Impact of Cattle Grazing on Selected Environmental Variables in Pasture-Based Livestock Production System

Livestock production system has been developed to meet the increasing demand for ruminant products in Malaysia, however, few studies have focused on the assessment of the impact of such production system on the environmental variables such as soil, vegetation and surface water. With increasing demand for livestock products which resulted in the development of livestock production system, quantification and understanding of the environmental impacts of livestock production are necessary prerequisites for any effective planning to enhance environmental quality. This study aims to assess the impacts of short-term (2-year) heavy and long-term (33-year) moderate grazing by cattle on the quality of soil, vegetation and surface water in communal native and commercial improved tropical pasture ecosystem at both the farm and catchment scales. The study was conducted at the Universiti Putra Malaysia Livestock Section, about 20 km south of Kuala Lumpur, Malaysia. Two study sites, the Ladang 2 farm (3º 00’ 28"N; 101º 42’ 10"E) and the TPU catchment (2º 58' 53"N; 101º 43' 38"E), represented a native and improved pastures, respectively. Water samples from a year-round monitoring of streams in the pastures with cattle grazing and ungrazed exclosure were analyzed for water quality parameters of EC, DO, pH, NH3-N, COD, TSS, Fecal Coliform (FC), and E. coli. Soil chemical characteristics such as pH, EC, OC, TN, AP, exchangeable cations, and heavy metals (Cd, Pb, Cu, Cr, Fe, Zn, and Mn) were analyzed. Infiltration rate, bulk density, penetration resistance, moisture content and porosity were determined to assess alterations in soil physical properties. A combination of both systematic and randomized method was used to measure pasture vegetation and invasive species. Root morphological and distribution characteristics were measured using soil coring approach. Water quality data were analyzed with the multivariate analysis of variance, multivariate statistical techniques and the Harkins’ index. Soil chemical and physical properties and root morphological data were analyzed with the repeated measures analysis of variance. The multivariate analysis of variance was used to analyze pasture vegetation and invasive species data. The results showed that the streams of the TPU catchment were classified as classes II and I in the grazed and ungrazed pastures, respectively. Streams in both the grazed and ungrazed sites were classified as class II in ‘Ladang 2’ farm. Significant difference between the grazed and ungrazed treatments was observed for water quality variables of TSS, COD and FC at the Ladang 2 farm. DO, BOD, pH, EC, TSS, COD, NH3-N, FC and E. coli varied significantly between the grazed and ungrazed pasture in the TPU catchment. The study also revealed that the moderate grazing led to higher soil pH, EC, AP and Mg+2 and lower TN, OC, Ca+2 and K+ at the improved pasture. Higher levels of pH, EC, OC and lower concentrations of AP, TN, Ca+2 and Mg+2 were observed at the native pasture. Moderate grazing had significant effect on heavy metal concentrations in soils, but heavy grazing did not lead to a significant accumulation of heavy metals in the soils. Contrary to the heavy grazing, moderate grazing had no negative impacts on soil physical properties. Moderate grazing increased grasses regrowth rate and herbage mass yield; while heavy grazing had no significant effect on those characteristics. Moderate grazing affected the invasive species population adversely; however heavy grazing provided relatively desirable condition for their establishment and infestation. Mean root diameter, surface area and volume densities were not affected by moderate grazing in the improved pasture. However, root surface area and mass densities were affected at heavily grazed native pasture. Grass roots were significantly affected by heavy grazing at native pasture, but unaffected by moderate grazing at the improved pasture. The results indicated that cattle grazing affect the surface water in pasture ecosystem adversely. Cattle grazing effects on soil chemical characteristics depend on the type of elements, which may increase or decrease over time. Soil heavy metals content can increase in pastures where cattle have been grazing for a long-term. Moderate grazing can influence pasture production positively and decrease the invasive species. Pasture plant roots were not adversely affected by either short-term heavy or long-term moderate grazing intensities. Keywords: Water quality, Vegetation cover, Invasive species, Root morphology, Soil chemical properties, Soil physical properties, Heavy grazing, Moderate grazin

Cattle grazing effect on Mimosa pudica L. in tropical pasture system

Mimosa pudica is the most abundant and problematic invasive species in tropical pastures. This study investigates the effects of two cattle grazing systems, long-term moderate grazing (LTG, 2.7 animal unit/ha/yr for 33 years) and short-term heavy grazing (STG, 5 animal unit/ha/yr for 2 years) compared with ungrazed exclosure pasture on the invasion of M. pudica and its relationship with herbage production in tropical pasture. M. pudica and pasture production were concurrently sampled four times at the end of grass growing period at both grazed and ungrazed pastures. Mean density of M. pudica was 56% greater (P0.05) between the STG pasture and ungrazed exclosure. Mean importance value (IV) of M. pudica in the LTG pasture was 46% lower (P0.05) to the density, IV and dry matter (DM) of M. pudica in either pasture system. An insignificant negative relationship was found between the density and DM of M. pudica with pasture production. In contrast, a positive but insignificant relationship was observed between %IV of M. pudica and pasture production in both pasture sites. The LTG system had adverse effect on M. pudica population, whereas STG system supplied relatively desirable conditions for M. pudica establishment and infestation

How cattle grazing influences heavy metal concentrations in tropical pasture soils

