E.A. Siddiq, K.V. Rao and A.S.R. Prasad
Directorate of Rice Research, Rajendranagar, Hyderabad, India
Since achieving self-sufficiency in rice in the early 1980s, India has successfully sustained this situation. However, given the absence of many of the favourable growth factors of the 1970s and 1980s and indicators of decreasing production growth over the last ten years (by about 60 percent), meeting the projected demand of 104 million tonnes of milled rice by the year 2010 without undue environmental and economic cost is the most challenging task. As there is minimal scope for horizontal growth, raising the current yield levels closer to the genetic ceiling and raising the ceiling itself are the only means for future growth. The sizeable gap known to exist between achievable and actual yields in nearly all the rice-growing states is a potential opportunity for raising the yield level in the long term (Table 1).
TABLE 1
Yield gap in major rice-growing states, 1990/91-1997/98
State |
Paddy yield |
Yield difference |
Gap of (1) over (2) | ||||||
State average |
Experimental trial average1 | ||||||||
South zone | |||||||||
Tamil Nadu |
4 460 |
5 286 |
826 |
15.6 | |||||
Andhra Pradesh |
3 767 |
5 882 |
2 115 |
36.0 | |||||
Karnataka |
3 456 |
5 250 |
1 794 |
34.2 | |||||
Kerala |
2 857 |
5 690 |
2 853 |
49.8 | |||||
North zone | |||||||||
Punjab |
5 042 |
6 460 |
1 418 |
22.0 | |||||
Haryana |
4 074 |
7 396 |
3 322 |
44.9 | |||||
Uttar Pradesh |
2 870 |
6 598 |
3 728 |
56.5 | |||||
East zone | |||||||||
West Bengal |
3 147 |
5 003 |
1 856 |
37.1 | |||||
Orissa |
1 993 |
5 620 |
3 627 |
64.5 | |||||
Bihar |
1 811 |
6 083 |
4 272 |
70.2 | |||||
Assam |
1 954 |
6 437 |
4 483 |
69.6 | |||||
Eastern Uttar Pradesh |
1 881 |
6 598 |
4 717 |
71.5 | |||||
Manipur |
3 233 |
7 619 |
4 386 |
57.36 | |||||
Tripura |
2 932 |
6 331 |
3 399 |
537 | |||||
West zone | |||||||||
Maharashtra |
2 380 |
4 501 |
2 121 |
47.1 | |||||
Gujarat |
2 146 |
5 557 |
3 411 |
61.4 | |||||
Madhya Pradesh |
1 581 |
4 710 |
3 129 |
66.4 | |||||
Rajasthan |
1 582 |
6 485 |
4 903 |
75.6 | |||||
Northwestern hills |
|||||||||
Jammu and Kashmire |
2 774 |
7 254 |
4 480 |
61.8 | |||||
Himachal Pradesh |
1 976 |
5 003 |
3 027 |
60.5 | |||||
All India |
2 759 |
5 781 |
3 022 |
52.3 |
1Mean yield of best entry (irrigated medium) at AICRIP test locations over a seven-year period.
More serious effort is needed to ascertain the widely apprehended deceleration of yield and factor productivity in the intensively cropped irrigated ecologies and to initiate research to identify the causal factors for correction. Long-term fertilizer trials established in the early 1970s with the primary objective of assessing the sustainability of intensively cropped systems, such as rice-wheat and rice-rice, indicated declining rice yields and factor productivity at constant input levels. Intensive studies were subsequently undertaken at macro and on-farm experimental levels by various organizations, including the Project Directorate of Cropping Systems Research of the Indian Council for Agricultural Research (ICAR); network research on rice-wheat systems sponsored by the International Rice Research Institute (IRRI) and International Maize and Wheat Center (CIMMYT); and an exclusive study on reversing the declining productivity trends in rice-rice systems by IRRI. Although the studies broadly concurred on the existence of a steady decrease in yield growth over time, no consistent trend was established. In the light of the past research findings on the productivity growth of rice in the two cropping systems, the present study was undertaken with the objective of gaining further insight into this subject.
The study was planned and carried out at macro-, micro- and experimental levels in the Indo-Gangetic plains (IGP) and peninsular India, representing, respectively, rice-wheat and rice-rice systems. In view of the magnitude of the subject and vastness of the area under the two cultivation systems, specific zones were selected on the basis of relative productivity level and cropping intensity (Tables 2 and 3): Punjab, Haryana, Uttar Pradesh and Bihar broadly covered the western, central and eastern zones of the IGP in respect of rice-wheat; three states, namely, Andhra Pradesh, Tamil Nadu and Karnataka in peninsular India, covered rice-rice. One to six districts were selected in each state (Gurdaspur, Patiala and Ludhiana in Punjab; Jind, Karnal and Kurukshetra in Haryana; Bareilly, Nainital, Shaharanpur, Gorakhpur, Faizabad and Varanasi in Uttar Pradesh; and Patna, Aurangabad, Bhozpur and Samastipur in Bihar under the rice-wheat system; and West Godavari, Nellore and Kurnool in Andhra Pradesh; Thanjavur, Tiruchinapalli, Tirunalvelli and Kanyakumari in Tamil Nadu; and Mandya in Karnataka under the rice-rice system). The data were accessed from various sources including published and unpublished reports from research centres, state Departments of Agriculture and ICAR institutes, in addition to personal surveys and correspondence. The period of study covered the 18 years 1981/82 to 1998/99 with emphasis on the 1990s.
