Impact of tillage and integrated plant nutrient management on cereal-legume cropping system uner irrigated and non-irrigated conditions.

Abstract

A series of field experiments were conducted to evaluate the integrated application of organic and inorganic nutrient source, cropping systems and different tillage methods under irrigated and non-irrigated conditions and study their effects on soil physiochemical properties, soil fertility and crop productivity. The experiments were carried out at Agricultural Research Station Serai Naurang, Bannu, Pakistan. Tillage methods included deep (DT) and conventional shallow tillage (CT) while cropping system consisted of wheat-maize-wheat, wheat-mungbean-wheat under irrigated condition and wheat-mungbean-wheat, wheat-fallow-wheat under non-irrigated condition. The fertilizers treatments were farmer’s practice T1 (50 % NP), balance inorganic fertilizers T2 (100 % NPK recommended dose i.e. 120, 90 and 60 kg ha-1), integrated inorganic and organic fertilizers T3 (50 % N + 100 % PK + 10 tons FYM ha-1) and T4 (25 % N + 100 % PK + 20 tons FYM ha-1). The experimental design was RCB with split-split plot arrangement having three replications. Tillage was allotted to main plots, cropping system to subplots and fertilizer treatments to sub-subplots. Deep tillage treatment resulted higher soil available water holding capacity, mineral N and lower soil bulk density than CT under both the conditions. Higher wheat straw, grain and total NPK uptakes was observed in DT than CT. The straw and grain yield of wheat significantly increased with deeply ploughed plots under both irrigated and non-irrigated conditions. However, soil organic matter (OM), AB-DTPA extractable P and K, pH, microbial biomass and population was not affected by any tillage methods. Mungbean-wheat cropping system had performed better than maize-wheat or fallow-wheat. Greater soil OM, mineral N, N uptake, microbial biomass and microbial population was recorded in mungbean-wheat rotation than fallow-wheat under non-irrigated condition, whereas higher wheat straw and grain yield was recorded in mungbean-wheat compared to maize-wheat rotation under irrigated condition. Similarly, incorporation of FYM either 10 tons with 50 % N + 100 % PK (T3) or 20 tons with 25 % N + 100 % PK (T4) had increased soil available water holding capacity, organic matter, mineral N, AB-DTPA extractable P and K, microbial biomass and population but decreased soil bulk density under both conditions. Greater straw N, P and K contents were measured in plots having 50 % N + 100 % PK + 10 tons FYM ha-1 and 25 % N + 100 % PK + 20 tons FYM ha-1 compared to the plots receiving sole mineral fertilizers, whereas grain N was increased in plots receiving balance inorganic fertilizers under both the conditions. Integrated application of 50 % N + 100 % PK with 10 tons FYM ha-1 had improved straw, grain and total N, P and K uptakes compared to other treatments under each conditions. Fertilization of 50 % N + 100 % PK with 10 tons FYM ha-1 had further improved wheat grain yield with 56 % increase under irrigated condition and 49 % increase over farmer’s practice under non-irrigated condition followed by the plots receiving sole recommended 100 % NPK. The summer crops of maize and mungbean responded significantly to combine application of organic and inorganic fertilizers. Addition of 50 % N + 100 % PK + 10 tons FYM ha-1 had increased maize grain and stover yield compared to the other treatments under irrigated condition. Plots incorporated with 50 % N + 100 % PK + 10 tons FYM ha-1 or 25 % N + 100 % PK + 20 tons FYM ha-1 produced comparable yield of mungbean, but significantly higher from plots having sole inorganic fertilizers under both the conditions. Integrated use of 50 % N + 100 % PK + 10 tons FYM ha-1 with DT under wheat-mungbean-wheat cropping system had improved crop productivity and soil fertility beside soil health and environmental benefits and thus recommended for irrigated and non-irrigated wheat sowing in agro-climatic condition of Bannu, Pakistan.