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Blanket recommendation |
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Fertilizer recommendation for cassava in India started with the establishment
and research work initiated in 1960s at Central Tuber Crops Research Institute
(CTCRI), Thiruvananthapuram, Kerala, India. From earlier studies on different
cassava clones grown with different levels of organic manures and inorganic
fertilizers, it was recommended to apply 12.5 t/ha of farm yard manure (FYM) and
100:100:100 kg/ha N, P2O5 and K2O (Mandal et al., 1973). A similar
recommendation was also made by Pillai et al. (1985). But, later studies by
Kabeerathumma and Ravindran (1996) showed that the rate of P application can be
reduced to 50%, thus changing the NPK recommendation to 100:50:100 kg/ha. Based
on these and other related studies, Nair et al. (2004) now recommend to apply
100:50:100 kg/ha N, P2O5 and K2O for high-yielding cassava varieties and
50:25:50 kg/ha for M-4 and local cultivars. Half the dose of N and K, and the
entire amount of P need to be broadcast at the time of final land preparation
and the remaining quantities of N and K are to be applied in short bands around
each plant 45-60 days after planting. The classical concept of blanket
fertilizer recommendation with fixed rates and timings has been developed based
on differential rate fertilizer trials conducted in CTCRI farm or a few other
farms. Later studies in many crops indicated the that this kind of fertilizer
recommendation cannot be extrapolated to areas other than the sites where the
experiments are conducted because of the high temporal and spatial variability
of soil and plant properties in farmers’ fields. |
Blanket recommendation of N, P2O5 and K2O for cassava in India. |
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STCR Concept |
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Swadija and Sreedharan (1998) developed fertilizer rates for targeted yields of
cassava based on soil test crop response (STCR) concept in laterite soils of
Kerala and Selvakumari et al. (2001) developed the same concept for soils of
Tamil Nadu. In STCR concept, fertilizer rates are calculated for a targeted
yield based on soil test data and based on a single yield uptake relation
function. This is not so in real situation. More importantly, it does not take
into account the interactions among the nutrients. Each nutrient requirement is
calculated individually, irrespective of the levels of other nutrients in soils.
Both the above concepts do not consider nutrient interactions as the main
influencing factor for plant nutrient uptake and the internal nutrient
efficiency at higher yield levels. |
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References: |
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Mandal, R.C., K.D. Singh and S.B.
Maini. 1973. Effect of plant density, fertility level and shoot number
on tuber yield and quality of tapioca. Indian Journal of Agronomy 18: 498-503. |
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Pillai, N.G., B. Mohankumar, P.G. Nair, S. Kabeerathumma
and C.R. Mohankumar. 1985. Effect of
continuous application of manures and fertilizers on the yield and quality of
cassava in laterite soil. In: T. Ramanujam, P.G. Rajendran, M. Thankappan, C.
Balagopalan and R.B. Nair (Eds.). Proc. Tropical Tuber Crops Nat. Symp., CTCRI,
Thiruvananthapuram, India. Nov 27-29, 1985. pp. 109-113 |
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Kabeerathumma, S. and C.S. Ravindran.
1996. Long-term effects of manures and fertilizers in acid Ultisol growing
cassava. Annual Report, CTCRI, Kerala, India. pp. 16-17. |
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Nair, G.M., S. Ramanathan and T.
Asokan Nambiar. 2004. Agrotechniques of tuber crops. CTCRI, Kerala,
India. 32 p. |
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Selvakumari, G., R. Santhi and R.
Natesan. 2001. Fertilizer recommendations based on STCR technology for
the state of Tamil Nadu. In: P. Subba Rao and S. Srivasthava (Eds.). Soil Test
Based Fertilizer Recommendations for Targeted Yields of Crops. All India
Coordinated Research Project for Investigations on Soil Test Crop Correlation.
Indian Institute of Soil Science, Bhopal, Madhya Pradesh, India. pp. 267-297. |
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Swadija, O.K. and C. Sreedharan. 1998. Fertilizer
prescription for targeted yields of cassava in laterite soil. Journal of Root
Crops 24(2): 137-142. |
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