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Zero tillage wheat and unpuddled rice: the energy, labour and cost efficient alternatives to conventional rice-wheat system

RK Sharma, RS Chhokar, RK Singh and SC Gill

Directorate of Wheat Research, Karnal, Haryana, India, Email: rks20037@gmail.com

Abstract

Farmers in the rice-wheat system of the Indo-Gangetic Plains (IGP) follow crop establishment methods such as puddled transplanted rice and conventional tilled wheat. These techniques require large amounts of energy, water and labour, which are becoming increasingly scarce and expensive. Alternative tillage options that require smaller amounts of these inputs were evaluated. Experiments were conducted at the Directorate of Wheat Research farm at Karnal, Haryana, India over many years to evaluate various tillage and crop establishment systems. The rice establishment methods tried were puddled, unpuddled (with harrow and rotary tiller) and zero tillage transplanted rice whereas in wheat the tillage options were conventional tillage, zero tillage, rotary tillage, strip tillage and bed planting. The study showed that in rice, the conventional practice of puddled transplanting could be replaced with unpuddled transplanting. In case of wheat, conventional tillage can be replaced with zero- or rotary tillage to save energy, water and labour thereby increasing profit margins for farmers.

Key Words

Zero tillage, rotary tillage, bed planting, strip tillage, rice-wheat system

Introduction

The Indo-Gangetic Plain (IGP) is of great importance to the food security of India. It extends over 1,600km with a width of 320km, including the arid and semi-arid environments in Rajasthan and Punjab and the humid and perhumid deltaic plains in West Bengal (Shankaranarayana 1982). A decline in land productivity, particularly of the rice-wheat (RW) system, has been observed over the past few years in the northern and north-western IGP despite the application of optimum levels of inputs under assured irrigation (Paroda 1997). The rice-wheat system, covering an area of around 10millionhectares (Mha), is the major cropping system in the IGP. These two crops together contribute more than 70% of total cereal production in India from an area of around 25Mha under wheat and about 40Mha under rice. The small states of Punjab and Haryana contribute 20% of the total national grain production and 50% and 85% of the government procurements of rice and wheat, respectively (Singh 2000).

The indiscriminate use, or rather misuse, of natural resources, especially water, has led to the pollution and depletion of groundwater resources (Nayar and Gill 1994). Intensive tillage and residue burning has led to depletion of soil organic C status resulting in decreased soil fertility and reduced factor productivity (Yadav 1998). It indicates that the RW system, especially residue burning, intensive tillage and injudicious use of water resources, has weakened the natural resource base. Therefore, to achieve sustainable or higher productivity, efforts must be focused on reversing the trend in natural resource degradation. Moreover, due to rising prices of inputs, it is imperative to develop technologies which save on inputs to increase the profit margins of the farmers. Hence, the study was undertaken to arrive at optimal tillage requirement in rice-wheat system to economise on energy, labour, time and ultimately the cost of cultivation.

Methods

The field studies were carried out at the research farm of the Directorate of Wheat Research, Karnal, India (2943’ N 7658’ E, 245 m above mean sea level) for 3 (2004-05 to 2006-07) wheat and 2 (2005 and 2006) rice seasons. The soil was deep alluvial sandy loam with low organic carbon content of 2.9 g kg-1 (Walkley and Black, 1934). It contained 654 g kg-1 sand (2000-20 μm), 226 g kg-1 silt (20-2 μm), and 121 g kg-1 clay (less than 2 μm) in the top 0-15 cm soil layer. The soil was non-saline (pH 8.7) having steady state infiltration rate of 3.0 mm h-1 and Olsen’s extractable P of 18.9 kg ha-1 and ammonium acetate extractable K of 157.8 kg ha-1 in the top 0-15 cm soil profile.

The experiment was conducted in split plot design with 5 tillage options in rice as main plots and five tillage options in wheat as sub-plots, replicated 3 times. The 5 tillage treatments in rice were (1) Field preparation by rotary tiller followed by ponding and transplanting (Dry rotary), (2) Field preparation with harrow followed by ponding of water and transplanting without puddling (Dry harrow), (3) Puddling with rotary tiller followed by transplanting (Wet rotary), (4) Conventional puddling followed by transplanting (Wet harrow), and (5) Transplanting under zero tillage. In wheat 5 tillage options were (1) Zero tillage (ZT), (2) Conventional, (3) Rotary tillage (RT), (4) Strip till drill and (5) FIRBS (Furrow Irrigated Raised Bed-planting System). The experiment was conducted in fixed plots imposing same treatments for each cropping phase.

