. Use of purchased inputs, only as complementary to local resources
  3. Increasing crop and animal diversity in the form of polycultures, agroforestry, integrated crop/livestock systems, etc. to minimize risk and improve ecological balance and economic stability
  4. Ensuring the basic biological functions of soil-water-nutrient-humus continuum
  5. Creating an attractive overall landscape which gives satisfaction to the local people

Thus, to sum up, mixed farming, crop rotation, and organic cycle optimization are the three key principles of organic agriculture.

Advantages of organic farming

Some important advantages of organic farming experienced worldwide are:

  1. Organic farming creates optimal conditions in soil for improved growth and physiological activities of plants and the higher crop yield
  2. It improves soil physical, chemical, and biological conditions
  3. It improves soil carbon content (carbon sequestration)
  4. Organic farming utilizes organic wastes as inputs and thus minimizes pollution
  5. It mitigates environmental degradation
  6. It is more resistant to diseases, insects, and pests
  7. Organically grown produce are believed to be nutritionally superior and good for health.
  8. Higher demand for organically produced food coupled with its premium price may improve economy of the farmer and the region

 

Essential components of the organic farming

The three major components that create core environment for organic production system are:

  1. Maintaining agro-diversity through cropping system, integration of animals and other beneficial flora and fauna.
  2. Conservation and efficient utilization of local resources with least dependence on external inputs, and
  3. Fairness in production and utilization so that every stakeholder of the system gets his due share.

In the above major components, some location specific minor components can be included/excluded as per the resources available to the farmer.

Potential of Organic farming in low rainfall areas

Low rainfall areas (rainfall below 500 mm year-1) of the country cover about 45 million hectares major part is in Rajasthan (12 districts) and a small part in Gujarat, Andhra Pradesh and Tamil Nadu. In these areas, rains have erratic distribution, and frequent droughts also cause uncertainty in agriculture production. This condition is getting further aggravated due to climate change. It has been projected that impact of climate change by the end of the 21st century is more likely to be felt in low rainfall areas than in higher rainfall regions of India (Rao et al., 2009).

Traditionally, in low rainfall areas, multi-component farming systems are prevalent which include annuals, perennials, and animal components. These systems have minimal or no external inputs and are based on recycling of local resources and help in spreading the risk of rainfall uncertainty. Although these systems have sustained production reasonably under the prevailing climatic uncertainties, their productivities are very low which can be attributed to the inefficient use of local resources.

Under such conditions use of synthetic inputs i.e. fertilizers, pesticides, etc. is risk prone and uneconomic. In the last 4-5 decades several attempts have been made to improve the productivity of the traditional systems by use of synthetic external inputs e.g. fertilizers, pesticides, weedicides; however, the success was limited to the good rainfall years only. During below average rainfall years, negative results were also observed. Given the high cost of chemical fertilizers but uncertain yield gains by their use, Agrawal, and Venkateshwrlu (1989) suggested increasing the use of organic manure for sustainable production in low rainfall condition. This practice provides at least some produce even under prolonged dry spell. Balanced nutrition to plants through organic source may be a feasible option to mitigate the effect of climate-related uncertainty.

In low rainfall areas due to high risk associated with crop production, the use of agrochemicals is very less. Thus, farmers are practicing organic farming since ages by default. The system despite its low productivity compared to the conventional system has established itself as highly efficient regarding resource recycling and providing better food and economic sustainability in the arid region (Sharma and Tewari, 2009). Some promising crops for production under the organic system are cumin (spice), psyllium (medicine), sesame (oilseed), cluster bean (gum), moth bean (traditional snacks e.g. papad, bhujia), etc.

The low rainfall areas that were fairly untouched from green revolution due to the shortage of water are most suitable for organic farming which promises to be the future evergreen revolution (self-sustainable system) as these areas have the following components which are integral to organic farming:

 

  1. Efficient use of limited water:

    Water is a scarce resource in the low rainfall, However, at many places in the region water along with fertilizers is being used indiscriminately for the production of water demanding crops viz. rice, wheat, cotton, sugarcane, and vegetables. As a result danger of desertification due to various reasons including water logging and salinization is emerging in the region. The use of synthetic fertilizers increases water demand of crop. Contrary to intensive chemical farming, organic farming has been found to improve soil quality and water retention. The water demand can further be reduced by growing low water requiring but high-value crops like spices and legumes.

