PARADIGM SHIFT FOR ENHANCING RICE PRODUCTIVITY

S.S. Rathore

ICAR Research Complex for NEH Region, Nagaland Centre, Nagaland

INTRODUCTION

The State of Nagaland lies between 25⁰60’ and 27⁰ 40’ latitude north of the equator and between the longitudinal lines 93⁰ 20’ and 95⁰ 15’, having an area of 1657.9 thousand ha. The state comes under eastern Himalayan agro climatic zone. More than 90% terrain of the state is hilly. Paddy is the staple food crop of the state and almost grown in the entire area from plain land (valley land) to hill slopes along an altitudinal gradient of 2500 m elevation. Medziphema valley is also known as rice bowl of the state and is one of the most important regions of rice cultivation in the state. There exists great diversity in rice cultivation in respect of cultivars being used, soil and climatic conditions, geographical terrain, management practices to be followed. The productivity of rice in country and in north eastern regions including Nagaland is low as compared to world average productivity.

            Rice is originated in the hot and humid tropics where heavy rains and floodwater create an aquatic environment for at least part of the year. This has led to the general perception that rice can be grown only in flooded fields. Rice cultivation has been categorized into many types based on the edaphic, atmospheric climatic conditions and management practices. Two systems i.e., lowland and upland cultivation are widely known practices of rice cultivation world wide. Nearly a sixth of rice is grown under upland conditions. There are 18 wild species distributed mainly in Asia, Africa and America. Of the two cultivated species Oryza sativa is cosmopolitan, while Oryza glaberrimn is confined to Africa. There are two major sub species or races that are indica and japonica. Jhum land paddy can be broadly categorized into upland paddy. Like upland paddy, jhum paddy is dependent on rainwater and no effort has been made to store the rain water in the field. Jhum paddy which is a very old practice mainly followed in the hilly terrain, that constitutes around 56.20% area .Wet terrace rice cultivation is recent intervention in hilly terrain and now widely followed by Angami tribe in Kohima district, and Chakesang in Phek district. The wet rice cultivation is mainly practiced in the Medziphema and Jalukie valleys of the state. In Nagaland, three types of paddy cultivation has evolved from time immemorial: (i)  Jhum paddy cultivation; (ii)  Wet Rice cultivation (WRC) and, (iii)  Wet Terrace Rice cultivation. (WTC). Jhum land and terrace rice cultivation is mainly practiced in the hilly terrain areas.

Rice occupies an area of 43.90 million hectares in the country with 85.20 million tones production and productivity of 1938 kg/ha (Agricultural Statistics at a Glance, 2004).The north eastern region accounts for 7.8 per cent of the total rice area in India while its share in rice production is only 5.9 per cent. The average rice productivity of 1.4 t/ha is below the national average of 1.9 t/ha (Table 1). The comparative statistics of area, production and productivity of rice cultivation in Nagaland with respect to National and world scenario is given in Table 1. On an average the yield per hectare of WRC/TRC is more than the average yield under upland jhum paddy, which is reported as 17.41 q/ha and 13.02 q/ha, respectively. Data given in Table 2 reveal that upland jhum can also produce a yield level as close to high input WRC/TRC, provided the same level of input and support of agronomic practices. It is clearly evident from the productivity level of these two system from Dimapur District, which is 17.64 q/ha under WRC/TRC and 16.92 q/ha under upland jhum paddy.

Table 1: Comparative rice production statistics

Basic statistics of NER, 2002, GOI, NEC Secretariat, Shillong

Fig: Jhum paddy field often sown as                                Fig: Pani Kheti in Jalukie valley

        mixed crop

Fig: Terrace rice cultivation in Phek district

           The area, production and productivity under Jhum paddy are 85.300 MHa, 111.10 MT and 13.02 q/ha respectively, which is roughly similar to upland rice agro-ecosystem. This jhum paddy comprises about 56.50 % of area and 49.26 % of production of rice cultivation in the state. State of Nagaland constitutes 0.50 % of the area and 0.25 % of the production of rice in the country.