TABLE 2
Agro-ecological features of selected states and districts under the rice-wheat cropping system in the Indo-Gangetic plains, 1997-98
State/district |
Yield |
Irrigated areas |
Cropping intensity | ||
Paddy |
Wheat |
Rice |
Wheat | ||
Punjab | |||||
Gurdaspur |
4 220 |
3 759 |
-2 |
- |
- |
Ludhiana |
5 738 |
4 199 |
- |
- |
- |
Patiala |
5 009 |
4 060 |
- |
- |
- |
State |
5 196 |
3 852 |
99.1 |
97.1 |
187.3 |
Haryana |
|||||
Karnal |
4 261 |
3 992 |
- |
- |
- |
Kurukshetra |
4 628 |
3 820 |
- |
- |
- |
Jind |
4 148 |
3 605 |
- |
- |
- |
State |
4 196 |
3 660 |
99.4 |
98.4 |
166.6 |
Uttar Pradesh | |||||
Bareilly |
3 467 |
2 740 |
- |
- |
- |
Nainital |
3 713 |
2 960 |
- |
- |
- |
Shahranpur |
3 995 |
2 848 |
- |
- |
- |
Faizabad |
3 362 |
2 530 |
- |
- |
- |
Gorakhpur |
2 850 |
2 384 |
- |
- |
- |
Varanasi |
3 907 |
2 344 |
- |
- |
- |
State |
3 222 |
2 418 |
62.3 |
92.5 |
148.2 |
Bihar | |||||
Aurangabad |
3 249 |
2 136 |
- |
- |
- |
Bhozpur |
3 589 |
2 857 |
- |
- |
- |
Patna |
2 650 |
2 373 |
- |
- |
- |
Samastipur |
1 344 |
2 020 |
- |
- |
- |
State |
2 043 |
1 999 |
40.2 |
88.4 |
136.9 |
11995-96.
2 - = not available.
TABLE 3
Agro-ecological features of selected states and districts under the rice-rice cropping system in peninsular India, 1997-98
State/district |
Yield |
Irrigation |
Cropping intensity | ||
Wet season |
Dry season | ||||
Andhra Pradesh |
|||||
West Godavari |
3 827 |
5 270 |
- |
- | |
Nellore |
3 918 |
4 484 |
- |
- | |
Kurnool |
4 023 |
4 001 |
- |
- | |
State |
3 473 |
4 107 |
94.8 |
122.6 | |
Tamil Nadu |
|||||
Thanjavur |
5 408 |
3 737 |
- |
- | |
Tiruchinapalli |
5 648 |
4 857 |
- |
- | |
Tirunalvelli |
5 601 |
5 484 |
- |
- | |
Kanyakumari |
5 451 |
5 928 |
- |
- | |
State |
5 345 |
4 463 |
92.0 |
117.3 | |
Karnataka |
|||||
Mandya |
3 828 |
4 806 |
- |
- | |
Shimoga |
- |
- |
- |
- | |
State |
3 447 |
4 128 |
66.8 |
114.8 |
1As paddy.
For the micro-level study, a new approach was chosen, with state and university seed farms and progressive farmers' fields representing different regions in each of the states. In the absence of planned long-term on-farm experimentation, seed farms and farmers' fields were considered reliable alternatives for data-sourcing. The large seed farms are used exclusively for breeder, foundation and certified seed production of notified crop varieties. Invariably, the same fields are used year after year for the seed production of specific crops. The farms systematically maintain information on the basis of year, season and plot with regard to the crop and variety raised, inputs used, yields obtained, etc. Similarly, progressive farmers also record crop production details for their fields. Care was taken to choose farms and farmers' fields that had practised over the last seven to ten years rice-wheat cultivation in the IGP and rice-rice cultivation in peninsular India (Tables 4 and 5). Proformas exclusively prepared for farms and seed farms were used for data collection.
TABLE 4
Features of seed farm and on-farm sources under the rice-wheat system in the Indo-Gangetic plains
Number |
Straw management |
Organic management |
Summer crop | |||||||
Seed farm |
On-farm |
Seed farm |
On-farm |
Seed farm |
On-farm |
Seed farm |
On-farm | |||
Punjab |
3 |
3 |
Burnt (2) |
Burnt |
Nil |
3 |
Mung (1) |
Potato | ||
Haryana |
2 |
6 |
Burnt (1) |
Burnt |
Nil |
2-3 |
Mung (1) |
Mung | ||
Uttar Pradesh |
3 |
- |
Ploughed (1) |
Removed |
Nil |
- |
- |
- | ||
Bihar |
7 |
1 |
Removed |
Removed |
- |
- |
- |
- |
TABLE 5
Features of seed farm and on-farm sources under the rice-rice system in peninsular India
Number |
Organic manuring |
Summer crop | ||||
Seed farm |
On-farm |
Seed farm |
On-farm |
Seed farm |
On-farm | |
Andhra Pradesh |
7 |
17 |
1 |
2 |
Fallow |
Pulses |
Tamil Nadu |
5 |
10 |
1-2 |
1-2 |
Pulses |
Legumes |
Karnataka |
3 |
1 |
1 |
1 |
- |
Fallow |
For the experimental-level study, data were obtained from long-term experiments for the assessment of nutrient requirements of the component crops and the system. These were used to evaluate the long-term effect on soil fertility and crop productivity, and also to investigate the growth trend of rice yield vis-à-vis system productivity and partial factor productivity under the two systems. Data from the long-term experiments in the IGP conducted at Ludhiana, Karnal and Pantnagar (the northwestern zone of the plains) and at Kanpur, Faizabad, Varanasi and Sabour (eastern zone), and for the rice-rice system, data from long-term experiments conducted by AICRIP, AICARP, AICRP-LTFE (ICAR) at Maruteru (Godavari Delta), Hyderabad and Nandyal in Andhra Pradesh and Thanjavur (Cauvery Delta) in Tamil Nadu, were used for experimental-level analysis.
