Soil loss hinders the restoration potential of tree plantations on highly eroded ravine slopes

Journal of Soils and Sediments - Soil erosion and loss threatens vast tracts of agricultural and non-agricultural land, worldwide. High soil erosion severely affects establishment of vegetation via...     

Effect of manures and fertilizers on soil physical properties,build-up of macro and micronutrients and uptake in soil under different cropping systems: a review

Combined application of manures and fertilizers played a pivotal role in the improvement in soil physico-chemical properties, macro and micronutrients distribution and their transformations under different cropping systems. Based on a cropping system, the different levels of manures and fertilizers were used to study improvement in physico-chemical properties of soil. The aim was to explore the appropriate application of organic manures and inorganic fertilizers for improved sustainable yields of a cropping system. Intensive cropping systems lead to N, P, K, Zn, Cu, Fe, and Mn deficiencies in surface and subsurface soil, which could be refreshed with combined application of manures and fertilizers. The application of manures and fertilizers controls the pH and electrical conductivity of soil. Moreover, manures and fertilizers showed improvement is soil physical conditions viz. bulk density, particle density, porosity, and water holding capacity etc. Manuring coupled with fertilization helped to great extent for macro and micronutrient transformations in the soil. Under these transformations, the soil solution and water soluble component (fractions/pools) of soil is enriched with macro and micronutrients. There was a consistent declining trend of DTPA-extractable Zn, Cu, Fe, and Mn in the sub-surface soil in comparison to the surface layer, which may be ascribed to increase in pH with increase in depth and decrease of organic matter with depth. Similarly, manures reduced the concentration of residual macro and micronutrients in soil. Recently, integrated nutrient management system (INMS) is gaining importance vis-a-vis maintaining the soil fertility with conjunctive use of chemical fertilizers plus organic manures.     

Mobilization of seed reserves pretreated with H2O2 during germination and establishment of sunflower seedlings under salinity

Abstract

Several studies have shown hydrogen peroxide (H₂O₂) as a metabolic messenger that increases plant tolerance to various stress conditions. However, little is known about its effect on the mobilization of seed reserves in the establishment of seedlings. Thus, this study aimed to evaluate the effect of pretreatment with H₂O₂ in salt-tolerance and mobilization of reserves during the germination of seeds and establishment of sunflower seedlings. Seeds were pre-imbibed for 24?hr in solutions containing: deionized water (control); H₂O₂ (1?mM); NaCl (100?mM). Subsequently, seeds were distributed on germitest paper, moistened with deionized water or saline solution (100?mM NaCl). In seedlings not pretreated with H₂O₂, the salinity increased Na⁺ and Cl^? ions contents and reduced the growth of sunflower seedlings. However, pretreatment of seeds with H₂O₂ reduced the negative effect of salinity, promoted an increase in salt-tolerance by the reduction of Na⁺ and Cl^? uptake, lower energy cost for osmoprotection by compatible solutes accumulation, and by the higher equilibrium in the mobilization of the cotyledon reserves for the development of the embryonic axis.     

Phytotoxicity evaluation and response of wheat to agro-industrial waste composts

A greenhouse experiment was conducted in loamy sand soil to compare the effects of agro-industrial waste composts on yield and nutrient uptake by wheat. The raw materials of agro-industrial wastes and chemical fertilizers were used as controls. The yields were significantly higher with agro-industrial waste composts compared with their raw materials. Compost-fertilized grain yields were increased by 118% with poultry waste compost and by 97% with chemical fertilizes compared with unfertilized control. Agro-industrial waste composts applied with NK (recommended dose) fertilizers, except distillery effluent compost, produced a wheat grain yield comparable with that obtained with NPK (recommended dose) fertilizers, indicating a net saving of 100% of P fertilizer. Application of agro-industrial waste composts significantly increased NPK uptake by wheat and improved the post-harvest NPK status of soil compared with addition of their raw materials. Up to 60 days of composting, severe suppression of tomato seed germination was observed, which improved thereafter in all the composts. Our results suggest that the germination index >70% may be accepted as an indicator for disappearance of phytotoxic substances.     

