Direct Seeded Rice (DSR)

Direct Seeded Rice (DSR) in place of the traditional transplanted rice is a way to reduce labor charges for nursery raising, puddling and transplanting. DSR is sown directly into the moist soil like wheat, corn or cotton and does not need continuous submergence so it reduces overall water requirement also. Precision leveling is desirable, it increases water efficiency, improves crop stand and optimize input use.

Advantages of DSR:

·        Labour saving up to 75 %

·        Water saving up to 30 %

·        Early maturity of crop

·        Timely sowing of wheat crop

·        Saving of machinery operations (needed for puddling)

·        Avoids compaction of soil due to puddling

·        Good precursor of zero tillage technology

PRODUCTION TECHNOLOGY

The land should be prepared to produce a leveled seedbed with fine tilth free of weeds.  Fine seed bed ensures better yield because of good germination and crop stand, root proliferation, fertilizer efficiency. Puddling is not done.

Planting Techniques and seed rates:

Sowing is done in moist soils using a wheat drill or 0-til drill calibrated to deliver desired seed quantity keeping 9ʺ row spacing. Fields should be irrigated when nursery planting time begins and properly prepared for planting. Sowing can be done broadcast if drill is not available. In the later case seed should be moistened in water for 8-10 hour to hastened germination. Soaked seed should, however, be dried in shade to avoid stickiness of wet seed for broadcasting. Soaking of seed with fungicide eliminates or reduces seed borne and soil-borne diseases.  The seed rate for direct seeding of fine grain rice varieties should be 10-12 kg and for coarse varieties 12-15 kg per acre. Seed should be sown 2-3cm deep for good crop stand. Placing seed deeper affects emergence. Planting can be done in paired rows 6ʺapart; the distance between paired rows should be 12ʺ apart.

Sowing Time: The best planting time for DSR is 10 to 15 days before crop transplantation. This, coupled with the fact that DSR matures 10-12 days earlier, enables early planting of the following wheat crop. Seeding too early causes crop sterility due to high temperature at anthesis; seeding late exposes the crop to heavy attack of insect pests and diseases. For fine rice, the crop should be sown from end May to 3^rd week of June, and for coarse varieties, mid May to early June.

Fertilizer Application: Adequate and timely application of fertilizer is a prerequisite for good yields. Optimum quantity of fertilizer needed depends on the nutritional status of the fields; however, a generalized   recommendation of fertilizer use consists of 2.5 bags urea, 2 bags DAP and 1 bag potassium sulphate. All P and K, 1/3^rd of N should be drilled along with the seed, the remaining N can be applied in two splits; 1/3^rd after 25 days of sowing and 1/3^rd after 40-45 days. In areas where zinc deficiency occurs zinc must be applied as zinc sulphate (35% Zn) @ 5 kg/acre.

Irrigation Management: Irrigation is  critical in DSR especially at earlier stages. Soil must be kept moist for the first 12 days to ensure complete germination. First irrigation should be applied a days after sowing followed by pre-emergence weedicide one day after 1^st irrigation. If, however, heavy soaking dose is applied first irrigation can be delayed until after emergence. In that case herbicide application should be done in the evening after sowing. DSR crop does not require continuous submergence and can be safely irrigated when hairline cracks appear on the soil. In DSR water is only given to keep soil continuously moist. Moisture stress should be avoided at tillering, panicle initiation, and grain filling stages which are crucial for obtaining higher yields. At these stages it is advisable to keep fields flooded. The last irrigation should be applied 20 days before harvesting.  DSR is an aerobic rice production and may show iron deficiency symptoms in some soils. Flooding or submerging the field correct these symptoms.

Weed Management:

In DSR fields, weeds are a major challenge. Weed control through adequate land preparation, judicious use of water, and use of appropriate herbicides is, therefore, essential. The crop should be kept free of weeds during the first 40-45 days after that weeds will not influence yields adversely. Flooding is very effective in controlling all weeds and avoiding iron deficiency. It is, therefore, advisable to flood fields for 10-12 days after emergence of the crop. Following herbicides can give good weed control applied at proper time and manner.