 

  1. Low fertilizer use-early conversion:

    In this area due to an erratic pattern of rainfall, the rate of fertilizer application is very low (36.4 kg ha-1) as compared to national average of 76.8 kg ha-1. This can be a good opportunity for early and easy conversion into organic farming. According to the priority areas of National Organic Farming Policy, this part of the country comes under the priority I and II, which can facilitate obtaining financial help from government agencies.

 

  1. Diversified farming system:

    Farming systems in the low rainfall regions are highly diversified in nature. They incorporate crops, trees, animals, grasses, etc. and have been scientifically found efficient in nutrient recycling and restoration of soil fertility. In these systems 10-30 trees, ha-1 are available, and 2-5 animals are reared by a farm family. This integrated farming system provides manure, minimizes pest incidence as well as favors organic farming.

 

  1. Rich traditional wisdom:

    Rich traditional wisdom about the restoration of soil fertility and pest control existing in these regions further strengthens and provides the strong basis for organic farming (Sharma and Goyal, 2000).

 

  1. Natural availability of inputs:

    Plants like neem, Pongamia, calotropis, etc. are the best sources of biopesticides and are abundantly available in these areas. Neem plants are available in various densities, and use of neem-based biopesticides has been found effective in pest control in crops of low rainfall areas (Verma and Vir, 1997) under IPM mode. Minerals like rock phosphate, gypsum and lime are available in large quantities. These are good soil ameliorators as well as good nutrients suppliers. Further, the farming systems in low rainfall regions are strongly animal based and subsequently large amount of materials namely urine, dung and bones are available for enhancing agricultural production.

 

  1. Employment opportunities:

    Due to erratic rainfall and limited irrigation facilities, a farming community of the regions remains underutilized during a major part of the year as cropping is possible in rainy season only. Migration of human resources during drought imbalances the development of agriculture as these areas remain no man’s land during about half of the year. Since organic farming is labor intensive and the required inputs are prepared at a local level, ample opportunity is offered by the organic farming for employment and proper utilization of the human resource.

 

  1. Soil improvement:

    Soils in the region have low water holding capacity and are deficient in most of the essential nutrients. The addition of organic matter not only improves the water holding capacity but also enhances the supply of nutrients to plants in a balanced manner.

 

  1. Mitigating effect of climate change:

    Worldwide 90 million tons of mineral oil or natural gas is processed to get nitrogenous fertilizers every year. This generates 250 million tons of CO2  emission. On the contrary, organic farms sequester 575 to 700-1 kg ha CO2  to the soil. Organic farming thus reduces CO2  emission by eliminating synthetic fertilizers and at the same time reduces atmospheric concentration of the gas by storing in the soil, a win-win system (Niggli, 2008). Further, it is estimated that soils with higher humus content could adapt to the adverse effect of climate change.

 

  1. High-value crops:

    These areas have four major export oriented crops namely cluster bean (as guar gum), sesame, cumin and psyllium (isabgol). Total combined export of these crops is about ` 2000 crores year-1. Given the present trends and competitive market, enhancing export of mainly organic produce is a promising possibility for these regions.

 

Quality of organic produce via markets

Production  of  food  in  organic  farming  and  maintaining  quality  is  becoming  a necessity both for international and domestic markets, because:

  1. The demand for organically produced foods is increasing.

 

  1. With the scientific advancement, many of our monopoly crops are being grown by several other countries and quoting lower rates in the international market. For example, cumin was a monopoly crop of India, but now it is being grown by China, Iran, Turkey, and Egypt.

 

  1. In this era of global open economy, domestic consumers are free to buy a quality with low-priced produce from the international market.

 

Therefore for maintaining our monopoly or rather competitiveness for international as well as domestic market, economic as well as quality production is becoming imperative.

 

Low-cost quality produce

 

  1. In an organic production system, no external synthetic chemical is used, and moreover, the emphasis is given on recycling of locally available resources. With this approach cost of production can be reduced up to 60% as compared to conventional chemical farming.

 

  1. There are several examples of experiments and farmers’ experiences which show that due to balanced nutrient supply through organic sources, the quality of organic produce increases many folds regarding aroma, essential oil content, texture, taste and shelf life. Such products fetch a better market price.

 

Other issues for opting organic farming

 

  1. Low and reduced supply of fertilizers:

    To some extent, nitrogenous fertilizers and most of the other fertilizers are imported from various countries. Not only these imported fertilizers but also a supply of nitrogenous fertilizers is decreasing due to changing international scenario. Moreover, most of the fertilizers companies give priority to irrigated areas Punjab, U.P., Haryana, Maharashtra, etc. for supply and rainfed areas are remained short supplied. Therefore, to reduce dependency on imported fertilizers and recurring problem of short supply in rainfed areas, opting organic farming is the only solution.