Partial factor productivity specific to fertilizer nutrient (kg grain harvested/kg NPK applied) was computed using data from seed farm and on-farm sources. This contrasted with the computation done at macro level by earlier workers, which is not reliable because of the lack of precise information on fertilizer consumed by the component crops and the system and on produce obtained for each season.
The study of rice yield and system productivity (rice + wheat) growth in all states except Haryana, representing upper, central and lower zones of the IGP, revealed an increasing trend (Tables 6 and 7). The pace of growth, however, varied according to the state, regions within the state and component crops. Compared to the very low growth rate of rice (0.59 and 0.19 percent) and system productivity in the trans-Gangetic zone (Punjab and Haryana), it was moderately high (2.81 percent) and high (3.80 percent) in Uttar Pradesh and Bihar, respectively, over the 18-year period (1981/82-1998/99).
TABLE 6
Yield growth (tonnes/ha) of rice, wheat and total productivity in selected states under the rice-wheat system in the Indo-Gangetic plains, 1981/82-1998/99
Punjab |
Haryana |
Uttar Pradesh |
Bihar | ||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | ||
Crop growth rate (1981-98) |
0.59 |
1.89 |
1.14 |
0.19 |
2.74 |
1.35 |
3.80 |
2.46 |
3.15 |
2.81 |
2.40 |
2.60 | |
Crop growth rate(1981-90) |
0.72 |
2.78 |
1.58 |
0.56 |
3.67 |
1.89 |
5.82 |
1.81 |
3.93 |
5.14 |
2.00 |
3.49 | |
Crop growth rate(1990-98) |
-0.35 |
0.76 |
0.16 |
-1.70 |
0.87 |
-0.41 |
2.56 |
1.28 |
1.97 |
6.31 |
0.69 |
3.21 | |
Mean (1981-83) |
4.58 |
2.98 |
7.55 |
3.81 |
2.57 |
6.38 |
1.66 |
1.73 |
3.38 |
1.11 |
1.41 |
2.52 | |
Mean (1988-90) |
5.05 |
3.65 |
8.71 |
4.13 |
3.33 |
7.46 |
2.68 |
2.11 |
4.79 |
1.82 |
1.72 |
3.54 | |
Mean (1990-92) |
4.99 |
3.86 |
8.84 |
4.12 |
3.60 |
7.72 |
2.63 |
2.33 |
4.96 |
1.30 |
1.89 |
3.19 | |
Mean (1996-98) |
4.96 |
4.08 |
9.04 |
3.78 |
3.79 |
7.57 |
3.08 |
2.50 |
5.58 |
1.97 |
1.99 |
3.97 | |
% increase 11 |
10.5 |
22.8 |
15.3 |
8.49 |
29.57 |
16.99 |
61.73 |
22.17 |
41.55 |
64.38 |
21.91 |
40.58 | |
% increase 22 |
-0.5 |
5.8 |
2.3 |
-8.19 |
5.20 |
-1.94 |
16.89 |
7.55 |
12.51 |
51.49 |
5.70 |
24.41 | |
% increase T3 |
8.5 |
37.1 |
19.8 |
-0.7 |
47.4 |
18.7 |
85.8 |
45.2 |
65.1 |
78.6 |
41.5 |
57.8 | |
Contribution % |
66.6 |
79.9 |
49.2 |
71.9 |
96.1 |
89.0 |
89.4 |
80.3 |
1% increase 1 = percentage increase of mean (1988-90) over mean (1981-83).
2% increase 2 = percentage increase of mean (1996-98) over mean (1990-92).
3% increase T = percentage increase of mean (1996-98) over mean (1981-83).
The growth rates of rice and system productivity during the 1990s compared to those in the 1980s, however, registered a sharp decline to a very low level with signs of a negative trend in the western zone. In Uttar Pradesh, although the decline persisted through the 1990s, it was moderate, unlike in Bihar, where both rice and system productivity registered a quite high growth rate (6.31 and 3.21 percent). As for the influence of the component crops on changes in system productivity, wheat appeared to influence most in the western zone and rice in the eastern zone.
District-level findings reflected a similar trend, with all the districts in the western region showing invariably very low positive to negative growth during the 1980s and 1990s (Table 7). Significant linear growth (1981-99) was not seen in any of the three districts in Punjab and, disturbingly, Ludhiana District registered negative growth. In Haryana, Karnal District again showed growth stagnation at a very low level. The impact of low growth in Karnal District (possibly due to the very large area under low-yielding traditional basmati rice for export) is seen at state level. The growth pattern of the region, especially in Punjab State, suggests that yield levels of rice are unlikely to increase using currently available varietal technology. This conclusion reinforces the earlier findings from yield gap analysis. Serious research and development efforts should be made to develop and popularize varietal technologies of higher ceiling to present genetic yield. Although hybrid rice is one potential technological option for such areas, hybrids ideally suited to this region have not yet been developed. The negative trend observed in some of the districts, especially Ludhiana, warrants further in-depth study to identify and correct the biophysical causal factors, as there is no evidence to substantiate genetic deterioration of varieties (Table 7).