	Success of DSR depends on  effective weed control

Herbicide	Rate  (ml/acre)	Application (days after planting)
Pendimathalin	800ml	1-2
Clover 20wp	80gm+80ml	20-25

Clover has given good results for weed control in DSR. So it can be used as post emergence herbicide alone in 2applications one after the other as necessary.

Madhana (Dactyloctenum aegyptium) proves a difficult weed extensively found in non-core rice areas. It spreads out fast and can cover wide areas in the field. It can be controlled with Pandimathalin at early stages. If the weed advances its control with rice weedicides is difficult. Puma super, a wheat crop weedicide can provide effective control. Rice crop is, however, sensitive to Puma super, so it should be applied 15-20 after planting when crop has established and Madhana is in early stage. A dose of 225ml/acre should suffice.

Climate change

Anyone walking the face of earth can vouch the changing trends of our climate. Hottest years in the history have been experienced during the past decade. Rain pattern is changing. Erratic heavy rains and resulting floods are occurring more frequently causing massive devastations. All atmospheric indicators are pointing to these disturbing patterns unfailingly. Recorded temperatures during the past century bear ample witness (Fig 1).

Fig 1

These changes and their future trends are of deep concerns to humanity. If the ambient temperatures change what consequences will these have on life, plants and animals, on the planet? Man himself, his crops and livestock will take a certain beating from unfavorable temperatures. These developments threatening humanity and its march forward coupled with fast expanding population represent the tipping of balance of food needs-availability equation. So a concern is dawning on humanity to understand and counter these climate related effects.

Economic progress and population pressure are heavily straining our food base. More and better food is required to feed rising and prospering humanity. Rising heat due to climate change, on the other hand, is threatening food production systems. Besides, direct adverse effect, it would have multi-fold indirect effects also. Glaciers, the vast storehouses of water feeding rivers, are melting (Fig 2) reducing water availability; favorable crop growing areas would squeeze, insect and disease activities would rise posing health hazards and making food production difficult.

Human activities are at the base of all these disturbing trends. Man is devouring natural resources. It is estimated that the current rate of resource use is 1.4 planet equivalent which, naturally, over long time is unsustainable and, in fact implosive. Industry, transport, agriculture are all using natural resources at an accelerated pace and, at the same time, churning out toxic wastes injurious to environment.

Fig 2. Receding Himalayan glaciers

Fossil fuel consumption alone is adding billions of tons of CO₂ annually (Fig 3). Other toxic gases – nitrogen and sulfur oxides, chlorofluorocarbons (CFCs) -  from powerhouses, smelters, chemical and fertilizers industries are accumulating in atmosphere.  Natural gas, diary industry and anaerobic rice cultivation are contributing methane to the environment. All these gases have affected the makeup of gaseous envelop around the earth planet. This atmospheric cover around the earth is a protective screen that obstructs harmful solar radiation reaching the ground. For example, ozone layer in the upper atmosphere screens out much of the harmful UV radiation from sun. Its depletion would increasethe incidence of UV on earth with harmful consequences for humans and other living beings. Natural atmospheric composition was responsible for maintaining a healthy balance of incoming and outgoing radiation which, in turn, maintained a favorable environment for life. Any change in composition would jeopardize this atmospheric ability rendering earth planet inhospitable. This is happening due today. Fuel use in home heating, cooking, transports, and power generation is adding billions of ton of carbon to the air (Fig 3). Its CO₂ contents have risen from 280ppm preindustrial level to over 390 ppm presently. Similarly, nitrogen and sulfur oxides, methane and man-made gases (CFCs) have increased significantly. These gases have affected the radiation exchange capacity of the atmosphere. Most of the incoming solar radiation is in short waves which can pass through the atmosphere. Once on the earth it heats the earth surface and heat is radiated back as infrared in long waves. The infrared is absorbed by these gases and radiated back to the earth surface raising its temperature.  Average earth temperature is 15°C it has already risen by 0.74°C due to  of these gases. These gases, for this reason, are called green-house gases (GHGs) since their net effect is similar to what we experience in green-houses.

Fig. 3 Global carbon emissions

The rising temperatures are injurious to crop and animals. It is estimated that every single degree increase in temperature in Celsius would reduce wheat yields by 7 and rice yield by about 10 percent. So temperature changes, at a time when food demand is increasing  could spell disaster for human survival.

