The Growth of Two Cultivars Mung Bean under different Sweet Corn Shelter Density in Sandy Soil Coastal Area

The experiment had been conducted from August to November 2016 at Samas sandy soil coastal area. The research aimed to determine growth response of mung bean sheltered by various density of sweet corn on coastal sandy soil. The experiment used the nested design with two factors with three replications.The first factor was density of sweet corn as shelter consisting of without shelter (S0), planting space of 15 × 40 cm (S1), and planting space of 30 × 40 cm (S2). The second factor was mung bean cultivars compiled of Vima 1 (V1) and Purworejo local cultivar (V2). The data of soil temperature, soil moisture content at the depth of 10 and 20 cm, soil salt content at 10 and 20 cm depth, leaf fresh and dry weight, root fresh and dry wieght, plant fresh and dry weight were collected. The effect of shelter density was on the leaves dry weight at 6 week after planting (WAP), meanwhile the mung bean cultivars influenced the soil moisture at 10 and 20 cm depth; leaves fresh weight, leaves dry weight, root fresh weight, and plant dry weight at 4 WAP. Vima 1 resulted in significantly higher compared to Purworejo local cultivar on soil moisture content in 10 and 20 cm, leaves fresh and dry weight, root fresh weight, plant fresh and dry weight at 4 WAP. There was interaction between sweet corn shelter density and mung bean cultivar on soil salt content at 10 cm (2 WAP), 20 cm (6 WAP), plant fresh weight at 4 and 6 WAP, and plant dry weight at 6 WAP. The best growth of mung bean was observed under higher level density shelter with 15 × 40 cm square planting space due to the deeper soil layer and lower salt content. Received: 18th July 2017; Revised: 18th October 2017; Accepted: 19th December 2017


INTRODUCTION
Mung bean is used for many traditional food, snack, cake and beverage, as well as consumed as vegetable.The increase of mung bean demand was due to the increasing of populations.Therefore, it is necessary to increase the production of mung beans by expanding the harvest area.
Coastal sandy land is one of the sub-optimal area that has long been used as agricultural land in Yogyakarta.The land is shallow and easy soil management because most of the domination of sand.The land must be improved the fertility and the microclimate for appropriate agriculture land.The specific microclimate in coastal sandy land comprises daytime temperatures ranging around 41-42 o C (Auditya et al., 2015) and strong winds from the sea area carrying salt particles (Parwata et al., 2014).The crop needs a shelter to control hight temperature, wind speed, and salinity.
Shelter is used to protect the main crops by creating microclimate conditions that suitable for the growth and development of the main crops (Oliet et al., 2007).Shelter is used as shade plants such as for coffee plantations (Evizal et al, 2012) and tea plantations (Widayat and Rayati, 2011), windbreaking plants such as pine in coastal land (Widodo, 2015), barrier plants for pest control (Inayati and Marwoto, 2011;Aji et al., 2015).In this study, the shelter used was sweet corn plants.Sweet corn has plant height of 60-150 cm, higher than mung beans.The sweet corn plant is expected to be wind breaker.Sweet corn is a valuable horticultural crop.The sweet corn were expected to create the better microclimate that suitable for mung bean.The research aimed to determine growth response of mung bean sheltered by various density of sweet corn on coastal sandy soil.sandy land, Bantul Regency, since August to November 2016.The experiment was arranged in the nested design consisting of 2 factors with three replications.The first factor was the density of sweet corn plant as shelter, which consisted of three levels i.e. without shelter, planting space of 30 × 40 cm (Shelter 30 cm), and planting space of 15 × 40 cm (Shelter 15 cm) .The second factor was cultivar which consisted of Vima 1 (V1) and Purworejo's local mung bean cultivar (V2).The observation was conducted on the soil conditons and the biomass of the mung beans.The data of soil conditions comprising soil temperature, soil moisture content at 10 and 20 cm depth, and salt content at 10 and 20 cm depth were collected by using Electrical Conductivity (EC) method.Plant biomass included the fresh and dry weight of the leaves, roots, and plant.
The data observed were analyzed variance with SAS 9.0 and the least significant difference (LSD) test at alpha 5%.