TABLE 7
Yield growth (tonnes/ha) of rice, wheat and total productivity in selected districts under the rice-wheat cropping system in the Indo-Gangetic plains, 1981/82-1998/99
Punjab | |||||||||||||||||||
Gurdaspur |
Ludiana |
Patiala | |||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||||||||
Crop growth rate (1981-98) |
0.45 |
2.75 |
1.46 |
-0.56 |
1.69 |
0.35 |
-0.16 |
1.97 |
0.77 | ||||||||||
Crop growth rate (1981-90) |
-0.46 |
2.86 |
1.00 |
-0.38 |
2.74 |
0.87 |
1.15 |
3.39 |
2.07 | ||||||||||
Crop growth rate (1990-98) |
0.83 |
2.39 |
1.56 |
-0.38 |
0.39 |
-0.03 |
-1.62 |
0.80 |
-0.48 | ||||||||||
Mean (1981-83) |
3.64 |
2.43 |
6.08 |
6.05 |
3.45 |
9.50 |
4.92 |
3.03 |
7.95 | ||||||||||
Mean (1988-90) |
3.68 |
3.11 |
6.78 |
5.56 |
4.17 |
9.74 |
5.00 |
3.87 |
8.87 | ||||||||||
Mean (1990-92) |
3.92 |
3.27 |
7.19 |
5.44 |
4.26 |
9.70 |
5.00 |
4.06 |
9.06 | ||||||||||
Mean (1996-98) |
4.18 |
3.84 |
8.02 |
5.57 |
4.44 |
10.01 |
4.59 |
4.29 |
8.88 | ||||||||||
% increase 11 |
0.9 |
27.7 |
11.7 |
-8.1 |
20.9 |
2.5 |
1.7 |
27.6 |
11.6 | ||||||||||
% increase 22 |
6.7 |
17.3 |
11.5 |
2.4 |
4.3 |
3.2 |
-8.4 |
5.8 |
-2.0 | ||||||||||
% increase T3 |
14.7 |
57.8 |
32.0 |
-8.0 |
28.7 |
5.3 |
-6.8 |
41.7 |
11.7 | ||||||||||
Haryana | |||||||||||||||||||
Jind |
Karnal |
Kurukshetra | |||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||||||||
Crop growth rate (1981-98) |
1.53 |
3.72 |
2.52 |
-0.07 |
2.60 |
1.14 |
1.32 |
2.46 |
1.82 | ||||||||||
Crop growth rate (1981-90) |
-0.36 |
5.59 |
2.27 |
-0.74 |
3.85 |
1.27 |
-0.58 |
4.48 |
1.65 | ||||||||||
Crop growth rate (1990-98) |
0.19 |
0.97 |
0.61 |
-1.24 |
-0.04 |
-0.63 |
-0.32 |
0.41 |
0.03 | ||||||||||
Mean (1981-83) |
3.33 |
2.20 |
5.53 |
4.03 |
2.67 |
6.70 |
4.04 |
2.73 |
6.78 | ||||||||||
Mean (1988-90) |
3.53 |
3.36 |
6.88 |
3.80 |
3.58 |
7.38 |
3.82 |
3.73 |
7.55 | ||||||||||
Mean (1990-92) |
4.03 |
3.48 |
7.51 |
4.08 |
3.86 |
7.94 |
4.61 |
3.81 |
8.42 | ||||||||||
Mean (1996-98) |
4.34 |
3.74 |
8.08 |
4.26 |
3.99 |
8.25 |
4.77 |
3.94 |
8.71 | ||||||||||
% increase 11 |
6.1 |
52.4 |
24.5 |
-5.7 |
34.0 |
10.1 |
-5.6 |
36.5 |
11.4 | ||||||||||
% increase 22 |
7.8 |
7.4 |
7.6 |
4.3 |
3.4 |
3.9 |
3.4 |
3.6 |
3.5 | ||||||||||
% increase T3 |
30.6 |
69.7 |
46.1 |
5.8 |
49.4 |
23.2 |
17.9 |
44.3 |
28.5 | ||||||||||
Uttar Pradesh | |||||||||||||||||||
Bareilly |
Nainital |
Saharanpur | |||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||||||||
Crop growth rate (1981-98) |
3.09 |
3.07 |
3.06 |
2.50 |
2.77 |
2.60 |
3.19 |
2.05 |
2.69 | ||||||||||
Crop growth rate (1981-90) |
6.63 |
2.42 |
4.81 |
3.87 |
2.58 |
3.44 |
4.77 |
3.80 |
4.32 | ||||||||||
Crop growth rate (1990-98) |
2.36 |
3.91 |
3.02 |
-0.18 |
2.64 |
0.86 |
1.19 |
2.39 |
1.66 | ||||||||||
Mean (1981-83) |
1.93 |
1.74 |
3.67 |
3.41 |
2.00 |
5.40 |
2.18 |
1.96 |
4.14 | ||||||||||
Mean (1988-90) |
3.23 |
2.01 |
5.24 |
4.53 |
2.48 |
7.01 |
3.26 |
2.61 |
5.87 | ||||||||||
Mean (1990-92) |
3.01 |
2.22 |
5.22 |
4.57 |
2.72 |
7.30 |
3.61 |
2.54 |
6.14 | ||||||||||
Mean (1996-98) |
3.54 |
2.74 |
4.91 |
4.59 |
2.83 |
7.42 |
3.99 |
2.85 |
5.41 | ||||||||||
% increase 11 |
67.6 |
15.5 |
42.9 |
32.9 |
24.1 |
29.7 |
49.4 |
33.2 |
41.7 | ||||||||||
% increase 22 |
