ABSTRACT
Groundwater recharge is the most important component in all the water balance studies and in ground water development projects as a part of sustainable groundwater management. Norms set by the Groundwater Resource Estimation Committee, GEC-2015 was used for the estimation of recharge. The study was conducted for the Bandar canal command area constituting the Krishna Central Delta in Andhra Pradesh. Following the norms of GEC-2015, the recharge was estimated for the past decade from 2012-13 to 2021-22 and it was found that recharge rate ranged from 438135.8 ha-m in the year 2015-16 to 1677730 ha-m in the year 2013-14. While computing the gross recharge, recharge attributed by rainfall, canal seepage, irrigation return flow and from the ponds/tanks are considered. Recharge estimated sheds information on replenishment and improved management of coastal aquifers where seawater intrusion is a major problem.
ABSTRACT
Field experiments were conducted at Agricultural College Farm, Bapatla during Kharif and Rabi seasons of 2017-2018 and 2018-2019 to study the Phosphorus dynamics in relation to nutrient management in rice- blackgram cropping sequence with respect to changes in soil nutrient status. Results of two years (2017-2019) experimentation revealed that at all growth stages of rice, significantly highest available nitrogen, phosphorus and potassium in soil were recorded with application of RDNK+Dhaincha @ 10t ha-1 (M3) and this was on par with RDNK+ Sunhemp @ 10t ha-1(M2), whereas lowest was recorded in RDNK (M0) alone in both seasons of study. Among the P levels the available nutrient status (N, P and K) were increased with the increasing level of P from 0 (P1) to 120 kg P2O5 (P5) ha-1, irrespective of the nutrients imposed to rice crop. Significantly highest was recorded in P5 (120 kg P2O5 ha-1) and this was on par with P4 (90 kg P2O5 ha-1), whereas the lowest was recorded in treatment P1 that received 0 kg P2O5 ha-1.