The soil ecosystem has been severely damaged because of the increasingly severe environmental problems caused by excessive application of phosphorus (P) fertilizer, which seriously hinders soil fertility restoration and sustainable farmland development. Shoot P uptake (SPU) is an important parameter for monitoring crop growth and health and for improving field nutrition management and fertilization strategies. Achieving on-site measurement of large-scale data is difficult, and effective nondestructive prediction methods are lacking. Improving spatiotemporal SPU estimation at the regional scale still poses challenges. In this study, we proposed a combination prediction model based on some representative samples. Furthermore, using the experimental area of Henan Province, as an example, we explored the potential of the hyperspectral prediction of maize SPU at the canopy scale. The combination model comprises predicted P uptake by maize leaves, stems, and grains. Results show that (1) the prediction accuracy of the combined prediction model has been greatly improved compared with simple empirical prediction models, with accuracy test results of R 2 = 0.87, root mean square error = 2.39 kg/ha, and relative percentage difference = 2.71. (2) In performance tests with different sample sizes, two-dimensional correlation spectroscopy i.e., first-order differentially enhanced two-dimensional correlation spectroscopy (1Der-2DCOS) and two-trace 2DCOS of enhanced filling and milk stages (filling-milk-2T2DCOS)) can effectively and robustly extract spectral trait relationships, with good robustness, and can achieve efficient prediction based on small samples. (3) The hybrid model constrained by the Newton-Raphson-based optimizer's active learning method can effectively filter localized simulation data and achieve localization of simulation data in different regions when solving practical problems, improving the hybrid model's prediction accuracy. The practice has shown that with a small number of representative samples, this method can fully utilize remote sensing technology to predict SPU, providing an evaluation tool for the sustainable use of agricultural P. Therefore, this method has good application prospects and is expected to become an important means of monitoring global soil P surplus, promoting sustainable agricultural development.

Rice is threatened by ineffective inputs of water and fertilizers. Therefore, we detected the effect of soil clay content on plant physiological traits and their relationships to phosphorus (P) utilization -efficiency of rice under different irrigation options. Thus, our experiment was conducted in a two -factor randomized complete block design. The first factor was irrigation method, including three choices: alternate wetting/critical drying (AWCD) (50% drying), alternate wetting/sharp drying (AWSD) (30% drying), and alternative wetting/minor drying (AWMD), (10% drying). The second factor was soil clay amount, with three levels at 65, 50, and 30%, corresponding to SHC, SMC, and SLC. The root 's growth and activity were lower in AWCD x SLC than in AWMD x SHC. While the former treatment decreased the P content in soil, the latter increased their availability. The glutamine synthetase (492.5 mu mol g -1 h -1 ) was lower in AWCD x SLC than in AWMD x SHC at 1006.1 mu mol g -1 h -1 , leading to the increase of oxidative cell damage. The optimal P nutrition improved plant growth under AWMD x SHC. The AWCD x SLC led to the minimum agronomic efficiency of P (PAE, 13.67 g/g) and the apparent recovery efficiency of P (PARE, 1.55%). However, the maximum values of PAE (44.05 g/g) and PARE (21.45%) were detected in AWMD x SHC. This study suggests that increasing soil clay content encourages the growth, yield, and P uptake of rice under alternate wetting/minor drying irrigation. The study has excellent application potential, providing technical support for precision water and P fertilizer management of rice.