17.8 |
23.6 |
-6.0 |
0.3 |
4.0 |
1.7 |
10.5 |
12.2 |
10.9 | ||||||||||
% increase T3 |
83.7 |
56.3 |
33.9 |
34.7 |
41.8 |
37.3 |
82.8 |
44.0 |
64.4 | ||||||||||
Uttar Pradesh | |||||||||||||||||||
Gorakpur |
Faizabad |
Varanasi | |||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||||||||
Crop growth rate (1981-98) |
5.01 |
2.60 |
3.86 |
3.98 |
1.75 |
2.96 |
5.47 |
4.31 |
4.99 | ||||||||||
Crop growth rate (1981-90) |
8.33 |
2.79 |
5.72 |
4.53 |
1.47 |
3.14 |
5.38 |
4.56 |
5.06 | ||||||||||
Crop growth rate (1990-98) |
1.96 |
5.79 |
3.59 |
1.23 |
3.58 |
2.21 |
4.79 |
2.93 |
4.04 | ||||||||||
Mean (1981-83) |
1.59 |
1.66 |
3.25 |
2.01 |
1.86 |
3.87 |
1.96 |
1.51 |
3.46 | ||||||||||
Mean (1988-90) |
2.69 |
2.11 |
4.80 |
2.89 |
2.19 |
5.08 |
2.95 |
2.19 |
5.14 | ||||||||||
Mean (1990-92) |
2.78 |
2.03 |
4.80 |
3.05 |
2.22 |
5.27 |
3.19 |
2.30 |
5.49 | ||||||||||
Mean (1996-98) |
2.94 |
2.32 |
5.27 |
3.21 |
2.44 |
5.65 |
3.66 |
2.45 |
6.11 | ||||||||||
% increase 11 |
69.1 |
27.4 |
47.8 |
43.7 |
17.7 |
31.2 |
50.8 |
45.1 |
48.4 | ||||||||||
% increase 22 |
6.1 |
14.8 |
9.7 |
5.3 |
9.7 |
7.1 |
14.5 |
6.6 |
11.2 | ||||||||||
% increase T3 |
84.9 |
40.3 |
62.1 |
60.0 |
30.7 |
45.9 |
87.0 |
62.5 |
76.3 | ||||||||||
Bihar | |||||||||||||||||||
Patna |
Aurangabad | ||||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | ||||||||||||||
Crop growth rate (1981-98) |
1.90 |
2.98 |
2.51 |
4.31 |
6.15 |
5.12 | |||||||||||||
Crop growth rate (1981-90) |
5.44 |
4.19 |
4.91 |
5.15 |
4.48 |
4.86 | |||||||||||||
Crop growth rate (1990-98) |
5.44 |
3.39 |
4.38 |
12.87 |
9.48 |
11.15 | |||||||||||||
Mean (1981-83) |
1.75 |
1.57 |
3.32 |
1.95 |
1.39 |
3.34 | |||||||||||||
Mean (1988-90) |
2.80 |
2.15 |
4.95 |
2.25 |
1.56 |
3.80 | |||||||||||||
Mean (1990-92) |
2.13 |
2.10 |
4.23 |
1.99 |
1.64 |
3.63 | |||||||||||||
Mean (1996-98) |
2.65 |
2.38 |
5.04 |
3.09 |
2.20 |
5.29 | |||||||||||||
% increase 11 |
59.5 |
36.8 |
48.7 |
15.5 |
11.7 |
13.9 | |||||||||||||
% increase 22 |
24.9 |
13.5 |
19.2 |
55.2 |
34.4 |
45.8 | |||||||||||||
% increase T3 |
51.3 |
51.7 |
51.5 |
58.9 |
57.9 |
58.5 | |||||||||||||
Bihar | |||||||||||||||||||
Bhojpur |
Samastipur | ||||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | ||||||||||||||
Crop growth rate (1981-98) |
2.92 |
5.61 |
4.07 |
2.31 |
1.57 |
1.84 | |||||||||||||
Crop growth rate (1981-90) |
2.68 |
0.02 |
1.62 |
8.42 |
3.87 |
5.74 | |||||||||||||
Crop growth rate (1990-98) |
14.72 |
9.54 |
12.27 |
-4.16 |
3.37 |
0.06 | |||||||||||||
Mean (1981-83) |
2.48 |
1.68 |
4.16 |
0.94 |
1.56 |
2.50 | |||||||||||||
Mean (1988-90) |
2.67 |
1.66 |
4.33 |
1.71 |
2.12 |
3.83 | |||||||||||||
Mean (1990-92) |
2.15 |
2.04 |
4.19 |
1.50 |
1.76 |
3.26 | |||||||||||||
Mean (1996-98) |
3.46 |
2.73 |
6.19 |
1.35 |
2.04 |
3.39 | |||||||||||||
% increase 11 |
7.6 |
-1.2 |
4.1 |
81.7 |
35.9 |
53.2 | |||||||||||||
% increase 22 |
60.9 |
33.8 |
47.7 |
-9.9 |
15.7 |
3.9 | |||||||||||||
% increase T3 |
39.6 |
62.2 |
48.7 |
43.8 |
30.4 |
35.4 |
1% increase 1 = percentage increase of mean (1988-90) over mean (1981-83).
2% increase 2 = percentage increase of mean (1996-98) over mean (1990-92).
3% increase T = percentage increase of mean (1996-98) over mean (1981-83).
