Assessment of germination behaviour and seed spacing accuracy of soybean, pigeonpea and chickpea in intercropping planter system

Introduction

The intercropping is a multiple cropping practice involving growing two or more crops and have opened up new horizons to augment pulse crop productivity per unit area per unit time. The main purpose of intercropping is to produce a greater yield on a given piece of land by making use of resources that would not be utilized by a single crop efficiently. Intercropping might positively impact on the future food problems in developing countries. In India, soybean is grown in an area of 10.84 million hectares with an annual production of about 14.48 million tonnes and productivity of 1354 kg/ha. In Chhattisgarh Soybean occupies 121.42 thousand ha area with a yield of 1050 kg/ha (Anonymous, 2016) [1] . In Chhattisgarh, maximum area and production of soybean come under Rajnandgoan followed by Kabirdham, Durg, Bemetara, and Mungeli districts. India accounts for 90% of the world's pigeonpea growing area and 85% of the world's production. It is grown in an area of 3.88 Mha with the production of 3.17MT and productivity of 849 kg/ha. Chhattisgarh state has a good agro-ecological situation for chickpea production. It is grown over an area of 0.2 million hectares with an annual production of 242.7 thousand tonnes and an average productivity of 1035 kg/ha (Anonymous, 2016) [1] . Intercropping of pigeon pea with soybean has proved successful without any adverse effect on pigeonpea (Ahlawat et al. 1982, Prasad et al. 1985, Maurya, 2000 and Maurya and Rathi, 2000) [4,7,5,6] . Commercial sowing equipment such as seed drill and seed-cum-fertilizer drill operated by animal, power tiller and tractor which meter high and non uniform seed rate, causing thinning as an extra operation. Pandey (2009) [2] reported that the planter provide desired plant population with uniform plant spacing and depth of operation, which results in uniform crop stand and hence, reduces the cost of cultivation by eliminating thinning operation as well as saves seed and fertilizer. Jiyuan (2025) resulted critical insights for optimizing the nutritional and functional properties of chickpeas via sprouting and established a scientific basis for the development of functional foods from germinated chickpeas, underscoring their potential to support dietary health and wellness. The seed rate in sowing with the seed drill is quite high and thinning becomes essential to maintain the optimum plant stand and to ensure each plant get the desired quantity of sunlight, water and nutrients. This could be achieved by planting of different sizes of seeds with the help of appropriate planters (Kepner et al. 1987) [9] .

Methodology

The study was conducted to assess the germination behaviour and seed spacing accuracy of soybean, pigeon pea and chickpea in an intercropping planter system. The experiment included laboratory germination testing of seeds and evaluation of seed spacing performance of the developed intercrop planter under field/laboratory conditions.

Selection of Crops and Seed Samples

Healthy and graded seeds of soybean, pigeon pea and chickpea were selected for the study. The physical properties of seeds such as size, shape and seed dimensions were considered for suitability in the seed metering mechanism of the intercrop planter (Table 01).

Germination Test

The germination test of soybean, pigeon pea and chickpea seeds was conducted using the standard germination test procedure. Random seed samples from each crop were taken and tested under controlled laboratory conditions.

• One hundred seeds from each crop were used for germination testing. • Seeds were placed on moist germination paper/tray and maintained at suitable moisture and temperature conditions. • Observations on germination percentage were recorded after the recommended germination period for each crop. • Normal seedlings were counted and germination percentage was calculated using standard procedures.

The germination percentage was calculated as:

Development of Intercrop Planter

The intercrop planter was designed and developed for sowing soybean, pigeon pea and chickpea under intercropping conditions. The design of the planter was based on seed size, crop spacing requirement and operational suitability for intercrop planting. Proper consideration was given to row spacing, seed metering mechanism and frame arrangement to facilitate simultaneous sowing of different crops.

Characteristics of soybean variety

JS-9752 is most common variety in Chhattisgarh which matures in 95-100 days having medium plant height of 60 to 80 cm. This variety contains 40% protein and 20% oil. The average test weight was 9 to 10g per 100 seed. This variety has prolonged germination capacity. This variety is resistance to yellow vein mosaic, root rot, bacterial spot and diseases. This variety can also be grown in water logged areas and yield potential of 25 to 30q/ha.

Characteristics of pigeonpea variety

Rajive Lochanis the variety developed in IGKV which mature at 180-190 days and its yield is 18-20q/ha.

Characteristics of chickpea variety

Chickpea (Cicerarietinum L.) variety 'JG-130' (Jawahar Gram-130) was grown as test crop. It was released from JNKVV, Jabalpur in 2002. Its parentage is (PG 5 × Narsingpur bold) × JG-74. It is a bold seeded variety and having brown seed colors. The crop duration is about 110-115 days and having yield potential 15-20 q/ha.

Agronomical practices

Suitable agronomical condition and practices for higher production in intercropping practices of soybean, pigeonpea and chickpea are given at Table 2.

Results and Discussion

Germination Test for Soybean, Pigeonpea and Chickpea Germination test of soybean Soybean seeds were kept in wetted bottling crop paper for one week at 25-30 ˚C to determine the germination percentage.

Normal germination percentage was found to be 76.5% whereas 17.75 and 5.5% was observed abnormal and dead respectively as shown in Table 3.

Germination test of pigeonpea

The normal germination was observed to be 83.75% whereas 11.5% was abnormal and 5% seed were dead as shown in Table 4.

Germination test of chickpea

The average germination percentage was found to be 85% are normal for proper seed germination while 9.5% was abnormal and 5.5% seeds were dead as shown in Table 5.

Seed Spacing Accuracy for Intercropping

The existing multicrop planter was evaluated for sowing soybean and pigeonpea under intercropping conditions. It was observed that the planter was unable to maintain the recommended seed-to-seed and row-to-row spacing of soybean and pigeonpea accurately. In addition, the spacing uniformity of pigeonpea seeds was not satisfactory during sowing operation.

To overcome these limitations, an intercrop planter system was assessed for maintaining proper seed spacing and placement accuracy for soybean, pigeonpea and chickpea. The study also included evaluation of germination behaviour of the selected crops under recommended sowing conditions. The germination test for soybean, pigeonpea and chickpea was conducted under laboratory conditions using standard germination procedures. Seed spacing accuracy of the intercrop planter was evaluated by measuring actual seed-to-seed spacing and comparing it with recommended spacing for each crop. There was following parameter were considered:

Metering Plate

There was two inclined metering plate (24 cell and 12 cell) used for soybean, chickpea and pigeonpea. The metering plate that having 24 cell was used to meter the soybean and chickpea at closer distance about 5-10 cm. By using the same metering plate for sowing of pigeonpea higher seed rate obtained and optimum seed to seed spacing 30-35 cm was not maintained. That's why to achieve the same 24 cell was converted to 12 cell by suitable modification in pigeonpea planter Fig. 1.

Seed spacing of soybean and chickpea

When ground wheel rotate 20 revolution then the 12 time and 6 orifices passes of the seed metering plate of soybean and chickpea during rotation of ground wheel Total no of orifices for soybean and chickpea =24x12 +6 =288+6 =294

References

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