Zinc partitioning in basmati rice varieties as influenced by Zn fertilization

Zinc(Zn) ferti-fortification using different sources and methods in Zn deficient soils is being advocated to increase Zn concentration in rice kernel as an alternative to pursuing greater Zn-use efficiency(ZnUE). A two-year field study was conducted to assess the effect of Zn application on Zn content and uptake at several growth stages and in several parts of the rice kernel: hull, bran, and the white rice kernel. Variety ‘PB 1509' with 1.25 kg Zn ha^(-1) as Zn-EDTA + 0.5% foliar spray(FS) at maximum tillering(MT) and panicle initiation(PI) stages registered the highest Zn content in hull, bran, and white rice kernel. Among parts of the rice kernel, Zn concentration decreased in the order hull > bran > white rice kernel,indicating that brown rice kernels are much denser in Zn content than polished rice.Considering the higher Zn accumulation in the bran, brown rice consumption, especially in Asia and Africa, could be recommended to overcome Zn malnutrition. The variety ‘PB 1401'showed the highest Zn uptake in rice straw, while ‘PB 1509' showed the highest Zn uptake in hull and white rice kernel. Application of 1.25 kg Zn ha^(-1)(Zn-EDTA) + 0.5% FS at MT and PI and 2.5 kg Zn ha^(-1) ZnSO_4·7H_2O(ZnSHH) + 0.5% FS at MT and PI resulted in higher Zn uptake than other treatments. On average, about one third of total Zn uptake remained in the white rice kernel, with the remaining two thirds accumulating in both hull and bran of brown rice. Zn-EDTA along with 0.5% FS, despite the application of a lower quantity of Zn leading to the highest Zn mobilization efficiency index(ZnMEI) and Zn-induced nitrogen recovery efficiency(ZniNRE), produced the highest kernel yield. However, of the two Zn sources, Zn-EDTA contributed more to the increase in ZnUE than did ZnSHH.

Long-Term Conservation Agriculture and Intensified Cropping Systems:Effects on Growth,Yield,Water,and Energy-use Efficiency of Maize in Northwestern India

Conservation agriculture(CA)-based best-bet crop management practices may increase crop and water productivity, while conserving and sustaining natural resources. We evaluated the performance of rainy season maize during 2014 under an ongoing long-term trial(established in 2008) with three tillage practices, i.e., permanent bed(PB), zero tillage(ZT), and conventional tillage(CT) as main plots, and four intensified maize-based cropping systems, i.e., maize-wheat-mungbean, maize-chickpea-Sesbania(MCS), maizemustard-mungbean, and maize-maize-Sesbania) as subplot treatments. In the seventh rainy season of the experiment, maize growth parameters, yield attributes, yield, and water-and energy-use efficiency were highest at fixed plots under ZT. Maize growth parameters were significantly(P < 0.05) superior under ZT and PB compared with CT. Maize yield attributes, including cobs per m^2(7.8), cob length(0.183 m), grain rows per cob(13.8), and grains per row(35.6), were significantly higher under ZT than CT; however, no significant effect of cropping systems was found on maize growth and yield attributes. Zero tillage exhibited the highest maize productivity(4 589 kg ha^(-1)). However, among the cropping systems, MCS exhibited the highest maize productivity(4 582 kg ha^(-1)). In maize, water use was reduced by 80.2–120.9 mm ha-1under ZT and PB compared with CT, which ultimately enhanced the economic water-use efficiency by 42.0% and 36.6%, respectively. The ZT and PB showed a 3.5%–31.8% increase in soil organic carbon(SOC) at different soil depths(0–0.45 m), and a 32.3%–39.9% increase in energy productivity compared with CT. Overall, our results showed that CA-based ZT and PB practices coupled with diversified maize-based cropping systems effectively enhanced maize yield and SOC,as well as water-and energy-use efficiency, in northwestern India.