In Uttar Pradesh, the rice growth rate was moderate over the 18-year period, but decreased rapidly during the 1990s in all districts except Varanasi, in contrast to wheat, which registered increased growth (Table 8). The overall moderate growth of rice at state level in the 1990s should not mislead the state into remaining complacent, as it is expected that the growth rate in many of the major rice-growing districts, especially in the western region, will be alarmingly low. All districts, except Samastipur in Bihar, have shown impressively high growth (5.44-14.72 percent), which is either higher than, or comparable to, that of the 1980s (Table 7). There are three major reasons for this impressive growth:
If this growth pattern is maintained, Bihar could soon be a major contributor to sustained yield growth at national level.
Overall analysis of growth trends across states and districts in the IGP suggests, with certain exceptions, a negative association between growth rate and yield level. The majority of the high productivity districts show relatively low growth rates (as in the trans-Gangetic zone) and low productivity districts register high growth rates (as in the central and eastern zones).
The study of system productivity revealed an upward trend (as observed in rice and wheat), with the pace varying according to the region. In the high-productivity upper Gangetic zone, the growth rate was quite low (<1.5 percent) in all districts except Jind, while it was fairly high (2.60-3.86 percent) in the medium-productivity zone (central part of Uttar Pradesh) and impressively high with a few exceptions in the low-productivity zone (eastern Uttar Pradesh and Bihar) (Table 7). The relative influence of rice or wheat or both on the growth rates achieved varied, depending on the region. In the upper Gangetic zone and the lower Gangetic plains (Bihar), rice and wheat had an equal influence; in eastern Uttar Pradesh rice was the major influence.
In the high-productivity areas with very low growth rates, the optimization and sustenance of yield by diagnosing and correcting yield-limiting factors should receive priority attention. If the constraint is found to be a genetic limitation of the currently cultivated varieties, then a variety with a higher yield threshold should be developed. The readily available hybrid technology and new plant varieties already being developed might help to raise the ceiling. Researchers and policy-makers are further concerned about the signs of declining yield in a few districts (for example Ludhiana) under the rice-wheat system. This should be viewed as an early warning of the need for serious research in high productivity areas.
Data-sourcing for micro-level study from seed farms and progressive farmers has been a difficult experience. The use of data from large seed farms with highly reliable information on output/input was found to be a good alternative to structured experiments, which would take several years to generate such data. Analysis of the yield growth of rice and system productivity confined to the last seven to nine years revealed the trends to vary, depending on the region and the farm. The trend of very low positive to negative growth observed at most of the seed farms in the trans-Gangetic zone concurred with that observed at macro level (Tables 8 and 9). In the farmers' fields, the level of growth was relatively higher than in the seed farms. Unlike the component crop, wheat, which showed higher growth (5.4-10.8 percent), growth in rice was highly negative, especially in those with high yield average. Moderate-to-high growth observed in certain seed farms and farmers' fields could be taken as an indication that even within a district or subdistrict there could be pockets with scope for a sizeable yield increase. Farm-to-farm differences in the level of crop management by individual farmers could be the reason for instances of high growth. Excessive application of fertilizer (a common practice among farmers in this region) may have resulted in such economically non-sustainable growth.
The findings in Uttar Pradesh suggest that yield growth follows different trends. While in Tarai region (Pantnagar) rice showed positive growth compared to wheat (which registered negative growth), at Kanpur both the crops registered high positive yield growth, with rice contributing substantially to the system productivity, and at Varanasi farm both registered negative growth (Table 10). In Bihar, unlike the high positive growth of rice yields observed in the macro-level study, data from well-managed seed farms reveal a uniformly negative trend. This situation may be explained by the very high yield level (5-6 tonnes/ha) already achieved in these farms. The inference is that until state and district yield averages attain levels closer to those of the seed farms, immense scope remains for an appreciable rise in the productivity of rice at state level (Table 11).
TABLE 8
Yield growth (kg/ha) of rice, wheat and total productivity in selected seed farms and on-farm trials under the rice-wheat system in Punjab
Seed farms | |||||||||||||
PAU, Fathegarh Sahib |
PAU, Ropar |
KVK, Patiala | |||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||
Crop growth rate |
1.91 |
0.54 |
1.29 |
-10.70 |
1.81 |
-4.75 |
-0.16 |
3.72 |
1.26 | ||||
Mean (91-93) |
4 442 |
3 822 |
8 166 |
3 288 |
2 299 |
5 542 |
5 246 |
3 550 |
8 796 | ||||
Mean (96-98) |
4 838 |
4 241 |
8 882 |
1 841 |
2 780 |
4 241 |
5 006 |
4 510 |
9 516 | ||||
% increase1 |
8.9 |
11.0 |
8.8 |
-44.0 |
20.9 |
-23.5 |
-4.6 |
27.0 |
8.18 | ||||
On-farm trials | |||||||||||||
Dalanpur |
Birdwal |
Bakshiwala | |||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||
Crop growth rate |
7.8 |
10.8 |
9.1 |
-11.4 |
5.6 |
0.0 |
-4.4 |
5.4 |
0.0 | ||||
Mean (96-98) |
4 750 |
3 850 |
9 350 |
5 700 |
5 000 |
10 900 |
6 950 |
4 350 |
11 450 | ||||
Mean (98-00) |
5 450 |
4 750 |
10 200 |
4 850 |
5 500 |
10 350 |
6 500 |
4 750 |
11 250 | ||||
% increase2 |
14.74 |
23.38 |
9.09 |
-14.91 |
10.00 |
-5.05 |
-6.47 |
9.20 |
-1.75 |
1 Percentage increase of mean (1996-97 to 1997-98) over mean (1991-92 to 1992-93).
2Percentage increase of mean (1998-99 to 1999-2000) over mean (1996-97 to 1997-98).
