The loss of N in farmland is an important cause of agricultural non-point source pollution, which seriously impacts the aquatic environment.  A two-year (2017–2018) experiment was conducted to investigate the characteristics of runoff and N losses under different tillage practices.  Taking downslope ridge planting and cross ridge planting as the experimental treatments, the characteristics of surface runoff, interflow, and N losses in sloping farmlands with yellow soil were studied throughout the maize growth period.  As the rainfall increased, the surface runoff and interflow also increased.  The surface runoff and N losses in the surface runoff of downslope ridge planting were significantly higher than those of cross ridge planting.  The interflow volumes and N losses in the 0–20 and 20–40 cm soil layers of the cross ridge planting were significantly higher than those of the downslope ridge planting.  The total N (TN) losses from surface runoff accounted for 54.95–81.25% of the N losses from all pathways.  Therefore, we inferred that surface runoff is the main pathway of N losses.  Dissolved total N (DTN) was the main form of N loss under different tillage measures, as it accounted for 55.82–94.41% of the TN losses, and dissolved organic N accounted for 52.81–87.06% of the DTN losses.  Thus, we inferred that dissolved N is the main form of N loss.  Future research must focus on the prevention and control of the N losses during the maize seedling stage to reduce the environmental pollution caused by ammonium N through runoff.

Organic phosphorus (P) is an important component of the soil P pool, and it has been proven to be a potential source of P for plants.  The phosphorus utilization efficiency (PUE) and PUE related traits (tiller number (TN), shoot dry weight (DW), and root dry weight) under different phytate-P conditions (low phytate-P, 0.05 mmol L^–1 and normal phytate-P, 0.5 mmol L^–1) were investigated using a population consisting of 128 recombinant inbred lines (RILs) at the vegetative stage in barley.  The population was derived from a cross between a P-inefficient genotype (Baudin) and a P-efficient genotype (CN4027, a Hordeum spontaneum accession).  A major locus (designated Qpue.sau-3H) conferring PUE was detected in shoots and roots from the RIL population.  The quantitative trait locus (QTL) was mapped on chromosome 3H and the allele from CN4027 confers high PUE.  This locus explained up to 30.3 and 28.4% of the phenotypic variance in shoots under low and normal phytate-P conditions, respectively.  It also explains 28.3 and 30.7% of the phenotypic variation in root under the low and normal phytate-P conditions, respectively.  Results from this study also showed that TN was not correlated with PUE, and a QTL controlling TN was detected on chromosome 5H.  However, dry weight (DW) was significantly and positively correlated with PUE, and a QTL controlling DW was detected near the Qpue.sau-3H locus.  Based on a covariance analysis, existing data indicated that, although DW may affect PUE, different genes at this locus are likely involved in controlling these two traits.