Factors determining the adoption of laser land leveling in the irrigated rice–wheat system in Haryana,India

Laser land leveling has been increasingly adopted in the irrigated rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system in the state of Haryana (India), located in the north-western Indo-Gangetic Plains. Still, many farmers have applied it to only a fraction of their land. In this study, we used data collected from 621 farm households in Haryana and applied a double-hurdle model for assessing the factors that determine the adoption and intensity of laser-leveling technology. The results show that large land holders are more likely to laser level their farm land; however, we found a negative association between land holdings and the proportion of laser-leveled land. Information about technology through farmer-to-farmer communication and through private traders, participation in agricultural training and membership in local agricultural institutions increased both the likelihood and the intensity of adoption. Our findings call for a closer collaboration among the various stakeholders, specifically to promote farmer-to-farmer communication through increased participation in local institutions and increase the rate of adoption of laser leveling technology.     

Silvopastoral systems improve carbon stocks at livestock ranches in Tabasco,Mexico

Silvopastoral systems have great potential for storing carbon because of carbon assimilation in tree woody biomass, carbon input through litterfall and below-ground carbon turnover. In this study, we quantified and compared the carbon stocks at livestock ranches in Tabasco, Mexico, containing either scattered trees in grazing pastures (STP) or grass monocultures. Sampling plots were randomly established at each ranch where the above- and below-ground carbon stocks, carbon input from litterfall, grass production and arboreal biomass growth were measured. We found that silvopastoral systems stored an average of 257.45 Mg ha⁻¹ of soil organic carbon (SOC) compared to 119.17 Mg SOC ha⁻¹ at grass monoculture ranches (to 30 cm depth); silvopastoral systems also stored 44.64 Mg C ha⁻¹ in wood biomass; and, grass monocultures had greater cumulative grass biomass production. Overall, it is concluded that livestock ranches in Tabasco, Mexico, with scattered trees in grazing pastures stored 58.8% more carbon than those grass monocultures, with carbon stocks of 327.01 Mg C ha⁻¹and 134.47 Mg C ha⁻¹, respectively. The results are useful for land management decision making for sustainable livestock systems framed in the Sustainable Development Goals (SDGs).     

Water quality under intensive banana production and extensive pastureland in tropical Mexico

The effects of intensive banana production with high mineral‐fertilizer application and of extensive pastures were compared regarding water quality in a lowland region of SE Mexico. We monitored NO$ _3^- $ , NO$ _2^- $ , and PO₄^3– concentrations in groundwater (80 m depth), subsurface water (5 m depth), and surface water (open‐ditch drainage) at monthly intervals for a one‐year period. Irrespective of the land use, the NO$ _3^- $ concentrations in all water bodies were lower than the threshold value for drinking water and aquatic life. Particularly in areas with intense banana production, the NO$ _2^- $ contents in water exceeded the safety thresholds for drinking water of 1.0 mg L^–1 (WHO, 2006) and aquatic ecosystems of 0.2 mg L^–1 (OATA, 2008). Water from pastureland showed significantly higher PO₄^3– concentration than that from the banana plantation, indicating a high risk of eutrophication. There is a need to provide recommendations for optimal time and amount of N application in commercial banana production and for limitation of P inputs in pasturelands to avoid further contamination of water bodies.     

Cu(II) Biosorption and Competitive Studies in Multi-ions Aqueous Systems by Arthrobacter sp. Sphe3 and Bacillus sphaericus Cells: Equillibrium and Thermodynamic Studies

