Nutrient Uptake and Physico - Chemical Properties of Soil Influenced by Organic and Inorganic Packages in Rice.

Introduction

Basmati rice is most preferred and therefore fetch a very high premium in both international and domestic markets. From a total area of 7 lakh hectare under basmati rice in country nearly 6 lakh tonnes of milled rice is produced annually. Organic food as is self explanatory needs large quantity of organic manures to supply nutrients in soil but on the contrary, there is a serious decline in organic matter in Indian soils particularly in arid, semi-arid and sub-humid climate. Application of organic manure not only improves the soil organic carbon for sustaining the soil physical quality but also increases the soil N. The replacement of external inputs viz., chemical fertilizers by farm-derived organic inputs normally leads to a reduction in variable input costs under organic management. In Chhattisgarh, by virtue of using less quantity of chemical fertilizers and pesticides and dependency upon naturally available sources of nutrients, producing organic food could have better opportunity towards high remuneration with premium price in market with inherent lesser cost advantage (Singh et al., 2001). Therefore, an experiment has been conducted to evaluate different organic inputs, nutrients sources as well as to compare the chemical and integrated nutrient management in rice

Materials and Methods

Field experiment was carried out during Kharif season of 2010 and 2011 at the Research-cum-Instructional Farm, Indira Gandhi Krishi Vishwavidyalaya, Raipur (CG), which had adequate facilities for irrigation and drainage. During the last seven years Rice-Potato-Fallow and rice – onion – fallow cropping system was adopted with recommended package for organic and integrated nutrient management practices. Bulk density (mg^-3)1.35, Organic carbon (%) 0.64, pH 7.69, EC (dSm^-1 at 25 °C) 0.21 ,Available N, P and K (kg ha^-1) content were 226.65, 19.83 and 324.42  kg ha^-1 respectively the experiment was conducted in randomized block replicated Thrice With a Plot size of 10 x 10 m in Kharif season The seven Treatments comprise of 50% RDF+ 50% N (CDM), 100% N (1/3^rd each CDM+NC+CCR), T₂+GM in rice, T₂+ DSP, 50% N (CDM) + Azospirillum + RP + PSB, 50% N (CDM) + Azospirillum + RP + PSB and 100% RDF 80: 50: 30 N: P₂O₅:K₂O Kg/ha). The seed was sown by drilling the seeds in lines in raised nurseries. The seed rate was 40 kg ha^-1. The transplanting was done with spacing of 20 x 10 cm row to row and plant to plant distance. The recommended dose of fertilizer was 80:50:30 kg NPK ha^-1 respectively. The full dose of P and K and 30% of the N was applied at the basal dose and the remaining quantity N was given in 2 splits i.e. 40% at tillering stage and 30 % at PI stage. The P and K were applied through SSP and MOP, Rock Phosphate and biofertilizers namely PSB and Azospirillum .and other organic sources like CDM, Neem cake etc. Nitrogen was given in the form of urea, FYM, crop residues and neem cake. The CDM, crop residues, neem cake and green manure (Sesbania rostrata) and 30 % of N were applied as the basal dose. Two hand weeding was done at 30 and 50 DAT. Water management was given to the crop as per requirement. Water level of 5 ± 2 cm depth was maintained during the crop growth period. crops were harvested with the help of sickles. Soil samples for various soil physico-chemical properties i.e. pH, electrical conductivity, organic carbon, available nitrogen, available phosphorous and available potassium were analyzed  after harvest of crop. Soil pH was determined by digital automatic pH meter in soil water suspension 1:2.5 (Piper, 1967). Electrical conductivity (EC) was determined by taking supernatural liquid of soil water suspension prepared for pH determining by using conductivity meter (Black, 1965). Organic carbon was estimated by Walkley and Black rapid titration method (Piper, 1967). Bulk density was determine by removing natural undisturbed core sample from soil up to 21cm depth with 7 cm intervals by core sampler the samples where oven dried 105 ^oC to a constant weight bulk density was calculated by following formula:

Available nitrogen of the soil was determined by alkaline permanganate method of Subbiah and Asija (1956). Available phosphorous of the soil was estimated by Olsen’s method (Olsen’s et al., 1954). Available potassium was determined by flame photometer after 5 minutes shaking with 25 ml of 1 N ammonium acetate (Hanway and Heiddle, 1952). Whereas Water uptake is calculated by the following formula: (Hong and Song, 1998)

Water uptake (ml) = 100/2gm x Actual water absorbed.