 

  1. Most suitable for spices and medicinal plants:

    Most of the spices like cumin, fennel, ajwain, fenugreek, etc. are important ingredients of Ayurvedic, allopathic and homeopathic preparations. These medicines are supposed to give to patients, and if these ingredients have residues of pesticides, it may be poisonous instead of curing the patients. Therefore, growing spices and medicinal plants organically is suitable as well as a social option.

Importance of soil organic carbon in organic farming

Role of organic matter in soil

A healthy fertile soil is the basis of organic farming that affects the quality and health of plants. Use of organic matter over time invariably leads to increase in organic carbon level in the soil, which favorably impacts the physical, chemical and biological properties of the soil and enhances the buffering capacity of the soil. These changes have been universally observed in all arable soils and climatic conditions. Consequent to improved soil health, sustainable higher crop production is achieved. Therefore, soil organic carbon is accepted “the basis of good sustainable agriculture.”

Factors affecting soil carbon level

In a natural ecosystem level of soil organic carbon at a given location is a function of:

  1. Climate – primarily temperature and rainfall,
  2. Soil – mainly texture and topography,
  3. Vegetation, and
  4. Time

It tends to establish equilibrium with the ecosystem, but since all the factors except texture are dynamic hence soil organic carbon stock is also dynamic.

Climate

The Wind is an important climatic parameter and causes soil erosion under arid condition. Soil organic carbon (SOC) content in the wind eroded sandy soils is reported 50% less than that in non-eroded sandy loam soils. Temperature and rainfall are known to have a significant influence on organic carbon level in the soil. This is due to their controlling effect on plant growth and microbial activities. Better plant growth provides higher input of carbon to the soil, while higher microbial activities cause greater depletion of soil carbon due to more decomposition of soil organic carbon including the residues. The difference between the magnitude of their individual effect on addition and depletion of carbon determines the net balance of carbon in soil. This concept is universally evident.

As an example, in hot and wet areas of the tropics despite high plant productivity and thus higher input of soil organic matter soil organic carbon levels are low. This low soil carbon status is attributed to high decomposition rates that decompose almost all organic carbon. However, as is broadly acknowledged high rainfall and low-temperature conditions are in general conducive to accumulation of organic carbon in soils, while high temperature and low rainfall conditions are not conducive for the build-up of carbon stock in soil (Table 2).

 Effect of temperature on soil organic carbon within selected moisture belts in India

Area Rainfall (cm) Mean annual temperature(oC) Organic carbon(%)
Dry region 35-75 23-24 0.50+-0.028
Semi-humid region 75-100 27-29 0.54+-0.0.75
Humid region 125-225 12 1.26+-0.18
Per humid region 250-500 14 2.06+-0.49

 

Soil type

 Soil type affects the carbon stock of the soil. In a fertile soil plant productivity and thus carbon input is high resulting in higher level of soil carbon content. Researchers have established that increase in clay content, in general, has a positive impact on soil carbon stock. Accordingly, Alfisols in the arid region, which are rich in clay content (36%) than Entisols and Aridisols, have higher organic carbon content (3.7 g kg-1) than Entisols (1.5 g kg-1) and Aridisols (1.0 g kg-1). Organic carbon content in soils below 300 mm rainfall zones ranges from 0.05-0.2% in coarse textured soils, 0.2-0.3% in medium textured soils and 0.3-0.4% in fine textured soils.

Dhir (1977) has shown that even in the low range of organic carbon (<0.5%) increase in clay content is associated with an increase in organic carbon. One prime reason for the positive relationship between clay content and soil organic carbon content is that clay surface and clay micro-aggregate protect organic materials from decomposition by either holding them tightly as complexes or by physically trapping them; thus, rendering them unavailable to the microorganisms.

 

Vegetation

Although climate and soil are the two important factors governing the choice and growth of a plant in an area, however, the plant itself makes a strong contribution to the status of soil carbon level also. Bhati and Joshi (2007) reported that in an agroforestry system at CAZRI Jodhpur SOC (%) was more under leguminous trees namely Acacia albida (0.179) and Prosopis cineraria (0.165) compared to non-leguminous trees namely Tecomella undulata (0.138) and Ziziphus mauritiana (0.138). Also, less biomass input and more soil disturbance were among the other factors that resulted in a buildup of less carbon in soil under the legume crop mung bean (0.125).

