Four drought-tolerant maize varieties gave between 13 and 38 percent higher yields than a variety that is not drought-tolerant.
For the drought-tolerant varieties, the largest microdose gave about 12 percent more maize than the recommended fertilizer rate, with 54 percent less nitrogen.
Maize sown early gave a 10 percent higher yield than maize sown at the usual time.
Researchers at Université de Parakou in Benin have tested how drought-tolerant maize performs when it is sown at different times and given small doses of fertilizer right next to the plant. The results are published in the journal PLOS One.
Maize is one of the most important crops south of the Sahara. It accounts for half of the cereal production in the region and for 30 percent of the daily calorie intake, according to the study.
How the trial worked
The trial was carried out in 2018 and 2019 at a research station in the village of Ina in northern Benin. The area gets 900 to 1,300 millimeters (about 35 to 51 inches) of rain a year, during a rainy season from May to October. The maize got only rainwater.
The researchers sowed at three times: early in June, at the normal time in early July, and late at the end of July. They compared five maize varieties. Four were drought-tolerant and one was drought-sensitive. They also tested five ways of fertilizing: no fertilizer at all, three different microdoses and the recommended fertilizer rate.
With microdosing, a small amount of fertilizer is placed in the soil near each planting hole. Each planting hole, with two plants, got a few grams of urea and phosphate fertilizer, five centimeters (2 inches) from the hole. The largest microdose equaled 35 kilograms of nitrogen and 8 kilograms of phosphorus per hectare (about 31 and 7 pounds per acre). The recommended rate was 76 kilograms of nitrogen and 13 kilograms of phosphorus (about 68 and 12 pounds per acre).
Less fertilizer gave more maize
All fertilizer treatments raised the yield sharply compared with no fertilizer at all. The smallest microdose gave a 153 percent higher yield. The largest microdose gave a 247 percent higher yield, and the recommended rate 221 percent.
According to the researchers, the largest microdose gave about 12 percent more maize than the full rate in the drought-tolerant varieties. At the same time, it used 54 percent less nitrogen and 38 percent less phosphorus. The middle microdose gave 93 percent of the yield from the recommended rate, with 67 percent less nitrogen.
The fertilizer was also used more efficiently. With the largest microdose, each kilogram of nitrogen gave 84 kilograms of maize. With the recommended rate, each kilogram of nitrogen gave 36 kilograms of maize.
An earlier study by the same research group showed that the largest microdose gave the best return relative to what the fertilizer cost.
Drought-tolerant varieties gave larger yields
All four drought-tolerant varieties gave higher yields than the variety that is not drought-tolerant. The best was TZE-Y, with a 38 percent higher yield. It was followed by TZEE-W with 30 percent, 2008 Syn with 27 percent and 2000 Syn with 13 percent. The drought-tolerant varieties also produced 30 to 54 percent more biomass.
The drought-tolerant varieties yielded at most 2.7 to 3.3 metric tons per hectare (about 2,400 to 2,900 pounds per acre), all with the largest microdose. The variety that is not drought-tolerant reached at most 2.6 metric tons per hectare (about 2,300 pounds per acre), and it needed the full fertilizer rate to do so.
Drought-tolerant varieties are being developed for more crops. In India, researchers have developed rice varieties that can handle both drought and flooding.
Early sowing gave more
Maize sown early gave a 10 percent higher yield than maize sown at the normal time. Late sowing gave 10 percent less. According to the researchers, the difference is probably partly due to how the rain was spread over the season. In 2018, the early-sown fields got 678 millimeters (26.7 inches) of rain during the season, compared with 418 millimeters (16.5 inches) for the late-sown fields.
The highest average yield in the trial was 3.51 metric tons per hectare (about 3,100 pounds per acre). It came from TZE-Y with the largest microdose and early sowing.
The study was carried out by Mouiz Yessoufou, Pierre Tovihoudji, Sissou Zakari and Irénikatché Akponikpè at the HydroModE Lab at Université de Parakou. It was funded by the Africa Climate Leadership Program.
WALL-Y
WALL-Y is an AI bot created in Claude. A human selects the news, WALL-Y writes the text and a human checks the results before publishing.