Evaluation of maturity and stability parameters of composts prepared from farm wastes

A composting experiment was carried out to study changes in physical [color, odor, temperature, organic matter (OM) loss], chemical [C:N ratio, water-soluble organic carbon (C_w):organic N (N_org) ratio, NH₄ ⁺-N and NO₃ ^?-N, humic acid (HA):fulvic acid (FA) ratio, humification index (HI) and cation-exchange capacity (CEC):total organic carbon (TOC) ratio)] and biological [seed germination index (GI)] parameters to assess compost maturity and stability over a period of 150 days. Five composts were prepared using a mixture of different farm wastes with or without enrichment of N, rock phosphate (RP) and microorganism (MO) inoculation. All the composts appeared to change to a granular and dark grey color without foul odor, and attained a constant temperature with no measurable changes (ambient level) at 120 days of composting. Correlation analysis showed that the optimal values of the selected parameters for our experimental conditions are as follows: organic matter loss > 42%, C:N ratio < 15, HA:FA ratio > 1.9, HI > 30%, CEC:TOC ratio > 1.7 and C_w:N_org ratio < 0.55. Composts enriched with N + RP or N + RP + MO matured at 150 and 120 days, respectively, whereas composts without any enrichment or enrichment with N or RP + MO did not mature even at 150 days of composting.     

Chemical and microbiological parameters for the characterization of maturity of composts made from farm and agro-industrial wastes

Bioconversion of farm wastes with agro-industrial wastes into enriched compost is an important possibility in need of research. In this article, changes in chemical and microbiological parameters were evaluated to determine the maturity of composts prepared from mixture of farm and agro-industrial wastes over a period of 150 days. Seven different composts were prepared by using a mixture of different farm wastes with or without enrichment with rock phosphate (RP), agro-industrial wastes and the inoculation of microorganisms. As composting proceeded, the organic C, water-soluble C (WSC), bacterial and fungal counts decreased, whereas total N, P, electrical conductivity (EC) and actinomycetes count increased gradually. Our results suggest that WSC <1%, C:N ratio < 20, neutral pH and a decrease in bacteria and fungal counts, along with an increase in actinomycetes count and stability at the end of composting, may be accepted as an indicator of compost maturity. Changes in organic C, EC, total N and P concentrations over time also proved to be reliable indicators of the progress of the composting process for establishing stability and compost maturity. Addition of RP, agro-industrial wastes and inoculation of microorganisms showed potential in improving the N and P contents of the composts.     

Sodium chloride stress on organic constituents of Sesuvium portulacastrum L., a salt marsh halophyte

Certain organic constituents, amino acids, protein, proline, glycinebetaine, sugars, and starch in the leaves of Sesuvium portulacastrum, which was grown under varying levels of sodium chloride (NaCl) was determined. Total amino acids lowered at increasing levels of NaCl while the protein content increased moderately up to 600 mM and thereafter increased and decreased, respectively; however, 600 mM level of NaCl significantly differed from the untreated control plants. The concentration of total sugars declined with the increasing levels of exogenous addition of NaCl up to 600 mM. Starch content increased significantly up to 600 mM NaCl and thereafter declined slightly. Proline and glycinebetaine contents were accumulated with the corresponding increase of salinization.     

Mapping quantitative trait loci (QTL) for grain size in rice using a RIL population from Basmati × indica cross showing high segregation distortion

Grain size is one of the three productivity related traits in rice and hence a major target for genetic improvement. Since understanding genetic variation in grain size between Basmati and indica genotypes is important for rice improvement, a recombinant inbred population was developed from a traditional aromatic cultivar ‘Basmati 370’ and a non-aromatic indica genotype ‘IRBB60’. This population was phenotyped in two locations for grain length (GL), grain breadth (GB), GL/GB ratio (LBR) and grain weight (GW). Though the RIL population reported in the current study exhibited segregation distortion (SD) for 54 % of the markers, they were utilized in analysis using an appropriate statistical package, PROC QTL in the SAS environment. Interval mapping revealed a total of 15 QTLs for GL, seven for GB, 15 for LBR and two for GW. Among them 13 were not reported earlier and thus novel. For a known major QTL identified in the study, GW8 for GB, a PCR based functional marker was designed and validated. This is the first report wherein a very high proportion of markers (>50 %) exhibiting SD have been successfully used for QTL mapping.