Table 2: District wise statistics of upland jhum and wet terrace rice cultivation in the Nagaland (2003-04).

Statistical Hand Book of Nagaland, 2004

WRC-Wet Rice Cultivation, TRC-Terrace Rice Cultivation

Dimapur is benefited highly with the contemporary advancement in agricultural practices and improved infrastructure expansion in the state and due to this reason, the acerage under upland jhum paddy is least in Dimapur. District wise acerage under paddy in descending order can be mentioned as Dimapur, Kohima, PhekWokha, Mokokchung, Tuensang, Zunehabato and Mon. The highest productivity under upland jhum paddy in Dimapur district is due to better cultivation practices and inputs in terms of irrigation, fertilizer, seed and plant protection etc.

CROPPING SYSTEMS

Rice based cropping systems of Nagaland

                Paddy is the staple food crop in all areas of the state and the cropping system is broadly  monocropping type. Sporadically in different areas diverse crops as maize, ragi and some of the vegetables are taken along with paddy without any row arrangement. In upland jhum paddy production system  it is more appropriate to call it as crop system instead of cropping system because of the fact of raising of single crop in most of the upland jhum areas. More over depending upon the behavior of rainfall the second crop may also be included in the cropping system in some of the district.

Table 4: Dominant paddy based cropping system under different agro climatic conditions of Nagaland.   

Directorate of Agriculture, Government of Nagaland.

Table 5:  Main existing cropping system in upland jhum paddy can be enumerated as-

There is shift in the existing cropping system from monocropping to intensification of paddy based cropping system in recent past due to increasing population pressure and improvement in the basic agricultural infrastructural facility in the state. This intensification is happening in both temporal and spatial dimension, i.e., by practicing more and more area under sequence cropping and intercropping including mixed cropping. It is the mixture of crops which is usually grown with paddy, during Kharif season. Some of the vegetables are also grown with upland paddy.

SOIL MANAGEMENT AND TILLAGE OPERATION

Soils range from highly fertile to highly weathered, infertile and acidic. Soil management for rice production in the state varies from highly modernized hill agriculture, i.e., terraced form of rice cultivation to primitive jhum cultivation. The usual practice of jhum is burning of all bio-resources during the dry month of the year. In most of the places the dried stubbles are incorporated in the soil either as such or half burnt  and by this way the whole of the crop residue will become the part of soil management in jhum areas. This is one of the sustainable on farm management of soil fertility. The whole of burnt, semi burnt biomass is dumped in the particular jhum area in order to supplement some of primary, secondary and micronutrients. The soils of jhum area are rich in organic carbon; it varies from 2-4 % in different jhum area; low to medium in nitrogen, fairly high in potash. There is problem of available phosphorus management of this soil as fixation of phosphorus is a problem. The phosphorus fixation occurrs due to acidic soil reaction which makes more availability of soluble Fe and Al which further react with available phosphorus and fix it in insoluble form in the soil.

The soil manipulation for land preparation and sowing is minimum. Generally no ploughing is done to prepare the field for sowing of the next crop either manually or by any mechanical means. In upland jhum paddy areas, the tillage operations are adopted in the form of highly reduced, energy saving form of zero tillage. Field preparation and other soil manipulation operations for creation of suitable tilth are not in practice. Land clearing is done by burning of crop residues and other woody and herbaceous plants. The only tillage operation which is being done is during sowing of the crop. In sowing operations too tilling is not done by any plough but by a very indigenous implement known as alluppi or Naga khuraphi. By alluppi a small shallow pit is dug at irregular space to make the area for sowing of the seed of upland paddy.

VARIETALS SCENARIO

The popular crop varieties of rice in Nagaland are Teke, Ranjit, Bahadur, Ketaki joha, Naga special 1, 2, 3, 4.  Upland rice growers generally prefer local cultivars that do not respond well to improved management practices but these are well adapted to their environments and produce grains that meet local needs. The one strain known as wonder rice is claimed to be highest yielding and tallest plant type in the world. But the large scale field trials are yet to be conducted for the same.

