A long-term field experiment was conducted to design and implement alternative production systems with increased resource use efficiency, productivity and to determine the effect of tillage systems and mineral fertilizers on soil organic carbon patterns. This experiment intended to evaluate the effects of these management strategies on soil structural formation and structural stabilization of a sandy loam soil. The shift from puddled -transplanted rice on the flat land to raised bed systems affects the productivity and resource use efficiency of the rice-wheat system. Therefore, the potential benefits and constraints of tillage crop residue practices need to be quantified on short to long-term basis, optimum layouts and management systems to maximize yield and efficiency. Due to lesser energy input and higher output T3 ZT with 6tha -1 residue retained had 20% and 5% higher energy use efficiency than T7 CT and T6 PRB with 6tha -1 residue retained. Undisturbed soil samples were collected from the 15 to 100 cm soil layer in the field grown with wheat to assess SOC, bulk density, C restoration rate, C sequestered, C sequestration efficiency (%) and crop yield. However, at the end of the 18 years period, SOC was 25% greater with T6 than T7, 16% greater with T4 than T1, and 17% higher with T2 than T7. Average SOC concentration of the control treatment was 0.54%, which increased to 0.65% in the RDF treatment and 0.82% in the RDF+FYM treatment and increased enzyme activities, which potentially influence soil nutrients dynamics under field condition. Compared to F1 control treatment the RDF+FYM treatment sequestered 0.28 Mg C ha -1 yr -1 whereas the NPK treatment sequestered 0.13 Mg C ha -1 yr -1 . As tillage intensity increased there was a redistribution of SOC in the profile, but it occurred only between ZT and PRB since under CT, SOC stock decreased even below the plow layer. Increased SOC stock in the surface 50 kg m -2 under ZT and PRB was compensated by greater SOC stocks in the 50-200 and 200-400 kg m -2 interval under residue retained, but SOC stocks under CT were consistently lower in the surface 400 kg m -2 . Over the last 18 years, CT lost 0.83 ±0.2 kg of C m -2 while ZT gain 1.98 ±0.3 and PRB gain 0.97 ±0.2 kg of C m -2 in the 1200 kg of soil m -2 profile. These findings suggest that carbon sequestration can be improved if treatments T4 or T6 are used in lieu of T7, respectively.

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Soil organic carbon (SOC) and its fractions (labile and non-labile) including particulate organic carbon (POC) and its components [coarse POC and fine POC], light fraction organic carbon (LFOC), readily oxidizable organic carbon, dissolved organic carbon (DOC) are important for sustainability of any agricultural production system as they govern most of the soil properties, and hence soil quality and health. Being a food source for soil microorganisms, they also affect microbial activity, diversity and enzymes activities. The content of OC within WSA followed the sequence: medium-aggregates (1.0-0.25 mm and 1.0-2.0 mm)> macroaggregates (4.76-2.0 mm)> micro-aggregates (0.25-0.053 mm) >large aggregates (4.76 mm) >silt+ clay fractions (<0.053 mm). The highest levels of MBC were associated with the 1.0-2.0 mm aggregate size class. The Cmic/Corg was greatest for the large macro-aggregates regardless of tillage regimes. The tillage treatments significantly influenced soil aggregate stability and OC distribution. Higher MWD and GMD were observed in plowing every 2 years (2TS), plowing every 4 years (4TS) and no plowing (NTS) as compared to plowing every year without residue (T). With increasing soil depth, the amount of macro-aggregates and MWD and GMD values were increased, while the proportions of micro-aggregates and the silt+ clay fraction were declined. The OC concentrations in different aggregate fractions at all soil depths followed the order of macro-aggregates>micro-aggregates>silt+ clay fraction. In the 0-5 cm soil layer, concentrations of macro-aggregate-associated OC in 2TS, 4TS and NTS were 14, 56 and 83% higher than for T, whereas T had the greatest concentration of OC associated with the silt+ clay fraction in the 10-20 cm layer. Tillage regimes that contribute to greater aggregation also improved soil microbial activity. Soil OC and MBC were at their highest levels for 1.0-2.0 mm aggregates, suggesting a higher biological activity at this aggregate size for the ecosystem. Compared with CT treatments, NT treatments increased MBC by11.2%, 11.5%, and 20%, and dissolved organic carbon (DOC) concentration by 15.5% 29.5%, and 14.1% of bulk soil, >0.25 mm aggregate, and <0.25 mm aggregate in the 0−5 cm soil layer, respectively. The portion of 0.25-2 mm aggregates, mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates from ST and NT treatments were larger than from CT at both 0-15-and 15-30-cm soil depths. Positive significant correlations were observed between SOC, labile organic C fractions, MWD, GMD, and macro-aggregate (0.25-2 mm) C within the upper 15 cm. The arylsulfatase, β-glucosaminidase and α-glucosidase activities showed a significant increase in the enzyme activities due to crop rotations in comparison to continuous mono-cropping. The activities of chitinase, leucine aminopeptidase and tyrosine aminopeptidase) in the topsoil layer were higher under conservation agriculture (CA).Moreover, compared with CT, the ZT and FIRB treatments significantly increased nitrifying [Gn] and denit...

