Effect of conservation tillage, residue and nitrogen levels on soil nitrogen fractions and their contributions in nitrogen uptake in castor (Ricinus communis)

This experiment was conducted in rainfed semi-arid tropical Alfisol at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad, India, during the period 1995 to 2014 to study the long-term effect of conservation agricultural practices on organic and inorganic N fractions in soil, their contribution to available N pool and N uptake in castor (Ricinus communis L.). The experiment was conducted in a strip split-split plot design with conventional tillage (CT) and minimum tillage (MT) as main factors, surface application of sorghum stover @ 2 tonnes/ha (SS), fresh gliricidia loppings @ 2 tonnes/ha (GL) and ‘no’ residue (NR) as sub-factors and levels of N, viz. 0 (N0), 30 (N30), 60 (N60) and 90 (N90) kg N/ha as sub-sub factors. The results of the study revealed that increasing N levels influenced exchangeable ammonical N and nitrate N. Practice of conservation tillage, application of residues and nitrogen significantly influenced the hydrolysable organic N fractions in the soil. Among these, aminoacid N, hexosamine N, hydrolyzable NH 4 + and unidentified N constituted 52%, 8%, 13% and 27% of total hydrolysable N. Linear regression relationship between castor yield and total soil N and N uptake (R2 = 0.998) was found significant. Further, inter correlations between N fractions indicated free mobility among the N fractions. Hence, the build up of N in these pools can be significantly influenced by adoption of appropriate conservation agricultural practices on long term basis in rainfed Alfisols which are highly deficient in available soil N

IMPACT OF LONG TERM TILLAGE AND RESIDUE APPLICATION ON ORGANIC CARBON POOLS AND CARBON STOCK IN SEMI ARID TROPICAL ALFISOL OF HYDERABAD

Not Availablelong term experiment was conducted in rainfed semi-arid tropical Alfisol at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad, India, during the period 1995 to 2013 to study the long-term impacts of tillage and residue application on carbon sequestration, C pools and C Management Indices and their relationship with crop yield. The experiment was conducted in a split-split plot design with conventional tillage (CT) and minimum tillage (MT) as main factors, surface application of sorghum stover @ 2t ha-1 (SS), fresh gliricidia loppings @ 2t ha-1 (GL) and ‘no’ residue (NR) as sub factors and levels of N viz., 0 (N0), 30 (N30), 60 (N60) and 90 (N90) kg N ha-1 as sub-sub factors in a castor-sorghum yearly rotation. The results of the study clearly indicated that minimum tillage significantly increased the contents of soil C pools viz., microbial biomass carbon, labile carbon and its fractions and particulate organic carbon compared to conventional tillage. It was also observed that significant inter-correlations existed among the carbon pools studied which indicated a dynamic equilibrium with each other. Of all the treatment combinations studied, the practice of minimum tillage coupled with application of Gliricidia loppings @ 2t ha-1 and nitrogen applied @ 90 kg ha-1 (MTGLN90) was found to be the most promising in terms of maintaining significantly higher carbon stock in semi arid tropical Alfisols.Not Availabl

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Not AvailableThe present study was conducted in 2009–10 with the objective to monitor the effect of restorative soil management practices on biological soil quality. The experiment was initiated in 1995 in a strip–split–split plot design with three replications. Sorghum and castor were grown in two-year rotations. The procedure comprised of two tillage treatments: conventional tillage (CT) and minimum tillage (MT; main plots), three residues treatments: sorghum stover (SS), Gliricidia loppings (GL), no residue (NR; sub-plots), and two nitrogen levels 0 (N0) and 90 kg ha–1 (N90) (sub–subplots). After 15th year of the experiment, activities of the soil enzymes, microbial biomass carbon (MBC), labile carbon (LC) and organic carbon (OC) were studied. Soil management treatments significantly influenced the soil enzyme activities. Enzyme activity was significantly correlated with MBC, LC and OC. The biological soil quality has been assessed in terms of GMeanBSQI (geometric mean of biological soil quality index). From the viewpoint of GMeanBSQI, the order of superiority of soil management treatments was: MT (0.82) > CT (0.69). The performance of the residues was in the order GL (0.87) > SS (0.75) > NR (0.65). Nitrogen @ 90 kg ha–1 (0.81) proved superior to no nitrogen (N0 – 0.70). Among all the treatment combinations, MTGLN90 was found to be the most superior management option for ensuring higher GMean in rainfed Alfisol soils. The present study indicates that crop residue management under minimum tillage is of great significance in improving the biological soil quality indicators and indices. The results obtained are significant in improving biological soil quality index and crop productivityNot Availabl

Effect of Surface Residue Management under Minimum Tillage on Crop yield and Soil Quality Indices after 6 years in Sorghum (Sorghum bicolor (L.) Moench) - Cowpea (Vigna unguiculata) System in Rainfed Alfisols

