|Fageria, N -|
|Knupp, A -|
Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 11, 2013
Publication Date: May 1, 2014
Citation: Fageria, N.K., Baligar, V.C., Knupp, A.M. 2014. Macronutrients use efficiency and changes in chemical properties of an oxisol as influenced by phosphorus fertilization and tropical cover crops. Communications in Soil Science and Plant Analysis. 45:1227-1246. Interpretive Summary: Cacao is established on newly cleared forestland with wide row spacing and such planting and lack of vegetative cover leads to soil degradation due to loss of soil and nutrients by erosion. Establishment of legume cover crops in early cacao planting could reduce soil loss by erosion and improve soil fertility. Success of the cover crops in early cacao plantations is depended on the level of available phosphorous and other essential macro and micronutrients. In this paper we report the influence of applied phosphorus fertilizer on various nutrient uptake efficiency parameters of macro and micronutrients by fourteen tropical legume cover crops. This research helped to identify nutrient efficient cover crops suitable for early cacao plantations and further gave indications on effects of cover crops and phosphorous fertilization on changes in soil chemical properties. Cacao growers could use this information in selection of suitable legume cover crops to improve ground vegetative cover in early stages of cacao establishment there by prevent soil and nutrient loss by erosion and further improve soil fertility there by increasing the sustainability and yield potentials of cacao plantations. This research also provided needed information which will be useful in managing soil fertility of tropical soils under cacao with phosphorous fertilization and suitable legume cover crop.
Technical Abstract: Cover crops are important components of copping systems due to their beneficial effects on soil physical, chemical and biological properties. A green house experiment was conducted to evaluate influence of phosphorus (P) fertilization on nutrient use efficiency of 14 tropical cover crops. The P levels tested were 0 (low), 100 (medium) and 200 (high) mg kg-1 of soil. The cover crops tested were: Crotalaria breviflora, Crotalaria breviflora, Crotalaria spectabilis Roth, Crotalaria ochroleuca G. Don, Crotalaria juncea L., Crotalaria mucronata, Calapogonium mucunoides, Pueraria phaseoloides Roxb., Pueraria phaseoloides Roxb., Cajanus cajan L. Millspaugh, Dolichos lablab L., Mucuna deeringiana (Bort) Merr., Mucuna cinereum L., and Canavalia ensiformis L. DC. Agronomic efficiency (shoot dry weight per unit P applied), physiological efficiency (shoot dry weight per unit of nutrient uptake) and apparent recovery efficiency (nutrient uptake in the shoot per unit nutrient applied) were significantly varied among cover crops. Agronomic efficiency decreased with increasing P levels. Overall, physiological efficiency of nutrient uptake was in the order of P > S > Mg > Ca > K > N >.Similarly, apparent recovery efficiency was in the order of N > K > Ca > Mg > P > S. Different recovery efficiency in cover crops can be useful in selecting cover crops with high recovery efficiency which may be beneficial to succeeding crops in the cropping systems. The P X cover crops interactions were significant for soil extractable Ca2+, P, CEC, Ca saturation, Ca/K ratio and K/Mg ratio, indicating that cover crops change these soil property differently under different P levels. Thus, cover crops selection for different P levels is an important strategy for using cover crops in cropping systems in Brazilian Oxisols.Optimal values of soil pH, soil Ca and Mg contents, H+Al, P, CEC, base saturation, Ca saturation, Mg saturation, and K saturation were established for tropical cover crops grown on an Oxisol.