Dab Grass Utilization And Rangeland Degradation And Overgrazing In Pakistan
Fodder crops play important part in the agricultural economy of developing countries by making accessible inexpensive source of feed for livestock. Sultan et al., (2007) recommended that there is a requisite of 13.5 and 110.3 m tons of crude proteins and total digestible nutrients to conserve average livestock. Pakistan is undersupplied by 40% and 80% in forage and concentrates feed, correspondingly (Pasha, 1998). Furthermore the present feed resources are only supply 62% and 74% of requisite crude protein (CP) and total digestible nutrients, accordingly in resulting low productivity of livestock in the country (Sarwar et al., 2009).
In view of the fact that the health and production of livestock count on the nutritional value of existing forage, it is, consequently, crucial for the stockmen and range managers to comprehend the nutritional aspect of forage to maintain sufficient growth and reproduction of animals (Ganskopp and Bohnert, 2001). Various studies have evaluated the nutritional dynamics of forage in natural rangelands (Khan et al., 2002; Islam et al., 2003; Nasrullah et al., 2013; Khan et al., 2005) and in cultivated fodder species (Ashraf et al., 1995). Previous research have pointed out that the nutritional value of forage alter with season, rainfall, type of soil and age of the plants that influence health of grazing animals and palatability (Ganskopp and Bohnert, 2001).
Holecheck et al. (1998) stated high crude protein content in growing forage in comparison to dormant stage. Important factors that influence palatability of a plant species as a feed are degree of maturity, morphological and chemical nature, relative abundance of related species, growth stage, approachability to plants/sites seasonal availability and climate. Animal factors include disparity preference for forage species, age, hunger of animal, general health and stage of pregnancy (Kababia et al., 1992). It has been commonly noticed that sheep usually prefer grasses and forbs more than shrubs; although goats prefer shrubs (Khan, 1996). Migongo-Bake and Hansen (1987) suggested that in East Africa, sheep feed generally consist of more than 50% grasses through all seasons, whereas shrub constituent of their diet likely to raise during dry seasons. Vallentine (1990) reported that goats used up 5% forbs, 25% grasses and 70% browse through different seasons. Kababia et al. (1992) reported that goats utilized 79 to 86% dry matter of bushes in winter, spring and summer. Nyamangara and Ndlovu (1995) observed that feed choice of animals diverse with season.
Dab grass is quoted by Holm et al. (1979) as a “crucial” weed in Pakistan and a “frequent” weed in Egypt and Iraq. It is amongst the unfavorable weeds of crops in Yemen. Once entrenched, it can extend very extensively by rhizome and rule in various climatic conditions. Even though prevailed to very dry conditions, it spread well on the boundaries of irrigated areas and in orchards anywhere it can grow severe infestations that are not easy to get rid of. This might also cause a menace to sensitive habitats in the United States (Al-Kouthayri and Hassan, 1998).
Rangelands
Rangelands cover up more than 40% of the earth’s land region. They are traditionally specified by native plant communities, frequently associated with wildlife and/or domestic grazing, and managed by ecological relatively agronomic methods (Society for Range Management 2014). Rangeland ecosystems are existing on all continents, excluding Antarctica, and they significantly impart to related socio-economic systems. There is general consensus that climatic situation are varying rangeland ecosystem operations and characteristics (Polley et al., 2013). Mostly of these rangelands are located in vegetation biomes like grasslands, deserts, shrub lands and savannas. These lands are frequently particularized by arid climate that show evidence of little rainfall, large daily and seasonal temperature fluctuations (Vetter et al., 2006). The rangelands of Pakistan demonstrate a vast diversity of species composition, yield, structure and eventually their capability to maintain livestock production (Mohammad et al., 1985). The rangelands are extremely significant from environmental point of view since they offer vegetation cover, protection for soil, which also corroborate imperishable economic production of feed for animals. Particularly browse plants (shrubs and tree foliage) alongside grasses make up one of the inexpensive sources of feed for animals in numerous parts of the world. Generally the browse species have the benefit of maintaining their nutritive value and greenness during the dry season when grasses dry up and decline in both quantity and quality (Devendra, 1990; Kibon et al., 1993). Rangelands, which constitute about 65% of the total area of Pakistan, are degrading due to extreme climatic conditions, unplanned grazing, mismanagement in the utilization of water resources and deforestation (Mohammad, 1989). The herbaceous vegetation of these rangelands only flourishes in the monsoon season, accordingly livestock herds show pitiable health and produce very poor yield of meat and milk. These problems are common everywhere in the world where arid or semiarid rangelands exist. Therefore, developing countries like Pakistan face similar situation in their rangeland’s health and productivity (Ahmad and Hasnain, 2001).