RESULT AND DISCUSSION
Based on the analysis of variance (Table 1), the shelter density is not affect on the soil temperature, soil moisture content at 10 cm and 20 cm depth and soil salinity at 10 cm and 20 cm depth.The shelter was less effective in lowering the wind speed and inadequate to shade the mung bean area.
There was no significant of the soil temperature, and the salt content at 10 cm depth at 4 WAP, 6 WAP, and at 20 cm in depth at 2 WAP and 4 WAP between the cultivar.However, the soil moisture content of Vima 1 cultivar plot was higher than Purworejo local cultivar at 10 and 20 cm in depth.Vima 1 cultivars had a dense canopy causing lower light interception which can decrease the evaporation.The rate of evaporation is closely related to the moisture savings, the lower the evaporation the higher moisture content (Sudyastuti and Setyawan, 2007).According to Yusuf et al. (2015) the availability of water in the soil will facilitate the process of photosynthesis, by accelerating the translocation of photosynthate supporting the growth of plants.
There was an interaction between shelter density and cultivar on soil salt content at 10 cm (2 WAP) and at 20 cm (6 WAP) (Table 2).Purworejo local cultivar without shelter, Vima 1 under shelter with 30 cm planting space, and Vima 1 under shelter with 15 cm planting space had higher soil salt content level at 10 cm depth compared to other treatment combinations when mung bean plants were at 2 WAP.While salt content of 20 cm 6 WAP, combination of treatment of 30 cm shell of Purworejo local cultivars and Vima 1 cultivar shelters have lower salinity than other combinations treatment.Decrease in soil salt level is influenced by the presence of shelter.The 2 WAP green bean plant is very vulnerable if there is high salt either on the leaf surface or in the soil.Salt levels in the soil will greatly affect the plant.Excess of the salt can cause salinity to the soil.Rice yield and beans in post-tsunami Aceh due to increased soil electric cunductivity (Rachman et al., 2008).
Based on analysis of variance in Table , 3 shelter density treatments did not significantly affect leaves fresh weight at 2, 4, and 6 WAP.Both cultivar had different leaves fresh weight at 4 WAP but not at 2 and 6 WAP.Mung beans at 4 WAP had a greater leaves fresh weight compared to Purworejo local cultivar.Each cultivar has different genetic factors which will affect the morphology of plants according to the growth phase.
According to Table 3, shelter density treatment had an effect on leaves dry weight at 6 WAP while at 2 and 4 WAP, it was contrary.The highest leaves dry weight at 6 WAP was observed in mung bean plants under shelter with both 30 and 15 cm spacing.It was probably because the shelter could increase the plant dry weight.Shelter served as a barrier to salt particles carried by wind from the sea.Soil salinity will decrease mung bean plant growth (Hayat et al., 2010) and crown weight (Mensah and Ihenyen 2009).According to Taufiq and Purwaningrahayu (2013), the salt tolerance of mung beans was different among genotypes.Dry weights of mung beans were different among cultivars in the flowering phase (Taufiq and Purwaningrahayu, 2013).The leaves dry weight of Purworejo local cultivar increased from 4 WAP to 6 WAP and was higher compared to Vima 1.
Based on Table 4, the density of shelter had no significant effect on root fresh and dry weight at 2, 4 and 6 WAP.Both cultivar had significant difference on root fresh weight at 4 WAP but not at 2 and 6 WAP.Vima 1 had a higher root fresh weight than Purworejo local cultivar did.It was assumed that each plant had genetic diversity characterized by differences in plant shape, plant growth, leaves, flowers, fruits, seeds and genotypic characteristics, as well as the ability to grow well under certain environmental conditions.The dry matter production process varies depending on the genotype, environmental conditions, and undertaken cultivation techniques (Gurmu et al., 2009).The root dry weight was not different between cultivars at 2, 4 and 6 WAP.Table 5 showed the analysis results of the plant fresh weight and dry weight at 2 and 4 WAP.Shelter density treatment had no effect on all those parameters.This indicated that the shelter had no effect on the formation of plant biomass.formed from the result of plant photosynthesis and translocation of the source and sink (Greer, 2017).
The dry weight of mung bean plants was significantly different between cultivars at 4 WAP.Vima 1 had a higher plant dry weight than Purworejo local cultivar did.This is allegedly because 4 WAP is the peak of maximum growth of mung beans plants.According to research conducted by Sadeghipour (2009), the biomass of mung bean plants was different among cultivars.
Table 6 showed the interaction between shelter density and cultivar on plant fresh weight and dry weight at 6 WAP.Almost all treatment combinations had high plant fresh weight at 6 WAP except cultivar Vima 1 without shelter.The lowest plant dry weight at 6 WAP was observed in cultivar Vima 1 without shelter and under shelter with 30 cm planting space.Shelter with 15 cm planting space resulted in higher plant dry weight compared the other treatments.

CONCLUSIONS
Sweet corn as crop shelter increased the dry weight of mung beans biomass.Vima 1 had higher

Table 1 .
Soil temperature ( o C) and moisture content (%) of mung bean and salt content (ppm) plot under different shelter density and cultivar Remarks: The numbers in the column in each factor with same letter showed no significant difference

Table 2 .
Soil salt content (ppm) of mung bean plot under different shelter density and cultivars Remarks: The numbers in the column in each factor with same letter showed no significant difference by Duncan's 5%

Table 3 .
Leaves fresh and dry weight (g) of different mung bean cultivars under different shelter density

Table 4 .
Root fresh and dry weight (g) of different mung bean cultivars under different shelter density Remarks: The numbers in the column in each factor with same letter showed no significant difference by Duncan's 5%

Table 5 .
Plant fresh and dry weight (g) of different mung bean cultivars under different shelter density soil moisture content, resulting in the higher roots, leaves fresh, dry weight, root fresh weight, and plant dry weigh at 4 WAP compared to Purworejo local cultivar.The growth of Mung bean under shelter was better than without shelter.: The numbers in the column with same letter showed no significant difference by Duncan's 5% Remarks

Table 6 .
Plant fresh and dry weight (g) of different mung bean cultivars under different shelter density