Djajadi
Indonesia Research Institute for Tobacco and Fiber Crops Jl. Raya Karangploso PO Box 199 Malang, Indonesia
Abstract
Sandy soil for growth media of physic nut in Situbondo, East Jawa has low soil fertility. In this field study, the effect of addition of clay and organic matter with or without mulch on soil properties was conducted from May until November 2010. The treatments consisted of (1) Sandy soil (as control), (2) Incorporation of sandy soil with 10% clay and 1,6% organic matter, (3) Sandy soil covered with mulch and incorporated with 10% clay and 1,6% organic matter. Crotalaria juncea was used as a source of organic matter and mulch. The results showed that incorporation of sandy soil with 10% clay and 1,6% organic matter and mulch increased soil chemical properties of sandy soil which were expressed by increasing soil C-organic, N, P and K contents by 46%, 18%, 73% dan 48%, respectively. The treatmet also improved soil biological properties indicated by more population of soil fungi and bacteria growth on the media. As consequence the growth of physic nut was betterr than that grow on sandy soil.
Keywords: clay, Jatropha curcas L., mulch, organic matter, physic nut, sandy soil, soil properties
Introduction
Potential bio-energy crop Jatropha curcas L (physic nut) is best suitable planted on sandy soils because the plant needs well aerated soils and it is intolerant of waterlogged conditions (da Schio, 2010). However, this natural property of sandy soil can cause problems in their use for agricultural production. The sandy soil was inherently low in all aspects of soil fertility and has a capacity to retain water and applied nutrients (Farrington and Campbell 1970). On the other hand, in order to support a high biomass production physic nut indicates a high demand for nitrogen and phosphorus fertilization (Daey Ouwens et al., 2007). One strategy to support the growth of physic nut on sandy soil is by improving soil fertility.
Among soil properties, CEC, pH organic C and clay have significant effect on the availability of nutrients. Soils which have high amounts of organic matter and moderately weathered clays tend to have high CECs. As soils become highly weathered, the CEC of the soil decreases. Sandy soils, too, generally have lower CEC values. This is due to the lesser surface of sandy particles in comparison with clay minerals, which decreases the ability of sand particles to hold and retain nutrients (Brady and Weil, 2009). Mulching and incorporation of clay soil and organic matter to sandy soil might have positive effect on soil chemical properties of sandy soil which in turn might improve soil biological properties and growth of physic nut.
Some studies have reported that mulch applications significantly increased soil organic carbon, K, P, root and top biomass of cassava (Cadavid et al., 1998). Sinkeviciene et al.
(2009) reported that mulch increased available P and K contents and crop yield. Application
of mulch on sandy soil with slope of 7% decreased soil and nutrient loss due to leaching (Wakindiki and Danga, 2011). However most of the studies were carried out focusing on the effect of mulching on soil properties and crop yield. There was a limited information regarding on the combined effect of mulch, clay and organic matter on soil chemical and biological properties. This study aimed to quantify the effect of mulch, clay and organic matter on soil chemical and biological properties and growth of physic nut.
Materials and Methods Land Preparation
A field study was carried out at Situbondo, Each Java from April to November 2010. The soil texture is dominated by sand particles with proportion of 77% sand, 17 % silt and 6% clay.
The site was chosen because it has been established as a seeding production area for jatropha (physic nut).
Stems of physic nut cultivar IP2 were grown at poly bags for 30 days before they were transplanted to the plot size of 9 m2. Planting space of physic nut stem was 3 m x 3 m, so each plot consisted of 9 stems. Application of urea 50 g/plant and Ponska 100 g/plant were added twice, at 20 and 50 days after transplanting. The soil was iririgated periodically with interval of 10 days.
Experimental Design
The treatments were three kinds media growth of physic nut, namely (1) Sandy soil as a control, (2) Sandy soil + 10 % clay soil + 1.6% organic matter, and (3) Sandy soil + Mulch+
10% clay soil + 1.6% organic matter. There were eight replicates of each treatment. The arrangement of treatments used a Randomized Block design.
Addition of Mulch, Clay Soil and Organic Matter
Two days after transplanting of physic nut stems, mulch of C. juncea straw was spread out manually in about 10 cm thick layer to the sandy soil with had been incorporated with 10%
clay soil and 1.6% organic matter. Clay soil (67% clay) was collected from sub soil of the land located nearby experimental site. The clay soil was added with the rate 10%
(equivalent to 248 kg/plot or 276 tones/ha). Crotalaria juncea was used as a source of organic matter which was planted on another plot 45 days before it was added to the sandy soil. The organic matter was added at rates of 1.6% (equivalent to 61.7 kg/plot or 69 tones/ha).