Considering the carbon input in soil, components of the plant both above the ground namely leaf and stem and below the ground namely root is critical. In low rainfall zones, a large volume of carbon gets sequestered through roots especially the tree roots. Planting of trees and grasses in the degraded lands of the arid zone can increase soil carbon stock from 24.3 Pg to 34.9 Pg (Narain, 2008). Pearl millet crop grown under scarce rainfall condition at Jodhpur contributes on an average 700 kg ha-1 dry root biomass in surface 15 cm. The quantity must obviously be much higher under irrigated condition and varies with the crops and management.

 

Time

 Soil organic carbon stock is dynamic. It has clearly been established that both carbon depletion and build up processes are strongly influenced by time. Thus soil carbon status is a time dependent soil quality parameter. It has also been established that while the rate of depletion is a fast process the restoration is relatively a very slow process; and depending on the maximum carbon storage capacity of a soil in a given location and condition including the status of carbon depletion it may sometime take hundred to thousand years to attain equilibrium i.e. when soil is saturated with organic carbon and is left with no capacity to store any more amount of soil organic carbon. All the processes related to depletion and restoration of soil carbon is management dependent.

Management practices

Some management practices such as cultivation, residue burning or removal, and fallowing that involves repeated cultivation to control weed reduce soil organic carbon by increasing decomposition by oxidation or reducing inputs of organic materials to soil or the both.

Management practices that do not favor higher carbon stock:

 

  • Tillage:

    It exposes organic materials to increased oxidation and thus higher loss. The increase in soil erosion also occurs and thus accelerated the loss of SOC.

 

  • Stubble burning/removal:

    Both practices reduce the input of organic matter and thus the buildup of carbon stock. Exposure of unprotected soil surface to rain favors more erosion and thus loss of carbon from the top soil. Burning also causes carbon loss due to heat/high temperature.

 

  • Low cropping intensity/fallowing:

    In low-intensity cropping/fallowing, smaller inputs of organic matter do not favor the buildup of carbon stock. During fallow period repeated cultivation to control weed accelerates the loss of soil organic carbon by processes described above under tillage.

 

Approaches to enhance organic matter in soil

As discussed earlier, climate, soil type, vegetation, time and management practices govern the status of organic carbon in soil. While we do not have control over climate and soil type, we could, however, adopt appropriate vegetation, time and management practices to create a positive balance of organic inputs over the losses. This will enhance carbon level in the soil.

In theory any management practice viz. manure, crop rotation, cultivars and irrigation which leads to large increase in yield should increase soil organic carbon due to increased carbon input resulting from higher biomass production. Also, the productivity increase achieved by crop intensification practices such as double cropping, opportunity cropping, and multiple cropping enhance soil carbon. Conservation agriculture which emphasizes on reduced disturbance to soil to reduce carbon loss, and retention of stubble to increase carbon input is reported to build carbon stock in soil over the time. Various organic materials like manure, compost, biosolids from sewage, etc. are rich in organic carbon. Their use in agriculture especially the organic farming is being encouraged to enhance soil organic level in the soil. The practices that help in the build up of soil organic carbon are:

 

Reduced tillage

It reduces exposure of organic matter to oxidation and thus less loss.

 

  • Stubble retention:

    Stubble retention favors higher input of organic matter and thus the buildup of carbon stock. Increased protection of soil surface from rains favors less erosion and thus less loss of carbon from the top soil. Stubble mulch can enhance biomass production resulting from higher yield and thus more input of organic matter.

 

  • Higher cropping intensity/less fallowing:

    In higher cropping intensity/reduced fallowing input of organic matter is higher, this favors the buildup of carbon stock.

 

  • The input of organic amendments:

    The input of organic amendments viz. compost, worm castings, manure and recycled organic materials enhance carbon stock through direct effect as well as through enhanced production.

 

  • Increase crop yield:

    Use of manures, irrigation, high yielding variety, optimized rotations including the inclusion of legumes in crop rotation all increase crop yield per unit land area and thus higher input of organic matter.


Application of manure

 Since manure is a bulky input, and therefore its method of application is very important specially to reduce the cost of application and effective use in the arid zone where losses may be high due to low soil moisture and high temperature. Therefore, subsurface placement may be the better option. However, very limited studies have been done on the placement of manure. Reiman et al. (2009) found higher corn yield with the placement of manure. In placement operation, the placement device is very important for getting required results that need further studies.