Arthrobacter sp. Sphe3 and Bacillus sphaericus cells were used for Cu(II) biosorption. The effect of contact time, biosorbent dose, equilibrium pH, temperature and the presence of other ions on the efficiency of the process were extensively studied. Optimum pH value and biomass concentration were determined at 5.0 and 1.0?g/l, whereas contact time was found to be 5 and 10?min for Arthrobacter sp. Sphe3 and Bacillus sphaericus biomass, respectively. Equilibrium data fitted very well to Freundlich model (R ²?=?0.996, n?=?2.325, K _f?=?8.141) using Arthrobacter sp. Sphe3. In the case of B. sphaericus, a Langmuir adsorption model [R ²?=?0.996, Q _max?=?51.54?mg-Cu(II)/g] showed to better describe the results. Potentiometric titration and Fourier transform infrared (FTIR) spectroscopy showed that amine, carboxyl and phosphate groups participate in Cu(II)-binding. The calculated thermodynamic parameters indicated the spontaneous and feasible nature of Cu(II) biosorption on both biosorbents. Selectivity of Cu(II) biosorption was examined in binary and multi-ions systems with various anions and cations which are commonly found in municipal and industrial wastewater. A specificity towards Cu(II) was observed in binary mixtures with Cl^-, CO ₃ ^-2 , NO ₃ ^- , SO ₄ ^-2 , PO ₄ ^-3 , Mg⁺² and Ca⁺², and As(V) with the maximum uptake capacity remaining constant even at high competitive ion??s concentrations of 200?mg/l. Desorption studies showed that Cu(II) could be completely desorbed from Cu(II)-loaded Arthrobacter strain Sphe3 and B. sphaericus biomass using 1.0 and 0.8?M HCl, respectively, and both bacterial species could be effectively reused up to five cycles, making their application in wastewater detoxification more attractive.     

Effect of Rhizobium inoculation on growth,modulation, and nitrogenase activity of some legume tree species

An experiment was conducted to study the effect of inoculation of Rhizobium suspension in Albizia procera (Roxb.) Benth, Albizia lebbeck (L.) Benth, and Leucaena leucocephala (Lam.) De Wit. seedlings grown in sterilized and non‐sterilized soil media. Control treatments were maintained by non‐inoculation. Inoculation response was observed strong in sterilized and modest in non‐sterilized soil when compared to respective control treatments. Increase in height was found 105.07%, 63.42%, and 109% higher in sterilized soil and 52.1%, 68.6%, and 95.8% in non‐sterilized soil for Albizia procera, Albizia lebbeck, and Leucaena leucocephala, respectively, after a period of 4 months. Nodule number increased up to 10.27 and 3.51 times in Albizia procera, 11.47 and 4.3 times in Albizia lebbeck, and 7.22 and 2.9 times in Leucaena leucocephala due to inoculation in sterilized and non‐sterilized soil media respectively. Significant increase in nodule dry weight and nitrogenase activity was also recorded in both sterilized and non‐sterilized soil for all the species tested. Nitrogenase activity per plant per hour was recorded 68.75,11.58, and 13 times higher in sterilized and 6.7,5.53, and 3.38 times higher in non‐sterilized soil over control for the species respectively after 4 months. In the tree species tested the inoculation of Rhizobium showed higher productivity, modulation and nitrogenase activity than control suggesting the idea that application of Rhizobium suspension greatly enhances plant growth, modulation, and nitrogenase activity.     

Climate change adaptation,greenhouse gas mitigation and economic profitability of conservation agriculture: Some examples from cereal systems of Indo-Gangetic Plains

Achieving sustainability of the cereal system in the Indo-Gangetic Plains(IGP)of India under progressive climate change and variability necessitates adoption of practices and technologies that increase food production,adaptation and mitigation in a sustainable way.This paper examines conservation agriculture(CA)from the perspective of:(i)increased yield and farm income,(ii)adaptation to heat and water stresses,and(iii)reduction in greenhouse gas(GHGs)emissions.The analyses and conclusions are based on the literature and evidences from a large number of on-station as well as farmers’field trials on CA in the cereal systems of IGP.Our analyses show that CA-based system substantially reduces the production cost(up to 23%)but produces equal or even higher than conventional system;thereby increasing economic profitability of production system.CA-based production systems also moderated the effect of high temperature(reduced canopy temperature by 1–4°C)and increased irrigation water productivity by 66–100%compared to traditional production systems thus well adapting to water and heat stress situations of IGP.Our continuous monitoring of soil flux of CO2,N2O and CH4 revealed that CA-based rice-wheat systems emit 10–15%less GHGs than conventional systems.This is the first time that CA and its components are synthesized and analyzed from food security-climate change nexus.From this holistic analysis,we suggest that wide-scale promotion of suitable CA practices by integrating into national agriculture development strategy is a way forward to address food security,climate change adaptation and mitigation challenges faced by present agriculture.     