Soil Chemical Properties Measurements
Soil organic C content was measured by Walkey Black Method, total nitrogen was determined employing Kjehldahl procedure, soil available phosphorus was measured using Bray 1 methode, exchengable soil potassium was measured by Flame photometric. Soil samples were collected as bulk samples at 30 and 60 days after treatment (DAT).
Soil Biological Properties Measurements
Isolates extracted from soil samples were cultured on spesific media. To culture bacteria and actinomycetes, tryptic soy agar media was used. Fungi were cultured on Martin media agar. Soil was sampled twice, at 30 and 60 DAT.
Plant Growth Measurements
Variables measures were plant height and number of leaf of physic nuts. Measurements were done on three plants per plots which were choosen randomly. Plant height and number leaf were measured at 30, 60 and 90 DAT.
Results and Discussion Soil Chemical Properties
All treatments applied on sandy soil significantly improved the soil chemical properties. The highest soil C organic content was in plot where sandy soil was covered with mulch and added with clay and organic matter (Table 1). Covering sandy soil with mulch which the soil had been added with clay and organic matter had C organic content 42% and 46% higher than untreated sandy soil at 30 and 60 days after treatment respectively. Addition of clay and organic matter did not significantly increase C organic content of sandy soil. Increasing of soil C organic content on the sandy soil covered with mulch and added with clay and organic matter might be due to decreasing loss of the materials by leaching during irrigation of the soil. Atreya et al. (2005) reported that mulching of acidic sandy loam reduced annual soil organic matter by 52%.
Table 1. Effect of mulch, clay and organic matter on C organic content of sandy soil at 30 and 60 days after treatment (DAT)
Treatments C organic content (%)
30 DAT 60 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
0.74 a 0.84 a 1.05 b
0.76 a 0.87 a 1.11 b
LSD 5% 0.16 0.22
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
Effect of treatment on sandy soil on soil total nitrogen content is presented in Table 2.
Mulching of sandy soil which had been added with clay and organic matter signinificantly increased soil nitrogen content by 18% at 30 DAT.
The treatments also significantly increased available phosphorus and potassium content of the sandy soils. Mulching the sandy soil which had been added by clay and organic matter increased soil phosphorus content by 93% and 67% at 30 DAT and 60 DAT respectively (Table 3). The sandy soil covered by mulch and added with clay and organic matter had an exhangeable potasssium content 101 % and 48 % at 30 DAT and 60 DAT respectively than untreated sandy soil at the same date of soil sampling (Table 4).
Table 2. Effect of mulch, clay and organic matter on total nitrogen (N) content of sandy soil at 30 and 60 days after treatment (DAT)
Treatments N content (%)
30 DAT 60 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
0.11 a 0.11 a 0.13 b
0.10 0.10 0.12
LSD 5% 0.01 n.s
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter, ns = not significant
Table 3. Effect of mulch, clay and organic matter on available phosphorus (P) content of sandy soil at 30 and 60 days after treatment (DAT)
Treatments Available P2O5 content (%)
30 DAT 60 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
21.50 a 20.68 a 41.49 b
29.80 a 24.10 a 49.80 b
LSD 5% 5.28 16.63
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
Table 4. Effect of mulch, clay and organic matter on exchangeable potassium (K2O) content of sandy soil at 30 and 60 days after treatment (DAT)
Treatments Exch K2O content (%)
30 DAT 60 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
0.68 a 0.84 b 1.37 c
0.71 a 0.81 a 1.05 b
LSD 5% 0.17 0.21
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
The positive influence of organic mulches on enriching of soil nutrients is well documented.
Saroa and Lal (2004) found that mulching enriched total phosphorus concentration in the soil after 4 years of mulching from 601 up to 658 mg/kg and from 491 up to 694 mg/kg after 11 years of mulching. Wakindiki and Danga (2011) reported that application of straw mulch increased soil nitrogen, phosphorus and potassium concentrations. They attributed that increasing the nutrients in mulched soil due to minimization of soil and nutrients losses. In the present study, the soil nutrients increased in sandy soil covered with mulch and added with clay and organic matter might be due to minimization of soil loss and increasing the holding capacity of the sandy soil as a consequence of addition of clay and organic matter.