 

Pest Management in Organic Farming

In recent years organic farming has gained much importance as the understanding regarding the ill effects of so-called conventional farming in the general public has increased. People now want to use products which are healthy and free from chemicals and pesticides, and they are ready to pay a little extra for these kinds of products. All this has to be done without affecting the productivity of the crop or the system. In organic systems, the goal is to alter the production system so that pests do not find plants, controlled by natural enemies (biological control), and their damage is kept to a minimum. Vigorous, healthy plants are more able to withstand damage caused by arthropods and diseases.

Therefore, healthy soil and healthy plants are the foundations of organic production. Organic farming production systems adopt agricultural practices which rely on beneficial flora and fauna together with proper soil and crop management to protect and enhance optimal soil health and crop ecology. Practices adopted under organic farming are sustainable and gradually build a system where the majority of insect pests are managed by their natural enemies i.e. the beneficial insects, predators and parasitoids of insect pests.

The general principles of insect pest management in organic production are: use of natural enemies (biological control), cultural practices like crop rotation, intercropping, sanitation, resistant varieties, maintenance of biological diversity or farmscaping (creation of habitat to enhance the chances of survival and reproduction of beneficial organisms), appropriate planting dates, and plant spacing, good soil management practices and use of organic pesticides like botanicals (neem oil, neem cake) and microbial (Bacillus thuringiensis (Bt), pyrethrum, and insect-parasitic fungi (Metarhizium, Beauveria, etc).

 

Beneficial insects

Contrary to popular perception that all insects are harmful and cause damage to plants, animals, and human beings, many of the insects are beneficial and aid in food production by way of pollination and controlling insects which are pests.

 

Pollination

Pollination is one of the most important processes in food production by plants. It is critical for food production and human livelihoods, and many flowering plant species only produce seeds if pollinators move pollen from the anthers to the stigmas of their flowers. Approximately 80% of all flowering plant species are specialized for pollination by animals which are mostly insects. Pollinators are essential for fruit and seed production in many vegetables, fruits, oilseeds and other crops. Pollinators such as bees, birds, and bats affect 35% of the world’s crop production, increasing outputs of 87 of the leading food crops. For human nutrition, the benefits of pollination include not a just abundance of fruits, nuts, and seeds, but also their variety and quality.

Among insects, bees (Hymenoptera: Apidae) are the most important and effective pollinators, but other insects such as wasps, flies, moths, butterflies and beetles also have a major contribution as pollinating species. Vertebrate such as bats, birds, hummingbirds and rodents, squirrels are also important pollinators. In an agroecosystem like organic farms, with a diversity of flowering plants, there is abundance and diversity of pollinators too.

 

Natural enemies

The use of natural enemies to maintain pest populations below damaging levels is known as ‘Biological Control.’ Natural enemies of insects fall into three major categories: predators, parasitoids, and pathogens. Predators catch and eat their prey. Some common predatory arthropods include ladybird beetles, lacewings, syrphid flies, carabid (ground) beetles, big-eyed bugs, and spiders. Parasitoids (sometimes called parasites) do not usually eat their hosts directly. Pathogens are organisms that cause diseases in insects. The main groups of insect disease-causing organisms are insect-parasitic bacteria, fungi, protozoa, viruses, and nematodes. The bacterium Bacillus thuringite sis (Bt) is a well-known microbial control agent that is available commercially. Several insect-pathogenic fungi are used as microbial control agents, including Beauveria, Metarhizium, and Paecilomyces.

 

Predators

The predators search out, attack and eat prey insects. The following predators are common in the arid ecosystem and are abundant at the organic farm.

Ladybird beetles – Coccinellidae (Coleoptera)

 Coccinellid beetles are the best friends of a farmer. They are also called ladybugs. These beetles are conspicuous insects on farms due to their colorful and spotted appearance. They are oval-shaped, about 0.6-0.8 cm long with bright yellow, orange or red wing covers with dark spots or stripes. Most ladybugs voraciously feed on soft-bodied insects such as aphids, white flies, mites and scale insects, and in doing so, they help to protect crops. They go through four stages of development: egg, larva, pupa and adult. Eggs are laid singly but in large numbers on leaves or near insect colonies. The tiny yellow egg hatches in about a week.

Ladybug larvae resemble tiny alligators, with long, pointed abdomens, spiny bodies, and legs that protrude from their sides. After hatching, the ladybug larvae immediately begin to feed. The larvae feed and grow for about a month, and consume hundreds of aphids or other insects during this stage. A hungry ladybug larva can devour 50 aphids per day.