Exploiting the production potential of high yielding rice varieties through agronomic management is one of the alternatives to feed the ever growing population. For this, fertilizers from different sources and modern planting techniques have contributed substantially to the spectacular increase in rice yield and to improve soil properties. In order to study the effect of planting techniques and integrated nutrient management in rice. A field experiments was conducted at Crop Research Centre of Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut (Utter Pradesh) during Kharif 2017. The experiment was laid out in split plot design with three replications. The treatment consisted of three planting techniques (P1-conventional puddled transplanting (CT-TPR), P2-wide raised beds transplanted rice (WB-TPR) and P3-reduced till transplanted rice (RT-TPR) and ten integrated nutrient management (F1-control, (no fertilizer), F2-RDF (150-60-40 kg NPK/ha), F3-75%RDF + FYM 5 t/ha, F4-75% RDF + FYM 5 t/ha + Zn, F5-75% RDF + FYM 5 t/ha + BF, F6-75% RDF + FYM 5 t/ha +BF + Zn, F7-100% RDF + FYM 5 t/ha, F8-100% RDF + FYM 5 t/ha + Zn, F9-100% RDF + FYM 5 t/ha + BF and F10-100% RDF FYM 5 t/ha+BF+ Zn in this way there were 30 treatment combinations. The values of growth contributing characters viz. plant height (cm), number of tillers m -2 , dry matter accumulation (g m -2 ), and yield attributes like number of panicles m -2 , length of panicle (cm), number of panicle -1 , grain weight panicle -1 , test weight (g), grain and straw yield (q ha -1 ) of rice were increasing significantly with conventional puddled transplanted method (P1) followed by wide raised beds transplanted method (P2) and significantly superior over rest of the treatments. In case of integrated nutrient management the growth characters like plant height (cm), number of tillers m -2 , dry matter accumulation (g), yield attributes" number of panicle m -2, length of panicle, grain weight panicle -1 , test weight (g), grain and straw yield (q ha -1 ) of rice were maximum under F10 (100% RDF+5t/ha FYM + BF + Zn) which was at par with F9 (100% RDF +5t/ha FYM +BF) during course of investigation. The maximum gross return and net return were noted under P2 (wide raised beds transplanted rice) with F10 (100% RDF+5t/ha FYM+ BF + Zn) [P2F10] application. The highest benefit cost ratio were recorded with WB-TPR SRI method with (100% RDF+5t/ha FYM+ BF + Zn) treatment (P2F10) followed by WB-TPR with (100% RDF+5t/ha FYM+BF) (P2F9) they proved more remunerative then other treatment combinations. CT-TPR used higher amount of water than WB-TPR, with water saving of 14.5% in WB-TPR. Significantly higher water productivity was recorded in WB-TPR as compared to CT-TPR.

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