Soil Biological Properties
This study demonstrated that mulching of sandy soil which had been added with clay and organic matter enhanced soil biological properties which was expressed by increasing population of soil microorganisms. Table 5 indicated that sandy soil covered with mulch and incorporated with clay and organic matter had the highest population of soil fungi.
Compared to the untreated sandy soil, mulching of sandy soil which had been added with clay and organic matter was occupied by fungi more than three folds and two folds at 30 DAT and 60 DAT respectively.
Table 5. Effect of mulch, clay and organic matter on fungi population of sandy soil at 30 and 60 days after treatment (DAT)
Treatments Population of Fungi (x103 cfu/ml)
30 DAT 60 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
5.00 a 11.25 b 16.87 c
9.62 a 16.37 b 20.62 c
LSD 5% 3.22 3.81
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
Treated sandy soil with mulch, clay and organic matter also had the highest population of soil bacteria (Table 6). The treatments increased population of soil bacteria by three folds and 1.5 folds at 30 DAT and 60 DAT respectively.
Table 6. Effect of mulch, clay and organic matter on bacteria population of sandy soil at 30 and 60 days after treatment (DAT)
Treatments Population of Bacteria (x103 cfu/ml)
30 DAT 60 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
8.12 a 15.87 b 24.37 c
27.62 a 40.00 b 46.12 b
LSD 5% 4.63 7.27
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
The effect of mulch to the sandy soil which had been added with clay and organic matter on population of actinomycetes is presented in Table 7. The treatments caused the sandy soil had the highest population of actinomycetes. Compared to the untreated sandy soil, addition of mulch, clay and organic matter to sandy soil increased population of actinomycetes by 21% and 46% at 30 DAT and 60 DAT.
Some studies have reported the positive effect of mulch on soil microorganisms population.
Augmentation of population of soil fungi, bacteria and actinomycetes by mulching was reported by Gaur and Mukherjee (1980). Mundy and Agnew (2002) found that mulching increased fungi population of soil under vineyard. They attributed that increasing of soil microorganisms populations were due to increasing soil water content and decreasing soil temperature which were suitable conditions for soil microorganisms. Kumar et al. (2010)
reported that C. juncea used as bio-mulching increased soil water holding capacity by 56.9%
and soil moisture by 68.5% at 30 cm depth.
Table 7. Effect of mulch, clay and organic matter on actinomycetes population of sandy soil at 30 and 60 days after treatment (DAT)
Treatments
Population of Actinomycetes (x103 cfu/ml)
30 DAT 60 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
8.87 a 10.50 b 10.75 b
9.12 a 11.37 b 13.37 c
LSD 5% 1.58 1.68
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
In the present study, combined influence of mulch, clay and organic matter might occur on soil biological properties improvements. A previous study found that more soil microorganisms were present in soil fraction with a high content of clay and organic matter (Van Gestel et al. 1996).
Plant Growth
Mulching of sandy soil which had been added with clay and organic matter increased plant height and number of leaf of physic nut. Physic nuts grown on mulched sandy soil and added with clay and organic matter taller more than 42%, 30% and 28% than those growth on untreated sandy soil at 30, 60 and 90 DAT respectively (Table 8).
Table 8. Effect of mulch, clay and organic matter on plant height of physic nut growth on sandy soil at 30 and 60, and 90 days after treatment (DAT)
Treatments Plant Height (cm)
30 DAT 60 DAT 90 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
46.25 a 55.37 b 65.45 c
73.50 a 81.83 b 95.70 c
97.66 a 107.00 b 124.62 c
LSD 5% 4.75 4.89 9.28
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
Sandy soil treated with mulch, clay and organic matter also caused physic nut had the most number of leaf (Table 9). The treatments increased number of leaf by 97%, 70% and 47% at 30, 60 and 90 DAT.
Similar results of the influence of mulch on plant growth development was reported by Arin and Ankara (2001) and Salman et al. (1992). The pointed out that mulching increased soil temperature so that vegetative development of tomatoes was enhanced. In this present study, increasing of plant height and number of leaf of physic nuts grown on mulched sandy soil and added with clay and organic matter might because the treatments improved soil physical and biological of sandy soils which created favourable conditions for root growth. A
previous study reported that addition of clay and organic matter to sandy soil induced vegetative growth of subterranean clover which was indicated by increasing root length and fresh weight of shoots (Djajadi, 2007).