Lacewings – Chrysopidae (Neuroptera)

 Green lacewings are generalist predators and are commonly found in agricultural habitats. Adult green lacewings are delicate soft-bodied insects with four pale green membranous wings, bright golden eyes, and green bodies. Adults are active fliers, particularly during the evening and night and are seen near lights. Adults feed only on nectar, pollen, and aphid honeydew, but their larvae are active predators. Chrysoperla carnea is a common green lacewing. Females lay their tiny, oblong eggs on silken stalks attached to plant tissues. Eggs are green when laid and then darken before hatching. Eggs hatch in 4 days, and larvae develop through three instars before pupating. Larvae, which are pale with dark markings, look like tiny alligators. These are flattened, tapered at the tail, measure 3-20 mm long, have distinct legs, and possess prominent mandibles with which they attack their prey.

Larvae prey upon a wide variety of small insects including mealybugs, thrips, mites, whiteflies, aphids, small caterpillars, leafhoppers and insect eggs. Pupation occurs in loosely woven, spherical, silken cocoons attached to plants or under loose bark. Lacewings pass the unfavorable season as adults, usually in farm waste.

Syrphids – Syrphidae (Diptera)

 Syrphid flies are also known as hover flies as they have a unique ability to hover, suspended in mid-air like helicopters. They quickly fly or dart a short distance, only to hover again, and they can fly backward also. Adults of many syrphid species resemble honey bees and wasps and have yellow and black stripes on their abdomen. Syrphid flies are important pollinators and can be found feeding on different types of flowers in the field. The larvae of these are important predators of aphids, scales, thrips and caterpillars. These insects are common in the arid zone, especially during the winter season. When syrphid larvae populations are high, they may control 70-100% of an aphid population.

The life cycle of hover flies varies from three weeks to nine weeks. The eggs are creamy white, elongated oval and laid singly on leaves, usually in or near an aphid colony. These eggs hatch in two to eight days. The larva is yellowish, legless and blind. It has a typical maggot shape, tapering to a point at the head end and broadly rounded at the rear, with two narrow whitish long stripes on the body (Fig. 5). The larva fastens itself to a leaf or twig when it is ready to pupate. The color of the pupa changes from green to the color of the adult hover fly. Most pupa pass unfavorable season in soil or under fallen leaves.

Ground beetles – Carabidae (Coleptera)

 These predaceous beetles are medium to large, soil-dwelling, often about 8-16 mm long, black or dark red, although some species are metallic blue, brown or green. Most species have a prominent thorax that is narrower than their abdomen. They have long antennae, long legs, are fast runners, and rarely fly and are attracted to lights at night. Carabid adults and larvae feed on soil-dwelling insect larvae and pupae, other invertebrates such as snails and slugs, and sometimes on seeds and organic litter.

The female lays eggs singly on the moist soil surface, and the egg hatches into an elongated larva. Larvae live in farm waste or soil. Larvae are elongate, and their heads are relatively large with distinct mandibles. Most species complete their life cycle from egg to adult in one year. Beetles can hide such as leaf piles, old boards, rotting logs. The beetles secrete a strong bad smelling substance for defense, and this can cause a burning sensation on human skin when the beetles are handled.

Wasps (Hymenoptera)

 A large number of wasps from several families prey on insect pests. Many take their prey, whole or in pieces, back to their mud, soil or paper nests to feed to the immature wasps. These hunting wasps can be important in controlling crop insect pests. For example, the common Polistes paper wasps, when hunting, may thoroughly search plants and feed on caterpillars, often providing substantial control of these insects. Many types of wasps are common in arid zone especially yellow wasps which are good pollinators of fruits like ber (Fig. 7).

Spiders (Arachnida)

 All spiders are predaceous; they eat mainly insects, other spiders, and related arthropods. Some species capture prey in webs, others hunt for insects across the ground or on vegetation and devour them (Fig. 8). Spiders are classified in the arachnid group along with mites. Unlike insects, which have six legs and three main body parts, spiders have eight legs and two main body parts. Most of the spiders are harmless to humans.

 

Parasitoids

Adult parasitoids lay their eggs in, on or near their host insect. When the eggs hatch, the immature parasitoids use the host as food. Many parasitoids are very small wasps and are not easily noticed.

Tachinid flies

 Tachinid flies are an important group of parasitoids. They look like house flies and are grey or brown covered with dark bristles. Adult tachinid flies lay eggs on various caterpillars, beetles, and bugs, usually near the head. The eggs hatch almost immediately, and the young maggots tunnel into their host. After feeding internally for a week or more, the tachinid fly larvae eventually kill the host insect.

