Reversing land degradation through grasses: a systematic meta-analysis in the Indian tropics

Although intensive agriculture is necessary to sustain the world's growing population, accelerated soil erosion contributes to a decrease in the environmental health of ecosystems at local, regional and global scales. Reversing the process of land degradation using vegetative measures is of utmost importance in such ecosystems. The present study critically analyzes the effect of grasses in reversing the process of land degradation using a systematic review. The collected information was segregated under three different land use and land management situations. Meta-analysis was applied to test the hypothesis that the use of grasses reduces runoff and soil erosion. The effect of grasses was deduced for grass strip and in combination with physical structures. Similarly, the effects of grasses were analyzed in degraded pasture lands. The overall result of the meta-analysis showed that infiltration capacity increased approximately 2-fold after planting grasses across the slopes in agricultural fields. Grazing land management through a cut-and-carry system increased conservation efficiencies by 42 and 63% with respect to reduction in runoff and erosion, respectively. Considering the comprehensive performance index (CPI), it has been observed that hybrid Napier (Pennisetum purpureum) and sambuta (Saccharum munja) grass seem to posses the most desirable attributes as an effective grass barrier for the western Himalayas and Eastern Ghats, while natural grass (Dichanthium annulatum) and broom grass (Thysanolaena maxima) are found to be most promising grass species for the Konkan region of theWestern Ghats and the northeastern Himalayan region, respectively. In addition to these benefits, it was also observed that soil carbon loss can be reduced by 83% with the use of grasses. Overall, efficacy for erosion control of various grasses was more than 60 %; hence, their selection should be based on the production potential of these grasses under given edaphic and agro-ecological conditions. The present analysis also indicated that grass must be used as a vegetative strip to maintain soil quality in sloppy arable areas (8.5 Mha) of Indian hilly regions. Similarly, due attention should be paid for establishing grasses in 3 Mha of degraded pasture lands and 3.5 Mha of shifting cultivation areas in India to reverse the land degradation

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Not AvailableALTHOUGH INTENSIVE AGRICULTURE IS NECESSARY TO SUSTAIN WORLD'S GROWING POPULATION , ACCELERATED SOIL EROSION CONTRIBUTES TO A DECREASE IN THE ENVIRONMENTAL HEALTH OF ECOSYSTEMS AT LOCAL , REGIONAL AND GLOBAL SCALE . REVERSING THE PROCESS OF LAND DEGRADATION USING VEGETATIVE MEASURES IS OF UTMOST IMPORTANCE IN THESE ECOSYSTEMS . THE PRESENT STUDY CRITICALLY ANALYSES THE EFFECT OF GRASSES IN REVERSING THE PROCESS OR LAND DEGRADATION USING A SYSTEMATIC REVIEW. THE COLLECTED INFORMATION WAS SEGREGATED UNDER THREE DIFFERENT LAND USE AND LAND MANAGEMENT SITUATION . META- ANALYSIS WAS APPLIED TO TEST THE HYPOTHESIS THAT THE USE OF GRASSES REDUCES RUNOFF AND SOIL EROSION. THE EFFECT OF GRASSES WAS DEDUCED FRO GRASS STRIPO AND IN COMBINATION WITH PHYSICAL STRUCTURES SIMILARLY, THE EFFECTS OF GRASSES WERE ANALYSED IN DEGRADED PASTURE LANDS. THE OVERALL RESULT OF THE META- ANALYSIS SHOWED THAT INFILTRATION CAPACITY INCREASED APPROXIMATELY 2- FOLD AFTER PLANTING GRASSES ACROSS THE SLOPES OF AGRICULTURAL FIELDS.Not Availabl

