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Primary Uses: |
Grain |
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Planting: |
Upland rice may be started in a nursery
and transplanted but more commonly is direct seeded much like wheat
with little or no irrigation. |
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Seeding Rate: |
Because all areas are direct seeded, weeds and poor stand establishment are significant problems.
Seed rate for Jefferson planted by drilling is 90-100 lbs/A,
broadcast is 110-120 lbs/A and 120-130 lbs/A when water planted. |
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Fertility: |
The efficiency with which applied N is absorbed by the rice crop varies greatly among MVs and environments. In most cases, inefficient plant recovery of applied N is the largest constraint to high agronomic efficiency. For irrigated rice, uptake efficiency ranges from 20 to 60% of the applied N although average efficiency is between 30 and 40% in most areas. Low efficiency reflects poor agronomic management and the dynamic nature of N in the soil-floodwater system, which leads to gaseous losses through
NH3 volatilization and denitrification. Avoiding N inputs in excess of crop
needs at any point during the growing season is the key to optimizing N use efficiency and minimizing gaseous losses . Hence, the timing, rate, and method of application have a large impact on efficiency. Several split applications of N are needed to achieve an N supply that approximates plant demand. |
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Insects: |
Many species of organisms inhabit rice
fields. Most of these organisms are not harmful. For example, some 500 species of arthropods (insects and spiders) may appear in a
rice field in a given season, but only a very few are a potential
threat. Most are beneficial or innocent, and include a wide range of predatory and parasitic natural enemies that contribute to keeping the insect pest organisms in check. |
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Diseases: |
Seed rot and seedling blight are
important problems in the seedling stages. Other important
diseases are Rice blast (Pyricularia grisea), Kernel smut (Tilletia
barclayanna), Sheath blight (Rhizoctonia solani),
Stem rot (Sclerotium oryzae), Narrow brown leaf spot (Cercospora
janseana), Panicle blanking complex, Black sheath rot (Gaeumannomyces
graminis var. graminis), and False smut (Ustilaginoidea
virens). Jefferson is resistant to Blast; moderately
resistant to Sheath blight, Brown leaf spot and Narrow leaf spot;
but susceptible to Stem rot. |
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Harvest: |
In the US, rice is harvested directly
with self-propelled combines and dried artificially before storing
or milling. |
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Comments: |
Weeds are an almost universal companion of rice in the tropics. In many situations, weed growth
ins prolific and weeds are a major constraint on crop yield. The direct loss in rice production due to weeds in farmers fields in Asia is reported to average about 20%, with losses reaching 40-100% where weeds are not controlled. Weeding is a major production cost, with estimates of
50-150 person days per hectare required for manual weeding, depending on the number of weedings and type of rice culture. For many farmers, weeding requires the greatest labor input during the agricultural cycle, labor that is often not available when weeds are most damaging to the crop. Upland rice more than any other crop shows the ravages of lack of proper weeding. Sometimes, when the land is too weedy the crop is abandoned.
TCS | |
