To reduce the load on underground water, transplanting close to the onset of monsoon is an important step of the water-saving policy for sustainable rice cultivation in the state. In view of this, there was an urgent need to develop short-duration rice varieties which when transplanted late (close to the onset of monsoon) doesn’t show yield decline. To address this issue, during the last 11 years, PAU recommended 11 short/medium duration rice varieties which are now grown in more than 70 per cent area in the state. The complete agronomic package of practices for these varieties has been developed.
Dr GS Mangat, Additional Director of Research (Crop Improvement), informed that the agronomic data collected by PAU on transplanting date clearly indicates that transplanting around June 25 results in the highest yield of most of the varieties. The variety PR 126 performs even better under July transplanting. The flowering period of early transplanted crop coincides with high temperature, which results in lower yield due to panicle sterility and low grain weight, he told.
Further, he disclosed, “During Kharif 2022, the incidence of Southern Black Streaked Dwarf Virus was noticed. Although during 2023, no incidence of this virus was reported, still we have to be very vigilant about it.” Farmers are advised to keep surveying the fields right from nursery sowing for the presence of plant hoppers (white-backed plant hoppers) which spread this disease, he advised. “For insect surveillance, light a bulb near the nursery/field as the insects are attracted towards light during the night. Upon the appearance of plant hoppers, spray any of the recommended insecticides for the control of white-backed plant hoppers.
Moreover, it was noticed that stunted plants were comparatively less in late transplanted rice (Table 1). Therefore, sowing of early nursery (before May 25) and early transplanting (before June 25) should be avoided,” he urged.
Dr Buta Singh Dhillon, Rice Agronomist, observed that transplanting early in the season allows the insect-pests to have more number of generations. These observations have been noticed particularly for stem borers of rice (yellow, white and pink) in various studies conducted at PAU, he revealed.
Elaborating, Dr Dhillon pointed out that the heavy build-up of pests such as stem borers and plant hoppers poses a serious threat to the basmati crop, which is more vulnerable and matures late. This compels the farmers to resort to heavy and late sprays, causing residue issues and thereby undermining the export of basmati. The buildup of the pest on the rice crop beyond a threshold can prove to be a threat even to the succeeding wheat crop as happened in the case of pink stem borer after 2019 rice harvest, he warned. Moreover, false smut and sheath blight diseases also show higher severity in early transplanted rice, he cautioned.
Table 1: Grain yield (q/acre), water saving and incidence of virus disease (%) under different dates of transplanting (Average of three years)
|
Date of transplanting |
PR 126 |
PR 131 |
PR 121 |
Saving of irrigation water (%) over June 15 |
#Incidence of virus disease (% plants stunted) |
|
15 June |
29.6 |
36.8 |
32.3 |
- |
16.0 |
|
25 June |
34.8 |
38.0 |
33.5 |
5.6 |
9.8 |
|
5 July |
37.5 |
34.6 |
32.2 |
11.0 |
0.7 |
|
15 July |
36.1 |
32.0 |
29.0 |
16.8 |
0.6 |
#Data averaged across varieties during 2022
For higher yield of the above-mentioned varieties, it is recommended to apply 90 kg urea per acre and 25 kg Zinc sulphate (21%) or 16.5 kg Zinc sulphate (33%), advised Dr Dhillon. “Avoid excessive and untimely use of fertilizers. Due to sufficient window between wheat harvesting and transplanting of PR varieties, green manuring becomes feasible which will help to improve physical and chemical properties of soil along with saving of chemical fertilizers,” he suggested.