SOWING AND SEED PRIMING

The most prevalent method of sowing under upland jhum cultivation is the direct sowing of presoaked seed or after some sort of seed priming. As the germination under direct sowing is not up to the desired level, it necessitates going for presowing treatment. The purpose of priming is to reduce the germination time, make germination occur over a short period and improve stand and percentage germination.

INTERCULTURAL OPERATIONS AND HARVESTING

In most of the rice ecosystem of the state, the weeding is mainly done by manual means. Other than weeding generally no intercultural operation is being done in the paddy field. Irrigation management is only done in the wet terrace and Pani Kheti areas and generally no water management is usually done in jhum paddy which is depending entirely on natural course of rain water. The cultivars so selected are long duration and crop sown in June- July becomes ready for harvest in month of December –January. Harvesting is done by picking up of mature panicles and leaving straw in the field itself in jhum paddy and in most of the TRC/WTRC field.

A. Rice crop contingency plan for aberrant weather conditions

            The increasing uncertainty of weather conditions word wide is causing great negative impact on crop production. The below normal rainfall of this year has resulted in great loss in yield. This necessitates for contingency crop planning.  In traditional rice growing rain-fed areas where rains are likely to be delayed and where a normal transplanted rice crop is ruled out, short duration upland rice varieties or those rice varieties that are suitable for direct seeding either in dry or wet condition and subsequent flooding are recommended by direct seeding.  The uncertainties in weather conditions affect the rice production badly. There is need to evolve a standard site specific contingency crop planning to cope up in better way with the unfavorable weather contortions.

Table 7:  Contingency crop planning under various weather situations

B. WEED MANAGEMENT IN RICE

Weeds are the major problem in rice field and this problem is more serious in upland condition including jhum land. Following recommendations are made for weed control and management:

 (i) Only use good clean seed (free of weed seeds); (ii) Improved leveling improves water control and can significantly reduce weed pressure; (iii) Tillage practices should be timed (e.g., 10-14 days between passes) such that weeds have time to germinate in between tillage operations and thus be killed by the succeeding operation. Timely tillage reduces weed pressure; (iv) Rotate crops and weed control practices to decrease weed intensity; (v) Select varieties that are more competitive and smothering efficiency; (vi) Transplanting gives the plant a competitive advantage against weeds; (vii) Direct seed in rows to facilitate hand or mechanical weeding; (viii) Higher populations of rice increase shading and reduce weed growth, but may increase crop lodging; (ix) Combined with good leveling, maintenance of a water layer in the paddy reduces the pressure of many weeds; and (x) Prevent weeds from growing along bunds and irrigation canals - weed seed can pass along the irrigation system to your field.         

C. SOIL FERTILITY MANAGEMENT

          Soil fertility is the major factor which is responsible for wide scale popularity of jhum farming in the state. There is need for inclusion of recent advances made in the soil fertility management. In this regard site specific soil fertility management is one of the most important methods to deal with effectively with the decline of the same in the state.

Many of the nutrients required by rice plants come from soil. But this supply of nutrients is typically insufficient to meet the nutrient requirements for high rice yields. The use of supplementary nutrient sources is consequently essential to fill the deficit between crop needs for nutrients and the supply of nutrients from soil and available organic inputs.

Site-specific nutrient management (SSNM) is an approach to feeding rice with nutrients as and when needed. The application and management of nutrients are dynamically adjusted to crop needs of the location and season. The SSNM approach aims to increase farmers' profit through: i) increased yield of rice per unit of applied fertilizer; ii) higher rice yields; and iii) reduced disease and insect damage. The features of SSNM are:

(1) Optimal use of existing indigenous nutrient sources such as crop residues and manures; and

(2) Application of nitrogen (N), phosphorus (P), and potassium (K) fertilizer is adjusted to the location- and season-specific needs of the crop.

