Litterfall, decomposition and nutrient release patterns of different tree species in Taran Taran district of Punjab, India

The present investigation was attempted to assess the leaf litter production, decomposition rate and amount of major nutrient return in Populus deltoides, Eucalyptus tereticornis, Tectona grandis and Pyrus pyrifolia based agroforestry land use systems in Taran Taran district which falls in the north western agro-climatic zone of thePunjab state, India. The litter production in selected tree species was quantified using litter traps and decomposition pattern of leaf litter was investigated by litter bag technique. Litterfall in the selected tree species varied significantly (5 % level of significance) during different months of the study period. Among the four species, P. deltoides exhibited highest leaf litter production (7.8 tons/ha) followed by T. grandis (1.83 tons/ha) and E. tereticornis (1.77 tons/ha) whereas, lowest leaf litter production was observed in P. pyrifolia (0.34 tons/ha). The present study also showed that temperature as compared to rainfall play a significant (5 % level of significance) role in litter decomposition. In case of P. pyrifolia, P. deltoides and T. grandis decomposition take place 100 per cent, 98 per cent and 99 per cent respectively after 10 months whereas in E. tereticornis 87.7 per cent leaf decomposed after 10 months. The nutrients percentage through litter fall was maximum of nitrogen (2.27 %) followed by potassium (1.90 %) and phosphorous (0.32 %). Maximum and minimum N input through leaf litter was in P. deltoides (2.27 %) and P. pyrifolia (1.15 %). The K input (%) was maximum in leaves of T. grandis (0.32) and minimum in E. tereticornis (0.21). The maximum input of P (%) through leaf litter was in P. deltoides (1.90) whereas, minimum value was observed in E. tereticornis (1.27). Tree based agroforestry land use systems improve soil nutrient status as compared to traditional wheat and paddy based land use systems under this region of Punjab. Therefore tree based land use systems need to be promoted over the traditional field crops for realizing better environmental benefits in this region

Society issues, painkiller solutions, dependence and sustainable agriculture

Mahatma Gandhi listed seven blunders of humanity: Wealth without work, Pleasure without conscience, Commerce without morality, Worship without sacrifice, Politics without principles, Knowledge without character, and Science without humanity. Here I tackle three major issues, climate change, financial crisis and nation security, to disclose weak points of current remedies, and to propose sustainable solutions. Global warming and the unexpected financial crisis will undoubtedly impact all nations. Treating those two critical issues solely by painkiller solutions will fail because only adverse consequences are healed, not their causes. Therefore all sources of issues must be treated at the same time by enhancing collaboration between politicians and scientists. Furthermore, the adverse consequences of globalisation of markets for energy, food and other goods have been overlooked, thus deeply weakening the security of society structures in the event of major breakdowns. Therefore dependence among people, organisations and nations must be redesigned and adapted to take into account ecological, social and security impacts. Solving climate, financial and security issues can be done by using tools and principles developed by agronomists because agronomy integrates mechanisms occurring at various space and time levels. Agriculture is also a central driver for solving most society issues because society has been founded by agriculture, and agriculture is the activity that provides food, renewable energies and materials to humans. I present a to-do list summarising the major practices, principles and benefits of sustainable agriculture based on about 100 recently-published review articles. The practices are agroforestry, allelopathy, aquaculture, beneficial microorganisms and insects, biofertilisation, biofuels, biological control, biological nitrogen fixation, breeding, carbon sequestration, conservation agriculture, crop rotation, cover crops, decision support systems, grass strips, integrated pest management, intercropping, irrigation, mechanical weed control, mulching, no tillage, organic amendments, organic farming, phytoremediation, precision agriculture, seed invigoration, sociology, soil restoration, suicidal germination, terracing, transgenic crops, trap crops, and urban agriculture

Speciation of phosphorus in a fertilized, reduced-till soil system: in-field treatment incubation study

Citation: Khatiwada, Raju, Ganga M. Hettiarachchi, David B. Mengel, and Mingwei Fei. “Speciation of Phosphorus in a Fertilized, Reduced-Till Soil System: In-Field Treatment Incubation Study.” Soil Science Society of America Journal 76, no. 6 (2012): 2006–18. https://doi.org/10.2136/sssaj2011.0299.Phosphorus management in reduced-tillage systems is a great concern for farmers. Conclusive positive results of deep-banding P fertilizers compared with broadcast application and the chemistry of reduced-tillage systems remain unclear. Knowledge of the dominant solid P species present in soil following application of P fertilizers and the resulting potential P availability would help us understand and efficiently manage P in reduced-tillage systems. The objective of this research was to study the influence of placement (broadcast vs. deep-band P), fertilizer source (granular vs. liquid P), and time on the reaction products of P under field conditions. Changes in soil pH, resin-extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 wk and 6 mo after P application at a rate of 75 kg ha−1 to a soil system that was under long-term reduced tillage. Resin-extractable P was lower for broadcast treatments compared with deep-band treatments for both time periods. Resin-extractable P was greater in the liquid P-treated soils than in the granular P-treated soils. Speciation results showed that granular P fertilizers tended to form Fe–P-like forms, whereas liquid forms remained in adsorbed P-like forms in the soil 5 wk after application; moreover, speciation results showed granular P fertilizers precipitated less when deep-banded. During the 6-mo period following application, reaction products of broadcast granular, broadcast liquid, and deep-band granular fertilizers transformed to Ca-phosphate or mixtures of Ca-, Fe- and adsorbed-phosphate-like forms, whereas deep-band liquid P remained as mainly adsorbed P-like forms. Deep-banding of P would most likely provide a solution that is both agronomically and environmentally efficient for reduced-till farmers