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Not AvailableHardwickia binata, is an important fodder and timber tree of arid regions. Assessment of its biomass and carbon content is essential, for taking management decisions, and in ecosystem modelling. Seven models namely logistic, Gompertz, Chapman, Hill, Allometric, Linear and Monomolecular were tested for this purpose by using diameter at breast height (DBH). Allometric model (Y = a ×DBHb) was found best performing with AIC value of 12.65. This model was then used to develop biomass equations for different tree components using DBH as independent variable. Developed equations showed high R2 values (0.894 to 0.989). These equations were then used to assess the biomass and carbon stock of H. binata plantations of different age groups. Total biomass of plantations ranged between 63.61 Mg ha−1 (14 years) and 139.55 Mg ha−1 (36 years) with the corresponding carbon stock of 28.39 Mg ha−1 and 63.35 Mg ha−1 which translates into carbon sequestration rate of 1.60 and 2.02 Mg ha−1 a−1, respectively. The developed equations provide a realistic assessment of biomass productivity and carbon stock with low error margin and would thus be very useful in taking suitable management decisions and in ecosystem modelling to explain impact of carbon management to policymakersNot Availabl

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Not AvailableOn farm bio-resource recycling has been given greater emphasis with the introduction of conservation agriculture specifically with climate change scenarios in the mid-hills of the north-west Himalaya region (NWHR). Under this changing scenario, elevation, slope aspect and integrated nutrient management (INM) may affect significantly soil quality and crop productivity. A study was conducted during 2009-10 to 2010-11 at the Ashti watershed of NWHR in a rainfed condition to examine the influence of elevation, slope aspect and integrated nutrient management (INM) on soil resource and crop productivity. Two years of farm demonstration trials indicated that crop productivityand soil quality is significantly affected by elevation, slope aspect and INM. Results showed that wheat equivalent yield (WEY) of improved technology increased crop productivity by ~20-37% compared to the conventional system. Intercropping of maize with cowpea and soybean enhanced yield by another 8-17%. North aspect and higher elevation increased crop productivity by 15-25% compared to south aspect and low elevation (except paddy). Intercropping of maize with cowpea and soybean enhanced yield by another 8-15%. Irrespective of slope, elevation and cropping system, the WEY increased by ~30% in this region due to INM technology. The influence of elevation,slope aspect and INM significantly affected soil resources (SQI) and soil carbon change(SCC). SCC is significantly correlated with SQI for conventional (R2 29 = 0.65*), INM technology (R2 = 0.81*) and for both technologies (R2 30 = 0.73*). It is recommended that at higher elevation. (except for paddy soils) with a north facing slope, INM is recommended for higher crop productivity; conservation of soil resources is recommended for the mid hills of NWHR; and single values of SCC are appropriate as a SQI for this region.Not Availabl

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Not AvailableReduction of inherent structural recalcitrance and improved saccharification efficiency are two important facets to enhance fermentable sugar yield for bioethanol production from lignocellulosic biomass. This study optimized alkaline pretreatment and saccharification conditions employing response surface methodology to improve saccharification yield of jute (Corchorus olitorius cv. JROB-2) biomass. The biomass is composed of cellulose (66.6 %), lignin (19.4 %) and hemicellulose (13.1 %). NaOH concentration exhibited significant effect on delignification during pretreatment. The highest delignification (80.42 %) was obtained by pretreatment with 2.47 % NaOH at 55.8 ◦C for 5.9 h removing 79.8 % lignin and 34.2 % hemicellulose from biomass, thereby increasing cell wall porosity and allowing better accessibility to saccharification enzyme. During saccharification optimization, significant effect was observed for biomass loading, enzyme concentration and temperature. Optimized saccharification condition yielded maximum saccharification (76.48 %) when hydrolysis was per formed at 6.9 % biomass loading with enzyme concentration of 49.52 FPU/g substrate at 51.05 ◦C for 74.4Not Availabl

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Not AvailableGrowth, biomass, carbon storage, and carbon sequestration potential along an age series in Populus deltoides plantations were assessed. The growth rate of diameter at breast height and height was higher in trees of 4 to 7 years and 2 to 5 years, respectively. The total aboveground biomass (AGB) increased with age and reached its maximum (180.2 Mg ha–1) at 11 years of age. Mean carbon concentration in aboveground components varied from 39.7% to 51.7%. Allometric equations were developed to estimate biomass and biomass carbon in different tree components, which had adjusted R squares greater than 94%. Aboveground carbon stocks in P. deltoides increased from 0.5 Mg ha–1 at 1 year to 90.1 Mg ha–1 at 11 years. The carbon sequestration rate (i.e. carbon sequestrated in wood products and by the substitution of biomass for coal) in mature plantations (7–11 years) varied from 5.8 to 6.5 Mg C ha–1 per year. Soil carbon stocks increased with age (1–11 years) from 61.2 to 66.8 Mg ha–1 and decreased with soil depth. Soil carbon stock in different ages of plantations varied from 63.9 to 83.8 Mg ha–1 at 0–30 cm depth, 57.5 to 60.1 Mg ha–1 at 30–60 cm depth, and 55.5 to 59.7 Mg ha–1 at 60–90 cm depth. The amount of total carbon stock (AGB and soil) increased from 64.4 Mg ha–1 at 1 year to 173.9 Mg ha–1 at 11 years. This study recommends P. deltoides planting as a viable option for sustainable production and carbon mitigation.Not Availabl