For evaluating time taken to seed wheat and rice and fuel consumption under various tillage options, large scale trials were conducted at farmers’ field at 2 to 4 locations for 3 years and the data averaged.

Results

Yield of wheat and rice under various tillage options

The pooled results of three years showed that wheat yield interacted with tillage in rice and tillage in wheat (Table 1). Among tillage options in wheat, the highest yield was obtained in the rotary and zero till which was significantly better than conventional, strip and bed planting. Among tillage options in rice, puddling or dry field preparation by rotary tiller gave higher yield than other tillage options. The results showed that rotary tillage in both rice and wheat was the best option for highest yield of wheat in this rice-wheat system.

Table 1. Tillage effects on the productivity (t/ha) of wheat

Tillage in wheat

Tillage in rice

Mean

Wet Rotary

Wet Harrow

Dry Rotary

Dry Harrow

ZT

Zero Tillage

5.01

4.95

5.00

4.84

4.38

4.84

Rotary Tillage

5.16

5.00

4.87

4.78

4.59

4.88

FIRBS

4.12

4.01

4.17

4.15

4.03

4.09

Conventional

4.92

4.84

4.86

4.69

4.58

4.78

Strip till drill

4.76

4.45

4.83

4.58

4.37

4.60

Mean

4.79

4.65

4.75

4.61

4.39

 

CD (0.05)

 

Tillage in rice

Tillage in wheat

Interaction

   

0.13

0.09

0.21

In the case of rice yields also, the tillage in rice, wheat and their interaction were significant (Table 2). Among tillage options in rice, puddling or dry field preparation either with rotary tiller or with harrow were better than rice transplanted under zero tillage conditions. Puddling with rotary tiller was better than only dry field preparation either with rotary tiller or with harrow but was at par with puddling using harrow. Among tillage options in wheat, the highest mean yield of rice was recorded in conventional tillage closely followed by rotary, strip tillage and FIRBS which were at par but were better than with zero tillage of wheat followed by growing rice under different field preparation options during kharif season (monsoon)

Effect of cropping sequence on P. minor

The inclusion of short duration crop like, potato and pea, in between rice-wheat system resulted in significant reduction in population of P. minor (Fig. 1). Its population in rice-pea/potato-wheat system was 46 plants/m2 whereas in rice-wheat system was 589 plants/m2. Adoption of such a sequence will reduce the seed bank of this weed over time. Besides reducing the P. minor population this intensified system will also improve the profitability and sustainability of the system. Similarly Malik and Singh (1995) also reported the beneficial effect of crop rotation in reducing the incidence of P. minor and herbicide resistance. Crop rotation and herbicide rotation helps in lowering the selection pressure (Gressel and Segel 1990). Crop rotations do not merely delay resistance by allowing use of different management options, but they also restore diversity in weed flora. Some crop rotations [growing Egyptian clover (Trifolium alexandrinum) for two years] may even be able to exhaust the soil seed bank of P. minor, thus providing a long term solution (Malik and Singh, 1995).

Table 2. Yield (t/ha) of rice under various tillage options in rice and wheat

Tillage in wheat

Tillage in Rice

Mean

Wet Rotary

Wet Harrow

Dry Rotary

Dry Harrow

ZT

Zero Tillage

7.27

7.21

6.55

6.14

5.66

6.57

Rotary Tillage

7.64

7.52

7.21

7.25

5.38

7.00

FIRBS

7.64

7.45

7.05

7.62

4.88

6.93

Conventional

7.74

7.68

7.38

7.44

5.48

7.14

Strip till drill

7.44

7.57

6.97

7.05

5.72

6.95

Mean

7.55

7.49

7.03

7.10

5.43

 

CD (0.05)

 

Tillage in rice

Tillage in wheat

Interaction

   

