Abstract:
Objectives The Shiyang River basin of Hexi region is short in water recourses and rich in light and heat resources, the utilization efficiency of water and fertilizer in agricultural production is generally low. We studied the possibility of coordinating the natural and water and nutrient resources through regulating the sowing date of maize.
Methods A field experiment with complete block design was carried out in the Shiyang River Basin Agricultural and Ecological Water-Saving Experimental Station of China Agricultural University. The treatments were composed of three sowing dates, namely S1: (2018–04–10), S2 (2018–04–20), S3 (2018–04–30), two irrigation rates, i.e. 80% ETc (I80), 100% ETc (I100) (ETc was the crop evapotranspiration), and four nitrogen application levels, i.e. N0, N120 (120 kg/hm2), N180 (180 kg/hm2), N240 (240 kg/hm2). The nutrient uptake and water use efficiency of maize were measured at the key growing stages, and the yield was recorded at harvest.
Results Sowing date had a significant effect on the duration of each growth stage of spring maize, and the number of growing days decreased with the delay of sowing date. Nitrogen application had a significant effect on indexes except water consumption. Leaf area index, dry matter accumulation and grain yield all increased with the increase of irrigation water and N application rate, and decreased with the delay of sowing date. The yield in treatment S1I100N180 was the highest (16830 kg/hm2) and was 7.35% higher than that in S2I100N240 (15678 kg/hm2) and 12.55% higher than that in S3I100N180 (14954 kg/hm2). The water use efficiency (WUE) increased with the amount of N fertilizer and irrigation. The WUE in treatment S1I100N180 was 3.1 kg/m3, which was 12.32% higher than that in S1I80N240. The partial productivity of nitrogen fertilizer (PPNF) decreased with the increase of N fertilizer rate. The PPNF in treatment S1I100N180 was 93.5 kg/kg, which was 4.9% lower than that in S1I100N120, but the yield was increased by 42.65%.
Conclusions Comprehensively considering the yield and water and fertilizer utilization efficiencies, early sowing (April 10) is good for full use of fertilizer and water resources. Under early sowing and fully irrigation, the highest yield of spring maize can be achieved at lower N rate of 180 kg/hm2. The combination has obvious fertilizer-saving effect in spring maize production under the tested conditions.
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