Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Micro-elements Research Center, College of Resource and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Hubei Provincial Engineering Laboratory for New Fertilizers, Huazhong Agricultural University, Wuhan, 430070, China.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Micro-elements Research Center, College of Resource and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Hubei Provincial Engineering Laboratory for New Fertilizers, Huazhong Agricultural University, Wuhan, 430070, China.
J Environ Manage. 2020 Aug 15;268:110610. doi: 10.1016/j.jenvman.2020.110610. Epub 2020 May 14.
Phosphorus (P) is one of the most restrictive essential elements to crop growth and development due to less availability in the soil system. Previous studies have reported the synergistic effects between molybdenum (Mo) and P fertilizer on P uptake in various crops. However, an induced long term effect of Mo on soil P dynamics in the rhizosphere and non-rhizosphere has not been reported yet in leguminous crops. In this study, a long term field experiment was conducted to explore the P transformation characteristics and bioavailability in Mo-deficient (-Mo) and Mo-enriched (+Mo) soil under leguminous (broad bean-soybean) cropping system. The results indicated that long-term Mo application increased the plant dry matter accumulation (14.23%-35.27%, for broad bean; 24.40%-37.46%, for soybean) from March-September. In rhizosphere soil, the percent decrease in pH (8.10%) under +Mo treatment of the soybean crop was recorded more during September as compared to broad bean crop. Under Mo supply, HO-Pi fraction increased up to 28.53% and 43.67% while for NaHCO-Pi this increase was up to 5.61% and 11.98%, respectively in the rhizosphere soil of broad bean and soybean, whereas, residual-P exhibited the highest proportion of P fractions. Moreover, compared with -Mo, +Mo treatments significantly increased the soil acid phosphatase (broad bean = 17.43 μmol/d/g; soybean = 28.60 μmol/d/g), alkaline phosphatase (broad bean = 3.34 μmol/d/g; soybean 6.35 μmol/d/g) and phytase enzymes activities (broad bean = 2.45 μmol/min/g; soybean = 5.91 μmol/min/g), transcript abundance of phoN/phoC genes and microbial biomass P (MBP) in rhizosphere soil. In crux, the findings of this study suggest that long term Mo application enhanced P bioavailability through increased available P, MBP, P related enzymes activities and their genes expressions which may represent a strategy of Mo to encounter P deficiencies in the soil system.
磷（P）是作物生长和发育最受限制的必需元素之一，因为在土壤系统中磷的可用性较低。先前的研究报告了钼（Mo）和磷肥在各种作物中对磷吸收的协同作用。然而，在豆科作物中，钼对根际和非根际土壤磷动态的长期诱导效应尚未报道。在这项研究中，进行了一项长期田间试验，以探索在豆科（蚕豆-大豆）种植系统下缺钼（-Mo）和富钼（+Mo）土壤中磷的转化特征和生物有效性。结果表明，长期施用钼增加了植物干物质积累（蚕豆为 14.23%-35.27%，大豆为 24.40%-37.46%），从 3 月至 9 月。在根际土壤中，大豆作物的+Mo 处理下 pH 值下降 8.10%，9 月比蚕豆作物更为明显。在钼供应下，HO-Pi 分数增加了 28.53%和 43.67%，而对于 NaHCO-Pi，蚕豆和大豆根际土壤的增加分别高达 5.61%和 11.98%，而残余-P 则表现出最高的磷分数比例。此外，与-Mo 相比，+Mo 处理显著增加了土壤酸性磷酸酶（蚕豆=17.43 μmol/d/g；大豆=28.60 μmol/d/g）、碱性磷酸酶（蚕豆=3.34 μmol/d/g；大豆 6.35 μmol/d/g）和植酸酶活性（蚕豆=2.45 μmol/min/g；大豆=5.91 μmol/min/g），根际土壤中 phoN/phoC 基因和微生物生物量磷（MBP）的转录丰度。总之，本研究结果表明，长期施用钼通过增加有效磷、MBP、P 相关酶活性及其基因表达来提高磷的生物有效性，这可能代表了钼在土壤系统中应对磷缺乏的一种策略。
