Effect of Long Term Application of Fertilizer and Manure on Establish Relationship between Soil Organic Carbon Fractions with Yield of Maize and Wheat Crops under Maize-Wheat Sequence in Heplustepts

Sustainable agriculture involves successful management of resources for increase agricultural production to satisfy changing human needs, while maintaining or enhancing the environment and natural resources (FAO, 1989). Long-term experiments initiated during 1930's and 1940's in India revealed that for sustained crop production adequate P and K fertilization was necessary along with nitrogen (Nambiar and Abrol, 1989). Many of' these experiments were not followed for detailed monitoring of soil fertility. Phosphorus is the second major nutrient in practical agriculture, being fairly immobile, becomes unavailable for plant uptake through conversion to insoluble form. Under such circumstances, microbial biomass although relatively small, can be an important source of P for microorganisms. Measurement of P content of soil biomass is essential for an accurate assessment of its important in P cycling crop nutrition (Rao and Khera 1995). International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 9 (2017) pp. 600-606 Journal homepage: http://www.ijcmas.com


Introduction
Sustainable agriculture involves successful management of resources for increase agricultural production to satisfy changing human needs, while maintaining or enhancing the environment and natural resources (FAO, 1989). Long-term experiments initiated during 1930's and 1940's in India revealed that for sustained crop production adequate P and K fertilization was necessary along with nitrogen (Nambiar and Abrol, 1989). Many of' these experiments were not followed for detailed monitoring of soil fertility. Phosphorus is the second major nutrient in practical agriculture, being fairly immobile, becomes unavailable for plant uptake through conversion to insoluble form. Under such circumstances, microbial biomass although relatively small, can be an important source of P for microorganisms. Measurement of P content of soil biomass is essential for an accurate assessment of its important in P cycling crop nutrition (Rao and Khera 1995).
The role of microorganisms in P turnover and P availability was found to be more important in the organic system (Fliessbach et al., 1998). Microbial biomass phosphorus is a significant source of P to plants and its agricultural effectiveness could be modified by the addition of limestone. Fertilizers and organic amendments i.e., the application of N, P, K and FYM increasing of soil microbialbiomass C and dehydrogenase activity (He et al., 1998). The mineral-fertilizer recommendations are inadequate, whereas annual application of FYM along with NPK fertilizers sustains yield and soil productivity (Ranjan Bhattacharyya et al., 2008). The application of chemical fertilizer along with organic manure increased soil fertility status in terms of pH, organic carbon, available N, P, K, S and B as compared to its initial values of cropping system (Manjhi et al., 2014). The major constraint affecting the soil fertility is the adequate availability of suitable fertilizer and organic manures. It's very difficult task to predict about its fertility make-up. As the soil fertility is decreasing day by day due to low use of farmyard manure and consequently increase in use of chemical fertilizers, our aim is to study the trend of soil status of soil in long run. The organic matter is decreasing in our soil. Therefore such study will generate useful information on managing soil health.

Materials and Methods
At the inception of the experiment, the composite soil samples were drawn from 0-15 cm depth prior to treatment application in order to as certain initial fertility status and physico-chemical properties of the experimental soil. The experiment was carried out at the Instructional Farm of the Rajasthan College of Agriculture, Udaipur, in randomized block design (RBD) with four replications The treatment consisted of three sources chemical fertilizers, organic manure and bio-fertilizer (Azotobacter) and their combinations, viz., control, 100 % N, 100 % NP, 100 % NPK, 100 % NPK + Zn, 100 % NPK + S, 100 % NPK + Zn + S, 150 % NPK, 100 % NPK + Azotobacter, FYM 10 t ha -1 + 100 % NPK (-NPK of FYM), 100 % NPK + FYM 10 t ha -1 and FYM 20 t ha -1 . Statistical analysis was done as outlined by Panse and Sukhatme (1985). The data so generated during the course of present investigation were subjected to simple correlation, regression analysis (Steel and Torrie, 1980). Pooled analysis of the data for two year was carried out using standard analysis of variance suggested by Gomez and Gomez (1984).
The humic acid fraction ascribed significant p ositive relationship with only wheat grain yield (r=0.321*), In case of humic acid fraction non significant positive re lationship with maize grain yield, maize stover yield and wheat straw yield. The fulvic acid fraction ascribed all maize grain and stover yield and wheat grain and straw yield observed non-significant. The humin fraction ascribed highly significant positive relationship with maize grain yield (r=0.605**), maize stover yield (r=0.613**), wheat grain yield (r=0.632**) and wheat straw yield (r=0.600**).