TABLE 9
Yield growth (kg/ha) of rice, wheat and total productivity in selected seed farms and on-farm trials under the rice-wheat system in Haryana
On-farm trials | ||||||||||||||||||||||
Rasulpur 1, Karnal |
Kherachapra, Karnal |
Rasulpur 2, Karnal |
Rasulpur 3, Karnal | |||||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||||||||
Crop growth rate |
1.45 |
1.55 |
1.49 |
2.97 |
1.87 |
2.48 |
1.65 |
2.65 |
2.09 |
2.36 |
3.25 |
2.73 | ||||||||||
Mean (1993-95) |
6 200 |
4 650 |
10 850 |
5 900 |
5 000 |
10 900 |
6 450 |
5 000 |
11 450 |
6 350 |
4 750 |
11 100 | ||||||||||
Mean (1997-99) |
6 650 |
4 950 |
11 600 |
6 700 |
5 450 |
12 150 |
6 900 |
5 550 |
12 450 |
6 900 |
5 450 |
12 350 | ||||||||||
% increase1 |
7.26 |
6.45 |
6.91 |
13.56 |
9.00 |
11.47 |
6.98 |
11.00 |
8.73 |
8.66 |
14.74 |
11.26 | ||||||||||
On-farm trials |
Seed farm | |||||||||||||||||||||
Rasulpur 4, Karnal |
Sikanderpur, Sirsa |
DWR, Karnal | ||||||||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | ||||||||||||||
Crop growth rate |
-4.44 |
1.02 |
-1.90 |
-2.94 |
2.47 |
-0.36 |
7.22 |
2.84 |
4.91 | |||||||||||||
Mean (1993-95) |
6 350 |
5 125 |
11 475 |
5 500 |
3 750 |
9 250 |
4 600 |
4 450 |
9 050 | |||||||||||||
Mean (1997-99) |
5 300 |
5 300 |
10 600 |
4 750 |
4 750 |
9 500 |
5 349 |
4 978 |
10 327 | |||||||||||||
% increase1 |
-16.54 |
-7.63 |
-13.64 |
-13.64 |
2.70 |
16.27 |
11.87 |
14.10 |
1Percentage increase of mean (1997-98 to 1998-99) over mean (1993-94 to 1994-95).
TABLE 10
Yield growth (q/ha)1 of rice, wheat and total productivity in selected seed farms under the rice-wheat system in Uttar Pradesh
GBPUA, Pantnagar |
Kanpur Nagar |
Varanasi, UP | ||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | ||
Crop growth rate |
0.80 |
-0.55 |
-0.11 |
13.80 |
1.59 |
7.44 |
-3.34 |
-3.11 |
-3.13 | |
Mean (1991-93) |
45.00 |
25.83 |
70.83 |
28.89 |
38.84 |
67.72 |
43.68 |
42.50 |
86.18 | |
Mean (1998-2000) |
44.54 |
28.42 |
72.96 |
53.13 |
43.65 |
96.78 |
35.33 |
34.38 |
69.70 | |
% increase2 |
-1.03 |
10.05 |
3.01 |
83.92 |
12.40 |
42.90 |
-19.12 |
-19.12 |
-19.12 |
1 1 q = 100 kg.
2Percentage increase of mean (1998-99 to 1999-2000) over mean (1991-92 to 1992-93).
TABLE 11
Yield growth (kg/ha) of rice, wheat and total productivity in seed and on-farm trials under the rice-wheat system in Bihar
Seed farms | ||||||||||||||||
Lodipur, Jahanabad |
Kurtha, Patna |
Samhuta, Rohtas |
Piro, Bhojpur | |||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | |||||
Crop growth rate |
-0.46 |
-6.31 |
-2.68 |
-1.26 |
-12.86 |
-4.77 |
-0.23 |
-12.15 |
-5.28 |
-7.34 |
-2.08 |
-5.38 | ||||
Mean (1992-94) |
5 174 |
3 025 |
8 199 |
6 218 |
4 830 |
10 145 |
4 909 |
4 222 |
9 130 |
5 287 |
2 800 |
8 087 | ||||
Mean (1997-99) |
4 855 |
2 136 |
6 991 |
5 280 |
2 032 |
7 311 |
4 399 |
2 244 |
6 643 |
3 273 |
2 348 |
5 620 | ||||
% increase1 |
-6.16 |
-29.40 |
-14.73 |
-15.09 |
-57.94 |
-27.93 |
-10.39 |
-46.84 |
-27.25 |
-38.10 |
-16.16 |
-30.50 |
Seed farms |
On-farm trials | ||||||||||||||||
Daudnagar, Aurangabad |
Naubatnagar, Patna |
Sabajpura, Patna |
Piro, Bhojpur | ||||||||||||||
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total |
Paddy |
Wheat |
Total | ||||||
Crop growth rate |
-1.23 |
-19.21 |
-14.80 |
1.38 |
-11.00 |
-3.49 |
-4.48 |
-17.19 |
-12.93 |
8.75 |
4.99 |
7.41 | |||||
Mean (1992-94) |
5 845 |
4 700 |
10 545 |
4 748 |
4 148 |
8 896 |
5 858 |
4 874 |
10 732 |
3 400 |
1 963 |
5 425 | |||||
Mean (1997-99) |
4 724 |
2 254 |
4 616 |
4 857 |
2 500 |
7 356 |
4 268 |
2 002 |
5 269 |
4 960 |
2 400 |
7 360 | |||||
% increase1 |
-19.18 |
-52.04 |
-56.23 |
2.29 |
-39.73 |
-17.31 |
-27.14 |
-58.92 |
-50.90 |
45.88 |
22.29 |
35.67 |
1Percentage increase of mean (1997-98 to 1998-1999) over mean (1992-93 to 1993-94).