The world is alive to these threats and the two international agricultural organizations - CIMMYT and IRRI - are putting together packages that can sustain agricultural production in unfolding future scenario while reducing fuel consumption and so arresting harmful effects of agriculture on the environment.

Conservation Agriculture

Conservation agriculture (CA) is a protective system of crop production. It endeavors to make a judicious use of land, water and natural resources to maximize crop yields and arrest their deterioration to make agriculture sustainable.  It aims to increase input efficiency to reduce cost of crop production and harmful effects of chemicals and fossil fuels on environment.

CA has sprung to forefront in importance due to climate change. Industrial growth, expanding agriculture and massive energy use are all spewing out harmful gases and chemicals into environment. The composition of atmosphere is changing and water aquifers are polluting. Accumulating CO₂, nitrogen & sulfur oxides and methane in the air are obstructing escaping heat from the earth surface into the space and so raising earth temperature. The rising heat is harmful to life; crops and livestock. Crop yields and livestock productivity would suffer. Heat would affect adversely in many other ways. Current favorable crop production zones would be rendered less favorable; glaciers feeding rivers would shrink and rising heat would increase insect and pathogen activity. So humanity is facing a dilemma; rising food needs and deteriorating food base.

Future agriculture, therefore, should produce abundant food at low rates, conserve natural resources, use inputs efficiently and reduce energy use to arrest environmental degradation. Room for free will is shrinking and man needs to act in unison with nature to avoid catastrophe. Use of natural forces - biodiversity - would be to his advantage. Biodiversity is nature’s means to maintain health of planet and is man’s free but tool to attain his goals. These are the ingredients of CA. CA package is in making but time is not man’s side. So the two international agricultural research organizations - CIMMYT and IRRI – have reviewed the available knowledge and put together a package of practices that can go a long way in adding efficiency, reduce energy and input use and make agriculture sustainable. These practices have, over time, proved their efficacy and so are gaining acceptance worldwide.

CA package includes:

·         Laser leveling

·         Bed planting 

·         Zero-tillage

·         Direct seeding of rice

·         Crop residue management

·         Alternate wetting and drying in rice

·         Site specific nutrient management

·         Balanced fertilizer management

·         Relay, inter and catch cropping

Laser leveling has gained wide acceptance here. By eliminating unevenness in  field it saves more than 20 per cent water and makes irrigation easy and labor saving.

Bed planting of has several advantages. It reduces wheat crop irrigation needs upto 40 percent. Bed planted crop shows less lodging and sunny and aerated conditions in the field promote tillering and reduce disease and insect damage. For this reason, farmers often report yield edge of bed planted wheat crop. A local version of bed planting is also in practice. Farmers prepare the field, broadcast seed and fertilizers and make beds with a ridger. Though less precise yet it shows all advantages of bed planting.

Zero-til planting eliminates preparatory tillage and allows timely planting of wheat after rice. By using remnant moisture it can have water saving element too. The rice residues in the soil conserve moisture, add organic matter, make soil porous, increase biological activities and keep crop environment cool. It, thus, has a heat busting effect.

Direct seeding of rice (DSR) involves seeding crop like wheat without raising nursery or soil puddling. It save 75 per cent labor. Combined with alternate wetting and drying and elimination of puddling it can save large quantity of water. DSR ensure optimum plant population which in nursery transplanted fields is often low. Weeds are, however, serious problems for DSR. It has, nonetheless been successfully demonstrated in Hafizabad district this year. In non-core-rice areas this technology needs to be further refined.

Relay, inter and catch cropping increase system productivity and are means to enhance food availability and raise income. These crops are grown with/in/between other (main) crop(s) and mostly use main crop resources for their growth. So water and input use is maximized. Other elements of CA are intended for same purpose. CA, therefore is a way out to sustain agriculture in rising temperatures and receding waters.

CSISA Bulletin Issue 17

This issue includes briefs of  3rd Technical Working Group meeting of CSISA, Pakistan held in Faisalabad, Farmers’ CA and seed production training and Farmers’ meeting-cum-training program
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