This study investigates the impact of short-term (1.5-year) heavy and long-term (33-year) moderate grazing intensities on the heavy metal concentrations in soils of tropical pastures. The concentration of heavy metals (Cd, Fe, Mn, Cu, Cr, Pb, and Zn) was determined in the Livestock Section of University Putra Malaysia, Selangor, Malaysia. The heavy metal concentrations in the soil were not affected (P>0.05) by shortterm heavy grazing intensity. The concentrations of Fe, Mn, and Zn were significantly affected (P≤0.05) by long-term moderate grazing or soil depth and by the interaction between them. The Cu concentration in soil was only affected (P0.05) by sampling depth or their interaction. The concentrations of Fe, Mn, Cu, and Zn in long-term moderately grazed pasture soil were 127.9, 194.8, 54.8, and 39,900% higher, respectively, than ungrazed pasture. Soil Fe, Mn, and Zn concentrations were significantly higher (P<0.05) in surface (0-10 cm) than subsurface (10-20 cm) soils. Results suggest that the excreta of grazing cattle can be an important source of heavy metals in intensively managed pastures in the long-term. However, metal concentrations were maintained within the normal range and were not high enough to be dangerous from the toxicological point of view

Impacts of livestock grazing on selected soil chemical properties in intensively managed pastures of Peninsular Malaysia

This study investigates the impacts of short-term (1.5-year) heavy (SHG) and long-term (33-year) moderate (LMG) grazing intensities on the chemical properties of soil in the tropical pasture ecosystems. Two pastures with different grazing intensities and two ungrazed pastures were sampled at the varied depths of 0-10 and 10-20 cm in the Livestock Section of Universiti Putra Malaysia (UPM), Selangor, Malaysia. The EC and pH values in both the moderately and heavily grazed pastures were higher than the ungrazed ones. Meanwhile, the total carbon (TC) in the surface soil of the grazed pastures was 63% and 57% higher than the ungrazed pastures in the LMG and SHG pastures, respectively. The concentration of total nitrogen (TN) was not affected (P > 0.05) by livestock grazing. The concentration of available phosphorus (AP) in the surface soil and grazed pasture was significantly greater than the sub-surface soil and ungrazed pastures in the LMG pastures. The AP concentration in the grazed pasture and surface soil was 62.2% and 68.4% less than the ungrazed pasture and subsurface soil in the SHG pasture, respectively. It was found that the concentration of exchangeable cations (Ca+2, Mg+2, and K+) was affected by grazing. In particular, the concentration of exchangeable cations in both the moderately and heavily grazed pastures was also observed to be less than the ungrazed ones, except for Mg+2 in the LMG pasture. These results indicate that the impacts of livestock grazing on soil chemical properties were almost limited to the surface soil. After 33 years of moderate grazing, greater values were found for pH, EC, AP, and Mg+2 whereas lower values were stated for TN, TC, Ca+2, and K+. As compared to the ungrazed control, the concentrations of AP, TN, Ca+2, Mg+2, and K+ decreased after 1.5 years of heavy grazing

Multivariate statistical techniques for the assessment of seasonal variations in surface water quality of pasture ecosystems

This study investigates the applicability of multivariate statistical techniques including cluster analysis (CA), discriminant analysis (DA), and factor analysis (FA) for the assessment of seasonal variations in the surface water quality of tropical pastures. The study was carried out in the TPU catchment, Kuala Lumpur, Malaysia. The dataset consisted of 1-year monitoring of 14 parameters at six sampling sites. The CA yielded two groups of similarity between the sampling sites, i.e., less polluted (LP) and moderately polluted (MP) at temporal scale. Fecal coliform (FC), NO3, DO, and pH were significantly related to the stream grouping in the dry season, whereas NH3, BOD, Escherichia coli, and FC were significantly related to the stream grouping in the rainy season. The best predictors for distinguishing clusters in temporal scale were FC, NH3, and E. coli, respectively. FC, E. coli, and BOD with strong positive loadings were introduced as the first varifactors in the dry season which indicates the biological source of variability. EC with a strong positive loading and DO with a strong negative loading were introduced as the first varifactors in the rainy season, which represents the physiochemical source of variability. Multivariate statistical techniques were effective analytical techniques for classification and processing of large datasets of water quality and the identification of major sources of water pollution in tropical pastures

EVALUATION AND MAPPING OF RANGELANDS DEGRADATION USING REMOTELY SENSED DATA

The empirical and scientifically documents prove that misuse of natural resource causes degradation in it. So natural resources conservation is important in approaching sustainable development aims. In current study, Landsat Thematic Mapper images and grazing gradient method have been used to map the extent and degree of rangeland degradation. In during ground-based data measuring, factors such as vegetation cover, litter, plant diversity, bare soil, and stone & gravels were estimated as biophysical indicators of degradation. The next stage, after geometric correction and doing some necessary pre-processing practices on the study area’s images; the best and suitable vegetation index has been selected to map rangeland degradation among the Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI), and Perpendicular Vegetation Index (PVI). Then using suitable vegetation index and distance parameter was produced the rangelands degradation map. The results of ground-based data analysis reveal that there is a significant relation between increasing distance from critical points and plant diversity and also percentage of litter. Also there is significant relation between vegetation cover percent and distance from village, i.e. the vegetation cover percent increases by increasing distance from villages, while it wasn’t the same around the stock watering points. The result of analysis about bare soil and distance from critical point was the same to vegetation cover changes manner. Also there wasn’t significant relation between stones & gravels index and distance from critical points. The results of image processing show that, NDVI appears to be sensitive to vegetation changes along the grazing gradient and it can be suitable vegetation index to map rangeland degradation. The degradation map shows that there is high degradation around the critical points. These areas need urgent attention for soil conservation. Generally, it shows that the most parts of rangelands in studying area have been degraded. So conservation priorities on degraded rangelands have been recognized based on current degradation