Pigeonpea is an important pulse crop of the country. In Karnataka, it is extensively grown in the northern part of the state, particularly in the Kalaburagi district and is popularly known as the “Pigeonpea bowl of Karnataka”. Any adverse effect on pigeonpea in this district will affect the state production and productivity. In Karnataka state, this crop occupies 8.81 lakh ha, producing 5.80 lakh tonnes with an average productivity of 658 kg ha^-1. The productivity of pigeonpea in Karnataka is very low compared to the national productivity of 875 kg ha^-1 [1].The lower productivity of pigeonpea in the state is mainly due to erratic and scanty rainfall; prolonged dry spells during critical growth stages such as flowering and pod formation lead to a heavy reduction in the yield. Drought is one of the abiotic stresses that limit agricultural productions.The adverse effects of drought stress can be mitigated by soil management practices, crop establishment, and foliar application of nutrient elements by maintaining an appropriate water level in the leaves due to osmotic adjustment and stomatal performance [5]. It is well established that drought mitigation techniques such as seed treatment with chemicals, foliar application of nutrients and insitu moisture conservation practices play an important role in crop stand establishment and higher production of pigeonpea [8]. Because of slow initial growth and long duration, pigeonpea crop suffers badly due to moisture stress especially during flowering and pod formation stages. Any management techniques to mitigate drought under stress period will help to boost its productivity.

MATERIALS AND METHODS

The field experiment was conducted on shallow black soils at Zonal Agricultural Research Station, Kalaburagi, University of Agricultural Sciences, Raichur (Karnataka), during kharif season of 2017-18, 2018-19 and 2019-20 to findout the effect of drought management practices on growth and productivity of pigeonpea. Eleven treatments were laid out in simple RCBD design with three replications and each consisted of Seed hardening with 2% CaCl₂ (T₁), Vermicompost @ 2.5 t ha^-1 (T₂), FYM @ 5 t ha^-1+2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage (T₃), Mulching with residues @ 5 t ha^-1(T4), Pusa hydrogel  @ 2.5 kg/ha (T₅), Seed hardening with 2% CaCl₂ + Pusa hygrogel @ 2.5 kg ha^-1(T₆), Vermicompost @ 2.5 t ha^-1 +  Pusa hygrogel @ 2.5 kg ha^-1 (T₇), FYM @ 5 t ha^-1+ Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage (T₈), Pusa hydrogel  @ 2.5 kg ha^-1 + Mulching with residues @ 5 t ha^-1(T₉), Pusa hydrogel  @ 2.5 kg ha^-1 applied at 45 DAS (T₁₀)  and Control (T₁₁). Seed hardening with 2% CaCl₂ was done one day before sowing and application of vermicompost, FYM and Pusa hydrogel were done before sowing [19]. Foliar application of 2 % KH₂PO₄ and 2 % KNO₃ was done in the morning hours at flowering and pod development stages. Pigeonpea crop residues (mulches) were applied between two pigeonpea rows to conserve moisture. Pigeonpea variety TS 3R was sown at a 90 cm x30 cm spacing. The soil of the experimental field was clay loam having organic carbon 0.50%, the N status of the experimental field was low (180 kg ha^-1), medium in available P₂O₅ (25 kg ha^-1) while available K₂O status was in high range (350 kg ha^-1). The pH of the experimental site was 8.80 and ECe 0.41 dS/m. The recommended dose of fertilizers, i.e., 25 kg ha^-1 N and 50 kg ha^-1 P₂O₅ were applied in the form of urea and diammonium phosphate respectively as a basal dose. The annual rainfall of 974.9 mm 37 rainy days, 549.80 mm in 38 rainy days and 605.8 mm in 50 rainy days were received during 2017, 2018 and 2019. The observations on plant growth and yield parameters were recorded manually on five randomly selected representative plants from each replication plot separately as per the standard method. The seed and stover yield was recorded from net plot area of each treatment. Economics was calculated based on market price of pigeonpea and cost of cultivation. The data obtained from various growth and yield characters under study were statistically analyzed by analysing variance as described by [3].

