Combining Organic Fertilizer With Controlled-Release Urea to Reduce Nitrogen Leaching and Promote Wheat Yields

Abstract

Soil deterioration, low nitrogen use efficiency (NUE), and environmental risks caused by excessive chemical N fertilizer use are key factors restricting sustainable agriculture. It is extremely critical to develop effective N management strategies that consider both environmental and agronomic benefits. From 2017 to 2019, a field experiment was conducted to assess the effects of combinations of organic fertilizers (OF, provided at 30, 50, and 70% of the total applied N) and controlled-release urea (CU) on the NUE, N leaching and wheat yield compared with the effects of urea and CU. The results suggested that OF released N slowly in the early stage and showed a significant residual effect, while CU released N quickly in the first 2 months. The OF substitutes with 30–50% CU increased wheat yield by 4.2–9.2%, while the 70%OF+30%CU treatment showed no significant difference relative to the urea treatment. The average maximum apparent NUE recovery (50.4%) was achieved under the 50%OF+50%CU treatment, but the partial factor productivity was not affected by the N type. As the OF application rate increased, the total carbon content increased, and the total N value decreased. The NO3−-N and NH4+-N concentrations in the OF+CU treatments were lower before the jointing stage but higher from the grain-filling to mature stages than those in the urea treatment. NO3−-N and NH4+-N were mainly concentrated in the 0–60-cm layer soil by OF substitution, and N leaching to the 60–100-cm soil layer was significantly reduced. Hence, the results suggest that the combination of 30–50% OF with CU synchronizes absorption with availability due to a period of increased N availability in soils and proved to be the best strategy for simultaneously increasing wheat production and reducing N leaching.

Effects of Organic Substitution on the Yield and Quality of Apples and Residual Nitrate-N Leaching in Soil

“…Moreover, our study showed that high organic substitution ratios (60% and 100%) significantly reduced apple yield, which might be caused by the lack of synchronization between plant nutrient requirements and organic fertilizer nutrients release [37,38] and the suppressed symbiosis relationship between plants and soil microorganisms [39,40]. Additionally, under field conditions, crop growth relies mainly on available mineral nutrients, making a high organic substitution not ideal for increasing crop yields in the short term [41]. Although 200% organic substitution could improve the apple yield further than other OS treatments, it is not a cost-efficient fertilization plan for farmers.…”

Organic Fertilizer with High Nutrient Levels Affected Peanut-Growing Soil Bacteria More Than Fungi at Low Doses

“…Soil α-glucosidase plays an important role in soil by catalyzing the hydrolysis of glucosidic bonds, providing energy and essential nutrients for plants, and thereby promoting plant growth and development [62,63]. OF application in our experiment had relatively little impact on most soil enzymes, which was attributed to the low dose of the OF application [64,65]. OF amendments supply specific amounts of available nitrogen, phosphorus, carbon, and other sources to the oligotrophic environment, altering both biotic and abiotic (temperature, moisture, pH, nutrient availability) factors.…”

Growth, Yield and Photosynthetic Performance of Winter Wheat as Affected by Co-Application of Nitrogen Fertilizer and Organic Manures

“…As described by [ 10 , 14 ] the (Pn) photosynthesis rate, (Gs) stomatal conductance, (Ci) Intercellular CO 2 absorption, and (Tr) transpiration rate of winter-wheat crop under nitrogen levels, nitrogen ratios, and N timings were observed with the use of Li-6400 convenient photosynthesis method (LI-COR Inc., Lincoln, NE, USA), prepared with an LED leaf chamber. From each treatment, two fully prolonged flag leaves plot −1 from each treatment of the winter-wheat crop were selected at jointing, flowering, and grain-filling stages to determine the photosynthesis traits.…”

“…Late season or splitting applications of N fertilizer are common methods to increase grain yield and nitrogen-use efficiency. Plant biomass was superior under splitting N applications (applied at the returning green stage and jointing stage) lower than below total N applications at the tillering stage [ 10 ]. While splitting fertilizer application needs extra labor, the present fertilization technique is usually used on crops below conventional farming practices [ 11 ].…”