Phosphorus response and efficiency of four adventive annual clovers grown in a New Zealand high country soil under glasshouse conditions

Abstract

Maintaining and increasing legume abundance is a critical component of pastoral intensification, increasing nitrogen inputs to nitrogen deficient New Zealand high and hill country pastures and improving feed quality. Establishment and persistence of traditionally sown legume species white clover (Trifolium repens) and subterranean clover (T. subterraneum) is often limited in summer-dry high country. In contrast, naturalized, adventive annual pasture legume species such as cluster clover (T. glomeratum), haresfoot clover (T. arvense), striated clover (T. striatum) and suckling clover (T. dubium) persist on low fertility, summer-dry high and hill country slopes, although little is known about the edaphic requirements of these species. A glasshouse study was conducted to determine the response and efficiency of these four pasture legume species to increasing levels of available phosphorus (P) in a typical, low fertility, acidic New Zealand high country soil, comparing against white clover and subterranean clover as 'reference' species. Trifolium subterraneum was the most productive species (4.4 g dry matter [DM]/pot) and T. striatum yielded the least (0.8 g DM/pot). The order of greatest yield DM response was T. subterraneum T. arvense T. repens T. dubium ] T. glomeratum T. striatum, while the P application rates at which maximum yield occurred varied between species. Mean shoot P uptake was highest for T. subterraneum and lowest for T. striatum (24.1 and 3.8 mg P/pot, respectively). P-response efficiency by species was in the order of T. subterraneum T. arvense T. glomeratum T. repens T. dubium T. striatum. Implications for low input, extensive grazing systems in high and hill country are discussed. Trifolium arvense and T. glomeratum show potential for further P response investigation under field conditions.

Dry matter and nutritive value responses of native, naturalised and sown pasture species to soil Olsen P

“…The naturalised clovers T. campestre, T. glomeratum, and T. dubium had critical external P requirements similar to subterranean clover but a lower growth potential. This concurs with Maxwell et al (2013), who found that under both low-and high-P conditions the yield of T. subterraneum exceeded that of T. glomeratum, T. dubium and T. striatum. The native grasses A. scabra and R. caespitosum had the lowest critical values in the field experiment, but were of low nutrient value as livestock feed.…”

“…There is evidence of considerable variation in plant response to increased fertility both between and within species (e.g. Gourley et al 1993;Hill et al 2010;Maxwell et al 2013;Haling et al 2016aHaling et al , 2016bHaling et al , 2018. The largest differences are in growth potential under non-limiting nutrition, but there are also differences in the critical P level at which 90% of maximum yield is achieved.…”

Phosphorus response and optimum pH ranges of twelve pasture legumes grown in an acid upland New Zealand soil under glasshouse conditions

“…The soil Olsen P at which maximum yield was achieved differed substantially between legume species, but values were high in all cases. Species differences were likely driven by genetic adaptations to low phosphorus environments (Maxwell et al, 2013) and therefore each have different P requirements and P use efficiencies for growth (Raven et al 1992, Syers et al 2008). Tagasaste and 'Nomad' white clover peaked at the lowest Olsen P's, while Lucerne and balansa and white clover required very high Olsen P for peak yield.…”

“…Key factors driving the presence of legumes in the field include soil fertility and moisture availability Moot 2010, 2014). Soil phosphorus (P) and pH are often low in dryland, both of which have negative impacts on pasture legumes (Maxwell et al 2013). However, very little information exists in literature on P efficient and pH tolerant legumes which may provide alternatives to white clover.…”

The phosphorus dilemma in organically farmed grasslands – are legume presence and phytodiversity incompatible?

“…Trifolium repens, the commonly known and used clover species in permanent grasslands of the temperate zone (Käding and Werner 2003) and our most dominating legume species, was found to require P application rates of 200-250 mg P kg −1 soil to attain 97% of maximum yields in pot experiments in New Zealand (Moir et al 2012). This resulted in P Olsen concentrations of 46-78 mg kg −1 at the end of the study (Maxwell et al 2013). Davis (1991) calculated critical P concentrations in grassland legumes based on the optimal P concentrations for 90% of their maximum yields in a field study in New Zealand.…”