Adjusting sowing dates enhance the efficiency of climate and nutrient resources for spring maize

  Objectives  Temperature, light, and precipitation are the key meteorological factors affecting the growth and development of maize. This study was designed to understand the relationship between key meteorological factors and N absorption, crop yield to maximize the efficiency of climate and N resources of spring maize.

  Methods  The spring maize cultivars, Xianyu 335 (XY335) and Zhengdan 958 (ZD958), were used as test materials in a two-year field experiment in Jilin Province. The treatments were three sowing dates: April 24th, May 4th, and May 14th, representing early, mid, and late sowing dates. The dry matter and N accumulation, N translocation rate, and grain formation before and after anthesis were investigated. We combined the Hybrid-Maize model with local meteorological data to comprehensively simulate and evaluate the yield difference among treatments. Further, light and temperature resources were matched at different sowing dates.

  Results  For cultivar XY335, the dry matter accumulation in the early, middle, and late sowing dates were 21233, 21249, 20311 kg/hm²; the N accumulation was 184.2, 192.5, and 171.1 kg/hm²; N transfer rates were 35.1%, 45.7%, and 35.8%; and the rates of N contribution to grain were 19.4%, 29.6%, and 23.9%. For cultivar ZD958, the dry matter accumulation in the early, middle, and late sowing dates were 21031, 20637, and 20405 kg/hm²; N accumulation was 173.7, 163.4, and 154.9 kg/hm²; N transfer rates were 39.2%, 36.4%, and 25.6%; and the contribution rates of N transfer to grain were 32.7%, 25.4%, and 13.7%, respectively. XY335 had the highest yield under the middle sowing date, 9.9% and 17.4% higher than early and late sowing dates. ZD958 had a higher yield under early sowing date, 8.6% higher than the late sowing date. The yield of XY335 was mainly affected by the daily average temperature during the reproductive growth stage. In contrast, the yield of ZD958 was closely related to the total solar radiation of the whole growing period and the days of the vegetative growth period. The yield difference was mainly related to the dry matter and N accumulation across the VT-R6 period. XY335 had improved N transport efficiency after flowering, requiring a high average daily temperature in the reproductive growth stage. ZD958 needed longer days for high yield accumulation throughout the growth period.

  Conclusions  Yield differences are caused by sowing dates and cultivars due to high dry matter and N accumulation after anthesis. This situation increases N transfer to grains and consequently improves yield. XY335 recorded an efficient N accumulation and transfer rate after anthesis. Our results suggest that the middle sowing date (May 4th) is suitable for the XY335 cultivar. However, the yield accumulation of ZD958 requires a long-term for high cumulative radiation, implying that early sowing (April 24th) is suitable for this cultivar.