Braconid and ichneumonid wasps

 These are a large and diverse group of insect parasites. Some are small and attack small insects such as aphids. Others live in the eggs of various pest insects. Larger parasite wasps attack caterpillars or wood-boring beetles. External evidence of these parasites’ activity is often more obvious than with the tachinid flies. For example, aphids that are parasitized by these wasps are typically small and discolored and called “aphid mummies.” Other braconid wasp species spin conspicuous pupal cocoons after emerging from a host. Small hymenopteran parasitoids are often seen on ber flowers, henna flowers and also on weeds like Pulicularia sp.

Enhancing biodiversity

As discussed earlier, the larval or young stages of many beneficial insects feed on other insects, but the adults of most of the predators and parasitoids of pest insects require nectar and pollen at certain stages of their life for growth and reproduction. A diversified ecosystem with many types of trees, shrubs and small plants provides microhabitats, food sources (prey, nectar, pollen), alternative hosts and shelter for natural enemies and thus encourages their colonization and population build-up. Creation of habitat on farms to enhance the chances of survival and reproduction of beneficial organisms is known as ‘Farmscaping.’ The plant species chosen for this purpose should be such that they do not attract insect pests of the crops chosen for the farm and also the flowering should be in succession so that food is available for beneficial insects round the year.

Plants that have flowers with a good amount of nectar/pollen, like umbelliferae, compositae, and brassicaceae are especially attractive for insects. Flowers which are attractive in color, have small shallow flowers and plants with extra floral nectaries encourage beneficial insects on the farm.

Trees/Shrubs

Ber and henna in the organic farm provide pollen and nectar to a variety of pollinators, predators, and parasitoids besides providing shelter for insects like lacewing. Many lacewing eggs are seen on henna and ber plants. Predatory wasps are observed in good numbers on ber flowers. Calotropis shrubs encourage beneficial insects like coccinellids (Fig. 10) and syrphids. Moreover Calotropis and henna also support populations of prey insects viz., aphids and whiteflies which provide food to predators when the crops are not in the field. Prosopis cineraria and Acacia Senegal trees are also a good source of pollen and nectar and attract many types of pollinators and parasites on the farm.

 

Botanicals

Many plants have insecticidal properties i.e. they are toxic to insects. Botanical insecticides are naturally occurring chemicals (insect toxins) extracted or derived from such plants. They are also called ‘natural insecticides.’ Organic gardeners opt for these insecticides, instead of conventional chemical pesticides. In general, they act quickly, degrade rapidly and have, with a few exceptions, low mammalian toxicity. Neem is a very well-known example of botanical pesticide.

 

Neem

 The well-known tree is common in most agro-climatic zones in India and can be easily grown. Its leaves and seed kernels both have pesticidal properties. Leaf extract in water, a spray of neem seed kernel extract, neem oil and use of oilseed cake in soil are common ways of using neem in organic systems. Neem extracts are a complex mixture of biologically active materials.It is not only active as a feeding deterrent for insects, but it also serves as a repellent, growth regulator, oviposition (egg deposition) suppressant or toxin.

 

Neem oil

It acts as powerful as an antifeedant and insect repellent, oviposition deterrent and ovicidal effect. If eggs are produced, they do not hatch, or the insect larvae are unable to moult properly. Only chewing and sucking insects are affected. Disruption of feeding and breeding gradually results in the decline in the insect population. Neem oil breaks down very quickly and is especially susceptible to UV light. However, neem oil also acts as a systemic insecticide. Although neem oil is not harmful to beneficial, its spray should be done in early in the morning or late afternoon or evening so that it does not affect bees, ladybugs, lacewings, predatory mites, and wasps, etc.

 

Neem leaf extract

 Take one-kilogram fresh green neem leaves, chop them and soak in five liters of water for overnight. Filter and add five liters more water to the filtrate.

 

Neem Seed Kernel Extract (NSKE)

 Collect ripe neem fruits during the season. Take care that the fruits are not soiled or contaminated with fungi as this may damage the quality of the final products prepared. Dry the fruits and store in jute bags. Remove seed coat and pulp from the neem seeds by hand. After depulping and cleaning, dry the neem seeds in the shade on a clean surface with good aeration. Do not make a heap of the seeds. After drying the neem seed up to 11% moisture, store in jute bags, not in plastic bags, in a cool and dry place. If processed properly these neem seeds can be stored for 6-12 months.