The role of macro-aggregation in regulating enzymatic depolymerization of soil organic nitrogen

Extracellular enzymatic depolymerization of polymeric organic nitrogen (PON) is a rate-limiting step in N mineralization. However, enzymatic accessibility to PON might be regulated by physical occlusion of the PON resulting from the architectural packing of soil minerals during aggregate formation. To examine the extent to which enzymatic accessibility to PON is regulated by soil aggregation, we put forward a new approach involving the comparison of relationships between potential N depolymerase activity (protease and β-glucosaminidase; as an estimate of the potential to produce depolymerized products) and net N mineralization (as a bioassay for actual low molecular weight dissolved ON production) in aggregated and corresponding disaggregated soil. Soils were sampled from grassland (GL) and arable land (AL), separated by dry sieving into fractions (4.75-2, 2-0.25 and 0.25-0.063 mm) and fractions mixed (4:4:1 by mass, respectively) to obtain constructed aggregated soils. Corresponding disaggregated soils were prepared using a mortar and pestle. This procedure mainly disrupted the 4.75-2 mm (large macro-aggregate) fraction. Disaggregation significantly promoted (p<0.05) net N mineralization rates by 1.3 times and 1.5 times in GL and AL soil, respectively. When net N mineralization - potential N depolymerase relationships for GL were examined, a greater slope parameter for disaggregated compared to aggregated soil (p=0.001; ANCOVA) quantified the extent to which this promoted N mineralization could be attributed to disruption of macroaggregate-increased enzymatic accessibility to PON. For AL, which had low protease and β-glucosaminidase activity, promoted N mineralization rate could not be attributed to increased protease + β-glucosaminidase accessibility to PON reflecting a possible role for other N depolymerases and/or osmolyte/lysate effects. By proposing how differences between mineralization-depolymerase relationships for soils differing in aggregation status might, with assumptions, be interpreted to identify the role of physical occlusion in protection of PON, we give new insight on the regulation of enzymatic depolymerization by physical protection through macro-aggregation for soils from contrasting land use

Soil conservation issues in India

Despite years of study and substantial investment in remediation and prevention, soil erosion continues to be a major environmental problem with regard to land use in India and elsewhere around the world. Furthermore, changing climate and/or weather patterns are exacerbating the problem. Our objective was to review past and current soil conservation programmes in India to better understand how production-, environmental-, social-, economic- and policy-related issues have affected soil and water conservation and the incentives needed to address the most critical problems. We found that to achieve success in soil and water conservation policies, institutions and operations must be co-ordinated using a holistic approach. Watershed programmes have been shown to be one of the most effective strategies for bringing socio-economic change to different parts of India. Within both dryland and rainfed areas, watershed management has quietly revolutionized agriculture by aligning various sectors through technological soil and water conservation interventions and land-use diversification. Significant results associated with various watershed-scale soil and water conservation programmes and interventions that were effective for reducing land degradation and improving productivity in different parts of the country are discussed

Stabilization of organic C in an Indo-Gangetic alluvial soil under long-term manure and compost management in a rice–wheat system

The nature of carbon input to soil, its transformation to soil organic matter (SOM), and the degree of protection from decomposition are important for long-term persistence of SOM. The effect of exogenous addition of organic matter on SOM build-up is well known; however, changes in quality vis-à-vis composition of added organic matter have been less investigated. It is necessary to ascertain the form under which C accumulates and how the composition of added organic matter influences the stabilization of soil organic C (SOC). Changes in composition of SOM were studied by fractionating the soil into coarse (cPOC; >250 µm) and fine particulate organic C (fPOC; 53–250 µm) and mineral-associated organic C (MinOC; <53 µm) and measuring the acid non-hydrolyzable C (NHC) as well as mineralizable C following repeated applications of farmyard manure (FYM), rice straw compost (RSC) and vermicompost (VC) in a rice (Oryza sativa L.)–wheat (Triticum aestivum L.) system field experiment. Addition of organic amendments for 10 years significantly increased SOC stocks and the increase was greatest with RSC (12.2 t ha−1) followed by FYM (9.1 t ha−1), and lowest with VC (8.5 t ha−1), compared with solitary application of NPK. The C accumulation in separated pools was influenced by the chemical composition of the organic source. Compost applications accumulated C preferentially in the MinOC pool, whereas the FYM accumulated a greater proportion of C as POC, particularly as fPOC. The differences were attributed to the lower C/N ratio and higher lignin content of RSC than FYM. The RSC application increased NHC stocks to a significantly greater extent than FYM and VC, indicating recalcitrance of the accumulated C. This was substantiated by the significantly lower C mineralization potential of RSC-amended soils compared to the FYM- and VC-amended soils. The results showed that addition of compost, besides leading to C build-up, improved C stabilization by imparting recalcitrance to SOC