Results and Discussion

N Uptake in Grain and Straw

The data regarding nitrogen uptake in grain, straw and total are presented in Table (1) Plots treated with (100% RDF) resulted significantly higher uptake of N in grain and straw which was at par with T₁ (50%RDF + 50%N applied through CDM), over rest of the treatments.  Poor most N-uptake in grain was recorded under (50%N applied through CDM + Azos + RP + PSB). As far, the total uptake of N, significantly higher total N uptake was recorded under T₇. On an average the 100% inorganic treatments showed higher N uptake in grain and straw and total followed by the INM treatment where as the treatment under 50% organic manure given the lowest N uptake in grain and straw. These results were in agreement with the findings of Hatwar et al (1992).

Table 1: Grain N uptake, Kg ha^-1, straw N uptake, Kg ha^-1, Total N uptake, Kg ha^-1, Water uptake in grain (ml) of rice as influenced by different nutrient management (pooled 2 years).

Water Uptake in Grain (ml)

Water uptake by rice have been evaluated and data are presented in table (1) Treatment T₃ (100% N applied through 1/3 each CDM + NC + CCR) + GM in rice recorded the highest water uptake followed by T₄ (100% N (1/3 each CDM + NC + CCR) whereas the treatments T₅ (50% N(CDM) + Azos + RP + PSB) gives the lowest value for water uptakes in grain.  On comparison of inorganic , organic and integrated nutrients Practices, highest water required for its uptake by rice under organically produced crop (Sarawgi et al, 2006).

 Available N, P and K Status of Soil (Kg ha^–1)

Available N, P and K status of soil after harvesting of rice are shown in Table (2) Application of 100% RDF helped to accumulate higher N, P and K in soil over rest of the treatment. In different treatments available N ranged from 221-260 kg ha^-1, available phosphorous ranged from 17.60 to 23.40 kg ha^-1 and available K ranged from 243 to 284 kg ha^-1 (Urkurkar et al, 2010).

Table 2: Available Nitrogen, phosphorus and potash in soil as influenced by different nutrient management after harvest (pooled 2 years).

Physico Chemical Properties of Soil

Bulk density was higher in 100% RDF (T₇) as compared to other treatments. Here significantly lower bulk density was recorded under T₆ (T₂ + Azos + PSB) which was at par with rest of the treatments Table (3). Whereas the value of pH ranged from 7.47 to 7.32  between different organic, inorganic and integrated nutrient management treatments however significantly higher pH value was recorded under treatment T₇ (100% RDF) and other treatments viz. T₁, T₂ recorded at par and T₄ and T₅ recorded the lowest pH value. While the reading of electrical conductivity ranged between 0.22 to 0.30 where T₇ (100% RDF) significantly resulted in higher value of EC over rest of the treatments T₂ (100% N 1/3 CDM + NC + CCR) recorded the lowest value of electrical conductivity. Lastly the organic carbon percentage which ranges from 0.50 to 0.54 where the maximum organic carbon was significantly recorded under treatment T₆ (100% N CDM + NC + CCR + Azos + PSB) which was at par with T₂, T₃, T₁, T₄ whereas the least organic carbon percentage was recorded under T₅. (50% N CDM + Azos + RP + PSB). These results was in collaboration with the findings of Bellakki and Badanur (1997).

Table 3: Soil physico chemical properties (BD, pH, EC, OC %) as influenced by different nutrient management after harvest (Pooled 2 years).

Acknowledgements

I am very thankful to all professors of Department Agronomy for their support to complete this work successfully.

Reference

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