Annual effects of different organic fertilisers in a baby leaf crops system under tunnel in Southern Italy

Abstract

In a farm devoted to the production of fresh-cut leafy vegetables located in Eboli (Salerno), it was carried out a trial to compare the effects on crops and soil organic carbon (SOC) of biowaste compost, olive pomace compost, buffalo manure applied to soil in two doses (15 and 30 t ha<sup>−1</sup> fresh weight). The amendments were tested in order to start in defining a feasible strategy for the recovery/maintenance of soils in degradation due to the organic matter depletion triggered by the intensive soil tillage and the lack of organic matter returned to soil. In the year following the soil amendment, it was studied the crop sequence: rocket-basil-rocket. Analysis of nitrates concentration in leaves of rocket was carried out on samples of all the treatments picked up in the two cycles of rocket. Along the year, we observed that the higher yields promoted in the first six months (May-September) from the dose 15 t ha<sup>−1</sup>, were obtained with the dose 30 t ha<sup>−1</sup> in the successive six months (November-May). This was due, probably, to the larger stock of total N supplied with dose 30 and its release in time. Buffalo manure amendment showed a higher quickness than composts in the supplying mineral nitrogen to the first crops. On the other hand, nitrates in leaves of rocket exceeded, more frequently, the limits fixed in EU Regulation n. 1258/2011 in the plots amended with buffalo manure. Instead, the treatments with olive pomace compost showed to exceed rarely the EU limits. Under tunnel, the intensive management based on 4-5 crop cycles per year and as much soil tillage, appeared the first cause to explain the lack of significant variation in SOC of plots treated with organic improvers after one year from their distribution. This result let us to suppose the need to study some modifications of the standard farm management in order to reduce the number of soil tillage in a year and, as a consequence, the main stress causing the high carbon mineralisation rate in soil under tunnel.

Quanti-Qualitative Response of Swiss Chard (Beta vulgaris L. var. cycla) to Soil Amendment with Biochar-Compost Mixtures

“…Soil treatment with compost from olive pomace resulted in a lower Swiss chard growth than the other two composts, probably due to the higher C/N ratio (see Table 2) that determined a higher N immobilization in soil, a higher N competition in plants and soil microorganisms and a lower N availability for plant growth. According to this hypothesis are the results of Morra et al [39], who found a higher quickness of buffalo manure amendment than biowaste and olive pomace compost in supplying mineral nitrogen to a rocket crop. Our hypothesis is also supported by previous findings of Garcia-Ruiz et al [40].…”

Introduction of sorghum [Sorghum bicolor (L.) Moench] green manure in rotations of head salads and baby leaf crops under greenhouse

“…Therefore, an amount of organic C of 7.6-8.1-8.2 t ha -1 with BMR 201, BMR 333 and Goliath, respectively, was tilled in the ground. These considerable quantities are comparable to the 7-8.5 t ha -1 of C introduced with 22-27 t ha -1 DM of biowaste or olive pomace composts, respectively, in the experiment carried out by Morra et al (2015) in a baby leaf crop system under greenhouse. N recovered from soil and fixed in sorghum plants ranged from 330 to 406 kg ha -1 .…”

“…the increase of SOC per unit of input) of compost or crop residues decreases with the amount added as shown in medium and long-term experiments by Pagano et al (2008) and Heitkamp et al (2012), respectively. Recently, experiments were carried out in fresh-cut leafy vegetables crop systems under tunnels in Sele river Valley by using olive husk compost, biowaste compost or buffalo manure as organic conditioners (Morra et al, 2013(Morra et al, , 2015. Tests were carried out for one or two years (two-year data not yet published) without modifying the soil tillage regime.…”

“…In this regard, it should be clarified that the seedbed preparation of any crop requires a sequence of chiseling, spading machine, 2-3 rototilling. The lack of significant and repeated soil organic amendment has triggered a decline in soil organic carbon (SOC) under these intensive farming systems (Morra et al, 2015). Bonanomi et al (2011) pointed out that long-lasting soil cultivation under plastic cover in the Sele river basin has negatively affected SOC content, microbial biomass, enzymatic activities, functional and species diversity, soil salinity.…”

Eco-Sustainability of Soils in Baby-Leaf Crop Systems under Tunnel through the Application of C-Rich Inputs: Towards Combating Soil Degradation

“…After the first amendment, in 2013/2014, the sequence rocket-rocket-basilrocket was followed while in 2014/2015, after the second amendment, a rocket-rocket sequence was pursued. Productive and qualitative results related to the first year of the experiment were presented in Morra et al [28]. In this paper, which considers the second year, we focus on the last, major rocket cycle, which occurred in the cycle from November 2014 to April 2015.…”