 2. Soil acidity and toxicity of elements in rice field

              Increasing acid load in the soils of Nagaland due to heavy soil erosion, leaching of bases (Ca, Mg, Na), runoff  which is eventually happening because of heavy rainfall. Increasing soil acidity led to vast imbalance of soil nutrients, some are becoming deficient while others are becoming toxic. The toxicity of Fe, Cu and Al creates unfavorable conditions in the soil for the growth of the paddy crop. To manage the toxicity of Fe, Cu Al and sulphate, it is essential to know the various details of the dynamics of these nutrients in soils and plant system.

With the decrease in pH, the more and more iron is transform into ferrous form which acts as toxic to the rice due availability in higher amount.

II- Aluminum Toxicity

 III- Sulfide Toxicity

(i)       Diverse varieties can provide complementary disease resistance and other positive agronomic effects; (ii) Mixtures of plant genotypes can reduce disease spread; (iii) Mixed pathogen populations may lead to induced resistance; (iv) Diverse varieties may reduce the selection pressure on the pathogen and slow down pathogen evolution (thus increasing the number of years that a variety can remain resistant); and (v) These factors can lead to reduced spray requirements and increased yield.

Need of refined and more inclusive strategy for transfer of agro techniques to the farmers:- The traditional method of transfer of technology as of demonstration and training are good to convince the farmers only when the felt need of the farmers are given due care. Along with these methods, the new extension techniques as Test strip for transfer of promising technology can be tested to visualize more impact of advance techniques on the farmer’s field.

A Test Strip is a strip across a farmer’s field where one input is changed (added, omitted or modified). Treatments within the strip may include a change in planting density, a new variety, or changes in fertilizer or pest management, etc. Test strips are simple to highly visible, easy to apply and offer a simple way to assess a treatment relative to the farmer’s current practice and circumstances. The strip plots are useful tools for demonstrating “new” agro techniques to the farmers.

CONCLUSION

The productivity of rice under wet and wet terrace cultivation is more (19.16 q/ha) than rice under jhum cultivation (15.32 q/ha).The lower productivity of paddy under jhum is due to non adoption of improved agronomic practices as efficient rain water management, no intercultural operation as weeding, improper sowing,  and no taking up sound plant protection measures. The improvement in the productivity level of upland jhum paddy can be improved to a greater extent by making suitable intervention in the existing practices. Among the interventions required in this regards are proper land preparation, seed and sowing including seed priming, participatory breeding work to improve the local strains of upland paddy, suitable blend of traditional knowledge and frontier technologies for ecofriendly low cost pest management. To convince the farmers about new promising agro techniques for wide scale adoption a little extra effort is required. The advances in the extension techniques must be made an integrated part for transfer of technology to the farmers. Along with demonstration, on farm training, new technique as field strip can also be tried to convince the farmers. Considering the acidic nature of the soil the toxicity of some of the elements as Al, Cu, Fe and sulphate is needed to ameliorate to get the good yield from the paddy. The integration of all the techniques for management of pest is the need of the hour due to its cost effectiveness and for maintenance of eco balance. It is quite possible to enhance the productivity level of paddy in the state by following the sound management practices for soil fertility and pest control, etc.

REFERENCES

Agenda notes, Directorate of Agriculture, Government of Nagaland, Kohima, Nagaland

Alam, M.M., Ladha J.K., Rahman Khan, S., Foyjunnessa, Harun-ur-Rashid, Khan, A.H., Buresh, R.J. 2005. Leaf color chart for managing nitrogen fertilizer in lowland rice in Bangladesh. Argon. J. 97:949–959.

Basic statistics of NE Region 2002. North East Council, Government of India, Shillong, Meghalaya.

Director of Agriculture, Rice production and productivity in Nagaland. Paper presented in Seminar on Boro rice and strategy for enhancing rice production and productivity in the Northeast. 23-24 August, 2004.

Statistical Handbook, Millenniums issue Government of Nagaland, 2000, Directorate of economics and statistics, Govt of Nagaland