In general, the quality of a diet for grazing ruminants depends upon the species present in the range, the amount of forage available and the nutritional quality of the plant species. The more arid the site, the more common drought deciduousness and the less common is ever greenness. During dry period, fodder trees and shrubs play an important role in meeting part of the nutritional requirement. Fodder quality, specifically its nutritive chemical constituents, is of great importance for animal feeding and its impact on performance and production. Rangelands of Pakistan sustain thirty million herds of grazing animals that provide 400 million US $ to annual export income (Anon., 2006). In Pakistan, small ruminants obtain more than 60% of their feed necessities from arid and semi-arid rangelands (Khan et al., 1990). Previous policies have always supported the crops production over livestock, leading in the misuse of lands having economically ineffectual productive potential. Livestock sector play very significant role because it provides various services for humankind like milk and meat, which are vital components of our diet. Livestock occupies a key position in the rural economy of Pakistan for improving the living standard of small resource peoples (Khan et al., 2005).
Rangeland degradation and overgrazing
Rangeland degradation is a universal concern, disturbing not only pastoralists who depend on healthy rangelands for existence but also others who experience hydrological disturbances, commodity scarcity and dust storms (Harris, 2010). The main causes for rangeland degradation are low carrying capacity, unscientific livestock management, excessiveness of unpalatable species, change in climate, and disturbance of soil by small mammals. Overgrazing is a major land problem in arid and semi-arid areas, together with conversion of lands to cultivated farms and because of spatial and temporal variability; it is very difficult to quantify (Landsberg and Crowley, 2004). The rangelands of Pakistan are in the process of deterioration due to extreme climatic conditions, unplanned grazing, prolonged droughts, mismanagement in the exploitation of water resources and deforestation. The efficiency of Pakistan rangelands is very poor and it is not achievable to make use of them without upgrading interventions; though grazers and nomadic peoples are still using these rangelands, which are providing 40-50% forage demand of their animals (Mohammad, 1989). The reasonable use of rangelands is imperative for the improvement of national economy. Pakistan is a sub-tropical country, that possess vast semi-arid and arid tracks of land, covers over 68 million hectares (Majeed et al., 2002).These enormous natural resources of Pakistan are not superintend by scientific measures and currently, only 10-15% of their concrete potential is being acknowledged (Ali et al., 2001).
During summer season, weather is immensely rigorous and harsh; certain xeric plant species tolerate but experience high grazing pressure and bring about fractional eradication (Arshad et al., 2008). Subsequently, the palatable species are declining and unpalatable species with reduced nutritious properties are becoming plentiful. Uninterrupted raise in human population for livelihood and multiplying number of livestock is adding towards the desertification (Abdullah et al., 2013).
Habib et al. (2016) conducted country level assessment of feed accessibility and requirement for livestock in Pakistan. Accessibility of feed component was evaluated from the official crop production tables while feed demands of livestock species were predicted from the standard tables published by US National Research Council. The result showed that indigenous feed resources were less for livestock and poultry requirements. The supply and demand break for dry biomass, crude protein (CP) and metabolizable energy (ME) were 19.4%, 37.2% and 38.0%, correspondingly. Crop residues were the prime source comprising 58.8% of the total feed supply, while fodder and grazing shared 23.8% and 9.2%, respectively. Grains and by-products contributed 8.2% to the feed supply. In effort to fill this gap, large quantities of oilseed meals were imported mostly for the poultry sector. Maize was the foremost feed grain used in poultry and ruminant rations, and they mutually utilized 79% of the country’s total maize produce. On the basis of estimated speedy expansion in poultry, dairy and feedlot farming in Pakistan, the feed gap will additional broaden and this assures future center on well-organized and rigorous consumption of the local conventional and nonconventional feed resources.
Distribution of Dab grass
Dab grass is a grass readily available throughout Potohar region majorly on dry places. Its cover in any area shows presence of soil moisture in deep layers. Xeric conditions of soil are easily encountered by Dab grass by penetrating deep roots in more depth layers of soil. The length of roots of Dab grass is 8 times more than its above ground part (Chaghtai et al., 1989). Based on floristic composition Dab grass was identified as dominant specie with constancy % of 74 and 60 (Malik et al., 2006). Another finding by Shabbir et al., 2006 revealed that Dab grass as roadside vegetated perennial grass with 5.9% relative frequency. His findings indicated the relative frequency (RF) of Dab grass in different sectors of Islamabad in sector. So it’s obvious from above findings that Dab grass can be easily accessible to local farmers throughout the year.