Table 9. Effect of mulch, clay and organic matter on number of leaf of physic nut growth on sandy soil at 30 and 60, and 90 days after treatment (DAT)
Treatments Number of Leaf
30 DAT 60 DAT 90 DAT
SS (control)*)
SS + 10% CS+ 1,6% OM SS + M + 10% CS + 1,6% OM
53.75 a 81.37 b 106.08 c
125.16 a 151.83 b 211.20 c
197.33 a 238.08 b 290.66 c
LSD 5% 8.90 15.60 15.93
*) SS = Sandy Soil, M = Mulch, CS = Clay Soil, OM = Organic Matter
Conclusion
Mulching of sandy soil which had been added with clay and organic matter improved soil chemical and biological properties of sandy soil which result in enhancing growth of physic nut. Nutrients contents (C organic, total N, availability P2O5 and exch. K2O) of sandy soil were increased by addition of mulch, clay and organic matter. The treatments also developed population of soil fungi, bacteria and actinomycetes and also enhanced the plant height and number of leaf of physic nut.
References
Arin, L. and S., Ankara. 2011. Effect of low-tunnel, mulch and pruning on the yield and earliness of tomato in unheated glasshouse. J. Appl. Hort., 3(1): 23-27.
Atreya, K., S., Sharma, and R.M., Bajracharya. 2005. Minimization of soil and nutrient losses in maize-based cropping systems in the mid-hills of Central Nepal. Kathmandu University Journal of Science, Engineering and Technology. 1 (1): 1-9.
Brady, N.C. and R.R., Weil. 2009. Elements of the Nature and Properties of Soil. Pearson Prentice Hall, New Jersey. 614 pp.
Cadavid, L. F., M. A., El-Sharkawy, A., Acosta and T., Sánchez. 1998. Long-term effects of mulch, fertrilization and tillage on cassava grown in sandy soils in northern Colombia. Field Crops Research 57(1): 45-56.
Daey O., K., Francis, G., Franken, Y.J., Rijssenbek, W., Riedacker, A., Foidl, N., Jongschaap, R.E.E. &
Bindraban. 2007. "Position Paper on Jatropha curcas. State of the Art, Small and Large Scale Project Development", Expert seminar on Jatropha curcas L. Agronomy and geneticsPublished by FACT Foundation, Wageningen, the Netherlands.
Djajadi. 2007. The Roles of Added Clay and Organic Matter in Stabilising Aggregates in Sandy Soils.
PhD Thesis. The University of Western Australia.
Farrington, P., Campbell, N.A. 1970. Properties of deep sandy soils and the growth of Lovegrass, Eragrostis curvula (Schrad.) Nees. Australian Journal of Soil Research 8: 123–132.
Gaur, A.C., and D., Mukherjee. 1980. Recycling of organic matter through mulch in relation to chemical and microbiological properties of soil and crop yields. Plant and Soil 56: 273-281.
Kumar, K., R.H., Reddy., P.S., Sinha, J., Tirkey, M.K., Singh, and B.C., Prasad. 2010. Impact of leguminous biomulching on soil properties, leaf yield, and cocoon productivity of tropical Tasaculture under rain-fed conditions. Journal of Entomology. 7 (4): 219-226.
Mundy, D.C., and R.H., Agnew. 2002. Effects of mulching with vineyard and Winery waste on soil fungi and botrytis bunch rot in marlborough vineyards. New Zealand Plant Protection 55:135-138.
Salman, S.K., A.F., Abou-Hadid, I.M.J., Beltagy and A.S., Beltagy. 1992. Plastic house microclimate as affected by low tunnels and plastic mulch. Egyptian J. of Hort. 2: 111-119.
Saroa, G.S., and R., Lal. 2004. Mulching effect on phosphorus and sulfur concentrations in Miamian soil in central Ohio, USA. Land Degradation Development. 15: 351-356.
Sinkevičienė, A., D., Jodaugienė, R., Pupalienė and M., Urbonienė. 2009. The influence of organic mulches on soil properties and crop yield. Agronomy Research 7(I):485–491.
Van Gestel, M.N., R., Merckx, and K., Vlassak. 1996. Spatial distribution of microbial biomass in microaggregates of silty-loam soil and the relation with the resistance of microorganisms to soil drying. Soil Biology and Biochemistry 28: 503-510.
Wakindiki, I.I.C. and B.O., Danga. 2011. Effect of straw mulch application on nutrient concentration in runoff and sediment in a humid regionin Kenya. African Journal of Agricultural Research 6(3):
725-731.