Responses of Phaseolus calcaltus to lime and biochar application in an acid soil.

Luhua Yao,Lei Huang,Zhibin He,Dan Liu,Xiaoting Li,Yanjun Guo,Xiangyu Yu,Yang Li,Xiao Zhao,Lin Kang,Xuefeng Zhang,Dengke Wang,Qianlin Xiao

doi:10.7717/peerj.6346

Abstract

IntroductionRice bean (Phaseolus calcaltus), as an annual summer legume, is always subjected to acid soils in tropical to subtropical regions, limiting its growth and nodulation. However, little is known about its responses to lime and biochar addition, the two in improving soil fertility in acid soils.Materials and MethodsIn the current study, a pot experiment was conducted using rice bean on a sandy yellow soil (Orthic Acrisol) with a pH of 5.5. The experiment included three lime rates (0, 0.75 and 1.5 g kg−1) and three biochar rates (0, 5 and 10 g kg−1). The biochar was produced from aboveground parts of Solanum tuberosum using a home-made device with temperature of pyrolysis about 500 °C.Results and DiscussionThe results indicated that both lime and biochar could reduce soil exchange Al concentration, increase soil pH and the contents of soil microbial biomass carbon and microbial biomass nitrogen, and enhance urease and dehydrogenase activities, benefiting P. calcaltus growth and nodulation in acid soils. Lime application did decrease the concentrations of soil available phosphorus (AP) and alkali dispelled nitrogen (AN), whereas biochar application increased the concentrations of soil AP, AN and available potassium (AK). However, sole biochar application could not achieve as much yield increase as lime application did. High lime rate (1.5 g lime kg−1) incorporated with low biochar rate (5 g biochar kg−1) could obtain higher shoot biomass, nutrient uptake, and nodule number when compared with high lime rate and high biochar rate.ConclusionLime incorporated with biochar application could achieve optimum improvement for P. calcaltus growing in acid soils when compared with sole lime or biochar addition.

Highlights

Rice bean (Phaseolus calcaltus), as an annual summer legume, is always subjected to acid soils in tropical to subtropical regions, limiting its growth and nodulation
Teutscherova et al (2017) reported that biochar could result in more pronounced changes in N cycle than lime application which could be of especially high interest in intensively managed soils with high N inputs. These results suggested that biochar application might be an alternative way besides traditional liming in improving acid soil fertility for green manure legume growth
Soil pH and the concentrations of soil exchangeable Al and available nutrients were significantly influenced by lime and biochar applications and their interactions (Table 1)

Summary

Introduction

Rice bean (Phaseolus calcaltus), as an annual summer legume, is always subjected to acid soils in tropical to subtropical regions, limiting its growth and nodulation. Little is known about its responses to lime and biochar addition, the two in improving soil fertility in acid soils. The results indicated that both lime and biochar could reduce soil exchange Al concentration, increase soil pH and the contents of soil microbial biomass carbon and microbial biomass nitrogen, and enhance urease and dehydrogenase activities, benefiting P. calcaltus growth and nodulation in acid soils. Lime incorporated with biochar application could achieve optimum improvement for P. calcaltus growing in acid soils when compared with sole lime or biochar addition. Responses of Phaseolus calcaltus to lime and biochar application in an acid soil. Green manure legumes could reduce soil bulk density and enhance total porosity, macropores and large mesopores (Sultani et al, 2007)

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Discussion

Conclusion