Availability study of once quantitative fertilization in summer maize using fertilizer tablets

【Objectives】 Single fertilization has been approached for decreasing the cost of fertilization in crop production by choosing the form of fertilizers. The availability of flaky fertilizer tablets containing a certain amount of NPK nutrients was tested for the purpose. 【Methods】 According to nutrient requirement of summer maize under a target yield, urea, mono-ammonium phosphate and potassium chloride were mixed in rational proportion and compressed into flaky tablets weighted 7.0 g each. Two pieces of the flaky fertilizer tablets contained the demanded nutrient amount for one summer maize plant. At the seedling stage of summer maize, two pieces of the flake fertilizer were buried 10 cm deep in between two plants with 15 cm apart, thus, the fertilizers were applied around every plant. Field experiments were conducted in Shandong and Henan provinces, the effect of flaky fertilizer (T1: two fertilizer tablets containing N 4.00 g, P2O5 1.72 g and K2O 1.43 g, were placed at seeding stage in between two plants and 15 cm apart from each other) was compared with conventional fertilization (T2: with the same nutrient imput, one top dressing at seedling stage, the other one in bumpet stage), slowly-release fertilizer(T3: containing 52% of slow-realse nitrogen double coated with sulfur and resin, same nutrient amounts with the flaky fertilizer and once top dressed inside ditches 15cm apart from plants) and no N fertilizer (T4: no N fertilizer but all the P and K top dressed like T3) in grain yield, dry matter accumulation, nitrogen metabolism, N, P and K nutrient accumulation of summer maize.【Results】 The results show that the yields are increased by 15.1%-19.5% and 13.8%-16.1% respectively by applying the N fertilizer in Hebi and Heze areas. Compared with the conventional fertilizer application, the precision fertilization improves leaf nitrate reductase activities by 7.45% and 5.57% respectively at the trumpeting and silking stages, and the glutamine synthetase activities are improved by 9.88% and 6.18%. The N, P and K nutrient accumulation amounts of summer maize plants are increased by 3.4%-4.1%, 3.7%-7.0% and 2.7%-3.9%, the N agronomy efficiency and N fertilizer use efficiency are increased by 1.24 kg/kg and 3.41 percentage points respectively, and the average yield is increased by 2.5%. 【Conclusions】 The precision fertilization improves leaf nitrate reductase and glutamine synthetase activities of summer maize at the trumpeting and silking stages, promotes the N, P and K nutrient absorption and utilization, and increases the yield and nitrogen use efficiency to some extent. These results are the same as the slow-release fertilizer by single application as base fertilizer, and the precision fertilization realizes the aim of single application, high yield and high fertilization efficiency of summer maize.