Dab grass utilization
Dab grass can be used as fodder alternate owing to the reasonable crude protein content of 6-7% in the leaves (Fakhireha et al., 2010). Dab grass is a C4 perennial grass from tribe Eragrosteae, family Poaceae. It is a local grass in coastal and interior deserts (Pandeya and Pandeya, 2002) of Iran, India, China, Pakistan, Central Asia, Middle East, and northern Africa (Bor, 1960). According to Cope, 1982, this grass is native to the Sudan region, from Northern Africa (Morocco to Somalia), Sicily, and Cyprus through the Middle East to Central Asia, Pakistan, and India. Cattle browse its pre-bloom leaves (Joshi and Bhoite 1988).
In the Arabian Peninsula, the species has been reported in Oman (Ghazanfar, 1992) Saudi Arabia (Chaudhary, 1989), UAE (Jongbloed, 2003) and Yemen (Wood, 1997). In the UAE, the species was found at Kalba in the emirate of Sharjah (Jongbloed, 2003). Dry fodder, which is about 85% of the total food utilized by livestock, imparts significantly in producing livestock in areas where freshwater supply is limited. Production, nutrition levels or grazing value, productivity, quality, and palatability of Dab grass are being investigated. Dab grass is a low palatable grass that and is low in digestible. Incorporation of this grass with existing feed sources may bridge the gap between supply and demand during scarcity periods. Whereas average amount of protein in the animal diet is nearly 8%- 10% (Oanh, 2002). It’s healthier to graze Dab grass in May, because at this stage, it has more vegetative growth. Gulzar et al. (2007) also described that Dab grass comprises the maximum nutritious value in the mid of May. This grass has relatively high protein content and could be a good fodder. Dab grass is a drought and salt-tolerant C4 grass with a intense, sturdy rhizome which enables as exceptional sand-binder. It is routinely not considered as a fodder but is consumed by mixing with cereals especially in Afghanistan.
Nidaa et al., 2017 evaluated the native conventional knowledge to determine the value of various fodder grasses to refine their use to feed livestock in Central Punjab. She used the snowball technique to categorize key informants who had pertinent knowledge about different grasses in the study area. Semi-structured questionnaires, face-to-face interviews and site visits were adopted for unfolding the fodder grasses. On the whole, 53 grasses were explained with ethno botanical evidence concerning their uses for fodder, ethno veterinary and other purposes in which Dab grass was described in relative abundance as group A grass which is not only the most abundant but also the most palatable forages to all ruminants. The reported data need to be validated for nutritional and health benefits. According to the study ruminants of Central Punjab Pakistan were supplied on a variegated range of wild grasses. Dab grass belongs to subfamily chloridoides locally called as Khusa or Dab. Its aerial part is majorly palatable to cattle and buffalo. From studies it was found that Dab grass is being mixed with feed and free grazing too. Dab grass is used to cure digestive disorders and dysentery as ethno veterinary use. Its Focal person Count (FC) was 76 while its Relative Frequency Citation (RFC) was found to be 0.555
Ali et al. (2016) studied two halophytic grasses (Panicum antidotale and Desmostachya bipinnata) for their potential to surrogate conventional cattle fodder in the diet of cattle. Four trials were carried out in which cow calves were given diets comprising both grasses alone or in mixture with wheat and maize. Weight gain in animals fed diets subsidized with halophytes was usually at par with or in few cases marginally better than those on conventional fodder. For instance, P. antidotale increased the calf weight around 15% when used as green and 8% in case of hay. Feeding Berseem (Trifolium alexandrinum, 15% crude protein) as the only resource of concentrate in a diet containing Dab grass sustained weight only for about 6-7 weeks after which it started to reduce. Supplementing the diet with a usual concentrate was subsequently desirable to reinstate weight gain. Halophytes as green/hay/concentrate were as high-quality as conventional fodder regarding dressed meat. The protein content of meat was showing rising trend when replacing conventional fodders with halophytes, particularly 20% protein was superior in meat when Prosopis juliflora pods and Manilkara zapota were utilized as concentrate and P. antidotale as hay in diet.
Nasia et al. (2013) conducted a study at National Agricultural Research Centre, Islamabad to find out impacts of supplementation of low palatable grasses with urea, molasses and Effective Microorganisms (EM) on chemical composition and digestibility in goats. Heteropogon Contortous (HC) and Desmostachya bipinnata (DB) were used and the combinations were grass + 4% molasses, grass + 4% urea, grass + 4% urea + 4% molasses, grass + 4% urea + 1:100 EM, grass + 1:100 EM + 4% molasses, grass +1:100 EM + 4% molasses + 4% urea. Proximate analysis of samples was conducted. Crude protein content of mixtures enhanced as compared with sole grasses. Digestibility of HC supplemented with urea, molasses and EM in a variety of combinations was also studied in growing goats. The utmost digestibility of DM in goats was recorded in HC + 4% urea + 4% molasses treatment (85.51%) followed by HC + 4% urea (78.57%) and HC + 4% urea + 4% molasses + 1:100 EM (78.00%).