For the best results of the extract or oil extraction use within after three months and before eight months of storage. Remove seed coat (decorticate) with the help of mortar and pestle or any mechanical decorticator. Clean the neem kernel and seed coat mixture by winnowing seed coat. Take one kg of clean neem kernel, powder it in such a way that no oil comes out, soak in about 10 liters of water, add 10 ml of pH neutral adjuvant ( a mixture of emulsifier, spreader, etc.) and stir the mixture. Keep the mixture overnight and filter it on the next day with a clean muslin cloth. Put water in the residue and repeat the extraction 2-3 times. Use residue as manure for plants.

 

Spraying of NSKE

The spray of 1.25% to 5.0% (neem kernel w/v) of NSKE is recommended on the crops, lower concentration as a preventive and higher concentration as protective. Use the spray solution on the same day. Spraying should be done covering all plants foliage in the low intensity of sunlight preferably in the afternoon. Its effect remains for 7-10 days.

 

Calotropis leaves

 Calotropis has been traditionally used for its insecticidal effect by farmers especially for controlling termites. In the organic farm extracts of several plants viz., neem, calotropis, and leaves of non-palatable weeds are used as a pesticide for controlling insect pests.

 

Preparation of extracts

 Chop one kilogram fresh leaves of calotropis into small pieces; soak in five liters of water for overnight. Filter and mix one-liter filtrate with nine liters of water, and spray on the crop in the evening as spraying in the evening gives better results.

 

Oilseed cakes

Application of nutrients only through the organic source of fertilizers such as farm yard manure and oilseed cakes has long-term benefits regarding building up of soil organic matter which favors multiplication of microorganisms besides improving the physical properties of soil. Oilseed cakes are a source of valuable major and micro-nutrients essential for optimal crop growth and yield and enrich the arid zone soils which are highly deficient in micronutrients. The utility of neem oil seed cake as a fertilizer as well as a pesticide on many economically important crop species is well known.

Use of farmyard manure and neem seed cakes provide balanced nutrition to plants as compared to urea and other nitrogenous fertilizers, which sometimes make plants more prone to insect pests especially sucking insects, aphids, jassids, whiteflies. The balanced soil conditions and absence of chemical pesticides provides a favorable environment for the development of healthy microflora and fauna in the soil which in turn provides resistance to plants.

 

Tumba seed cake

 Soil amendment with neem seed cake and tumba (Citrullus colocynths) seed cake @ 500 kg per hectare before transplanting reduced infestation of termites and thrips and increased the yield of chilli (Patel and Bhati, 2005). Treated plots had very less damage due to termites which was at par with endosulfan (4% dust 25 kg ha-1) as compared to untreated plots. The incidence of sucking insect pests and apical leaf curl (matha bandhana) was significantly lesser than endosulfan-treated and control plots.

A significant increase in a number of fruits was in the organic soil amendments, and during third picking, it was maximum with the application of neem seed cake (46.7 fruits plant-1) which was double than the number of fruits in plants of control plot (23.1 fruits plant-1). Soil amendment with mustard/castor oil cakes 1000 kg ha-1 was effective in reducing the number of root galls and the population of Meloidogyne incognita (Poonam et al., 2008) in chillies.

 

Crop rotation

 Crop rotation is one of the most effective tools for managing pests and maintaining soil health. The life cycle of pest insects can be discontinued or disrupted by growing crops which are not hosts to the insect pests.

 

Intercropping

 Intercropping encourages biodiversity and increases the effects of natural enemies by providing a nectar source for natural enemies and serves as a habitat for a variety of insects and soil organisms that would not be present in a single-crop environment. It also improves conditions (e.g. moisture, shelter) for ground-dwelling predators.

 

Crop residues

Some amount of crop residues should be left on the farm. During temperature and moisture fluctuations, these provide hiding places for soil predators such as carabid beetles, spiders, and centipedes. The adults of many beneficial insects pass the unfavorable weather conditions in crop residue or farm waste.

 

Bird perches

Bamboo or wooden poles in the crop serve as bird perches where insectivorous birds like mynas, red-vented bulbuls, crows and green bee-eater can rest and look for prey insects.

 

Source-

MLA

“Organic farming in low rainfall areas | agropedia.” agropedia. N.p., n.d. Web. 23 May. 2017 <http://agropedia.iitk.ac.in/content/organic-farming-low-rainfall-areas>.

APA

Organic farming in low rainfall areas | agropedia. (n.d.). Retrieved from http://agropedia.iitk.ac.in/content/organic-farming-low-rainfall-areas

  • Central Arid Zone Research Institute.

 

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