Tillage & Crop Establishment: Zero-tillage

Conventional tillage operations in north-west Indo-Gangetic Plains including India and Pakistan generally require 6 to 8 harrowing followed by 2-3 planking before the wheat crop is sown after harvesting the rice crop. This entails high costs, results in delayed sowing, and affects the wheat yield adversely. Agricultural engineers at the Govind Ballabh Pant University of Agriculture and Technology, India have developed a Zero Till Ferti-Seed Drill based on the design of an original New Zealand drill.

The drill is an inverted T-type furrow opener that opens a narrow slit in rice fields and plants 9 rows of wheat at 20-cm distance in one pass. The equipment costs $300 and works well in non-combine harvested areas where loose straw is not left on the surface. More research and equipment development is needed where loose crop residues are present.

A different version of the above Pantnagar drill called a ‘Strip-Till Drill’ is being used on a four-wheel tractor in the Indian Punjab. In this system the rotovator tills only a narrow strip of soil where the seed is placed and the remaining area remains untilled. In Pakistan engineers are developing other zero-till drills.

DFID Project on Tillage
The Department for International Development (DFID) was supporting a 3-year Project on "Harnessing Tillage by Nutrient Management Interactions using Participatory Approaches to Improve Rice-Wheat Systems Productivity and Sustainability", which started in April, 1999. This project was carried out in several sites in Bangladesh, India, Nepal, and Pakistan. Summary of some of the experiments (below) shows that Zero Tillage is here to stay and it has vast potential to conserve natural resources.

Trials in India
Based on the tremendous expansion of zero-till in Haryana (India), the State Department has agreed to include this practice in their package of practices recommendations. This is the first State in the region to do so and will go a long way to help expand area even more. Farmers are purchasing their own drills and local manufacturers are flat out keeping up with demand. The farmers plant their own fields with this equipment and then make it available to other farmers on a rental basis enabling all farmers to experiment.

Five sets of farmer fields are being monitored with one acre field using zero till and one acre with conventional practice. Farmers have agreed to continue with the same practice for 3 years although they really want to shift the entire farm to zero till.

Average wheat yields for the 5 monitored sites were 5.56 tons/ha. for zero till and 5.20 tons/ha for conventional. In one site out of 4, however, the yield of zero tilled filed was less than conventional. The highest yield on zero till plot was 6.82 tons/ha. while that for conventional tillage was 6.0 tons/ha. The extra yield in zero till was the result of timelier planting and fewer weeds. The lead investigator (Dr RK Malik of Haryana Agricultural University) at this site says:

"The wheat yield in the resistance (herbicide resistant Phalaris minor) affected area in Haryana has gone up to 4.35 tons/ha. in 1999-2000 compare to 3.45 tons/ha. in 1994-95 and 1995-96 (based on 300+ fields being monitored in addition to the DFID fields). On the contrary, the yield in the unaffected area has gone up from 3.7 to 3.9 tons/ha. Even if the gain of 2 quintals is accounted for by favorable weather condition, the weed resistance management (effect of zero till combined with new herbicide use) has accounted for major gains in wheat productivity.

He further adds: "The studies on long-term trials on zero till at Uchana and Teek have shown that the population of Phalaris minor decreased over the 3 year period. In all these plots alternate herbicides including clodinafop, fenoxaprop or sulfosulfuron were used during 3 years. The reduction in population is because of the combined effect of herbicides and zero tillage. The yield of wheat in both permanent trials increased over 3 years period under zero till."

Environmental Benefits

• improving water use efficiency and conservation (important as water becomes scarcer);
• reducing the need for applying herbicides;
• helping to control erosion;
• reducing the amount of N that "leaks" into the environment;
• providing environmentally friendly options for managing crop residues;
• reducing soil compaction; and
• bettering soil physical structure over time.

Trials in Pakistan
In Pakistan two institutions are involved with the Project, the Punjab On-Farm Water Management (OFWM), Lahore and the scientists from the National Agricultural Research Centre (NARC), Islamabad. The latter provide the technical input and the former the field and farmer activities. An excellent annual progress report for one of the villages for 1999-2000 entitled "Pilot testing of Resource Conserving technologies under the DFID project" has been printed by OFWM and is available if required. NARC has also provided a technical report on soils and biotic factors. OFWM has also contracted a local consultant to produce a video of the various resource conserving technologies being promoted. This will be available during December 2000.

Wheat yields were not significantly different in the farmer fields between the zero till or conventional tillage paired plots and averaged over all fields 5.20 and 5.08 tons/ha., respectively, for zero till and conventional in the Muridke village. The main reason for this was that the two treated paired fields were planted on the same day, except at one site. In that site zero till did significantly better due to timelier planting. Next year all fields will get this advantage. However, there was savings in water for the first irrigation, less weeds and savings in cost (US$25-40/ha). Farmers are excited about these benefits and acreage will increase next year from the 153 acres planted this year by farmers in the village.

In the Mona project villages/sites wheat yields were 4.62 tons/ha. (zero till) versus 4.31 tons/ha. (conventional) for the 6 monitored fields. They also did a survey of other fields and yields were 4.33 tons/ha. for zero till and 3.70 tons/ha.for normal. Water use efficiency increased from 1.10 to 1.43 kg/m3 in favor of zero till. Fertilizer efficiency also increased from 21.6 to 27.6 kg grain/kg fertilizer. Economically, costs were reduced by US$38/ha through zero till. The report prepared made the statement "with the use of less irrigation water and less fertilizer application we can get more crop production by adopting resource conserving technologies."

Trials in Nepal
The zero till drill (Pantnagar Drill) was also used in Bhairahawa this last wheat season in several fields owned by a single farmer. The results shown in Haryana were evident in Bhairahawa. Although, there were some weed problems and failure to apply fertilizer properly, the farmer at Gargati still reported good harvest (2600 kg/ha) as compared his land prepared by local methods of plowing. While the work is extremely limited, it has showed the same promising results as it has in India and elsewhere. Through custom hiring this technology might be able to benefit small farmers as well. In rice wheat long-term monitoring in Rupandehi the use of tractor for plowing is increasing. For the tractor owners/farmers it would be a simple task to replace the nine-tine cultivator with a zero-till drill.

RWC Publications covering Tillage and Crop Establishment aspects