Pooled stepwise regression
The regression of maize grain and stover yield, wheat grain and straw yield with its forms explains the variation in forms up to 92%, 99%, 99% and 98% respectively. soil microbial biomass carbon followed by Soil microbial biomass nitrogen, soil microbial biomass phosphorus, water soluble carbon, water soluble carbohydrates, soil dehydrogenase activity, humic acid, fulvic acid and humin to the maximum extent. The soil microbial biomass carbon fraction ascribed highly significant positive relationship with wheat grain yield, maize grain yield, soil microbial biomass nitrogen, water soluble carbon, humic acid, Humin and significant positive relationship with soil microbial biomass phosphorus and fulvic acid. The results of present investigation are in line with the finding of Thakre and Ravankar (2004) and Santhy (1999).  Humin v/s Maize grain Yield 0.605** 10 Humin v/s Maize stover Yield 0.613** 11 Humin v/s Wheat Grain Yield 0.632** 12 Huminv/s Wheat Straw Yield 0.600** * Significant, ** highly significant   The soil microbial biomass nitrogen fraction ascribed highly significant positive relationship with wheat grain yield, wheat straw yield, maize grain yield, soil microbial biomass phosphorus, dehydrogenase activity, carbon mineralization, humic acid, humin and significant positive relationship with water soluble carbohydrates and fulvic acid. These observations are in close conformity to those obtained by Vance et al., (1987).
The soil microbial biomass phosphorus fraction ascribed highly significant positive relationship with maize grain yield and significant positive relationship with wheat grain yield, dehydrogenase activity, carbon mineralization and humin.
The water soluble carbon fraction ascribed significant positive relationship with maize grain yield, maize stover yield and wheat grain yield. The water soluble carbon highly significantly correlated with dehydrogenase activity and humic acid, while it shows significant positive relationship with WSCO, carbon mineralization, fulvic acid and humin. The Water Soluble Carbohydrates fraction ascribed highly significant positive relationship with maize grain yield, wheat grain yield, wheat straw yield. The water soluble carbohydrate significantly correlated with dehydrogenase activity, carbon mineralization and humin. The dehydrogenase activity fraction ascribed significant positive relationship with maize grain yield, maize stover yield, carbon mineralization and significant positive relationship with humic acid, fulvic acid and humin (Tables 1-4).
The carbon mineralization fraction ascribed highly significant positive relationship with maize stover yield, wheat grain yield, humin and significant positive relationship with maize grain yield, wheat straw yield and humic acid. Verma and Mathur (2007) show relationship among active pools of soil organic matter and C/N, SMBC, SMBN, SMBP. The C/N ratio was highly and significantly correlated with soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), water soluble carbon (WSC), water soluble carbohydrates (WS-CHO)and dehydrogenase activity (DHA) under maize crop. The humic acid fraction ascribed highly significant positive relationship with maize grain and stover yield and wheat straw yield, fulvic acid and humin and significant positive relationship with wheat grain yield. The fulvic acid fraction maize grain and stover yield, wheat grain and straw yield observed non-significant. The fulvic acid significant correlated with humin. The humin fraction ascribed highly significant positive relationship with maize grain and stover yield, wheat grain yield and straw yield.