Somaiya

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Karnataka Institute of Applied Agricultural Research

Crop : Sugarcane.

Field : Agronomy.

Collaborator : M/s. Indian Potash Ltd.

Title : To study the response of sugarcane to Potassium fertilisation on Sameerwadi soils.

Author : R .S.Sachan, A.T. Yaragattikar,P,Y,Keskar , R.G.Menon and H.L.Kulkarny.

Year : 1976-77

In an earlier experiment it was found that the application of potassic fertilizer does not produce any response in the sugarcane crop on our farm soils despite the fact that an analysis of the soil shows a deficiency of available potash. To confirm this finding an experiment was laid out as per details in Table IX.

Table IX. Experiment : Study of Response to Potassium Fertilization.

1. Field No. : D-8/72
2. Variety : Co 740
3. Replication : Four
4. Plot size : 115.2 Sq. M.
5. Date of Planting : 2nd December, 1975
6. Date of Harvest: 6th January, 1977
7. Treatments :
	Treatment	N-Kg/ha	P2 O5 Kg/ha K- Kg/ha			Mode of application
	A	250	75 250			P & K basal - N split
	B	250	75 250			P basal N + K split
	C	250	75 250			N only.
Treatment	% Germi-	Shoots/	Millable	Tonnes	Juice Quality
	nation at	ha at 120	canes/ha	yield/ha	10 Months			11 Months			12 Months			CCS/ha
	60 daya	days	at harvest	at harvest	Brix	Pol	Purity	Brix	Pol	Purity	Brix	Pol	Purity
A	64.03	203125	127608	127.6	16.32	13.42	82.2	18.07	15.66	85.3	19.63	16.15	86.8	14.42
B	65.06	202539	124391	127.7	16.80	13.99	83.35	18.98	15.98	84.2	19.06	16.63	86.2	14.34
C	64.31	208105	122051	119.70	16.44	13.53	82.2	18.53	15.31	82.65	19.22	16.05	84.3	13.16

The differences between treatments were not statistically significant either in respect of cane yield or in respect of CCS/ha. The soil of field No. D-8/72 was analysed before the experiment was laid out. The results of the analysis are given in Table X.

Table X. Experiment : Study of Response To Potassium Fertilisation - Soil Analysis Data.

E.C.	0.205 M. hos. cm
pH ( 1 2 )	7.8
Total K	1124.9 Kg/ha	Jackson 1958. Wet digestion with hydrofluoric acid and perchloric acid.
Exchangeable K
Water soluble K	10.44	Maclean, 1 : 1 soil water ratio
K fixation capacity	313.6	Verma 1972.
From this data it is seen that the soil is :
i) Low in exchangeable K
ii) High in non-exchangeable K
iii) High in water soluble K and
iv) Low to medium in K fixation capacity.
Therefore, apparently the soil is able to supply adequate potash to the crop even without potassium fertilisation. This condition may prevail for 5 to 6 more crop cycles. Thereafter, it is to be expected that increasing response to potash fertilisation will be obtainable.
III. Potash trial to test the contention that best results from application of Potash are obtained with split application (in collaboration with M/s. Indian Potash Ltd.) An experiment was conducted as per details in Table XI to test the claim that split application of Potash gives better crop response.

Table XI. Experiment : Study on Response to Split Application to Potash.

1. Field No. : D-9/72
2. Variety : Co 62175
3. Replication : Four
4. Plot size :
5. Date of Planting : 6th January, 1976
6. Date of Harvest: 17th December, 1976
7. Treatments :
	Treatment	N-Kg/ha	P2 O5 Kg/ha K- Kg/ha			Mode of application
	A	250	75 200			P & K basal - N split
	B	250	75 250			P & K basal - N split
	C	250	75 250			P basal - N & K split.
Treatment	% Germi-	Shoots/	Millable	Tonnes	Juice Quality
	nation at	ha at 90	canes/ha	yield	10 Months			11 Months			12 Months			CCS/ha
	45 daya	days	at harvest	at harvest	Brix	Pol	Purity	Brix	Pol	Purity	Brix	Pol	Purity
A	60.42	217254	98260	178.2	17.80	14.50	81.2	17.70	15.38	86.70	19.81	17.31	87.41	12.30
B	61.58	199042	112632	161.3	18.00	14.08	81.6	18.60	15.70	84.4	19.99	17.59	87.40	19.60
C	60.33	187927	106112	169.80	18.02	15.44	84.7	17.61	15.60	88.90	19.48	17.50	90.07	20.67

Differences between treatment were not statistically significant either in respect of cane yield or in respect of sugar yield.

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