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Not AvailableGrowth, biomass, carbon storage, and carbon sequestration potential along an age series in Populus deltoides plantations were assessed. The growth rate of diameter at breast height and height was higher in trees of 4 to 7 years and 2 to 5 years, respectively. The total aboveground biomass (AGB) increased with age and reached its maximum (180.2 Mg ha–1) at 11 years of age. Mean carbon concentration in aboveground components varied from 39.7% to 51.7%. Allometric equations were developed to estimate biomass and biomass carbon in different tree components, which had adjusted R squares greater than 94%. Aboveground carbon stocks in P. deltoides increased from 0.5 Mg ha–1 at 1 year to 90.1 Mg ha–1 at 11 years. The carbon sequestration rate (i.e. carbon sequestrated in wood products and by the substitution of biomass for coal) in mature plantations (7–11 years) varied from 5.8 to 6.5 Mg C ha–1 per year. Soil carbon stocks increased with age (1–11 years) from 61.2 to 66.8 Mg ha–1 and decreased with soil depth. Soil carbon stock in different ages of plantations varied from 63.9 to 83.8 Mg ha–1 at 0–30 cm depth, 57.5 to 60.1 Mg ha–1 at 30–60 cm depth, and 55.5 to 59.7 Mg ha–1 at 60–90 cm depth. The amount of total carbon stock (AGB and soil) increased from 64.4 Mg ha–1 at 1 year to 173.9 Mg ha–1 at 11 years. This study recommends P. deltoides planting as a viable option for sustainable production and carbon mitigation.Not Availabl

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Not AvailableRainfall is a prime input of the hydrological cycle and therefore its variability analysis plays a key role in designing of engineering structures and crop planning. The increase in uncertainty of rainfall events may affects the water resources which lead to decrease the production in agricultural sector especially in hill region like Uttarakhand. The present study was based on spatio-temporal analysis of rainfall variation in the state of Uttarakhand, India over the 20th century (1901–2000). Sen’s slope and Mann– Kendall statistics were used to test the trend in annual and seasonal rainfall pattern, and the maximum decrease in monsoon rainfall was observed in Champawat district (2.16 mm year-1) followed by Bageswar (1.82 mm year-1), and Pithoragarh (1.80 mm year-1). Rainfall in winter and postmonsoon seasons also decreased in all the districts but the changesobserved were not significant (p>0.05). Pettitt’s testwas employed to know the most probable change year forseasonal and annual rainfall trend. After 1986, asignificant declining trend over the year was observed in annual, post-monsoon and monsoon rainfall showed at the probability levels of 0.052, 0.085 and 0.059, respectively. Whereas, after 1964, a declining trend during winter rainfall Was observed but the change was found to be nonsignificant (p= 0.452). To know the periodicity of rainfall pattern, Wavelet analysis was done and observed an increasing frequency of annual and monsoon extreme rainfall events with stronger periodicity of 2–8 years in the recent decades.These findings will be helpful for the policy makers for optimal water allocation and also for making scientific managementstrategies for constructions of engineering structures, utilization of rain water for agriculture such as land preparation and sowing, and other uses.Not Availabl

Applying Analytic Hierarchy Process for Identifying Best Management Practices in Erosion Risk Areas of Northwestern Himalayas

