Balanced fertilization through phosphorus promotion at the farm level in Pakistan.

IMPHOS started its activities in Pakistan back in 1987 on balanced fertilization through phosphate promotion at farm level.

The National Fertilizer Development Centre implemented from Rabi 1996-97 to Rabi 1999-2000 a project on "Phosphate Use Development in Pakistan" in collaboration with provincial soil fertility/plant nutrition organizations and with the financial and technical support of World Phosphate Institute (IMPHOS) through FAO. The objectives of the project were to measure the quantitative increase in yields and assess its economics in a demonstration of the effect of balanced use of fertilizers and the adequate use of phosphate to the extension workers and farming community. In the project period, 385 demonstrations were laid out on farmer's fields and spread over the entire country, on wheat, cotton, rice, maize, sugarcane and onion crops. Eight trials were conducted on permanent sites in a wheat-rice cropping system to observe the impact of balanced use of fertilizers on maintenance / built up of soil fertility status and on the yield of wheat and rice.

Fertilizer consumption in Pakistan has reached a level of 2.8 million tonnes by year 1999-2000, (figure 1) while fertilizer use in that year attained about 120 kg/ha (figure 2). However, use pattern at farm level remains highly skewed in favour of nitrogen (N) with share of 78.3 per cent compared to 21.0 per cent for phosphate (P) and negligible use of potash (K). The imbalanced use of nitrogen and phosphate is seriously impacting crop productivity, as most soils of Pakistan are deficient in N and P. One of the major reasons for low phosphate use is lack of promotional activities in a fertilizer market that is urea dominated.

On Wheat crop, 234 demonstrations were conducted under irrigated as well as rainfed conditions. With the application of nitrogen only, wheat yield increased by 80-100 per cent in Sindh and Punjab, whereas, in NWFP and Balochistan, the increase was in the range of 42-45 per cent. When P was applied in combination with N in a balanced ratio, the yield increase over control was in the range of 162-203 per cent in Punjab and Sindh. It showed an increase of 60 to 100 per cent due to P over N alone in the latter two provinces. In Balochistan the increase in wheat yield due to N+P combination was in the range of 100-105 per cent. The increase due to potassium over N and P was in the range of 15-20 percent in in Punjab and Sindh, whereas in the other two provinces (NWFP and Balochistan) the increase was relatively lower. At balanced use of nutrients, the value cost ratio (VCR) was 3.5 to 4.0 in Punjab and Sindh, and ranged from 2.0 to 3.0 in Balochistan and NWFP indicating that balanced and optimal use of nutrients is highly remunerative (Table 1). The grain nutrient ratio (GNR) ranged from 7-13 kg of grain per kg of applied nutrients (NPK).

Fifty demonstrations were laid out on cotton crop in Punjab and Sindh. The results were erratic due to vulnerability of crop to pest attack. However, in general fertilizer application proved to be more rewarding in Sindh than in Punjab. In Punjab, NP increased the yield by 68 per cent, whereas in Sindh the same treatment increased the yield by 227 per cent. The Value cost ratio was in the range of 3.7 to 5.0 in Punjab, whereas in Sindh it ranged from 7.9 to 13.2.

For rice crop, 64 demonstrations were conducted in the province of Punjab, Sindh and NWFP. For Basmati, the paddy yield increased in the range of 42-62 per cent with the use of N, but NP combination increased the yield in the range from 87 to 121 per cent. This means significant increase in yield of 40 to 60 per cent by application of P over N alone; NP combination resulted into highest value cost and grain nutrition ratio (GNR). The response of coarse rice variety (IRRI) to fertilizer application was more pronounced in Sindh than in Punjab. Nitrogen application increased the paddy yield by 50 and 90 per cent in Punjab and Sindh respectively. The average increase with the use of NP was 80 and 165 per cent in Punjab and Sindh, showing significant (P) contribution to yield of 30-70 per cent. Potassium application increased the yield in the range of 10-15 per cent only.

Eighteen demonstrations were laid out on maize crop in NWFP and Punjab, the average increase in yield was 70 per cent with the use of N, which increased to 179 per cent with NP combination. In NWFP, NP combination increased the yield by 96 per cent. The VCR for this crop was from 4.1 to 4.9 in Punjab (table 2) and less than 3.0 in NWFP.

Nine trials were conducted on sugarcane crop in Sindh and NWFP. The combination of N and P increased the can yield by 265 per cent in Sindh whereas; the increase with this treatments was 68 per cent in NWFP. NP combination resulted into highest VCR and cane to nutrient ratio in both of these provinces.

In Balochistan, 10 demonstrations were conducted on onion crop. N fertilizer increased onion yield by 43 per cent. By combining P with N yield was further increased to 100 per cent and the combination of all the three NPK nutrients resulted into 142 per cent increase in yield. The value cost ratio for NP and NPK combination was 17.

Eight demonstrations were conducted on permanent sites in rice-wheat cropping system. With the application of phosphorus, crop P content increased over time in most of the sites. In case of K a general downward trend was observed. Organic matter remained almost constant with slight improvement in some cases. The fertilizers improved both crops' yields, which were in general slightly higher during last cropping seasons. The N and P combination proved best in economical terms.

During 1997-98, a special promotional campaign was launched in collaboration with Agriculture extension directorate and 382 demonstrations were laid out on farmer's fields. The recommended fertilizer dose increased the yield in the range of 8.64 to 48.91 per cent with the average increase of 21.49 per cent on Punjab basis. The special programme on wheat was again launched in 1999-2000, in the Punjab, a province that contributes 70 per cent to total wheat output in the country. One hundred thirty three demonstrations of one acre each were laid out at farmer's fields with the simple treatment of (i) control (ii) NP (iii) NPK. The results showed an increase in yield from 68 to about 111 per cent over control due to balanced application. There was a record wheat production in the province, 16.3 million tonnes in 1999-2000 compared to 13.2 million tonnes achieved in the previous year. This was mostly due to increase in phosphate use as its consumption on wheat crop in 1999-2000 increased to 271 thousand tonnes compared to 211000 tonnes in 1998-99, an increase by 28 per cent.

Farmer's field days under the motto "seeing is believing" were organised in all the provinces to show to the farmers the impact of fertilizer at the demonstrations sites. Two symposiums were organised during 1997 and 1999, which attracted participants of high-level, including the planners, researchers, extensionists and experts of fertilizer industry. The brochure "Grow more wheat through balanced fertilization" was published and widely distributed among the extension staff and farmers. A pocket guide for extension workers on "Fertilizer Recommendations in Pakistan" was prepared and distributed among field workers.

The results of this project show that an intensive promotional activity on "Efficient and Balanced use of Fertilizers" should be launched at national level to promote balanced and integrated use of nutrients to educate farmers and to increase productivity per unit of nutrients, conserve the environment and improve economic return to farmers.

Table 1: Agro-economic analysis of impact of fertilizers on wheat yield in irrigated area of Punjab
1996-97 to 1999 - 2000 (Average of 93 demonstrations)

N @ Rs. 15, P205 @Rs.23, K2O @Rs.22/kg and wheat Rs.6/kg

Table 2: Agro-economic analysis of impact of fertilizers on maize yield in Punjab during 1997 to 1999
(Average of 5 demonstrations)