Evaluation of Low Phosphorus Tolerance of Rice Varieties in Northern Ghana
Bibliographic record
Abstract
<p>Phosphorus (P) deficiency is a major constraint to upland rice production on highly weathered, low activity clay soils in the humid zones of West Africa. There is a paucity of information on the short-term fertilizer P effects on rice on these soils. A field experiment was conducted in 2011 to determine the response of twenty-four (24) upland rice cultivars to fertilizer Phosphorus (P) applied at 0 and 60 kg P ha<sup>−1</sup>. An uncultivated field at SARI research area with available P (Bray 1) P content of 3.0 mg/kg was used for the experiment.</p> <p>The ploughed area was divided into two plots with one plot for +P and the other for -P treatment. Each of the 24 varieties was allocated three rows and spaced at 20 x 10 cm in four replications. The varieties were randomized for each replicate and planted on 2<sup>nd</sup> July 2011 at one seed per hill. Pre-emergence herbicide Pendimethaline 400 g/l (Alligator) was applied at 3.2 L/ha two days after planting followed by one hand weeding. For the (-) P plot, the entire field received N at 60 kg/ha as Sulphate of ammonia and K<sub>2</sub>O at 60 kg/ha as Muriate of Potash. For the (+) P plot, fertilizer was applied at NPK 60-60-60 kg/ha from Sulphate of ammonia, Triple superphosphate and Muriate of potash, respectively. For each plot, the N was split applied.</p> Results showed that the plants that received P were more vigorous and healthier. There was significant variety effect on number of tillers per plant (NOTPP), days to 50% flowering (DFF), days to maturity (DTM), dry weight of biomass (DWOB), number of panicles per plant (NOPPP), and grain yield per plant. Similarly, there was significant phosphorus effect on number of tillers per plant (NOTPP), days to 50% flowering (DFF), days to maturity (DTM), dry weight of biomass (DWOB), number of panicles per plant (NOPPP), and grain yield per plant. There was generally no interactive effect of variety by fertilizer except for DFF and DTM. The number of tillers per plant ranges from 3 – 16 with the overall mean without P application being 4 while overall mean with P application was 9. When P was applied, the number of days to 50 % flowering reduced from 86 days to 79 days. Days to maturity (DTM) was also reduced from 118 to 111 on average by P application. The varieties that were most tolerant to low P were ITA 257, Nerica 3 and TOX 1011-4-A2. The grain yield of ITA 257 remained the same whether P was applied or not. This is the variety that is best adapted to low P. We concluded that rice growth and yield components were affected by Phosphorus application. Plants that received phosphorus flowered and matured earlier. They also accumulated higher biomass and grain yield. ITA 257, Nerica 3 and TOX 1011-4-A2 were most tolerant to P deficiency.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".