Despite the growing importance of soil and water conservation and watershed development projects as an approach to rural development and natural resource management, there has been relatively little research on devising site-specific best management practice (BMP) to check the soil erosion losses within permissible limits, especially in hilly regions. For a sustainable watershed management programme and implementation, site specific BMPs assume importance and hold the promise of making conservation planning and watershed management simpler and more effective. The study was attempted to develop a methodology to obtain BMPs, aiming to reduce the erosion losses in erosion risk areas of the northwestern Himalayas by employing Analytic Hierarchy Process (AHP). The AHP technique was employed to prioritise the potential technologies and select the BMP suitable for a particular land area. The prioritization of technologies was performed with four criteria viz. soil erosion resistance, cost, benefit, maintenance and environment friendliness of conservation measures. The soil erosion scenario of the study area located in the northwestern Himalayas was generated with each selected measure in a SWAT model using DEM, land use maps, a soil map and climate data of the study area. Then, the resultant erosion scenario of the conservation measures was compared and used for the AHP analysis. However, other criteria were assessed based on the judgement of a group of experts as well as farmers. In this study, four conservation measures, viz. Bench Terraces (BT), Vegetative Barrier (VB), Contour Farming (CF) and Zero Tillage + Live Mulch (ZL), were considered for BMP selection. Three scenarios, viz. experts’ judgement, farmers’ opinions and combined expert and farmer opinion, were analyzed to uncover the BMP for the different zones. The result revealed that experts and farmers unanimously preferred ZL as a BMP because of its low-cost implementation value and lower maintenance requirement while significantly controlling the erosion level as well as being environment friendly. The BT was the second most preferred technology for the study area. However, BMP was recommended for different zones having high to very severe erosion (soil loss > 10 t/ha/yr). Therefore, ZL was recommended for the areas with low altitude, whereas BT was recommended for the areas having high slopes because of its high capability for erosion control in the high slopping area. The methodology will act as a useful strategy for decision makers to prioritize the technology and recommend the best management for any region after considering suitable criteria. Future work may consider more criteria for inclusion to thus recommend the technology for a region in a more realistic way

Applying Analytic Hierarchy Process for Identifying Best Management Practices in Erosion Risk Areas of Northwestern Himalayas

Despite the growing importance of soil and water conservation and watershed development projects as an approach to rural development and natural resource management, there has been relatively little research on devising site-specific best management practice (BMP) to check the soil erosion losses within permissible limits, especially in hilly regions. For a sustainable watershed management programme and implementation, site specific BMPs assume importance and hold the promise of making conservation planning and watershed management simpler and more effective. The study was attempted to develop a methodology to obtain BMPs, aiming to reduce the erosion losses in erosion risk areas of the northwestern Himalayas by employing Analytic Hierarchy Process (AHP). The AHP technique was employed to prioritise the potential technologies and select the BMP suitable for a particular land area. The prioritization of technologies was performed with four criteria viz. soil erosion resistance, cost, benefit, maintenance and environment friendliness of conservation measures. The soil erosion scenario of the study area located in the northwestern Himalayas was generated with each selected measure in a SWAT model using DEM, land use maps, a soil map and climate data of the study area. Then, the resultant erosion scenario of the conservation measures was compared and used for the AHP analysis. However, other criteria were assessed based on the judgement of a group of experts as well as farmers. In this study, four conservation measures, viz. Bench Terraces (BT), Vegetative Barrier (VB), Contour Farming (CF) and Zero Tillage + Live Mulch (ZL), were considered for BMP selection. Three scenarios, viz. experts’ judgement, farmers’ opinions and combined expert and farmer opinion, were analyzed to uncover the BMP for the different zones. The result revealed that experts and farmers unanimously preferred ZL as a BMP because of its low-cost implementation value and lower maintenance requirement while significantly controlling the erosion level as well as being environment friendly. The BT was the second most preferred technology for the study area. However, BMP was recommended for different zones having high to very severe erosion (soil loss > 10 t/ha/yr). Therefore, ZL was recommended for the areas with low altitude, whereas BT was recommended for the areas having high slopes because of its high capability for erosion control in the high slopping area. The methodology will act as a useful strategy for decision makers to prioritize the technology and recommend the best management for any region after considering suitable criteria. Future work may consider more criteria for inclusion to thus recommend the technology for a region in a more realistic way