Reports of nutrient imbalances and depletion due to the heavy withdrawal of crops - more so in intensively cultivated high-productivity regions - have been instrumental in experiments focusing on systematic and continuous monitoring of growth trends; strengthening of long-term nutrient dynamics in the soil-plant system; and sustainability of the two rice-based cropping systems. In the present study, data already being generated by such long-term experiments by various national and international organizations have been compared with the observations of the macro- and micro-level studies. Data from long-term experiments at Ludhiana, Karnal and Pantnagar, repre-senting the high-productivity northwestern region, indicated a significant decline in the growth trends of rice at recommended levels of fertilizer application. This finding confirmed the trend observed by the macro- and micro-level studies. In contrast, the growth trends of wheat were found to fluctuate (Table 12). The decline of rice yields in the Tarai Region has been attributed to zinc deficiency and a loss of native soil fertility in terms of organic carbon content and available NPK (Nambiar, 1995). A similar decline observed at the Ludhiana centre has been associated with a decreasing nitrogen supply capacity of the soil and a depletion of sulphur (Yadav, Dwivedi and Pandey, 2000).
TABLE 12
Trends in grain yields of rice and wheat in long-term experiments at recommended fertilizer application in the northwestern Gangetic plains
Ludhiana |
Karnal |
Pantnagar |
Pantnagar | |||||
Initial |
Final |
Initial |
Final |
Initial |
Final |
Initial |
Final | |
Rice yield (tonnes/ha) |
6.32 |
5.47 |
6.69 |
6.10 |
7.17 |
5.50 |
4.15 |
4.25 |
Wheat yield (tonnes/ha) |
4.32 |
4.25 |
4.45 |
4.73 |
3.68 |
3.05 |
3.00 |
3.90 |
% change (rice) |
-13.4 |
-8.8 |
-23.3 |
+2.4 |
||||
Slope (rice) |
0.212 tonnes/ha |
- |
-2.33% |
+0.76% |
||||
% change (wheat) |
-1.6 |
+6.3 |
-17.1 |
+30.0 |
||||
Slope (wheat) |
-0.017 tonnes/ha |
- |
-1.95% |
+2.4% |
In the mid and lower Gangetic plains covering central and eastern Uttar Pradesh and Bihar, rice yields were again found to be declining along with wheat yields, but at a relatively slower pace, while in the lower Gangetic plains they were declining at a much higher rate (Table 13). For rice, these findings again broadly concur with the observations of the macro- and micro-level studies (except at Kanpur) in the 1990s; in the case of wheat the findings differ. In the majority of locations, the decline in the productivity of rice was found to be associated with negative balances for potassium and location-specific loss of organic carbon and available NPK (Table 14).
Reviewing the results of 18 long-term experiments conducted across the IGP, Duxbury et al. (2000) summarized that rice productivity declined by 0.05 to 0.5 tonnes/ha/year in the majority of the experiments, while wheat yields either remained static or increased with time and the productivity trend of the system was dominated by the rice yield trend. Although organic manuring is said to improve the yield potential and slow down the pace of decline in rice productivity, there is very little evidence to this effect.
TABLE 13
Yield trends (kg/ha) of rice and wheat in long-term experiments under the rice-wheat system in the central and eastern Indo-Gangetic plains
(1984-1997) |
(1984-1997) |
(1985-1997) |
(1977-1993) |
(1986-1997) |
(1973-1997) | |||||||
Initial |
Final |
Initial |
Final |
Initial |
Final |
Initial |
Final |
Initial |
Final |
Initial |
Final | |
Rice |
3 970 |
5 799 |
3 938 |
4 473 |
3 793 |
4 557 |
4 300 |
1 740 |
3 706 |
3 023 |
5 175 |
3 746 |
Wheat |
4 685 |
4 539 |
3 965 |
4 082 |
3 738 |
3 975 |
2 980 |
1 740 |
2 748 |
2 768 |
2 675 |
2 340 |
% change (rice) |
+46.1 |
+13.6 |
+20.1 |
-59.5 |
-18.4 |
-27.6 | ||||||
Slope (rice) (kg/year) |
+153 |
+44 |
+109 |
- |
-111 |
-79 | ||||||
% change (wheat) |
-3.1 |
+3.0 |
+6.3 |
-41.6 |
-0.7 |
-12.5 | ||||||
Slope (wheat) (kg/year) |
-4 |
+87 |
+5.4 |
- |
-7 |
-6.7 |
TABLE 14
Changes (%) in soil fertility characteristics under the rice-wheat system in the northeastern Gangetic plains
Location |
OC |
N |
P2O5 |
K2O |
Kanpur |
+44 |
- |
+79 |
-16 |
Faizabad |
+19 |
+13 |
+51 |
-20 |
Sabour |
-49 |
-13 |
-23 |
-28 |
Kalyani |
-35 |
+47 |
-7 |
+72 |
Barackpore |
-27 |
- |
+86 |
+34 |