Author
Norton, Lloyd | |
VENTURA, E - UNIV QUERETARO, MX | |
CASTRO, CELSO - IAPAR, BRAZIL | |
RAMSIER, CLIFF - AG SPECTRUM, IOWA | |
TORRES, ELENO - NATL SOYBEAN CTR, BRAZIL |
Submitted to: Proceedings Brazilian Soil Science Society
Publication Type: Proceedings Publication Acceptance Date: 5/10/2004 Publication Date: 7/15/2004 Citation: Norton, L.D., Ventura, E., Torres, E., Castro, C., Araujo, A., Ramsier, C. 2004. A modified no-till system to optimize yields. In: Proceedings Brazilian Soil Science Society, July 25-30, 2004, Santa Maria, Rio Grande do Sul, Brazil. 2004 CDROM. Interpretive Summary: Technical Abstract: Conservation tillage has evolved since the 1960's when no-tillage (NT) involved the direct drilling of seeds into the soil. The adoption of NT was limited although the economic advantages of a one pass seeding operation were clear due to other problems. Some advantages of NT include erosion control, less fuel, time and equipment and the increased life time of expensive power equipment compared to conventional European systems. In the northern corn-belt, USA, the acreage of NT corn has been steadily declining in spite of extensive efforts to increase the acreage to control erosion. A problem that has been identified by farmers with conventional NT is the non-uniform germination caused by uneven seeding depth. Many NT planters tend to have difficulty in cutting heavy residues and sometimes leave seeds on the soil surface. The residue left in immediate proximity to the plants that do emerge can harbor a wide range of disease and pests, thus affecting the plants that do emerge. With NT, nutrient management and placement has been difficult for farmers with respect for N and P and micronutrients. Pre-plant addition of N leads to large losses through volatilization, de-nitrification or other processes. Also, corn needs available P very early in the developmental stage to produce proteins needed for maximum yield potential. Side-wall compaction caused by the NT coulters cutting through the soil containing clay when placing the seeds is another problem. Over a wide range of soil moisture conditions this can occur and limit the horizontal growth of the roots needed to forage for nutrients and water for the newly germinated plants. Considering all the above, the objective of this paper is to describe a new and improved NT based system developed with farmers, researchers and agri-business to overcome some of these problems with NT and present some results from on farm and research plots. We modified existing NT equipment in order to overcome some of the problems described above. They included improvements in: air/soil water management, mechanical systems and soil chemistry. Soil and water management was optimized through the use of both chemical and mechanical means. This included the use of gypsum to improve infiltration, control erosion and reduce surface sealing. The mechanical system included using a NT row planter and the addition of row cleaners to remove residue in an approximately 10 cm wide row without disturbing the soil in front of the seed trench opener.This unit replaces the front residue cutting coulter which is removed. Secondly, the addition of pumps, tanks and pressure regulators to meter liquid fertilizer both placed directly onto the seed or at a critical distance from the seed as needed (e.g. N and S for corn). Addition of fertilizer is performed by addition of seed firmers inside the trench opener to place the fertilizer in the trench bottom. These fertilizers are designed so that they will not harm the seeds when onto them and the firmers do not crush the seed. This addition is a critical step in the process because it precisely places all the seeds at the same depth and provides starter fertilizer to maximize uniform germination and growth. Compaction near the seed is reduced with Case-IH style press wheels by preventing vertical compaction near the seed trench by placing the down pressure weight away from the seed trench. Sidewall compaction is avoided through using spader wheels behind the seeding operation helping to cover the seed. The disturbed area is smoothed by a twisted chain which also pulls some of the residue back over the worked area to help reduce erosion. Gypsum (5MT/ha) is added directly over the disturbed surface with the insecticide drop boxes or surface broadcast over the entire area to control erosion. The amount needed depends on the amount of rainfall or irrigated water r |