Grain yield
Grain yields of different component crops for both the years were presented in Table 1. Perusal of the data presented in Table 1, revealed that, grain yield of all the crops was higher during 2018-19 than 2019-20. This may be due to favourable weather during 2018-19 than 2019-20. Continuous rain after panicle emergence of sorghum and flowering of pulse crops during 2019-20 was severely affected crop yields. The grain yield of sorghum during the year 2018-19 was significantly higher in T
5. However, it was statistically on par with T
6, T
8 and T
7. During the year 2019-20, the grain yield of sorghum was significantly higher in T6 and it was statistically on par with T
5. This indicated that sorghum intercropped with blackgram either in 2:2 or 1:1 ratio resulted in higher grain yield of sorghum than sole sorghum. This might be due to complemented effect of blackgram with sorghum because of growth requirement of both the crops differ in time, resulting in higher per day yield of the system due to temporal complemented effect and also owing to its increased addition of organic matter to the soil. In addition the organic matter might have increased the moisture and nutrient nutrition which favours the good growth of sorghum. Further, blackgram fixes atmospheric nitrogen in to the soil through root nodulation. This nitrogen is available to sorghum crop at later stages. The findings werein corroboration with the findings of
Dai et al., (2019), Chen et al., (2018), Singh et al., (2020) and
Choudhary and Choudhary (2016).
Among intercrops, blackgram recorded higher yield followed by green gram and chickpea (Table 1). This may be due to genetic potential of the crops. The chickpea yield under both sole and intercropping was very low (Table 1). The high intensity rain during crop growing period might be severely affected chickpea yield. In both the years, blackgram, greengram and chickpea yields were reduced to a considerable extent under intercropping compared to the respective sole crop yields (Table 1). This may be due to severe competition from sorghum for water and nutrients and also reduction of plant population of blackgram/ greengram/ chickpea under intercropping.
Sorghum-equivalent yield (SEY)
The (SEY) was higher in intercropping of sorghum with legumes as compared to sole crops of sorghum, blackgram, greengram and chickpea (Table 2). The treatment T6 resulted in significantly higher SEY (3628 kg ha
-1). However, it was statistically on par with T5 (3454 kg ha
-1). The treatments T6 and T5 registered 51.0 and 43.7% higher SEY respectively, than T
1 (sole sorghum) (Table 2).The higher SEY in these treatments was due to higher sorghum yield in addition to intercrop (blackgram) yield. Further, the sale price of blackgram was higher than sorghum, which also led to higher SEY. Among intercrops, blackgram registered higher yield than other intercrops under intercropping (Table 2). Because of higher sale price and relatively higher yield, the treatment T
2 was found next best treatment. The treatment T
2 was recorded with 26.0% higher SEY than T
1. Intercropping greengram/ chickpea with sorghum recorded higher SEY than sole sorghum (T
1). The treatments T
7 and T
8 registered 17.2 and 14.4%higher SEY respectively, than T
1. Similarly, the treatments T10 and T9 registered 6.8 and 6.2% higher SEY respectively, than T
1. Similar findings were reported by
Biru et al., (2004), Kumar et al., (2011) and
Ajit Panhale et al., (2016).
Net monetary returns
Net monetary returns (Rs ha
-1) were influenced by treatments during both the years of investigation (Table 2). All sorghum based intercropping systems proved their superiority than sole crops. The highest net monetary returns were recorded with T6 (Rs 45645 ha
-1) and it was followed by T5 (Rs 43142 ha
-1) and T
7 (Rs 37834 ha
-1) (Table 2). The treatments T
6, T
5 and T
7 resulted in 138.5, 125.4 and 97.7% higher net return respectively than T
1. This might be due to higher SEY in these treatments. Similar results were reported by
Angadi et al., (2004). Net return from T
2 was the next best treatment (Table 2). This was because of higher yield and sale price of blackgram. Net return from T
8, T
9 and T
10 was also higher than T
1 (Table 2). This indicated that intercropping in sorghum was more profitable than sole sorghum cultivation.
Abdel-Wahab and Abdel-Wahab (2021) reported that higher economic returns realized when faba bean was included as intercrop in flax.
Land equivalent ratio (LER)
The LER values in different intercropping systems were greater than unity, indicating the yield advantage from intercropping systems.Among the intercropping systems, T
10 recorded the highest LER and it was followed by T9.
Kumar et al., (2005) and Binoy
Chhetri and Sinha (2020) also reported that LER was found more than 1 in all the intercropping systems and the maximum LER in maize + cowpea (2:2) intercropping system compared to the 1:1 and 1:2 ratio. However, LER did not reflect absolute level of yield, but it was considered as an important variable for the yield target of an intercropping study
(Sharma and Behera, 2009).
Area time equivalent ratio (ATER)
The ATER was also greater than unity in all the cases of intercropping systems. The 2:2 row ratio combination (T
6, T
8 and T
10) has recorded higher ATER values, which appeared to be advantageous and indicated higher productivity in comparison to 1:1 row ratio combination (T
5, T
7 and T
9). This was owing to greater resource use and resources complementarily when inter crops grown in 2:2 row ratio. The highest ATER values of the system established that growth requirement of both the crops differ in time, resulting in higher per day yield of the system due to temporal complemented effect. The highest ATER values recorded with T
10.
Kheroar and Patra (2014) also reported that 2:2 maize blackgram intercropping system recorded the highest ATER value that was achieved owing to development of spacial complementarities.
Anishetra and Kalaghatagi (2021) also reported that higher ATER was recorded in sesame+foxtail millet in 2:4 row proportions.
Aggressivity
The competitive ability of sorghum, blackgram, greengram and chickpea was also estimated through aggressivity. The results showed that the variation of aggressivity depended on the configuration of the intercropping systems (Table 3). The aggressivity values indicated that sorghum dominated the blackgram, greengram and chickpea in both the row ratios tested (Table 3). Aggressivity values were positive (+ve) in sorghum which obviously indicated the sorghum was the dominant crop, where the associated intercrops
viz., blackgram, greengram and chickpea appeared to be the dominated ones having negative (-ve) values (Table 3). Between the two spatial arrangements, 1:1 intercropping (T
5, T
7 and T
9) resulted in higher values of aggressivity, which denoted higher interspecific competition. Among all the intercropping systems, T10 recorded the lowest values of aggressivity.
Sharma et al., (2006) reported that maize intercropped with cowpea and rice bean (2:1) was found to be a compatible intercropping system with lower values of aggressivity.