RESULTS AND DISCUSSION

Available Soil moisture Dynamics: The beneficial effect ofdifferent drought mitigation techniques could be seen in available soil moisture content at different stages of observations (Table 1).Among the different treatments, maximum soil moisture content was observed under the treatment FYM @ 5 t ha^-1+ Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stageand which was found to be at par with FYM @ 5 t ha^-1+ 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage. During the peak flowering stage (90 DAS), pod filling stage (120 DAS) sufficient soil moisture was recorded during all the 3 years of experimentation and reflected grain yield [13]. Application of FYM @ 5 t ha^-1+ Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage was found to increase soil moisture availability than rest of the treatmentsand produced greater infiltration by reduced runoff and subsequent arresting the evaporation on the infiltrated water apparently contributes to soil moisture gains [2].

Growth andYield Attributes: The data in Table 2 show that treatments had significant effect on growth and yield attributes of pigeonpea. The pooled data of three years indicated that FYM @ 5 t ha^-1+ Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage recorded significantly higher growth and yield attributing characters viz., plant height (187.0 cm), number of primary branches (12.1 plant^-1), secondary branches (14.9plant^-1), pods (147.9 plant^-1), seed yield (47.7 g plant^-1) and 100 seed weight (10.53 g) over control. But, it was found on par with FYM @ 5 t ha^-1+ 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage (T₃). All the drought mitigation practices maintained higher growth and yield attributes as compared to control [4]. The enhanced growth and yield parameters may be attributed to increase in aeration and maintenance of soil moisture, which consequently resulted in better crop growth and development. Enhanced growth and yield parameters in crops grown under moisture conservation technique [12], [18], [22]. Higher growth and yield parameters of pigeonpea grown under 100% RDF + FYM + opening of shallow furrows between two rows at 30 DAS was reported by several workers across the country [2], [21].

Crop Productivity: The data analysed on three years mean basis of crop productivity was given in (Table 4). Among the different drought management practices, FYM @ 5 t ha^-1+ Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage recorded significantly higher seed yield (1392 kgha^-1), stalk yield (3943 kgha^-1) and harvest index (0.25) when compared to rest of the drought mitigation practices. Still, it was found at par with FYM @ 5 t ha^-1+ 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage. Significantly lower seed yield, stalk yield and harvest index were registered under control treatment.The increased productivity of grain and stalk under the above-mentioned treatment resulted from the favourable effects of moisture conservation on growth and yield attributes. Thus, application of FYM @ 5 t ha^-1+ Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stageshowed superiority over other drought mitigation practices particularly during low rainfall years [7], [14], [17], [22]. The impact of Pusa hydrogel application alone was not significant on grain and stalk yield, but has a positive response when applied with organic manures like FYM or vermicompost. Similarly, moisture conservation techniques like vermicompost + Pusa hydrogel improved the grain yield of pigeonpea [6]. Significant improvement in wheat yield was also reported due to hydrogel application [11]. Enhanced yield of Urd crop grown under Pusa hydrogel @ 2.0 kg ha^-1 compared to control [9]. Establishing soil mulch through additional intercultural practices at early and mid stress periods gave yield advantage in different crops [10], [15]. Many authors have reported positive [8] and negative [6] findings in terms of moisture conservation and yield [20].

Economics: Application of FYM @ 5 t ha^-1+ Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage recorded significantly higher gross returns (₹ 83520 ha^-1), net returns (₹ 42520 ha^-1) and B:C ratio (2.04) when compared to the gross returns, net returns and B:C ratio obtained from rest of the drought mitigation practices. However, all the drought mitigation practices recorded significantly higher gross returns, net returns and B: C ratio than RDF only (control) [16]. Significantly higher gross monetary returns, net returns and B: C ratio were obtained in moisture conservation techniques like FYM @ 5 t ha^-1 + Pusa hydrogel  @ 2.5 kg ha^-1 + 2% KH₂PO₄ at flowering + 2% KNO₃ at pod development stage [6]. Application of 100% RDF + FYM @ 5 t ha^-1 + opening of shallow furrows in between two rows and 5% RDF + FYM @ 5 t ha^-1 + opening of shallow furrows in between two rows registered additional gross returns over control during early and mid stress periods in medium duration pigeonpea by conserving moisture [2].

From the above findings, it can be concluded that application of FYM @ 5 t ha^-1 + Pusa hydrogel  @ 2.5 kg ha^-1 + 2 % KH₂PO₄ at flowering + 2% KNO₃ at pod development stageis the best option for mitigating the drought situations. Also, it is economically beneficial for realizing the higher productivity of pigeonpea under rainfed conditions of Karnataka state.

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References

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