Genotypic Variations in Potassium Absorption and Utilization by Amaranthus spp.

The kinetics of K+ absorption and the utilization of both applied K and K in a calcareous alluvisol with low available K by different genotypes of grain amaranth (Amaranthus spp.), an ancient pseudo-cereal that produces a large biomass and a rich source of healthy nutrients and mineral elements, were studied by means of ion depletion technique and pot experiments. Grain amaranth had a high affinity for K+ uptake in comparison with corn and cotton. However, there were differences among Amaranthus spp. in K absorption and utilization. Some cultivars such as R104, CX-4, Du001, Hy015 and Hr029 which had a higher rate of K absorption and stronger affinity for K+ were typical varieties with high K-use efficiency (KUE). The results showed that high KUE cultivars grew quickly, possessed stronger ability to take up soil slowly available K and mineral K, and did not respond to K fertilization in the soil with low available K. Correspondingly, grain amaranth cultivars CX-77, Cr024, Vd001, Re003 and Sn003 were relatively low in KUE. Compared with high KUE cultivars, they took up more soil available K and both of their dry matter accumulation and K uptake responded to K applied significantly.

Effect of nitrogen fertilizer on the uptake and utilization of potassium by various rice varieties in purple soil

Nitrogen and potassium are important nutrientelements for rice.Besides supplied by the or- ganic manure,potassium nutrition of ricecomes dominantly from purple soils in Sichuanbasin.Potassium exists abundantly in mineralforms in the purple soils.Availability of soilpotassium for crop depends on the potassiumforms,the uptake ability of crops,and fertiliz-er practices.A pot culture experiment wasconducted to study the kinetics of potassiumuptake in the purple soil(total N 22.64g·kg,total K 24.36g·kg,available N 102.6mg·kg,available K 140.6mg·kg,acidsoluble K 936.0mg·kg,and pH 6.8).Ma-terials used were three Fhybrid rices,Eryou

Research on the Production Efficiency and Utilizing Rate of Potassium Fertilizer for Rape in Yunnan Province

[Objective] This study aimed at investigating the effects of consumption of potassium fertilizer on production and biological characteristics of rape and utilizing efficiency of potassium fertilizer.[Method] Taking 0 kg/hm2 as control,nine consumptions of potassium fertilizer were designed for the experiment using single factor randomized block design with three replications and field experiment in nine rape-producing areas with different ecological types in Yunnan Province.[Result] Appropriately applying potassium fertilizer in Yunnan Province could improve the rapeseed production,the rape production could achieve 3 983-4 151 kg when applied 150-180 kg/hm2 of K2O,which had increased by 4.7-9.1% compared with the control and attained the peak in K165 treatment.When applied 1 kg of K2O,the rapeseed production could enhance 559 kg,the net profit could reach 1 229 yuan/hm2 and the partial productivity of potassium fertilizer could attain 31.32 kg/kg K2O and 3.7 kg/kg K2O,respectively.Applying potassium fertilizer could promote the growth of rape and increase rapeseed production.[Conclusion] The recommended optimal consumptions of potassium fertilizer with high production and high efficiency for rape in Yunnan Province were ranged between 150 and 180 kg K2O/hm2.However,comprehensively considering production and efficiency factors,the consumption of potassium fertilizer in Yunnan Province was around 73.9 kg/hm2,which should be appropriately increased to around 100.0 kg/hm2 in Longchuan,Yulong,Linxiang and other producing areas with similar conditions.

Differences in the Efficiency of Potassium(K) Uptake and Use in Five Apple Rootstock Genotypes

Plants that grow well while accumulating and transporting less potassium（K） perform better than more-sensitive plants when under deficiency conditions, which makes low-K-input and environmentally friendly agriculture possible. We conducted hydroponics and sand culture experiments to evaluate the efficiency of various apple（Malus domestica Borkh） rootstocks in their K uptake and utilization. Five genotypes were selected which are widely used in China- M. hupehensis Rehd, M. prunifolia Borkh, M. robusta Rehd, M. sieversii Roem, and M. rockii Rehd. Plant heights, root and shoot dry weights, and K concentrations were recorded. These genotypes differed markedly in dry weights, absolute and relative K concentrations, absolute and relative K accumulations, and their K efficiency ratio under deficient K conditions. The last parameter, expressed as relative shoot dry weight, was strongly and positively correlated with the other four parameters in each genotype. Therefore, we suggest that this parameter could serve as an index when selecting K-efficient genotypes. In this study, we have determined that M. sieversiiand M. rockii are K-inefficient genotypes; M. prunifolia is K-efficient genotype; M. hupehensis and M. robusta have moderate levels of potassium efficiency.