Diurnal and seasonal variations on soil CO2 fluxes in tropical silvopastoral systems

This study aimed to quantify the dynamics of soil CO₂ fluxes in two silvopastoral systems based on Leucaena leucocephala, one associated with Panicum maximum (L + P) and another with Cynodon plectostachyus (L + C). We measured CO₂ fluxes fortnightly during the dry and rainy seasons in the morning and the afternoon, with an infrared gas analyzer. Simultaneously, we measured soil temperature, soil moisture, ambient temperature, and relative humidity. Soil CO₂ fluxes ranged from 6.0 ± 0.14 to 6.1 ± 0.12 µmol CO₂/m²/s but no statistical differences were observed between systems. Soil CO₂ flux in the L + P was 12.5% higher in the rainy season compared with the dry season but the season did not affect the fluxes in L + C. Regarding the diurnal variation, CO₂ fluxes were 17.6%–34.8% higher in the morning compared with afternoon measurements. Soil moisture and temperature were higher in L + C, but the ambient temperature and relative humidity showed no statistical differences between systems. In both systems, soil temperature was greater in the afternoon, while the soil moisture and relative humidity were greater in the morning. The diurnal variation of soil CO₂ fluxes in silvopastoral systems correlated positively with soil temperature and ambient temperature, but negatively with relative humidity. We concluded that soil CO₂ fluxes did not vary between silvopastoral systems but respond differently to the seasons. The results have important implications on the establishment and management of Leucaena-based silvopastoral systems for the mitigation of soil CO₂ fluxes from extensive livestock production lands.     

Comparison of Carbon Stocks Between Mixed and Pine-Dominated Forest Stands Within the Gwalinidaha Community Forest in Lalitpur District, Nepal

Forests play an important role in the global carbon cycle as both a source and sink of carbon. The carbon stock in a forest is affected by climate, tree species and forest management. The community forestry program of Nepal has been successful in reviving degraded forest patches in the Mid-hills but there is a lack of information whether mixed or pine plantations store more carbon. This study estimated and compared carbon stocks in mixed and pine-dominated forest stands within the Gwalinidaha Community Forest of Lalitpur District, Central Nepal. Carbon components considered include tree biomass carbon, root biomass carbon, litter biomass carbon and soil organic carbon. Total carbon stock of the forest is estimated to be 2,250.24 tons with average carbon stock of 166.68 tons/ha. Total carbon stock per hectare was found to be higher in the pine-dominated forest as compared to mixed forest due to the larger tree biomass although the litter carbon and soil organic carbon estimates are higher in the latter. The Community Forestry of Nepal has a huge potential for carbon storage and the pine-dominated forest has a greater carbon stock than mixed forest.     

Elevated carbon dioxide and nitrogen supply affect photosynthesis and nitrogen partitioning of two wheat varieties

The response of wheat to elevated carbon dioxide concentration (e[CO₂]) is likely to be dependent on nitrogen supply. To investigate the underlying mechanism of growth response to e[CO₂], two wheat cultivars were grown under different carbon dioxide concentration [CO₂] in a chamber experimental facility. The changes in leaf photosynthesis, C and N concentration, and biomass were investigated under different [CO₂] and N supply. The result showed an increase in photosynthesis under e[CO₂] at all N level except the one with the lowest N supply. Furthermore, a significant decrease in g_s and Tr for both the cultivars was also observed under e[CO₂] at all N levels. A considerable increase in WUEi was observed for both the cultivars under e[CO₂] at all N levels except for the lowest concentration one. Therefore, the study shows that a stimulation of plant growth under e[CO₂] to be marginal at higher N supply.