Phosphorus efficiency of naturalized Chilean white clover in a grazed field trial


Correspondence to: H. Acuña, Instituto de Investigaciones Agropecuarias, INIA, Centro Regional de Investigación Quilamapu, Avenida Vicente Méndez 515, Casilla 426, Chillán, Chile.



Nine naturalized white clover populations and two cultivars (Huia and Will) were evaluated at two soil phosphorus ( P ) levels (6 and 20 P mg kg−1) to characterize them for DM production and P efficiency, and to facilitate the selection of suitable genotypes to produce cultivars for P-deficient marginal soils. The study was carried out in Chile during 2007–2010 under field grazing conditions using a randomized complete factorial block design with three replicates. The clover was grown with perennial ryegrass. Botanical composition and herbage DM production were recorded, phosphorus concentrations in soil and in clover and ryegrass herbage were determined, and P absorption (PAE) and P utilization (PUE) efficiency were calculated. Population 8-1-X yielded more DM under the low than under the high soil- P level and was the highest yielding clover in the low soil- P treatment. It also had the highest PAE (0·6 kg P ha−1 per mg kg−1 Olsen P) under low P availability. Dry-matter yield of 9-2-X was statistically similar to 8-1-X and Huia at low P level; however, because of its lower P absorption, it had the highest PUE (455 kg DM ha−1 per kg ha−1 absorbed P). Furthermore, the highest yield of ryegrass occurred when grown with 8-1-X, and this combination gave the maximum total yield. These two populations have potential for inclusion in breeding programmes.