Chemical fertilizer has been excessively used for high yield of citrus around the world, especially in China; meanwhile, it deteriorates the citrus orchard soil environment. To resolve the conflict, the use of organic fertilizer provides a promising solution. However, the data about organic fertilizer used in citrus orchard is rarely available. Here, four treatments including CK (no fertilizer), CF (chemical fertilizer), OF + CF (chemical fertilizer reduction combined with organic fertilizer; application of N, P₂O₅, K₂O fertilizer and organic fertilizer is 0.564, 0.236, 0.336 and 10 kg/plant), and BF + CF (chemical fertilizer reduction combined with bioorganic fertilizer; application of N, P₂O₅, K₂O fertilizer and bioorganic fertilizer is 0.508, 0.320, 0.310 and 10 kg/plant) were performed in a ‘Ponkan’ (Citrus reticulata Blanco) orchard to evaluate the effect of organic fertilizer on citrus yield, growth, soil properties etc. when nutrients of fertilizer of each treatment were equal except CK. The data obtained in 2019 and 2020 showed that both OF + CF and BF + CF were beneficial to improve soil fertility (soil physicochemical and microbe properties) and citrus growth physiology (growth, nutrient and photosynthesis), alleviate NO₃⁻-N leaching, and promote yields. Comprehensive evaluation indicated that BF + CF was more effective than OF + CF. Together, organic fertilizer has the potential to substitute partial chemical fertilizer with improvement in soil properties, growth physiology, and yield of citrus.

Bimetallic metal–organic frameworks (MOFs) are promising for controlled-release fertilizers (CRFs), yet the deliberate use of metal-ion competition to tune their properties is a nascent and powerful strategy. This study presents one of the first systematic investigations into harnessing competitive coordination, specifically between Fe^{3 +} and Zn^{2 +} with a tannic acid ligand, to modulate the structure and sustained-release performance of bimetallic MOFs. A monometallic Fe-MOFs (Compound 1) and a bimetallic Fe/Zn-MOFs (Compound 2) were synthesized. While their compositions were analogous, the dominance of Fe^{3 +} during coordination, due to its hard acid character and stronger chelation tendency, dictated the framework formation, leading to distinct properties for Compound 2, including smaller crystal sizes and altered morphology. These structural modifications resulted in an enhanced nutrient release profile for the bimetallic system, achieving a higher cumulative releaseparticularly in acidic conditionswhile sustaining effective release for 30 d in various soils. Release kinetics was best described by diffusion-based models (Higuchi and Ritger–Peppas). In pot experiments with bok choy, Compound 2 significantly improved plant growth and nutrient uptake, outperforming both the monometallic MOF and the conventional fertilizer. These findings conclusively demonstrate that metal-ion competition is a critical, underexplored lever for rationally designing efficient bimetallic MOFs-based CRFs, providing a foundation for their development in sustainable agriculture.

Waterborne polymer coated controlled release fertilizers (CRFs) are highly valued for their potential to enhance nitrogen use efficiency (NUE) and reduce fertilization labor costs. However, their application in crops with long growth periods, such as rice and maize, is limited by inadequate coating strength and suboptimal hydrophobicity. Inspired by the hydrophobic and anti-fouling structure of lotus leaf cuticles, this study biomimetically modified waterborne polyacrylate-coated urea (PACU) using natural bio-wax including rice bran wax (RBW), candelilla wax (CAW), bees wax (BW) and carnauba wax (CW), along with paraffin wax (PW) as a control. The modifications significantly extended nutrient release duration by 22 d compared to unmodified PACU, with CW providing the longest duration, followed by CAW, BW, RBW, and PW. Additionally, the modification of BW, CAW, and CW exhibited superior hydrophobicity and affinity to polyacrylate coatings, while the inferior hardness and toughness of PW compromised its controlled release performance. Field trials demonstrated that CW-modified CRFs effectively controlled nutrient release in rice and maize, resulting in a 7.2% increase in rice yield and a 37.9% increase in maize yield, as well as an 18.7% improvement in NUE compared to conventional fertilizers. These findings offered a novel approach for hydrophobic modification of waterborne polymer coatings, thereby enhancing the performance and applicability of waterborne polymer coated CRFs in long-season crops.