Soil Test based Fertilizer Prescriptions under Integrated Plant Nutrient Supply for Rice-Rice Cropping Sequence in Inceptisols of Assam

Soil nitrogen (N) and phosphorus (P) supply is one of the growth limiting factors in many forest ecosystems. Seasonal patterns in soil N and P supply rate were examined during a 2-yr period (1994–1995) for forest floor (L, F and H) and upper mineral (Ae) horizons in an 80-yr-old aspen forest in Saskatchewan, Canada. Accumulation of plant nutrient ions on ion exchange resins incubated in the field can provide an estimate of nutrient supply rate in soils because ion exchange resins have the potential ability to simulate nutrient flux to plant roots. Nutrient supply rates and the effect of plant uptake on nutrient supply rate was assessed using ion exchange membranes buried inside and outside polyvinyl chloride (PVC) cylinders. The difference between ion flux to the membranes inside (root uptake excluded) versus outside the cylinders was used as an index of plant nutrient uptake. From May to October, nutrient uptake (µg 10 cm−2 2 wk−2) by plants ranged from 1.6 to 31.7 (NO3−-N), from 2.7 to 13.7 (NH4+-N) and from 2.6 to 12.7 (P), with maximum N and P uptake in summer. Nutrient uptake by plants also varied among horizons. In general, plant uptake of NO3−-N, NH4+-N and P was highest in the H horizon, followed by the F and Ae horizons, with lowest uptake apparent in the L horizon. The results are consistent with the distribution of plant fine roots: most were found in the H horizon (68%), followed by the Ae and F horizons (15%), and the L (2%) horizon. Autumn litterfall represented a nutrient return of 28–40 kg N ha–1 and 4–7 kg P ha–1 to the forest floor which coincided with an increase in ion supply rates in the forest floor. During the growing season, atmospheric inputs via bulk deposition and throughfall contributed small amounts of N (1.8 kg NH4+-N ha–1 and 0.23 kg NO3–-N ha–1) and P (1.38 kg ha−1 inorganic P) to the forest floor. Recycling of nutrients by litterfall and subsequent mineralization and re-assimilation by plant roots in the forest floor is a dynamic and important component of nutrient cycling in boreal aspen forest ecosystems. Key words: Forest floor, ion exchange membranes, nutrient supply

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Soil test based fertilizer prescriptions under integrated plant nutrient management system for carrot in an Inceptisol

ANNALS OF PLANT AND SOIL RESEARCH ◽

10.47815/apsr.2021.10079 ◽

2021 ◽

Vol 23 (3) ◽

pp. 329-333

Author(s):

Y.V. SINGH ◽

Keyword(s):

Nutrient Management ◽

Agricultural Research ◽

Soil Test ◽

Plant Nutrient ◽

Main Experiment ◽

Fertility Gradient ◽

Npk Uptake ◽

Initial Soil ◽

Basic Parameters ◽

Soil Fertilizer

A field experiment was conducted at Agricultural Research Farm, Banaras Hindu University, Varanasi in an Inceptisol during rabi 2020-21 to develop a targeted yield equation for carrot crop. After developing three levels of fertility gradient with respect to available NPK in soil, the main experiment was conducted by taking carrot as a test crop. Initial soil data, carrot yield and NPK uptake by carrot crop were used for obtaining four important basic parameters, viz., nutrients required to produce a quintal of carrot roots (NR%), contribution of nutrients from fertilizers (CF%), contribution of nutrients from soil (CS%) and contribution of nutrients from organic matter (%C-OM). It was found that 0.65, 0.11 and 0.83 kg of N, P2O5 and K2O, respectively were required for producing one quintal carrot yield. The per cent contribution of nutrients from soil, fertilizer and FYM were 45.33, 65.91 and 67.26 for N; 58.45, 67.86 and 108.12 for P2O5 and 5.54, 3.35 and 10.53 for K2O, respectively. The ready reckoner for fertilizer doses with NPK alone and integrated use of NPK and FYM was also made using developed basic parameters for varying soil test values and desired yield targets of carrot yield.

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Extrapolation of post-harvest soil test values in barnyard millet-based cropping sequence through multivariate analysis

Journal of Applied and Natural Science ◽

10.31018/jans.v13i4.3115 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1545-1551

Author(s):

R. Selvam ◽

R. Santhi ◽

S. Maragatham ◽

C.N. Chandrasekhar ◽

Patil Santosh Ganapathi

Keyword(s):

Tamil Nadu ◽

Calcareous Soils ◽

Multiple Regression Model ◽

Soil Test ◽

Available Nitrogen ◽

Barnyard Millet ◽

Post Harvest ◽

Fertilizer Recommendation ◽

Cropping Sequence ◽

Phosphorus And Potassium

The soil test value is based on the soil test-based fertilizer prescription/ recommendation equation. Each crop harvesting after the next crop is necessary to analyze the soil. Therefore, it is necessary to develop an alternative technique to predict postharvest soil tests after the harvest of every crop. For that a study was conducted in mixed black calcareous soils at Tamil Nadu agricultural University, Coimbatore to develop the post-harvest prediction equations for available nitrogen, phosphorus and potassium in barnyard millet cropping sequence based on a multiple regression model by considering post-harvest soil test value as the dependent variable and initial available nutrients, fertilizer doses and crop yield or crop nutrient uptake as an independent variables. The developed model was validated by computing R2 value, RMSE (root means square error), RE (relative error), and the ratio of performance to deviation (RPD) and the developed model was found to be valid. Using the validated model, post-harvest soil test values were predicted. A fertilizer recommendation was made for blackgram based on predicted post-harvest soil test values in the barnyard millet-blackgram cropping sequence. The predicted soil test values were compared with actual soil test values and it revealed that the developed model is fairly accurate and best-fitted with more precision. The predicted post-harvest soil test values of barnyard millet could be used in order to prescribe fertilizer for desired yield targets for subsequent crops.

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