0.43

0.21

0.48

Time and fuel savings under various tillage options for growing rice and wheat

Rice can be transplanted after puddling involving single tractor operation or dry field preparation by rotary tiller followed by ponding of water and/or planking. These practices only require two tractor passes compared to 6-9 operations currently being used by most farmers. In the presence of crop residues, green manuring or excessive weeds, we may require one more tractor operation by either harrow or rotary tiller with and without planking. For comparison, 7 tractor operations i.e. cross harrow, cross cultivator, planking, puddling harrow and planking were considered for conventional field preparation. The time and fuel consumption for various tillage options are presented in Table 3. Savings of 23 to 67% in time and 31 to 72% in fuel were recorded compared to conventional practice in rice when rotary tillage was followed alone or in combination with harrow and/or planking.

For wheat, farmers on an average undertake 12 operations with various tillage equipments (cross harrow, cross cultivator, pre-sowing irrigation, cross harrow, cross cultivator, planking, broadcasting of seed and fertiliser, cross cultivator followed by planking) for growing wheat by the broadcast method. The operations can be reduced to 10 by drilling instead of broadcasting seed and fertilisers followed by cross cultivator and planking. A number of tractor passes are eliminated by employing the improved tillage machines like zero-till drill (ZTD) and rotary-till drill (RTD) as the sowing is accomplished in a single tractor operation without and with field preparation. The extent of savings by using drill after conventional field preparation was around 22% for time and 19% for fuel over the broadcast method. The corresponding figures for zero tillage were about 86 and 92% and for rotary tillage about 77 and 79%. The adoption of these resource conservation technologies (ZTD and RTD) over large areas in the Indo-Gangetic plains will lead to enormous savings in terms of time, fuel and foreign exchange spent to import oil.

Table 3. Tractor operations, time and fuel consumption for growing rice and wheat

Tillage Options

Tractor operations

Time h/ha

Fuel
L/ha

Time Saving
%

Fuel Saving
%

Rice

Wet Rotary

1

2.02

11.66

67

72

Wet Rotary and planking

2

2.62

15.53

58

62

Dry harrow and wet Rotary

2

3.09

19.14

50

54

Dry and wet Rotary

2

4.23

25.98

32

37

Dry, wet Rotary and planking

3

4.74

28.52

23

31

Conventional tillage

7

6.19

41.31

--

--

Wheat

Zero Tillage

1

1.71

5.94

86

92

Rotary tillage

1

2.90

16.00

77

79

Conventional tillage (Drill)

10

9.74

61.17

22

19

Conventional tillage (Broadcast sowing)

12

12.50

75.53

--

--

Conclusion

The study indicates that zero or rotary tillage can be adopted for harvesting similar or higher yield of wheat at lower cost. For growing rice puddling may not be required as almost similar yield can be harvested under unpuddled transplanted conditions. However, zero tillage transplanted rice gave lower yield. In system perspective, zero or rotary tilled wheat followed by dry or wet rotary is the best option for getting higher yields. The study also shows that substantial savings of time and fuel can be made by adopting alternate tillage practices to make the production of rice and wheat more cost effective.

References

Walkley, A and Black, IA (1934). An examination of the Degtjareff method for determining soil organic matter and a proposed modification of chromic acid titration method. Soil Science 34, 29-38.

Nayar VK and Gill M S (1994). Water management constraints in rice-wheat rotations in India. Pp. 328–338 in ‘Wheat in heat stressed environments: irrigated, dry areas and rice-wheat farming system’, ed. by DA Saunders and GP Hattel. CIMMYT, Mexico DF.

Paroda RS (1997). Integrated nutrient management for sustainable agriculture. Keynote address delivered at the inaugural session of the ‘FAO-IFFCO International Seminar on IPNS for Sustainable Development’, 25 November 1999, New Delhi.

Shankaranarayana HS (1982). Morphology, genesis and classification of soils of Indo-Gangetic plains. Pp. 467–473 In ‘Review of soil research in India, Part II‘, 12th International Soil Science Congress, New Delhi, India.

Singh RB (2000). Environmental consequences of agricultural development: a case study from the Green Revolution state of Haryana. Agricultural Ecosystems and Environment 82, 97–103.

Yadav RL (1998). Factor productivity trends in a rice-wheat cropping system under long-term use of chemical fertilisers. Experimental Agriculture 34, 1–18.

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