Not AvailableABSTRACT: This experiment was conducted in rainfed semi-arid tropical Alfisol at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad, India, during the period 2005 to 2010 to study the long-term effect of varying levels of surface residue application under minimum tillage on crop yields and soil quality in sorghum-cowpea system. The experiment was conducted in a randomized block design with minimum tillage (MT) as main block. The experimental treatments comprised of application of four levels of dry sorghum residues (@ 0, 2, 4 and 6 t/ha) as surface application. After 6th year of the experimentation, the pooled mean sorghum grain yield varied from 1607 to 1819 kg/ha across the treatments and was significantly influenced by the residue application. The percent increase in pooled grain yields with residue application @ 2, 4 and 6 t/ha was to the extent of 5, 9 and 13.0% respectively over the control (no residue application). Similarly, the pooled mean cowpea yield varied from 335 to 541 kg/ ha across the treatments and was significantly influenced by the residue application. The percent increase in cowpea grain yield with @ 2, 4 and 6 t/ha was to the extent of 28, 61 and 45% respectively no residue application. Significantly higher organic carbon (6.80 g/kg) content was recorded with the application of sorghum stover @ 6 t/ha which was 55.89% higher compared to control (4.36 g/ kg). The increase in available N with the application of 6t and 4t crop residue was to the extent of 19.5 and 28% respectively while significantly higher contents of soil available P (10.67 kg/ha) and K (288.8 kg/ha) were observed with application of sorghum residue @ 4 t/ha. Among the biological properties, significantly higher microbial biomass carbon (MBC) and dehydrogenase activity (DHA) were recorded with the application of sorghum stover @ 4 t/ha. Besides reducing the bulk density, the application of residues had a significant influence on the mean weight diameter (MWD) of the soil aggregates. The highest overall soil quality index (SQI: 9.58) was observed with the residue application @ 6 t/ha. A significant positive relationship was observed between SQI and pooled cowpea seed yield (R2=0.82) and pooled sorghum grain yield (R2=0.69).Not Availabl

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Not AvailableA long term study was conducted in the rainfed Inceptisol soils at All India Coordinated Research Project (AICRPDA), Rakhdhiansar (J&K) from 1998 to 2005. The main objectives of the present study were to quantify the long-term effects of conjunctive nutrient management on soil quality parameters, to identify the key indicators of soil quality using data redundancy technique and to compute integrated soil quality Index (SQI) and relative soil quality Index (RSQI) as influenced by long term INM treatments in Hill and mountainous Inceptisol soils in Northern India under maize - black gram system. Six INM treatments were considered for the study viz., T1: Control; T2: 100% N (inorganic); T3: 50% N (inorganic); T4: 25 kg N (compost); T5: 15 kg N (compost) + 10 kg N (inorganic) and T6: 15 kg N (compost) + 20 kg N (inorganic). After eight years of study, results revealed that the soil organic carbon was significantly higher with the long term application of 25 kg N (compost) (5.20 g kg-1) and 15 kg N (compost) + 20 kg N (inorganic) (5.19 g kg-1). Among the macronutrients, available N and P were significantly influenced by the integrated nutrient management treatments while available K was not influenced much. Significantly highest available N content of 156.5 kg ha-1 was observed with the application of 25 kg N through compost and significantly highest available P of 36.7 kg ha-1 was recorded with the application of 15 kg N (compost) + 20 kg N (inorganic). Among the secondary nutrients, irrespective of their significant influence, the content of both exchangeable Ca and Mg, varied from 2.47 to 3.76 cmol kg-1 and 0.43 to 0.52 cmol kg-1 respectively. Available S, being significantly influenced by the nutrient management treatments was observed to be highest under application of 25 kg N through compost (22.7 kg ha-1). Among the micronutrients, available Zn and B were conspicuously influenced by the management treatments while Fe, Cu and Mn were not influenced. Among the biological parameters viz., DHA, microbial biomass carbon (MBC) as well as labile carbon were significantly influenced by the management treatments. Application of 15 kg N (compost) + 20 kg N (inorganic) recorded significantly highest DHA (2.79 μg TPF hr-1g-1) as well as labile carbon (355.0 μg g-1 of soil) while application of 25 kg N (compost) recorded significantly highest MBC of 162.0 μg g-1 of soil. Among the physical soil quality parameters, both bulk density as well as mean weight diameter were significantly influenced by the management treatments. Soil quality assessment studies indicated that available N, exchangeable Ca, available Zn, & B, MBC and bulk density were found to be the key indicators of soil quality under maize-black gram. Among all the treatments practiced under maize-black gram system, application of 25 kg N through compost had significantly highest RSQI of 0.97 which was at par with application of 15 kg N (compost) + 20 kg N (inorganic) (0.94) ( P=0.05). The order of performance of the treatments in terms of soil quality was : 25 kg N (compost) ( 0.97) >15 kg N (compost) + 10 kg N (inorganic) (0.87) > T 100% N (inorganic) (0.83) > 50% N (inorganic) (0.81) > Control ( 0.63).Not Availabl

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Not AvailableInceptisols in the submountainous region of Indo-Gangetic Plains in India are known as low productive areas due to several constraints like decline in soil organic matter and fertility, deterioration of soil physical and biological properties. The present study was conducted with tillage as main treatments and integrated nutrient management as subtreatments to improve soil quality and to identify the key indicators of soil quality after 5 years of experimentation in maize–wheat cropping system at Ballowal Saunkhri. Conventional tillage (CT) + interculture (IC) maintained significantly higher soil quality indices (SQI) of 1.12 which was at par with 50% CT + IC + chemical weed control (CWC) (1.08). Application of nitrogen (N) through 50% (organic) + 50% (inorganic) maintained higher soil quality with SQI of 1.10 followed by application of 100% N through organics (1.08). The results indicated that reduction in the intensity of tillage to 50% with interculture practices and combined use of organic and inorganic fertilizers maintained higher soil quality in these degraded Inceptisols. The methods of principal component analysis and computation of SQI adopted will be highly useful to future researchers, land managers, and students at locations across the world having similar climatic and edaphic conditions.Not Availabl