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MANAGEMENT INDUCED CHANGES ON CARBON STORAGE AND SOIL FERTILITY IN RICE-LENTIL CROPPING SEQUENCE UNDER DRY LAND ECOSYSTEM

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Title MANAGEMENT INDUCED CHANGES ON CARBON STORAGE AND SOIL FERTILITY IN RICE-LENTIL CROPPING SEQUENCE UNDER DRY LAND ECOSYSTEM
 
Creator Shankar Ram
 
Contributor Prof. A. K. Ghosh
 
Subject Rice-lentil cropping sequence, dry land ecosystem, management induced changes, carbon storage and soil fertility
 
Description Ph. D. Thesis, Soil Science and Agricultural Chemistry
The present investigation was planned in the backdrop of a long term dry land field experiment (All India Coordinated Research Project on Dry land Agriculture) that was started in 2003 with three tillage and three manuring options resulting in nine treatment combinations. The three tillage treatments were (i) conventional, (ii) reduced and (iii) minimum tillage, consisting of two disc ploughing and one ploughing by cultivator representing conventional tillage; one disking and one cultivator constituting reduced tillage; one cultivator only constituting minimum tillage respectively. The three fertilization options were (i) complete inorganic fertilization (@ 80:40:30::N:P:K), (ii) 50% of N of the inorganic fertilization option substituted by farm yard manure (equivalent to 8 tonnes ha-1 FYM) and (iii) 100% of the N of the inorganic fertilization option substituted by farm yard manure (equivalent to 16 tonnes ha-1 FYM). The rice (var. NDR-97) - lentil (var. Malaviya Viswanath) cropping sequence was followed in fixed plots and the tillage options were applied before rice. A common summer ploughing (one minimum tillage) was applied to all plots after rice. Fertilizer options as indicated above were applied before rice and a uniform doze of fertilizers were applied for lentil establishment @ 20:40:20 kg N:P:K. The experiment was conducted under dry land situation and no irrigation was given. The results of the study indicate that although better rice and lentil yields were still being obtained with increasing tillage intensity, it resulted in decrease in soil organic carbon stocks. Organic carbon was physically protected inside macro aggregates and the hierarchical model of aggregate formation was validated. Intensive tillage regime resulted in breaking down of macro aggregates substantiated by higher microbial activity and carbon loss by organic matter mineralization; this led to deterioration of soil structure (MWD). Orgnic manuring resulted in improvement in soil structure which physically protected more organic matter. Hot water soluble carbohydrate was a better predictor of aggregation than hot water soluble carbon. About 2/3rd of the carbohydrate pool in aggregates were easily biodegradable. The resistant C pool increased with manuring and decreasing tillage intensity and more recalcitrant compounds were found at lower depth. The silt + clay fraction was far from saturation and the recalcitrancy index remained fairly constant in soil in the region outside the influence of organic manuring i.e. at 10-15 cm depth. Although rice yields were better with inorganic fertilization, probably because all the applied nutrients were immediately available to rice, organic manure mineralization took time, which improved physical soil structure and biological properties, improving lentil yields. It could be safely concluded that reducing tillage intensity and increasing organic manuring has strong influence on biological soil properties that reflect immediate changes in available nutrient pools and on soil structure and carbon sequestration which would have long term effects on crop production. Hence reduction of tillage and increase in manuring should be encouraged. However no generalizations can be made over cropping systems and farming situations, which need to be studied specifically to come to any recommendation.
 
Date 2017-01-19T18:18:49Z
2017-01-19T18:18:49Z
2017
 
Type Thesis
 
Identifier Ram, S. 2017. Management induced changes on carbon storage and soil fertility in rice-lentil cropping sequence under dry land ecosystem. Ph. D. Thesis, Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, BHU, Varanasi.
http://krishikosh.egranth.ac.in/handle/1/97211
 
Language en
 
Relation P0157;
 
Format application/pdf
 
Publisher Institute of Agricultural Sciences, Banaras Hindu University, Varanasi